NASA and its European partners are set to launch Sentinel-6B, the next spacecraft in a decades-long effort to track global sea levels and improve understanding of Earth’s changing oceans. Liftoff was targeted for 12:21 a.m. EST this morning, November 17 (9:21 p.m. PST on Nov. 16) from Vandenberg Space Force Base in California aboard a SpaceX Falcon 9 rocket.
Sentinel-6B is the twin of Sentinel-6 Michael Freilich, which launched in 2020. Together, the satellites extend a more than 30-year record of precision sea-level measurements that help scientists monitor climate change, support coastal planning, and refine atmospheric models. Once in orbit, Sentinel-6B will eventually assume the primary role in collecting global sea-surface height data, while its predecessor shifts into a new orbit for complementary scientific work.
The spacecraft, weighing about 2,600 pounds and measuring over 19 feet long, is currently packed within the Falcon 9 payload fairing for rollout to the pad. After liftoff, the mission will follow a tightly choreographed 57-minute ascent sequence. Two minutes into flight, the rocket’s first stage will shut down and separate before navigating back to Vandenberg for a powered landing. Meanwhile, the second stage will continue its push to orbit, pausing briefly in a “parking” orbit before a final burn sends the spacecraft on its way.
Separation between the rocket and the satellite is expected 57 minutes after launch, followed by solar array deployment about seven minutes later. Initial contact with ground controllers is expected to occur approximately 90 minutes after liftoff, marking a key milestone that confirms the spacecraft’s health.
Once operational, Sentinel-6B will orbit Earth every 112 minutes, traveling at 4.5 miles per second. Flying about 30 seconds behind its twin, it will undergo a cross-calibration period to ensure seamless continuity in the sea-level record. The data collected will support storm forecasting, protect coastal infrastructure, and help guide commercial shipping and resource management.
The mission is a collaboration among NASA, ESA, EUMETSAT, NOAA, the European Commission, and France’s CNES. NASA’s Jet Propulsion Laboratory contributed three science instruments and oversees U.S. science operations, while NASA’s Launch Services Program is managing the launch.
Source: NASA