The Alice ultraviolet (UV) spectrograph aboard Rosetta has delivered its first scientific discoveries, making the first far ultraviolet spectra of a cometary surface.
Alice is probing the origin, composition and workings of comet 67P/Churyumov-Gerasimenko, gaining sensitive, high-resolution compositional insights that cannot be obtained by either ground-based or Earth-orbital observations.
From data collected over the last month, the Alice team discovered that the comet is unusually dark in the ultraviolet and that the comet’s surface – so far – shows no large water-ice patches. Alice is also already detecting both hydrogen and oxygen in the comet’s coma, or atmosphere.
“We’re a bit surprised at just how unreflective the comet’s surface is and how little evidence of exposed water-ice it shows,” says Dr. Alan Stern, Alice principal investigator and an associate vice president of the SwRI Space Science and Engineering Division.
“As the mission progresses, we will continue to search for surface ice patches and ultraviolet color and composition variations across the surface of the comet,” says Dr. Lori Feaga, Alice co-investigator at the University of Maryland.
Alice was developed by Southwest Research Institute and is one of three instruments funded by NASA flying aboard Rosetta.