This document discusses different types of spacecraft and space missions used to explore the solar system. It describes flyby missions like Voyager that pass by planets to study them without entering orbit. Orbiter spacecraft like Galileo are designed to enter a planet's orbit to study it up close for an extended period. Atmospheric probes and landers allow studying a planet's surface and atmosphere. Future technologies like ion propulsion could enable slower but more fuel efficient missions. Successfully exploring the solar system requires careful planning of spacecraft design, trajectories, and within budget constraints that can exceed $100 million per mission.

1. Exploring the Solar System:
all about spacecraft/spaceflight
I. How can we explore the Solar System?
- types of space missions
II. How do we get there?
- launch & orbits
- gravity assist
- fuel/propulsion
III. Onboard Systems
- everything but the kitchen sink…
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2. 1. Flyby Missions
• usually the first phase of exploration
(remember Mars & Mariner 4?)
• spacecraft following continuous orbit
- around the Sun
- escape trajectory
(heading off into deep space)
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3. Famous Example: VOYAGER 2
- launch 1977 with VOYAGER 1
- flew by Jupiter in 1979
- Saturn in 1980/1981
- Uranus (V2) in 1986
- Neptune in 1989
- will continue to interstellar space
- study of interplanetary space particles (Van Allen)
- data expected until 2020
Clouds on Neptune
Interplanetary
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4. Other Flyby examples:
Underway: Stardust Comet return mission
- launched in 1999
- interstellar dust collection
- asteroid Annefrank flyby
- Comet encounter (Jan 2004)
- Earth/sample return (Jan 2006)
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5. Future flyby: Pluto-Kuiper Belt Mission
- to be launched in January 2006
- swing by Jupiter (gravity assist*)
- fly by Pluto & moon Charon in 2015
- then head into Kuiper Belt region
(tons of solar system debris)
- to study objects that are like Pluto
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6. 2. Orbiter Spacecraft
• designed to travel to distant planet &
enter into orbit around planet
• must carry substantial propulsion
(fuel) capacity has to withstand:
- staying in the ‘dark’ for periods of time
- extreme thermal variations
- staying out of touch with Earth for periods of
time
• usually the second phase of
exploration
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7. Famous Example: Galileo
- why would a mission to Jupiter be called Galileo?
- launched in 1989 aboard Atlantis Space Shuttle
- entered into Jupiter’s orbit in 1995
- highly successful study of Jupiter & its moons
Burned up in Jupiter’s atmosphere last week!
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8. 3. Atmospheric Spacecraft
- relatively short mission
- collect data about the atmosphere of a planet or planet’s moon
- usually piggy back on a bigger craft
- needs no propulsion of its own
- takes direct measurements of atmosphere
- usually is destroyed; rest of spacecraft continues its mission
Example:
Galileo’s atmospheric probe
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9. Example: Galileo’s atmospheric probe
- traveled with Galileo for nearly six years
- took five months from release to contact with atmosphere
- collected 1 hour’s data IN Jupiter’s atmosphere
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10. 4. Lander Spacecraft
- designed to reach surface of a planet/body
- survive long enough to transmit data back to Earth
- small, chemical experiments possible
Mars Viking
Lander
Many Successful Examples:
- Mars Viking Landers
- Venus Lander
- Moon Landers
(with humans!)
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11. Example: NEAR Asteroid Rendevous Mission
fly to a nearby asteroid: Eros – 1-2 AU orbit around Sun
Near-Earth Asteroid Eros
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~ twice size of NYC
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14. 5. Penetrator Spacecraft
- designed to penetrate the surface of a planet/body
- must survive the impact of many times the gravity on Earth
- measure properties of impacted surface
No Currently Successful Examples:
- Deep Space 2 (lost with Mars Polar Lander)
But more to come in future:
- “Ice Pick” Mission to Jupiter’s Moon Europa
- “Deep Impact” Mission to a Comet
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16. 6. Rover Spacecraft
- electrically powered, mobile rovers
- mainly designed for exploration of Mars’ surface
- purposes: taking/analyzing samples with possibility of return
- Pathfinder was test mission – now being heavily developed
Mars Pathfinder
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Mars Exploration Rovers
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17. 7. Observatory Spacecraft
- in Earth orbit (or at Lagrange points)
- NASA’s “Great Observatories”:
- Hubble (visible)
- Chandra (X-ray)
- SIRTF (infrared)
- Compton (gamma-rays)
SOHO
-Large, complex scientific instruments
- up to 10-20 instruments on board
- designed to last > 5-10 years
SIRTF (near-IR)
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Chandra (X-ray)
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18. How do we get there?
using LEAST amount of
fuel – saves big $$$ to be light
1. First must leave the Earth’s surface
- must ‘escape’ into orbit
- gets an initial boost via rocket
to go into Earth’s orbit – needs
an acceleration of 5 miles/sec
- during orbit, you sometimes
need to adjust height of orbit
by increasing/decreasing energy:
- practically: firing onboard rocket
thrusters
- a speed of 19,000 miles/hr
willSept 03 in orbit around Earth
keep craft
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19. How do we get there?
using LEAST amount of
fuel – saves big $$$ to be light
2. To get to an outer orbit: Mars
- spacecraft already in orbit (around Sun)
- need to adjust the orbit – boost via rocket –
so that the spacecraft gets transferred from
Earth’s orbit around Sun to Mars’ orbit around Sun
- but you want spacecraft to intercept Mars on
Mars’ orbit
- matter of timing: small window every 26 months
- to be captured by Mars – must decelerate
- to LAND on Mars – must decelerate further &
useSept 03 mechanism Solar System - Dr. C.C. Lang
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20. How do we get there?
using LEAST amount of
fuel – saves big $$$ to be light
3. To get to an inner orbit: Venus
- spacecraft already in orbit (around Sun) on Earth
- need to adjust the orbit once off Earth to head
inwards to Venus
- instead of SLOWING down (you’d fall to Earth),
you use reverse motion in your solar orbit, effectively
slowing down to land on Venus’ orbit
- but you want spacecraft to intercept Venus on
Venus’ orbit
- matter of timing: small window every 19 months
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21. How do we get there?
using LEAST amount of
fuel – saves big $$$ to be light
4. Gravity Assist
- can use the law of gravity to help spacecraft
propel themselves further out in the SS
- Voyager: its trajectory was aimed at getting
to Jupiter’s orbit just after Jupiter
- Voyager was gravitationally attracted to
Jupiter, and fell in towards Jupiter
- Jupiter was “tugged on” by Voyager and its
orbital energy decreased slightly
-then Voyager had more energy than was
needed to stay in orbit around Jupiter, and
was propelled outward!
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- repeated at Saturn & Uranus
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22. At what speeds are these things traveling through space?
The currently fastest spacecraft speeds are
around 20 km per second (72,000 km per/hr)
For example, Voyager 1 is now moving
outwards from the solar system at a speed of
16 km per second. At this rate, it would
take 85,000 years to reach the nearest star
-3,000 human generations!
Even assuming that we could reach a speed
of 1/10th of the velocity of light, it would
still take a minimum of 40 years or so to
reach our nearest star.
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23. How do we get there?
using LEAST amount of
fuel – saves big $$$ to be light
5. Concerns about energy sources
- traditional energy boost: chemical thrusters
- most of energy is provided on launch – very costly!
especially for large, heavy, complex instruments
- a few times per year spacecraft fires short
bursts from its thrusters to make adjustments
- mostly free falling in orbit, coasting to destination
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24. How do we get there?
using LEAST amount of
fuel – saves big $$$ to be light
5. The Future: Ion Propulsion
- Xenon atoms are made of protons (+) and electrons (-)
- bombard a gas with electrons (-) to change charge
- creates a build up of IONS (+)
- use magnetic field to direct charged particles
- the IONS are accelerated out the back of craft
- this pushes the craft in the opposite direction
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25. •
•
•
•
to operate the ion system, use SOLAR panels
sometimes called solar-electric propulsion
can push a spacecraft up to 10x that of chemical propulsion
very gentle – best for slow accelerations
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26. HISTORY of ION PROPULSION
• first ion propulsion engine – built in 1960
• over 50 years in design/development at NASA
• very new technology
• has been used successfully on test mission:
Deep Space 1
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27. Europe’s Lunar Explorer: Smart 1 Probe
- launched 27 September 2003 (Saturday)
- 2-2.5 year mission
- will study lunar geochemistry
- search for ice at south Lunar pole
- **testing/proving of ion propulsion drives!**
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28. Onboard Systems on Most Spacecraft: Galileo
1. data handling
2. flight control 3. telecommunications
4. electrical power 5. particle shields
6. temperature control
7. propulsion mechanism System - Dr. C.C. Lang
8. mechanical devices28
(deployment)
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Solar

29. Time & Money Considerations
Planning for a new spacecraft
- plans start about ~10 years before projected launch date
- must make through numerous hurdles/reviews
- very competitive: 1/10-25 average acceptance rate
Costs! (circa 2000) – total NASA budget (2000) was $13 billion
• Basic Assumptions for design/development of small craft:
- Cost of spacecraft and design: $50M
- Cost of launch: $50M + $10M per AU + $10M per instrument
- Cost of mission operations: $10M / month
- Initial speed: 3 months per AU of distance
For every additional instrument, add $100M and increase travel time by 25%
(e.g., for four instruments, double the travel time)
A probe, lander, or balloon counts as two additional instruments.
If you are going to the outer Solar System (Jupiter or beyond),
you must add plutonium batteries, which count as one instrument.
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30. This powerpoint was kindly donated to
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visit and I hope it will help in your teaching.
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