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Jason-1 was a joint mission between NASA and the French Space Agency (Centre national d'études spatiales, or CNES) serving as a follow-on altimetric mission to the TOPEX/Poseidon mission. It launched on December 7, 2001, and began data collection on January 15, 2002.

Jason-1 was capable of measuring significant wave height, sigma naught (sigma0), dry and wet troposphere and ionosphere, which can be used to calculate sea surface height and anomalies and total electron content. Jason-1 had a repeat period of approximately 10 days with 254 passes per cycle.

Type

Earth Observation Satellite

Data Center

PO.DAAC

Launch

December 7, 2001

Objective

Mapping sea level, wind speed, and wave height
The French Space Agency (Centre national d'études spatiales, or CNES) is a programmatic agency, field center, and space operator encompassing all of the functions required to shape and execute the French government’s space strategy.
Centre National d'Etudes Spatiales (CNES) Logo

After the launch of OSTM/Jason-2 on June 20, 2008, and several successful months of data collection, Jason-1 was moved to a new interleaved orbit in relation to the Ocean Surface Topography Mission (OSTM). Originally they were in tandem. Jason-1 began maneuvering to the new orbit on January 26, 2009 (cycle 260) and the altimeter was placed in standby, i.e., no altimeter data collection. 

On February 10, 2009, the altimeter was turned back on, but Jason-1 was still maneuvering to the new orbit. The maneuver was completed on February 14, 2009, and cycle 263 was the first complete cycle for the new orbit.

After experiencing multiple safeholds, in February and March of 2012, it was decided by the project that Jason-1 should enter into a new orbit that was more conducive for geodetic studies. The basis for this decision was to ensure the safety of the orbit used by OSTM/Jason-2 and future missions, such as Jason-3 and Jason-CS. This new orbit provided an opportunity to study the marine geodetic field in more detail. The geodetic mission began on May 7, 2012, at cycle 500. 

The regular Jason-1 mission ended with cycle 374 pass 173 on March 3, 2012. It then took Jason-1 406 days to complete a cycle, but the data were separated into 11 days sub-cycles, as opposed to the 10 days cycle in the previous orbit. There were now 140 revolutions or 280 passes per 11 days cycle. Since the 11 days cycle was really a sub-cycle there wouldn't be a co-located repeat of the same numbered passes as in the previous orbit, i.e., cycle 500 pass 10 is not located over the same area as cycle 501 pass 10.

Contact was lost with the Jason-1 spacecraft on June 21, 2013, and it was decommissioned on July 1, 2013.

Text in the far-right column refers to the Geodetic mission, cycle 500 and onward.

Semi-major axis7,714.43 km7,702.437 km
Eccentricity9.5 E-51.3 to 2.8 E-4
Inclination66.04°66.042°
Argument of periapsis90.0° 
Inertial longitude of the ascending node116.56° 
Mean anomaly253.13° 
Reference altitude1,336 km1,324.0 km
Nodal period6,745.72 sec6,730 sec
Repeat period9.9156 days406 days
Geodetic sub-Cycles 3.9, 10.9, 47.5 179.5 days
Number of revolutions within a cycle127 
Number of passes within a cycle254 
Equatorial cross track separation315 km 
Ground track control band+1 km 
Acute angle at Equator crossings39.5° 
Longitude of Equator crossing of pass 1,
cycles 1-365
99.9249° 
Longitude of Equator crossing of pass 1,
cycles 369-375
98.5° 
Inertial nodal rate-2.08°/day 
Orbital speed7.2 km/s 
Ground track speed5.8 km/s 
  • Additional information about instruments, orbit, or other properties of Jason-1 can be found in the Handbook.
  • Additional information about the geodetic orbit can be found in the technical note.

The following resources provide additional information about Jason-1.

Instruments Aboard Jason-1

Instrument Name Operational Date(s) Spectral Resolution Type of Instrument
Jason-1 Microwave Radiometer 2002 - 2013

3 frequencies: 18.7, 23.8, and 34 GHz

Spectrometer/Radiometer
Poseidon-2 2002 - 2013

Microwave: Ku-band (13.575 GHz), C-band (5.3 GHz)

Altimeter

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