Space shuttle

FedEx

Hi
I would like to have the answers of a few basic questions. I would like to know that in a space shuttle, how is the oxygen level maintained?
How does a space shuttle enter in to the space? Does it just go staright from the earth's atmosphere to the space or it has to follow a certain trajectory?

mgb_phys

You mean oxygen for the crew to breathe?
I assume that for the relatively short duration of a shuttle flight and the low demands of the small crew they just use compressed tanks of oxygen.
The shuttle also uses fuel cells which combine oxygen and hydrogen to make electricity with water as a byproduct.
This probably uses more oxygen than the crew do for breathing! As in earlier Apollo missions the crew uses the waste water from the fuel cells for drinking.

It enters space by basically getting a very large vertical kick from some very big rocket boosters! The earth's atmosphere gradually becomes space, there isn't a definite difference - it just becomes thinner and thinner.
The shuttle follows a particular trajectory mainly depending on it's destination, either the ISS or a particular orbital inclination for a satelite.
The shuttle is limited to a small range of orbits because after it has been launched and dropped the huge rocket boosters it onyl has fairly small weak engines with a limited amount of fuel.

FedEx

Yes, means definetly there is not a definite line which separates the atmosphere and the space, the atmosphere gets thinner and thinner.
If we take the example of space stations, the scoentists and all have to remain there for months. So what about the oxygen supply in a space station

mgb_phys

Yes - space is often arbitrarily taken as 100km altitude but even at the orbit of the moon (250,000km) there are still traces of earth's atmosphere.

The ISS has solar panels to generate power so can use the opposite process as the space shuttle - it splits water (H2O) into Oxygen and hydrogen. The flammable hydrogen is dumped into space.

russ_watters

Most satellites orbit at around 150 miles. You could drive there in a couple of hours if there were highways! Speed is the reason for the big rocket boosters, not altitude, and shortly after liftoff, the shuttle pitches over and flies out of the atmosphere at a shallow angle to gain enough speed to achieve orbit.

Oxygen comes from tanks. The bigger problem is carbon dioxide. The shuttle uses special filters to eliminate the carbon dioxide the astronauts exhale so they don't poison themselves.

'anybody'

what?? they dump the hydrogen? why don't they use it as combustible fuel in generators? they could power batteries for emergency power, and be an aid to the solar panels.

russ_watters

The astronauts need the oxygen to breathe (that's the point of splitting the water), so there isn't any left over to burn the hydrogen for energy.

Astronuc

The rocket boosters provide energy (work) to increase the gravitational potential of the payload (mgh) as well as kinetic energy (and speed) to enable mv²/r. The speed is necessary to maintain orbit once the shuttle or satellite gets to altitude.

The solid rocket boosters simply lift the external tank with the shuttle in the lower part of the atmosphere. Much of the thrust is simply lifting the propellant and structure (SRB's and ET). The ET separates from Shuttle about 30 sec after Main Engine Cutoff (MECO) at an altitude of ~120 km.

http://spaceflight.nasa.gov/shuttle/...events/2stage/

Mission profile - http://science.ksc.nasa.gov/shuttle/...ission_profile

Here is an overview of STS-95: http://www1.jsc.nasa.gov/er/seh/Spac..._Discovery.pdf

ET info - http://science.ksc.nasa.gov/shuttle/...ewsref/et.html

http://www.spaceline.org/rocketsum/s...-boosters.html
http://science.ksc.nasa.gov/shuttle/...wsref/srb.html

For more info - http://science.ksc.nasa.gov/shuttle/...tsref-toc.html