Small, cheap black-hole hunter could be new NASA model

You don't have to be big to hunt black holes. NASA's telescope NuSTAR, which was due to take off from an island in the South Pacific on 13 June, is small enough to fit beneath the belly of an aircraft, even including its launch rocket. Once in orbit, it will unfold to the length of a school bus.

The Nuclear Spectroscopic Telescope Array will be the first telescope to bring high-energy X-rays into focus, letting astronomers map and study the extreme physics around black holes and the explosions of massive stars. Its images of these objects will be 10 times crisper and 100 times more sensitive than those of previous telescopes.

To make such sharp images, the telescope needs to focus X-rays with energies of up to 100 kiloelectronvolts – 10 times as energetic as those sought by previous X-ray telescopes – onto a small area. Visible light telescopes can manage this with a focusing lens relatively close to the eyepiece. But because the X-rays are so energetic, NuSTAR's camera needs to be 10 metres away from the focusing lens.

Ingenious model

NuSTAR is on a tight budget: the whole mission should cost only $170 million. As the team could not afford to launch a 10-metre-long telescope, NuSTAR got scrunched up.

"It's no ordinary-looking telescope," says NuSTAR's principal investigator, Fiona Harrison of the California Institute of Technology in Pasadena. Its "lens" is made up of 133 nested shells of fingernail-thin glass. At launch, the cameras will sit right next to the lenses. A week after it settles into orbit, NuSTAR will push the lenses away from the camera on a thin scaffold.

Harrison, who conceived of NuSTAR in the 1990s, thinks the cheap, ingenious scope could be a new model for budget-bedevilled NASA. "It shows you can make huge advances with a relatively small mission," she says.