Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites

A computer simulation of the Earth's magnetic field. The lines represent magnetic field lines, blue when the field points towards the center and yellow when away.

TRACERS is a pair of identical spacecraft that will be launched as a secondary mission to another orbiter named Polarimeter to Unify the Corona and Heliosphere (PUNCH) and will operate in synergy; PUNCH will study the solar wind, a stream of charged particles emanating from the Sun, while TRACERS will study Earth's response.[4]

TRACERS will observe solar particles interacting with Earth's magnetic field at the northern magnetic cusp region. Here, the field lines guide particles from the boundary between Earth's magnetic field down into the atmosphere. In a process known as magnetic reconnection, the field lines violently reconfigure, sending particles out at speeds that can approach the speed of light. Some of these particles will be guided by the Earth's field into the region where TRACERS can observe them.[4]·[1] TRACERS will study a longstanding question about where reconnection happens at the magnetopause and how the solar wind affects the place and timing, helping NASA better forecast the influx of energetic particles into Earth's magnetic field that has the potential to disrupt the power grid and satellite communications.[4]·[3] TRACERS and PUNCH will work well together with the other existing heliophysics spacecraft.[1]

On 20 June 2019, NASA announced that PUNCH and TRACERS were the winning candidates to become the next missions in the agency's Small Explorer program, to be launched together in February 2023. The twin TRACERS spacecraft will carry instruments built by the University of California Berkeley, Space Sciences Laboratory (SSL).[3]

• Heliophysics
• Magnetospheric Multiscale Mission
• Solar storm