# Apollo 9 SIVB

> The Apollo Saturn V SIVB was the third stage of the Saturn V booster.

**Wikidata**: [Q111912944](https://www.wikidata.org/wiki/Q111912944)  
**Source**: https://4ort.xyz/entity/apollo-9-sivb

## Summary
The Apollo 9 SIVB was the third stage of the Saturn V booster used in the Apollo 9 mission. It served as a critical spacecraft component for orbital insertion and trans-lunar injection maneuvers during the mission.

## Key Facts
- Aliases: Apollo 9 Saturn V third stage, 03770, Apollo9SIVB
- COSPAR ID: 1969-018B
- NSSDCA ID: 1969-018B
- Instance of: spacecraft
- Function: Third-stage propulsion system for the Saturn V launch vehicle
- Mission: Apollo 9 (Earth-orbit test flight of Apollo spacecraft systems)

## FAQs
- What is the Apollo 9 SIVB?  
  It was the third stage of the Saturn V booster specifically designed for the Apollo 9 mission, providing thrust for orbital maneuvers.

- What alternative names does the Apollo 9 SIVB have?  
  It is also referred to as Apollo 9 Saturn V third stage, 03770, and Apollo9SIVB.

- What identifiers are associated with the Apollo 9 SIVB?  
  It carries the COSPAR ID 1969-018B and NSSDCA ID 1969-018B for tracking and cataloging purposes.

- How is the Apollo 9 SIVB classified?  
  It is classified as a spacecraft, defined as a vehicle or machine designed to fly in space.

## Why It Matters
The Apollo 9 SIVB was instrumental in validating the Saturn V's third-stage performance during the first complete Apollo spacecraft test in Earth orbit. Its successful operation confirmed the propulsion system's reliability for subsequent lunar missions, directly enabling the Apollo program's goal of human lunar exploration. As a spacecraft component, it demonstrated the critical role of multi-stage rocketry in achieving orbital and translunar trajectories.

## Notable For
- Being the third stage of the Saturn V booster for the Apollo 9 mission
- Providing the thrust required for Apollo 9's Earth-orbit insertion and trans-lunar injection maneuvers
- Carrying the unique identifiers COSPAR ID 1969-018B and NSSDCA ID 1969-018B
- Serving as a spacecraft component in the Apollo program's Earth-orbit test phase

## Body
### Overview
The Apollo 9 SIVB was the third stage of the Saturn V launch vehicle, specifically configured for the Apollo 9 mission. As a spacecraft component, it provided the primary propulsion for orbital maneuvers and simulated trans-lunar injection during the mission. The stage was identified by the COSPAR ID 1969-018B and NSSDCA ID 1969-018B, and was also known by the aliases Apollo 9 Saturn V third stage, 03770, and Apollo9SIVB.

### Classification
The Apollo 9 SIVB is classified as a spacecraft, which encompasses vehicles designed for spaceflight including satellites, probes, and crewed vehicles. This classification aligns with its role as a critical component of the Apollo program's space-based operations.

### Mission Role
During the Apollo 9 mission, the SIVB stage performed two critical burns: the first placed the Apollo 9 command and service module into Earth orbit, while the second simulated the trans-lunar injection maneuver. These operations were essential for testing the spacecraft systems in a space environment before lunar missions.

### Technical Context
As the Saturn V's third stage, the SIVB utilized liquid hydrogen and liquid oxygen propellants to generate the thrust required for orbital and translunar maneuvers. Its design was standardized across Apollo missions but specifically adapted for the Earth-orbit objectives of Apollo 9.

### Program Significance
The Apollo 9 SIVB's successful operation validated the Saturn V's third-stage performance in a crewed mission, directly supporting the Apollo program's progression toward lunar landing. Its Earth-orbit test phase provided critical data for refining spacecraft systems before the Apollo 10 and 11 lunar missions.