NuSTAR Live Tracker
NASA's Nuclear Spectroscopic Telescope Array, launched 13 June 2012 aboard a Pegasus XL rocket air-dropped over the Pacific. The first space telescope ever to focus hard X-rays above 10 keV, opening a whole new window on black holes, supernova remnants and the highest-energy processes in the universe.
NuSTAR Traces Radioactive Titanium in Supernova 1987A
A new NuSTAR image maps the distribution of radioactive titanium-44 in the ejecta of SN 1987A. The asymmetric distribution supports theoretical models where supernova explosions are driven by convective turbulence rather than symmetric shockwaves.
The First to Focus Hard X-rays in Space
NuSTAR opened up an entire waveband to astronomy. Before 2012, no space telescope could focus X-rays above 10 keV, so the hardest X-ray sky was seen only through collimators or coded masks with degree-scale resolution. NuSTAR's 10-metre-long focal length delivers 18-arcsecond imaging up to 79 keV, sharpening our view of black hole accretion, radioactive supernova ejecta, and hot solar corona.
Two Optics, Two Detectors, One 10-metre Mast
NuSTAR carries two identical co-aligned hard X-ray telescopes. Each optic focuses onto its own focal-plane module 10 metres away. A metrology laser tracks micron-scale mast bending so the pointing can be corrected in software.
14 Years of Hard X-ray Science
What NuSTAR Has Actually Seen
Fourteen years of hard X-ray focusing has reshaped what we know about black holes, supernovae, and the highest-energy processes in the universe.
NuSTAR vs Chandra, XMM and Fermi
X-ray astronomy is divided by energy band. NuSTAR is the only mission focusing photons above 10 keV; every other X-ray observatory works below that.
| Telescope | Waveband | Mirror | Orbit | Launched |
|---|---|---|---|---|
| NuSTAR | Hard X-ray (3, 79 keV) | 2 × multilayer, 10 m FL | LEO ~550 km | Jun 2012 |
| Chandra | Soft X-ray (0.1, 10 keV) | 1.2 m Wolter grazing | HEO 14k, 133k km | Jul 1999 |
| XMM-Newton | Soft X-ray (0.1, 12 keV) | 3 co-aligned mirrors | HEO 6k, 100k km | Dec 1999 |
| Fermi (LAT) | Gamma-ray (30 MeV+) | 96 cm² detector | LEO 550 km | Jun 2008 |
Why NuSTAR Sees What Chandra Can't
X-ray telescopes work by reflecting photons off mirrors at very shallow angles. Below 10 keV, the required grazing angle is a few tenths of a degree, achievable with a compact optic. Above 10 keV, the angle drops so far that either the focal length becomes impractically long, or the reflectivity collapses. Chandra and XMM stop around 10 keV for this reason.
The multilayer breakthrough
NuSTAR's optics work up to 79 keV using multilayer coatings, dozens of alternating platinum and silicon carbide layers only atoms thick, deposited on nested mirror shells. Each interface reflects some photons; the whole stack behaves like a Bragg mirror for hard X-rays. The physics was proven on the ground for years; NuSTAR was the first mission to fly it.
The 10-metre mast
Even with multilayers, the focal length has to be 10 metres. Since a 10-metre-long spacecraft is impractical to launch, NuSTAR launched compact and deployed a coiled longeron mast one week after reaching orbit. The mast holds the mirrors 10 metres away from the focal-plane detectors. Slight bending under thermal loads is corrected in software using a metrology laser.
What comes next
ESA's Athena mission targets the 2030s and will focus soft X-rays with much greater area than Chandra. For hard X-rays above 10 keV, NuSTAR remains the only focusing telescope in orbit, and no successor mission is scheduled.
NuSTAR, Frequently Asked
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