Nasa’s Nustar X-ray telescope rides to orbit

Nasa has launched its latest orbiting X-ray observatory.

The Nuclear Spectroscopic Telescope Array (Nustar) was sent into space on a Pegasus rocket operated out of the Kwajalein Atol in the central Pacific.Nustar will study high-energy X-rays coming from exotic sources such as black holes, exploded stars and the hot gas in galaxy clusters.

The observatory will capture its target X-rays using a novel optics system held on the end of a 10m-long extension.

“Nustar will open up a whole new window on the Universe by being the very first telescope to focus high-energy X-rays,” explained Fiona Harrison, Nustar’s principal investigator from the California Institute of Technology in Pasadena, California.

“As such it will make images that are 10 times crisper and 100 times more sensitive than any telescope that has operated in this region of the spectrum.”

Nustar will be sensitive to X-ray photons with energies in the range of six to 79 kiloelectron volts (keV). This is beyond the vision of the two large-class observatories currently in orbit – Nasa’s Chandra telescope and the European Space Agency’s (Esa) XMM-Newton facility.

Nustar’s breakthrough is the new technology that has gone into its nested shells of highly reflective grazing mirrors, and the detectors it will be using in its camera system. The long mast that gives Nustar its 10m focal length has never been deployed on a space telescope before but borrows heavily from the extendable radar mechanisms flown on shuttle missions in the 1990s.

Nustar’s total mission budget is $170m (£110m), which includes the cost of development, the launch vehicle and two years of in-orbit operations.

Nasa could extend the mission in 2014 if it feels the telescope is delivering on its science goals. These include generating sky maps of high-energy X-ray sources. At the moment, such maps are very coarse. It is hoped Nustar will resolve many more objects than has previously been possible.

Nustar will also study the region in the immediate vicinity of black holes, where the immense gravitational attraction of these objects is shredding and accelerating the gas and dust that has got too close.

“By studying atoms in the X-ray band as they circle around the black hole, before they disappear into it, we can actually detect the effects of this strong gravity; and by teaming up with other telescopes such as Chandra and XMM-Newton, we can tell things for example like how fast the black hole is spinning,” said Prof Harrison.

In addition, Nustar will investigate the material recently shed by supernovas to help get a better understanding of how stars explode and how they synthesize heavy chemical elements in the process.

Nustar will even turn its gaze on our Sun, to probe the processes driving the extraordinary million-degree temperatures in its outer atmosphere, or corona.

“One of the dominant theories explaining it is nanoflares, but no telescope prior to Nustar has had the sensitivity to see whether nanoflares actually exist,” said Dan Stern, Nustar project scientist.

“Within a few hours of observations, Nustar will answer this long-standing question that solar physicists have been scratching their heads about for years.”

Nustar went into space on the air-launched Pegasus XL rocket.

This vehicle was carried to a height of about 41,000ft (12.5km) under the belly of a L-1011 Stargazer aircraft.

The Pegasus was then dropped, igniting its motor to take the telescope payload the rest of the way into space.

Nustar’s ascent to the planned 600km-high, equatorial orbit took about 800 seconds.

The telescope’s first task was to open solar array panels to charge its battery. It will be another week before the mast is extended.

“After the mast is deployed, the optics and the detector are at the right separation to make a high-resolution X-ray image, so we can start instrument calibration which lasts approximately three weeks,” said Yunjin Kim, the project manager for the mission at Nasa’s Jet Propulsion Laboratory also in Pasadena.

“After instrument calibration is completed, Nustar is ready to listen to what the X-ray Universe has to tell us.”

By Jonathan Amos Science correspondent, BBC News