2000 April 13, SPS 1020 (Introduction to Space Sciences) - Reading: today was PBD Chs. 15 & 16 - Read PBD Chs. 19, 21, & 22 for Tuesday, April 18. - Read TNSS 27 & 28 and PBD 5 & 20 by Thursday, April 20. --------------- Spaceflight Present ------------------- Just in case you think progress in space isn't as rapid as in the glory days of Apollo, remember: more people go into orbit every year than during the entire 1960s. Launch systems now in service: U.S.A.(national agency, NASA; several private companies supplying boosters): ------ Space Shuttle: now operated commercially, by United Space Alliance (consortium of Lockheed-Martin and Boeing) Expendable boosters: - Delta II (Boeing) - smallest (new: Delta III, Delta IV) - Atlas 2AS (Lockheed-Martin) - mid-sized (new: Atlas 3) - Titan 4 (Lockheed-Martin) - largest current U.S. booster Descended from military missiles developed in `50s. All were to have been phased out in the `80s, but were revived after the Challenger disaster. Not very competitive, commercially: U.S. needs to develop new boosters. Newer boosters: - Athena (Lockheed-Martin): all-solid booster, small-to-mid-sized - Pegasus (Orbital Sciences Corp.): aircraft-launched, for small satellites Europe (gov't-run European Space Agency; Arianespace private company): ------ ESA member states: Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, The Netherlands, Norway, Spain, Sweden, Switzerland, United Kingdom, Canada (!) - Ariane 4: highly successful, now has 2/3 of commercial market share. Developed in `80s specifically for commercial use; launches from equator, in Guyana (site: Kourou). - Ariane 5: new large booster, competitive with Titan 4 China: Long March rocket: snapping up market share of commercial launches! ----- Shen-Zhou MANNED spacecraft: modified Soyuz, bought from Russia Tested unmanned last year. Manned flights soon? China will soon enter an exclusive club of nations (USA, USSR). Japan (2 agencies, NASDA and ISAS): ----- H-I, H-II boosters uncharacteristically lost money, unlikely to be competitive. Also bad failure with ASTRO-E launch this year; also problems with fishing fleet. But are starting an impressive planetary program (Nozomi to Mars, Lunar A, MUSES-A to the Moon in 1990). Again, Japan is now in an exclusive club of nations (USA, USSR, ESA). Israel, India, Pakistan not yet offered as commercial: they're weapons ----------------------- Russia (Russian Space Agency; Energia private company): ------ - R-7: nearly 2000 have been launched, well-proven and reliable - Proton: Titan-class For both: have agreed, as part of $400M Mir deal, not to undercut U.S. - Soyuz crew capsules, Progress robot freighters; both carried by R-7. - Energia? Saturn V-class heavy-lift boster (100 tons to LEO) Flew once in 1986; once again in 1988 with Buran, Soviet shuttle. Some myths about the Saturn V: ----------------------------- - Urban legend: the plans were lost. The plans are where they've always been, on microfilm at NASA Marshall. - Then why don't they bring the Saturn V back? 1) Do you know how hard it is to keep a car that old running? Where do you get parts, including mid-`60-s technology pumps, valves, and gyroscopes? By the time you bring back all that, you might as well have designed an all-new vehicle. 2) Both Saturn V pads, 39-A and 39-B at KSC on Merritt Island (across the Banana River from Cape Canaveral, which wasn't big enough to hold them), have been modified extensively to launch the Space Shuttle. You therefore have nowhere to launch from. 3) Most importantly: To do what? To fly what missions? With what money? If there is a real need for a heavy-lift vehicle (e.g., for human flights to Mars), it would make more sense to develop a shuttle-derived heavy-lift vehicle, e.g., the Ares booster proposed by R. Zubrin in The Case for Mars. Spaceflight Future ------------------ - International Space Station (ISS): scheduled to be finished in 2004. --------------------------- $30 billion construction cost; $108 billion total cost, over 15 years. Primary purposes: 1) Studies of the long-term effects of micro-g (formerly called weightlessness) on the human body. This only really makes sense, though, if there is a need to know it: like, for example, human flights to Mars... Careful, though: Congress in 1969 refused to fund a space station because they saw it as a piecemeal way of sending astronauts to Mars. 2) Studies of effects of micro-g on crystal growth, pure substance manufacture, alloys, & other processes. Commercial interest has so far not been enthusiastic: space manufacturing, and freight, are expensive! (Alternatives made on ground are MUCH cheaper.) 3) International diplomacy: useful way to employ Russian _and_ U.S. aerospace industries. We are winding down from a long arms race, the Cold War. History shows many examples of a war or arms race leaving behind so many weapons, another war started, e.g. 100-Years War => Wars of the Roses in England; Samurai warrior caste that arose in the 100-years civil wars in medieval Japan eventually caused WWII. - A space station is NOT GREAT for astronomy or Earth observation: astronauts jiggle pointing, contaminate environment. (Still, I'd like to try a small automatic, ultraviolet telescope...) - Also, an on-orbit satellite assembly and servicing facility (in my mind, the most interesting things that a space station would be good at): was not funded. (Wasn't necessary for Moon, but might be for Mars.) ISS has often been criticized by the scientific community. They see it as too expensive for the science it will do---much of which can be done more cheaply, and often better, with robot spacecraft. e.g., Skylab cost $2.5 billion, or $15 million/day for 3 astronauts. Can you do $5 million worth of science in a day? $2.5 billion, could have run the entire National Science Foundation (supporting astronomy, physics, chemistry, bio, all fields) for 4 years! This misses the point, though. While some science will get done aboard ISS, some of it even interesting, ISS *isn't* primarily about science, no more than Apollo or the Shuttle were. It's mainly about technology development: Can we learn how to live, work, and build things in space? BIG problem: Congress and the U.S. public don't know the difference between science and technology. Therefore, every time ISS has a cost over-run, it's taken out of the science budget. NASA and the science community would get along MUCH better if this didn't happen. Also: When scientists complain about ISS's cost, they seem to think that if it were cancelled, its budget would go into the science budget. This is naive, and just plain false. Indeed, science funding would probably suffer: Viking and Voyager almost certainly wouldn't have happened if Apollo hadn't. The money for Galileo and Hubble wouldn't have appeared in the absence of the Shuttle---but then, they could have been launched on Titan 4 boosters...(But not repaired!) Another thing scientists don't like about ISS something you should avoid: some of its advocates make promises it can't keep. For example, the cure for AIDS will likely be found in some medical lab that's looking for it---NOT on ISS. (ISS advocates sometimes stoop to these arguments because they can't explain the real reasons to Congress or the public in ways they understand. I think this means they have to work on making their explanations easier to understand. It doesn't excuse intellectual dishonesty: nothing does.) NEEDED BADLY for ALL future space programs: ------------ --- A MUCH cheaper way to get into space. Space Shuttle costs about $20,000/kg! ($10,000/lb) One shuttle flight costs about $1 billion. Shuttle program's budget is $6 billion/year, with about 6 flights/year, although people argue about this. => Anything going up into, or down from, space has to be literally worth its weight in gold to be profitable. Communication satellites are profitable, but their signals up and down weigh nothing. Manufactured goods are not profitable, so far. - The X-33 and Venturestar: Shuttle replacement, by Lockheed ------------------------ (X-33 = 1/3-scale prototype; Venturestar = operational vehicle) Objective: to reduce cost of spaceflight by a factor of 10. All-reusable, single-stage-to-orbit vehicle. See October 1997 Scientific American, p. 120, for detailed article X-33 is now having problems with its LH2 tank, though, and may not be close to flying, although the schedule is for first launch in 2002. See also February 1999 Scientific American, p. 80, for article on other vehicles and transportation methods under development, e.g.: - Roton Rotary Rocket - U.S. Air Force's Solar Orbit Transfer Vehicle - Air-breathing engines (National Aerospace Plane [NASP] cancelled in 1992: not feasible with present technology, costs spiraled out of control) - Others, but then I've seen plenty come and go, over the years... - X Prize: $10 million offered (half already raised) for anyone who can privately fund and construct a vehicle that can fly 3 people over 100 km altitude, and be ready to fly again within 2 weeks. 16 teams now in competition. (Charles Lindbergh flew the Atlantic solo for a similar prize.) - Human Mars Expeditions: ---------------------- - Current NASA baseline mission: $50 billion (3 human missions, crew of 6) (article in Popular Science, 1999 February, p. 40) - The Case for Mars, by Robert Zubrin: Mars Direct: estimated cost $20-30 billion (2 human missions with crew of 4 each, 3 automated cargo landers, spread over 6 years). Depends critically on using the atmosphere of Mars, both for rocket braking (aerobraking) and for making fuel for return trip. Bring some H_2, and do this: H_2 + 4 CO_2 -> CH_4 + 2 H_2 O (the Sabatier reaction) The methane is useful for rocket fuel. The water is useful for showering. R. Zubrin has tested this, and NASA plans to test it on an upcoming lander, on Mars. Problem: riskier. Mars Direct would fly directly from Earth's surface to Mars's surface: no chance for vehicle check-out in Earth or Mars orbit. Both plans: 6 months out, 6 months back, must spend 500 days at Mars, to wait for next opposition (closest approach) to Earth. - Deimos: This Martian satellite is in a 30-hour orbit, nearly synchronous with planet. (Martian day is 24 hours, 37 minutes long). => Useful observation & communications post. Also useful fuel depot: Deimos is made of carbonaceous material, rich in volatiles, especially water => Can make rocket fuel (H_2, with O_2 oxidizer). May also be useful command post for teleoperated vehicles (rovers, balloons, and airplanes). Fred Singer's paper at the original 1984 Case for Mars conference: Suggested mission with an "Apollo 10" dress rehearsal, humans NOT to land on Mars. (Should make sure one could get back, before going down to strange planet after getting weaker in micro-g for many months.) Would STILL get lots of Mars science, though, since for the 500 days the crew would have to stay at Deimos, they could work with teleoperated vehicles on Mars: since nearby, wouldn't have the 20-minute and longer delays Mars Pathfinder had. (How many of you would go on this mission?) (Compare with how many would go on a mission to land on Mars.) Zubrin has promised to lobby the U.S. president elected in 2000, hard. Is setting up $12M prototype Mars habitat on Devon Island, Canada, near Haughton Crater (see 1999 July National Geographic). - Expeditions to Near-Earth Asteroids: ----------------------------------- Advocated by Sagan, was possible with Apollo hardware, could be done with Mars expedition hardware. Much of science might be done on Deimos, but time-of-flight may be days, not months or years. => Useful for testing Mars equipment? Moon may NOT be: Zubrin argues it would be a diversion. - Satellite Communications (in 24-hour, geostationary orbits): ------------------------ Over next 10 years, over 600 new comsats are planned---about 1 per week! => May result in: - Return to the Moon: ------------------ Delta-v---meaning energy, and therefore cost---required to get to Moon is comparable to that for GEO. (Actually, it's slightly less.) An Orbital Transfer Vehcile (OTV, or space tug) using aerobraking to get back into LEO would have an even larger advantage. => Once you become able to send astronauts to GEO, to service or assemble large, complex communications satellites, you become able to go to the Moon. (Put legs on OTV and dust-proof it: that regolith is dusty.) Realized in mid-'80s by Wendell Mendell, had _great_ conference. Proceedings: Lunar Bases and Space Activities of the 21st Century (in Evans library). Apollo: every mission cost $2 billion (current dollars). 2 missions/year => $4-6 billion/year, including infrastructure. Space Shuttle program costs $6 billion/year. NASA's budget is $14 billion/year. => Moon base with Apollo hardware would be a strain on NASA's budget. (NASA's budget is about 5% of the defense budget; defense budget is less than the budget for social programs. Therefore, totally abolishing NASA wouldn't solve many social problems.) The current U.S. Antarctic program is now funded at $300 million/year (about as much as a large national lab, or a major research university: Florida Tech, a small school, has a $62 million annual budget). This includes two bases (South Pole & McMurdo), transport, and logistics. => If a Moon base could be done for 3-5 times this ($1-2 billion/year), it might happen, since there _would be_ sufficient scientific justification for it. - Moon would be great for geology and studies of solar system history. - Would also be great site astronomical telescopes, and especially interferometers (clusters of telescopes synched together to produce unbelievably high resolution). Also, Moon is radio-quiet on Far Side; also, there is perpetual darkness at the bottoms of craters at the North and South Poles, for the same reason they are otherwise of interest. (What reason, and why?) Moon has readily available building materials: - Concrete. Add water to regolith, found by Portland Cement Co. to make a strong, radiation-resistant concrete. It's a good thermal insulator, too. - Glass. Some Apollo 17 regoliths > 75% glass. This isn't ore, this is ready-to-use material! - High-grade stainless steel, from Fe-Ni meteorites. Again, nearly ready to use. - Aluminum. Would have to extract from rocks at high T, though. (Solar concentrators.) Oxygen (O_2) would be a by-product of this process. => Exporting OXYGEN, of all things, might be profitable! Two-thirds of the mass of a spacecraft going from LEO to GEO (and further) is O_2, for propellant. Moon's escape velocity = 2 km/s, versus Earth's = 11 km/s. This would greatly reduce cost of spacecraft to GEO and further, once the infrastructure was built. - Another essential resource: WATER Recent discovery of ice at lunar poles (Clementine, 1994; Lunar Prospector, now). Makes living on Moon MUCH more practical! Best site: the Mountain of Eternal Light, at the S. Pole. May also revolutionize economics of interplanetary flight, since this source of rocket fuel (H_2 and O_2) is in the Moon's weak gravity.