HOW ABOUT AN ASTEROID OR WOULD YOU BELIEVE A COMET

Yesterday (November 12, 2014) the European Space Agency (ESA) spacecraft Rosetta landed a package (Philae) on a comet (67P Churyumov-Gerasimenko).*  It was a very complex mission just to get to the comet.  Periodically I have been ready to break out in tears all day (the 13th).  In the early 1970s I was a member of a working group in NASA on Missions To Comets And Asteroids.  I’ve waited more than 40 years for this.  The ESA had a good mission to Halley’s Comet in 1968, but a mission by the U.S. couldn’t be sold.  The Japanese and Russians also had less sophisticated missions.  The U.S., however, did have a space craft reprogrammed to fly though the tail of Halley’s.  This sort of completes things for me, especially if the measurements planned are taken.  It didn’t happen on my time table, but it happened.  I’m glad to have lived long enough to experience it.

The lander is not a total success in that its anchoring did not work (so drilling is perhaps impossible) and it is in the shade of a cliff for now.  As it goes around the sun, perhaps it will get some illumination.  Still  many measurements will be made before its primary batteries run out.

Previously, the NASA spacecraft NEAR Shoemaker landed on the near-Earth asteroid 433 Eros, though it was an orbiter and was not designed to land.**  It was able to collect some valuable information, however, from its gamma-ray spectrometer for a couple of weeks.

My participation in the working group of Missions To Comets and Asteroids was probably the most exciting two years of my life.  We would ask the trajectory engineers (trajectory shapers) what kind of a mission we could have in, say, 1983 and a month later we would come back and these engineers would say something like you could go by asteroid such and such, comet thus and so, and rendezvous with comet whatever.  We had a hard time selling missions to small bodies comets and asteroids so the idea was if we could put several together it would be more sellable, but at the time it didn't work.  We did have some successes, however, with targets of opportunity.  A dust storm on Mars permitted pictures to be taken of the two satellites of Mars (Phobos and Deimos) and a storm on Jupiter enabled pictures to be taken of satellites on Jupiter, including the near Jupiter satellite Io where active volcanoes were observed (see the poem Io at http://stopcontinentaldrift.blogspot.com/2011/07/io.html).  Over many years, NASA was to become somewhat more interested in small bodies, perhaps because of the engineering challenges that supplied in getting to them.  I was to learn about all sorts of space tricks like Jupiter gravity assists in getting space craft to these small bodies.  .  (The report of the panel was published as Stuhlinger et al., Comet and Asteroid Mission Study Panel, l972, Comets and Asteroids:  A Strategy for Exploration:  NASA Technical Memorandum, NASA TM X-64677, 93 p. [where I was one of 11 authors])

* (http://www.huffingtonpost.com/2014/11/13/comet-picture_n_6150592.html)
** http://science.nasa.gov/missions/near/