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SpaceChina

Shijian-21 and Shijian-25

On-orbit servicing and inspection satellitesIn servicePending verification

Also known as: SJ-21, SJ-25

SpaceCHN
Identification silhouette. Not drawn to scale between entries.
Fact cardConfidence · Source
System
TypeOn-orbit servicing and inspection satellites
Alternative designationsSJ-21, SJ-25
ProliferationOrigin country only
First launch2021Med[1]
Program statusSJ-21 docked with BeiDou-2 G2 and moved it above GEO (January 2022); SJ-21 and SJ-25 maneuvered into extremely close proximity in probable refueling experimentsMed[2]
Mission
MissionRendezvous, docking, debris removal and refueling experimentsMed[3]
Orbit
Orbit regimeGEOMed[1]
Catalogued on orbit2Payloads with current element sets in the public catalog, active or not.High[4]
Active (CelesTrak)2Count in the CelesTrak active satellites list, which estimates operational status.Med[4]
Perigee35,560–35,599 kmActive satellites per CelesTrak, element epoch about 2026-11-08.High[4]
Apogee35,974–36,010 kmActive satellites per CelesTrak, element epoch about 2026-11-08.High[4]
Orbital period1,436–1,436.1 minActive satellites per CelesTrak, element epoch about 2026-11-08.High[4]
Inclination5.39–5.45 °Active satellites per CelesTrak, element epoch about 2026-11-08.High[4]
Catalogued satellites · 2[4]
NameNORADCOSPARPerigee kmApogee kmIncl. °Period minStatus
SHIJIAN-21 (SJ-21)493302021-094A35,56036,0105.451436Active
SHIJIAN-25 (SJ-25)624852025-002A35,59935,9745.391436.1Active

Mean elements at epoch 2026-11-08 or later. Perigee and apogee are computed from mean motion and eccentricity and are approximate. Status follows the CelesTrak active list.

Summary

Chinese GEO servicing satellites; SJ-21 towed a dead BeiDou satellite to a graveyard orbit and SJ-25 conducted probable refueling with SJ-21.

Draft entry. Values come from the cited public sources and are awaiting editor verification.
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Operators
China
Sources
  1. Shi Jian 21 (SJ 21), Gunter's Space Page
    Tier 3 · checked 2026-11-08
  2. Space Threat Fact Sheet (current as of December 2025), U.S. Space Force, Headquarters Space Force Intelligence
    Published/updated 2025-12-01 · Tier 1 · checked 2026-11-08
  3. Shi Jian 25 (SJ 25), Gunter's Space Page
    Tier 3 · checked 2026-11-08
  4. NORAD GP element sets (current data), CelesTrak (data from the U.S. Space Force 18th/19th Space Defense Squadron catalog)
    Published/updated 2026-11-08 · Tier 1 · checked 2026-11-08
Change log
  • 2026-11-08 Entry created from cited open sources
  • 2026-11-08 Orbital elements from CelesTrak GP data (epoch about 2026-11-08): 2 catalogued, 2 active.