_Hypatia II crew members fix the base of the corner reflector. © Hypatia Mars._ A corner reflector was installed at the Mars Desert Research Station (MDRS) in Utah, USA, on February 2025. It was part of [Hypatia Mars](https://hypatiamars.com/) II analog mission, which took place from 2-15 February. Located at 7.8 km and 5.7 km away respectively from Sentinel-3A & B ground tracks, the MDRS offers an interesting spot to conduct additional calibration activities for Sentinel-3, and possibly, other satellite missions carrying radar sensors such as altimeters. The corner is paired with a GNSS antenna that provides the exact position of the device. _Location of the corner reflector with respect to the ground tracks of Sentinel-3A (red) and Sentinel-3B (blue). © isardSAT_ The corner reflector has been developed by isardSAT and funded by the European Space Agency - ESA, as an extension of the [Sentinel-3 Land Altimetry Mission Performance Cluster Service](https://www.isardsat.cat/project/s3mpc-land)  project. It has been installed and set up by Hypatia II crew, as part of the second mission of Hypatia Mars, a female-led organisation dedicated to advancing Martian research and outreach. _Crew of Hypatia II in the Mars Desert Research station premises. © Hypatia Mars_

__ The first successful results of the calibration site installed at the Mars Desert Research Station (MDRS) show the potential of the infrastructure to reinforce Sentinel-3 calibration network. The system was ready since 14 February, carrying out a first test with a Sentinel-3B overpass. Subsequent passes show very positive results, as seen in the Sentinel-3B of 6 May, which recorded exceptional signal reflection characteristics, with radar cross-section measurements matching expected values. As more data will be collected over time, this permanent infrastructure will allow a long-term monitoring of the Sentinel-3 radar altimeters performance, as well as other satellite missions. _Hypatia II crew installing the corner reflector. © Marta Ferrer. _ This corner reflector installed at the Mars Desert Research Station represents a new addition to the the network of Sentinel-3 calibration sites. Thanks to its geographical location, it will also strengthen the global network of corner reflectors for satellite altimeter calibration, providing data from a new longitude. The corner reflector has been developed by isardSAT and funded by the European Space Agency - ESA, as an extension of the [Sentinel-3 Land Altimetry Mission Performance Cluster Service ](https://www.isardsat.cat/project/s3mpc-land)project. It has been installed and set up by Hypatia II crew, as part of the second mission of Hypatia Mars, a female-led organisation dedicated to advancing Martian research and outreach. _Hypatia II manipulating the GNSS station. © isardSAT _ Mònica Roca i Aparici, one of the crew members of Hypatia II and co-founder of isardSAT, a Barcelona-based enterprise provider of EO solutions, explains that “with this initiative, we have been able, on the one hand, to consolidate innovative satellite calibration methodologies. And, on the other hand, to take a step further towards defining how satellite calibration beyond Earth could work”.