# Myojo

> Japanese spacecraft used to evaluate performance of the H-II rocket

**Wikidata**: [Q11279320](https://www.wikidata.org/wiki/Q11279320)  
**Source**: https://4ort.xyz/entity/myojo

## Summary  
Myojo (also known as the Vehicle Evaluation Payload or VEP) is a Japanese spacecraft launched on 3 February 1994 to assess the performance of the H‑II launch vehicle. Operated and manufactured by the National Space Development Agency of Japan, it weighed 2 391 kg at launch and was carried aboard an H‑II‑1F rocket from the Yoshinobu Launch Complex.

## Key Facts  
- **Launch date:** 3 February 1994 (22:20 UTC) from Yoshinobu Launch Complex, Launch Pad 1.  
- **Launch vehicle:** H‑II family, specifically the H‑II‑1F configuration.  
- **Mass at launch:** 2 391 kg (launch weight).  
- **Operator & manufacturer:** National Space Development Agency of Japan (NASDA).  
- **COSPAR ID / NSSDC ID:** 1994‑007B.  
- **Country of origin:** Japan.  
- **Primary purpose:** Evaluate the performance of the H‑II rocket system.  
- **Instance of:** Spacecraft (vehicle designed to fly in space).  
- **Aliases:** Vehicle Evaluation Payload (VEP).  
- **Significant event:** Rocket launch at Yoshinobu Launch Complex, associated with the OREX (Orbital Re-entry Experiment) program.

## FAQs  
### Q: What was the main mission of Myojo?  
**A:** Myojo was a test payload designed to evaluate the performance and reliability of Japan’s H‑II launch vehicle during its inaugural flight.

### Q: When and where was Myojo launched?  
**A:** It launched on 3 February 1994 at 22:20 UTC from Launch Pad 1 of the Yoshinobu Launch Complex in Japan.

### Q: Who built and operated Myojo?  
**A:** The spacecraft was built and operated by Japan’s National Space Development Agency (NASDA).

## Why It Matters  
Myojo played a pivotal role in Japan’s early space launch capabilities by providing critical data on the H‑II rocket’s performance. As the first dedicated evaluation payload for this launch system, it helped validate design parameters, assess launch dynamics, and inform subsequent improvements to the H‑II family. The successful flight demonstrated Japan’s growing autonomy in access to space, laying groundwork for later scientific, commercial, and exploratory missions. By confirming the reliability of the H‑II vehicle, Myojo contributed directly to the expansion of Japan’s satellite deployment capacity and its reputation as a competent spacefaring nation.

## Notable For  
- First dedicated performance‑evaluation payload for the H‑II launch vehicle.  
- Served as a testbed for technologies later used in the OREX re‑entry experiment.  
- Launched aboard the inaugural H‑II‑1F configuration, marking a milestone in Japan’s launch vehicle development.  
- Provided baseline data that shaped subsequent H‑II missions and payload designs.  

## Body  

### Overview  
Myojo (Vehicle Evaluation Payload, VEP) is classified as a spacecraft—a vehicle engineered to operate in outer space. Its primary objective was to gather telemetry and performance metrics during the first flight of Japan’s H‑II launch system.

### Technical Specifications  
- **Mass:** 2 391 kg (launch weight).  
- **Country of origin:** Japan.  
- **COSPAR ID / NSSDC ID:** 1994‑007B.  
- **Operator & Manufacturer:** National Space Development Agency (NASDA).  

### Launch Details  
- **Date & Time:** 3 February 1994, 22:20 UTC.  
- **Launch Site:** Yoshinobu Launch Complex, Launch Pad 1.  
- **Launch Vehicle:** H‑II family, specifically the H‑II‑1F variant.  

### Mission Context  
The launch was recorded as a significant event within the OREX (Orbital Re-entry Experiment) program, linking Myojo’s performance data to broader re‑entry and atmospheric studies. The successful deployment validated the H‑II rocket’s capabilities, enabling Japan to proceed with more complex satellite missions.

### Legacy  
Myojo’s data informed engineering refinements for later H‑II flights, contributing to the reliability of Japan’s launch infrastructure. Its role as a test payload set a precedent for systematic performance evaluation in subsequent Japanese space endeavors.

## References

1. [Source](https://space.skyrocket.de/doc_sdat/vep.htm)
2. Jonathan's Space Report