The pellet gun failed to fire, three of its four engines have failed, and mission control has lost control of it once already. Already months late, what are the odds that Japanese probe Hayabusa will make it home at all?

New Scientist reports that the Japanese Hayabusa asteroid probe is once more on its way back to Earth after scientists worked out a way to use two of the broken engines together to make... one engine:

One engine is still able to spit out positive ions for thrust, but can no longer squirt out negatively charged electrons, a step needed to prevent electric charge buildup on the spacecraft. The team got around this by spewing the required electrons from a second sick engine that retains this ability.

But even with this "frankensteined" engine, scientists at the Japan Aerospace Exploration Agency aren't confident that the probe will reach the Australian outback destination it was supposed to have reached earlier this month; if all goes well, project manager Jun'ichiro Kawaguchi says, it should return in June next year. But, he adds,


This new configuration is very new to us and we are not sure ... how much we can count on [it].

It's like the little probe that can't.

'Frankenstein' fix lets asteroid mission cheat death [New Scientist]