Demonstration and Science Experiments (DSX).jpg
Artist rendering of the Air Force Research Laboratory Demonstration and Science Experiments (DSX) spacecraft on-orbit with its 80-meter and 16-meter antenna booms extended.
NamesDemonstration and Science Experiments
Deployable Structures Experiment
Mission typeTechnology demonstration
OperatorAir Force Research Laboratory
COSPAR ID2019-036F Edit this at Wikidata
SATCAT no.44344
Mission duration1 year (planned)
1 year, 11 months and 6 days (achieved)
Spacecraft properties
BusESPA ring + 2 SN-200
ManufacturerSierra Nevada Corporation
(formerly MicroSat Systems)
Start of mission
Launch date25 June 2019, 06:30:00 UTC
RocketFalcon Heavy (No. 003)
Launch siteKennedy Space Center, LC-39A
End of mission
Deactivated31 May 2021
Orbital parameters
Reference systemGeocentric orbit[1]
RegimeMedium Earth orbit
Perigee altitude5,988 km (3,721 mi)
Apogee altitude12,051 km (7,488 mi)
Period316.9 minutes
Wave Particle Interaction Experiment (WPIx)
Space Weather Experiment (SPx)
Space Environmental Effects Experiment (SFx)
Adaptive Controls Experiment (ACE)

Demonstration and Science Experiments (DSX) was a small spacecraft developed by the U.S. Air Force Research Laboratory's Space Vehicles Directorate to perform experiments to study the radiation environment in medium Earth orbit.[2][3]


The Air Force Research Laboratory (AFRL) is responsible for the development and execution of the DSX (originally Deployable Structures Experiment), now Demonstration & Science Experiments, also known as Space Science Technology Experiment (SSTE-4), a suite of four science payloads integrated onto a Evolved Expendable Launch Vehicle (EELV) EELV Secondary Payload Adapter (ESPA) ring based three axis stabilized satellite bus nominally slated for launch into a 6000 × 12000 km, 30° inclination, Medium Earth Orbit (MEO) in the 2019 timeframe with one year required and three year desired operational capability.[4]

Unlike the traditional ESPA approach, in DSX the experiments and host spacecraft stay attached and do not deploy. After the primary satellite in the EELV is deployed, the DSX ESPA separates from the EELV 2nd stage booster to become a free-flyer spacecraft. To address the space access aspect of the rapid-response problem, DSX will utilize an EELV Secondary Payload Adapter (ESPA) capability as a platform for highly-capable small and medium free-flying satellites (or ESPASats) that have plentiful and relatively inexpensive launch opportunities on EELV as secondary payloads.[4]

One deployable boom measured 80 meters and a second measured 16 meters, making DSX one of the largest deployable structures built to operate on orbit.[2]


DSX conducted four experiments:


AFRL kept the satellite in operation for nearly two years, rather than the one year planned, using it to conduct more than 1,300 experiments.[5][2]

The DSX mission was successfully completed on 31 May 2021. The spacecraft was passivated rather than deorbited due to its high orbit.[2]


  1. ^ Peat, Chris (14 July 2021). "DSX". Heavens Above. Retrieved 19 July 2021.
  2. ^ a b c d Erwin, Sandra (19 July 2021). "Air Force satellite completes two-year experiment to study the medium Earth orbit environment". SpaceNews. Retrieved 19 July 2021.
  3. ^ "Sierra Nevada Science Missions". Sierra Nevada Corporation. Archived from the original on 14 February 2015. Retrieved 14 February 2015.
  4. ^ a b "Display: DSX 2019-036F". NASA. 27 April 2021. Retrieved 20 July 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  5. ^ "AFRL conducts 1,300 experiments on record-breaking satellite". AFRL. 19 July 2021. Retrieved 20 July 2021. Public Domain This article incorporates text from this source, which is in the public domain.