Official name STPSAT-6
Alternative name STPSat-6
Cospar ID 2021-118A
Norad ID 49817
Launch date 2021-12-07
Launch site AFETR
Launch vehicle Atlas-5(551)²
Country/Organization USA
Type application Technology
Operator US Air Force (USAF) STP (Space Test Program)
RCS size LARGE
Decay date ON ORBIT
Period (min) 1436.09
Inclination (deg) 0.06
Perigee (km) 35783
Apogee (km) 35790
Eccentricity 9.78022438629092E-05
Mean motion (revs. per day) 1.00272267058471
Semi-Major axis (km) 42164.635
Raan (deg) 90.7515
Arg of perigee (deg) 274.868
Shape Box + 1 Pan
Mass (kg) 1000
Height (m) 2
Width (m) 1
Depth (m) 1
Span (m^2) 2
Lifetime 8-10 years
Contractors Northrop Grumman Innovation Systems (NGIS) (formerly Orbital ATK)
Equipment SABRS-3, LCRD, CEASE, FalconSEED, RHEME, SENSER, SIRI, UVSC Pathfinder, ?
Propulsion 12 × 22 N REAs
Configuration A-500 bus
Power 2 deployable solar arrays, batteries

STPSat 6 is a planned experimental spacecraft for the Department of Defense's Space Test Program (STP).

The satellite is based on Northrop Grumman Innovation Systems's (NGIS) (formerly Orbital ATK's) high-end modular A-500 bus, which another U.S. government agency bought for a different geosynchronous mission (DARPA's Phoenix program) but transferred to the Space Test Program after deciding it didn?t need it. The satellite will be directly inserted into an orbit slightly above the geostationary orbit.

STPSat-6 will carry nine experiments into a geosynchronous orbit:

  • Space and Atmospheric Burst Reporting System-3 (SABRS-3) by the National Nuclear Security Administration, , which provides nuclear detonation detection and space environment data, and is designed to complement nuclear detonation detectors aboard current GPS spacecraft. SABRS detects, locates, and reports nuclear detonations (NUDETs) in the earth?s atmosphere and in near space in near-real time. The payload augments U.S. operational NUDET detection capabilities, serving as an operational element of the U.S. NUDET Detection System (USNDS).
  • Laser Communications Relay Demonstration (LCRD) by NASA, which was originally planned to be flown as a hosted payload on an SSL built commercial communications satellite. LCRD provides high data rate optical communication services to meet the growing need for higher data rates in space science and exploration. LCRD operationally demonstrates bi-directional uplink and downlink optical communications. The LCRD optical links interface with the spacecraft Ka band links to enable on-board hand-off between RF and Optical for both uplink and downlink.
  • Compact Environmental Anomaly Sensor Experiment III (CEASE) ? Air Force Research Laboratory (AFRL)
  • Falcon Solid-State Energetic Electron Detector (FalconSEED) ? U.S. Air Force Academy
  • Rad-Hard Electronics Memory Experiment (RHEME) ? AFRL
  • Space & Endo-Atmospheric NUDET Surveillance Experiment and Risk-Reduction (SENSER) by NNSA, will test critical technologies in the space environment before production and integration into the next generation of systems to reduce the development risk for future nuclear explosion detection sensors
  • Strontium Iodide Radiation Instrumentation (SIRI) ? Naval Research Lab
  • Ultraviolet Spectro-Coronagraph Pathfinder (UVSC Pathfinder) by NASA and Naval Research Lab, which is to use a new UV coronagraph design concept to make the first remote-sensing measurement of a suprathermal particle distribution in the corona capable of seeding SEP acceleration.
  • one unidentified experiment

Launch of the satellite is planned as the primary payload on the STP-3 launch in 2018, to be competively bid between an ULA Atlas-5 or a SpaceX Falcon-9 v1.2 (Block 5) rocket. In June 2017, am Atlas-5(551)² was selected to launch the STP-3 mission, including an integrated propulsive EELV Secondary Payload Adapter (LDPE 1) holding up to six payloads, in 2019.

Satellite COSPAR Date LS Launch Vehicle Remarks
STPSAT-6 2021-118A 2021-12-07 AFETR Atlas-5(551)² with LDPE 1, Ascent