All about spacecraft and spaceflight
اسلاید 1: 29 Sept 03 Solar System - Dr. C.C. Lang1Exploring the Solar System: all about spacecraft/spaceflightHow do we get there? - launch & orbits- gravity assist- fuel/propulsionHow can we explore the Solar System?- types of space missionsIII. Onboard Systems- everything but the kitchen sink…
اسلاید 2: 29 Sept 03 Solar System - Dr. C.C. Lang21. 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)
اسلاید 3: 29 Sept 03 Solar System - Dr. C.C. Lang3Famous 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 2020Clouds on NeptuneInterplanetary Space & the Solar Wind
اسلاید 4: 29 Sept 03 Solar System - Dr. C.C. Lang4Other 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)
اسلاید 5: 29 Sept 03 Solar System - Dr. C.C. Lang5Future 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
اسلاید 6: 29 Sept 03 Solar System - Dr. C.C. Lang62. 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
اسلاید 7: 29 Sept 03 Solar System - Dr. C.C. Lang7Famous 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 moonsBurned up in Jupiter’s atmosphere last week!
اسلاید 8: 29 Sept 03 Solar System - Dr. C.C. Lang83. 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 missionExample: Galileo’s atmospheric probe
اسلاید 9: 29 Sept 03 Solar System - Dr. C.C. Lang9Example: 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
اسلاید 10: 29 Sept 03 Solar System - Dr. C.C. Lang104. Lander Spacecraft- designed to reach surface of a planet/body- survive long enough to transmit data back to Earth- small, chemical experiments possibleMany Successful Examples: - Mars Viking Landers- Venus Lander- Moon Landers (with humans!)Mars VikingLander
اسلاید 11: 29 Sept 03 Solar System - Dr. C.C. Lang11Example: NEAR Asteroid Rendevous MissionNear-Earth Asteroid Erosfly to a nearby asteroid: Eros – 1-2 AU orbit around Sun~ twice size of NYC
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اسلاید 14: 29 Sept 03 Solar System - Dr. C.C. Lang145. 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 surfaceNo 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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اسلاید 16: 29 Sept 03 Solar System - Dr. C.C. Lang166. 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 developedMars PathfinderMars Exploration Rovers
اسلاید 17: 29 Sept 03 Solar System - Dr. C.C. Lang177. Observatory Spacecraft- in Earth orbit (or at Lagrange points)- NASA’s “Great Observatories”: - Hubble (visible)- Chandra (X-ray)- SIRTF (infrared)- Compton (gamma-rays)Large, complex scientific instruments- up to 10-20 instruments on board- designed to last > 5-10 yearsSIRTF (near-IR)Chandra (X-ray)SOHO
اسلاید 18: 29 Sept 03 Solar System - Dr. C.C. Lang18How do we get there?1. First must leave the Earth’s surface- must ‘escape’ into orbit- gets an initial boost via rocketto go into Earth’s orbit – needsan acceleration of 5 miles/sec- during orbit, you sometimes need to adjust height of orbitby increasing/decreasing energy:- practically: firing onboard rocketthrusters- a speed of 19,000 miles/hrwill keep craft in orbit around Earthusing LEAST amount offuel – saves big $$$ to be light
اسلاید 19: 29 Sept 03 Solar System - Dr. C.C. Lang19How do we get there?2. To get to an outer orbit: Mars- spacecraft already in orbit (around Sun)- need to adjust the orbit – boost via rocket –so that the spacecraft gets transferred fromEarth’s orbit around Sun to Mars’ orbit around Sun- but you want spacecraft to intercept Mars onMars’ orbit- matter of timing: small window every 26 months- to be captured by Mars – must decelerate- to LAND on Mars – must decelerate further &use braking mechanismusing LEAST amount offuel – saves big $$$ to be light
اسلاید 20: 29 Sept 03 Solar System - Dr. C.C. Lang20How do we get there?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 onVenus’ orbit- matter of timing: small window every 19 monthsusing LEAST amount offuel – saves big $$$ to be light
اسلاید 21: 29 Sept 03 Solar System - Dr. C.C. Lang21How do we get there?4. Gravity Assist- can use the law of gravity to help spacecraftpropel themselves further out in the SS- Voyager: its trajectory was aimed at gettingto Jupiter’s orbit just after Jupiter- Voyager was gravitationally attracted toJupiter, and fell in towards Jupiter- Jupiter was “tugged on” by Voyager and itsorbital energy decreased slightlythen Voyager had more energy than wasneeded to stay in orbit around Jupiter, andwas propelled outward!- repeated at Saturn & Uranususing LEAST amount offuel – saves big $$$ to be light
اسلاید 22: 29 Sept 03 Solar System - Dr. C.C. Lang22At 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.
اسلاید 23: 29 Sept 03 Solar System - Dr. C.C. Lang23How do we get there?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 shortbursts from its thrusters to make adjustments- mostly free falling in orbit, coasting to destinationusing LEAST amount offuel – saves big $$$ to be light
اسلاید 24: 29 Sept 03 Solar System - Dr. C.C. Lang24How do we get there?5. The Future: Ion Propulsion- Xenon atoms are made of protons (+) and electrons (-)- bombard a gas with electrons (-) to change charge- creates a build up of IONS (+)- use magnetic field to direct charged particles- the IONS are accelerated out the back of craft- this pushes the craft in the opposite directionusing LEAST amount offuel – saves big $$$ to be light
اسلاید 25: 29 Sept 03 Solar System - Dr. C.C. Lang25to operate the ion system, use SOLAR panelssometimes called solar-electric propulsioncan push a spacecraft up to 10x that of chemical propulsionvery gentle – best for slow accelerations
اسلاید 26: 29 Sept 03 Solar System - Dr. C.C. Lang26HISTORY 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
اسلاید 27: 29 Sept 03 Solar System - Dr. C.C. Lang27Europe’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!**
اسلاید 28: 29 Sept 03 Solar System - Dr. C.C. Lang281. data handling 2. flight control 3. telecommunications 4. electrical power 5. particle shields 6. temperature control7. propulsion mechanism 8. mechanical devices (deployment)Onboard Systems on Most Spacecraft: Galileo
اسلاید 29: 29 Sept 03 Solar System - Dr. C.C. Lang29Time & Money ConsiderationsPlanning 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 rateCosts! (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.
اسلاید 30: 29 Sept 03 Solar System - Dr. C.C. Lang30This powerpoint was kindly donated to www.worldofteaching.comhttp://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.
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