| Space
Shuttles and its Advancements |
Definition
The successful explortion
of space requires a system that will reliably transport payloads into space and
return back to earth; without subjecting them an uncomfortable or hazardous environment.
In other words, the space crafts and its pay loads have to be recovered safely
into the earth. The space shuttle used at older times were not re-usable. So NASA
invented re-usable space shuttle that could launch like a rocket but deliver and
land like an aeroplane. Now NASA is planning to launch a series of air-breathing
planes that would replace the space shuttle.
A Brief History Of The Space Shuttle
Near the end of the Apollo space program, NASA officials were looking at the future
of the American space program. At that time, the rockets used to place astronauts
and equipment in outer space was one-shot disposable rockets. What they needed
was a reliable, but less expensive, rocket, perhaps one that was reusable. The
idea of a reusable "space shuttle" that could launch like a rocket but
deliver and land like an airplane was appealing and would be a great technical
achievement. NASA began design, cost and
engineering studies on a space shuttle. Many aerospace companies also explored
the concepts. In 1972 NASA announced that it would develop a reusable space shuttle
or space transportation programme (STS).NASA decided that the shuttle would consist
of an orbiter attached to solid rocket boosters and an external fuel tank because
this design was considered safer and more cost effective.
At that time, spacecraft used ablative heat shields that would burn away as the
spacecraft re-entered the Earth's atmosphere. However, to be reusable, a different
strategy would have to be used. The designers of the space shuttle came up with
an idea to cover the space shuttle with many insulating ceramic tiles that could
absorb the heat of re-entry without harming the astronauts.
Finally, after many years of construction and testing (i.e. orbiter, main engines,
external fuel tank, solid rocket boosters), the shuttle was ready to fly. Four
shuttles were made (Columbia, Discovery, Atlantis, Challenger). The first flight
was in 1981 with the space shuttle Columbia, piloted by astronauts John Young
and Robert Crippen. Columbia performed well and the other shuttles soon made several
successful flights. The space shuttle consists
of the following major components:
" Two solid rocket boosters (SRB)
- critical for the launch
" External fuel tank (ET) - carries fuel for
the launch
" Orbiter - carries astronauts and payload The
Space Shuttle Mission A typical shuttle
mission lasts seven to eight days, but can extend to as much as 14 days depending
upon the objectives of the mission.
A typical shuttle mission is as follows:
1. Getting into orbit
1.1 Launch - the shuttle lifts off the launching
pad.
1.2 Ascent.
1.3 Orbital maneuvering burn.
2. Orbit-life in space.
3.
Re-entry.
4. Landing.
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