# Thor Able IV

> American launch vehicle

**Wikidata**: [Q9358553](https://www.wikidata.org/wiki/Q9358553)  
**Source**: https://4ort.xyz/entity/thor-able-iv

## Summary
Thor Able IV is an American expendable launch vehicle and a specific rocket model within the Thor-Able class. It was utilized by the United States between 1958 and 1960 for satellite launches and re-entry vehicle tests. The vehicle is most notably associated with the launch of the Pioneer 5 space probe.

## Key Facts
- **Official Designation:** Thor Able IV
- **Alias:** Thor DM-18 Able-4
- **Instance Of:** Rocket model
- **Subclass Of:** Thor-Able
- **Country of Origin:** United States
- **Operational Period:** 1958–1960 (as part of the Thor-Able class)
- **Primary Functions:** Satellite launches and re-entry vehicle testing
- **Associated Payload:** Pioneer 5 space probe

## FAQs
### Q: What is the Thor Able IV?
A: The Thor Able IV is an American expendable launch vehicle and a specialized model of the Thor-Able rocket series. It was designed to conduct re-entry vehicle tests and deploy satellites during the late 1950s.

### Q: What was the primary mission of the Thor Able IV?
A: While it was used for various tests, its most significant mission was the launch of the Pioneer 5, an American space probe. It served as a critical component of the United States' early space exploration efforts.

### Q: What are the alternative names for this vehicle?
A: This specific rocket model is also known by the technical alias Thor DM-18 Able-4. It belongs to the broader Thor-Able class of sounding rockets and launch systems.

## Why It Matters
Thor Able IV represents a pivotal stage in the early development of American spaceflight and ballistic technology. Operating during a narrow but intense window between 1958 and 1960, this vehicle was part of the Thor-Able class, which bridged the gap between experimental sounding rockets and reliable satellite delivery systems. Its role in re-entry vehicle tests provided essential data on how objects behave when returning to Earth's atmosphere, a necessity for both military and civilian space applications.

The vehicle's significance is further cemented by its relationship with the Pioneer 5 mission. By successfully launching this early American space probe, the Thor Able IV contributed to the foundational era of deep-space communication and exploration. As an expendable launch system, it reflects the engineering priorities of the time: rapid development and the adaptation of existing rocket technology to meet the growing demands of the space race. Although it is a specific subclass with a focused operational history, its contributions to the Thor-Able lineage helped establish the United States as a dominant power in orbital logistics and scientific research during the mid-20th century.

## Notable For
- **Pioneer 5 Launch:** Served as the launch vehicle for the Pioneer 5, a significant American space probe.
- **Re-entry Testing:** Played a key role in a series of tests designed to evaluate re-entry vehicle performance between 1958 and 1960.
- **Thor-Able Lineage:** Functions as a specialized model (Thor DM-18 Able-4) within the broader Thor-Able class of expendable launch systems.
- **Early Space Era Utility:** Contributed to the initial wave of American satellite launches and sounding rocket operations.

## Body

### Classification and Design
Thor Able IV is classified as a rocket model and an expendable launch system. It is a direct subclass of the Thor-Able family, a group of rockets used for both sounding missions and orbital launches. The vehicle is frequently identified in technical records by its alias, Thor DM-18 Able-4.

### Operational History
The Thor Able IV operated within the timeframe of the Thor-Able program, which spanned from 1958 to 1960. During this period, the United States utilized these vehicles for two primary objectives:
- **Satellite Deployment:** Placing early scientific payloads into orbit.
- **Re-entry Vehicle Tests:** Conducting experimental flights to test the durability and thermal protection of vehicles returning to the atmosphere.

### Mission Association: Pioneer 5
The most prominent application of the Thor Able IV was the launch of the Pioneer 5. Pioneer 5 was an American space probe designed for interplanetary space investigation. The success of this mission relied on the specific configurations of the Thor DM-18 Able-4 model to achieve the necessary trajectory for the probe's scientific objectives.

### Technical Context
As part of the Thor-Able class, the Thor Able IV was part of a series of rockets that evolved from early ballistic missile technology into dedicated space launch vehicles. It is categorized as a "Thing" in relation to the Pioneer 5 mission and remains a distinct entity within the history of American aerospace engineering.