NuSTAR (SMEX 11)

Spacecraft n°:

US spacecraft n°:

Launch data: Designation  38358 / 12031A Launch date  13 Jun 2012 - 16:00 UT Launch site  Kwajalein Atoll, L-1011, RW06/24 Launch vehicle  Pegasus-XL Mission  Government: Space Science Astronomy, X-ray telescope LEO Earth orbit: Perigee / Apogee  614 x 633 km Eccentricity  1,36E-03 Inclination  6.02 deg Period  97.19 min

NuSTAR has a 10-m (30') mast that deploys after launch to separate the optics modules (right) from the detectors in the focal plane (left).

Spacecraft data: Prime manufacturer  Orbital Sciences Corporation (OSC) Platform  LEOStar-2 Operator  NASA Mass at launch  360 kg Dry Mass   kg Basic shape   Dimension (m)   Equipment  2 co-aligned hard X-ray telescopes Solar array  1 Deployable solar array Stabilization   Propulsion   DC power   Design lifetime  2 yrs

NuSTAR observatory at Orbital Sciences Corporation, January 2012. Credit: JPL

Description:

• NuSTAR is a small X-ray telescope, considered the first step in an ambitious low-cost mission to study supermassive black holes believed to be lurking at the cores of galaxies like Earth's Milky Way and to probe the creation of heavy elements in the cataclysmic death throes of massive stars.
• NASA's NuStar satellite is the first X-ray astronomy satellite with optics able to focus `hard' X-rays (about 10-100 keV in general, 6-80 keV in this particular case); an extendable mast carries two optics modules, each 0.38m in diameter and focussing images onto 64 x 64 pixel CdZnTe detector arrays, with 40 arcsecond spatial resolution. The spacecraft will be particularly useful for studying obscured black holes (ones whose other radiation is absorbed by surrounding material) and the distribution of chemical elements in supernova remnants.
• Its primary scientific goals are to conduct a deep survey for black holes a billion times more massive than our sun, understand how particles are accelerated to within a fraction of a percent of the speed of light in active galaxies, and understand how the elements are created in the explosions of massive stars by imaging the remains, which are called supernova remnants.
• NuSTAR is a pointed telescope, which will be launched by a Pegasus-XL into a low-Earth, equatorial orbit from Kwajalein. The planned mission will last for three years, although less than half that time is required to meet the core science goals. NuSTAR will ordinarily follow a preprogrammed observation plan, but will have the capability of responding to transient opportunities within a day of notification.
• The NuSTAR instrument consists of an array of two co-aligned hard X-ray telescopes. The grazing incidence mirrors focus onto two shielded solid-state pixel detectors, separated by a mast that extends the focal length to 10 m after launch. The optics utilize thin glass shells coated with depth-graded multi-layers to extend the bandpass and FOV over that achievable with standard metal surfaces. Cadmium Zinc Telluride (CdZnTe) detectors provide excellent spectral resolution and high quantum efficiency without requiring cryogenic operation. All major elements of the instrument have flight heritage (space flight and HEFT balloon experiment).
• The long focal length requires the use of a 10 m extendable mast. The design chosen is produced by Able Engineering, and is a straightforward reduction of the 60 m mast successfully deployed for the SRTM program. A laser metrology system monitors the mast alignment.
• During a two-year primary mission phase, NuSTAR will map selected regions of the sky in order to:
  • take a census of collapsed stars and black holes of different sizes by surveying regions surrounding the center of own Milky Way Galaxy and performing deep observations of the extragalactic sky;
  • map recently-synthesized material in young supernova remnants to understand how stars explode and how elements are created; and
  • understand what powers relativistic jets of particles from the most extreme active galaxies hosting supermassive black holes.
• First focusing telescopes to image the sky in the high energy X-ray (6 - 79 keV) region of the electromagnetic spectrum.

Mission details:

• The launch has been delated from 15 August 2011, 3 February 2012, 14 March, 16 March and 01 May 2012.
• The L-1011 airplane took off from Kwajalein at 1500 UTC and dropped the Pegasus at 1600:37 UTC over 167.70E 6.74N. The vehicle reached orbit at 1610 UTC, and NuStar separated from the third stage at 1613 UTC in a 627 x 633 km x 6.0 deg orbit. The equatorial orbit avoids the high particle background seen by polar orbit satellites.
• The 360 kg satellite is a small telescope, but the hard X-ray band is relatively little-explored. The major X-ray observatories - Chandra and XMM-Newton - work in the 0.5-10 keV `normal' X-ray range, and the gamma-ray observatories start paying attention around 100 keV and upwards.
• The NuSTAR hard X-ray observatory extended its ten-meter mast on Jun 21, 2012 from 1743 to 1809 UTC, a critical mission event which places its twin optics modules at the correct distance from the focal plane detectors.
  It was reported on Jun 28 that the first light observation of Cyg X-1 was successful and shows a good image.