NASA, European Partners Set to Launch Sentinel-6B Earth Satellite

The mission, designed to monitor sea levels in more than 90% of Earth's oceans, must first enter orbit. Here's what to expect.

Sentinel-6B, an ocean tracking satellite jointly developed by NASA and ESA (European Space Agency), is ready to be sent to the launch pad, packaged in the payload fairing of a SpaceX Falcon 9 rocket.

Launch is scheduled for 12:21 pm EST on Monday, November 17 (9:21 pm PST on Sunday, November 16). After liftoff from Vandenberg Space Force Base in California, the satellite will undergo a 57-minute sequence of events ending with the separation of the spacecraft, when the satellite separates from the rocket.

Then the real work of Sentinel-6B begins. Orbiting Earth every 112 minutes at a speed of 4.5 miles (7.2 kilometers) per second, the satellite will eventually replace its twin, Michael Freilich's Sentinel-6, launched five years ago to continue its decades-long collection of sea level measurements from space. These measurements, along with the atmospheric data the mission collects, will help improve public safety and urban planning while protecting coastal infrastructure, including power plants and defense interests. NASA will also use this data to refine atmospheric models that will ensure the safe return of Artemis astronauts to the atmosphere.

Here's a closer look at what's in store for the satellite in the coming days.

Measuring 19.1 feet (5.82 meters) long and 7.74 feet (2.36 meters) tall (including communications antennas), the satellite weighs about 2,600 pounds (1,200 kilograms) when loaded with propellant at launch.

The satellite will launch from Spaceport 4 Vostok in Vandenberg. If required, backup starting capabilities are available on subsequent days, with the 20-second starting window occurring approximately 12 to 13 minutes earlier each day.

Just over two minutes after liftoff, the Falcon 9 rocket shuts down its main engine. Shortly after this, the first and second stages of the rocket separate, followed by the ignition of the second stage engine. The reusable Falcon 9's first stage then begins an automatic return to the launch pad for a forced landing. About three minutes after launch, the two halves of the payload fairing that protected the satellite during its flight through the atmosphere separate and fall safely back to Earth.

The first shutdown of the second stage engine occurs approximately eight minutes after liftoff, after which the launch vehicle and spacecraft will be in a temporary “parking” orbit. About 44 minutes later, the second stage engine fires a second time, and about 57 minutes after liftoff, the rocket and spacecraft separate. About seven minutes later, the satellite's solar panels will deploy. Sentinel-6B is expected to make first contact with ground controllers about 35 minutes after separation (about an hour and a half after liftoff), a major milestone indicating the spacecraft is healthy.

After launch, the team will focus on the next task: preparing the spacecraft for science operations. Once in orbit, Sentinel-6B will fly about 30 seconds behind its twin, the Sentinel-6 Michael Freilich satellite. Once scientists and engineers complete cross-calibration of the data collected by the two spacecraft, Sentinel-6B will take over the role of providing primary sea level measurements, and Sentinel-6 Michael Freilich will move to a different orbit. The researchers then plan to use measurements from Michael Freilich's Sentinel-6 for a variety of purposes, including mapping seafloor features (changes in sea surface elevation can reveal changes in ocean floor features such as seamounts).

A report on the mission's launch on launch day will be available on the agency's website. websiteincluding links to live streams and blog updates that will begin no earlier than 11:00 PM EST on November 16th, when the countdown milestones occur. Streaming video and photos of the launch will be available on demand shortly after launch. Follow the NASA news countdown Blog Sentinel-6B.

For more information on NASA's livestream schedule, visit
plus.nasa.gov/scheduled-events.

The Copernicus Sentinel-6/Jason-CS (Continuity of Service) mission is a collaboration between NASA, ESA, EUMETSAT (the European Organization for the Exploitation of Meteorological Satellites) and the National Oceanic and Atmospheric Administration (NOAA). The European Commission provided financial support and the French space agency CNES (National Center for Space Research) provided technical expertise. The mission also marks the first international participation in Copernicus, the European Union's Earth observation program.

Caltech's Pasadena JPL division built three science instruments for each Sentinel-6 satellite: Advanced Microwave Radiometer, Global Navigation Satellite System – Radio OccultationAnd Laser retroreflector grating. NASA also provides launch services, ground systems supporting NASA's science instruments, science data processors for two of these instruments, and support for US members of the International Ocean Surface Topography and Sentinel-6 science teams. The launch service is managed by NASA's Launch Services Program, based at the agency's Kennedy Space Center in Florida.

News Media Contacts

Elizabeth Vlok
NASA Headquarters, Washington
202-358-1600
[email protected]

Andrew Wang / Andrew Good
Jet Propulsion Laboratory, Pasadena, California.
626-379-6874 / 626-840-4291
[email protected] / [email protected]

2025-125