I don’t mean why two shuttles have been lost so far, but a much broader question: Why has the Shuttle failed to provide convenient inexpensive access to low earth orbit, as it was originally intended to do? It seems to me to be a question of the basic hardware: they just can’t seem to get the damn thing to work right.
If the shuttles had performed to the standard first touted for them in the late 1970s, it would have been great. NASA believed that each shuttle could be launched once a month, and that we’d be launching a shuttle a week. Obviously this never happened. Instead of a being a spacegoing 747, the shuttles require a collossal amount of expensive nursemaiding. And after twenty years, NASA has still never worked all the bugs out; if I had a dollar for every time I read the words “crack in the fuelline”, I could spend the weekend in Vegas.
So just why did the Shuttle turn out to be so mechanically unreliable? Bad design? Overreaching program goals? Institutional incompetence? Is NASA irredeemably stuck in the military/aerospace mentality that produces expensive turkeys?
To put it ironically, if we could put a man on the moon, why can’t we put a shuttle into orbit more than five times a year?
Could be a matter of more money being channeled into “war” programs than space programs. I think our war technology has made great strides in the last couple decades, much more so than our space program. It seems that our government is more interested in the technology of killing people than the exploration of new horizons.
Strangely enough, cc, military programs are the genesis of the space program, and the space program as a whole has benefitted greatly from it.
The problem is that space travel is viewed as routine anymore. It is not. It is dangerous. There are great risks, as evidenced by the two shuttles being destroyed. However, just like anything else that’s seen as routine, it gets ignored.
The shuttles are 60s tech built in the late 70s-early 80s. They are hard to maintain and expensive to replace. NASA just tried to squeeze blood from the shuttle stone for too long at it caught up with them. Soon they’ll HAVE to try something else, and they’ll never be able to fund it.
There’s a huge jump between making an experimental program work (i.e., Apollo) and making an industrialized product (the shuttle, as you’re describing it). Think of how long it took cars and airplanes to become as reliable and safe and consistent as they are, and those industries had a whole lot more money put into them than the NASA has ever had.
Monthly or weekly trips in a reusable vehicle is decades in the future at best. Every human endevour requires massive investment, experience, and practical use before it becomes ‘everyday’, and the space program goes at a fraction of the pace of commercial products, in addition to being hugely more complicated.
Until some way to reliably exploit space and its contents for commercial purposes is developed, don’t expect to see space travel become routine.
Personally, I’d like to see a space plane which is lifted to 60,000 feet by a massive jetplane, and then is launched with far smaller rockets.
Obviously, it would require some impressive computational power to get the velocity and trajectory angles correct but I’m pretty sure it could be done rather gracefully these days.
Certainly, you’d be looking at an amazingly lower fuel load at takeoff. If the mother plane was hitting 700mph, you’re already 5% of the way to your required velocity speeds, as well as 25% of the way to your required orbiting height.
I imagine the stresses would be much lower as well because the space plane would effectively be flying into space - as averse to being a projectile sitting on a massive rocket thrust. Admittedly you’d only have 40-50,000 feet of air to fly in before hitting the outer regions of the atmosphere, but still - it would be substantially easier, lighter, and definitely safer.
I agree that the problem mostly lies with the fact that the government is running the space show.
Technologies like the plane and the car were designed and commericalized by the private sector. Governments are more concerned with PR and short term benefits than the big picture. The X Prize was a great idea to once again give the reins to the private sector to get man into space effectively. NASA has had more than enough time and money to figure something out, and they blew it. Its up to the average joes now. And I’ll put my money on them over NASA any day.
They knew it was problematic from the get-go, but Nixon had killed Apollo because it was JFK’s legacy, and Nixon hated JFK. So the poor bastards at NASA were forced into the shuttle program because it was the only way to keep space flight in the US alive at the time.
You can save even more fuel and weight by giving the shuttle ramjets for use between the time it releases from the mother plane to the time it breaks atmosphere.
Ramjets, or scramjets? I understand the University of Queensland has produced a new scramjet rocket engine which has passed the initial prototype stage.
But I always thought a “ramjet” was a type of jet engine design?
A ramjet and a scramjet are very similar in that both have no moving parts like a turbojet and rely on moving foreward at high speeds to squeeze enough air into them to function.
…it is because of three factors:
(1) the SS was designed to do TOO MANY things (launch satellites, shuttle astronauts/cargo to the ISS, and provide its own space laboratory). The need to fulfill these roles made the shuttle:too big and heavy, and prone to structural failure
(2) the design on the shuttle is based on 1970’s technology…and many of the elctronic systems are based on components that are no longer manufactured…NASA has boxed itselfin!
(3) the ENORMOUS cost of building and operating the ISS (including huge cash payments to make the Russians appear to be participating) have drained NASA’s shuttle budgets. As we have seen, this has made maintaining the shuttle fleet very difficult.
Actually, NASA should put the money into building a replacement for the shuttles–they are becomeing unreliable and dangerous, and should be scrapped as soon as a replacement is feasible. All evidenc suggests that this would be the cheapest and best courseof action.
The most basic problem is that you do not need a manned spacecraft, still less one capable of carrying a crew of 7, to launch a satellite. As Cecil himself has pointed out, there is not much point in manned spaceflight at all.
Which was, as mentioned earlier in the thread, a make-the-sale-at-any-cost pitch in order to give NASA’s Manned Spaceflight program some reason to live after the Moon Race, in the eyes of a Congress and public opinion that were cheap about money AND demanding about America having to do something “big” and “high tech” . Problem is, these promises were being made about a system that did not exist except as designs. Vaporware, so to speak.
It did not help that due to a combination of budgetary limits AND internecine political games in NASA and the military, the de-facto policy of the USA was that there be one and only one manned program/vessel class flying at a time, in a strict order of commitment, and each program/ship would just plain be decomissioned as-soon-as or even before the next one flew. The Skylab and ASTP missions in the 70s were flown with surplus Apollo gear that had been already in the production line when it was decided to wrap up the Moon project, so when we ran out of it, it was wait for the Shuttle, however long it took and whatever problems there were.
The legacy of these mentalities hinders replacement of the STS – on one side, the fear that if we EVER finally commit to a working replacement (or rather a set of working replacements: trying to be-all-to-all means you end up with an inefficient system), the suits will kill the existing program w/o waiting to see how long it takes to work out the bugs on the new stuff; which impinges on the other side, how we “must” have something several orders of magnitude superior to anything around and “good enough” is not good enough (see also: Osprey aircraft vs. just buying the Marines a good current-model medium helo), so it’ll take years of fidgeting with every last specification; and of course, the political millstone: that whatever it is HAS GOT to finally make it “routine” and “safe”, and “cheap” to get to space NOW (“Dagnabbit it’s 2003, if we can’t have flying cars and android maids we can at least have routine spaceflight!!” )
Like hansel said, you cannot decree that a particular technology WILL pass from the “experimental” to the “specialty” to the “industrial commodity” stage just because you say so. And the perfect is the enemy of the good enough. The people doing the appropriations should know that.
I can’t remember where I read it, but I recall reading a source that said the shuttle program was supposed to only run for 10-15 years, at most, at which point a safer and more modern alternative was to take over. And since that alternative has not yet arrived, we have seriously extended the use of the shuttles to the point where they’re literally being held together with duct tape and twine.
Part of the problem was that the Shuttles weren’t supposed to last this long, but they were supposed to go through many more airframe cycles. I seem to recall that each shuttle was supposed to fly something like 100 times, over the space of about 10 years. But Columbia was 20 years old, but had only flown 28 missions.
That put the vehicle in uncharted waters from an engineering standpoint. Flying very infrequently is not good for a vehicle - seals dry out, parts corrode, etc. So the maintenance cost per flight goes higher, and more unknowns are entered into the situation.
Perhaps the most venerable airframe ever built is the Boeing 707 airframe - which first flew in 1957 and is still used to this day as the work horse of the USA’s in flight refueling tankers. (Not to mention the B-52 as well obviously…) But the 707 airframe is something special. It’s predicted that it’s such a well made airframe that it’ll continue to act as an inflight air tanker well until 2050 - which is a really impressive life for an airframe.
However, the research also shows that the only airframes which will achieve this are the ones which fly regularly - every two or 3 days. It seems that sitting idle is the worst thing possible for an airframe - according to what I’ve read. They’re simply impossible to ever “truly claw back from the path of ruin” if you know what I mean.
QUOTE]*Originally posted by Boo Boo Foo *
**Personally, I’d like to see a space plane which is lifted to 60,000 feet by a massive jetplane, and then is launched with far smaller rockets.
Obviously, it would require some impressive computational power to get the velocity and trajectory angles correct but I’m pretty sure it could be done rather gracefully these days.
Certainly, you’d be looking at an amazingly lower fuel load at takeoff. If the mother plane was hitting 700mph, you’re already 5% of the way to your required velocity speeds, as well as 25% of the way to your required orbiting height.
I imagine the stresses would be much lower as well because the space plane would effectively be flying into space - as averse to being a projectile sitting on a massive rocket thrust. Admittedly you’d only have 40-50,000 feet of air to fly in before hitting the outer regions of the atmosphere, but still - it would be substantially easier, lighter, and definitely safer.
Probably a shitload cheaper too. **
[/QUOTE]
I’ve made the same argument with engineers connected to next generation orbitors. It all comes down to velocity. To stay in orbit you have to be traveling at least 17,000 mph. A dual vehicle launch would require a carrier vehicle moving much faster than 700 mph to be of any use. This idea has been kicked around since the dawn of time but it isn’t going to happen on the back of a 747.
IMO there isn’t anything “wrong” with the shuttle. It was (is) on the cutting edge of technology in a field literally without equal. If you look at the shuttle from a cost/use standpoint you are stuck comparing it to older/proven technologies. However, if you look at it as an evolutionary step to the next frontier of orbital/space travel it is both necessary and successful.
There ARE factors that can be addressed that affect the current program. Money was cut in the 90’s which in turn caused an exodus of senior engineers. The most recent accident can also be partially attributed to changes made in insulation (for environmental reasons).
**Under pressure during the 1990s to cut costs, NASA reduced its work force by nearly a third, from 25,000 to about 17,000. Many of those who left were veterans taking early retirement. The agency recently began adding staff amid concerns that the cuts went too deep.
“It’s been a long time,” said David J. Norton, who co-authored the report with James L. Rand while they were at Texas A & M. “There have been a lot of changes at NASA, so I’m not sure if anybody would have remembered.”
It’s not clear whether the assessments made in the 1979 study would be applicable today, because NASA switched to a new type of foam insulation for the tank in 1997.
The insulation protects the fuel tank from heating up during launch. The newer insulation, which was developed for environmental reasons, created more problems. A 2001 NASA report said the foam actually caused “greater damage” to the shuttles than in previous flights.**
There are some interesting programs in the works that could provide real alternatives to the current system. NASA is working on a combination ramjet/scramjet engine. I would not be surprised if there is a 2 stage system that is refueled after takeoff to increase payload, utilizes conventional fuel to a high mach number, and is then boosted into orbit with solid rockets.
I would end with an opinion that (in my life time) anything traveling 17,000 mph is subjected to stresses that would preclude it from being used for commercial travel.
I agree that 17,000 mph is the break even point for orbital elevation. My theory is that the the speed of a mother plane is not so important as compared to the height that it’s at. A 60,000 feet staging point is demonstrably on the way to orbiting height. Obviously, the speed takeup would need to be achieved after leaving the launch plane, but there is no rule in physics which says that such a velocity buildup has to take place in a vertical trajectory. It can equally be achieve at a 45 degree angle, or even a 30 degree angle to horizontal. The difference is that the computational start point is a moving start point - as compared to the stationary start point which a ground based launch pad provides.
Still, it has to be said that the majority of fuel in a typical Space Shuttle launch is expended within the first 60,000 feet - which means that the idea is certainly worth fleshing out in my opinion.
The challenge would be the computational power needed to accurately get your trajectory vectors right… most people don’t understand that orbital flight is effectively a perfectly balanced state of falling… too much upward vector and out in to space you go… too little vertical vector and you never achieve orbit and zero gravity.
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