The SARAL/AltiKa mission: A step forward to the future of altimetry

The CNES/ISRO altimetric satellite SARAL/AltiKa was launched in February 2013 and since then has provided useful data for various scientific and operational applications in oceanography, hydrology, cryospheric sciences and geodesy. However, a Reaction Wheel problem forced relaxation of the repeatability constraint on the satellite's orbit, which has been drifting slowly since July 2016. Beyond the expected contributions of this mission and its very good integration into the objectives of the constellation of altimetric satellites, it has become more and more apparent that specific contributions and innovations related to the main specification of SARAL/AltiKa, that is to say the use of the Ka-band, have clearly emerged. The advantages of the Ka-band are in short the reduction of ionosphere effects, the smaller footprint, the better horizontal resolution and the higher vertical resolution. A drawback of the Ka-band is the attenuation due to water/water vapor in case of rain and the resulting loss of data. The main objective of this paper is to highlight the specific advances of the Ka-band in different scientific and technical fields and to show why they are promising for the future and open the way to several missions or mission projects. Although unplanned initially, the fine coverage of the Drifting Phase brings some interesting openings especially for geodesy and hydrology applications. (C) 2020 COSPAR. Published by Elsevier Ltd. All rights reserved.

Automated summary

The CNES/ISRO altimetric satellite SARAL/AltiKa, launched in February 2013, has provided valuable data for various scientific and operational applications. Despite the drift in the satellite’s orbit since July 2016, the specific contributions and innovations related to the use of the Ka-band have become increasingly prominent. The advantages of the Ka-band include reduced ionosphere effects and better resolution, but there are drawbacks such as attenuation during rain. This study aims to highlight the advancements of the Ka-band and its potential for future missions.