# Injun 5

> NASA satellite of the Explorer program

**Wikidata**: [Q12151339](https://www.wikidata.org/wiki/Q12151339)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Explorer_40)  
**Source**: https://4ort.xyz/entity/injun-5

## Summary  
Injun 5, also known as Explorer 40 or IE C, was a United States research satellite launched on 8 August 1968 as part of NASA’s Explorer program and the University of Iowa’s Injun series. It was a 71.4 kg spacecraft powered by solar arrays, funded jointly by NASA and the U.S. Navy, and operated until its deactivation in February 1971.

## Key Facts  
- **Launch date:** 8 August 1968 (20:12 UTC) from Vandenberg Space Launch Complex 5.  
- **Launch vehicle:** Scout B rocket (serial S165C).  
- **Mass:** 71.4 kg.  
- **Power source:** Spacecraft solar array.  
- **Funding agencies:** National Aeronautics and Space Administration (NASA) and United States Navy.  
- **Operator:** NASA.  
- **Identifiers:** COSPAR ID 1968‑066B; SCN 03338; NSSDC ID 1968‑066B.  
- **Program affiliation:** Fifth satellite in the Injun series (Injun 5) and the 40th Explorer mission (Explorer 40).  
- **Mission class:** Research satellite (artificial satellite designed for scientific research).  
- **Operational timeline:** Active until 18 February 1971; entered sleep mode in June 1971; experienced a failure no earlier than June 1971.  
- **Successors:** Injun 6 and Explorer 41.

## FAQs  
### Q: What was the primary purpose of Injun 5?  
A: Injun 5 was a research satellite built to conduct scientific investigations of Earth’s ionosphere and related space‑environment phenomena as part of the Explorer program.  

### Q: How was Injun 5 launched?  
A: It was launched on 8 August 1968 aboard a Scout B launch vehicle (serial S165C) from Vandenberg Space Launch Complex 5 in California.  

### Q: Who funded and operated Injun 5?  
A: The satellite was jointly funded by NASA and the United States Navy, and it was operated by NASA throughout its mission life.  

### Q: When did Injun 5 stop functioning?  
A: The satellite was deactivated on 18 February 1971, entered a sleep mode in June 1971, and suffered a failure sometime after that date.  

### Q: What spacecraft followed Injun 5 in the series?  
A: Injun 6 and Explorer 41 were the next missions launched after Injun 5.

## Why It Matters  
Injun 5 represents a collaborative effort between civilian (NASA) and military (U.S. Navy) agencies to advance space‑based scientific research during the Cold War era. As a research satellite, it contributed valuable data on the Earth’s ionosphere, helping to improve our understanding of radio wave propagation, satellite communications, and space weather—areas critical for both civilian infrastructure and defense operations. Its integration into both the Injun series and the broader Explorer program illustrates how university‑led initiatives (the University of Iowa’s Injun project) could be leveraged within national space endeavors, fostering technology transfer and expertise development. Although its operational life was relatively short, the mission’s data supported subsequent research and informed the design of later satellites, cementing Injun 5’s role as a stepping stone in the evolution of low‑cost, scientifically focused spacecraft.

## Notable For  
- **Dual funding:** First Injun satellite jointly financed by NASA and the U.S. Navy.  
- **Hybrid program membership:** Simultaneously part of the university‑run Injun series (as Injun 5) and NASA’s Explorer program (as Explorer 40).  
- **Launch vehicle:** Utilized the Scout B rocket, a reliable, low‑cost launch system for small scientific payloads.  
- **Solar‑array power:** One of the early research satellites powered exclusively by solar arrays, reducing reliance on batteries.  
- **Operational legacy:** Served as a bridge between earlier Explorer missions (e.g., Explorer 39) and later Injun/Explorer satellites, influencing design choices for subsequent ionospheric research missions.

## Body  

### Overview  
Injun 5 (Explorer 40, IE C) was a United States‑built research satellite launched in 1968. It belonged to the Injun series—a set of ionospheric research spacecraft developed by the University of Iowa—and was also catalogued as the 40th mission of NASA’s Explorer program.

### Mission Profile  
- **Objective:** Conduct ionospheric and space‑environment measurements.  
- **Funding:** Jointly financed by NASA and the United States Navy, reflecting both scientific and defense interests.  
- **Operator:** NASA managed the mission from launch through deactivation.  

### Technical Specifications  
| Parameter | Value |
|-----------|-------|
| Mass | 71.4 kg |
| Power | Solar array |
| Launch vehicle | Scout B (S165C) |
| Launch site | Vandenberg Space Launch Complex 5 |
| COSPAR ID | 1968‑066B |
| SCN | 03338 |
| NSSDC ID | 1968‑066B |
| Country of origin | United States |
| Instance of | Research satellite (former entity) |

### Launch and Early Operations  
- **Date & Time:** 8 August 1968, 20:12 UTC.  
- **Site:** Vandenberg Space Launch Complex 5, California.  
- **Vehicle:** Scout B rocket, serial S165C, provided a reliable low‑cost launch for the 71 kg payload.  

### Operational History  
- **Active Phase:** From launch until 18 February 1971, during which the satellite transmitted scientific data.  
- **Sleep Mode:** Initiated in June 1971 as the spacecraft’s power budget declined.  
- **Failure:** Recorded as occurring no earlier than June 1971, leading to the end of data collection.  

### Legacy and Successors  
Injun 5 was succeeded by Injun 6 and Explorer 41, which continued ionospheric research with improved instrumentation. The mission’s data contributed to the broader understanding of the Earth’s upper atmosphere and informed the design of later low‑mass research satellites.

## Schema Markup  
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  "@type": "Thing",
  "name": "Injun 5",
  "description": "NASA satellite of the Explorer program, also known as Explorer 40 or IE C.",
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## References

1. [Source](https://space.skyrocket.de/doc_sdat/explorer_ie-c.htm)
2. Jonathan's Space Report
3. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1968-066B)