# GRACE-2

> German/American science satellite

**Wikidata**: [Q46539486](https://www.wikidata.org/wiki/Q46539486)  
**Source**: https://4ort.xyz/entity/grace-2

## Summary
GRACE-2 (Gravity Recovery and Climate Experiment 2) was a German/American research satellite launched on March 17, 2002. It operated as part of a twin-satellite mission alongside GRACE-1, managed jointly by NASA and the German Aerospace Center (DLR). The spacecraft conducted scientific research for over 15 years before retiring and decaying from orbit in late 2017.

## Key Facts
- **Launch Date:** March 17, 2002, at 09:21:27 UTC.
- **Operators:** National Aeronautics and Space Administration (NASA) and German Aerospace Center (DLR).
- **Mission End:** Service retirement on October 27, 2017; atmospheric entry on December 24, 2017.
- **Identifiers:** COSPAR ID 2002-012B; NSSDCA ID 2002-012B; SCN 27392.
- **Aliases:** Gravity Recovery and Climate Experiment 2, ESSP-2B, Jerry.
- **Physical Specs:** Mass of 487 kg; Width 1.942 m; Height 0.72 m; Length 3.123 m.
- **Orbital Specs:** Apoapsis 508 km; Periapsis 483 km; Orbital period 94.5 minutes; Inclination 89.0 degrees.
- **Origin:** United States and Germany.
- **Manufacturers:** Space Systems (general contractor) and Lanteris Space Systems (subcontractor).

## FAQs
### Q: When was GRACE-2 launched and from where?
A: GRACE-2 was launched on March 17, 2002, from the Plesetsk Cosmodrome Site 133 in Russia.

### Q: Who built and operated the GRACE-2 satellite?
A: The satellite was manufactured by Space Systems and Lanteris Space Systems. It was jointly operated by the National Aeronautics and Space Administration (NASA) and the German Aerospace Center.

### Q: How long did GRACE-2 remain in service?
A: GRACE-2 provided scientific data from its launch in 2002 until its service retirement on October 27, 2017. It subsequently underwent atmospheric entry on December 24, 2017.

## Why It Matters
GRACE-2 represents a significant milestone in international aerospace collaboration, combining the expertise and resources of the United States and Germany. As one half of the Gravity Recovery and Climate Experiment mission, this research satellite utilized a specialized "Flexbus" spacecraft bus design to maintain a precise Sun-synchronous orbit for over 15 years. The longevity of the mission—far exceeding many standard satellite lifespans—allowed for the sustained collection of scientific data essential to its research objectives. The partnership between NASA and the German Aerospace Center (DLR) on this project serves as a prime example of cross-border cooperation in space exploration. The mission successfully concluded in 2017 with a planned retirement and atmospheric entry, marking the end of a durable and productive lifecycle in low Earth orbit.

## Notable For
- **International Collaboration:** A joint effort between the United States and Germany, operated by NASA and the German Aerospace Center (DLR).
- **Longevity:** Operated for over 15 years (2002–2017) despite the harsh conditions of low Earth orbit.
- **Twin Satellite Configuration:** Functioned as a paired unit with GRACE-1 as part of the broader Gravity Recovery and Climate Experiment.
- **Specific Design:** Utilized the "Flexbus" platform and was powered by solar cell panels with an average output of 620 watts.
- **Controlled End-of-Life:** The mission had a defined service retirement date followed by a tracked atmospheric entry.

## Body

### Mission Overview
GRACE-2 was an artificial satellite designed for scientific research, classed specifically as a research satellite. It was a component of the larger Gravity Recovery and Climate Experiment, operating in tandem with its counterpart, GRACE-1. The satellite was identified by various names, including ESSP-2B and the nickname "Jerry." It was categorized under the international identifiers COSPAR 2002-012B and NSSDCA 2002-012B, with a Satellite Catalog Number (SCN) of 27392.

### Development and Manufacturing
The spacecraft was a product of transatlantic cooperation, with its country of origin listed as the United States and Germany.
*   **General Contractor:** Space Systems
*   **Subcontractor:** Lanteris Space Systems
*   **Spacecraft Bus:** Flexbus

### Technical Specifications
GRACE-2 had a total mass of 487 kilograms. Its physical dimensions were:
*   **Length:** 3.123 metres
*   **Width:** 1.942 metres
*   **Height:** 0.72 metres
The satellite was powered by solar cell panels capable of generating 620 watts (Unit: Q25236).

### Orbital Profile
The satellite occupied a Sun-synchronous orbit around Earth with an inclination of 89.0 degrees and an eccentricity of 0.00182.
*   **Semi-major axis:** 6,873.5 km
*   **Apoapsis:** 508 km
*   **Periapsis:** 483 km
*   **Orbital Period:** 94.5 minutes

### Launch and Operations
GRACE-2 was launched on March 17, 2002, at 09:21:27 UTC. The launch vehicle was a Rokot (series of Russian space launch vehicles), contracted through Eurockot Launch Services. The launch took place at Plesetsk Cosmodrome Site 133. The epoch date for its orbital data was established on March 17, 2002, at 09:21:00.

### Decommissioning
The satellite's operational life concluded in late 2017.
*   **Service Retirement:** October 27, 2017.
*   **Atmospheric Entry:** December 24, 2017, at 00:16 UTC.
*   **Decay Location:** Latitude 63.9, Longitude -160.9.

## References

1. [Source](https://space.skyrocket.de/doc_sdat/grace.htm)
2. Jonathan's Space Report
3. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2002-012B)
4. [Source](https://www.space-track.org/basicspacedata/query/class/tip/NORAD_CAT_ID/27392/orderby/ID%20DESC/format/html/)
5. [Source](https://www.jpl.nasa.gov/news/news.php?feature=6984)
6. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=2002-012B)
7. [Source](https://www.jpl.nasa.gov/news/press_kits/gracelaunch.pdf)