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If the Air Force wants "space fighters" so badly, pirating the White Knight is not the way to do it.
The airplane has the right layout for dropping daughter-ships, but it is far to small for anything that would orbit the earth with a useful payload.
By contrast, Boeing was working on a system called "Air Launch" to put the X-37 into orbit. It consisted of an entire Athena rocket with Pegasus-style tail and wings, launched from the back of a 747. And the X-37 is not very big to begin with; it's essentially a recoverable micro-sat like the other ones the Air Force has on the drawing boards and in the experimental phase.
Sorry, but I think that space fighters will remain solely in the realm of the George Lucas profit machine for many decades to come.
Why not a modular vehicle that can be configured for crew or cargo but not both at the same time?
Boeing's Space Launch Inititive vehicle had two identical flyback boosters, mounted in parallel, with either a small, X-37-ish spaceplane or a cargo pod on top of the stack. In a similar design from Northrop-Grumman, the lifting-body spaceplane sat axially atop one of the boosters (ensuring for easy emergency escape.)
The lesson we can take from Delta IV and Atlas V is that vehicles should be designed from the start as modular systems that can adapt to different missions.
In reference to NASA's problems with Mars Direct:
I don't think NASA is concerned that Martian resource utilization won't work. Instead, there is a concensus that you could land a lighter ascent vehicle (instead of Zubrin's ERV) on the Martian surface, and still get the vast majority of your delta-V for earth return by producing propellant for the flight from Mars' s surface to Mars orbit. The overall result is less spacecraft and fuel mass being sent to Mars.
NASA has other problems with Mars Direct. They want a crew of six, Zubrin thinks you can get away with a crew of four. Rocky Persaud, president of Canada's Mars Society, did some time at a Mars analogue station and remarked that even six might be too few for a Mars mission.
I've also spoken with some people who did the ERV design contest (Kepler Prize) and they feel that Mars Direct, in its purest form, is unrealistic and unworkable. Granted, I saw some significant problems in their proposal, but I feel that these would not have affected their overall conclusion.
Personally, I prefer the Stanley Borowski (et. al) version of NASA's DRM. It retains Zubrin's ideas like artificial gravity and Martian resource utilization (at least for the flight to Mars orbit,) introduces nuclear-thermal propulsion, and incorporates some reusability. Check it out and tell me what you think.
http://www.spaceref.com/news/viewpr.htm … 5057]Could an antarctic telescope outdo Hubble?
Maybe this is a viable alternative to another Hubble servicing mission. Interestingly, much of the structure will be built from packed ice.
My feeling is that Hubble will still have advantages over the antarctic telescope (should it be built,) but the science-cost ratio of this icy observatory is potentially higher.
I'm very excited to see that NASA is actually teaming with private industry rather than poo-pooing their accomplishments like in the Dan Goldin days.
The X-37 should not be viewed as Rutan's attempt at an orbital spaceplane. It will probably never make a powered flight, just glide flights from White Knight.
There have been rumors that Burt Rutan wants to make an orbital, one-passenger version of SSO. I am a bit skeptical of this but I also feel that if anybody could do it, it would be Burt Rutan.
In the near term, I expect him to build Space Ship Two, which would fly higher and give passengers more space to float around in. It would probably need a pure liquid-fuel engine instead of a hybrid, but would otherwise be similar to SSO.
I agree with Rob S. He-3 mining is a LONG way off. We need to get a lot better at hot fusion before we can seriously consider He-3 mining.
If we want the moon to give us a short-term power source, solar power would be a better bet. One objective of human lunar return could be the construction of solar panels from lunar regolith and beaming microwaves back to earth. With no atmosphere to scatter solar rays and abundant constrution materials, the moon is an ideal place for solar power.
GCNRevenger, I totally agree. We should be more concerned with preventing loss of crew as opposed to loss of vehicle. Man-rating it would consist of extra instrumentation that would trigger the escape tower if a failure was detected in one of the rocket stages, such as loss of tank pressure, engine overheating, or loss of thrust.
In response to BWhite:
The fuel fraction of SRBs had been enhanced in the past with the all-black, filament-wound casings developed for Vandenberg launches. After Challenger, the casings were re-examined and discovered to not meet specifictions. However if the SRB is going to be expendable, these casings might meet that lower standard.
The purpose of the 5-segment SRB for the standard shuttle is to increase payload delivered to higher orbits and ISS. The limiting factor is how much payload the shuttle could return in an abort scenario. The new boosters will not allow an increase in max payload, just an increase in how far it can go. Their primary benefit is what they can do to enhance a future shuttle-derived rocket.
I did some checking on astronautix.com and got some good statistics for the Delta II (The Delta 7000 series.) It has had one total failure and one partial failure in 96 launches. Both instances of failure had to do with the solid rocket motors.
I'm starting to lean aginst SRMs for a Delta IV upgrade, but I'm also thinking about the reliable Delta II core for new launchers. Maybe a Delta II cluster (like the MDD Barbarian) or an RLV based on the Delta II first stage tankage and engine could produce useful boosters.
If Delta IV can get some launches under its belt, we might be able to make a better call on whether we want an evolutionary upgrade of the EELV's or something new and revolutionary. Right now, the facts support an evolutionary upgrade.
Honestly, I think some of the safety concerns have been mitigated over the years. Having multiple, independent CBCs on the first stage does multiply your failure rate, but then again the failure rate on modern ELV's has been quite good. It's around 1% for Delta II and 0% for the now-retired Atlas II. Part of these vehicles' heritage is that they evolved from rockets with much higher failure rates: the Thor/Delta and Atlas ICBM/Atlas-Agena/Atlas-Centaur series.
The more we build and fly, the more we learn. Delta IV and Atlas V haven't been flown enough to establish their reliability as ELV's, but if they are on par with their predecessors, we will be well served.
SpaceShipOne uses a hybrid engine, which has superior safety systems to a pure solid (at the expense of performance.) If the engine fails, you cut off the oxidizer or dump it completely.
Thrust termination was considered after the original flights of STS. It would involve blowing off the nose of the SRB so equal amounts of exhaust would exit the forward and aft ends of the booster. It doesn't take a lot of imagination to see the problems with this scheme.
http://www.thespacereview.com]The Space Review has a new piece about a scheme to use a shuttle SRB to boost the CEV. Astronaut Scott Horowitz seems enthusiastic about the idea. However, I have a few misgivings. It is a solid rocket booster, and while such rockets are pretty reliable compared to their liquid equivalents, they can't be shut down during a launch failure. Also, it would take plenty of time and money to build this new SRB-based booster. The Delta IV and Atlas V have already been developed and tested. I tend to think that man-rating these boosters will be less difficult than some people think, and the same process will have to be applied to the new booster anyway.
That being said, there are some interesting things to be found in the article. Knowing that Rocketdyne still has a dozen J-2's and could produce more is very encouraging, as we will need these rockets somewhere down the line in the race to the moon.
Back when the shuttle was first designed, there were plenty of innovative designs that were rejected then but still are valid now. These include:
1) The Chrysler SERV, a VTOL rocket that used lift-jets for landing. Lift-jets save on the weight needed oxidizer. The design also used a conventional heat shield rather than the unproven "plug nozzle" heat shields of the period.
2) The Lockheed LS-200 / Starclipper, a lifting body that was assisted by putting some of the propellant in two external fuel tanks that formed a v-shaped collar around the nose. The vehcile was designed by RLV proponent Max Hunter, and the only expendable component would be the simple fuel tanks.
3) Max Faget's DC-3, a TSTO space plane. The vehicle's payload was smaller than the eventual STS, which enabled its feasibility. Yet the concept dictated the development of two different vehicles, an expensive impediment to building the system. Also, Faget's stub-winge orbiter had a tendency to spin at hypersonic velocities, meaning that it would need some serious re-design.
My knock against TSTO is that it requires development of two separate vehicles in most schemes. I prefer concepts like MUSTARD and Boeing's SLI study that use two or three similar boosters with propellant cross-feed. That way you can develop one vehicle but still schieve two or three-stage orbital designs.
Ther are probably appropriate uses for all three configurations: SSTO VTOL, stage-and-a-half VTOHL, and bimese TSTO VTOHL. There is also a case to be made for a Kistler-type TSTO with parachute recovery of both stages. If there was greater privatization of the launch vehicle sector, perhaps there would be competition to design a Delta II or Pegasus replacement that would result in many different, competing vehicles being built and competing on a per-launch basis.
There will always be people who detract from manned spaceflight and push robots as an alternative. Some of these folks remain downright ignorant of what space exploration entails (like Elanor Clift of Newsweek) while others are respectable scientists like James van Allen and Jeffrey Bell.
Robots have their advantages, but human scientists and explorers are occasionally needed. Humans have the gift intuition and flexibility, unlike the robots which are tailored to do particular missions. The robots in the past have also been fairly limited in scope. That's why we gained so much more knowledge about the moon from Apollo than we did from all of the previous unmanned missions combined.
If life is definitively found on Mars, it will be found by a human examining soil samples in a Martian lab rather than by a robot examining soil a few grams at a time, being monitored by scientists after a 20 min. time delay.
People should always use the right tools for the job. As advocates of manned spaceflight, we need to convince the world that there are some missions for which humans are necessary.
It's become a New Mars ritual: Jeffrey Bell posts a new op-ed on Space Daily, and now we post like mad to weigh in.
The topic of the week is Genesis and "The Andromeda Strain." I take my usual position in that I think Bell makes good points but goes too far in his position.
If Mars Sample Return takes place in the next fifteen years, it may be better to retrieve the capsule from earth orbit using a shuttle or CEV. Or maybe the MSR capsule will need to be made beefier, to incorporate braking rockets and a crushable backside (the first fix would improve reliability and eliminate the need for a helicopter, but not save us from the problem that hurt Genesis.)
Jeffrey Bell mocks poor Bob Zubrin over the perceived risks of Martian life. The logical view is that because nobody has ever observed Martian life, nobody can say whether it is dangerous. The best approach is obviously to take it one step at a time, to study Mars, search for life, and characterize life should it be found.
Perhaps the recent methane and ammonia measurements may lead scientists towards existing Martian life. That should hopefully catalyze the scientific exploration of Mars. It would be a mistake to rule out humans-to-Mars in the event that Mars has life.
I've looked over some of Boeing's proposals, and some look promising while others seem impractical. Eventually the cost analyses will show which ones are viable.
Al-Li tanks are a no-brainer, but other mods aren't as obvious. How much will modifications to the RS-68 engines require? Densified propellants will require regenerative cooling on the engines. Cross-feeding would improve the vehicle's engine-out survivability, but it will also add to the cost of the new vehicle.
New facilities for the 5 and 7 CBC variants defeat the purpose of advanced Delta IV derivatives. If Boeing wants to build new pads, they should go with a new design of a wider diameter and different length, while still using Delta engines and construction methods.
I found this interesting link during my web surfing about Boeing's http://www.boeing.com/defense-space/spa … pdf]future plans for the Delta IV.
The debate of "Shuttle-derived versus clean-sheet booster" comes up again. If Boeing is willing to pump in the development money, it's certainly a possibility. I'm already intrigued by the possibilities.
If a heavy-lifter can be assembled from parts of smaller rockets already in production, it can be economically justified (whereas Shuttle-C et al will not likely see much profit.) Boeing could do a modest upgrade (uprated engines, more SRM's. lighter fuel tanks) or they could do something drastic and match the Saturn V.
My gut says that we do not need to match the Saturn, and that 80 tonnes to LEO will be sufficient.
I'd like to hear your thoughts on an upgraded Delta. I have some ideas of my own that I will elaborate on later. For starters, does anybody see problems with demolishing now-retired Pad 36A in the near future to build a pad for Delta IV Super Heavy?
It's always good to have some competition to SpaceShipOne, such as DaVinci and the other teams that will be attempting a launch soon. Yet the downside is that none of these teams can really compete with Rutan, even though one may beat him into space.
For starters, SpaceShipOne went through a cautious and exhaustive flight test program. It has also been designed for quick turnarounds and almost-assured reentry.
The other competitors have mostly gone for simpler, vertical takeoff and landing approaches. This is a way of achieving first flight quickly with assured reentry, and there is nothing really wrong with it. However, Rutan's air-drop approach is arguably better for the purposes of a tourist vehicle. It keeps the tourists off their backs while they are waiting to launch, gets them to launch altitude with a piloted, powered aircraft, and returns them to earth gently on a runway.
Most distressingly, the DaVinci team wants to compete for the X-Prize on its first flight in what looks like a tight race with Rutan. If they weren't playing catch-up, they might have time to launch a few missions to the upper amosphere before attempting the X-Prize.
I am afraid of what will happen if somebody gets killed in the initial suborbital flights, as the US or Canadian governments may decide to regulate the industry into the grave. Rutan's approach has minimized this possibility by slowly pushing the envelope and fixing the bugs (and even then they nearly met disaster.) The DaVinci team had better get it correct the first flight.
In short, I like the idea of sub-orbital competition, but I believe that the other teams should not rush their programs to beat SpaceShipOne. Rather, they should slow down precisely because of the lessons we learned from SpaceShipOne. Even if Rutan wins the fairly meager $10 million prize, the real money is to come when the sub-orbital companies begin offering passenger flights. The Rutan competitiors should not lose sight of the long-term goal.
The X-Prize is not a break-even proposition. The estimated cost of building a vehicle and winning the prize is around $20 million. The reward for winning the X-Prize, however, is the space tourism market, which will be opened once the prize is in hand. As lucrative as that is, it doesn't apply to the Mars Society. Although I'm sure that a large number of MS members support space tourism, space tourism doesn't do much for bringing us closer to Mars.
You actually think China has a valid argument for "challenging American hegemony" over the moon? When a country has abandoned a place like the moon, it has lost all control over it. After all, territory must be defended if it can be held onto.
I support Chinese lunar exploration, I'm just saying that America should not back down from the moon after expending so much effort getting there in the first place. We must go back to the moon, for the sake of our scientific and intellectual growth as a society.
I do believe that the Chinese space program is driven by nationalistic zeal, much as the American and Soviet space programs used to. It remains to be seen whether they will continue with missions to the moon after finally reaching it.
The challenge to the United States, obviously, is to prevent Chinese hegemony over the moon. From a standpoint of national pride, it is disappointing to know that we would reach the moon first but then abandon it so our Chinese "friends" could monopolize it.
Promtheus gives us hope that we, too, can return to the moon in the same period that the Chinese will go. Dr. Stan Borowski and his team at NASA-Glenn have investigated nuclear thermal rockets and lunar applications for them. An NTR shuttle would allow humans to fly to the moon within a day. The team developed this "LANTR" concept to show how an earth-moon infrastructure could be established, using NTR shuttles and lunar oxygen.
Someday America will be forced to go back to the moon. Hopefully, that day will be sooner, not later, and Prometheus will help us to get there.
I don't think you will see a formal announcement from the president on the issue. This is more of O'Keefe's "sphere of influence." And I certainly feel that President Bush does not like to "change subjects"--he repeats his same arguemnts until he achieves results. He's never spoken about space before, and I doubt he will bring it up before Iraq and the economy are fixed.
Yay breeders!
I've heard that our proven Uranium resources will only last for fifty to eighty years if we continue to use these thermal reactors. The solution lies in the form of fast reactors and fuel reprocessing.
There is important, ongoing research at the national laboratories regarding fuel reprocessing to extract actinides from the waste. This pyroprocessing system has dstinct advantages over the current reprocessing metods used by countries like France.
This increase in fuel efficiency should stretch our uranium reserves to about a thousand years. It is my hope that the waste from Yucca Mountain will be eventually reprocessed, as well as weapons-grade material from decommissioned nuclear weapons. The more effort you put into terrestrial nuclear power, the greater gains you make with space nuclear power.
Although I have a nearly-nonexistant background in nuclear engineering, I would suppose that it's possible to build a "clean" NTR for ground launch.
In the same way that the heated, irradiated water from the reactor does not drive the turbine in a pressurized water reactor, I assume you could build an NTR according to the same principle. Hydrogen would be pumped through a heat exchanger loop that absorbs heat from the reactor's working fluid. I believe that Max Hunter's "RITA" SSTO used this approach.
Actually, in response to Rob S, the White House opposed the Pluto-Kuiper express because it didn't use advanced propulsion. Sean O" Keefe had gone on the record saying that the Pluto mission should be delayed until an RTG-powered ion thruster was ready. Such an engine would enable a Pluto Orbiter. The current mission will use chemical propulsion (although an RTG will provide power) and make a simple flyby of Pluto.
The nuclear propulsion team at NASA-Glenn Research Center has examined LOX-augmentation of nuclear-thermal rockets to boost their thrust. LOX would be injected into an afterburner section of the nozzle, increasing the thrust by interacting with the heated hydrogen. It's been called a "reverse scramjet" because the cobustion would take place in a supersonic flow.