NASA has chosen SpaceX to launch a pair of small satellites to study space weather as part of a joint mission in 2025. On September 29, NASA announced that it had ordered SpaceX to launch the Tandem Reconnection and Cusp Electrodynamic Reconnaissance Satellites (TRACERS), a pair of small satellites that will study space weather and the magnetosphere from low Earth orbit.

NASA selected TRACERS as the Small Explorer, or SMEX, heliophysics mission in 2019, costing no more than $115 million. It was later planned to be launched as an auxiliary payload along with another SMEX mission, the Corona and Polarimeter to Unify the Heliosphere (PUNCH). But in August 2022, NASA announced that PUNCH would fly on the same Falcon 9 as the agency’s astrophysics mission, the History of the Universe Spectro-Photometer, Reionization Era, and Ice Explorer (SPHEREx), in 2025.

NASA’s TRACERS launch announcement did not specify how the spacecraft would be launched other than Falcon 9, nor did it specify a launch date. NASA representative Lyjay Lockhart said on September 29 that TRACERS will be the main payload of the joint mission, which will enter sun-synchronous orbit before April 2025.

As with previous awards under the Enterprise Class Dedicated and Vehicle Sharing (VADR) contract, NASA declined to disclose the value of the task order, saying such information was “competitive information” that could affect bids for future orders. NASA added $3.593 million to SpaceX’s VADR contract on Sept. 26 but did not tie it directly to the TRACERS order, according to the government’s procurement database.

Once placed in a sun-synchronous orbit, the two spacecraft will make multiple passes at polar altitude through Earth’s magnetosphere, studying the interaction between the solar wind and Earth’s magnetosphere, known as magnetic reconnection, as field lines bend toward the north and south poles.

The mission is led by David Miles of the University of Iowa, who took over as principal investigator following the death in August of Craig Kletzing, also of the University of Iowa. The spacecraft is being built by Millennium Space Systems. Source