ESA is launching an Announcement of Opportunity for the international scientific community to access data from the Spire mission for science and applications development. 

• Polarimetric Radio Occultations (PRO) datasets over a historical period spanning 15 May 2023 to 30 November 2023. The PRO measurements observe the properties of Global Navigation Satellite System (GNSS) signals as they pass through Earth's atmosphere, similar to regular RO measurements. The polarization state of the signals is recorded separately for Horizontal (H) and Vertical (V) polarizations to provide information on the anisotropy of hydrometeors along the propagation path. The PRO measurements add a sensitivity to ice and precipitation content alongside the traditional RO measurements of the atmospheric temperature, pressure, and water vapour.

• Near-Nadir GNSS Reflectometry (NN GNSS-R) datasets covering from 25 January 2024 until 24 July 2024. NN GNSS-R measurements track the surface reflections as observed by the near-nadir pointing GNSS-R antennas, based on Delay Doppler Maps (DDMs), and allow to measure ocean surface winds and characterize land surfaces for applications such as soil moisture, freeze/thaw monitoring, flooding detection, inland water body delineation, sea ice classification, etc.

• Grazing angle GNSS Reflectometry (GA GNSS-R) datasets covering from 25 January 2024 until 24 July 2024. GA GNSS-R measurements are tracks of surface reflections as observed by the limb-facing RO antennas, based on open-loop tracking outputs, 50 Hz collections of accumulated I/Q observations. The GA GNSS-R measurements are used to characterize land surfaces for applications such as sea ice classification, freeze/thaw monitoring, inland water body detection and delineation, etc., and to measure relative altimetry with dm-level precision for inland water bodies, river slopes, sea ice freeboard, etc., but also water vapour characterization from delay based on tropospheric delays.

Data are available to order on demand upon submission of a Project Proposal subject to evaluation and acceptance by ESA and Spire.  

How to Access Data

1. Go to the ESA User Services Portal
2. Register or log in to EO Sign In
3. After logging in, complete and submit the form with your proposed use of the data
4. The proposal will be evaluated by ESA, which normally takes between 4 and 6 weeks
5. Upon successful evaluation, you will receive a confirmation email, which describes the amount of data to be provided, and details of how to order the data.

The Spire Announcement of Opportunity Call is open to users located in ESA Member States (including Canada) and in European Commission Member States, with a proposal submission deadline of 31 March 2025.