The Rosetta orbiter that recently arrived at comet 67P/Churyumov-Gerasimenko has delivered its first scientific data from the encounter.
Alice, an ultraviolet detector aboard Rosetta, began mapping the surface of the comet in wavelengths more energetic than visible light. This study revealed the massive dirty snowball is darker than charcoal black, ass seen in UV wavelengths.
"We're a bit surprised at just how unreflective the comet's surface is and how little evidence of exposed water-ice it shows," Alan Stern, principal investigator on the Alice program, working at the Southwest Research Institute, said.
The NASA instrument has the ability to gather 1,000 times as much data as those aboard spacecraft flown 30 years ago. Despite this power, the detector weighs just nine pounds and runs on four watts of electricity. A total of 11 complete instruments are included on Rosetta.
Water ice was not seen in any significant quantity on the surface of the comet, an unexpected find for many astronomers who believed the craft would find frozen patches of the material.
Analysis of the coma, or atmosphere, of the comet was shown to be composed oxygen and hydrogen.
The Rosetta spacecraft stretches over 105 feet from one side to another, including the solar panels. The spacecraft was launched in order to study details of the composition and behavior of comet 67P/Churyumov-Gerasimenko that cannot be measured from the Earth.
Philae, a small lander accompanying Rosetta, is scheduled to land on the frozen body in November 2014.
The European space agency manages the Rosetta mission, but Alice is one of a pair of full instruments designed and managed by the American space agency. Groups in the United States also contributed several other components to the Rosetta mission.
The Microwave Instrument for Rosetta Orbiter (MIRO) is designed to examine gas and dust rising from the nucleus, or main body, of the comet. These materials give rise to the corona, as well as the distinctive tails of comets.
The Ion and Electron Sensor (IES), one part of the Rosetta Plasma Consortium Suite, will examine charged particles in the cometary atmosphere.
Rosetta launched on its mission to the comet on 4 March 2004. It performed three flybys of the Earth and one of Mars, changing path and velocity, on the way to the distant body.
Comet 67P/Churyumov-Gerasimenko has a diameter of 2.5 miles, and examination of the body could assist scientists studying the early history of the solar system. They may even learn if life itself may have been brought to Earth from comets billions of years ago.
