120 seconds in Pluto’s shadow
A nerve-wracking path correction put a 747 on course to measure Pluto’s skies
SCOPE’S ON A PLANE A 2.5-meter-wide telescope peers through an opening on SOFIA during a 2010 test flight over the Sierra Nevada mountains in California.
NASA
Pluto’s shadow raced across the Pacific Ocean at more than 85,000 kilometers per hour. Planetary scientist Michael Person was on a 747 chasing the shadow, which formed as Pluto passed in front of a distant star. Until last summer, everything researchers knew about Pluto’s atmosphere came from stellar eclipses like this one. But for this June 2015 run, the analysis would get a reality check from the New Horizons spacecraft, which was speeding through the Kuiper belt toward the dwarf planet.
On the night of June 29, Person and his team departed Christchurch, New Zealand, on SOFIA, a jumbo jet fitted with an infrared telescope. Operated by NASA and the German Aerospace Center, SOFIA lofts its telescope, perched within a large hole in the airplane’s side, to an altitude of roughly 12,500 meters, high enough to get above most of the molecules in Earth’s atmosphere that absorb infrared light.
The rendezvous with Pluto’s shadow required precision:
