Slashdot Mirror
Shuttle Set for Launch on Dec 18th, Says NASA
Tony J Case writes "Just a quick note for you guys - According to space.com, NASA's target date for the next shuttle launch is Dec. 18th, with a whole bunch of new guidelines."
← Back to Stories (view on slashdot.org)
Continuing to fly the shuttle,l and explore space is definitely the best memorial they could ever give to the people on Columbia.
Disagree all you want to, I'm just happy that the space program was not ended.
Fly on, NASA.
There is no reasonable defense against an idiot with an agenda
:wq
... to see that this useless vehicle is put back into operation, wasting money that could be spent for good space science and efficient transportation.
A winged vehicle has nothing but disadvantages, except looking nice on TV when landing:
- Wings impose a huge weight penalty
- Re-entry with wings is unstable and requires active control
- Wings are vulnerable due to their large surface
The space shuttle is anything but re-usable. The boosters are not re-used, the tank is lost anyway and after landing, the shuttle is completely dis- and re-assembled.
State-of-the-art expendable launchers can haul people into space (and bring them safely back) at a fraction of the cost: use a ballistic capsule with escape rocket and a parawing for enhanced flexibility during landing.
The shuttle's only purpose is to fly to the ISS. The ISS's only purpose is to justify the existence of the shuttle. For the Hubble telescope alone, the shuttle would never have been built.
People, myself included, have faulted NASA for past mismanagement of safety concerns. But my real concern is that they spend billions upon billions of dollars and employ thousands of the brightest engineers and scientists, and still make some of the stupidest mistakes which cost lives and money, but most importantly time.
They have monopolized space exploration in the US far too long and provided a poor model for the rest of the world to follow, which has stifled innovation. They should be handing out research and exploration grants like the NSF does and performing reviews of the results to determine future funding. Not running a single space program for a single space station. All our eggs in one basket, as it goes.
Arguments about the airworthiness of the space shuttle to me are pointless. It is a big machine with lots of parts and carries some risk of failure. It has been show to be able to fly successfully a high percentage of the time. Nothing they do to it will fundamentally change that situation. But by being the only game in town there can be no comparison of risk and no judgements made based on that comparison.
NASA asks us, either fly or do not fly. This is not a free choice, to those of us that wish to see humans fly it means that we must choose the space shuttle regardless of risk or incompetence or anything.
NASA will undoubtedly want more money to increase the safety of the space shuttle flights, but to what end? Any machine can be better maintained or operated, if we collectively choose a single means, and spend our collective resources and will on that means we could be on a fools errand. Like driving a car into the ocean. Sure we can keep tuning our procedures and plugging the leaks, but it ain't gonna get us to the other side. So that basic questions of design or operation are essentially meaningless when one only tries or has a single means. Like voting for the only candidate, the choice presented to us is meaningless. To go or not to go. To live or to die. Of course we must go, as we must live.
Or do we? Maybe, when such a stark choice is put before us we must refuse to make it. Refuse the question. Should the shuttle fly or not? Ignore the question, it is inconsequencial to that which many of us care about. Space exploration is the purpose and the question, not the shuttle.
Exploration of space is dangerous and will not survive safety concerns of collective action. Liken it to any human endeavor of significant unknown and danger and you will find it must be done by individuals. Individuals that have clarity of vision and certainty of purpose. It must be done by people, not by institutions or incorporations. People who know the risks, people that see the dangers, people that take the leap because they see the oppurtunity. People that learn and reason.
If we are to keep NASA at all, then it must only be to find those people and give them a little bit of money or help. Like Queen Isabella giving Christopher Columbus enough money to get the supplies and men he needed. Not too much money though, because we know that to succeed in Space one will have to travel lightly, and the tendency of people with too much money is to buy things. We know that to succeed in space one needs to be quick, but the tendency of people with too much money is to spend time spending money.
I expect the shuttle to fly again, because there are a lot of people who depend on it for their livelyhood. I expect that the shuttle will fly again because looking at the world a certain way, it makes sense to continue to do what we have been doing for the last two decades. I expect the shuttle to fly again because it is a link in a chain that could mean the end of the space station. Because it would mean the end to an entire generation's way of thinking.
So there it is, the heads of NASA would like us to choose between their shuttle and nothing. Between the aspirations of mankind and bondage to this rock. It is a false choice.
Oh yeah, that's about the brightest idea I've ever heard. SRBs should have NEVER been rated for manned spaceflight...once they're running, they're running, and that's it. No throttling. No kill-switch. You wait until the propellant is gone.
As for the SSMEs not having much to do with getting the orbiter into space I say this: uhhhhh, what?
Here's a great site that explains the physics of the SRBs. Before this page gets Slashdotted to hell and back, I'll recap what it says: each SRB produces 3.3 million pounds of thrust, and each one weighs 1.3 million pounds (191,000 pounds dry-weight, plus 1.1 million pounds of propellant). That means the combined pair can lift about 4 million pounds. The shuttle itself weighs 171,000 pounds (empty, with engines), and the external tank weighs 66,000 pounds. So with a little rounding off, you can add 3.75 million pounds to the stack before you have an equal balance between thrust and weight (which will get you nowhere near orbit). The aforementioned external tank carries 1.3 million pounds of liquid oxygen and 227,000 pounds of liquid hydrogen. More neat rounding brings us to 1.6 million pounds of fuel, 2.15 million pounds remaining. Let's assume the shuttle is carrying its max payload -- 63,500 pounds. Leaves us with 2.08 million pounds.
So:
Booster Stack Weight + Fuel: 4.52 million pounds.
Thrust of SRBs (combined): 6.6 million pounds.
Resulting Thrust-to-Weight Ratio: 1.4.
By comparison, a F-15 has a thrust-to-weight ratio of 1.19, giving the shuttle a 15% advantage, when using SRBs alone.
That's right. I haven't forgotten about the SSMEs. When run at 104%, they provide an extra 488,000 pounds of thrust each. That's an extra 1.46 million pounds of thrust. Thus, our 4.52 million pound stack now has a 8.06 million pounds of thrust, resulting in a thrust-to-weight ratio of 1.78, or a 66% advantage over the F-15. Note that these figures are assuming that the SSMEs are run at 104% from ignition (which they're not), but also bear in mind that as the shuttle burns fuel, which it does as a prodigious rate, the overall weight of the stack is reduced while the thrust remains constant, so as the vehicle climbs, it's thrust-to-weight ratio improves, and continues to do so after the SRBs are cut loose.
Now, IANARS (RS = Rocket Scientist), but it seems to me that if we want to scale up the SRBs so that they alone can carry the shuttle into orbit, the weight of the propellant is going to exceed the maximum thrust of the SRBs before you can get enough propellant for the entire burn into orbit.
What I'm trying to say is this: leave the rocket science to the rocket scientists.
blog |