Jason-3

Jason-3 is a satellite altimeter created by a partnership of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and National Aeronautic and Space Administration (NASA), and is an international cooperative mission in which National Oceanic and Atmospheric Administration (NOAA) is partnering with the Centre National d'Études Spatiales (CNES, French space agency). The satellite's mission is to supply data for scientific, commercial, and practical applications to sea level rise, sea surface temperature, ocean temperature circulation, and climate change.

Jason-3 makes precise measurements related to global sea-surface height. Because sea surface height is measured via altimetry, mesoscale ocean features are better simulated since the Jason-3 radar altimeter can measure global sea-level variations with very high accuracy. The scientific goal is to produce global sea-surface height measurements every 10 days to an accuracy of less than 4 cm. In order to calibrate the radar altimeter, a microwave radiometer measures signal delay caused by atmospheric vapors, ultimately correcting the altimeter's accuracy to 3.3 cm. This data is important to collect and analyze because it is a critical factor in understanding the changes in Earth's climate brought on by global warming as well as ocean circulation. NOAA's National Weather Service uses Jason-3's data to more accurately forecast tropical cyclones.

The primary users of Jason-3 data are people who are dependent on marine and weather forecasts for public safety, commerce and environmental purposes. Other users include scientists and people who are concerned with global warming and its relation to the ocean. National Oceanic and Atmospheric Administration (NOAA) and European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) are using the data primarily for monitoring wind and waves on the high seas, hurricane intensity, ocean surface currents, El Niño and La Niña forecasts, water levels of lakes and rivers. Jason-3 also reports on environmental issues such as algae blooms and oil spills. NASA and CNES are more interested in the research aspect, in terms of understanding and planning for climate change. Jason-3 can measure climate change via sea surface height because sea surface rise, averaged over annual time scales, is accelerated by warming global temperatures. Ultimately, the benefits of Jason-3 data will transfer to people and to the economy.

Jason-3 flies at the same 9.9-day repeat track orbit and this means the satellite will make observations over the same ocean point every 9.9 days. The orbital parameters are: 66.05º inclination, 1,380 km apogee, 1,328 km perigee, 112 minutes per revolution around Earth. It was set to fly 1 minute behind the now decommissioned Jason-2. The 1-minute time delay was applied in order to not miss any data collection between missions.

In order to detect sea level change, we need to know the orbit height of the satellites as they revolve around Earth, to within 1 cm (0.4 inches). Combining instruments from three different techniques—GPS, DORIS, LRA. The GPS receiver on Jason-3 uses data from the constellation of GPS satellites in orbit to constantly determine its position in orbit. Similarly, DORIS is another system to help determine orbit positioning. Designed by CNES in France, DORIS uses the Doppler effect to found its system, which describes the differences in frequencies of waves between source and object. Thirdly, LRA (Laser Retroreflector Array), which is an instance of satellite laser ranging (SLR), uses corner reflectors on board the satellite to track the time it takes for lasers shot from Earth to reach the satellite and be reflected back, which can then be analyzed to understand the orbital positioning of Jason-3 from ground tracking stations. These three techniques (GPS, DORIS, LRA) all aid in determining orbit height and positioning.

Appearing on the SpaceX manifest as early as July 2013, Jason-3 was originally scheduled for launch on 22 July 2015. However, this date was pushed back to 19 August 2015 following the discovery of contamination in one of the satellite's thrusters, requiring the thruster to be replaced and further inspected. The launch was further delayed by several months due to the loss of a Falcon 9 rocket with the CRS-7 mission on 28 June 2015.

After SpaceX conducted their return-to-flight mission in December 2015 with the upgraded Falcon 9 Full Thrust, Jason-3 was assigned to the final previous-generation Falcon 9 v1.1 rocket, although some parts of the rocket body had been reworked following the findings of the failure investigation.

A 7-second static fire test of the rocket was completed on 11 January 2016. The Launch Readiness Review was signed off by all parties on 15 January 2016, and the launch proceeded successfully on 17 January 2016, at 18:42 UTC. The Jason-3 payload was deployed into its target orbit at 830 mi (1,340 km) altitude after an orbital insertion burn about 56 minutes into the flight. It was the 21st Falcon 9 flight overall and the second into a high-inclination orbit from Vandenberg Air Force Base Space Launch Complex 4E in California.