ACES mission moves closer to launch from ISS
by Erica Marchand
Paris, France (SPX) Mar 26, 2025

ESA's Atomic Clock Ensemble in Space (ACES) has reached NASA's Kennedy Space Center in Florida, marking a pivotal step in its upcoming deployment to the International Space Station. This European-led mission is designed to explore the boundaries of fundamental physics by measuring time from orbit with extraordinary accuracy.

Earlier in March, the ACES payload departed Europe and made its way across the Atlantic. Upon arrival in Florida, the unit was moved into the Space Station Processing Facility cleanroom, where it underwent a series of essential inspections and tests.

Specialists from ESA, Airbus, and NASA collaborated to carefully unbox and inspect the instrument, confirming its integrity after transport. Following the successful system verifications, the payload was resealed in its protective packaging and encased in a specialized magnetic shield known as "G-iron" to safeguard its highly sensitive atomic clocks.

The next stop for ACES is final integration with a SpaceX Falcon 9 rocket. Launch preparations are well underway, with liftoff planned for April 21. Once in orbit, ACES will be mounted on the exterior of ESA's Columbus module to begin its precision timing experiments.

Related Links
ESA Atomic Clock Ensemble in Space
Understanding Time and Space