The Hubble Space Telescope Time Allocation Committee has recommended using the Hubble Space Telescope to search for an object the Pluto-bound NASA New Horizons mission will be able to visit after its flyby of Pluto in July 2015. Scientists involved in the much-awaited Pluto encounter have wanted to send New Horizons onward to explore an object beyond Pluto in the Kuiper Belt, but, so far, no suitable object has been found. That’s why the Hubble Space Telescope is being recommended for use in the search. If an object beyond Pluto can be found for New Horizons, it’ll be the most distant object yet visited by an earthly spacecraft.
The planned Hubble search will involve targeting a small area of sky in search of a Kuiper Belt object (KBO) for the outbound spacecraft to visit. The Kuiper Belt is a vast debris field of icy bodies left over from the solar system’s formation 4.6 billion years ago. A Kuiper Belt object has never been seen up close because the belt is so far from the sun, stretching out to a distance of 5 billion miles into a never-before-visited frontier of the solar system.
Matt Mountain, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland said:
I am pleased that our science peer-review process arrived at a consensus as to how to effectively use Hubble’s unique capabilities to support the science goals of the New Horizons mission.
Fully carrying out the KBO search is contingent on the results from a pilot observation using Hubble data. The space telescope will scan an area of sky in the direction of the constellation Sagittarius to try and identify any objects orbiting within the Kuiper Belt. To discriminate between a foreground KBO and the clutter of background stars in Sagittarius, the telescope will turn at the predicted rate that KBOs are moving against the background stars. In the resulting images, the stars will be streaked, but any KBOs should appear as pinpoint objects.
If the test observation identifies at least two KBOs of a specified brightness it will demonstrate statistically that Hubble has a chance of finding an appropriate KBO for New Horizons to visit. At that point, an additional allotment of observing time will continue the search across a field of view roughly the angular size of the full moon.