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Competition to Build the Space Shuttle's Successor
Neil Halelamien writes "The competition for the prime contract to build the Crew Exploration Vehicle, the successor to the Space Shuttle, is ramping up. Currently, 11 different companies are creating preliminary designs for systems and vehicles which could be useful in implementing NASA's Vision for Space Exploration. By the end of the year, NASA will select two teams to independently develop and build a CEV design. The two teams will launch competing unmanned prototypes in 2008, at which point NASA will award a final winning contract. Aerospace giants Boeing and Northrop Grumman have formed one team. Another "all-star" team, announced a couple of days ago, is headed by Lockheed Martin. A third team in the running is underdog t/Space, a company with a free enterprise approach to space exploration, which includes notable figures from the commercial spaceflight arena, such as Burt Rutan and Gary Hudson. There is concern that a NASA budget boost to help pay for the exploration program could draw some opposition, as most other government programs are anticipating budget cuts."
At a certain point it becomes counter-productive. Just tell me which one to click on to get the article.
After ShuttleOne went up for backing as little as $20 million, is it just me or is NASA throwing around too much money to make this happen? I'd like to see someone else make the new crew vehicle and sell it back to NASA. I guess the other side of the coin is the German's saying Mars by 2009. *shrug* I guess when you have nothing substantial in your space program in the past, you've got nothing to lose with ridiculous goals for the future?
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This does show a fundamental lack of decision making going on in many branches of government leadership. No one wants to put forth a goal and be the leader who didn't make it. So, they don't make a goal so that way they just keep the status quo as long as they can and hope the next guy deals with it. No one or agency wants to look bad so to them it's safer to not do anything at all.
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As I understand it, the reason you can't use anything similar to SpaceShipOne for orbital missions is the weight of the heat shielding. But a capsule like this still has to carry that shielding up to orbit, right?
I don't really see why a spaceplane design is out of the question. The shuttle was hugely complex compared to SpaceShipOne. Couldn't a more modern design of the shuttle still be useful?
For example, they self-orient on reentry, they don't have expensive and heavy control surfaces or landing gear, and from their position on the top of the rocket they can use escape systems like those in the Mercury, Gemini and Apollo programs.
About the only thing they can't do is bring things back down from orbit. But, really, if we want a real future in space the biggest issue is getting things up there.
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The trouble with a spaceplane is its inefficiency. Too much of the energy expended in a Shuttle launch goes to carry the orbiter's main engines, wings and other structure into orbit. If you could leave those off, with a capsule design, you could either save a whole lot of fuel and get a cheaper launch, or use the same amount of fuel and carry a much larger payload.
The idea behind the Shuttle was that the engines were worth keeping, and reusing them could save money. Apollo used to drop its main engines into the sea... But it turns out that there are plenty of factories on Earth capable of producing rocket engines very cheaply, so that economy didn't really work out.
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Actually, it's the "red tape" that makes the smaller contractors certain to lose. You need a small army of people just to manage the blizzard of forms and documents required, let alone do the real work of researching and developing a vehicle. And don't think that NASA's going to let them get away with a bunch of FEAs and flight sims, they're genna have to build and crush a few airframes to get real data. Parent's not entirely wrong, though, a smaller company won't have to share the overhead of managing other divisions and projects as well as pay the salaries of people who have been since wings were made of fabric....
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Spoken like a true Nasa zealot. It took the guys at Scaled composites to show you that they could build a cheap light, ingenious low-earth-orbit vehicle and launch it cheaply from its mother plane.
Sadly, it seems that once again it will take private venture to show us that a highly efficient fully fledged orbital insertion space plane is doable, and at a much cheaper cost than anything Nasa could come up with.
And less complex than the space shuttle??? The space shuttle may be complex but it's just a big rocket propelled glider. Space Ship One utilises a far more complex design princple. It does much much more with far less..
The space plane concept wasn't bad, and it still isnt. One of the main problems with it though was because of constant budget cuts to the program NASA had to keep on taking out certain features of the shuttle which eventually made it what it is now. Some of the original concepts for the spaceshuttle were truly fascinating and much more effecient then the current shuttle.
A capsule has a much smaller reentry profile, accordingly it needs to protect a much smaller area. Hence a much smaller amount of heat shielding is required.
Further, a Capsule falling through atmosphere is kept in the proper orientation through simple newtonian mechanics, it requires no gadgetry to keep it stable, unlike a spaceplane, which is an inherently unstable reentry vehicle.
The capsule is the way to go for cheap and reliable missions.
The reason that the shuttle was inefficient is that it was designed to land without crossing the Soviet Union, not because spaceplanes in general are inefficient. You can make it rather better if you allow for a longer glide path.
"Because Science" is one step from "Because old book". Try "Because of my experiment testing my falsifiable assertion".
After all, while orbital assembly may seem cool, it doesn't seem very cost-effective yet.
It will work a whole hell of a lot better than on earth assembly. To get to lunar orbit, you don't have to worry about earth gravity or anything. You won't need a smooth skin either. It could look like a flying pig and be as ugly as you wanted. You also don't have to worry about the thing staying intact and not getting damaged on the way up.
As for a heavy lifter, That might be what heavy rockets are for. Though I wouldn't mind this: http://nuclearspace.com/a_liberty_ship.htm
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Pathetic, isn't it? Especially considering that space exploration is in the long run the most important and beneficial government program of all (with military being the second).
I hate to be a rtfa poster, but that's exactly what one of the competitors is suggesting. Although they seem to be focusing on teleoperation instead of autonomic tech.
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BTW, the real problem with a space plane is in the aerodynamics. To avoid superheating on reentry (compared to which the space shuttle would be freezing during renetry), all leading surfaces must be big round things. That's why the shuttle looks so un-sexy compared to fighter jets. The wings leading edges cannot be sharp - no known material would survive at 50,000 C. By making the leading edges round, they lower the temperature baring within range of Carbon-Carbon - but that makes the wing have a terrible L/D ratio. In addition, instead of a nice sleek body which could be lightweight, you now have a ponderous blob which must be reinforced at every point.
Taking aerodynamics into consideration, the best design is really like a sphere. The closer you are to a sphere, the better. Apollo took a cone and made a good aproximation of a sphere. The shuttle takes an airplane and makes a bad approximation of a sphere. Lifting body designs look a lot more like a sphere, but soon we probably will know if they are close enough to a sphere.
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First of all, I think that China will probably beat the US in terms of manned space exploration. They will go back to the moon before the US even finishes their new space vehicles. This is sad because China apparently understand economics better than current US leaders do. It might seem that the Apollo program was just a big expensive government program but the truth is that all the expensive science generated far more money that it spent. Science is good for the economy for it provides people with technology that lifts the economy and increases growth in the country. As complicated as going to the Moon and Mars and expensive as it seems might be, it is good for the economy. All the new technologies generate new industries which will further the economic growth. Our leaders in the US have forgotten that by limiting science funding and cancelling things like the particle accelerator in Texas. Second and most important, it is too expensive to think of old ways to get out of this planet. The best and most efficient way is to build the SPACE ELEVATOR. Fund nanotechnologies to get the cable for the elevator built. It is estimated that it would cost $100 a pound at the beginning to lift things into orbit using the elevator and maybe even go down to $1 a pound as more elevators are built. Science fiction but so was landing on the moon before Apollo 11.
When I heard about the DC-X approach to reusable spacecraft reentry and landing, my reaction was "that is so Buck Rogers" meaning that I didn't think that landing on rocket thrust made sense.
But the Soyuz lands tail first on rocket thrust (it has braking rockets for the final ground contact to supplement the parachute), and that has advantages over wings and wheels.
So saying Buck Rogers should mean a solution without wings and wheels.
I disagree. Spaceplanes may be inherently inefficient *per mission* compared to a disposable capsule design, but if maintainance costs were lower, they would easily outshine capsules with disposable rockets.
:)
And maintainance doesn't *need* to be high. If the shuttle had the budget for its initial design plan (a titanium frame, no solid boosters), it never would have had any of the problems that it's had that led to high maintainence costs and its 2% failure rate.
A couple of things about your list:
* A hugely increased heat shield: Not really hugely increased. An optimal shape for reentry is a large, slowly curved surface, and the further from that shape, the larger amount of shielding you need for a given size and density. However, the shuttle manages relatively well given its size and density compared to what an equivalent capsule would be by turning its bottom side into the direction of incoming air.
* Hydraulic motors for flaps: Not necessarily. Hydraulics in space are problematic because of temperature regulation (in the tanks, in the cylinders, in the lines, etc). However, it is possible to use electric actuators to replace them for most, if not all, tasks. Electric actuators are increasingly being used in high force tasks.
However, the key issue is reusability. Reusable capsules have never really come into their own - they tend to have a pretty rough landing. The more payload return you want them to be able to bring back, the rougher it is.
If one can get reusability without high maintainence, in any design, that truly is the holy grail of spacecraft design.
Freeze Ray. Tell your friends.
You asked for craft that works. I delievered. You now accept that they do have craft that works in the past 20 years - lots of them. Right? I rest my case.
Delta IV-heavy is a great craft. Its cost per kilogram is amazing for a rocket built in a first-world nation. The atlas series shouldn't underestimated either. In short, Boeing and Lockheed *have* been doing good work in the past 20 years. You have no right to pretend that they haven't (not that Delta and Atlas have been their only projects - far from it).
Most of these companies' work is military. They've designed more rockets than you can shake a stick at in the past 20 years.
I only mentioned blackbird to show what their materials and engine tech was like decades ago. In 20 years, we'll get declassified as to what sort of materials and engine tech they're using now. These companies do excellent materials engineering work that a small startup couldn't even dream of because they don't have the infrastructure.
How much is "new tech", "invented in the last 20 years"? The vast majority of their core rocket series. The engines used by both the Delta and Atlas rocket series' didn't even exist back then.
Perhaps you mean on a more fundamental level - say, the component level? Mostly new there. The alloys, coatings and other materials used many engine parts didn't even exist back then. Just the other day I was reading about a cheap nozzle throat that Lockheed patented made of a ceramic that has shown almost zero erosion - a critial step in lowering engine maintainence. They just cast it and fit it - a whole lot easier than carbon-carbon.
Just because you see a column of flame belching out of the back of an engine doesn't mean that what's "under the hood" is at all the same. Modern engines far outperform their 1960s counterparts. Modern propellant tanks (which more and more are based on lightweight alloys, such as lithium-aluminum) also far outperform their 1960s counterparts.
I mean, seriously, what do you want - nuclear powered rockets? What will it take for you to call something new?
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