New Telescope to Bring Black Holes, Exploding Stars Into Focus

This artist's concept of NuSTAR in orbit shows the 30-foot mast that deploys after launch to separate the optics modules, right, from the detectors in the focal plane, left. Photo by NASA/JPL-Caltech.

What heats the sun's outer atmosphere? What makes stars explode? How do black holes influence the growth of galaxies?

These are some of the questions that NuSTAR, NASA's most sensitive, high-energy telescope yet, will aim to answer once in orbit.

NuSTAR, short for Nuclear Spectroscopic Telescope Array, is slated to lift off atop a Pegasus XL rocket on Wednesday from its launch pad at the Kwajalein Atoll in the Pacific Ocean's Marshall Islands, just north of the equator.

Once there, it will focus its X-rays on some of the most violent events in space: energetic particles blasting from black holes and radioactive remnants left over from supernovae, or exploding stars. Its high-energy X-rays will allow it to pierce through massive amounts of dust and gas to see objects that lie behind, invisible to other telescopes.

"It's very penetrating," said Fiona Harrison of the California Institute of Technology, the mission's principal investigator. "We can also observe very hot material in regions where particles are accelerated very close to the speed of light."

NuSTAR will rely on the same kind of high-energy X-rays that a dentist or doctor might use to penetrate skin to study teeth and bones, Harrison said. It will study objects so deep in space and time that they appear as they did when the universe was a quarter of its current age, and from these objects, it will capture images 10 times crisper and 100 times more sensitive than those of any other high-energy telescope.

The image below shows the clarity of NuSTAR's images compared to those taken by existing space telescopes. On the left we see high-energy X-rays taken by the European Space Agency's INTEGRAL satellite. On the right: a simulated view of what NuSTAR would see at comparable wavelengths.

Photo credit: ESA/NASA/JPL-Caltech

The 775-pound telescope contains on one side a set of 133 nested mirrors, each no thicker than a fingernail. On the other side is a detector.

Photo credit: NASA/JPL-Caltech

Once it reaches its orbit, about 400 miles from the Earth's surface, a mast will unfold that stretches the instrument from the length of a basketball player to the length of a school bus. This will separate the mirrors from its two digital detectors about 30 feet away. The mirrors are designed to catch and deflect as much X-ray light as possible toward the detectors, which will focus that light into sharp images.

Despite earlier delays, NASA and weather agencies say prospects so far look good for a Wednesday launch.

"They've said 95 percent clear, and I think that's the best you ever get from the weather guys," Harrison said.

Photo credits: ESA/NASA/JPL-Caltech