6%2E1992-5082

AI AA-92-5082
True Space Transportation: The
Key to a New Era in Space
Operations
PART I
R.Hannigan,
ESYS Ltd.,
Surrey, United Kingdom
PART II
J. Sved,
ERN0 Raumfahrttechnik GmbH,
Bremen, Germany
AlAA FOURTH INTERNATIONAL
AEROSPACE PLANES CONFERENCE
1 - 4 DECEMBER 1992/0RLANDO, FL
For permission to copy or republish, contact the
American Institute of Aeronauticsand Astronautics
The Aerospace Center 370 L'Enfant Promenade, SW Washington, DC 20024-2518
DownloadedbyRussellHanniganonMay5,2016|http://arc.aiaa.org|DOI:10.2514/6.1992-5082

U
TRUE SPACE TRANSPORTATION:
THE KEY TO A NEW ERA IN SPACE OPERATIONS
Part I
Russell J. Hannigan
ESYS Ltd.
Guildford, Surrey, UK
The ending of the cold war, growing concern
about the Earth’s environmentand the increasing economic
and social problems facing all nations have conspired to
change the political rationale for funding space
programmes. Questionsare being asked abolrt the reiative
cost-eflectivenessof human spaceflight compared with less
expensive missions such as Earth observations. Asfor the
future human exploration of the solar system, the minimal
growth in today’s already over-burdened space budgets
provides little encouragementthat these and othergrandiose
ventures will be carried out in our life-time. Against this
background, this paper supports the proposition that our
future progress in space has the potential to be
fundamentally different and more positive than that which
we seem to bepresently headed toward. Forsuch a positive
future to emerge, ways to significantly reduce costs will
need to befound. It is conjectured that the introduction of
“truespace transportationsystems” - aerospace pianes - is
a manhtotyprerequisite in achieving thisgoaL In order to
provide an indication of the importance of transportation in
achieving signficant cost reductions in space operations,
this paper ik split into two separate parts. Part I (author:
R.Hannigan) focuses primarily on the impacts of aero-
space planes on low Earth orbit space operations. Part 11
(author:3. Sved) thengoes on to describe the importanceof
true space transportationsystems in thepossible economic
mining ofHe3from the lunarsuface.
RATIONALE FOR THE WORLD’S SPACE
PROGRAMMES
In recent years, the principal motivations for and driving
forces behind many space programmes have changed
irrevocably. It is generally accepted that the principal
requirement for both the US and former Soviet space
programmes stemmed from international rivalry. Space was
a highly demonstrative and visiblemethod for each nation to
prove their prowess at overcoming difficult technical
challenges. Many of the initial space activitiesborne out of
this rivalry have since evolved into extremely worthwhile
activities and important “tools” in the disciplines they
support, of which commercial communications, Earth
observation and weather satellites are the obvious examples.
Unmanned planetary exploration and space science are
similarly worthwhile simply because it would be irrational
not to undertake any exploration at all.
1
Human spaceflight has been very successful in attracting
high government Spending over the years. However, at the
same time, it has also struggled to find a single,
unambiguous, purely functional requirement to justify its
existence and high cost. Until recently, this hasn’t been a
particularly great concem because the political rivalry was
enough to sustain funding - if the USSR maintained an
active human spaceflight programme, then so would the
us.
The seeming failure of human spaceflight to find an
unambiguous purpose has prompted debate on the value of
this activity, compared with less expensive activitiessuch as
Earth observation by satellite. However, Earth observation,
telecommunications and other missions are “relatively”
inexpensive because such missions are not very
transportation intensive. Specifically:
rendezvouswith anotherobject in space isnot required,
* they do not have to be returned to Earth,
* they donot requireperiodic servicing, and, above all,
* human lifeis not put at risk.
Launching fully autonomous (unmanned) satellites on
expendabIe rockets is an important capability. But it cannot
disguise the fact that this type of approach to space access
severely limits the scope of missions that can be
undertaken. Specifically, it eliminates consideration of any
mission requiring repeated access to space facilities,such as
a space station or lunar base. Therefore, if space
organisations ever intend to do more in space than launch
single, fully selfcootained spacecraft,then the capabilityto
regularly access orbiting facilitieswith both crew and cargo
is mandatory. Virtually every single Earth-based activity
requiresrepeated and regular access. As this is the situation
on Earth, then it follows that cost-effective and regular
access to orbiting facilities is fundamental to open the door
to expandeduse of space.
The example of the recent re-boost of the Intelsat 6 satellite
demonstrates the value of the human analogue capability
coupled with the ability to repeatedly rendezvous with an
orbiting spacecraft. However, the actual cost of the mission
was at least twice the cost of building and launching a new
spacecraftfrom scratch. Yet, this doesn’t mean that on-orbit
servicing of spacecraft is not worthwhile or irrational. It
simply means that the cost of such a mission must be
severely reduced in order for it to stand up to economic
Coppight 0 1992by the American Institute of Aeronautics and Astronautics,Inc. All Rights Reserved
I

scrutiny. Reusing spacecraft holds the promise for
significanteconomic and operational gainspmvifed the cost
of undertaking the servicingmission is a fractionof the cost
of a new replacement.This is not the case today, but there is
no reason why it should always be this way.
accessing space becomes, the cheaper and easier space
activities will also become. Space transportation is just a
service and, like all other services, it should be as
inexpensive and “user-friendly”as possible to maximise its
utilisation.
L/
The current very high cost of launching people into space
distorts the value and potential of human spaceflight.
Clearly, it is difficult for human spaceflight to find an
unambiguous purpose while it remains very risky and many
times more expensive than “launching an Earth observation
satellite.” Hence, a rational approach for space programmes
will need to place drastic reductions in space transportation
costs, coupled with increased frequency, reliability and
safely, as the central objective. This has not, for a number
of reasons, been a high priority for the space-faringnations.
However. now that the political climate is changing to one
where there is increasingpressureto find justifiable reasons
for all space activities, it is incumbent on space
organisations to find less expensive, more frequent and safer
means to transport people and cargo to and from space. If
such an action is not taken, it is perhaps reasonable to
conclude that political support for human spaceflight will
wane as the pressure from other more rational and
unambiguous space and non-space programmes intcnsifies
in the current tight budget climate.
Today, it is not realistic to expect any nation to increase
The ImDacts of Current Launchers on SuaceActivities
Expendable launch vehicles (ELVs) such as the Delta 2 and
Ariane 4 have been very successfulin supportingthe space
programmes of the world. However, ELV capabilities are
very constraining when it comes to undertaking even
relatively simple space missions, and by far the greatest
constraint is launch costs. Typically, the dedicated launch
cost of a vehicle like Ariane 4 is in the region of $90-120
m. While competitive with other existing launch vehicles,
the high expense ensures that the total cost of the payload
will be at least equal to that of the launch. (Figure I) For
the most part, payload costs are equivalent to launch prices
in order to optimise total costs. In other words, any ‘‘user”
spending $100 m on transportationwill also spend at least
that amount on the space activity itself, thereby gaining the
maximum possible value from the expensive launch.
Exceptions exist, but, in general, for as long as launch costs
remain high, the number of space applicationswill remain
relatively limited and expensive. Also, while this situation
remains, the threshold for more commercial opportunities
will remain too high. W
space-speodingbeyond current l&ls fo; the existing type of
space programmes. Normally, such a situation would be
expected to paint a rather bleak picture for the future of
how space missions are undertaken, particularly those
involvinghuman spaceflight and orbital support operations.
Re-thinking space programmes should place the rationality
of the activity itself as the central requirement. It is not
enough to assume that governments will continue to fund
programmes for “political reasons” alone or they should
provide funding because of the nebulous promise of
obtaining technology spinoffs. Nor should space
organisations expect the public’s interest in space to come
spc‘-n cas
space. Yet, it also provides a real opportunityto “re-think” L.unrhCo.Lm
- W Y -
to their rescue. Rather, the requirement of the mission must
justify the cost. What this clearly means is that ways must
be found to significantly,if not dramatically, reduce the cost
,-*&

I
of space activitiesto levelsmore in line with the benefitsof
those activities. To achieve this, the number one priority is
- as it has always been on Earth -transportation.
THE NEED FOR A “RAILROAD TO SPACE”
Accessing space - gelting to and from low Earth orbit on a
frequent, safe and inexpensive basis - is the key to all future
space activities, large and small. Every activity undertaken
in space is fundamentally dependent on and intimately
influenced by the space transportation system that is used.
Therefore, it obviously follows that the cheaper and easier
Payload Costs Versus Launch Costs
Figure 1
One way to reduce launch costs is through mass-production.
However, such an approach is unlikely to realise “drastic”
reductions unless a great many (e.g. hundreds per year) of
vehicles are manufactured.Mass-production can reduce costs
of current launch systems somewhat. but it is not a
solution, and it will not drusticaNy cut dedicated launch
-

costs. With space activities such as lunar He3 recovery (Part
ID,cost reductions by a factor of at least 10 or even IO0 are
likely to be necessary. Critically also, launch costs are not
the sole problem that must be addressed. How the launcher
delivers a payload into space is, in many cases, just as
important, as will be discussedshortly.
Another approach is to reduce the cost per kilogramme
launched, as opposed to the dedicated launch cost. However,
the problem with this approach is that it inevitablyleads to
very large launch vehicle designs that continueto have high
dedicated launch costs. Ariane 5 is intended to reduce the
cost per kilogramme into GTO by a factor of about 33% and
into LEO by about 50%. However, its dedicatedlaunch cost
will still be about the same as an Ariane 4. As a result, the
total cost of the payloads riding Ariane 5 will be
approximately the same as those launched on Ariane 4.
Hence, the total investment tied up in an Ariane 5 launch
will be about the same as in an Ariane 4 launch - despitethe
apparently largedifferencein the costper kilogramme.
Judging space transportationpurely - or even primarily - on
the basis of cost per kilogramme can be extremely
misleading.The capabilitia of the launch vehicleitself have
a fundamental bearing on the type of space missions
undertaken. For instance, consider “reliability.” Because
expendable launchers are always thrown away after just one
mission, they are designed to minimise the cost of the
hardware that is discarded. As a consequence, virtually all
expendable rockets, and to some extent the Shuttle, are not
designed with the capability to safely abort a mission after
launch. Adding wings, exba engines, quadruplexredundancy
and thermal protection would add greatly to the cost of a
launcher that is “thrown away” after every mission. Hence,
ELVs will either succeed or fail - there is no possibility for
a second chance. By contrast, an airliner that loses an
engine, or a car that has a puncture, is rarely lost, but can
safely abort the voyage forrepairs.
The high cost and binary succeed/fail nature of current
launchers has a direct impact on how users conceive
missions and design payloads. Any users able to afford$100
m for the launch and $100 m worth of payload ($200 m in
total) will endeavour to utilise the minimum number of
expensive and potential& unreliable launches. As a result,
the trade-off will nearly always favourthe spacecraftdesigncr
cramming as much capability as possible onto a satellite
bus so as to get the most from a minimum number of
launchers. Alihough this leads to an expensive spacecraft
design, it is still cheaper than building several simpler and
less expensivesatellitesthat need more launches.
The intimate relationship between launchers and payloads is
summarised in Figure 2. In essence, the interactions are as
follows:
”
v
Impacts of Current Launchers
Figure 2
Expendable launchers are inherently expensive machines to
flybecause thehardware is discarded afterjustone flight.
*For this reason, it will be all but impossible -
economically and physically - to demonstrate that such
rockets can reliably and regularly launch payloads of
comparablevaluetotheELV hardware.
Therefore, the unproven reliability of the launcher will
tend to force a particular programme to maximise use of a
minimum number of vehicles.
Hence, not only will payloads need to be highly capable
and reliable, but simultaneously,they must also be highly
integrated and lightweight in construction to get the most
out of a few launches.
These conflicting requirements increase payload costs and,
as a result, constrain the number produced.
In addition, a small number of very expensive payloads
places higher reliability demands on the launcher because
of the added assurance needed to protect this high
investment.
This, in turn, further increases the launcher costs and
constrains(herate at which launches occur.
This vicious circle ensures that current launchers will
seldom fly more than a few times per year, and the payloads
they carry will be expensive and only a fewwill be built.
Other launch vehicle performance factors impact the way
space operations are undertaken, including flight rate,
susceptibility to launch delays, rendezvous and return
Capability, payload integration, and so on. The impacts of
each on space activities must be considered as fully
integrated with the rest. They also have differentimportance
depending on the mission being undertaken. For example,
communications and Earth observationsatellitescan tolerate
a launch date slip of many months - or even years - because
their missions are fully self-contained.
3
I

By contrast, supwing a space station can only be achieved
by a transportation system able to launch regularly, on-time,
rendezvouswith orbiting facilities, and return cargo and crew
to Earth. Likewise, activities requiring high rates of
research, such as in the disciplines of microgravity of life
sciences, would be best served by a low-cost, high flight-
rate launcher, with the demonstrated capability to launch on-
time and return experimentsto Earth.
The ability to launch regularly, on-time, rendezvous with
orbiting facilities, and return crew and cargo to Earth is
fundamentalto any space activity outside of launching one-
off autonomous missions such as Earth observation and
communications satellites. This is reflected by the fact that
the only space activity involving both deliberate assembly
in space and regular logistical support over many years is
the Mir space station. In this sense, a low cost per
kilogramme is meaningless to such space activities without
the criticalcapabilitiesneeded to supportthesemissions.
“User-Friendlv” m e Transportation Svstems
Expendable launch vehicles have served the space-faring
nations well. Nevertheless, it is reasonable to conclude that
these launch systems have an extremely adverse impact on
most current and envisaged space activities. If potential
users of space could dictate the capabilities of space
transportation systems, they would probably requcst the
following:
‘Lowest possiblededicated and per kilogramme launch cost,
*Modestpayload mass capability of up to 10 tomes,
*Frequent,regularly scheduled accessto space,
*Shortperiodof time fromorderto launch,
*Demonstrated high probabilityof mission success,
*Demonstrated capability to safely abort after in-flight
*Routinelyrendezvous, recover and returnpayloadsto Earth,
*Useof standardised interfacesincludingcontainerisation,
*Alternativelaunch vehicles forback-up,
*Lownoisdvibrational launch environment, and
*Multiple launch sites, preferably in easily accessible
failures,
locations.
No launch system today is capable of meeting any of these
requirements singularlyor simultaneously,with the obvious
exception of payload lift capability to orbit and, possibly,
back-up launch. Suffice it to say that this list of “user-
friendly” capabilities is very typical of most terrcstrial
transportation systems, including railroads, airliners and
automobiles. Indeed, no form of terrestrial transportation
utilises an expendable or “reassemblable”vehicle, with the
exception of some munition delivery systems. This might
seem an overly simplistic comparison - the complexity of
launching payloads into space far exceeds that of driving an
automobile,for example. Yet, thejunction - transportation -
is basically the same. All any user is interested in is how
well the transportation system achieves its function. Thus,
it is surmised that if transpottationto and from space was as
cheap and easy as using an airliner to transport people or
cargo between London and Orlando, the extent of space
activities would be profoundly different from what it is
‘4
today.
The idea of building the functionalequivalent of a “railroad
to space” - a true?space transportationsystem - is not new.
However, the technology needed to build such a true space
transportation system has lagged far behind the vision, and
in some space industry circles it is argued that the
technology is still inadequate.As a result, so the argument
goes, such vehicles will necessitate several decades of
research in the specifictechnologies of materials, structural
concepts, propulsion, computational methods. systems
integration and aerodynamics. The problem with such
arguments is that no organisation has yet attempted to build
a fully reusable single or twin-stage launch system
incorporating aircraft-likesupportabilityand maintainability
characteristics. Therefore, while the technology requirements
undoubtably present considerable risk, the lack of any
serious efforts to build such vehicles prohibits the
establishment of a referencepoint from which to judge that
risk. Furthermore, within the space industry today a wide
range of different solutions and vehicle designs are being
invcstigated. although a consensus of “what type of vehicle
should be built” is far from being reached.
The Potential of Aero-Space Plan@
Significant advances in technology within the last decade
have led a number of organisation to reassess the feasibility
of aero-space planes. Most notably, these effortsinclude:
*Inthe US there is the National Aero-Space Plane (NASP)
to build the X-30 and, at the other end of the spectrum, the
SDIO and McDonnell Douglas are building a suborbital
version of the Delta Clipper (DC-X).
.In Europe there is the German Hypersonic Technology
Programme (Siger), the British Aerospace/CIS Interim-
HOTOL/An-225, the French PREPHA advanced
propulsion programme, and the ESA Future European
SpaceTransportationInvestigation Programme (FESTIP).
*In the Commonwealth ojhdependent States there is the
MAKS vehicle designed to be air-launched from the An-
225 and the Russians reportedly were the firstto flight-test
a scramjet propulsion system in November 1991.
*InJapn, aero-space planes have played a major role in the -definitionof the futurenational spacepolicystrategy.

Despite different configurations, most programmes are
driven by the same goals. Whether the vehicletakes+ffs and
lands vertically or horizontally, uses air-breathing or pure
rocket propulsion, OF has one or two stages, virtually every
operational aero-space plane concept being studied is
conceived to achieve the followingbasic objectives:
launch mul retrieve 7-10tonnes ofpayload from LEO,
perform in the region 50missions every year for a fleet,
have an abort capabilityduring all phases of the mission,
profound way. Essentially, aer+space planes shouldhave the
ability to safely abort a mission at practically any point and
return to Earth. Relativelyminor problems caused by “rags
being left in fuel lines” or “contaminates stuck in
turbopumps” might lead to an engine shut-down, but
probably not the entire loss of the vehicle. In addition, the
simple fact that a new vehicle does not have to be carefully
manufactured and integrated for each mission reduces the
potential of “inducing”additionalproblems.
The inherent testability of aero-space planes should also
allow operators to deliberately cause failures in flisht in
These capabilities combined are radically different from all order to learn how to safelyrecover these vehiclesin various
launch systems today, but are more in line with the user kinds of contingency situations. As a result, aero-space
requirements listed previously. It is important to appreciate planes should be able to demonstrate that they can be safely
that these basic capabilities are inherent charnctenktics of recovered during the course of an incremental flight test
any true transportation system - specifically, vehicles that programme, and long before entering service. This is
areboth reusableandincrementallytestable. undoubtably the most important aspect of aeroqace planes,
just as it is with airliner and, for that matter, all other true
Full reusabiliy means that it is not necessary to build, transportation systems. It is a capability likely to have
stack, inspect and check-out a brand new vehicle before profound ramificatioosFor all space activities in the future,
every single mission. By itself, full reusability does not simply because users will not necessarily lose their
necessarily lower costs - an aero-space plane that flies three expensive payloads after an in-flight failure - as is the case
or four times per year might be just as expensive and today with ELVs.
unreliable to use as an expendable rocket. An equal feature
of aero-spaceplanes is that they can be flight-tested in an By the time aero-space planes enter operational Senice,they
incremental, step-by-step manner, just as aircraft, will have flown more flights (includingsuborbital) in their
automobiles, trains and other forms of terrestrial test and qualification programmes than most expendable
transportation routinelyundergo “shakedown”testing before launch systems will fly opemtbnal!v in one or two decades
being used operationally. The new Boeing 777 is an or, indeed, in their life-times. Should aero-space planes be
excellent example in this regard. Before this aircraft is ever feasible, they would be able to demonstrate their reliability,
allowed to cany fare-paying passengers or cargo, nine 777s abortability, and capability to make regularly-scheduled
will be flight-tested, three of which will each make 1,000 flights long beforecarryinga payload.
flights. By contrast, Ariane 5 will make just two
“qualification” flights that will either go to orbit or fail. Realising such true space transportation systems presents
Also, neither the US nor the former Soviet Space Shuttle enormous challenges,and it is by no means clear whether it
concepts can be incrementallytested, and this is one of the is indeed feasible. Yet, if such vehicles could be built, it is
fundamental technical reasons why both vehicles will reasonable to expect that the way in which space missions
always be expensive to use, fly infrequently and be launched are conducted would also change - and change profoundly.
only afterextensiveand labour-intensivechecking. Intuitively, the development of a fundamentally improved
means of accessing space should enable an equally
The first flight of an aero-space plane will not go fundamental improvement in how space activities are
hypersonic. Indeed, the undercarriageprobably won’t even be actually performed, ranging from economic savings in
pulled up. Eventually, however, after several dozen test launch costs, opportunitiesto re-optimisespacecraftdesigns
flights, an aero-spaceplane may attempt an orbital mission. in order to save costs and simplib operations, and making
The incremental testing approach will allow operators to new missions possible that were previously uneconomic or
understand the individual characteristics and handling simply impractical. The impacts of aero-space plane-type
qualities of the vehicle long before an orbital mission is space transportation is the subject of the next section.
attempted. This is vital to develop the levels of confidence
needed to reduce servicing activities in between missions. IMPACTS OF TRUE SPACE
As a result, launch rates will increase, delays minimised, TRANSPORTATION ON SPACE ACTIVITIES
and morethan anythingelse,launch costsreduced.
One of the beneficialby-products of macro-projects such as
Together, full reusability and incremental testability also lunar He3 recovery or Solar Power Satellites (SPSs)is that
have the potential to improve safety and reliability in a their various elements could involve and impact nearly all
have a dedicatedlaunch cost of $10-20m per flight.’
’Geneally. cosb include life-cycle cost recovev over 20-25 years Other Of the space industry* and vise versa.
5
I

Observation satellites would be needed for lunar surveying,
as would communications platforms, space stations and
orbital transfer vehicles. Most fundamental of all, they
would ensure the development of a cost-effective and robust
space transportation system and space infrastructure
available for useby many other other applications.
But this vision for the future of space created by the
potential of He3 and SPSs remains just that: a vision.
Although it is never too early to rigorously explore their
potential, it might also be considered too early to pin all
hopes on these grandiose space applications. Theref0re.h
charting the course of the World’s future in space,
diversification is clearly important. Ideally, these
programmes should be rational and justifiable in their own
right, but they should also make important contributionsto
future ambitious space activities.
The key link is the Earth-to-orbit space transportation
system. If the objective of future space efforts is just to
launch a relatively small number of “one-shot”autonomous
satellites, then current launch systems are adequate. For
missions needing routine support and servicing of spacecraft
in orbit, aero-space planes will almost certainly be
mandatory. The only exceptions are very limited capability
space stationslike Mir.
Yet, even autonomous satellite missions would benefit
significantly from the availability of aero-space plane
launchers. Consider the example shown in Figure 3 of the
economics of launching a typical 2.5 tonne commercial
communications satellite on today’s mkets compared with
Although this is a relatively simplistic example, the
economic benefits are apparent. The beneficial impacts of
am-space plane launchers would alsoextend beyond simple
monitory savings.For example:
.The demonstrated reliability of such a launcher, coupled
with its ability to safely abort a mission in flight. would
positively impact insurancepremiums.
“
*The demonstrated ability of aero-space planes to launch at
much shorter notice due to their higher availability (flight
rate) would avoid the lengthy launch delays often observed
today. It would also provide the opportunity to decrease the
total time required to deploy “constellations” of LEO
comsats, such asthe proposed Iridium network of medium-
sized satellites.
.The ability to use standard payload containers-just as with
aircraft, trains and other forms of shipping - would
disentangle launch vehicle processing from the payload
processing, as well as significantlyspeed up final payload-
to-launcher integration.
-Potentially, a significantreduction of both the&dW and
unit mass &e. per kilogramme) launch costs would allow
a relaxation of the current pfactise of designing spacecraft
to minimise mass. Ultimately, this would allow the
spacecraft to grow in a way that reduces its cost because
simplerand more robust construction methods can be used.
The last of these points is perhaps the most important.
Only a simultaneous reduction in dedicated launch mt and
W
launching oneon an aero-spaceplane
Sa-a
Satellitecost
Current Launch System
Launch cost (e.g. sharedAriane 44L)
Insurance @ 18%of investment cost
Hence, total launchcosts
Aero-Soace Plane
Launch cost’
Insurance @ 10%of investment cost
Upper stage cost (e.g. existingPAM-D2)
Hence, total launchcosts
$60 m
$50 m
$20 m
$70 m
$15 m
$9 m
$15 m
$39 m
Total Savings $31 m
Comsat Launch Economics
Figure 3
‘Based very approximately on the life-cycle cost estimates
generated by major aero-space plane programmes.
the &st per kilogramme would enable significantreductions
in the cost of the current generation of comsat designs. This
is simply because a significantly lower investment in
launch costs would mean that spacecraft designers would not
need to focus so much effort on minimising or optimising
the total spacecraft mass.
Ultimately, should aero-space planes be feasible, they
would dominate the commercial coma1 launch market,
provide the opportunity for more cost-eflective satellite
designs and enable new mission opportwrities because the
start-up cost threshold and risk would be significant&
lower.
This type of approach can be applied to all other spacecraft
missions, such as scientificsatellitesand space stations,and
each mission will liberate varying degrees of beneficial
impacts. Consider Earth observation satellites. Currently,
the economic trade-off makes it appear cheaper to launch a
single, large satellite on one rocket than to build a series of
more modest spacecraft and launch them on several rockets.
In addition, such satellites are not built to be serviced on
orbit because a servicing capability simply does not exist.
The E A POEM-1 satellite (as it was originally conceived)
-
6

followed this line of thinking to minimise total programme
costs. The obvious problem is that it leads to an expensive
satellite which takes many years to complete. POEM-I is
budgeted at about $1.5 billion and will be launched after
nearly a decade of work. More profoundly perhaps, it ties up
a high investment in a launch system that has no abort
capability. Thus, if a launch were to fail, it might be many
years before a new satellite could be constructed and
launched. Likewise, the same is true if the spacecraft fails
once in space. Consequently, considerable effort will be
expended to make sure, as far as possible, that the launcher,
spacecraft and the array of sophisticated instruments will
function properly on the very first attempt. This “one
complex, multidisciplinary satellite per launcher” strategy
nevertheless is still cheaper overall with the current
generation of launch systems. However, the investment put
at risk is far greater.
Aero-space plane launchers hold the potential of reversing
this trade-uff for the same reasons outlined for the comsat
mission, with the additional benefit that if the satellite
suffereda failure in space,it could be repaired or returned to
Earth. For example, instead of one large, mass-optimised
satellite carrying a multi-disciplinary payload suite, each
instrument could be flown on a single, standard, robust
platform and launched into an optimum, uncompromised
orbit for its mission. This would reduce total programme
costs and risks. Importantly also, it would ensure that
individual Earth observation instruments would be launched
when they were ready, unlike today where every instrument
must remain on the ground until all areready for launch.
Ultimate&, the Earth observation community benefits
because data can be received more quick&, with continuity.
and at lower cost. This “one-instrument per standard
platfom per launch” strategy m y also reduce cos& to the
point where a true, fur& self;rupporting commercial Fnrth
observation indushy can emerge.
Communications and Earth observation satellites are
probably the easiest space programmes to rationalise
presently because their benefitsfar outweigh their cost, even
given today’s expensive and constraining launch systems.
However, even here significant improvementscould be made
given a fundamental improvement in space transportation,
as discussed above. With this perspective in mind, the
following subsections are intended to provide a brief
overview of possible options for a diverse range of space
activities. The basic aim is to demonstrate that space
programmes which appear difficult to rationalise today
because of their high cost, may become less expensive and,
therefore, easier to justify following the introduction of a
fundamentally improved meansof accessingspace.
W
W
TheImoortanceof TechnolowDemonstrah
The space industry is often recognised, and wen partially
justified, for its role in pushing new technology. However,
even though the initial pace of technology innovation and
development work is usually quite rapid, conversely its
implementation is invariably very slow. The reason for this
is that initial development work can be paformed relatively
inexpensively (typically. about 510% of total programme
costs) as it occurs in easily accessibleEarth-based facilities.
By contrast, in order to subsequently prove a new
technology in space, the cost of performing such a test is
very high because of the high cost of space transportation.
Further, the limited launch opportunities invariably force
long schedules before any demonstration can be made. The
result is the slow implementation of new technology into
practical applications.
For the most part, the space industry must rely on
exhaustive ground development work to validate a new
technology. This is an expensive and time-consuming
process, especially as the first time any new technology is
launched it usually is on a highly expensive test or even
operational spacecraft. A pertinent example are the
European-built Hubble Space Telescope solar mays. Hubble
required the development of unique solar mys that had to
be retractable so that the telescope could be returned to
Earth. The arrays also had to be lightweight in design.
Therefore, a unique solar array system was devised and
exhaustively tested on the ground. Unfortunately, once
launched it was found that these mays “flexed” far more
quickly than ground simulations had predicted, causing
significant disruption to observations requiring sub-
arcsecondpointingprecision.
This type of problem could have been avoided had the
opportunio existed to test-flya development model in space
long before the final telescope was built. This is impossible
today because of the very high cost and limited launch
opportunities on the Shuttle. However, the introduction of
aero-space planes would likely reverse this situation. For
example, a development pfogramme could build a breadboard
version of the array which would be bolted to a standard
structure (e.& MPESS, SPAS etc.), and then launched on a
regularly-scheduled aero-space plane mission. After a few
hours or days in space the demonstration package would be
returned to Earth. (Figure 4) Technology demonstrations
have already occurred on a number of Shuttle flights. The
deployment of a 35 metre-long solar may from Discovery
in 1984 is a prominent example. However, the Shuttle’s
very high cost and low flight-ratesimply precludes its more
regular utilisationin this important role.
Ideally, in order to minimise costs such a technology
demonstration mission should share payload capacity with
other experiments. Sharing capacity is a difficult and
7
I

complex task today. However, if aero-space planes can
demomtrate the ability to launch regularly, frequently and
on-time, then users can quickly become attuned to such
launch opportunities. This process would also be eased
considerablyby theuseof containerid payloads.
Routine Technology Demonstrations in Space
Figure 4
This type of scenario is radically different compared with the
current practise, but it is very much in line with how non-
space technologies are developed on Earth. Technology
demonstration in space is considered vital to future space
activities. especially those involving support operations.
Recognising and quantifying the value of technology
demonstrations today is very difficult simply because of the
near-inability to performthem.
The current inability to perform regular technology
demonstration also makes it difficultto accurately judge the
relative difficulty of certain space activities. For example,
because developing and implementing space technology is
expensive under present circumstances. it can lull some
organisations into believing that space programmes are
inherently expensive by nature. At another extreme, if it is
impossibleto test a new piece of technology in space, it can
lead some to the conclusion that certain activities are easier
than they actually are, simply because there is little or no
comparable experience for reference. This latter point is
particularly true for those space missions requiringasembly
and support in space.
Ultimately, the ability to routinely, repeatedly and cost-
effectively perform technology demonstrations as early as
possible on any new space programme will be of
considerablebenefit because it can reduce the risk and cost of
the finalprogramme objective.
-p in in
The success of commercial communications satellitesis due
largely to the fact that, once the satellite is launched, the
a
nature of the business does not require the exchange of
“products” between space and the ground, other than
electromagnetic radiation - i.e., comsats are not
transportation intensive. However, if communications
satellites required just one support mission (e.g. for
servicing) every year, there would not be a commercial
comsat industrytoday. It is precisely for this reason that the
commercial manufacture of products in space has failed to
“take off.” Opportunitiesto return products made in space
are few and far between, and when they do arise, they are
either restrictedto very small payload masses, or the cost to
launch and return payloads is excessivelyexpensive.
Today, just to launch and return one kilogramme of
anything costs about $25.000 on the Shuttle, and more than
$250,000 using a capsule system (e.g. the US COMET).
These figures become more meaningful when it is realised
that transportationcosts can consumejust 1-570of the total
cost of a final commercial product. A large fraction of the
mass launched is the actual processing hardware. Ovahead
and other ground costs must also be factored in. As a result.
to profitably manufacture something in space, each
kilogramme of final product would need to sell for between
$0.5 million (very optimistically) to as much as $25
million (COMET). This is not realistic, especially as these
figures assume limited or zero precursor research. For as
long as this remains the economic and operationalsituation,
commercial materials processing in space cannot even be
considered asa potential - if simple will not happen.
In the early 1980’s,a Center forSpace Policy report in 1984
claimed that by the year 2000, the m n u l gross income of
all commercial space activities could be as high as $50
billion. Notably, the $42 billion of this revenue was
anticipated to come from products manufactured in space.
Today, most analysts believe the revenues from commercial
materiaIs processing research is on the order of a few
millions of dollars, with the “products” being limited to a
small number of protein crystals and other items grown in
space.This is despitethe large government investment made
in a number of Spacelab flights and other Shuttle
experimentsoverthe last decade.
Yet, a large number of high-value, modest-mass products -
pharmaceuticals and semiccmductors - rea& wouu benefit
from the almost megravity and practically-perfect vacuum
of space. If it were possible to create a microgravity
environment in a laboratory on Earth, it would be used
continuously, simply because access to it would be very
inexpensive, probably even taken for granted. Although
building an Earth-based micrograviry laboratory w’ll always
remain firmlyin the realm of science fiction, a functionally-
equivalent (inexpensive and easily accessible) capability in
space will have to exist before any commercial space
manufacturing can ever become a reality. Therefore,
transportation costs to and from space may have to drop by
“
L,
-

a revolutionary amount. m a p s by more than a factor of
100, with launches occurring almost as frequently as
airliners.
Whether fully self-supportingcommercial manufacturing in
space will be possible, even with the availability of aero-
space plane launchers, is impossible to judge. However,
frequent and low-cost launch opportunities would at least
enable a higher volume of research to be performed in a far
more cost-effective manner than presently. A typical
experiment could be performed much in the same way as
described for technology demonstrations, i.e., bolted to a
SPAS-like structure and launched on a regularly scheduled
aero-space plane mission.
The lesson to be drawn from the world‘s limited experience
with space manufacturing is that making products in space
is possible and a very realistic prospect. However, its
potential can only be commercially realised once the cost of
accessing space drops dramatically. Space manufacturing is
not absurd, it’s just that current launch costs make it
appear absurd.
%we Station Develooment and Utilisation
It was hoped that Space Station Freedom would be a
quantum improvement compared with MU, and the intention
was to have a multi-purpose facility whose services would
range from a base for commercial materials processing to a
way-station for manned missions to the Moon and Mars.
Unfortunately, Shuttle-related technical problems and
budgetary realities have pruned back the capabilities of
fiedom to the point where, at best, it is a facility for basic
lifesciencesand othermicrogravityresearch.
Assuming that Freedom is successfully completed, it is
interesting to look briefly at how aero-space planes would
impact the economics of the annual logistics operations
compared with the Shuttle. (Figure5)
W
Soace Shuttle AemSpace Plane
Flights/year 5(cargo/crew) 10 cargo flightsonly
5crew flights
Payload cap. 18tonnes 7 tonnes cargo only
6aew (+3tonnes)
Cost per flight $500 m $15m
If aero-space planes came even close to meeting their
dedicated launch costs, then the illustrated savingswould be
on the order of lwo billion dollars peryear. Even if aero-
space plane launch costs were three time higher (Le. $45m
per flight), the annual savings would still be about $2 m.
The staggering difference in the costs can make aero-space
planes look somewhat unbelievable. It could be argued that
this really seems “toogood to be true.’’ This may indeed be
proven to be the case.However, a more likely answer is that
it shouldn’I cost two or three billion dollars a year to bad
90 tonnes worth of food, water, clothes, spare parts and
experiments to and from orbit, as in the case of the Shuttle
andFreedom.
Another way to read this example is that aero-space planes
could pay for themselves within a few years purely on the
savings of not using the Shuttle to support’Freedom. In
addition, for vehicles like the Delta Clipper or the Interim-
HOTOL, the 15flightsper year estimatedin Figure 6 would
probably be adequate to justify the high cost of their
development. Viewed rationally and logically, this would
make the case for aero-space planes very compelling. At the
very minimum there is sufficient motivation to investigate
whether aero-spaceplanes can really be built and achieve the
promised operationalperformance and costs.
In addition, to launch cost savings, aero-spaceplanes would
have other beneficial impacts on space stations. To help
explain these impacts, consider the assembly of Freedom
using the Shuttle. Freedom will require about 7 Shuttle
flights each year over 4 years for assembly and logistics.
However, the Shuttle is currently limited to a maximum of
8 flights per year because of its high complexity and high
operating costs. Therefore, during Freedom assembly there
is a maximum Shuttle capacity reserve of just one mission
per year. (Presumably, this one flight will be dedicated to
some other non-Freedom mission.) While mathematically
this scenario appears feasible, operationally it is not clear
that this is the case. What happens if some time during
assembly, one of the modules does not attach properly?
What happens if a failure occurs on the partially completed
station that necessitates in-orbit replacement of major
components? Unfortunately, it is not feasible to “just”
launch a Shuttle on demand. In addition, as there is little
reserve Shuttle capacity, any repair mission will bump
future payloads, fore-stalling the eventual completion date.
Further, the Shuttle may not be able to respond quickly
enough if the Station suffers a major failure requiring
immediaterepair.
Annual cost $2500 m $225 m Station designers can attempt to minimise this situation
through careful and thorough design. However, this is me of
the principal reasons for the high costflong schedule of
Freedom. Moreover, it is not clear whether it is possible lo
catch all the problems and also accommodate every
W
Economics of Freedom’s Annual Support Costs
Figure 5
9
I

eventuality no matter how much money is spent. The US
has never built anything in space that has required
consecutive launches. The CIS, by contrast, has built and
supported MU for a number of years. However, significant
problems occurred when attempts were made to dock the
fist two relatively simple modules.
The above kinds of problems can be reduced with the
availability of a space transportation system that has the
demonstrated ability to launch frequently, reliably, on-
demand and at low cost. As with comsats and Earth
observation satellites. the beneficial impacts of aero-space
planes on space stationssuch as Freedom go beyond simple
launch cost savings. Therefore, if launch costs per
kilogramme can be significantly reduced and launch rates
increased, this may allow space stationsto :
be less expensive,
be developedmore easily,
use simpler, heavier and more robust technology,
* be deployedmorerapidly,
facilitateroutine logisticalsupport, and
* allowconstantup-grades and changes.
Aerc-space plane-launched space stations would, initially at
least, be smaller than Freedom because of the smaller
payload capability of aero-space planes compared to the
Shuttle. However, this is considered mcfe of an advantage
than a draw-back. Building a small space station would,
among other benefits, allow experienceto be gained in the
basic areas of logistics support and maintenance of
permanently-manned facilities.It would also allow a better
understanding of the problems associated with on-orbit
conshuction and integration. For example, large expendable
boosters would be able to launch the relatively inexpcnsive
“shells” of the large extension modules. Aero-space planes
would then be used to gradually outfit these modules with
the “expensive” internal equipment. This is something
practically unthinkable today, hut only because limited and
highly expensive space access prohibits the kind of
experience needed to determine what it really means to live
and work in space.
N- Di
Forthe next several decades, Earth-based nuclear fission is a
viable and considerably less expensive alternative to both
He3 fusion reactors and/or SPS constellations. One of the
fundamental problems with nuclear fission is that various
grades of highly toxic by-products are produced. This
presents both the economic and social problems of how to
safely and efficientlystore this waste for very long pcricds
of time, perhaps for many centuries. There are terrestrial
solutions, such as encasing the waste in glass-like material
and burying it many kilometres into the Earth’s crust or
be supportedas and when problems occur,
deeper, but tnere remain public concerns that while any
waste is on Earth, it is a threat to society. This concern is
almost at a standstill.
The possibility of disposing of nuclear waste in space
presents a solution that could be publicly acceptable,
demonstrate an unambiguous use for space, and, potentially,
also offer lucrative commercial opportunities. For example,
highly toxic nuclear waste ; produced in annual quantities
on the order of 50 kilograms for every gigawatt of energy
produced, giving an annual total of several “tens” of tonnes
of waste. Therefore, disposing of nuclear waste might be
economically worthwhile because the worldwide nuclear
industry generates revenues of 100-200 BAU. Even at
current launch prices, theoretically only 1-2% would be
added to the cost of electricityto the consumer.
Economically, the case for nuclear waste disposal appears
interesting. Opera&ional&,however, there are many serious
problems. With current launch systems not only are costs
high, but the binary succeed/fail nature of these rockets
would practically guarantee that failures would occur at
some point. Therefore, if nuclear waste was launched on
expendable rockets, it would have to be enclosed in a
capsule-likestructure that could withstand a launch pad or
in-flight explosion, ballistic re-entry through the
atmosphere and high-speed impact with the ocean and then
survive for many decadedcenturies at the bottom of the
ocean. Although such a capsule is feasible (eg. the RTGs
used on Galileo, Ulysses, etc.) the obvious conclusion to
this logic path is that it would be perfectly safe to leavethe
nuclear waste on Earth in the fist place and avoid the high
cost of launching it into space. (Broadly similar arguments
can be made against an alternative such as the use of
electromagnetic rail guns to fire encapsulated nuclear waste
dircctly into space.)
Using Current launchersis technically feasible,hut they are
operationally compromised by the “must work” nature of
the launch system involved - a potentially socially
unacceptable prospect. Considerable protests and legal
activity were exerted in order to stop the Shuttlelaunches of
the Galileo and Ulysses probes because they each carried a
few kilograms of Plutonium. The reason for these protests
was the demonstrated knowledge that Shuttlescanfail. For
global nuclear waste disposal, the number of required
launchcs would need to be far higher (e.g. 5-10 launches per
year), with each mission carrying 10 or 100 times as much
waste asthe RTGscurrentlyused on spacecraft.
On Earth by contrast, highly toxic nuclear waste is
routinely transported on trains, shipsand aircraftwith only a
few incidents. The fundamental difference between these
transportation systems and those describedabove, is that the
reliability of individual terrestrial vehicles can be
so great that the construction of new nuclear reactors is i/
-i
10

demonstrated long before MYnuclea; waste is carried, and if
-iproblem does occur,the failure can be tolerated or a safe
u b o r t performed. These characteristic<are identical to those
sought afterby aero-spaceplane devehpers. As a result, it is
possible to envisage a scenario whex aero-space planes
could be used to dispose of nuclear v aste, but only ufer
they accumulate a large number of succ:ssfulmissions (e.g.
loo’s), and demonstrate a range of safe aborts. This would
help bring the public confidence kvel in the space
transportationsystem close to that of the trust put in trains,
shipsand planes.
A notional nuclear waste disposal operction could, for
example, involvethe following sequenceofcvents:
*Encapsulation of the waste within its own Fhielding (e.g.
glass) to allow easierground handling,
*The waste is then placed in a capsule that can survive a
launch failure and parachute to Earth (using a high level of
parachuteredundancy),
*The capsule is placed in a payload container and then
launchedon aregularly-scheduled aero-spaceplane flight,
.In LEO, the am-space plane performs a rendezvous with
an orbitaltransfervehicle,
*The waste is then automatically extracted from the capsule
and secured to thetransfervehicle,
*Once enough waste is accumulated, the transfer vehicle
fires its engine lo push the waste into a higher Earth orbit,
”a heliocentric orbit or an orbital path bringing it close to
the Sun,
*If there any problems occur during the on-orbit activity,
either the aero-spaceplane returns the waste back to Earth
or a second aero-space plane launches immediately Le.,
within days).
As there is always a possibility of a catastrophic failure -
although significantly less than with expendable rockets -
the capsule would probably still need to be constructcd so
that it could survive a ballistic crash back to Earth.
However, in this scenario the capsule could be relatively
sophisticated with high levels of redundancy (c.g. in
parachute deployment, location determination, attitude
control, etc.). Such a system would necessarily be rather
expensive. Although, using a recoverable launch system
allows the capsule to be reused many times, amortisingthe
cost. By contrast, it would be costly to throw such a
complex capsule away after launch on an expendable
vehicle, asdiscussed earlier.
If less than one percent of today’s worldwide nuclear power
industry annual revenues was spent on disposal of nuclear
waste (i.e. about 1 BAU) then this could lead to a very
lucrative contract that would pay for a large fraction ofthe
-cost of developing the aero-space plane fleet in the first
place. Importantly also, nuclear disposal operations would
add significantly to the demand for aero-space plane launch
services and, as a direct consequences. further reduce launch
costs to the benefit of all other space activities.
Human solar Svstem Exwloration
Pesident George Bush’s call in July 1989to send astronauts
“back to the Moon” followed by a “manned mission to
Mars” has been unable to capture the support of the US
Congress and people. For the Fiscal 1992 budget, for
example, only $5 million was approved for research on
NASA’s Space Exploration Initiative (SEI) effort.
Furthermore, in May 1992, $1.5 million of this
appropriation was “rescinded in a measure to cut federal
spending. Given the state of the US economy and NASA’s
anticipated near-zero growth for the rest of the decade, the
chances of sending humans to the Moon and Mars appear
slim in the extreme.
The problem with SEI-type activities is that they are both
very expensive and lack any real purpose other than pure
exploration and science. On Earth, by contrast, the
motivation behind “large-scale”exploration has always been
to discover new opportunitiesfor development and growth.
Columbus’s voyage to the New World is a very well-
documented human exploration mission, and analogies with
it are often made to justify SEI-type programmes. However,
the incenlive for Columbus undertaking this mission was to
open up a new spice trade route to and from India. If SEI-
type activities were seen as promising the same type of
commerce, then their justification might be easier. This is
precisely what supporters ofHe3 recovery and SPS systems
hope will be the case.
It is true that explorationon Earth is sometimes undertaken
for no other purpose than “because it is there,” such as
climbing a mountain or walking to the North Pole. Again,
similar analogies are often made lo support SEI-type
activities. However, cost and technical difficulties are the
major stumbling blocks - it didn’t cost “billions of dollars’’
for Sir Edmund Hilary to climb Everest. for example.
Obviously, climbing a mountain is inherently easier than
going to the Moon, but the one fundamental difference
between the two is that the mountain climber does not have
to create the infrastructure needed to reach the mountain.
Airliners, trains, cars, and ships are all readily and
commercially available, as are hotels, power stations,and so
on. By contrast, a mission to the Moon will need to not
only worry about the cost and danger of the exploration
aspects of the mission but uko creating the infrastructureto
get there in the first place. If heavy-lift rockets are used as
the sole means of accessing the Moon or Mars,then the
situation is compounded because the entire mission,
infrastructure and safety of the crew, is held hostage to a
launcher that can neither be flight-tested beforehand nor
perform safe aborts. If the launcher fails, the so-called
“infrastructure”is destroyed. This is precisely why when the

US Apollo programme was completed, there was nothing
left in space to show for it. Pursuing the same approach
today, would ultimately lead to the samezero-sum result.
It is for these reasons. more than perhaps any other, that
SEI-type activities are fundamentally so expensive under
present circumstances. Human exploration of the solar
system is, despite its current state, a very worthwhile
activity provided the cost can be significantly reduced. A
cost-effectiveand robust space infrastructureis the highest
priority to drastically reducing costs. Ideally also, the
promise of economicreward and growth (e.g. He3 or SPSs),
may be needed as at least a puhd incentive befon? human
voyages to the Moon and Mars become realistic and
worthwhile propositions.
CONCLUSIONS
An opportunity exists today to capitalise on the World’s
inveshnent in space in order to create a new direction for
space programmes. The rationale for these programmes
needs to focus stmngly, perhaps exclusively, on ensuring
that the benefits are worthy of the cost. Future space
programmes would consist of a diverse mixture of
traditional satellites and robust human spaceflight
infrastructure elements, conceived and operated in a cost-
effectivemanner.
To achieve many of the hoped-for benefits of space,
emphasis must be placed on finding ways to drastically
reduce costs, and especially operational costs. Thcrefore,
space strategistsmust dispel the current ingrained myth that
space is always going to be an inherently expcnsive and
difficult activity so that they may understand the extent to
which costscan be reduced.
It must be recognised that accessing space underpins all
efforts to drastically reducing costs of space operations.
Without the equivalentof a “railroad to space,” it is difficult
to envisage a space programme that can evolve much
beyond current efforts. Certainly, the construction OF a
robust space infrastructure mandates a fundamentally
improved means of accessing space. Already, there are many
programmes and studies worldwide investigating the
possibility of building true space transportation systems.
These efforts should be encouraged, expanded and brought to
the fore-front of the ”new thinking” in space. Moreover,
there is considerableopportunityto combine the tcchnology
and talents of nations worldwide to realise such a capability
more quickly and at lower cost than any nation could
achieve alone.
The space programmes of the next decades presents a real
opportunity to lay the foundationsof the much-needed space
infrastructure. Building aero-space planes is mandatory as
the fiat step, and can lead to significant cost reductions in
the day-to-day space activities,as well as allow missions to
be undhaken at lower cost and more routinely, and enable
new mission opportunities by lowering start-up economic
thresholds. Once the Earth-to-LEO transportation
infrastructureis in place, the in-orbit infrastructurecan start
to evolve in support of commercial and civil missions
ranging from communications and Earth observation
satellitesto materialsprocessing and nuclearwaste disposal.
Ideally, the space infrastructure should be justifiable on the
missions it supports, including commercially-driven
operations.Should this occur. it is conceivable to envisage a
scenariowhere a mission to recover He3 from the Moon, for
example, would take advantage of the existing space
infrastructure already in place. Such an approach would
dramatically reduce the cost of an He3 recovery programme,
as well as other objectives such as exploring the solar
systcm. The experience in building the space infrastructure
would reduce significantly the risk of such programmes
because human spaceflight would become a very well-
known and very well-understood subject.
d
Acknowledgement. v
The authorwould like to thank John Sved of DASMRNO
for his support in writing this paper.
References
This paper was derived, in part, from a report commissioned
by EUROSPACE, Paris entitled “Europe’s Future in a
Worldwide Space Programme.” In addition, this paper was
based on material from the author’s forthcoming book
“Spaceflight in the Era of Aero-Space Planes,” to be
published in Spring 1993 by Krieger Book Company,
Flwida.
12

TRUESPACETRANSPORTATION:
THE KEY TO A NEW ERA IN SPACE OPERATIONS
Part II
John Sved*
New Missions and Operations Department
ERN0 Raumfaluttechnik GmbH
Bremen. Germany
The foreseeable market for cis-lunar space
transporation capable of supporting industrial operations
on the Moon is described. Unattractive recurring
operations costs of partially reusable multi-stage
transportation infrastructure concepts forces an
eMrmnat. ion of the potential of a vertical take-off and
landing single stage "Lunar Ferry" derived from current
reusable single stage rocket vehicle developments. The
velocity change quirements for a VTOL SSTO vehicle
match well with lunar landing and rehlm budgets. The
infrastructure is simplified to refuelling stations in
equatorial Low Earth Orbit that offer frequent departure
and return windows. The PROFAC concept is
considered as an alternative to multiple fuel tanker flights
per lunar mission. The availabilityof lunar liquid oxlgeu,
and hydrogen as a Helium 3 mining by-product, permits
v multiple increases of the flight rate for a fmed "Lunar
Ferry" fleet. The 'Zunar Ferry aerospace plane returns
to its Eanh surface spaceport after offloading propellant
exported from the lunar spaceport and undergoes a rapid
m - m u n d . The inherent resiliance of the VTOL SSTO
derived cis-lunar transport infrastructure and its
remarkably low COst per mission potential is indicated for
consideration by aerospace industry strategists. This
paper forms Part I1 of a discussion of true space
transportation systems. Part I (author R. J. Hannigan)
considers the importance of aero-space planes for access
to and utilization of low Eanh orbit.
Most well known is the concept of Solar Power Satellites
that collect the solar visual, near ultraviolet or infrared
flu and convert it to a beam of energy thatis transmitted
toreceiver facilitieson the Earth's surface. A variationof
this concept places the solar power facility on the surface
of the Moon. Both of these concepts are characterized by
very large quantitiesof constructionmaterial to built large
I
collection area arrays.
Another energy industry concept is based on the
availability of the isotope Helium 3 in amounts and
concentrations that may economically support a
terrestrial nuclear fusion power industry for thousands of
years. Fusion power is regarded as tbe foreseeable long
term energy source that is usable anywbere in the solar
system and is conventional in terms of integration in
existing infrastructures. The advantage of Helium 3
'brning" with heavy Hydrogen Deuterium is that the
reaction ash consists of Helium 4 and protons. Direct
conversion of the proton energy into electricity offers
some 70% energyrecovery. Theprotons arecontrolledby
magnetic fields and the neutron flux emissions from
secondary reactions is so reduced that the commercial life
of such a Helium 3reactor is estimated at some 40 years.
The already demonstrated reaction of Deuterium and
Tritium Hydrogen isotopes produces neutrons which
would render a reactor unwable after a few years of
continuous operations; thus requiring an uneconomic
replacement of the s ~ a l l e dinner toriod - tokomak wall2
A commercial market that requires space transportation
services is the electric power industry on Earth.
Environmental problems associated with the
consumption of carbon based fossil fuels and nuclear
fission by-products plus diminishing economically
recoverable deposits of the fuels has stimulated
investigationof severalspace based energy sources.
Copyright 0 1992 by the American Institute of Aeronautics and Astronautics,Inc. All Rights Reserved.
*This paper is written in a personal capacity.
W
1
The physics of Helium 3 fusion are more difficult but the
industrial engineeringis more easy. The fusion research
community is in debate over its future direction? Figure
1 shows the program advocated by the Helium 3 workers
together with compatible space transportation
development milestones. Enough 3He is available on
Earth for the proposed research program spanning the
next 20years. The Moon isthe nearest repository of %e.
Billionsof yean of solarwind has deposited3He and other
volatile elements on the grains of the lunar regolith.
Moderate beating of the excavated fust 3 metres of

CIT Add pwer modules
czzzErI--
D+ He3 Breakeven 8 lgnibon
Fusion Power Commeraaltzaton
92 93 94 95 98 97 98 93 00 01 02 03 04 05 08 07 08 09 10 11 12 13 14 15
W Coherent infrastuetureplan based M IOW ops cost high availability, high capacity transporationoperations
etTechnokgyTestf l i h t s i n USA
Isuborbital and pmto orbitalvehicle
VTOLSingleStage aslunat transportdevel.
transpartsuch as HTOL or VTHL developed
Opera!hnal prototype developed
J'
1
rELVs used by spamagenciesfor lunar survey
n
I '
I DelivaHs3
Lunar operationsfor INTERLUNE
figure 1. Coherent development schedules
regolith to about 700' cwillrelease the gas for subsequent
processing to separate Helium, Hydrogen and other
usefulgases. The Heliummaybe exported to Earth asthe
primary revenue earning product of lunar industry.
Technologies from mining and civil engineering must be
combined into new lunar mining systems and
infiastrncture. Another source of %e is the atmosphere
of the outer planets but the space tmmpors common
technologies and cis-lunar infrastruchue are still required
for interplanetary operations.
There isa similartechnicalhurdle for SPSproponents. A
free electron laser transmission system, if perfected,
would enhance the system economics of in-space solar
radiation conversion concepts and radically reduce the
size of the energy beams aimed at the F.arth.4 Microwave
transmission requires multi-kilometer sized rectenna
arrays and tern of kilometer sized solar radiation collector
struetures in space. The economic life of the solar flux
collectors is determined by photovoltaic cell endnrance or
maintenance reqnirements of thermodynamic machinery.
A key factor in costing all of these large, by current space
engineering standards, projects is transportation. In all
W
cases the scenarios envisage the installation of thousands
of tons of facilityfabricated on Earth. Mature build-up
operations increase the annual transpon tonnage to tens
of thousands. Figure 2illustratesa transport requirement
scenario for h e consistent with the demand and
transportavailability xenario of figure 1.
The volume of Earth to Orbit traffic may be mitigated by
in sitn lunar resource utilization which wnsistently cuts
the total traffic. However the initial commercial
feasibility of these projects is dependent on space
transport based on Earth and a short period from
fmancial wmmitment to return on investment revenue
earnings. The pace of industrialbuild-up isalsogoverned
by the cislunar transpoa traffic capacity.
A true transpOaation system may be characterised as one
that is used by a commercial operator. It is cost effective
enough to permit competitive pricing. "be transport
operator contracts to load, deliver and unload cargo at the
end destination. A transport system that require._/
2

Bm.0
BM.0
7M.O
BM.0
BM.0
4M.O
3M.O
2 M . O
1m.o
0.0
2ooo 2M6 2010 2016 m 1(125 2Mo 2m6 avo 10(5 2050
1
Figure 2. Helium 3 scenario cislunar haffic demand.
intermediate unloading and reloading of thc cargo when
not strictly necwary is likely to incur unwanted direct
operating costs.
The transport vehicle may he endurance limited by fuel
Y capacity. Refuelling facilities are usually installed along
the route as part of the rran~portinhstruchue.
In the case of cis-lunar space bl.aosportation, the end
destination within cis-lunar space may he a Low Earth
Orbit of o p t i d inclination and altitude, a transfer orbit
providing access to the Clarke Orbit, the geosynchronous
Clarke orbit, a low orbit about the Moon or a landing site
on the Moon.
If the transport infrastructure is intended to only provide
terminal access to LEO, the cargo delivery or return
mission is quite simple to envisage. Regular and routine
support of orbital laboratory or production facilities plus
Figure 3. A typical multi-stage cis-lunar infrastructure
servicing or exchange of LEO spacecraft only requiresthe
reusable ET0 transport vehicle.
On the other hand, higher terminaldestinations may draw
quite complex itlfrastrucbxearchitecblres when the initial
Earth to Orbit and return vehicle is forbidden to venture
further out. Figure 3 illustrates a typical multi-stage
cislunar transpoa illfrastructuK.5
The standard conceptual solution is to provide upper
stage vehicles. Expendable or reusable concepts have
often been traded. A rewahle Orbit Transfer Vehicle has
the advantage when there is a reusable ET0 vehicle for
its support and the traflic rate works the transport system
to itscapacitylimits. Thesizeoftypicalpayloadsislimited
by the reusable E T 0 vehicle. Commercial
communications satellites are often used as payload
models. The consequentialarchitecture iterationprocess
attempts to select a single reusable O W or a two stage
3

solution that is able to he transported within the reusable
ET0 vehicle in modular pieces. This applies to the
vehicle and its loaded propellant tanks.
Module Kceipt from an ET0 transport, on-orbit storage
and subsequent assembly, checkout, payload integration
to the OTV, despatch flightoperationsand recovery of the
OTV stages are the inevitable in-orbit operationsthat will
recur with each multi-stage or multi-element mission.
This scenario applies to delivery of large modules to a
LEO Space Station, deliveryof a geosynchnous satellite
or SPSpieces, servicingGEO satellitesor missions to Low
Lunar Orbit or Lunar Surface Sites.
A LEO based OTV will require refuelling operations in
orbit or periodic swapping with a fresh Earth based OTV.
In either case there are a number of ET0 flightsdedicated
just to support theOTV's direct operations. SeveralET0
launches are required for each GEO or Lunar mission.
Many studies simply discard an OTV at the end of its
operational life of perhaps 20missions.
Very often a Space Station or single function Spaceport in
LEO is identitied within an infrastructure. It may be
debated that a Spaceport is inevitable, as illustrated by the
proposed SEI Saturn 6 new Apollo infrastructure. A
reusable cis-lunar transport infrastructure at least
requires a refuelling function after achieving LEO from
the Earth surface. Traffic rates of more than ten lunar
landings per year will require a very complex and
expensive organization of supporting O W flights, ET0
deliveries, space traipfic control and logistics?
If a rocket propelled SSTO vehicle could be refuelled
after achieving EO,it would have approximately the
correct delta V capability to perform a lunar landing and
return to Earth via an aerobrake manoeuvre. A
comparison of lunar mission velocity estimates is given in
Table 1. The mriations can be attributed to assumptions
about the initial and return parking orbirs about the Earth
Figure 4. Single Stage cis-lunar transport infrastructure
1900
- 2900
Snrfaceto'Rans 2510 2550 2800 + loo0
Earth Coast
i
and about the Moon. The number of rendezvous and
dockings with parked stages may also inflate the
estimates.6,7,8*9 The delta V performance required of a 4
VTOL SSTO vehicle is about 8755 Ws.6
Aerobrake to
eliptical LEO
CircularizeLEO 310 600 200 200
.LEO to Landing 1450
TOTAL 8530 8755 9100 9350
BETA ""1,- BAe
LunarMission IAF 7
Phase ,-90"06!?&elle)!1985cock IL T A ~
Earth To Orbit
LLO Insertion
Table 1. Delta V (m/s)budgets comparison
An obvious problem for a winged Horizontal Landing
SSTO is the lunar landing which requires a Vertical Takev
Offor Lauding (VTOL) mode of o eration. Tangential
lunar landers have been proped' but have not been
considered as a functional capability of a conventional
Earth based Horizontal Landing SSTO concept.
L u u F e e ~ w m i ~
Assuming that a VTOL SSTO vehicle has k e n designed
with transport aircraft-like safety and engine-out
capability", there is no compelling reason to take a
trajectorythat includesa parkingorbit about the moon. A
direct trajectory of a fully fuelled Lunar Ferry in LEO to
the lunar surface Spaceport is feasible. Indeed such a
4

trajectory is much less sensitive to orbital plane
alignments and associated LEO departure and return
Qonstraints. Figure 4 illustrates the principal
characteristics of Single Stage cis-lunar or "Lunar Ferry"
tramport infrastructure.
In an initial operations mode there would be an absence
of any lunar surfaceindustrialproduction of liquid oxygen
(LOX) and the high value Helium; and only a minimal
Lunar Base. The Lunar Ferry would have its pallet
mounted cargo, that WBS loaded at the Earth surface
Spaceport, unloaded by automated and tele-operated
material handling equipment that is similar in function to
the Eanh spaceport fork lift pallet moving equipment
(delivered on the fmt landing mission).
The SSTO "Lunar Ferry" vehicle may launch into a direct
trajectory aiming for an aembrake encounter with the
Earth's atmosphere. The velocity change for the
aerobrake will decelerate the Lunar Ferry by sane 3000
m/s. Thisismuch lessthan a fullre-entry so there maybe
no special uprating requirements for the rexntry Thermal
Protection System.
After entering an elliptical LEO, the Lunar Ferry
performs some parking orbit operations before an optimal
trajectory for reentry and cross range hypersonic flight to
the home Earth base can be initiated. A standard vertical
"landing is performed and the turn-around operations
commence again for the next Lunar Ferry mission.
Refuelline
The obvious problem of refuelling the SSTO Lunar Ferry
in LEO is solvable by launching the 550 metric ton of
cryogenic propellants needed by a Delta Clipper DC-Y
sized SSTO" (10 metric ton of cargo to LEO) on a series
of expendable Heavy Lift launchers. Thiswould require
a very tightly scheduled operation to avoid excessive
boil-off losses. Many rendezvous, docking and fuel
transfer operations would be performed in preparation
for each lunar mission. Alternativelyone or more orbital
tank farms could be constructed to store and maintain
thousands of tons of cryogenics to support a modest initial
Moon base build-up. The recurring ET0 tanker launches
in support of each lunar mission remains unattractive,
however.
Another SSTO Lunar Ferry architecture depends on a
system fmt analysed in the late fifties, again in the sixties
and revisited in the late se~enties.'~.'~A facilitycalledthe
Propulsive Fluid Accumulator (PROFAC) by its creatorW
can scoop air at an orbital altitude of 120 km. The air
density is sufficient to assure a reasonable accumulation
rate without demanding an infeasible level of continuous
drag compensatingthrust.
Prupulsion for PROFAC would be an electric arc jet
rocket that uses the accumulated liquid nitrogen as
propellant. The LOX is stored for eventual transfer to a
Lunar Ferry orother customer. The early design analysis
indicated that a PROFAC would require a 6 MWe power
source such as a nuclear h i o n reactor. This size of
power plant also appeam to be appropriate. for many
Lunar Base and mining-refining proposals.
The initial reaction to the above idea stirs concerns abut
a nuclear reactor orbiting at such a low altitude. The
safeguardsdesigned into SP-lo0 or TOPAZ =actors plus
additional safety features that become apparent with
some speculation can be considered affordable. The
delivery system for PROFAC units would be a 10 metric
ton to LEO SSTO vehicle. Automated assembly of a
PROFAC that may have a totaldry mass of 180metric ton
can be envisaged as similar to modular Space Station
construction. A fleet of several PROFAC's would be
needed for several years until lunar oxygen production
was adequate for the Lunar Ferry Wit.
If the 'Mat-if-everything-failed" scenario was ever to
eventuate, there. would not be a repeat of the COSMOS
954 incidentof 1978. The launch on demand capabilityof
the SSTO fleet would ensure that a rescue booster tug unit
could be rapidly delivered to a disabled PROFAC.
Initial calculationsof a VTOL SSTO Lunar Ferry mission
scenario indicate the following characteristics.
A Lunar Ferry GLOW will be some three times as massive
as the reference 600 ton Delta Clipper. A modest
increase of engine performance (Isp of 445 sec), while
retaining aircraft engine-like maintenance is assumed.
The cargo bay payload would be 9 metric ton for a lunar
return trip in the case of a crewmodule. Some 11.5 ton of
cargo could be delivered to the lunar surface. The Lunar
Ferry is sized to carry propellant sufficient to leave 136.5
ton of liquid hydrogen (LH2) in the tank plus enough
LOX to permit a return to Earth Base from LEO. The
Lunar Ferry which now bas a mass of 258 ton (80 dry mass
+ 136.5 H2 propellant cargo + 9 'crew cabin + 32.6
contingency re-entry and landing propellant) performs a
5

rendezvous with one of 8 PROFAG that Serve a 10 lunar
mission per year M i c flow.
The standarddocking operationis similarto the proximity
operations of other Lunar Transport System concepts that
are assembled in LEO. Some 714 tan of LOX is
transferred to the Lunar Ferry. After separatingfrom the
PROFAC, the Lunar Ferry performs operations for Trans
Lamar Injection.
Navigation to a lunar landing site equipped with beacons
ensures precise direct descent landing at a lunar
spaceport. Early Lunar Ferry operations will require the
above mentioned propellant loading in LEO. As the
minmg and magma electrolysis processingls of lunar
regolith becomes operational,Lnnar Ferry LOX demand
Moon ofsome2500ton offacility. The searchfor a LLOX
production process with optimal specific delivery and
logistics support mass to LLOX output is therefore to beu.
encouraged. In the same time frame %e mining
equipmentwould also be. delivered to establiish revenue by
export o€thefust 100Kg after one year of operation. This
would yield up to 600 ton of liquid hydrogen without
considerationof losses. The completerangeof synergistic
pibilities has not yet been examined." One data point
example is described below.
As the LLOX production rate is increased through the
delivery of more mining and refining equipment,exportof
LLOX to LEO becomesfeasible. Tbiimode -3-permits
fnrther traffic rate increases to 36 deliveries per year,
liited by the PROFAC LOX production rate, and would
Slngle Stage Lunar Ferry propellantrequiramentaand export capability
Mstrk
TOW
C I R a1 Lunar Fery Unkuprltyllmltsd lord.
1200 M n D
1000
8w
MI0
400
aMI
0
LOXCargoEarthto LEO
LH2 Cargo Earthto LEO
PROFAC LOX produdlon por
lunar tory mlsdon
LEOoffload LOX(lunar export
for nertmlulon)
Q LEOoffload LH2(Lvnuexport
for next LunarFery mlsslon)
I& LUNOXtotal lunaroxygen
prodwtlon p r Lumr Ferry
mlWon
L U M ~HyOrogenprcdudlon for
Lunar Fory mlselon
v N O d d B 3 : g b
%! 2 g ForLEOloMOONtheLOXroqulred
w
s = = a ! I I Or Or Or Or - L O X C ~ ~ ~ ~ + P R O F A C L O X +
w % ! w8 0 8 # ; 8
Lunar Export LOX
Figure 5. "Lunar Ferry" propellant tanker possibilities
in LEO reduces to about 300tons. The return to Earth
LOX propellant load of some 214 ton is supplied by
LLOX. Therate oflunar ferrymisiansmaybemore than
doubled in this operational mode - 2 - as soon as LLOX
production rates are appropriate.
The tonnage of LLOX production facility is a matter of
estimation from various recent studies.I6 A nuclear
powered continuous mining and processing facility
supplyingsome 5000 ton of LLOX per year for 25 Lunar
Feny flights per year may require the delivery to the
.J
most likely require a fleet of two active Lunar Ferries.
The establishment of the fust Helium 3 mining operation
provides large amounts of liquid Hydrogen as a
by-product.2.3 Another Lunar Ferry mission mode - 4 -is
enabled and the need for PROFAC LOX production is
eliminated. The PROFAC units may be retired or
converted to non-nuclear powered tank farms in a higher
lowdrag orbit. Export of LH2 to LEO permits dry cargo
delivery to the Mow to be increased to 136 ton with a
suitablevariant of the Lunar Ferry in mode 5.
i
6

As the Lunar industrial infrastrucmre grows, a point will
be reached where Moon Based Lunar Ferry operations
-.-,baybecome competitivewith Ear+ based operations. In
this mode - 6 - propellant exports to LEO can be
maldmid or cargo tonnages increawd. A mixof various
Earth based SSTO vehicles with unproved operations
economies may emerge. A Moon based Lunar Ferry
could collectup to 150 ton of cargo fmn a LEO spaceport
and transport it to the Moon without any propellant
export in mode 7.
Figure 5 indicates the propellant consumption and export
potential of the SSTO Lunar Ferry operation modes
described above.
These major Lunar Ferry modes illushate the inherent
flexibility of a Single Stage Rocket cis-lunar transport
architecture. There will be other missions within the
Earth-Moon system to further expand the market. The
resiliency of this architecturecan cope with a slow WIG
build-up or a very rapid growth rate. The supply and
demand for Helium 3 has been plotted for a scenario
where 25 % of world electricity generation is provided by
D+ %e fusionreactors in 2050. Thisisa medium growth
rate scenario when com ared to the growth of fBsion
power in some The Lunar Ferry trafficbased
on 10 ton cargo deliveries grows to 600per year by 2050
Figure 6. Cislunar transport architecture comparison.
Cis-lunar Transport Archltectum Comparison
where halfof the landingsdeliver %e mining equipment.
This rate may not be necessary because larger cargo
capacity Lunar Ferry derivatives will emerge as the lunar
industrial infrastructure grows.
The initial Lunar Ferry mission direct operations cost has
been estimated at$150million assnminga $10 millionper
fight SSTO ET0 cost and return on investment for the
PROFACs within five years. DDT&E investment
amortization for the Lunar ferry SSTO variant and
PROFAC is implied by generous operating profit margin.
Amortization of a relatively low infrastructure
development cost is assured by the large number of
frequent missions. The transport infrastructure recurring
costs are the lowest achievable because the single stage
architecture of the infrashlctnre avoids multiple ET0
deliveries to a LEO Spaceport for re-assembly of h a r
Transport Systems for each and every mission. Figure 6
summarizes a survey of operations characteristics of
cis-luoar traosport architectures.
If the PROFAC concept is not implemented, it is also
feasible to adopt a variant of the Lunar Ferry SSTO to
carry some 150 ton of ppellant to a LEO cryogenic
propellant storage facility. The Lunar Ferry fleet size
would increase but this may be considered as extra
resiliency of the transport infrastructure. The assumed
-10.0 40.0 0.0 10.0 20.0 50.0 40.0
*/
7

cnst for ET0missions can also he expected to reduce with
operational experience to perhaps $1 million per
flighL'9JO
Ground operations include the post fight inspection and
routine maintenance of the Lunar Ferry. This direct
operating cost is certainly far less than for a LEO
spaceport function that would pass on the cost of
operation of a very large manned orbital facility or set of
space station facilities. The experience gained from the
Eaah Spaceport can he applied to a highly automated
Lunar Spaceport that provides a materials handling
facilityfor the offloading of cargo pallets. They must be
transported by road to shelters constructed to provide
shielding and thermal stability on the lunar surface.
Refuelling services will be established so that the
propellants can he efficiently transferred from protected
holding rank farms.
An unmanned scenario can be envisaged where
tele-operation of lunar robots is sufficient to implement
construction of the spaceport and cargo handling
facilities. After the initial base has been delivered and
partially deployed, a construction crew can be landed.
Commissioning of the fnst regolith covered habitat
facilities would be performed as well as numerous other
tasks deemed too complex for tele-operated robots.
The planning of a lunar surface infrashlcture is beyond
the scope of this paper but a few comments about the
Figure 7. V M L SSTO and Lunar Ferry evolution
cargo tonnage and infrastructure architecture are
n v .
The character of lunar surface equipment and facilities
will not he driven by aerospace design criteria. The
specific ooSt per Kg will need to be more. comparable to
terrestrial offshore facilities costs. Therefore the
tonnages will he higher than many Lunar Base studies
have assumed.
The justifidon for LEO Space Stations as technology
demonstrators for future applications is weakened since
facilities for lunar surface operations can he developed
and tested on Eanh and then directly delivered to the
destination in a rapid industrialization program.
The often impwed requirement that a LEO space station
such as Freedom, Mir 1 or a future -1s Mir 2 he
used as a transportation node is challenged by this single
stage transport architecture.
A fuel storage facility is mandatory in LEO but its size,
mass and traffic characteristics are grounds for separating
a manned orbital research facility. Indeed the desired
orbits are likely to be incompatible. The cis-lunar
refuelling stations are best located in low inclination to
maximize lunar mission launch and return windows.
The Lunar Ferry is not the only mission well supported by
the aboveconcept. The HeavyLift SSTOLunar Ferrycan
v
t/
Sub-orbital SSTO Mkl
Reusable o Development
o Development o Sortie business
o LowOperations o Sub-orbital Transport
Cost Demonstrator o SSTO with small payload
o Catalyst for commercial
Space Industry
SSTO MIO
o Operational
o 10Ton
o Qx4.5x4.5m
o Operatedby
Commercial
Companies
Lunar Ferry
o SSTO
Variant
with extra
LH2 capacity
8

also perform missions to Clarke orbit. The propellant
supply from the Moon stored conveniently in LEO opens
vnany true space tmqortation possibilities.
The build-up of this infrastructurewill quire funding in
the region of billions of dollars as do all new space
transport concepts. The amounts of finance are
comparitively modest when measured against large civil
engineering projects. The space community has been
unable to sustaingovernment funding at optimal levels for
the major infrastructure projects that have characteristic
times of a decade or two. Thii is due to a degree of
incoherence of the built (and sometimes abandoned), to
be built and proposed infrastructure elements. The goal
of a space infrasmucture has not been clearly stated by
the space communityagencyand industryleaders. Critics
who are content with old ordinance derived space
transport are able to exert influence and often stall
initiatives for more effective space transportation. Rival
visions of space transport infrastructures or, more bluntly,
market opportunities also fail to present a clear, credible
beneficial goal that provides a re.mon investment.
This paper has described a scenario of industrializationof
the Moon as a forseeable goal necessary for any space
gerived energy project for the existing market on Earth.
'-The total system a t includes the recumng operations
cost as well as the initial hurdle of design and
developement costs. Short term budget limits
accommodated by reducing the operational efficiency of
the transport system are well known in the space
community. This phenomenon can be expected again.
A strategy for a step wise development and introduction
of operational capability and revenue generation is
mandatory. A VTOL spaceplane can evolve as an
operability demonstrator, sub-orbital carrier, modest
Earth to Orbit and then grow the basic configuration to
heavylift capabilityasshownin figure 7. The growthpath
builds directly on acquired operational experience and
lessons. With each new VTOL SSTO derivative the
credibility and abilityof the developers to gainf m c e will
become more like conventionalterrestrial industry.
A slow space market growth scenario can be
accommodated. Sub-orbital operations can slowly
cultivate a market for orbital delivery and retrieval
transport service. The expected "break-throughs"in the
space power domain will occur, despite ever present
sceptics. An order of magnitude, or even two, reduction
of a t for effective space transportwill be demanded.by
be market. As explained here, the requested journeywill
v
be to reach the Moon on a routine and frequat basis for
illdustxial operations.
Aeropace industry svategists can today assess the market
potential of the various aemspace plane coniignmtions
advocated by technologists. Business success relies on
correctly identifying new markets.
Aclolowlednement
The investigation of a single stage aansport architecture
was stimulated by an ongoing ESA funded study
(SYSTEMS4 led by ERN0 Raumfabrttechnik GmbH)
that set the Helium 3 scenario described here. as a goal in
a European Manned Space Infrastructure beginning with
the now indefinitely suspended Ariane 5 launched
Hemes space lane and Columbus Man Tended Free
Flier projects.
The author wishes to thank Russell Hannigan of ESYS for
providing the timely opportunity to write this paper.
8
1.
2.
3.
4.
5.
Proceedings of the Second International Symposium
SPS 91 - Power From Space, 27-30 August 1991,
Paris,Societe des Ingenieurs et Scientifiquesde
France OSF)
Fusion Power from Lunar Resources,G. L.Kulcinski
and H.H. Schmitf, presented at 41st Congress of the
International Astnmautical Federation, Dreden,
Germany Oct. 1990.
Report of NASA Lunar Energy Enterprise case Study
Task Force, NASA-TM-101652, July 1989.
Power Satellite Study for EUROSPACE by R. J.
Hannigan, f& presentation ESA Paris, March 11,
1992.
Built-in Simulator and Intelligent Manager
Architecture for Autonomous Scheduling of OTV
Network Operations, Shinichi Nakasuka and TON
Tanabe, WAC Workshop on Spacecraft Automation
and On-board Autonomous Mission Control,
Darmstadt,Germany Sept., 1992.
9

6. Designing the Space Transfer Vehicle: The Piloted
Lunar mission, G.Austin and T. Vi@,
~ - 9 a i 7 0
7. Orbital Transfer Systems for Lunar Missions, D. E.
Koelle and M. Obersteiner, IAF-91-181
8. British Aerospace Long Term Architecture Study
papers, Hempsell, F’arkinson, Salt et al
9. Mission and Operations Modes for Lunar Basiig, G.
L,Woodcock, Lunar hses and Space Activities of
the21st Century, W.W. Mendell, Ed. 1985
10.Lunar Industrialization and Settlement - Biah of
Polyglobal Civilization, K. A. Ebricke, Lunar bases
and Space Activities of the 21st Century, W.W.
Mendell, Ed. 1985
11.Single Stage Rocket Technology, W. A. Gaubatz, P.
L,Klevatt and J. A. Cooper, IAF-92-0854
12.SSRT Brochure on Delta Clipper, March 1992
13.Ihe Air-scooping Nuclear-Electric Propulsion
Concept for Advanced Orbital Transportation
Missions, R.H.Reiche1, J.Brit.Interp1anetary Soc.
Vol31 pp62-88,1978
14.Earth-Moon Transportation Options in the Shuttle
and Advan4 Shuttle Era,R. C. Parkhon, IBIS
Vol34,pp51-57,1981
15.Lunar Liquid Oxygen hoduction Facilities, J. Pulley,
C. Goodmanand Al Tanner, Proceedings of
Engineering, Coastruction and Operations in Space
III,ASCE, Denver, Junc 1992
16.Ptoceediigs of Engineering, Construction and
Operations in Space III, ASCE, Denver, Junc 1992
17.Synergism of He-3 AcquisitionWith Lunar Base
Evolution, T.M.Crabb and M.K.Jacobs, pnxented at
Lunar bases and Space Activities of the 21st
Cenhuy, Houston, 1988
18. Environmental Aspects of Lunar Helium-3 Mining,
G. L. Kulcinsld, E. N. Cameron, W. D. Carrier III,
H.H. (Jack)Schmitt, p606, Proceedings of
Engineehg, Coastruction and Operations in Space
I Q ASCE, Denver, June 1992
19.Sigle Stage To Orbit, the Rapid Tunmound
Launch Vehicle, R.S.Spain, R.A.Hiclaaaa,
IAF-924883 v
2O.Logistics Snppla of Lunar Bases,G.R. Woodoock,
1988
21.Missicm to SAVE Planet Eaah, J.Sved and
P.W.Sharp, proceedmgs of SPS 91 - Power From
Space,27-30 August 1991,Paris.
10

6%2E1992-5082

Recommended

Recommended

More Related Content

Viewers also liked

Viewers also liked (17)

Similar to 6%2E1992-5082

Similar to 6%2E1992-5082 (20)

6%2E1992-5082