18 juin 2008

But all obstacles in its way have now been cleared and Jason-2 is sitting atop the 2nd stage of the Delta II launcher, patiently awaiting lift-off on 20 June.
Cooked all round
55 minutes into the flight, the satellite will separate from the launcher and then turn on all axes like an irregularly-shaped stone as it is placed in a temporary orbit 10 km below that of Jason-1. Its solar arrays will then start to unfurl and Jason-2 will go into “barbecue mode”, alternately exposing its different sides to the sunlight.

Over the next 3 days the Satellite Control Centre in Toulouse, France, will activate and check out instruments.
The last crucial phase for CNES teams will consist in positioning Jason-2 just minutes behind Jason-1 in a nearly identical orbit. The two satellites will fly in tandem for 6 to 9 months, during which Jason-2’s instruments will be cross-calibrated with Jason-1’s.
The last crucial phase for CNES teams will consist in positioning Jason-2 just minutes behind Jason-1 in a nearly identical orbit. The two satellites will fly in tandem for 6 to 9 months, during which Jason-2’s instruments will be cross-calibrated with Jason-1’s.
Orbital trade-offs
The more often a satellite revisits the same point on the globe, the fewer points it sees and vice-versa. The chosen orbit is therefore a trade-off between revisit frequency and spatial resolution. Jason-2 will orbit at high altitude (1,336 km) to alleviate the effects of atmospheric and gravity disturbances and to facilitate orbit determination, inclined 66° to the equator to cover almost all of Earth’s ice-free sees. This means it will return to the same point every 10 days, flying a trajectory optimized to study large-scale ocean variability.
When the cross-calibration process is complete, Jason-1 will be moved aside to a parallel ground track midway between two adjacent Jason-2 ground tracks to increase global data coverage and optimize spatial resolution. Jason-1 and Jason-2 data will also be combined with data from Envisat.
When the cross-calibration process is complete, Jason-1 will be moved aside to a parallel ground track midway between two adjacent Jason-2 ground tracks to increase global data coverage and optimize spatial resolution. Jason-1 and Jason-2 data will also be combined with data from Envisat.
Watch the Jason-2 launch live on 20 June from 9.10 a.m. CET on this site or on our oceanography blog.
More about
JASON, the ocean observatory
TOPEX/POSEIDON, the beginnings of satellite oceanography
How altimetry works
TOPEX/POSEIDON, the beginnings of satellite oceanography
How altimetry works
Related links
Previous news
Charting and forecasting ocean conditions
12 June 2008
A leap forward for oceanography
3 June 2008
Jason-2 : a family affair
27 May 2008
Jason-2: watching sea level and weather
20 May 2008
Jason-2 takes to the air
7 May 2008
12 June 2008
A leap forward for oceanography
3 June 2008
Jason-2 : a family affair
27 May 2008
Jason-2: watching sea level and weather
20 May 2008
Jason-2 takes to the air
7 May 2008