Orion flight postponed

The aims and stakes are high for NASA's Orion spacecraft. All the more reason for caution.

Orion was due to complete its inaugural, four-hour flight on Thursday (4.12.2014). But the mission was aborted after numerous attempts, during a launch window lasting about three hours.

First, a boat had ventured too close to the launch area. Then the winds were too high. Finally, there was a problem with Orion's fill-and-drain valves, and the mission was "scrubbed" for Thursday.

Plans for the future

The US space agency NASA says it plans to use its new type of spacecraft to send humans to asteroids, to re-visit the moon and even travel to Mars.

Most of all, however, Orion is the flagship of a new fleet that will bring the US back into crewed-spaceflight.

Currently, NASA uses Russian Soyuz capsules to send astronauts into space - for example, to the International Space Station (ISS).

If everything goes to plan, Orion will change that. The spacecraft was designed to transport humans into space and bring them back safely.

That's the difference between Orion and automated cargo spacecrafts, such as the Cygnus and Dragon.

Space Shuttle's successor

It's hoped that by 2021 (at the earliest) an Orion spacecraft will carry crew on missions into deep space.

But it might also just make a flying visit to the ISS or another space station to deliver supplies.

There are many possible applications for Orion.

After all, Orion is short for "Orion Multi-Purpose Crew Vehicle."

NASA says the spacecraft is especially designed for long-duration deep space missions of up to six months.

Orion is to replace NASA's Space Shuttle, which had its last flight in 2011.

It resembles its predecessors, the Apollo spacecrafts. But instead of only three crew members, it's been designed to carry four crew members, or even six on shorter trips.

As Orion is intended to return to Earth, it has to be able to endure very hot temperatures during atmospheric entry.

Modular system

Orion consists of a service module, a crew module and a launch abort system.

The crew module is the transportation capsule that houses astronauts, consumables and research instruments.

The service module fuels and propels the spacecraft and stores air and water the astronauts need on long travel through space. It also controls the temperature.

Orion's service module is based on Automated Transfer Vehicles (ATVs) developed by the European Space Agency (ESA), which have delivered supplies to the International Space Station.

The launch abort system, meanwhile, can propel the crew module in the event of an emergency and protects the crew from over-heating.

For Orion's first test flight, it is planned to launch on a Delta IV Heavy Rocket. In future missions, though, it will launch using the Space Launch System (SLS), which is currently being developed.

NASA plans to have the Space Launch System ready for a test flight in November 2018.

It is, says NASA, "more powerful than any rocket ever built."

Two orbits, four hours

On its first flight - the "Exploration Flight Test 1" - the mission will be unmanned.

Over the course of four-and-a-half-hours, Orion will fly two orbits of Earth. The second lap will reach a height of 5,800 kilometers, or 15 times higher than the orbit of the International Space Station.

After that the capsule will - it is hoped - re-enter Earth's atmosphere, decelerate with the help of a parachute and splash down into the Pacific Ocean.

The spacecraft is loaded with sensors to record all aspects of the launch, Orion's flight, its re-entry and landing.