SpaceX Launch in Doubt as Weather Threatens Sea-Level Mission

• A SpaceX Falcon 9 rocket is scheduled to launch the Sentinel-6B satellite, a critical international mission to monitor rising sea levels.
• The launch from Vandenberg Space Force Base, California, faces a significant 60% probability of being scrubbed due to severe weather systems on the West Coast.
• This mission marks a major milestone: the 500th flight of a previously flown Falcon 9 booster, which will attempt to land back near the launch pad.
• The Sentinel-6B is the second satellite in a billion-dollar collaboration between the United States and Europe to continue decades of sea height measurement.

A crucial international mission to monitor the Earth's rising sea levels is at risk of delay as SpaceX prepares to launch the Sentinel-6B satellite amidst unfavorable weather conditions in California. The launch, scheduled for Sunday at 9:21 p.m. PST from Vandenberg Space Force Base, faces a high probability of a weather-related postponement.

Weather Poses Major Threat

Meteorologists with the U.S. Space Force’s Space Launch Delta 30 have put the probability of a weather rule violation at a staggering 60 percent. A series of potent low-pressure systems has brought unusually heavy rainfall to the West Coast, creating a challenging environment for a rocket launch.

“California has been one of the wettest places in the United States this weekend, even wetter than, say, the Midwest, which is really abnormal for Southern California,” explained Launch Weather Officer 1st Lt. William F. Harbin during a pre-launch briefing. Should the launch be delayed by 24 hours, conditions are forecast to improve slightly, with the chance of a violation dropping to 40 percent.

A Historic Flight for a Reused Rocket

The mission is not only scientifically significant but also marks a landmark achievement for SpaceX. The Falcon 9 first stage designated for this flight, serial number B1097, will be making its third trip to space. More importantly, this mission will be the 500th time SpaceX has launched a previously flown Falcon 9 booster, a testament to its pioneering reusable rocket technology. If the launch proceeds as planned, the booster is expected to perform a return-to-launch-site landing, touching down just 1,400 feet from where it lifted off.

A Falcon 9 rocket stands at pad 4E at Vandenberg Space Force Base ahead of the planned launch of the Sentinel-6B mission. Image: SpaceX.

The Sentinel-6B and its International Partners

The Sentinel-6B satellite is the centerpiece of a billion-dollar international effort, with costs split between the United States and Europe. It joins its twin, Sentinel-6 Michael Freilich, which launched five years ago. The collaboration includes NASA, the European Space Agency (ESA), Eumetsat, NOAA, the European Commission, and the French space agency CNES.

A Watchful Eye on Our Oceans

Built by Airbus Defence and Space, the spacecraft will be deployed into a circular orbit 830 miles high about 57 minutes after liftoff. From this vantage point, Sentinel-6B will use advanced, cloud-penetrating radar to measure sea level heights with an accuracy of down to an inch across 90 percent of the world's oceans.

“This information lets us monitor significant ocean features like ocean currents, sea level and wave height, and gives us a view into the inner workings of the ocean,” said Karen St. Germain, NASA’s director of Earth science. She added that this data is fundamental for everything from commercial fishing and shipping to predicting floods for coastal communities.

Artist’s impression of the Sentinel-6B spacecraft separating from the Falcon 9’s second stage. Image: ESA.

Notably, in line with Trump Administration policies, official mission briefings have avoided mentioning climate change, which the vast majority of scientists identify as the primary driver of rising sea levels that the Sentinel mission is designed to track.