Without doubt the greatest constraint that the space program has felt since the success of the Apollo program is financial. Apollo was funded because, for various reasons, everyone was behind the project, but this is no longer the case (we shall explore this in more detail in a couple of pages time in: After Apollo: Why has the quest to explore space ground to a halt?).

In 1970 the US had planned to concentrate on a reusable spacecraft and a space station, but the space station was quietly swept under the carpet due to NASA's ever decreasing budget.
Finally in January 1972 President Nixon announced that NASA would begin its program of building the new Space Transportation System (STS), or more commonly the Space Shuttle. This was to be an attempt to build a reusable launch vehicle to replace the 'throw away' rockets. The thinking behind this was that by using a reusable vehicle it should greatly reduce the costs allowing routine space access. This is the first attempt that had been made to address the major problem of space access, i.e. cost (it is thought for every pound to be launched to orbit a cost of up to $10,000 is accrued!).

The idea of developing a reusable plane was nothing original, as early as the 1930's Eugen Sänger (1905-1964) had seriously studied the idea of using winged 'planes' that could take off and land conventionally but fly right up into space. Following his work proposals were suggested in the 1950's and designing proper began in the 1960's. The immense effort of the Apollo program, however, was to leave this idea filed away until 1972. The original plans for the Shuttle where for a fully reusable spacecraft that could fulfil the commercial missions to operate as a Spaceplane (i.e. a conventional aircraft that could fly into space).

There where however several major problems for this plan almost from the beginning:

• Unforeseen financial constraints
• Continual increase in public apathy
• The resultant waning of political support
• Technological constraints (or design problems!)

The result of these problems was a compromise, the shuttle design became a smaller, semi-reusable launch vehicle, however this seriously compromised effectiveness in its primary objectives (i.e. cost saving).
Nevertheless the Shuttle remains the world's only reusable space vehicle, and holds the enviable status of being the best, cheapest, most efficient and most reliable way for man to reach space. Due to its status the US has frequently used its shuttle fleet for other clients and countries, for a small fee of course!

The Shuttle project is composed of 3 particular parts.

STS' Maiden Voyage Image Courtesy:NASA

1. The reusable orbiter, the part most associated with the project, this is the part that looks very similar to a conventional plane
2. The expendable liquid propellant external tank, the large, central part of the launch vehicle
3. The 2 smaller reusable solid fuel rockets on the sides of the main rocket

So the Shuttle is clearly not fully reusable, indeed externally it seems to take off in the same manner as rockets before it, a far cry from the original ideas of the plane taking off from a runway and flying into orbit. The two solid fuel boosters burn for around 2 minutes before being jettisoned and this are recoverable and may be reused. The main engines fire from lift off right until the Shuttle reaches orbit where the tank is jettisoned and it will fall back to Earth burning up in the atmosphere. Once the mission is complete the craft simply re-enters the atmosphere and then acts as a glider, sailing down to finally land in a conventional way on a runway, this part is fully reusable.
The Shuttle's maiden voyage occurred in 1981.

The Shuttle has proved very successful in its missions in space, these are extremely varied, demonstrating the excellent versatility of the craft:

• Transporting people: such as the docking procedures with the Russian space station Mir, and more recently transporting them to the International Space Station.
• Transporting materials, such as the components to be put together to build the International Space Station
• Transporting spacecraft both into orbit and in retrieval. Such spacecraft could be telecommunication satellites, Earth observation satellites (e.g. to monitor levels of air pollution) or space probes/sensors (e.g. for astronomy, planetary research or even exotic work like space plasma physics) etc.
• The Shuttle allows astronauts to use it as a platform to service and repair satellites and observatories in space, such as the repair of the Hubble Telescope in December 1993
• The Shuttle may be used as a platform for scientific research, in conjunction with NASA the ESA developed 'Spacelab', a pressurised research laboratory that can be loaded onto the Shuttle. The first flight with Spacelab occurred in November 1983. The most common use of Spacelab is micro-gravity research. Microgravity allows increased size and purity of grown crystals which is of interest to materials science and the electronics industry. Large protein crystals are of interest to the science of biochemistry for designing drugs as well as cellular and biology research for medical advances. Studies in microgravity can also be in the form of medical research aimed at finding out more about how people can live and work in space. It also provides a good environment for fluid science research as there is no need for containers!
  Microgravity research could be of great importance and is one of the main objectives of the International Space Station.

There have been two major disasters in the shuttle program in less than 20 years, Challenger in 1986, and Columbia in 2003.

Challenger Disaster

After 24 successful flights came the Challenger disaster. The Shuttle launched at 11:38:00 am EST Jan 28 1986 and 73 seconds later exploded claiming the lives of all 7 crew and the vehicle. The space program was virtually halted for almost 2 years following the disaster, as NASA found and fixed the failure that caused the accident as well as making strides to improve the general safety and reliability of the Shuttle. Since full mission quota resumed in 1988 there have been between 2 and 9 missions every year.

The Columbia Disaster

The more recent Space Shuttle Colombia disaster has shocked the world once again, tragically highlighting the dangers that remain in our quest to explore space.
Details of this tradegy are still somewhat scare, but it appears that the mission could have been doomed from the start. During the launch a small piece of material fell and hit the shuttle. It was felt that the damage was nothing to be concerned with, but it appears that the heat resistant tiles that protect the shuttle on re-entry could have been damaged and tragically were unable to protect the shuttle from the incredible heat that is generated on re-entry.

It is also too early to tell what the possible effects that this disaster could have on the exploration of space are, certainly the manned exploration program will be put on hold and at the time of writing the shuttle fleet is grounded indefinitely. It is probable the delay to the space program will be fairly substantial.

We shall remember those brave astronauts that lost their lives in both of these disasters.

The Shuttle has been a great success in many ways, all of the missions that the Shuttle provides are crucial and it has been a great success in these missions. It must be said, however, that it has not lived up to expectations in fulfilling its initial objective of greatly reducing the costs of space flight, although that is not to deny that costs have fallen, it is just the fall has not been as dramatic as was hoped. The Shuttle has also been subject to spiralling development costs, it still uses masses of extremely expensive fuel and of course is only semi-reusable.
It is generally felt that the Shuttle has not been able to fly as much as expected which has also contributed to its failure to provide low cost space travel.
It is likely that the Shuttle is a step towards the future where a fully reusable Spaceplane will be built.

Go on to Space Station History
Go back to the Contents Page