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NASA has no "coherent" RLV strategy. And, IMHO, NASA should have NO RLV strategy. Any RLV whose general design is dictated by NASA will be doomed to failure. If the Air Force and NASA get together to specify a vehicle, it will turn into another Shuttle debacle.
I think that NASA's answer will come, indirectly, from the X-Prize. Teams like Cosmopolis, DaVinci, Canadian Arrow, Star Chaser, Burt Rutan, Armadillo, and X-Cor all have tremendous potential. I feel that if any of these firms can tap into the suborbital space tourism market, an orbital spacecraft will certainly be developed. I also have optimism that the industry is looking at developing their own RLVs. A Boeing official once said that Delta IV would be Boeing's last RLV. A third route is DARPA, whose projects like RASCAL are inspiring the impossible.
Right now, NASA is struggling with scramjets and trying to determine whether they are worth NASA's time. Once the X-43 flies, you will see NASA's plans firm up. But I still think that NASA should stick to research and let the industry build and operate the vehicle.
Happy April Fools!
I really wish that Gates & company decided to invest in human spacefight. But the idea's been tried before and nothing came of it. Rand Simberg has asked the question of private investment to many people who have tried to win the X-Prize. One of these space visionaries (I believe it was Gary Hudson,) admitted that he's approached Bill Gates-types and been rejected. And yet Gary Hudson is the man who got Tom Clancy to fund his Rotary Rocket. So there are obviously a few wealthy people who are willing to support manned spaceflight with money, but the ones with the real funding, to make a man on Mars possible, just won't invest. The best strategy, after being rejected by the billionaires, is to woo a large number of millionaires.
The Russians also have an EELV in the works. Called "Angara," it's an attempt by Russia to move away from using launch facilities in Kazakhstan and factories in the Ukraine. Powered by one RD-191 engine per common booster core, it is available in clusters of one, three, and five. The Angara 5 Heavy can put 11.2 tonnes in GTO, just short of the Delta IV heavy. The most exciting development on the Angara front is a proposed flyback booster core with a scissor wing, sometimes referred to as "Baikal."
Another interesting "engineering editorial" about the shuttle with some applications to MAKS. I'd wonder, though, how MAKS would behave if you moved the engines onto its ET. It's important to note which engineering assumptions the author makes. He thinks that bending loads are fatal to the booster, but he agrees with the author to the original "Is the Shuttle Critically Flawed?" article that engines put too much stress on the orbiter. I see two fallacies in the article. First, the author dismisses the idea of flyback boosters, even though NASA has rejected the idea of liquid boosters that recover in the water. His other belief is that F-111 ejection capsules will work to save the crew, when the F-111 was one of the worst planes to eject from (and a similar system was tested and rejected for the B-1.) My only question is how the Buran protected its belly from ice damage when there was no foam on the Energia core. But I do agree with the basic premise of the article--Energia was a more versatile design. However, I think that the Buran orbiter was a mistake for similar reasons the shuttle was--too large a payload, too large a cross range.
Over the past year, Dr. Zubrin has twice been a guest on the popular "Coast to Coast" radio show. On one of these occasions, he sparred with RIchard C. Hoagland, the "rebel scientist" behind "The Enterprise Mission."
The question I pose is, do you think Dr. Zubrin should continue with radio appearances on this show? On the plus side, he's getting the Mars Society name out there and building support for our ideas. On the flip side, he may be discrediting the organization by appearing on a show that is noted for its sensationalism and its never-ending stream of crackpot guests. It's obviously a decision that has its benefits and risks. Which side outweighs the other?
Russia has long talked about air-launched vehicles using their monstrous AN-124/225 transports as a first stage, and MAKS is only one of many concepts. BURLAK was another air-launch concept that used a TU-160 as a mothership. So the system demanded by the Duma may not be MAKS after all. The problem I see with Russian industry is that their funding is nowhere close to a level that can support designers' creativity. I feel that only the Chinese defense buildup can save Russia's aerospace industry from ruin (and even so, the Chinese have indicated a preference to develop their own aircraft, spacecraft, and weapons systems in the future.) I'm very skeptical that the Russians can build an air-launch vehicle without outside money, and I think that we'll eventually see Russia partner with the ESA or become an ESA member to keep its industry alive (and give ESA the manned launch capability it lacks.)
The issue of Enrgia has been the focus point of many heated threads on this forum.
Essentially, the Energia argument breaks down to this: Energia was the greatest booster mankind built, short of the Saturn V (and better in some aspects, because it was a highly modular system.) It would be difficult and possibly costly to restart production because much of the tooling is gone and the infrastructure degraded. In the end, it all boilds down to whether a newer booster can be built to the same (or higher) specs as Energia for a similar cost as reconstituting the Energia system.
My suspicion is that it would be cheaper to build a HLLV from Delta IV or Atlas V components, because the booster cores and engines are in production, and the facilities to launch them are operating. A shuttle-derived vehicle, akin to Shuttle C or Zubrin's Ares, would be feasible, but it would be hindered by additional expenses like modifications to the hardware and launch infrastructure.
The "Heavy" versions of both Delta IV and Atlas V can launch around 25 tons. The problem is that Lockheed Martin has no firm plans for Atlas V heavy (three common booster cores in parallel.)
I don't think an economic case can be made anytime soon for a heavy lifter, but the cost of NASA purchasing a few HLLVs can be minimized if such an HLLV can be built by clustering components from smaller boosters that are already in production. My hope is that Boeing and Lockheed Martin will design larger clusters of Delta IV and Atlas V to use for future Mars missions.
If NASA operates the shuttle until 2020 (a proposition that I disagree with,) they will need to replace Columbia. It is impractical to re-open the shuttle production lines (it was hard enough with Endeavour, and even then many parts were built as backups for Discovery and Atlantis.) One option that has been lost is rebuilding Enterprise, which was considered before Columbia first flew. Enterprise is now part of the Smithsonian collection, and I doubt they will be too pleased about NASA taking it back after all the work that went into restoring it.
The best plan of action is for NASA to realize that the Shuttle cannot fly until 2020. The shuttle should be a museum piece by 2015, and until then it should only be flown on ISS construction missions that are absolutely necessary. Higher priority must be given to a reusable booster for the OSP, and for the OSP program in general.
Kourou is the ESA spaceport in French Guiana. It's practically on the equator, so it's probably the most ideal place to launch a rocket into orbit, from a delta-V standpoint.
Commercial Soyuz rockets wil be launching from Korou in the near future; it's not unreasonable to think that manned launches will be far behind.
The HL-20 is way too big. Since it would require a Delta IV Large to launch it, the launch vehicle would cost $170 million per launch. That makes it way too expensive. You are also falling into the trap of believing that if it hasn't already been done, it can't be done.
The HL-20 weighs only 17 tonnes, putting it in the range of a Delta-IV medium. Further, the eight-crew requirement only allows for astronauts sitting upright. Orbital Sciences has modified the design to accomodate a flight crew of two and three astronauts, allowing the astronauts to recline to a horizontal position as they return from a long-duration space mission. Clearly, the extra volume is necessary.
It's also incorrect to say the X-38 was developed from the HL-20 when, in fact, the X-38 is based on the X-24 shape. The X-38 was actually developed as a low-cost alternative to HL-20, using parafoil landing to keep size and weight down but sarcrificing the gliding landing.
GEO requires too much delta-V for a manned spacecraft--almost as much as a trip to the moon.
Relegating the space elevator to the future when it's more feasible, the aerospace industry (or whatever's left of it, following the mergers and defense cutbacks of the 1990's) should concentrate on developing a commercially successful, unmanned RLV.
The natural market niche for this RLV is replacing the most successful commercial launcher of all time--the McDD Delta II. Of course, this would mean developing a relaible system on-the-cheap and operating it at a significantly cheaper price. The only alternative is if NASA and the USAF got together and said they wanted a new way to launch payloads under 5.8 tonnes.
My hope is that all ELVs will eventually be replaced by partially or fully-reusable launchers, operated by for-profit companies. Eventually, these reusable rockets will be man-rated and perform a plethora of tasks in makind's quest to tame space.
Relocating the ISS into a lower inclination orbit would be a perfect test for a VASIMR thruster. The engine that gets us to Mars must be put through the wringer in a less demanding and closer-to-home way before it's ready to propel humans.
If ISS is moved, should it be moved to 28.5 degrees (allowing a shuttle, in its normal orbit, to dock at will,) or should it be put in equatorial orbit to synch up with RSA / ESA spacecraft?
NASA essentially has to choose between the HL-20 or the larger HL-42. The former was a 17 tonne lifting body with 4 tonnes of payload, the latter was a 31 tonne lifting body with 9.3 tonnes of payload. Because the HL-42 would require a new booster, it probably will not be pursued, although the HL-20 is more suited for launch on a smaller (and cheaper) variant of Atlas V or Delta IV. Orbital Sciences has drawn heavily on these lifting bodies for their earlier OSP studies. One area that needs changing is the heat shield: the lifting bodies used a system of tiles, similar to the shuttle. Although lifting bodies encounter less heating during re-entry, I still do not have enough faith in the shuttle heat shield to justify using it.
My guess is that the final OSP will be sized to take full advantage of the "heavy" EELVs, and the payload will fall between that of the HL-20 and HL-42. The reduced mission cost will allow more resupply flights to the station to compensate for reduced payload in comparison to the shuttle.
As George Dyson pointed out in his book, Orion may not be technologically or socially acceptable until the 2050-70 time period. Clearly, we will develop NTRs and nuclear-powered plasma rockets before then. But there is hope that Orion will eventually come to fruition, because it is more practical than solar sail or mag sail propulsion.
Each propulsion system will eventually find its niche, rather than one propulsion system replacing the previous one. Chemical rockets are good for transport to earth orbit because of their benign (in the case of hydrogen) environmental effects. NTRs are preferred for lunar transport because it will enable 24-hour transits. Plasma engines, like the tortoise who defeats the hare, cannot sprint to the moon but they allow 90-day transits to Mars. I predict Orion will be the preferred engine for flights to Jupiter, Saturn, and perhaps the outskirts of the solar system. Travel to the stars will be enabled by antimatter or fusion ramjets.
On an unrelated tangent: If any of the "Axis of Evil" nations are still up to their games by 2050 (the odds of Iraq making it that far are the same as a snowball's chance in Hades,) an international Orion mission to Europa will give the nuclear powers an opportunity to disarm multilaterally and deplete their nuclear stockpiles in an effort that benefits all mankind. It's something I hope to see.
Regular visitors to the Enterprise Mission know that, to the contrary, both the current president and the elder President Bush have a fascination with Mars. Bush I called for an expensive and lengthy Space Exploration Initiative that would conclude with humans-on-Mars, Bush II is funding a nuclear rocket program that will enable humans on Mars.
I believe that the Bushes and those of a similar mindset hold a fondness for the space program because they still remember Apollo and they want to re-kindle the pride that the moon landings brought to America. I do not think this current administration will actually call for humans to Mars (even on the occasion of a return to flight for the space shuttle,) but a future administration (Hillary? Bill Frist? Condy Rice?) will probably make the challenge once the Chinese officially commit to a lunar landing.
In order to replace the resupply functions of the shuttle, a vehicle such as MAKS or OSP would need to carry 9,000 kg or so of cargo to the ISS orbit. This is the amount carried in the multi-purpose logistics module. Without this capacity in an alternate access vehicle, the shuttle will continue to be used (perhaps in an unmanned fashion) to resupply the station with experiements. Take a look at the future shuttle flight manifest, now uncertain, and how many flights were devoted to resupply. A significant cargo capacity must be added to OSP to save astronauts' lives and NASA's budget.
Another consideration for OSP is its shelf-life. After all, each Soyuz must be replaced after six months to avoid a systems breakdown. The Air Force and Aerojet have been working on storable, peroxide-based propulsion systems. I don't know how reliable today's level of technology is compared to the 60's vintage Soyuz in terms of long-term system life.
The Soyuz and Progress represent the state of the art from the 1960's. Why, then, are we still using them when we could have a better system (OSP) ? Once OSP is a proven system, there is no reason to continue with these aging vehicles. Ending Soyuz/Progress production might be a blessing for the Russians, too. More funding can be transferred from production to R&D, a field that has stagnated in Russia since the end of the Soviet Union. More R&D is needed before we can proceed with a MAKS / Spacecab, and I feel that the engineers and other "free-agent" scientists of Russia should be employed in this task.
It's true that no nation can PREVENT China from returning to the moon; the question is whether anybody can BEAT them to it.
I, for one, would like to see another moon race, but I don;t think we will. The United States has no morale to boost or fanfare to be gained by returning to the moon. There are plenty of scientific and economic reasons to return, but that will be a private effort and not a NASA effort. Instead, China will have a man on the moon, and probably within the decade.
There is a military aspect to China's Shenzhou manned spacecraft, after all.
Right now, Shenzhou's military role is the benign one of reconnaissance. But the west should still be cautious at this time, because the overtly military nature of Shenzhou might be a harbinger of more aggressive plans for space. This recent development should not come as a surprise to anybody who's been following the Chinese space program.
After Columbia, my immediate reaction was to retire the shuttles and stay grounded until OSP was built. I felt that doing so would also stop us from tossing money at the ISS. But I thought about it a while and begrudgingly said that the shuttle had to be flown again (although I still strongly feel it should be retired when the ISS construction is complete.) The ISS has value, but that value cannot be tapped until it's complete and OSP is built. In order to finish the station, we need the shuttle.
Back in 1986, we made the fateful decision not to fly commercial payloads on the shuttle and not to fly the shuttle from Vandenberg AFB. These two decisions cut back the frequency of shuttle flights and made certain that expendable rockets would always be cheaper than the shuttle. (Of course, government launch of commercial satellites destroys the free market, but it was hoped the shuttle could be privatized.)
I guess the lesson here is not to be rash in our decision making and avoid reactionary decisions that will harm our cause in the future. ISS is an important part of space infrastructure, and a step towards becoming a spacefaring society.
I enjoy using LockMart just to keep things short.
Booster separation would occur at much lower speeds and altitudes than a spacecraft in orbit; think of the speed and altitude of shuttle boosters separation. Buzz Aldrin's Starbooster concept calls for staging between Mach 3 and Mach 6. A heat-sink structure would suffice. My only concern with modifying existing boosters to fly back is that the thin-walled propellant tanks might not be able to survive the bending loads of flight without major modifications.
Steering the thread back to the original topic...
If OSP is launched by an ELV, would it be that hard for LockMart, Boeing, or Arianespace to uprade their launchers with re-usable boosters? I'm certain NASA wouldn't fund the upgrade, but it might be appealing to the companies because it reduces launch costs and increases profit margins.
I think the Atlas V is most suited for this upgrade because its RD-170 engine is derived from the re-usable RD-180. "All" LockMart needs to do is add fins, landing gear pods, a scissor wing, and jets to the Atlas V booster core. Ditto for the Delta IV.
Man-rating and then upgrading the Ariane 5 will be a taller order because I'm leery of the SRBs, and it would be impractical to add wings to an SRB casing. Arianespace has studied various flyback boosters, it's just a matter of implementing the best configuration.
A partly-reusable OSP presents some interesting opportunities. It will be cheaper to fly on a per-mission basis than shuttle, safer due to the all-liquid propulsion, and potentially able to fly polar orbit missions from Vandenberg AFB.