why was the spaceshuttle designed to come back to earth without power ?

Question

would'nt it be an advantage to have power on re - entry ?

Answer 1

The shuttle was originally designed with jet engines on the wings for re-entry power, but I'm not sure of the reason they were dropped. Knowing NASA (I worked there 10 years) probably budget consdierations - same reason the dropped the ejectable crew compartment - now that would have come in handy at least once.

Answer 2

It was designed as a lifting body, basically as a flying brick to glide back down to Earth. Once it is launched into orbit, gravity will pull it down to a lower altitude where it will eventually encounter enough friction to cause a rapid reentry. The shuttle can change its attitude to reposition its underside to provide a lot of drag from the Earth's atmosphere so the re-entry can be controlled and it can glide down a runway.

A controlled burn re-entry design would require onboard retro-rockets, would greatly reduce the lifting payload capacity of the shuttle and/or increase the amount of fuel needed to launch it into intitial orbit.

The Apollo program's lunar excursion modules (LEM) did have re-entry (as well as launch rockets) to land on the Moon because the Moon does not have a drag-inducing atmosphere.

Answer 3

The shuttle has power just no propulsion, When the shuttle is in orbit it uses a burst of air to move around, remember there is no friction in space, the shuttle is doing about 18,000mph or one revaluation around the world every 80 minuets. when the shuttle re enters the earths atmosphere it is just falling, all of it's fuel was used to get into orbit, the big Orange tank is what holds all the fuel, the booster rockets burn off of that same tank, once it's jettisoned then the shuttle burns the last of it's on board fuel to get into orbit. It is also safer for then to have no fuel on-board when in re entry fuel is a liquid which could slash around causing the shuttle to move around more then necessary. I hope this helps answer your Question.

Answer 4

Energy (fuel) plays an important role in making it possible to get into an orbit along with some payload. every extra-pound of fuel on reentry would mean buying this advantage with lots of extra-pounds of fuel on liftoff.
i don't know any imaginable advantage of having fuel left after re-entry.

Answer 5

As it is, the weight and velocity of the shuttle barely scrapes by the heat ofre-entry.

Adding fuel would add weight and velocity, and don't have the tecnology to compensate for the added heat.

Answer 6

To get it light enough to make the trip at all. All that extra feul would require more power to lift it into orbit.

Answer 7

It would need more power to lift the fuel.

Answer 8

gravity is enough