Successful Failures

Apollo 13 commander Jim Lovell considered his mission -- in which a crippled spacecraft did not land on the moon as planned but did return its three astronauts safely to Earth -- a "successful failure."

A couple more successful failures are working to gather scientific knowledge right now. The former THEMIS P1 and P2 probes, in danger of shutting down because their orbits don't allow enough sunlight to their solar panels, have been redirected to study conditions around the moon instead. The THEMIS satellites are not technically a failure, because they worked in conjunction with the other probes in their five-spacecraft set to gather much of the data they were supposed to. But the change in their orbits over time left them in shadow too long for their systems to recover, and they were in danger of freezing out. Vassilis Angelopoulos of UCLA, principal investigator of the THEMIS mission, referred to them as "dead spacecraft walking," which is kind of a clunky phrase that draws on a 15-year-old movie title and shows that some folks aren't cut out for marketing.

Renamed the ARTEMIS mission, the two satellites will now explore the effect of solar wind on the moon and at the Earth-Moon Lagrange points. These are places in space where the gravitational interaction of the sun, moon and Earth combine to keep an object in one place relative to those bodies. A spacecraft in the Lagrange point would have to use very little fuel to keep its station, compared with one in some other position. Also, according to Messrs. Gibbons, Hill and Beard, "they gotta lotta nice girls there," although that idea "...might be mistaken."

Over on Mars, one of the two Spirit Rovers that have been tooling around the Barsoomian landscape since 2004 has found evidence of water that may have flowed underneath the Martian surface. Again, the rovers are not truly failures, as they have been working several years past their initial three-month mission plans. But the Spirit rover got stuck in some Martian sand a few months ago and is in a hibernation mode while it awaits the Martian spring and maybe gets some sun on its own solar panels and can get working again.

But before it shut down, it sent data that showed strata, or layers, in the Martian soil that suggests snowmelt flowed underneath the top crust not very long ago. If Spirit survives the bitter cold of the Martian winter and does begin to operate again, scientists plan to test several things about the soil around it that can be done without getting the little goldbrick to up and move again.