OVERVIEW

SCIENCE

TECHNOLOGY

NEWSROOM

EDUCATION

GALLERY

There is also a PDF version of the Fact Sheet.

Objectives

- Three-year global view of Earth's oceans
- Improved understanding of ocean currents
- Improved forecasting of global climate

Mission

- Joint NASA-CNES program
- Launched August 10, 1992
- Launch Vehicle: Arianespace's Ariane 42P
- Launch Site: Centre Spatial Guyanais, Kourou, French Guiana
- Operations for 3-year prime mission, 6-year extended: JPL
- Orbit: 1336-km, circular, 66° inclination
- 10-day repeat of ground track (±1-km accuracy)
- Covers 95% of ice-free oceans every 10-days

Spacecraft

- Based on Fairchild's Multi-Mission Spacecraft bus
- Total mass: 2402 kg (5296 lbs)
- Single solar panel provides 3.4 kW of power
- 1.2 m (4 foot) high-gain antenna communicates through TDRSS
- Reaction wheels and torque rods maintain 3-axis stabilization and nadir pointing
- Hydrazine propellant system provides orbital maintenance

Payload/Sensors

- NASA dual-frequency (C- and Ku-band) altimeter and CNES single-frequency (Ku-band) solid-state altimeter measures height above sea
- NASA microwave radiometer measures water vapor along altimeter path to correct for pulse delay
- NASA Global Positioning System demonstration receiver provides precise orbit ephemeris data
- NASA laser retroreflector array works with ground stations to track satellite and calibrate and verify altimeter measurements.
- CNES DORIS Doppler tracking antenna receives ground signals for precise orbit determination, satellite tracking, and ionospheric correction data for CNES altimeter

Data

- Sea-level measurement accuracy 4.2 cm (1.7 inch)
- Data coverage global between 66°N and 66°S latitude
- Data availability through NASA/JPL and CNES