The Nuclear Spectroscopic Timing Array, NuStar, is now in orbit. On June 13th, the satellite left Earh on a Pegasus XL rocket launched from a Lockeed L-101 close to the Marshall Islands. The trajectories of the three stages of the rocket were nominal, and the satellite has immediately deployed its solar panels and started communicating with the control rooms.
After some hitches with the attitude control system on June 14th, immediately solved, the satellite has been behaving as expected with the alignment operations using star trackers.
Today, it will deploy its 10m mast to take the focusing optics at the right focal distance, and in about 20 days from now it will be ready to do science.
Check the news on Fiona Harrison's blog.
EDIT: The mast was deployed successfully. Great news (midnight June 21st)!
What's so exciting about it?
As I wrote in a former post, NuStar is the first X-ray satellite that will focus hard X-rays (3 - 80 keV) and obtain images with ~25" resolution. It will be a natural complement of XMM-Newton, an ESA satellite with a slightly better resolution, but in the soft X-rays (0.3-12 keV).
This satellite has nice timing ( 0.1ms) and spectral (0.5keV@10keV, 1keV@60keV) resolution, and will be an extraordinary tool to study, among other things, accreting black holes and neutron stars.
The soft spectra of these objects have in fact delivered a lot of information on their structure and geometry, but often degeneracies arise when fitting them with concurring models. NuSTAR will solve most of these degeneracies: for example, it will be able to tell if some ultraluminous X-ray sources are intermediate mass black holes or unusually bright stellar-mass black holes; it will detect line emission from supernova remnants, to investigate their composition; it will be able to see accreting objects that, because of high absorption from the surrounding and interstellar medium, are too faint to be studied with with soft satellites, allowing us to map the presence of black holes in our galaxy and in others.