Hayabusa To Begin Long Journey Back to Earth

Sparky writes "Japan is planning to set the Hayabusa spacecraft on a trajectory back to Earth next month after a delay of more than a year, but it's far from certain that it will get back safely. It was supposed to retrieve asteroid debris, but it's thought that a computer error prevented that from happening. A fuel leak means that its chemical thrusters are out of action, and the craft is relying on its weaker ion engines. The journey back will take 3 years, and the capsule will be on Earth in June 2010 — even if it is empty."

Comments

Re:obligatory

[stratjakt]

Ryu Hyabusa is the Ryu from Ninja Gaiden, not related to the Ryu from Street Fighter.

Maybe we need a 40 page Wikipedia entry to clear this up.

Re:Why not park it in high orbit?

[The MAZZTer]

As the summary clearly indicates, they're not 100% sure wtf is up with it. Bringing it back allows them to figure that out, as well as collect any asteroid debris it might have successfully picked up. In addition, they'll be able to track down the computer error to avoid it occurring in future craft. Same with the fuel leak.

Correction

[kahrytan]

Ion Drives are not slow. And Japan is probably most interested in how the drives perform.

From Deep Space 1;

The ultimate speed of a spacecraft using ion thrust depends upon how much propellant it carries; indeed, the same principle applies to chemical propulsion systems, although they are much less efficient. The ion propulsion system on Deep Space 1 carries about 81.5 kilograms of xenon propellant, and it takes about 20 months of thrusting to use it all. It increases the speed of the spacecraft by about 4.5 kilometers per second, or about 10,000 miles per hour. If we had the same amount of chemical propellant, it would provide only one tenth as much velocity increment. If DS1 carried a larger solar array, it certainly would have a slightly higher acceleration, and if it carried more Xe propellant it could reach a much higher final velocity by simply thrusting longer. But DS1 is testing ion propulsion solely to find out if it works as well as predicted. Future missions that use it likely will carry more propellant to achieve still higher speeds.