The STAR-X Observatory

Spacecraft with Exploded View of X-ray Telescope
Spacecraft with Exploded View of X-ray Telescope

XRT Mirror Assembly

Design

  • Lightweight, low-cost optics from single-crystal silicon
  • Wolter-Schwarzschild optical design, focal length 4.0 m, outer diameter 1.2 m
  • Large effective area, large FOV
  • Excellent PSF in entire FOV: 2.5 arcsec HPD on-axis, ≤6 arcsec FOV averaged
  • Mass production using proven processes minimizes cost and schedule

Spacecraft Bus

Design

  • High heritage design (BCP-Small spacecraft w/ FSW reuse >90%)
  • Externally mounted components for easy AI&T
  • High pointing accuracy <15 arcsec (Pitch/Yaw, 3σ)
  • S-band Omni to MGS and NSN-SR
  • On-board transient event detection and alert to ground
  • Rapid response to Targets of Opportunity

XRT Focal Plane Assembly

Design

  • Four Charge-Coupled Device (CCD) chips
  • Large Focal Plane Coverage: 100 mm × 100 mm (16.8 MegaPixels)
  • Back-illuminated CCD chips provide low energy response
  • Straightforward thermal design: TECs and passive cooling maintain focal plane at -70°C
  • Warm contamination control filter

UVT

Ultraviolet Telescope (UVT)
Ultraviolet Telescope (UVT)

Design

  • 33 cm C.A. Ritchey-Chretien telescope for complementary UV imaging
  • 50 mm sealed MCP detector
  • High sensitivity with ≤ 5" HPD PSF averaged across FOV
 

Mission Requirements

Orbit: 5° inclination, 600 km, circular
Transient Event Alert: Within 5 mins of on-board detection, through NSN-SR (90% of the time)
Response to ToO: ≤ 120 mins of receipt (80% of the time)
Slew and Repoint: 120° in less than 9 mins; 0.5° in 26 sec
Astrometric Knowledge: 2.8 arcsec (3σ)
Observing Efficiency: > 73%
Launch Readiness Date: July 2028

 

Instrument Requirements

X-ray Telescope Assembly

Energy Band: 0.2-6 keV
Field of View: 1.0 deg2
Point spread function: 2.5 arcsec half-power diameter on-axis, ≤6 arcsec FOV-averaged
Spectral Resolution (FWHM) (eV): ≤100 (1 keV), ≤150 (3 keV)
Sensitivity in 10 ks (5σ; erg cm-2 s-1): <8 x 10-14 (0.5-2 keV)

UV Telescope Assembly

Energy Band: 165-300 nm
Field of View: 0.8 deg2
Point spread function: ≤ 5.0 arcsec FOV-averaged
Filters: ≥3 (180 nm, 225 nm, and 275 nm)

XRT Requirements

Energy (keV) 1 3
On-axis Effective Area (cm2) ≥1700 ≥280

UVT Requirements

Wavelength (nm) 180 225 275
Effective Areas (cm2) On-axis ≥25 ≥15 ≥25
5σ Sensitivity in 1000s (mag) 22.7 21.8 22.3