Research project IM/RT/23/SORBET (Research action IM)
The BRAMS (Belgian RAdio Meteor Stations) network is a research infrastructure developed by BIRA-IASB since 2010, funded by BIRA-IASB, STCE and the BRAIN-Be project METRO. It uses forward scatter of VHF radio waves on ionized meteor trails to detect and characterize meteoroids falling into the Earth’s atmosphere and to estimate their impact on the upper atmosphere. The network currently comprises a transmitter and 46 receiving stations (most in Belgium, a few in France, Luxembourg, the Netherlands). One of the receiving stations is an interferometer.
Two methods have recently been developed to reconstruct meteoroid trajectories and speeds using BRAMS data. The first one uses time delay observations between the appearances of meteor echoes of at least 6 BRAMS receiving stations. A second method using the radio interferometer requires only 3 additional detections from BRAMS receivers. Both methods are now complemented with use of the pre-t0 phase technique which provides an additional constraint on the meteoroid speed. A comparison with optical observations confirms that both methods provide accurate speed and inclination.
With these tools now in hand, the next step is to bring BRAMS from research to operations and to provide services to space operators, scientists, and the public. These services are based on the derived data described below:
1) Trajectories, speeds and orbital parameters of meteoroids are important for the astronomical community to study meteoroid dynamics, detect new meteor showers and to identify parent bodies.
2) Temperature and wind speeds in the Mesosphere - Lower Thermosphere : since meteoroids ablate around 85-105 km altitude, they sample this region inaccessible to balloons or spacecraft. From the characteristics of meteor echoes one can derive the temperatures and wind speeds at those altitudes, a task routinely done using meteor radars but that we will adapt for a forward scatter system such as BRAMS. The main advantage is to provide such measurements with a higher spatial resolution and wider coverage area, taking advantage of the large number of BRAMS receivers. We will offer this as a service to modellers of the global atmospheric circulation.
3) Meteor fluxes are crucial for space companies since meteoroids pose a threat to spacecraft. We will envisage how to develop or be included in a service providing meteoroid impact risk for a given spacecraft geometry and orbital characteristics (Earth orbit). Being involved in scientific space instruments, our Institute is increasingly confronted with the need to provide such impact risk assessments.
In order to better reach these objectives, we will first expand the BRAMS network to fully benefit from the newly developed algorithms by adding a second interferometer and a second transmitter, and by increasing the power of the current transmitter.
