NuSTAR satellite approved for further study by NASA
The NuSTAR satellite will image high-energy X-rays, giving scientists a new perspective on black holes, supernovae and galactic nuclei. The extendable mast, of which only a small fraction is shown here, will extend to 10 meters once the satellite is launched. (Image courtesy of Bill Craig)
The Nuclear Spectroscopic Telescope Array (NuSTAR) satellite may soon give astrophysicists a new window on the universe. Designed to image high-energy X-ray radiation, it will capture sharp images of black holes, supernovae, and galactic nuclei. And if NASA gives the project final flight approval early next year, it could be in orbit by the end of the decade.
NuSTAR is capable of capturing X-rays in the range of 10-80 KeV, known as the ‘hard’ X-ray band. This is a huge improvement over previous missions, which have only been able to image lower energy, or ‘soft’ X-rays. Since these hard X-rays are better able to penetrate the layers of gas and dust in our galaxy, NuSTAR will be able to make observations that were previously beyond reach.
“With this mission, we’ll open the hard X-ray frontier and look at things never seen before,” said project leader Fiona Harrison (Caltech).
The fact that hard X-rays can penetrate matter makes them incredibly hard to focus for imaging purposes. NuSTAR will employ sophisticated reflective surfaces and advanced detection equipment to corral these high-energy rays. In doing so, it will address three main scientific goals.
First, it will take a census of black holes. By looking for their X-ray signatures, NuSTAR will count as many of these bizarre objects as possible. It will also track their accretion rate—or how quickly matter is drawn into them—by imaging the radiation they emit as they grow.
Second, NuSTAR will explore remnants of supernova explosions to study the formation of heavy elements. It will look for titanium-44, which is formed in the region where material either shoots out into space or collapses into the super-dense core. By tracking the decay of this isotope, NuSTAR should discover a lot about the evolution of elements in the universe.
Third, it will investigate the astrophysical jets streaming from the core of galactic nuclei. These strange features remain an enigma to researchers. NuSTAR will make observations in tandem with the GLAST satellite to give a first look at the high energy profile of these cosmic particle accelerators.
“This mission takes advantage of new technology, allowing it to have sensitivity hundreds of times better than previously deployed instruments,” said Greg Madejski (ASG). “It will push the boundaries of what we can see with mirror-based telescopes.”
A high-altitude balloon called the High Energy Focusing Telescope (HEFT) is scheduled to be launched from New Mexico in April. It will carry hard X-ray focusing equipment, similar to that designed for NuSTAR, to test its functionality and readiness for space flight.
Bill Craig (KIPAC), NuSTAR Project Scientist, explained that while HEFT is a useful tool for development and testing, it does have limitations. “A balloon only allows a few hours of observation per flight,” he said. “NuSTAR will operate above the atmosphere for three years, allowing a tremendous advance in scientific capability.”
NuSTAR work at both SLAC and Stanford will be managed by KIPAC. “We at KIPAC are thrilled about being part of NuSTAR,” said KIPAC Director Roger Blandford. “It is our first new project to garner federal funding, and demonstrates how SLAC and [Stanford main] campus can work so well together.”
NuSTAR was selected from among 29 Small Explorer (SMEX) proposals submitted to NASA in response to an Explorer Program Announcement of Opportunity issued in early 2003. The SMEX program specifically seeks out promising scientific missions that can be launched at low cost. If final flight approval is granted early next year, NuSTAR will be scheduled for launch in 2009.
The NuSTAR project brings together collaborators from Caltech, SLAC, JPL, Columbia University, LLNL, UC Santa Cruz, Sonoma State University and the Danish Space Research Institute. The researchers invite participatory inquiries from members of the astrophysics community.
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