NASA's New Horizons To Use Hubble In Search Of Deep Space Object
June 16, 2014

NASA’s New Horizons To Utilize Hubble In Search Of Deep Space Object

Alan McStravick for - Your Universe online

Update (June 17, 2014): A previous version of this article stated that Charon was discovered by the Hubble Telescope. In fact, Charon was first discovered in 1978 by James Christy of the United States Naval Observatory.

The Hubble Space Telescope has been in near-Earth orbit for 24 years. While its early days were marred by launch delays and the embarrassment of a major flaw in its crucial mirror, since correction the telescope has been able to present amazing images of the observable universe and facilitate space based research by showing things to us we never knew existed. Examples of Hubble discoveries include identifying a new satellite around the planet Neptune, providing circumstantial evidence for oceans on Europa, probing into the magnetospheres of our galaxy's gas-giant planets, and showing the disintegration of asteroids right before our eyes.

Hubble is also used as support for other ongoing missions being conducted in space. From supporting NASA's Mars mission by monitoring seasonal atmospheric changes on the planet to adding its own perspective to the Dawn asteroid mission, Hubble's contributions have been an invaluable asset to scientists whose laboratory is the vast environment that is deep space.

Securing time with Hubble is no easy task, however. An expert committee is responsible for peer reviewing the plethora of proposals that flow in the world over from astronomers hoping to use the telescope to make their observations for their own research projects. Each year, the number of requests received by the committee far exceeds the available observation time. For this reason, they have set up strict guidelines that each request must meet before being considered. For example, proposals must address significant astronomical questions that can only be addressed with Hubble's unique capabilities, and are beyond the capabilities of ground-based telescopes. The proposals that make it through the committee process are then forwarded as recommendations to the Space Telescope Science Institute Director as a balanced program of small, medium and large investigations.

This week, the Hubble Space Telescope Time Allocation Committee announced they are recommending the use of Hubble to support the NASA New Horizons mission once it has completed its flyby of Pluto in July of next year. The proposal they are recommending will have Hubble searching the heavens for an object in the Kuiper Belt that can be visited and observed by the outbound spacecraft. A Kuiper Belt object (KBO) can be any icy body that comprises the vast debris field that was left over as a result of the solar system's formation 4.6 billion years ago. With Hubble's help, the New Horizons mission will be the first spacecraft to ever observe a KBO up close. The belt itself stretches over a five-million-mile span into a never-before-visited frontier of the solar system.

"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," said Matt Mountain, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.

Fully carrying out the KBO search is contingent on the results from a pilot observation using Hubble data.

To undertake this search, Hubble will aim its keen and perceptive eye in the direction of the constellation Sagittarius to hunt a KBO. The range and distance of this search would make looking for a needle in a haystack look like child's play. The research team states they will have Hubble turn at the predicted rate the KBO's are moving in relation to the background stars in Sagittarius. Images Hubble will return to Earth will therefore show the stars as long streaks while the KBO's should appear as pinpoint objects.

In a test observation scheduled to see if Hubble will be able to assist the New Horizons mission, Hubble will need to identify at least two KBO's of a specified brightness. This, say mission scientists, will show that Hubble has a statistical chance in helping to find an appropriate KBO for the mission to visit. If the test observation is successful, the New Horizons mission will be given an allotment of telescope time to continue their search of a field of view that is roughly the angular size of our full moon. Demonstrating the difficulty of the search, an optimal KBO would likely be no larger than the island of Manhattan and will be as black as a briquette of charcoal.

This latest expectation of support from Hubble will not be the first time the telescope has been employed to assist the New Horizons mission. Previously, Hubble was used to discover four small moons in orbit of Plutoas well as having discovered its binary companion object, Charon, likely possesses a subsurface ocean of water. Hubble also identified potentially hazardous dust rings around Pluto.

"The planned search for a suitable target for New Horizons further demonstrates how Hubble is effectively being used to support humankind's initial reconnaissance of the solar system," said Mountain. "Likewise, it is also a preview of how the powerful capabilities of the upcoming James Webb Space Telescope will further bolster planetary science. We are excited by the potential of both observatories for ongoing solar system exploration and discovery."