Going back closer to the original topic (since I missed out), the shuttle was originally planned to be replaced about now, by a craft called the Venture Star. That would be a full sized shuttle based off a scaled prototype called the X-33. The Venture Star would have been a single-state-to-orbit design, that carried no external fuel tanks, no external boosters, and used a linear aerospike engine for maximum thrust plume efficientcy during the entire range of atmosphereic densities that the craft would have to opperate in, from sea level to orbit (vacume). It was to be a collection of technological innovations to be a cutting edge spacecraft when opperational. Unfortunatlely, the low-weight graphite fuel tanks being devellopped, would not seal properly and were more brittle than anticipated. The design was changed to accomidate more conventional alluminium fuel tanks, but this had more weight. The design was then altered further to include more fuel (to compensate for the increase in weight), but it required moving the cargo section into an external pod above the main body, increasing drag. That was the last design change I remember before it got canned. This was late in the Clinton administration IIRC. It was basically going quite a bit over-budget, and was taking somewhat longer than planned. Combine all of these factors into a single assessment, and what you have is a craft which is deemed too ambitious to be attainable. It should be said at this point, that a fully reusable single-stage-to-orbit spacecraft such as the proposed Venture Star, is the Holy Grail of earth-to-space spaceflight.
Following the canellation of the X-33 and Venture Star programs, NASA began SLI, or Space Launch Initiative. Basically, it was a program to select a design that was less radical and amitious as the Venture Star, but more efficient than the current Shuttle. It would basically be a fully or semi-reusable two-stage-to-orbit design, with a reduced heavy cargo cappacity. Around this time, Bush had just entered office and internal reviews of NASA revealed considerable cost overruns across the board. Its been said that Clinton was a bit fan of NASA, and got into the habit of delaying the release of some of its financial information until certain points of the year, so that it would end up getting more funding (I can't remember the specifics though). After the review, certain planned segments of the ISS were deleted. A larger propulsion module, a larger crew module, and a specially designed emergency escape vehicle. The latter was designed to fit 7 people, which could only be accommodated by the crew module, so those kinda go hand-in-hand.
During 2002 (IIRC), NASA was once again told to hit the breaks on new shuttle developpment, as the SLI program was haulted for further review. It was replaced with another program (that appears to have no name that I know of) that basically wants to take a commercial heavy booster used for lofting heavy sattalites and attempt to make it safe enough for human use. Then, a much smaller craft called a "Space Plane" would be placed atop it, with perhaps 2/3 to 1/2 the shuttle's crew cappacity and no where near its cargo cappacity. Further "refinements" on this concept basically made it into a high-tech reuseable verson of an Apollo era capsule, with no clear mention of any kind of glide cappability, so it may be back to ocean recoveries. I consider this proposed type of spaceflight, an unacceptable step backwards for NASA.
Then in 2003, Columbia broke up during rentry. While tragic, it forced NASA to take certain actions that crippled it and zapped its momentum. Firstly, it forced a grounding of the remaining shuttles until the cause of the accident was found, understood, and a method to prevent it is devised and implimented. All of these are important, understandable, and completely called for. This also put a stop to ISS construction, and basically left them in a holding pattern, trying to pare back their opperations so that they use the least number of resources until such a time as the shuttles are cleared for flight and construction resumes. This should happen starting next month. This basically took all of NASA's develloppment resources, including that used to devellop a replacement. Both NASA and the Russion space program are in the middle of a race with time, that NASA seems unable or unwilling to win. There is a deal with the Russians about how long whey are expected to provide Soyuz capsules to the station, both to ferry crews and to have one on hand to act as emergency escape vehicle. This runs out in 2008, at which time (under the original agreement) NASA would have its emergency crew return vehicle and replacement shuttle fleet opperational. Now, the shuttles are due for retirement in 2010, but its looking like they won't have anything close to coming on-line until about 2015. The craft that NASA is proposing as its Shuttle replacements, could serve as emergency return vehicles, as the Soyuz craft to today, but what is to fill the gap between 2008 and whenever this space go-cart is to enter service? Right now, NASA is at the mercy of people like Bush, who are
of talk and no action. Basically, Bush's policies are stringing people along until they realize that there is nothing waiting to take over, by which time he'll be either out of office after his 2nd term is up, or at the end of his term where it doesn't matter to him anyway... he's had his fun. [/end anti-Bush rant].
There may be a glimmer of hope, but it all depends on if NASA can get off its assets after RTF (return to flight) for the Shuttle and knucle down to actually selecting, desiging, building, and implimenting the shuttle replacement. They need to be serious about it. It needs to be on the front burner rather than on the back burner set to simmer. The Russians too have indicated they are planning to design a new orbiter, though still rocket and capsule configuration. This likely the result of Chineese success with a more advanced copy-cat design of the Soyuz, prompting an Asian space race or sorts. Unfortinately, it is my opinion that if NASA hasn't even selected a replacement concept by the time the Shuttle is retired, or once again suspends the design program for another review, they should stop kidding themselves, the American people, and their Russian partners that they have any real plans (when I say "real" I mean plans that they fully expect is within their cappabilities to meet in the time alloted), to contine a manned presence in space. It they can't support and maintain the space station when the shuttles are retired, they've got no business being in manned spaceflight and step aside and give the corporations the center stage in space.
As you can guess, the space program (manned, robitic, remote-sensing, and even in terms of physics) is an interest of mine, of which I am quite passionate about. Unfortinately, as a Canadian, I realy don't have any say in how the American goverment and space program conducts its affairs, but with no such program here in Canada, I have to live viariously though NASA and other foreign space programs for my fix. These are my observations and conclusions, which have found their way into this editorial of sorts.
Later!
