# TDRS-B

> communications satellite lost during launch of STS-51-L

**Wikidata**: [Q7669874](https://www.wikidata.org/wiki/Q7669874)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/TDRS-B)  
**Source**: https://4ort.xyz/entity/tdrs-b

## Summary
TDRS-B was a Tracking and Data Relay Satellite launched by NASA on January 28, 1986, aboard the Space Shuttle mission STS-51-L. The satellite was lost when the Space Shuttle Challenger disintegrated shortly after liftoff, resulting in the complete destruction of the spacecraft and its payload.

## Key Facts
- **Launch Date:** January 28, 1986 at 16:38 UTC
- **Launch Vehicle:** Space Shuttle Challenger (mission STS-51-L)
- **Launch Site:** Kennedy Space Center Launch Complex 39B
- **Operator:** National Aeronautics and Space Administration (NASA)
- **Manufacturer:** TRW Inc.
- **Mass:** 2,200 kilograms (launch weight)
- **Dimensions:** 12.9 meters wide, 17.4 meters long
- **Power Output:** 1,700 watts nominal
- **Upper Stage:** Inertial Upper Stage (IUS-3)
- **Fate:** Destroyed during launch due to the Challenger disaster at 16:39:13 UTC

## FAQs
### Q: What happened to TDRS-B?
A: TDRS-B was destroyed during the launch of Space Shuttle mission STS-51-L on January 28, 1986, when the Challenger shuttle disintegrated 73 seconds after liftoff. The entire crew and payload, including TDRS-B, were lost in the accident.

### Q: What was TDRS-B designed to do?
A: TDRS-B was part of the Tracking and Data Relay Satellite System (TDRSS), which provides communication relay services between Earth and orbiting spacecraft. It would have enabled continuous data transmission between ground stations and satellites or shuttles in low Earth orbit.

### Q: Was TDRS-B ever replaced?
A: Yes, following the loss of TDRS-B, NASA launched TDRS-C (later renamed TDRS-1) in September 1988 as the first operational satellite in the system. Subsequent missions continued the deployment of the TDRSS constellation.

## Why It Matters
TDRS-B represented a critical component in NASA's effort to establish near-continuous communication coverage with its orbiting assets through the Tracking and Data Relay Satellite System (TDRSS). Its loss underscored the vulnerability of complex space systems and highlighted the risks associated with human spaceflight. The failure had lasting implications for both satellite deployment strategies and safety protocols within NASA, contributing to broader changes in how payloads are managed during crewed launches.

## Notable For
- One of only two TDRS satellites lost during launch (the other being TDRS-D, damaged but repaired)
- First major payload casualty of the Space Shuttle Challenger disaster
- Demonstrated the high-stakes nature of integrating large communication satellites into human-rated launch vehicles
- Highlighted the importance of redundancy in space-based communication infrastructure
- Symbolic representation of the technological ambitions and tragic setbacks of the early Space Shuttle era

## Body
### Mission Overview
TDRS-B was the second satellite in the Tracking and Data Relay Satellite series, intended for use in NASA’s Tracking and Data Relay Satellite System (TDRSS). Designed to provide continuous communication relay between Earth and orbiting spacecraft, it was scheduled to operate in geostationary orbit after deployment via the Space Shuttle's Inertial Upper Stage (IUS).

### Technical Specifications
The satellite weighed approximately 2,200 kg at launch and featured a solar array generating up to 1,700 watts of power. With dimensions of 12.9 meters in width and 17.4 meters in length, it was equipped with S-band and Ku-band transponders to support multiple simultaneous data links.

### Launch Details
Launched on January 28, 1986, at 16:38 UTC aboard Space Shuttle Challenger mission STS-51-L from Kennedy Space Center’s Launch Complex 39B, TDRS-B was mounted in the shuttle’s payload bay along with the Inertial Upper Stage that would have boosted it into geosynchronous transfer orbit.

### Loss of Vehicle
At 16:39:13 UTC—just over one minute after liftoff—the Space Shuttle Challenger suffered catastrophic structural failure caused by O-ring seal failure in its right solid rocket booster. The vehicle broke apart, killing all seven crew members and destroying the entire payload, including TDRS-B.

### Aftermath and Legacy
Following the disaster, NASA grounded the Space Shuttle fleet for nearly three years while conducting investigations and implementing design fixes. Although TDRS-B could not be recovered, the program proceeded with the successful launch of TDRS-C in 1988, restoring progress toward full TDRSS capability. The incident remains a defining moment in aerospace history, emphasizing risk management and engineering rigor in human spaceflight operations.

## References

1. Jonathan's Space Report
2. [Source](https://space.skyrocket.de/doc_stage/ius.htm)
3. [Source](https://www.nasa.gov/directorates/heo/scan/services/networks/tdrs_characteristics)