Adrian Nixon and Rob Whieldon are some of Britain’s leading experts on Graphene – its chemistry, manufacture and uses. In this presentation they will lead us through the journey of graphene from its origins in playing with pencil and scotch tape to its future its uses - from transparent toasters to the Space Elevator.

1. RGU – PMI UK North
Scotland Region
How pencils and scotch tape led to
the Space Elevator

2. PMI Aberdeen
5th December 2023
How Pencils and Scotch tape
led to the Space Elevator

3. What we will talk about…
• Who we are
• Graphene the origin story: Impossible to Industrial
• How rockets work and their limitations
• What is a space elevator and how it overcomes these limitations
• The state of the art in tethered lift manufacturing
• Could a space elevator really be built?

4. Who we are

5. Rob Whieldon
Director of the Nixene
Journal focused on graphene
and 2D
Award winning business
coach, over 20 years'
experience supporting
businesses
Introduced Goldman Sachs
10,000 Small Business
programme to the UK
Small Business Charter Gold
Award

6. Adrian Nixon
Editor
of the Nixene Journal
Member of the Royal
Society of Chemistry and
Chartered Chemist
Over 30 years’ experience
in industry Technical
Service, Industrial R&D,
strategic level consulting
Member of the board of
directors of the
International Space
Elevator Consortium (ISEC)
International Space Elevator Consortium

7. International Space Elevator Consortium
An international
not-for-profit
organisation based in
California, USA
members worldwide
www.isec.org

8. Nixene Publishing is based at the
Graphene Engineering Innovation Centre (GEIC), Manchester
A world-class, multi-million-pound
centre for industry-led development in
graphene applications in partnership
with academics.
The GEIC specialises in the rapid
development and scale up of
graphene and other 2D materials
applications
The GEIC Masdar building. Image credit: Adrian Nixon

9. Graphene. The origin story
Impossible to Industrial

10. Pencils
The part of a pencil that draws the line
is called lead
It is not lead (Pb)
It is graphite
Pencil line. Image credit: Adrian Nixon

11. Graphene: The origin story
Graphite and Graphene
Multilayer graphene exists in nature as graphite
The bulk material is made of jumbled stacks of nanoplates
Graphite
Multi-layered
graphene nanoplates
During the 20th century physicists
argued convincingly that materials
like graphene would be too
thermodynamically unstable to exist
Graphene
single atomic layer of carbon
Sources:
Sachdeva, G. (2011). Graphene: The coolest material that shouldn’t exist. Available at:
https://sitn.hms.harvard.edu/flash/2011/graphene-the-coolest-material-that-shouldnt-exist/ [Accessed 22 Nov. 2023].

12. Graphene: Sticky tape

13. Graphite to Graphene with sticky tape

14. Graphene: A two-dimensional (2D) form of carbon
This graphic is copyright free
Image credit: Adrian Nixon created using Samson-Core molecular modelling

15. Ten things to know about Graphene:
The new advanced material revolution
200 times
stronger than steel
World’s best
conductor of electricity
Flexible and
transparent
Highest melting point of any
material in a vacuum
100 times more
tear resistant than steel
One of the World’s best
conductors of heat (hBN)
World’s most
fatigue resistant material
Very stable material
Non-toxic 
World’s most
impermeable material
Source: https://www.nobelprize.org/uploads/2018/06/advanced-physicsprize2010.pdf
Scratch resistant
to diamond

16. Nobel Prize in Physics 2010: Graphene
Pencils and scotch tape
Graphite
2004 Graphene isolated
as world’s first 2D material
using sticky tape
2010
Andre Geim &
Konstantin Novoselov
Win Nobel Prize
For preparing and
characterising graphene

17. The impossible…
For years researchers have been using
sticky tape to prepare graphite samples
for electron microscopy work
Everyone accepted the view that graphene
was impossible to isolate from graphite
‘What those guys did not realise, was that
throwing away the Scotch tape they were
throwing away the Nobel Prize as well.’
Andre Geim
Highfield, R. (2015). Secret of Scientific Creativity revealed by Andre Geim. [online] Science Museum Blog. Available at:
https://blog.sciencemuseum.org.uk/secret-of-scientific-creativity-revealed-by-andre-geim-godfather-of-graphene/ [Accessed 28 Nov. 2023].
Scotch tape used for isolating graphene from graphite
Museum of Science and Industry at Manchester, UK
Image credit: Adrian Nixon

18. …To Industrial
Thousands of tonnes of graphene are made each year
The new Huawei Mate X3 folding smartphone has an improved graphene cooling system
The next Apple iPhone is said to have
graphene heat management

19. Sports bicycle tires enhanced with graphene
Source:
https://road.cc/content/tech-news/256990-vittoria-corsa-tyre-goes-tubeless-new-graphene-20-tread-compound
Mileage Speed Air
Retention
Grip Cut
Resistance
Without graphene
With graphene 1.0 compound
With graphene 2.0 compound
Vittoria have developed a functionalized graphene to
further improve the performance of sports road tires

20. …To Industrial
Graphene in more than 5 million Ford cars
Since 2019 all ford Mustang and
F-150 models contain graphene
enhanced components
-17%
20%
30%
-20%
-10%
0%
10%
20%
30%
40%
Noise
Reduction
Mechanical
properties
Heat
Endurance
Graphene Polymer Composites
Found that less than 0.5% addition of
graphene nanoplate to polyurethane foam
gave the optimum results
Source:
https://www.rubbernews.com/article/20190207/NEWS/190209966/fords-finds-graphene-helps-pu-rise-to-challenges

21. Source:
Anon, 2021. Secret sauce: how graphene lowers building costs and CO2. [online] Secret sauce: how graphene lowers building
costs and CO2. Available at: <https://www.manchester.ac.uk/discover/news/roller-disco-vs-climate-change--how-graphene-is-
…To Industrial
Concretene: Graphene enhanced concrete 30% stronger
Vol 6 iss 3
Image credit: Nationwide Engineering Group
The finishers could begin work while the pour
was still taking place at the far end
Normal concrete
takes 28 days to
achieve its strength
Graphene-enhanced
Concretene achieves
28-day strength in 24 hours
54 x14 metre mezzanine floor

22. How rockets work, and their limitations

25. The rocket equation
Where:
𝑣𝑒 = 𝐼sp g0 is the effective exhaust velocity
𝐼sp is the specific impulse in dimension of time
g0 is standard gravity
ln is the natural logarithm function
𝑚0 is the initial total mass, including propellant, a.k.a. wet mass
𝑚𝑓 is the final total mass without propellant, a.k.a. dry mass
𝚫𝑣 = 𝑣𝑒 ln
𝑚0
𝑚𝑓
= 𝐼sp g0 ln
𝑚0
𝑚𝑓

26. Another way of looking at the rocket equation.
The boat experiment
Imagine you are in a boat away from the shore without oars.
You want to reach this shore.
You notice that the boat is loaded with a certain quantity of stones…
Newton’s Third Law of Motion
states that for every action,
there is an equal and opposite
reaction.
Source:
Konstantin Tsiolkovsky. 1903. The rocket equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
3 Laws

27. • 4% of launch pad mass gets to Low Earth Orbit (LEO)
• 2% of launch pad mass gets to Geostationary orbit (GEO)
• 0.5% of launch pad mass gets to the Moon and Mars
• Only 20,000 tonnes have been delivered to LEO: 1957 to 2020
• 1/2 m tonnes required for moon base
• 1m tonnes required for Mars
Rockets have limitations
Sustainability
In 2021 rockets put one million kg of black
carbon pollution directly into the stratosphere
Rockets are good for lifting people
But: Rockets have limited capacity
Sources:
[1] Swan, P., Swan, C., Phister, P., Dotson, D., Bernard-Cooper, J. and Molloy, B., 2022. The Green Road to Space. ISEC Position Paper # 2021-1. [online] Santa Ana: International Space Elevator Consortium.
[2] Maloney, C., Portmann, R., Ross, M. and Rosenlof, K., 2022. The Climate and Ozone Impacts of Black Carbon Emissions From Global Rocket Launches. Journal of Geophysical Research: Atmospheres, 127(12).
https://doi.org/10.1029/2021JD036373

28. Elon Musk and Mars
Musk estimated in 2019 that it would
take around one million tonnes of cargo
to build a self-sustaining city on Mars.
Designs for microwave transmitting satellites are
massive, with solar reflectors spanning up to 3 km and
weighing over 80,000 metric tonnes. They would be
capable of generating multiple gigawatts of power,
enough to power a major U.S. city..
Plans for space:
Space based solar power
1. https://www.inverse.com/innovation/spacex-mars-city-codex
2. https://en.wikipedia.org/wiki/Space-based_solar_power
Image credit: NASA

29. In the history of rockets
from 1957 to 2020
only 20,000 tonnes of mass
has been lifted into space
Lifting large amounts of mass to
space
1. https://www.linkedin.com/pulse/space-elevators-overview-part-3-international-space-elevator-conso/
Rockets cannot deliver the mass
needed for future planning
A space elevator can lift
more mass than rockets
Image credit: SpaceX

30. What is a space elevator
and how it overcomes the limitations of rockets

31. Konstantin Tsiolkovsky 1857 - 1935
Konstantin Tsiolkovsky saw the Eiffel
Tower and thought of keeping going...
He proposed a tower reaching
geosynchronous orbit first published in 1895
As well as defining the rocket
equation, Tsiolkovsky was the
first to think about alternative
ways of accessing space

32. 32
Space Elevator Inventor [1]
Yuri Artsutanov (1929-2019)
born in Leningrad : a graduate of Leningrad Technological Institute
"в космос на электровозе"
Komsomolskaya Pravda, 31 July 1960
(English translation “Into the cosmos by electric
train” by Vladimir Lvov in Science, Vol 158, Issue
3803, pp 946-947, 1967)
Described the basic concept
of the Earth Space Elevator

33. 33
Space Elevator Inventor [2]
Jerome Pearson (1938-2021)
“The Orbital Tower: A Spacecraft Launcher Using
the Earth's Rotational Energy”,
Acta Astronautica Vol. 2, pp. 785–799, Sep/Oct 1975
Presented at the 27th IAC
in Anaheim, California (10-16 October 1976)
Detailed mathematical analysis

34. What is a space elevator?
• A space elevator is conceived as a cable fixed to the equator and reaching
into space.
• A counterweight at the upper end keeps the center of mass well above
geostationary orbit level.
• This produces enough upward centrifugal force from Earth's rotation to fully
counter the downward gravity, keeping the cable upright and taut.
• Climbers carry cargo up and down the cable.

35. The Space Elevator components (not to scale)
Earth Port
Climber
Tether
Geostationary Node
Apex Anchor
Tether length
100,000 km
Diameter of earth
12,742 km
South pole

36. Space Elevators in Science Fiction
Arthur C. Clarke
Other writers

37. The Space Elevator idea spans 3 centuries
The 19th Century
• Konstantin Tsiolkovski: a tower reaching geosynchronous
orbit first published in 1895
The 20th Century
• Artsutanov, Yuri. 1960. V Kosmos na Elektrovoze,
Komsomolskaya Pravda, contents described in Lvov 1967
Science 158:946 “to the cosmos by electric train”
• Jerome Pearson 1975. “The Orbital Tower: A Spacecraft
Launcher Using the Earth’s Rotational Energy” Acta
Astronautica. Vol. 2. pp. 785-799. Pergamon Press 1975
• Clarke, A.C. 1979. The Space Elevator: ‘Thought
Experiment’, or Key to the Universe. Adv. Earth Oriented
Appl. Science Techn. 1:39
The 21st Century
• 2011 ISEC “Appears Technically Feasible”
• 2023 Current status “Ready to start development

38. Space Elevator Science Fact: NASA / ISEC
2003 Study by Bradley
Edwards funded by NASA
Institute for Advanced Concepts
2013 IAA
Publication
2019 IAA
Publication

39. • A space elevator is conceived as a cable
fixed to the equator and reaching into space.
• A counterweight at the upper end keeps the
center of mass well above geostationary orbit
level.
• This produces enough upward centrifugal
force from Earth's rotation to fully counter the
downward gravity, keeping the cable upright
and taut.
• Climbers carry cargo up and down the cable.
What is a space
elevator?
Source:
https://en.wikipedia.org/wiki/Space_elevator

40. Why Does the Tether Stay Up?
Because the force of gravity at the
bottom and the upward/outward
centrifugal force at the top
compete keeping the rope taut
For this reason, locate at the
equator.
But where on the equator?

41. Where to locate the Earth port?
On the sea, at the equator, but where?
What problems might we have to think about?

42. Recorded tracks of tropical storms
1856 - 2006
https://earthobservatory.nasa.gov/images/7079/historic-tropical-cyclone-tracks

43. Commercial Airline Traffic
https://en.wikipedia.org/wiki/Commercial_aviation

44. Lightning rate: <10 km-2 year-1
Ecuador
Proposed Anchor
zone
Pacific Ocean
1000 km
10/15/2015
Lightning flashes recorded by NASA Satellites

45. Marine Node – Today’s technology
Earth port is a marine
node
A mobile, ocean-going platform
identical to ones used in oil drilling
Anchor is located in eastern
equatorial pacific, weather and
mobility are primary factors

46. Climber – Today’s technology
Climbers built with current satellite
technology
Drive system built with DC electric motors
Photovoltaic array (GaAs or Si) receives
power from Earth
7-ton climbers carry 13-ton payloads
Climbers ascend at 200 km/hr
8 day trip from Earth to geosynchronous
altitude

47. Climber:
Is the tether
climbable?
Wright, D.H., Bartoszek, L., Burke, A.J., Dotson, D.L., Hassan El
Chab, Knapman, J., Lades, M., Nixon, A., Phister, P.W. and
Robinson, P. (2023). Conditions at the interface between the
space elevator tether and its climber. Acta Astronautica,
211(October 2023), pp.631–649.
doi: https://doi.org/10.1016/j.actaastro.2023.06.047 .
Yes

48. Geo Node and Apex Anchor
Today’s technology
We’ve already
built the International
Space Station ISS
419,725 kg
https://simple.wikipedia.org/wiki/International_Space_Station
Building the geo node and apex
anchor in space is feasible

49. The Space Elevator components:
Our checklist
Earth Port
Climber
Tether
Geostationary Node
Apex Anchor
Tether length
100,000 km
Diameter of earth
12,742 km
South pole
✅
✅
✅
✅

50. Is the space elevator feasible?
In 2000 NASA’s Institute for Advanced Concepts NIAC
Commissioned Dr. Bradley C Edwards to examine the reality
of the space elevator
He reported phase 1 in Oct 2000
Phase 2 in March 2003
Asked is this do-able with today’s technology?
Answer, Yes – Apart from one thing…
https://en.wikipedia.org/wiki/Bradley_C._Edwards
In 2013 The IAA
Looked at technical and commercial issues
Asked is this feasible to build, and how might we actually do
this?
Answer, This can be done – Apart from one thing…
https://www.amazon.co.uk/Space-Elevators-Assessment-Technological-
Feasibility/dp/2917761318

51. The space elevator tether…
NASA and the IAC agree
A tether material needs to be incredibly strong and light

52. Illustrating the tether material
problem
Imagine you are
standing at the edge of
an infinitely high cliff
You lower a super strong
cable over the edge
The cable eventually breaks
under its own weight
Image credit: D. Valdermaras, Unsplash

53. Tether material needs
The tether material needs to be both lightweight
and super strong
Strength is measured in Pascals (Pa)
Today’s super strong materials such as Kevlar
have strengths around 3.7 GPa
The space elevator tether requires material with
a strength of over 60 GPa, preferably 100 GPa
Edwards. B, (2003) The Space Elevator NASA Institute for Advanced Concepts (NIAC) Phase II Final Report
http://images.spaceref.com/docs/spaceelevator/521Edwards.pdf

54. The space elevator can be made with
today’s technology, can the tether?
• The tether is a continuous piece of material
• One Hundred Thousand Kilometres long
• Stretching from the surface of the earth into space
• It must support the mass of Climber and payload
• It also must be strong enough to support itself

55. Space elevator tether materials
0.1
0.1
1.0
10
100
1.0 10
1000
Wood and wood
products
Polymers
Rubbers
Porous
Ceramics
Composites
Metals
Tensile
Strength
(GPa)
Density (g/cm3) With thanks to Mark R. Haase
CNT
thread
Ceramics
Glass
Tether Materials Zone
CNT
Graphene
hBN BNNT
New materials are strong and light enough to make this a reality

56. NASA Institute for Advanced Concepts
(NIAC) study
Dr. Edward’s excellent feasibility study and
book concluded that only one material was
strong enough to be a candidate for the tether
Carbon nanotubes
Since the feasibility study was published
materials science has been developing.
There are other candidate materials now…
Edwards. B, (2003) The Space Elevator NASA Institute for Advanced Concepts (NIAC) Phase II Final Report
http://images.spaceref.com/docs/spaceelevator/521Edwards.pdf

57. Images credit: Adrian Nixon created using Samson-Core molecular modelling
Boron Carbon Nitrogen
Graphene and hexagonal boron nitride (hBN)
Graphene
2D material
(130 GPa)
hexagonal boron
nitride (hBN)
2D material
(100 GPa)

58. Carbon nanotubes (CNT)
and Boron nitride nanotubes (BNNT)
Boron Carbon Nitrogen
Images credit: Adrian Nixon created using Samson-Core molecular modelling
CNT
(77 to 200 GPa)
BNNT
(30 to 159 GPa)
Sources:
Bedi, D., Sharma, A., Sharma, S. and Tiwari, S. (2022). Molecular Dynamics Simulation of
Carbon and Boron Nitride nanotubes: Tensile and Compressive Behavior. IOP conference
series, 1248(1), pp.012101–012101. doi:https://doi.org/10.1088/1757-899x/1248/1/012101.

59. Candidate tether materials for the space elevator
Single crystal
graphene
2D material
(130 GPa)
Single crystal
carbon nanotubes
(CNT)
1D material
(77 to 200 GPa)
Single crystal
hexagonal boron
nitride (hBN)
2D material
(100 GPa)
Key Carbon Boron Nitrogen
Single crystal
hexagonal boron
nitride nanotubes
(BNNT)
1D material
(30 to 159 GPa)

60. This is so new even the
descriptive language is evolving…
Single Crystal Graphene is one layer of graphene
Multiple layers of Single Crystal Graphene
make a new kind of material,
a form of coherent synthetic graphite
we will not have seen before:
A van der Waals Homostructure
Graphene Super-Laminate (GSL)
ISEC are already calling this multi-layered tether material
Graphene Super Laminate (GSL) even before it has been made

61. Sources :
CNT : ISEC studies based on “Space Elevators : An Assessment of the Technological Feasibility….”, IAA 2013
GSL : A. Nixon, July 2018 : atomic layer separation = 0.34 nm
CNT = Carbon Nanotubes
CNT Target GSL
Yield Strength 49.3 GPa 124 GPa
Density 1300 kg m-3 2260 kg m-3
Specific
Strength
37.9 MYuri 54.5 MYuri
Young’s
Modulus
1000 GPa 1000 GPa
Comparison with target : MATERIAL PROPERTIES
Graphene Super Laminate (GSL)

62. Graphene Super Laminate (GSL)
CNT Target GSL
Tether Thickness at Earth
Port
10.5 micron 4.2 micron
12,333 atomic layers
Tether Thickness at GEO 64 micron 14.7 micron
43,167 atomic layers
Taper Ratio 6:1 3.5:1
Total Tether Mass 6540 tonnes 2740 tonnes
Apex Anchor Mass 1900 tonnes 1455 tonnes
Working Stress 35.2 GPa 88 GPa
Nominal Strain 3.5 % 8.8 %
Based on calculations by J Knapman and P Robinson
Impact on Earth Space Elevator Design
No change in climber loads or safety margin (40%),
Tether dimensions : 100,000 km long x 1m wide

63. How might a space elevator tether be
constructed from Graphene Super Laminate?

64. Feasibility of
building the
tether…
• How big is a reel of single
crystal graphene 100,000km
long?
• 20mm core
• 1000mm wide
• 300mm Diameter
• How much would it weigh?
• 77kg

65. Combine the tether layers in orbit…
A GSL
Tether
Single Crystal
Graphene layers

66. Combine the tether layers in orbit…
Single crystal graphene
roll cassettes
Pinch rolls forming
Graphene super laminate tether

67. What the
tether looks
like
A thin sliver flat ribbon between
500mm to 1500mm wide
12,333 layers of graphene
4.2 microns thin
will support seven 20 tonne
climbers spaced at regular
intervals

68. So much for the theory
can tether materials be made at industrial scale?

69. Graphene currently
manufactured as powders
Commercial applications
starting to evolve
Single layer film graphene on metal foil
Two types of graphene manufacturing
Sheet or Film graphene is a far higher value market
Defect free sheet graphene is the ideal graphene film
and is called Single Crystal Graphene
2cm
Graphene Powder and Sheet/
Film

70. Laboratory scale manufacturing
of graphene and carbon nanotubes
Carbon nanotube forest
Graphene monolayer
Carbon containing feedstock gas,
in this case methane (CH4)
Copper or Nickel
metal catalyst
1000°C
The metal acts as a catalyst and substrate enabling the carbon
material to form and providing a platform for growth
Iron / Gadolinium / Aluminium
oxide (Fe/Gd/Al2O3) catalyst
750°C
Source:
Sugime, H., Sato, T., Nakagawa, R., Hayashi, T., Inoue, Y. and Noda, S., 2021. Ultra-long carbon nanotube forest
via in situ supplements of iron and aluminum vapor sources. Carbon, 172, pp.772-780.

71. Industrial scale graphene manufacturing by the roll-to-roll
chemical vapour deposition process can make large-area
sheet graphene
The annealing zone
conditions the metal
foil prior to graphene
formation
The growth zone forms
the graphene crystal
domains on the surface
of the metal
Large-area
sheet
Graphene on
metal foil roll
Bare metal foil roll
Annealing
Zone
Growth Zone
Continuous processes like this can
manufacture polycrystalline graphene
Manual processes
dissolve the metal
carrier and sheets of
freestanding graphene
hundreds of square
centimetres stacked up
to 30 layers thick have
already been made

72. CVD graphene now mass produced at a speed of
two metres per minute and in lengths of one kilometre
Vol 6 iss 6
Charmgraphene can make CVD
sheet graphene at:
• Speed of 2metres per minute
• Lengths up to 1kilometre
• On copper foil 300 mm wide
LG can make CVD
sheet graphene at:
• Speed of 1 metre
per minute
• Lengths up to
1kilometre
• On copper foil
400 mm wide
Graphene roll to roll transfer to polymer film, Image credit: You Tube and CharmGraphene
Source:
https://nano.market/news/graphene/charmgraphene-starts-mass-producing-cvd-graphene-using-a-roll-to-roll-process/
https://www.youtube.com/watch?v=NcTPjBIAbGE [Accessed 29th May 2022]
Graphene roll to manufacture Image credit: LG

74. Is a tether made from graphene
feasible?
Graphene is already being made at scale
300 to 400mm wide
in lengths of up to 1 Kilometre
at speeds if up to 2 metres per minute
YES
Graphene tether material really is possible within our lifetimes.

75. Space Elevator Tether
Single crystal sheet graphene sheet is strong enough
To make this a reality

76. https://www.sciencenews.org/article/japan-has-launched-miniature-space-elevator
Obayashi Corporation
Launched two
CubeSats to test a
small-scale tether
in 2018
This experiment was
deployed from the
International Space
Station ISS
A miniature tether and
climber has been
tested in low Earth orbit

77. Dual access to space: It needs to be a partnership
Rockets get people to space
fast
The space elevator can lift large amounts of mass
with no atmospheric pollution
Image credit: Galactic Harbour Associates
Image credit: HAZE

79. A final thought about the impossible…

80. The NewYorkTimes’ Editorial Prediction 1903
https://www.nytimes.com/1903/10/09/archives/flying-machines-which-do-not-fly.html
Hence, if it requires, say, a thousand years to fit for easy flight a bird which started with
rudimentary wings, or ten thousand for one with started with no wings at all and had to
sprout them ab initio, it might be assumed that the flying machine which will
really fly might be evolved by the combined and continuous efforts of
mathematicians and mechanicians in from one million to ten million years–
provided, of course, we can meanwhile eliminate such little drawbacks and
embarrassments as the existing relation between weight and strength in inorganic
materials. No doubt the problem has attractions for those it interests, but to the ordinary
man it would seem as if the effort might be employed more profitably. [emphasis added]
On the 17th December 1903 — about nine weeks after the Times‘
editorial — Orville and Wilbur Wright made the first controlled,
sustained flight of a powered heavier than air aircraft, the Wright Flyer,
at Kitty Hawk, North Carolina, with their plane, the Wright Flyer.
Flying Machines Which Do Not Fly

81. Rob Whieldon & Adrian Nixon
Thank you for your time
Happy to answer any questions
From Pencils and Scotch tape to the Space Elevator
rob@nixenepublishing.com adrian@nixenepublishing.com