BDS-3’s Short Message Aids Space Exploring

At 15:11 on January 20, BDS-3 downlinked in a quasi-real-time manner the observation alarms for Gamma-ray burst detected by its GECAM satellite to the Scientific Operation Center, initiating the application of BDS-3 global short messages in space science and space exploring.

Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor (Huairou-1 Far-sight Telescope, GECAM) was the first user of BDS-3 global short message services, and is also the first space astronomical telescope for instantly downlinking observation data. Satellites generally downlink scientific data only when they fly over the ground receiving station, which causes long time delay (up to several hours, and even over 10 hours) and makes quick response impossible. To meet the demand for scientific observation, the GECAM satellite creatively uses the communication links of BDS-3 global short messages to downlink key scientific data related to the burst of celestial power to the ground in a quasi-real-time manner, realizing quick guidance for follow-up observation of other equipment.

The burst of celestial power detected by the GECAM satellite is a Gamma-ray one (No. GRB 210120A). It occurred at 15:10:48.550 (Beijing time) on January 20, 2021. The GECAM satellite captured in real time this burst event through the on-board on-orbit trigger positioning software, and downlinked the positioning results, light curves, and other observation alarm information to the ground via BDS-3. The Scientific Operation Center for the GECAM satellite received the first BDS short message within about 60s after triggering, and then complete the reception of all short messages within 10 minutes. The transmission of short messages was normal, and relevant performance indicators met design requirements.

This test proves that BDS-3 short message services have broad application prospects in space science. It is learned that BDS-3 global short message services will be applied in the future Einstein Probe (EP) and the enhanced X-ray Timing and Polarimetry (eXTP) space observatory to quickly report key information about the burst of celestial power and guide other equipment for follow-up observation.