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A Brief History of the Space Station
HyperbolicParabaloid writes "A story about the history of the International Space Station, and its utility or non-utility for space exploration. One interesting insight: after the Challenger explosion it became obvious that we would never refuel a rocket with volatile fuel at a space station because the threat to the station would be so great. And did you know that to accomodate the Russians, the space station is in an orbit that makes it almost useless as a jumping off point to anywhere?"
From Glory to Sideshow: The Space Station's Story
By WILLIAM J. BROAD
Published: February 3, 2004
In 1989, when the first President George Bush announced his plan to send American astronauts back to the Moon and on to Mars, he called the proposed space station "our critical next step in all our space endeavors." It would be a base in the weightlessness of space where big rockets would be assembled and blast off on voyages of exploration: "a new bridge between the worlds."
Now, with the outpost hurtling through space 240 miles above Earth and with 16 nations struggling to complete the most challenging engineering project of all time, the station has suddenly become a $100 billion dead end.
The current President Bush made no mention of it as a steppingstone in his speech on Jan. 14 reviving the call for missions to the Moon and Mars. Instead, he spoke of it as a site of biomedical research and an "obligation" that the United States had to help finish.
Mr. Bush gave no clear indication how, or whether, the United States planned to use the station after its prospective completion in 2010. With NASA focusing its efforts and its budget on the Moon and Mars, the station's prospects are uncertain.
"I'm worried that they're going to cut off the space shuttle before we have another vehicle that can fly," said Senator Bill Nelson, a Florida Democrat who is the only current member of Congress to have flown in space. "And that will drastically reduce space station use."
What happened? How did the station go from star to sideshow? Experts cite a litany of factors: cost overruns, design changes, new perceptions of technical risk after the shuttle disasters and shifting national priorities. For instance, orbital changes to accommodate Russia after the cold war made it harder to use the station as a launching pad.
The tale has no real bad guys, the experts say, but many false promises.
"It was always a steppingstone to the stars," said Dr. Howard E. McCurdy, a space historian at American University. "It was sold as all things to all people."
Dr. Alex Roland, a former NASA historian now at Duke University, said a moral of the story was that Congress and the public needed to work harder to hold the space agency accountable for its dreams.
"They keep getting trapped in their own rhetoric," he said. "They're willing victims of it. But as public policy it's a disaster because it feeds unrealistic expectations."
At the start of the space age, visionaries invariably saw outposts in earth orbit as jumping-off points. Dr. Wernher von Braun, in a famous 1952 article, told of a huge inhabited wheel. "From this platform," he said, "a trip to the Moon itself will be just a step."
In 1968, Stanley Kubrick's movie "2001: A Space Odyssey" featured a giant outpost in Earth orbit that was a way station to the Moon and Jupiter.
Finally, after decades of fantasies, President Ronald Reagan proposed in 1984 that the United States actually build a space station. It too was envisioned as a hub for colonies on the Moon and Mars. For Mr. Reagan, the station also represented a way to challenge the Soviet Union. In the cold war, Moscow made human outposts a hallmark of its space activities.
But Congress did not vote construction money to pay for either Mr. Reagan's vision or that of the first President Bush. Not until 1993 did a new a new vision for space take shape, this one emphasizing harmony over rivalry. That September, President Bill Clinton announced that Russia had joined the station effort as a full partner. Its giant rockets were seen as a boon for the project and a good backup if the shuttles should again fail catastrophically, as the Challenger did in 1986.
"One world, one station," said Daniel S. Goldin, NASA's administrator at the time.
There was just one problem. For the Russian rockets to reach the grand unified station, it would need a different orbit.
Shuttles flying out of Florida usually go into an or
Organic free-range music... yum!
Here.
I am one of many. My idea is not unique, nor do I expect my voice alone to sway you. I speak in a chorus of opinion.
The station is in an inclined orbit of 50 degrees, because Baikonur, the Russians launch site, lies at about that latitude. It takes a lot more energy to launch a shuttle to that inclination than its normal 30 degrees. There are also fewer launch opportunities. One benefit of having the station at a high inclination is for earth observation. It flies over a lot of ground. But it is an expensive way to take pictures isn't it? The station was a bad idea pursued to the bitter end. Credit George W. Bush for changing NASA's focus on it.
an ill wind that blows no good
One interesting insight: after the Challenger explosion it became obvious that we would never refuel a rocket with volatile fuel at a space station because the threat to the station would be so great.
Presumably, refueling tanks would be tacked on the ISS, not kept inside the pressurized sections for storage. Therefore, unless the tank violently busts apart (unlikely, a steady leak is far more probable, even in case of a collision), there's no danger of the fuel leaking out and roasting the space station to oblivion. More likely, there'd be a leak, frozen fuel would be dumped in space, and the tank would empty more or less fast, possibly forcing the controllers to stop the ISS from spinning and/or reorient it. There is no such thing as volatile fuel in an atmosphere-less environment.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
And did you know that to accomodate the Russians, the space station is in an orbit that makes it almost useless as a jumping off point to anywhere?
While this may be true, the ISS was already to be in a horribly useless orbit to begin with, Russians or not.
Because of a weakness in the shuttle and the immense weight of the station, the station is in a perpetually decaying orbit. That is, to say that the shuttle, each time it docks with the station, has to fire its boosters while docked in order to push it back to a higher orbit. If the shuttle doesn't go back to the statio within the next few years, the ISS will go the way of SkyLab. (The Progress and Soyez ships do not have enough power to push the ISS high enough.)
Why put the station in such a poor, low orbit? Because the shuttle can't fly that high.
A recipe for disaster if I ever heard one.
"Why put the station in such a poor, low orbit? Because the shuttle can't fly that high."
It's not in a low orbit because of the shuttle, it's in a low orbit because it's manned and therefore cannot go higher without being either in or beyond the Van Allen belts: in the belts you'll kill the crew real fast, outside the belts you'll kill the crew the next time there's a solar eruption that emits a lot of radiation. No manned station is going to be much higher than ISS without a lot of radiation shielding.
"And did you know that to accomodate the Russians, the space station is in an orbit that makes it almost useless as a jumping off point to anywhere?"
I'm sure the astronauts currently living on the station are quite thankful for this as the United States does not have another vehicle and they would all be dead if Russia could not reach them now that the shuttle has been grounded for a year. Should China and/or Japan enter into this endeavor from a launch vehicle point of view, being accessible is hardly a detriment to the utility of the station.
Clearly, the utility of being able to reach the station from Asia for existing missions far outweighs the utility of using the station as a departure point for missions that have yet to be defined. Besides, the station design is that of a scientific laboratory, not of an orbital drydock. Having already ruled out refueling, can you imagine constructing a transport vehicle in the middle of that tangle of trusses and solar panels? If both construction and refueling are out of the picture, what's left? A snack bar? Seriously, that thing isn't even designed to handle an espresso machine.
You sure they're a bunch of rocket scientists with cold, hard facts and plenty of good data and insight, and not just complaining because of a political agenda - ie; it's election time and they're running a slurry of "look how the conservatives are wasting our money for broken stuff when they could be giving prescriptions to old people" articles?
Who cares if its a jumping off point for anywhere? It was never intended to be, AFAIK. It was never meant to be an interplanetary gas station. It's an orbiting research laboratory, plain and simple.
It's value to the scientific community is tremendous, it allows a ton of research into weightlessness, living in space, etc. That's its purpose.
I don't need no instructions to know how to rock!!!!
Terminal velocity is the maximum speed you'd reach if you fell off the ladder at the top. Gravity would be pulling you down, air friction would be pushing you up, eventually they balance and you reach a maximum speed. In a vaccuum you'd keep accellerating till you hit the ground.
You're talking about escape velocity.
Yes, you would, that's the idea of the space elevator that's brought up from time to time. But you'd be expending energy constantly on your way up.
Think of it more that you fire a bullet straight up, how fast would it have to be going to leave earths gravitational well? You expend your energy all at once - like the big engine on a rocket. That's escape velocity.
I don't need no instructions to know how to rock!!!!
An ejection from the ISS's orbit would get you as far from Earth as an ejection of the same energy from lower inclinations. The question is, once you look at the solar orbit you achieve, how much energy got spent on actual orbital change as opposed to inclination change (relative to the ecliptic).
Even the craziest orbit will offer two opportunities per year for a clean ejection, but that is certainly very restrictive for use as a "stepping stone" to anywhere.
who are those slashdot people? they swept over like Mongol-Tartars.
Terminal velocity is the fastest speed at which you can fall. Air resistance prevents you from going any faster under gravity alone, so the exact velocity depends on your shape and size. Yes, you do mean escape velocity. Escape velocity is the speed necessary to completely escape Earth's gravity, NOT just to reach orbit. If you reached escape velocity, you would fly off away from the earth entirely, not end up in orbit. As to the ladder problem, the speed you get is the speed of the ladder being whipped around the earth like a rock on a string. The higher you go, the faster the end of the ladder will whip around. If you ran the ladder all the way up to geosynchronous orbit (the height where an object orbits at the same speed as earth's rotation) you could just hop off and be in that orbit. If you got off lower or higher, you wouldn't be going at the right speed to maintain that orbit and would fall to earth or rise to a higher orbit. Incidentally, another problem is the strength of the ladder. Each separate bit is at a separate height, so each is going too slow or too fast for the orbit at that height and so wants to lead or lag behind the rest of the ladder. The stresses are too much for any ordinary material - that's why people who discuss space elevators talk about using carbon nanotube materials!
1) Once the U.S. congress cut the funding for the habitaion module, the ISS officially became an orbiting pork barrel. It takes 2.5 people to maintain the station, and with 3 aboard that's .5 peopple for science. The hab module would have accomodated 7 scientists.
2) On fuel-in-space and There is no such thing as volatile fuel in an atmosphere-less environment.
Let's keep looking at this: Volatility doesn't mean simply explosive, and it is true that fuel requires an oxidizer in space, however, here are some problems:
a) Fuel is "sticky". Not sticky like glue, but when it comes into contact with things in microgravity, it stays there.
b) Fuel is caustic and corrosive. There are so many things that we do not want fuel sticking to, such as gaskets, joints of mechanisms, windows, experiments, instruments, and space suits because
c) Much of the fuel for satellites and such are not simply liquid oxigen and nitrogen, but stuff like Hydrazine, which has too many immediate dangers to list. In short, a small amount coming in through an air lock after an EVA could asphyxiate everyone on the station, be ignited by static, etc.
d) In case all that wasn't enough - just how can we approach the ISS if there is a cloud of fuel around it*? We can't fire any thrusters (with their own oxidizers) into a cloud like that.
Ok I'll zip it now.
kulakovich
* Yes, I know, there is already a cloud of bits and pieces and ice and etc. But that is nothing compared to a fuel leak.
Terminal velocity is the maximum velocity you will reach if you start from stationary and are accellerated by gravity through the atmosphere. Obviously it's a function of mass, aerodynamics, atmospheric pressure and strength of gravity.
On earth we can assume gravity is fairly constant and pressure is dependent on your altitude. If the pressure is zero (because you're in space) then mass and aerodynamics don't count because everything accellerates at the same rate, but in the atmosphere, something with a lot of mass and good aerodynamics (i.e. low drag) will have a higher terminal velocity than something with very little mass and poor aerodynamics (i.e. high drag). Think of the difference between dropping a feather and a rock.
http://blog.nexusuk.org
I dont think the ISS orbit was chosen to accomodate Russians.
It takes the least amount of fuel to put something in orbit if said orbit at the the same angle as lattitude of the place you are launching from.
51.6 degrees (ISS orbit) is lattitude of Baikonur, Russian space port. The space station was started by launching large building blocks by Russian D1 boosters. I do not think there is an equivalent to those in US. So the choice of orbit was natural to maximize the available technology.
-T
What? Fuel? Who says you need to use liquid fuels? Try solids that can be lit and relit in space. The fuel cores could be sent on shuttles without as much worry about volatility than liquids. There is one way to stop a burn in space--stop the oxidizer (you're in vacuum, figure it out).
Hmm. I'm not sure it's that easy. I'm pretty sure that solid-fuel rockets have the oxidizer mixed in with the fuel and are fully self contained. The SRBs on the Shuttle, for instance, have nothing pumping an oxidizer in.
There are (in my experiences) two types of propulsion engineers--those who love solid fuels, and those who hate them.
On the positive side, it keeps you from messing with those nasty hypergolic fuels like hydrazine.
On the negative side, once you light it, there's no easy way to stop it until it's out of fuel--it's like a big highway flare. IIRC, if the shuttle needs to abort early in the launch sequence, the only thing to do is to jettison the SRBs and let them go flying merrily on their way (to be destroyed later by range safety).
Liquid fuels can be throttled or shut off. A solid booster's thrust can only be controlled by how the fuel is poured in the casing (star patterns and whatnot give high initial thrust, then back off), and not easily shut down.
Yes, hydrazine + IRFNA is a nasty combination... but still it is easier to handle than LH2 + LOX. You don't need to cool it, it doesn't vaporize off, and because it is hypergolic you will never find yourself pumping 'nasty' stuff into a combustion chamber where there is no burning going on.
There are no 'safe' rocket fuels. But in space (rather than inside the biosphere) hydrazine is manageable just fine.
Given its high orbital inclination, ISS isn't the ideal first stop, but it's still possible to go places. In a simulator, I've gone from ISS's orbit to the moon without changing inclination. It looks scary, but really it's no worse than any other trans-lunar-injection. As for fuel cost, well, the simulator gives you a huge fuel budget but the non-coplanar transfer orbit is still WAY cheaper than changing inclination before heading out! I wouldn't be surprised to learn that the cost is the same.
For a lunar-orbit-rondezvous mission, I can see one potential problem: the possibility of having to wait longer for a launch window from the surface to the command module.
All that said, I kind of like GWB's plan of jumping out of our commitment to ISS as soon as possible. Consider it an experiment in international space cooperation, more than a scientific platform. The experiment is over, lets learn what we can from it and move on.
The Buran flew once, 100% automated and unmanned from launch to landing, at the start of the 1990as iirc. After that, they decided that it was too costly and mothballed the 2 completed and 3 under construction. One is at the Russian National Space Museum, one is in Australia, and the 3 in construction were dismantled. The Energia booster flew a further 3 times, and hasnt been used since due to no need for it (It could have launched the ISS as it stands in 2 or 3 boosts, it could carry a lot.)
Yep, I agree. That's how current solids and liquid fuels work.
But anything is impossible until its not. I don't have a real answer, since I'm just an enthusiast, not an engineer. A solid fuel has to be stoppable--the question is how could it be done and still be relightable? That's a nice new engineering question.
Unfortunately, once the Shuttle SRBs are lit, NOTHING can be done to abort until they are spent. Attempting to let them loose while powered may likely create a Challenger-esque ET destruction sequence, either by collision or imbalanced separations, leaving the Orbiter/ET to tumble.
Oh, yeah. While nice, hypergolics are ugly. But cryogenic fuels are worse.
Vos teneo officium eram periculosus ut vos recipero is.
The ISS is, technically, international since two nations are doing most of it, but what if there were a dozen nations as deeply involved, or a hundred?
Actually, there are 16 Nations participating, so this qualifies for "a dozen", doesnt't it?
Besides that, you are right. The ISS is just a prototype. Talking about its qualities as research lab was just a way to show the investors (taxpayers) some justification for the expense. It was needed to quiet down all those "we have more pressing problems as to catapult stuff into space"-people.
Of course science is a goal, but to think those discoveries will earn back the money invested in a way directly measurable, is absurd.
In the long term there are 2 solutions for mankind:
1. Find a way to stop population growth and base our whole society on resources available in unlimited amounts. Live in equilibrium with our environment. As our economy does only work if it can grow steady (about 2% are ideal) this would be a fundamental change.
2. Do what we did for millenea now: Go out there and expand.
As #1 is not very likely to happen, the question is not whether we can afford to venture into space, but if we can afford not to.
If we do neither, we(as in humanity) will vanish inevitably.
The ISS is just a stepping stone, yes, but as training ground for space engineering, not space expeditions.
Keep open minded - but not that open your brain falls out...
Although the ISS has been marketed from time to time as a "jumping off point", it's not really designed to be one.
Even if we did have a properly designed way station, in the right orbit, at the right inclination, there's an entire infrastructure that doesn't exist. To truly get good use out of a way station, you need specialized space craft, rather than a general purpose pickup truck.
For example, there are very different mission requirements for getting personnel into low earth orbit as opposed to material. It doesn't make any sense to try and use one vehicle, like the shuttle, for both. Material can withstand greater acceleration than people, without the need for life support. So why not have different lifters for people and parts?
Also, any craft that travel from the earth to orbit have certain needs based on the fact that they travel through the atmosphere, and have to reenter that atmosphere. Aerodynamic design, heat shields, etc. These are design features that aren't really anything except for dead weight when you're trying to go from low earth orbit to high earth orbit.
A space tug designed specifically to go from low orbits to high orbits could probably do the job a lot better, and more safely.
High earth orbit also makes a lot more sense as an assembly point. Why would you want to put all your goodies together over the course of time when you still have so much gravity well to climb up out of?
Low earth orbit is also full of junk. I don't know how many pieces of space garbage they're currently tracking in LEO, but I know there's a bunch of it. Why not have your assembly point a little farther out where there's less stuff to put a hole in your mars spaceship?
Of course, if you go out a useful distance, you'll need radiation shielding, a lot more than what the ISS has.
If you're going to be assembling larger craft for manned interplanetary missions, you'll need room to store all your stuff, whether it be vehicle components, reaction mass, consumables, construction crew, whatever. The ISS doesn't have room for any of that junk, even if you through a bunch of inflatable hab modules at it.
The ISS is a laboratory, and it's serving that purpose pretty darn well, despite the fact that it's not even fully staffed or supplied.
Imho, we need a way station, but the ISS isn't it, never was, and never will be.
Previous NASA studies for Mars missions have seldom if ever used the Moon as a launching pad because that would take about twice as much energy as going from the Earth or an Earth outpost.
Here we have a NYT reporter overstepping his limited technical knowledge and making stuff up again.
The best place from which to embark on a Mars mission, in terms of lowest delta-V (i.e. least amount of fuel required), is a high earth orbit. Second best is from the moon's surface. The worst, by far, is from Earth's surface.
For the NYT to say both earth and an earth-orbiting station are superior launch points to the moon is quite ignorant.
IAAOA (I am an orbital analyst).
That that is is that that that that is not is not.