Orbiters is a 8 letter English word. It's valid Scrabble word worth 9 points. It's valid Words with friends word worth 10 points.
You can make 311 anagrams from letters in orbiters (beiorrst).
An Americanism dating back to 1950-55; orbit + -er1
However, the probe stayed in contact with the Rosetta orbiter and has already sent back some photos.
The basic approach went as planned: after separating from the Rosetta orbiter, Philae coasted slowly to the comet surface.