What are the space shuttle orbiters

Space shuttle

To orbit and back

The construction of the International Space Station ISS would have been unthinkable without the space shuttles as heavy-duty transporters. Nevertheless, the shuttle is not a pure success story. The program was accompanied by tragedies from an early stage and the airfare exceeded all initial expectations.

When the "Columbia" set out on its maiden flight as the first shuttle on April 12, 1981, it was also the first ever reusable spaceship. By 1985, the "Challenger", the "Discovery", the "Atlantis" and - after the "Challenger" explosion in 1986 - the "Endeavor" sent further space shuttles into use in 1992.

NASA officially calls the space shuttle the "Space Transportation System" because it consists of other parts besides the space glider. In addition to the orbiter - the actual space shuttle - there are two solid rockets as starting aid and the large, external fuel tank to which the spacecraft is attached when it is launched.

The two rocket engines land with parachutes in the sea and are then rescued by ships. The tank is the only component that cannot be reused and burns up in the atmosphere after start-up.

Workhorse in the service of space travel

The astronauts on the moon missions were still recruited from former combat pilots and test pilots. The Apollo program brought only one scientist to the moon in six moon landings: the geologist Harrison Schmitt.

The space shuttle, on the other hand, was tailored to the needs of modern space travel and was intended to give science better access to space.

The big goal: to set up and operate a space station. There, astronauts should gain long-term experience in orbit and be able to conduct systematic research under space conditions.

The shuttle seemed ideally suited for setting up and supplying a station. With a wingspan of almost 24 meters and a length of around 27 meters, it was as big as a smaller jet. Since its inception, it has been the largest spaceship available and extremely versatile.

It can simultaneously bring a crew of seven astronauts and a massive payload of 24.5 tons into low Earth orbit. As a result, it was previously not only able to transport heavy modules to the space station, but could also be used for special missions such as repairing and, if necessary, returning satellites.

The explosion in costs

The reusable shuttle should also significantly reduce the costs of flights into space. It should also be attractive for the military and private clients and transport satellites into orbit in a kind of shuttle traffic.

But the original cost estimates turned out to be an illusion. Instead of the 10.5 million dollars actually planned, a flight, according to NASA, recently cost almost 50 times as much: around half a billion dollars.

The problem: At the beginning, weekly starts were planned, but the shuttles only took off every quarter. Because they were manned, the shuttles had to meet higher security requirements than unmanned rockets. The starts were dependent on good weather, which repeatedly led to start delays - often several times in a row.

In addition, the maintenance of the orbiters turned out to be very time-consuming and so the shuttles could not be made ready to fly at short notice like a commercial aircraft. NASA manager Jesco von Puttkamer is quoted as saying that the space shuttle was technically successful, but failed financially.

For the mass transport of satellites into space, the shuttles were ultimately too unreliable, too expensive and also a little oversized compared to single-use rockets. Because their enormous payload capacity has rarely been fully exhausted.

1986 "Challenger" explosion

The shuttle program was accompanied by tragedies early on. A defective sealing ring when the "Challenger" took off on January 28, 1986 led to a disaster less than three years after its maiden flight in April 1983.

Just 73 seconds after take-off, the space shuttle exploded at a height of around 14 kilometers. All seven astronauts were killed. It turned out to be fatal that the space shuttle did not have a rescue system, unlike, for example, the Russian Soyuz spaceships.

After the accident, the shuttles remained on the ground for more than two and a half years so that the incident could be investigated and countermeasures initiated.

The management, which was under pressure due to take-off delays, forced the "Challenger" to take off despite warnings from the technicians. Therefore, after the accident, NASA changed the decision-making processes and also replaced the critical seals.

As a replacement for the "Challenger", the shuttle fleet was increased by building the $ 1.7 billion "Endeavor". In the fall of 1988, the shuttles started operating with a greatly reduced flight schedule. The shuttle program was no longer available for private clients; only scientific space missions were carried out.

2003 Columbia accident

Despite all the improvements after the "Challenger" explosion, the shuttle flights into space remained a dangerous undertaking. A study from 1995 put the risk of another shuttle accident at 1: 145 - the statistical mean one crash fell on 145 flights.

On February 1, 2003, the second catastrophe in the history of the space shuttle occurred on the return flight of the "Columbia", which revealed another weak point. A broken piece of foam from the insulation of the outer tank had destroyed some heat protection tiles on the left wing leading edge during take-off.

When they re-enter the atmosphere at around 30,000 kilometers per hour, the space shuttles are exposed to extremely high temperatures, in some cases 1,600 to 1,800 degrees Celsius.

The hot plasma penetrating the unprotected wing probably destroyed the supporting structure, so that the space shuttle broke apart 63 kilometers above the ground and mostly burned up in the atmosphere.

"Return to Flight"

After the "Columbia" accident in spring 2003, the shuttles had to take a two-and-a-half-year flight break, as they did after the "Challenger" explosion. During this time, Russian Progress and Soyuz spaceships took over the supply of the International Space Station, which for so long was only operated with a two-man emergency crew.

NASA invested around a billion dollars in additional security measures for the space shuttles. After the tragic experiences with the "Columbia", the engineers developed control and repair options for the heat shield in space and improved the stability of the outer tank insulation.

But when flight operations resumed in July 2005 under the motto "Return to Flight" there were problems with the tank insulation again. When the "Discovery" started, a larger piece of foam came off again and only just missed the space shuttle.

After this setback, the shuttle fleet only flew into orbit for a few urgent missions - to complete the International Space Station and to repair the Hubble space telescope again.


The space shuttle was not just a means of transport, but also served as accommodation for the astronauts when they were in space for several days. In the cargo bay, the space shuttles initially dragged the European space laboratory Spacelab into orbit. The astronauts circled the earth for about ten days and were able to experiment in weightlessness.

After the first test flight in 1983 with Ulf Merbold on board, two Spacelab missions monitored by Germany took place: In 1986 Ernst Messerschmid and Reinhard Furrer were on the German D1 mission.

In 1993 Ulrich Walter and Hans Schlegel followed on the D2 mission with the space shuttle "Columbia", during which they carried out 88 experiments, including experiments on the effects of weightlessness on humans.

Hubble telescope

Compared to other spaceships, the space shuttles were extremely versatile. They gave astronauts a unique opportunity to approach and repair orbiting satellites. The maintenance work on the "Hubble" space telescope is certainly one of the highlights in shuttle history.

The space telescope orbits the earth at an altitude of around 600 kilometers, where it is not susceptible to atmospheric disturbances. In orbit, spectacular images of galaxies at the edge of the universe and the detection of black holes in the core of many galaxies were made.

After the telescope went into orbit on board the "Discovery" in April 1990, it initially only provided blurred images due to a manufacturing defect on the main mirror.

Only the correction by an additional lens system during the first maintenance mission with the space shuttle "Endeavor" in December 1993 made the sensational images of distant stars and galaxies possible. The shuttles flew to the space telescope a total of five times to exchange parts and even to upgrade it technologically.

Mammoth project ISS

When the space shuttle was being developed in the 1970s, NASA already envisaged deployments to build a space station, and the almost 40 missions to the international space station ISS from 1998 will certainly be the main task in the second half of the shuttle program. Again and again Since then, modules have been transported into space and put together in complex and not harmless spacecraft missions.

The construction of the station, which cost more than 100 billion euros, relied on the shuttles as heavy-duty transporters. No other spacecraft could have carried the heavy, large modules. When the shuttles stayed down after the "Columbia" accident in 2003, unrest spread across Europe as well.

The transport of the European space laboratory "Columbus", into which more than one billion euros in development costs had flowed, was initially postponed for an indefinite period.

But worries about the future of the research module were unfounded. After the resumption of shuttle flights, Columbus docked at the ISS in 2008, as did the largest single module of the space station, the Japanese Kibo laboratory.

The end of the space shuttles

In November 2012, the era of the space shuttles ended. One after the other, the oldest space shuttle "Discovery", then the "Enterprise", the "Endeavor" and finally the "Atlantis" were taken out of service and pushed into the museum.

The reason for the end of the space shuttle program was the high cost. Since then, the USA has been dependent on Russia for flights to the International Space Station.