Phobos-Grunt, the Russian probe that should be on its way to Mars but is instead parked in Earth’s orbit, could fall back down to our planet with a bang in the next few days. And the uncontrolled return of the ‘toxic probe’ is particularly worrying since it contains a small quantity of radioactive cobalt-57.
If Phobos-Grunt falls as expected, it will mostly break up in the atmosphere. But parts will survive and it’s not clear yet where they’ll land. As well as the cobalt-57, Phobos-Grunt also contains ten tons of fuel and oxidizer in the form of unsymmetrical dimethylhydrazine and nitrogen tetroxide. In other words, this isn’t something you want landing on your head.
Russia’s space agency is poised for a series of reforms after this latest, embarrassin failure. Efforts are still ongoing to try to get control of Phobos-Grunt, but it now looks increasingly likely that the probe will land somewhere on November 26th or shortly thereafter.