NASA and the European Space Agency (ESA) are set to launch Sentinel-6B, a satellite designed to monitor sea levels across over 90% of the Earth's oceans. This mission is a crucial step in maintaining a long-standing dataset for sea level measurements, which will significantly impact public safety, city planning, and the protection of coastal infrastructure. The satellite, weighing approximately 2,600 pounds (1,200 kilograms) when fully fueled, will be launched from Vandenberg Space Force Base in California aboard a SpaceX Falcon 9 rocket.
The launch is scheduled for 12:21 a.m. EST on Monday, November 17 (9:21 p.m. PST on Sunday, November 16). After a 57-minute journey, the satellite will separate from the rocket and begin its primary mission. It will orbit the Earth every 112 minutes at a speed of 4.5 miles (7.2 kilometers) per second, taking over from its predecessor, Sentinel-6 Michael Freilich, which was launched five years ago.
The Sentinel-6B satellite will provide primary sea level measurements, while Sentinel-6 Michael Freilich will be used for different scientific purposes, including mapping seafloor features. The data collected will be crucial for improving atmospheric models that support the safe return of Artemis astronauts. The satellite's measurements will also contribute to public safety and city planning, helping to protect critical infrastructure like power plants and defense installations.
The launch process is intricate, involving several stages. The satellite, measuring 19.1 feet (5.82 meters) in length and 7.74 feet (2.36 meters) in height, will lift off from Space Launch Complex 4 East at Vandenberg. Backup launch opportunities are available on subsequent days, with a 20-second launch window occurring about 12 to 13 minutes earlier each day.
After the Falcon 9 rocket lifts off, the main engine will cut off after a little over two minutes. The rocket's first and second stages will separate, followed by the second-stage engine starting. The reusable first stage will then perform an automated boost-back burn to the launch site for a powered landing. About three minutes after launch, the payload fairing, which protected the satellite during its ascent, will separate and fall safely back to Earth.
The satellite's solar panels will deploy about seven minutes after separation, and it is expected to make first contact with ground controllers about 35 minutes after separation (roughly an hour and a half after liftoff). This initial contact is a significant milestone, indicating that the spacecraft is functioning correctly.
Following the launch, the team will focus on preparing the spacecraft for science operations. Sentinel-6B will fly about 30 seconds behind its twin, Sentinel-6 Michael Freilich, and once the data from both satellites is cross-calibrated, Sentinel-6B will take over the primary role of sea level measurement. This transition will allow researchers to use Sentinel-6 Michael Freilich for various scientific purposes, including mapping the ocean floor.
For those interested in following the launch, coverage will be available on the agency's website (https://www.nasa.gov/live/Public Release). This mission is a testament to the collaboration between NASA and ESA, and the data collected will have far-reaching benefits for global safety and infrastructure.
