# Explorer S45

> Its mission was to investigate the shape of the ionosphere. The spacecraft did not achieve orbit.

**Wikidata**: [Q113273955](https://www.wikidata.org/wiki/Q113273955)  
**Source**: https://4ort.xyz/entity/explorer-s45

## Summary  
Explorer S45 was a NASA spacecraft launched in 1961 with the objective of investigating the shape of the ionosphere. It failed to achieve orbit and was ultimately unsuccessful in completing its mission.

## Key Facts  
- Launched on February 24, 1961  
- Mission goal was to study the shape of the ionosphere  
- Failed to reach orbit  
- Launched from Cape Canaveral Space Launch Complex 17  
- Used the Juno rocket as its launch vehicle  
- NSSDCA ID: EXS-451  
- Classified as a spacecraft  

## FAQs  
### Q: What was the purpose of Explorer S45?  
A: Explorer S45 was designed to investigate the shape of the ionosphere, a region of the Earth's upper atmosphere.  

### Q: Did Explorer S45 successfully complete its mission?  
A: No, Explorer S45 did not achieve orbit and therefore failed to complete its mission.  

### Q: When and where was Explorer S45 launched?  
A: Explorer S45 was launched on February 24, 1961, from Cape Canaveral Space Launch Complex 17.  

## Why It Matters  
Explorer S45 represents an early attempt by NASA to understand the Earth’s ionosphere—a critical layer of the atmosphere affecting radio communications and satellite operations. Though it failed to achieve orbit, it contributed to the broader learning curve of early space missions during the formative years of the U.S. space program. Failures like Explorer S45 helped engineers refine launch procedures, spacecraft design, and mission planning, which were essential for the success of later exploratory missions. It also reflects the rapid pace of experimentation during the early 1960s space race, where both successes and failures advanced scientific understanding.

## Notable For  
- One of several early Explorer program missions focused on atmospheric science  
- Failed to reach orbit despite being part of NASA's successful Explorer series  
- Used the Juno launch vehicle, which had mixed success in early flights  
- Represents early challenges in achieving precise orbital insertion  

## Body  
### Mission Overview  
Explorer S45 was developed under NASA's Explorer program, which aimed to conduct scientific investigations in space. The primary scientific objective of Explorer S45 was to examine the geometric properties of the ionosphere using onboard instrumentation.

### Launch Details  
The spacecraft was launched on February 24, 1961, at 15:10 UTC from Cape Canaveral Space Launch Complex 17. It utilized the Juno rocket (specifically the Juno I variant) as its launch vehicle. Despite a successful liftoff, the mission failed to place the spacecraft into orbit due to either a malfunction in the launch vehicle or the spacecraft itself.

### Technical Specifications  
- NSSDCA Identifier: EXS-451  
- Instance Of: Spacecraft  
- Launch Vehicle: Juno I  
- Launch Site: Cape Canaveral LC-17  

### Outcome  
Explorer S45 did not achieve orbit and was unable to return any scientific data. The failure highlighted ongoing technical challenges in early orbital mechanics and spacecraft deployment systems. No further information regarding recovery or debris has been reported.

### Historical Context  
During the early 1960s, the United States was rapidly expanding its space capabilities. Missions like Explorer S45 were part of a broader effort to understand near-Earth space environments. While many early missions experienced similar failures, each contributed valuable engineering insights that led to more reliable future missions.