NASA scientists are using commercial small satellite data to improve Earth science research in many disciplines. In one such example, researchers used small satellite data to improve the detection and prediction of landslides in high mountain Nepal. In another, these data were used to assess the water quality of major lakes in the United States. For both of these projects, the temporal frequency and spatial resolution of small satellite data improved the accuracy of the research and complemented data from NASA’s Earth observing satellites.
NASA's Commercial Smallsat Data Acquisition (CSDA) Program was established to identify, evaluate, and acquire data and imagery from commercial sources that support NASA's Earth science research and application goals.
To help researchers find and download commercial small satellite data, the CSDA data management team at NASA’s Marshall Space Flight Center in Huntsville, Alabama, has developed the Smallsat Data Explorer (SDX).
SDX makes datasets purchased by CSDA available to current and future NASA-funded researchers. This new user-friendly tool allows researchers to explore and order catalogued small satellite data from multiple commercial vendors in one place. Researchers can search the catalogue of CSDA data and imagery by defining an area of interest and specifying the date and cloud cover constraints (in the case of imagery). More information on how to use the SDX can be found in the User Guide.
Spire and Planet Data
CSDA has catalogued Planet imagery and Spire Global Navigation Satellite Systems (GNSS) data in the SDX, which are hosted in the NASA cloud.
Spire Global’s constellation receives signals transmitted by multiple GNSS constellations, including the U.S. Navstar Global Positioning System (GPS).
As the signal between the GNSS satellite travels through the atmosphere it is refracted. Spire small satellites in low Earth orbit receive the refracted signal and measure the magnitude of refraction, which provides researchers with information on the temperature and water vapor content of different levels of the atmosphere. GNSS data can be retrieved from small satellites every few hours, as opposed to data from satellites that both send and receive signals, which may only make observations every few days.
Three principal investigators (PIs) for CSDA pilot projects used Spire GNSS data to study atmospheric dynamics. Reflected GNSS signals can also be used to study ocean wind speeds, soil moisture, and sea surface height. A PI for the CSDA pilot used reflected GNSS signals from Spire to get sea surface height measurements for ocean altimetry applications.
At the time of the initial purchase of Spire data by CSDA, there was no suitable location to host (or archive) and distribute Spire data. The SDX now provides such a place for data discovery and distribution. Spire data are available from November 2019 to present, with a 30-day latency.
Planet imagery is available in the SDX from PlanetScope, SkySat, and RapidEye. Researchers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland assessed the utility of PlanetScope and RapidEye imagery for detecting and accurately predicting landslides in support of disaster mitigation and response efforts. They were able to detect up to 94 percent more landslides compared to Landsat-8 and 74 percent more when compared to Sentinel-2.
Scientists with the SERVIR program, a joint initiative of NASA and the U.S. Agency for International Development (USAID), used PlanetScope imagery to help pastoralists in Senegal identify small watering holes for their cattle.
Adding Vendor Data
The CSDA data management team is working to catalog small satellite data as it becomes available to CSDA. More information on CSDA datasets is available on Earthdata. Maxar data will be added to the SDX in the coming months for researcher access. Through collaboration with the International Space Station (ISS), data from the Teledyne Brown Engineering, Inc., DLR Earth Sensing Imaging Spectrometer (DESIS) are also available to NASA-funded researchers and will be added to the SDX.