77KS Satellite Bus
Data current as of 2026-07-20.
The 77KS bus accounts for 10 cataloged objects, of which 1 are in orbit and 1 are active. 9 have reentered. Most are built by ZIKH. The largest operator on this bus is ZIKH. The first launched in 1977, the most recent in 1998.
1
In orbit
1
Active
10
Total launched
9
Reentered
77KS launched per year
Still in orbit Since reentered Click a year to list its satellites.
Typical specifications
Most common values across cataloged 77KS satellites.
| Manufacturer | ZIKH |
|---|---|
| Purpose | Space station |
| Launch mass | 14750 kg |
| Dry mass | 14000 kg |
| Length | 13 m |
| Diameter | 4.2 m |
| Span | 13 m |
| Shape | Cyl + 2 Pan |
| Power | 2 deployable fixed solar arrays, batteries |
| Propulsion | 2 main engines (417 kgf each, turbopump-fed, regeneratively-cooled) — permanently disabled after Zvezda docking. 24 large steering jets (40 kgf each). 12 small steering jets (1.3 kgf each). 16 external fuel tanks (total capacity 6.1 tonnes propellant). 16 pressurant tanks. |
| Design life | 15 years design life. Still operational as of March 2026, exceeding 27 years on orbit. FGB propulsion system life extended to 2028 via comprehensive test campaign. |
| Equipment | see above |
| Typical orbit | 93 min period, 52° inclination |
Top operators
ZIKH 4 NPOE 3 RKKE 2 NASA 1
Top countries
SU 7 RU 2 CIS 1
77KS satellites
Track any of them live in KeepTrack.
| Name | NORAD | COSPAR | Owner | Launched | Orbit | Status | Track |
|---|---|---|---|---|---|---|---|
| ISS (ZARYA) Zarya (FGB) | 25544 | 1998-067A | NASA | Nov 20, 1998 | 93 min, 51.6° | Active | ◉ |
| PRIRODA Priroda | 23848 | 1996-023A | RKKE | Apr 23, 1996 | 91 min, 51.6° | Reentered | ◉ |
| SPEKTR Spektr | 23579 | 1995-024A | RKKE | May 20, 1995 | 91 min, 51.6° | Reentered | ◉ |
| KRISTALL Kristall | 20635 | 1990-048A | NPOE | May 31, 1990 | 91 min, 51.6° | Reentered | ◉ |
| KVANT 2 Kvant-2 | 20335 | 1989-093A | NPOE | Nov 26, 1989 | 91 min, 51.6° | Reentered | ◉ |
| KVANT 1 SERVICE POD FSB | 17851 | 1987-030C | NPOE | Mar 31, 1987 | 119 min, 101.9° | Reentered | ◉ |
| COSMOS 1686 Kosmos-1686 | 16095 | 1985-086A | ZIKH | Sep 27, 1985 | 88 min, 51.6° | Reentered | ◉ |
| COSMOS 1443 Kosmos-1443 | 13868 | 1983-013A | ZIKH | Mar 2, 1983 | 91 min, 51.6° | Reentered | ◉ |
| COSMOS 1267 Kosmos-1267 | 12419 | 1981-039A | ZIKH | Apr 25, 1981 | 91 min, 51.6° | Reentered | ◉ |
| COSMOS 929 Kosmos-929 | 10146 | 1977-066A | ZIKH | Jul 17, 1977 | 93 min, 51.6° | Reentered | ◉ |
Frequently asked questions
How many 77KS satellites are there?
The catalog lists 10 objects built on the 77KS bus. 1 are in orbit and 9 have reentered.
How many 77KS satellites are in orbit?
1 77KS objects are currently in orbit, of which 1 carry an active status.
Who builds the 77KS bus?
The 77KS bus is most commonly built by ZIKH.
When did the first 77KS satellite launch?
The first cataloged 77KS satellite launched in 1977, and the most recent in 1998.