ANNA Satellite Bus
Data current as of 2026-07-21.
The ANNA bus accounts for 3 cataloged objects, of which 3 are in orbit and 0 are active. Most are built by APL. The largest operator on this bus is NASA. The first launched in 1965, the most recent in 1975.
3
In orbit
0
Active
3
Total launched
0
Reentered
ANNA launched per year
Still in orbit Click a year to list its satellites.
Typical specifications
Most common values across cataloged ANNA satellites.
| Manufacturer | APL |
|---|---|
| Purpose | Research |
| Launch mass | 176 kg |
| Dry mass | 176 kg |
| Length | 1.1 m |
| Diameter | 1.2 m |
| Span | 15 m |
| Shape | Oct Cyl + Dome + Ant |
| Power | Solar cells, batteries |
| Propulsion | ? |
| Equipment | Optical Beacon System, Radio Doppler System, Radio Range/Rate System, C-Band Radar Transponder, NASA Minitrack System, Precipitating Electron Detector, Magnetometer, Laser Tracking Reflector, TR-27 SECOR transponder (#A), TR-30A/S SECOR transponder (#B) |
| Typical orbit | 101 min period, 59° inclination |
Top operators
NASA 2 WFC 1
Top countries
US 3
ANNA satellites
Track any of them live in KeepTrack.
| Name | NORAD | COSPAR | Owner | Launched | Orbit | Status | Track |
|---|---|---|---|---|---|---|---|
| GEOS 3 Geos 3 | 07734 | 1975-027A | WFC | Apr 9, 1975 | 101 min, 115.0° | Inactive | ◉ |
| EXPLORER 36 (GEOS 2) Geos 2 | 03093 | 1968-002A | GSFC | Jan 11, 1968 | 112 min, 105.8° | Inactive | ◉ |
| EXPLORER 29 (GEOS 1) Explorer 29 | 01726 | 1965-089A | GSFC | Nov 6, 1965 | 120 min, 59.4° | Inactive | ◉ |
Frequently asked questions
How many ANNA satellites are there?
The catalog lists 3 objects built on the ANNA bus. 3 are in orbit and 0 have reentered.
How many ANNA satellites are in orbit?
3 ANNA objects are currently in orbit, of which 0 carry an active status.
Who builds the ANNA bus?
The ANNA bus is most commonly built by APL.
When did the first ANNA satellite launch?
The first cataloged ANNA satellite launched in 1965, and the most recent in 1975.