Space Shuttle

**Travis Dane** · 02-05-2003

Originally posted by adrianxw
What alternative launch technologies are you thinking about anyway? I am well aware of the different types of engines being developed, (and cancelled willy-nilly by underfunding), and of different fuels being investigated. It is also possible that orbital velocities may be possible with SCRAM jets, (although I do not believe they are in any way safer than rocket engines - rockets have been around for centuries, despite a few cautious claims, I don't think anyone can say for sure their SCRAM worked! The Aussie machine looked interesting - just before it crashed.)

I agree with the fact that current technology developments is
still in it's child phase, But so are rockets, Sure rockets have been
around for a while but they where only used to blow up things,
not carrying people in, Rocket's aren't that safe.

**adrianxw** · 02-05-2003

>>>
a laser or something similar that was projected onto the surface of a piece of metal coated in a substance of some sorts.
<<<

I've not seen the demo you refer too, but, if you shine a very powerful laser onto an non reflective object, yes, you can get a small localised "explosion" as the energy of the laser is absobed. I remember a powerful Q-switched pulse laser blowing a hole in a piece of wood for example. If the wood had not been tethered, the explosion would have produced a force acting on the wood which would have reacted by moving away from the laser source.

A series of explosions behind a big blast shield have been proposed before. The British Daedalus star ship proposal used nuclear pulse drive. The concept has been proven with conventional explosives.

Another approach, once you are in space is to use a large solar sail to provide drive, but this does not work a long way from a star. A variation of solar sailing is to send the sailer off and provide the energy for the sail from orbital GigaWatt lasers, but even then, the inverse square law makes the energy required to drive the things greater distances impractical.

um... · 02-05-2003

Laser Propulsion info:

http://www.google.com/search?q=laser+propulsion

http://science.howstuffworks.com/light-propulsion.htm

Video available here:
http://www.lightcrafttechnologies.com/gallery.html

Scramjet Info:
http://www.uq.edu.au/news/hyshot.phtml

http://www.mech.uq.edu.au/hyper/hyshot/

**adrianxw** · 02-05-2003

NASA is also experimenting with SCRAM jets, search google for "Hyper-X" or "X-43", or look here...

http://www.fas.org/spp/guide/usa/launch/x-43.htm

um.. · 02-05-2003

However, unlike uq, nasa has never achieved in-flight scramjet ignition despite its budget being many, many times greater.

**adrianxw** · 02-05-2003

I thought the UQ project had shown "indications that SCRAM ignition may have occurred". Whatever, I think it is a splendid project.

The X-43 of course, has the drawback of being stuck on a damn Pegasus. You'd have thought Orbital would have got that thing sorted out by now!

**DarkStar** · 02-05-2003

What may have happened to Columbia, is that some of the ceramic tiles which shield the ship from this heat have been damaged or knocked off, and the heat has got at the ship itself, damaging or melting parts of it. If that happens to a critical component, it can break, and cause a catastrophic failure of the entire system, remember, although it does not have orbital velocity any more, it is still going REALLY fast. (A Concorde airliner flies at Mach 2, these guys were doing Mach 18 when it started to go wrong). Loose a bit of wing or similar at those speeds and the thing will simply tumble out of control and break up in a fraction of a second.

There was nothing wrong with Columbia. Columbia was placed into a re-entry angle 12 degrees to the left side by a faulty re-entry navigation algorithim... they never saw this. The left side of Columbia was experincing an aero/thermo dynamic overload, the vehicle was losing structural pieces very early in the game on re-entry.

What ultimately doomed the orbiter was when the tire on the left landing gear exploded.

Somewhere within pages and pages of computer program code written years ago for this specific mission, there was ( and still is ) a fatal flaw.

**dP munky** · 02-06-2003

>>There was nothing wrong with Columbia. Columbia was placed into a re-entry angle 12 degrees to the left side by a faulty re-entry navigation algorithim... they never saw this. The left side of Columbia was experincing an aero/thermo dynamic overload, the vehicle was losing structural pieces very early in the game on re-entry.<<

just for the sake of argument, how do you know this and nasa doesnt? i agree that the leading thery now doesnt seem to hold up....but support your argument

**Sebastiani** · 02-06-2003

Originally posted by adrianxw
>>>
I think they re-enter that fast so that they aren't overly exposed to the heat of the atmosphere, but i'm probably wrong.
<<<

It is the speed of re-entry that creates the friction that creates the heat.

Basically, in space, the orbiter, (or whatever), can, (and have too), travel very fast simply to orbit. Think about it, if you throw a stone vertically up in the air, it falls down again - gravity. Now throw the same stone horizontally, it falls to the ground, but some distance away. Throw it harder, (i.e. give it more velocity), it lands even further away. Now, consider this, if you threw the stone fast enough the stone would start falling to the ground, but the Earth is round, so it falls and falls, but the Earth's surface is "falling away" at the same rate, hence the stone never hits the ground - it has orbital velocity. (In practice you couldn't do this at ground level because the speed needed to acheive orbit would generate so much heat, the stone would vapourise!).

Next problem, the atmosphere. If you move something through the atmosphere, it pushes through the air. The air in front of the object has to rush around the object and take it's place behind the object, in doing so it creates friction, (more correctly called "drag" in aerodynamic terms), which creates heat. If you rub your hand accross a carpet for example, you feel your hand getting warm, rub it faster, you feel it get warmer.

Now, you have a space craft at orbital velocity in space where there is little or no drag, but you want it on the ground at zero speed. You have very little fuel to slow yourself down, because fuel is heavy, so what you do instead, is slow yourself a little, i.e. to just under orbital velocity, and you begin to fall in a long arc to the ground. As you get deeper into the atmosphere the drag, and the friction, increase, hence the the heat, but you also shed velocity since the friction slows you down, it acts a a brake, indeed, this is technically known as "aerobraking".

Now, as long as you can shield yourself from that heat, (which can be thousands of degrees), you get a free braking mechanism, a little fuel to keep the craft at the right angle, but otherwise, the atmosphere is doing all the work.

What may have happened to Columbia, is that some of the ceramic tiles which shield the ship from this heat have been damaged or knocked off, and the heat has got at the ship itself, damaging or melting parts of it. If that happens to a critical component, it can break, and cause a catastrophic failure of the entire system, remember, although it does not have orbital velocity any more, it is still going REALLY fast. (A Concorde airliner flies at Mach 2, these guys were doing Mach 18 when it started to go wrong). Loose a bit of wing or similar at those speeds and the thing will simply tumble out of control and break up in a fraction of a second.

I hope that makes sense. (To those who know more, yes, I know it is more complicated than that in practice, but that is essentially what is happening!).

You're right, and the piece that broke off just after launch probably did play a role in this too.

That's a really great explanation well said.

Aerobreaking is not a viable landing mechanism really. It's dangerous and puts unnecessary burden on the ship (and her crew!).

Another idea I had of this was a very large parachute or an array of greater to smaller ones that would deploy one after another. At normal airline altitude it could then fire up the engines and fly in as normal. Parachute technology has become very advanced, and this sort of thing would be easy to implement too.

But things like this are hard to implement buerocratically because they take so long to get from point a to point b.

**Panopticon** · 02-06-2003

Originally posted by adrianxw
Another approach, once you are in space is to use a large solar sail to provide drive, but this does not work a long way from a star. A variation of solar sailing is to send the sailer off and provide the energy for the sail from orbital GigaWatt lasers, but even then, the inverse square law makes the energy required to drive the things greater distances impractical. [/B]

I don't think the inverse square law applies to laser light because the photons output are of equal wavelength and direction. So in theory, a laser beam travelling through pure 'space' would contain the same energy at destination and source.

**adrianxw** · 02-06-2003

This is weird isn't it...

http://www.worldnetdaily.com/news/ar...TICLE_ID=30889

Panopticon:

Even the best lasers have a degree of divergence.

DarkStar:

You don't know anymore than anyone else, what you have there, is a theory.

**DarkStar** · 02-06-2003

Space shuttle Columbia began breaking up very early in the game on re-entry. The orbiter was placed into a bad re-entry angle by the computer program code loaded into the 3 main flight control computers. The code has embedded within it a faulty re-entry navigation algorithm.

The vehicle was experiencing an aero and thermodynamic overload on it's left side. Structural pieces of the left wing began to come off along with thermal protection tiles out over the Pacific ocean.

What ultimately doomed the orbiter was when one or both of the tires on the left landing gear exploded, which caused a catastrophic failure of the by now structurally compromised left wing assembly. At least one of the tires was experiencing an overtemp and excessive pressurization just before telemetry to the vehicle was lost.

Somewhere within pages and pages of program code written years ago for this specific mission there was ( and still is ) a fatal flaw.

One of the astronauts aboard the space shuttle told one of his co-workers at NASA, that if he and the crew were killed on this mission it is because somebody somewhere made a mistake. He told that person to go find him/her and hug them and tell them he holds no ill regard towards them.

His words may turnout to be prophetic.

This is my theory.

**Travis Dane** · 02-06-2003

Originally posted by DarkStar

One of the astronauts aboard the space shuttle told one of his co-workers at NASA, that if he and the crew were killed on this mission it is because somebody somewhere made a mistake. He told that person to go find him/her and hug them and tell them he holds no ill regard towards them.

You can't really blame that person, It's so incredible complicated
to get a shuttle into space, A fault always shows up somewhere,
Just like in Operating Systems

**dP munky** · 02-06-2003

yeah, but i think i'd rather have a b.s.o.d. rather than a tire blow up and tear the wing off of my space craft while falling at mac 18

**Govtcheez** · 02-06-2003

Originally posted by dP munky
yeah, but i think i'd rather have a b.s.o.d. rather than a tire blow up and tear the wing off of my space craft while falling at mac 18

Well, that's just your opinion.