Philae Has Landed!

Congratulations to the European Space Agency for successfully landing the robot probe “Philae” on comet 67P!  The lander, which is about the size of a washing machine, made a soft touch-down on the comet at 3:30 a.m. Brooklyn time. The comet itself has a diameter of four kilometers (2.5 miles) meaning it is approximately as wide as the Verrazano Bridge is long.  To bring such objects together as they hurtle at ridiculous speeds through the vast darkness of space is a tremendous feat of engineering.  Ferrebeekeeper described the long and complex journey of Philae’s mothership, Rosetta, in this previous post.

An artist’s mock-up of how the probe might look on the comet’s surface (the underdressed astrophysicist is added for scale and is presumably not there)

Philae is equipped with space harpoons which are designed to fire into the comet’s surface–thus securing the craft to the flying iceball with lamprey-like tenacity. Actually, a lamprey might be the wrong comparison: the lander looks astonishingly like a bacteriophage (a fact which I think is exceedingly strange and funny). At any rate, it is presently unclear whether the landing harpoons correctly deployed into the comet’s surface.  We’ll know more in coming days.

Indeed, in coming days we should be finding out lots of things regarding the comet.  The lander has a small drill which is meant to mine 20 cm (8 inches) into the icy substrate.  The sophisticated machine is also equipped with devices to analyze the core sample, gas analyzers to identify any complex organic compounds, and instruments to measure the comet’s magnetic field.   Scientists will be keeping a close eye on the comet to see what effect the solar wind has on it as 67P sweeps in close to the sun in coming months.

November 13th UPDATE:  It seems the plucky lander had a more adventuresome landing than yesterday’s rosy headlines may have indicated.  Apparently Philae landed not once, but multiple times as it bounced down a cliff and fetched up (on two of three legs) in a shadow.  Mission controllers are contemplating whether to fire the landing harpoons, but are concerned that the resultant explosion could send Philae careening off the comet into the outer dark.  Anyone who has thrown a washing machine down an ice cliff in low gravity will surely sympathize with their predicament…