HOTSAT 1 [SSTL]
Official name HOTSAT-1
Alternative name HOTSAT 1
Cospar ID 2023-084Y
Norad ID 56954
Launch date 2023-06-12
Launch site AFWTR
Launch vehicle Falcon-9 v1.2 (Block 5)
Country/Organization UK
Type application Earth observation
Operator Satellite Vu
RCS size MEDIUM
Decay date ON ORBIT
Period (min) 94.93
Inclination (deg) 97.54
Perigee (km) 507
Apogee (km) 524
Eccentricity 0.0164888457807953
Mean motion (revs. per day) 15.169071947751
Semi-Major axis (km) 6893.635
Raan (deg) 241.7405
Arg of perigee (deg) 168.4993
Shape Box + Cone + 1 Pan
Mass (kg) 130
Height (m) 1
Width (m) 0.5
Depth (m) 0.5
Span (m^2) 1
Lifetime 5 years (design), 6 months (#1 reached)
Contractors SSTL
Propulsion None
Configuration SSTL-42
Power Solar cells, batteries

HOTSAT 1 is a pathfinder mission built by SSTL for Satellite Vu, flying a low-cost high resolution mid-wave infrared (MWIR) detector. It is a pathfinder for Satellite Vu's seven satellite constellation.

HOTSAT 1 is based on the DarkCarb version of the SSTL Carbonite platform and makes use of a 0.32 m diameter telescope and a Mercury Cadmium Telluride (MCT) cooled detector. One of the main benefits of this design is the ability to image throughout both the day and the night with no sensitivity to lighting conditions. The imager has a ground resolution of 3.5 m and a swath width of 4 km. As the imaging capability is not dependent on illumination conditions, non-SSO orbits can also be considered.

Applications for the DarkCarb satellites are:

  • Change detection and human activity
  • Pattern of life assessments
  • Humanitarian and disaster management
  • Global high resolution situational awareness
  • National security and defence
  • Infrastructure and asset monitoring
  • Urban heat mapping

DarkCarb imagery provides the capability to differentiate between objects and surfaces of different temperature and emissivity, providing complementary information to traditional optical imagery and the ability to extend imaging opportunities into night time.

DarkCarb?s video capability allows for change detection in a single pass. In addition, as the imager can detect temperature differences it should be possible to derive information on recent activity in a scene, such as recently used or moved vehicles, which is not normally discernible in Visible-NIR imagery. DarkCarb also has the potential to assist with disaster support activities; wildfires, volcanic eruptions and flooding for example.

Launch took place in June 2023. The satellite operated only 6 months until the imager failed in December 2023.

Satellite COSPAR Date LS Launch Vehicle Remarks
HOTSAT-1 2023-084Y 2023-06-12 AFWTR Falcon-9 v1.2 (Block 5) with W-Series 1, Skykraft Deployer 3, Skykraft 3A, ..., 3D, ICEYE X23, X25, X26, X30, GHOSt 3, Grégoire, Runner 1, Tomorrow R2, QPS-SAR 6, ÑuSat 40, ..., 43, Aces 1, ..., 4, HOTSAT 1, AFR, DROID.001, MuSat 1, ION-SCV 011, Outpost Mission 1, EPICHyper 2, Kelpie 2, Spei Satelles, ELO 4, MRC-100, Unicorn 2I, SATLLA 2I, URESAT 1, Istanbul, ROM 2, Orbiter SN3, Otter Pup, MDQSAT 1C, 1D, Pleiades-Squared, GEI-SAT Precursor, XVI, AII-Delta, Ayris 1, 2, EIVE, FOREST 2, Lemur-2 167, 168, MISR-A 1, MISR-B 2, Tiger 4, FOSSASat FEROX 1, ..., 4, SpaceBEE 168, ..., 179