| TechSat-21 | |
| Mission Type: | Technology |
| Operator: | AFRL, STP, NASA |
| Manufacturer: | MicroSat Systems |
| Launch Mass: | 181kg (399lb) |
| Launch Date: | Not launched |
| Launch Rocket: | Atlas V 401 |
| Launch Site: | Cape Canaveral SLC-41 |
| Orbit Epoch: | Planned |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Low Earth |
| Orbit Periapsis: | 560km (350miles) |
| Orbit Apoapsis: | 560km (350miles) |
| Orbit Inclination: | 35.4& degrees |
| Apsis: | gee |
TechSat-21 (Technology Satellite of the 21st Century) was a small spacecraft developed by the U.S. Air Force Research Laboratory's Space Vehicles Directorate to test technology for formation flight of spacecraft which can rapidly change formation based on mission requirements.[1] The project was canceled in 2003 due to numerous cost overruns.[2]