# STP P78-2
**Wikidata**: [Q2205291](https://www.wikidata.org/wiki/Q2205291)  
**Source**: https://4ort.xyz/entity/stp-p78-2

## Summary
STP P78-2, also known as Spacecraft Charging at High Altitude (SCATHA), was a U.S. scientific spacecraft launched in 1979 to study electrical charging phenomena in the magnetosphere. It provided critical data to improve the design and durability of satellites in high-altitude orbits. Launched aboard a Delta 2000 rocket, it operated in an elliptical orbit to analyze interactions between spacecraft and the space environment.

## Key Facts
- **Launch Date**: January 30, 1979  
- **Launch Vehicle**: Delta 2000 rocket  
- **Launch Site**: Cape Canaveral Space Launch Complex 17  
- **COSPAR ID**: 1979-007A  
- **NSSDCA ID**: 1979-007A  
- **Primary Mission**: Investigate spacecraft charging effects in high-altitude orbits  
- **Orbit**: Elliptical (perigee: 180 km, apogee: 8,000 km)  

## FAQs
### Q: What was the main purpose of the STP P78-2 mission?
A: The mission aimed to study electrical charging of spacecraft in high-altitude orbits to address anomalies observed in earlier satellite operations, ensuring more reliable spacecraft design.

### Q: Where and when was STP P78-2 launched?
A: It launched on January 30, 1979, from Cape Canaveral Space Launch Complex 17 aboard a Delta 2000 rocket.

### Q: What makes STP P78-2 significant in space research?
A: It was the first mission dedicated to understanding spacecraft charging at high altitudes, providing foundational data that improved satellite safety and performance in harsh space environments.

## Why It Matters
STP P78-2 played a pivotal role in advancing space technology by addressing critical challenges related to spacecraft charging. This phenomenon, caused by interactions between satellites and the magnetosphere, could lead to electrical discharges and system failures. By conducting detailed measurements in a high-altitude orbit, the mission generated essential insights that informed the development of protective shielding and discharge mitigation strategies. Its findings directly contributed to the longevity and reliability of subsequent satellites, particularly those operating in geostationary or polar orbits. The data from STP P78-2 remains a reference for spacecraft design, ensuring modern missions can withstand the rigors of the space environment.

## Notable For
- First dedicated mission to study spacecraft charging at high altitudes.  
- Provided comprehensive data on electron interactions and plasma dynamics in the magnetosphere.  
- Operated in an elliptical orbit spanning 180 km to 8,000 km to capture varied environmental conditions.  
- Directly influenced the design of protective systems for satellites in high-altitude missions.  

## Body
### Mission Overview
STP P78-2 was part of the U.S. Space Test Program (STP) and launched under the name "Spacecraft Charging at High Altitude" (SCATHA). Its primary objective was to investigate electrical charging phenomena affecting satellites in high-altitude orbits, a critical issue identified during earlier missions like the ATS-5 and SCATHA's predecessor, P78-1.

### Launch Details
- **Date**: January 30, 1979  
- **Rocket**: Delta 2000 (configuration 2914)  
- **Launch Pad**: Cape Canaveral SLC-17  
- **Payload Mass**: 300 kg (approximate)  

### Technical Specifications
- **Instruments**: 
  - Plasma detectors  
  - Electric field sensors  
  - Charge measurement devices  
- **Orbit**: 
  - Perigee: 180 km  
  - Apogee: 8,000 km  
  - Inclination: 30°  

### Legacy
The mission's data resolved key questions about spacecraft charging mechanisms, enabling engineers to develop strategies to prevent arcing and material degradation. Its findings were applied to subsequent satellite programs, including the Defense Satellite Communications System (DSCS) and commercial communications satellites, reducing operational risks in high-altitude environments. STP P78-2 demonstrated the importance of environmental testing for spacecraft, shaping standards for modern orbital missions.

## References

1. Jonathan's Space Report