# SPARTAN 101

> American X-ray astronomy spacecraft flown during STS-51-G

**Wikidata**: [Q113149082](https://www.wikidata.org/wiki/Q113149082)  
**Source**: https://4ort.xyz/entity/spartan-101

## Summary
SPARTAN 101 is an American X-ray astronomy spacecraft that was carried into orbit and deployed from the Space Shuttle Discovery during NASA’s STS-51-G mission. It is the first flight unit of NASA’s SPARTAN series of free-flying, Shuttle-launched science platforms.

## Key Facts
- Launch date: 17 June 1985 (reference: NSSDC Master Catalog)
- COSPAR ID: 1985-048E
- NSSDCA ID: 1985-048E
- Part of: SPARTAN program (United States)
- Instance of: spacecraft
- Also known as: SPARTAN-A, SPARTAN101, SPARTAN 101-F1, SPTN-101, SPARTAN 1
- Launch site: Cape Canaveral Space Launch Complex 17
- Mission: STS-51-G (Space Shuttle Discovery)
- Primary discipline: X-ray astronomy

## FAQs
### Q: What was SPARTAN 101 used for?
A: SPARTAN 101 served as a short-duration, free-flying X-ray observatory. After release from the Shuttle, it pointed at cosmic X-ray sources and returned data until it was retrieved two days later.

### Q: How did SPARTAN 101 get into space?
A: It was carried to orbit inside Space Shuttle Discovery on mission STS-51-G and spring-ejected from the payload bay; after its autonomous observing sequence, astronauts used the Shuttle’s robot arm to recapture it.

### Q: Is SPARTAN 101 still in orbit?
A: No. The spacecraft was returned to Earth aboard Discovery at the end of STS-51-G, so it never remained in space as a long-term satellite.

## Why It Matters
SPARTAN 101 demonstrated that relatively small, inexpensive platforms could be released from the Shuttle, operate autonomously while conducting high-energy astrophysics, and then be returned for reuse. This “fly-away, fly-back” concept reduced mission cost and risk compared with full-scale free-flyers, validated the SPARTAN modular design, and gave U.S. scientists rapid access to space after the 1984 SPARTAN-1 failure. The flight returned high-quality X-ray data and proved the Shuttle could serve as a flexible launch and recovery vehicle for small payloads, influencing later SPARTAN missions and other Shuttle-based science carriers.

## Notable For
- First successful flight of the NASA SPARTAN platform family
- First Shuttle-deployed payload to be retrieved after free-flight operations
- Returned intact, enabling post-mission calibration and hardware reuse
- Provided early low-cost access to X-ray astronomy from space in the mid-1980s

## Body
### Background
NASA’s Goddard Space Flight Center created the SPARTAN series to give scientists low-cost, reusable spacecraft that could be deployed and retrieved by the Space Shuttle. SPARTAN 101—internally designated SPARTAN 101-F1—was the first operational unit, launched on STS-51-G.

### Mission Profile
On 17 June 1985 Discovery lifted off from Kennedy Space Center. After reaching orbit, the crew spring-ejected SPARTAN 101 from its support structure in the payload bay. The spacecraft spent about 45 hours flying free, pointing at X-ray targets with its attitude-control system. Astronauts then performed a rendezvous, grappled the craft with the Remote Manipulator System, and berthed it for return to Earth when Discovery landed on 24 June 1985.

### Technical Notes
- Launch mass: not specified in source
- Attitude control: three-axis stabilized
- Data recovery: onboard tape recorder; real-time links via Shuttle during checkout periods
- Re-use: hardware returned for post-flight inspection and refurbishment

## References

1. Jonathan's Space Report