# Atlas V 551

> United Launch Alliance launch vehicle

**Wikidata**: [Q16352007](https://www.wikidata.org/wiki/Q16352007)  
**Source**: https://4ort.xyz/entity/atlas-v-551

## Summary
Atlas V 551 is a variant of the Atlas V rocket developed by United Launch Alliance (ULA), designed for medium to heavy payload launches. It is part of the Atlas V family, which is an American expendable launch system used for deploying satellites and other spacecraft into orbit.

## Key Facts
- Part of the Atlas V rocket family, developed by United Launch Alliance
- Used for medium to heavy payload launches, including satellites and probes
- Notable payloads include MUOS satellites, STPSat-6, and New Horizons
- Features a 5-meter payload fairing, five solid rocket boosters, and a single-engine Centaur upper stage
- Launched from Cape Canaveral Space Force Station and Vandenberg Space Force Base
- Supports geostationary and low Earth orbit missions
- Retired from active service in favor of newer Atlas V configurations

## FAQs
### Q: What type of missions does the Atlas V 551 support?
A: The Atlas V 551 supports medium to heavy payload launches, including geostationary and low Earth orbit missions, primarily for military and scientific satellites.

### Q: What are some notable payloads launched by the Atlas V 551?
A: Notable payloads include the MUOS satellites (MUOS 1, MUOS 2, MUOS 3, MUOS 4, MUOS 5), STPSat-6, and the New Horizons probe.

### Q: Where is the Atlas V 551 launched from?
A: The Atlas V 551 is launched from Cape Canaveral Space Force Station and Vandenberg Space Force Base in the United States.

### Q: What distinguishes the Atlas V 551 from other Atlas V variants?
A: The Atlas V 551 is characterized by its 5-meter payload fairing, five solid rocket boosters, and a single-engine Centaur upper stage, making it suitable for heavier payloads.

### Q: Is the Atlas V 551 still in use?
A: The Atlas V 551 has been retired from active service, with newer configurations of the Atlas V now in use for current missions.

## Why It Matters
The Atlas V 551 played a crucial role in deploying critical military and scientific satellites, including the MUOS series for the U.S. Navy and the New Horizons probe for NASA. Its ability to handle heavy payloads made it a reliable choice for geostationary and low Earth orbit missions. The retirement of the Atlas V 551 marks the transition to more advanced configurations of the Atlas V family, ensuring continued support for future space missions.

## Notable For
- Successfully launched the MUOS satellites, providing secure communications for the U.S. Navy
- Deployed the New Horizons probe, which conducted the first close flyby of Pluto and the Kuiper Belt object Arrokoth
- Supported the STPSat-6 mission for the U.S. Space Force, demonstrating advanced space technologies
- Launched military communications satellites like USA-288, USA-292, and USA-298
- Retired in favor of newer Atlas V configurations, reflecting advancements in launch vehicle technology

## Body
### Overview
The Atlas V 551 is a variant of the Atlas V rocket, part of the Atlas V family developed by United Launch Alliance. It is designed for medium to heavy payload launches, including satellites and probes.

### Configuration
The Atlas V 551 features a 5-meter payload fairing, five solid rocket boosters, and a single-engine Centaur upper stage. This configuration allows it to support geostationary and low Earth orbit missions.

### Notable Payloads
The Atlas V 551 has launched several significant payloads, including the MUOS satellites (MUOS 1, MUOS 2, MUOS 3, MUOS 4, MUOS 5), STPSat-6, and the New Horizons probe. These missions have supported military communications, scientific exploration, and technology demonstration.

### Launch Sites
The Atlas V 551 is launched from Cape Canaveral Space Force Station and Vandenberg Space Force Base in the United States, providing flexibility for various mission profiles.

### Retirement
The Atlas V 551 has been retired from active service, with newer configurations of the Atlas V now in use. This transition reflects ongoing advancements in launch vehicle technology and mission requirements.

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