Sunday, November 22, 2020

NASA-ESA launch Sentinel-6 Michael Freilich satellite to monitor the oceans

A US-European satellite designed to extend a decades-long measurement of global sea surface heights was launched into Earth orbit from California on Saturday.

A SpaceX Falcon 9 rocket carrying the satellite blasted off from Vandenberg Air Force Base at 10:47 pm IST (9:17 am PST) and arced southward over the Pacific Ocean. The Falcon’s first stage flew back to the launch site and landed for reuse.

The Sentinel-6 Michael Freilich satellite was released from the second stage about an hour later. It then deployed its solar panels and made the first contact with controllers  at a ground station in Alaska

ESA and NASA launched the launch of #Sentinel6 Michael Freilich on Sunday. Image credit: ESA/Twitter

Sea-monitoring satellites

Sentinel-6a will be the first of two identical satellites -- the second to be launched in five years -- that will provide measurements of unprecedented precision until at least 2030.

The twin satellites will measure sea-level rise, tracking changes threatening to disrupt tens of millions of lives within a generation.

Each Sentinel-6 probe carries a radar altimeter, which measures the time it takes for radar pulses to travel to Earth’s surface and back again.

The satellites will circle the planet in the same orbit as earlier missions that supplied sea-surface height data over the last three decades, mapping 95 percent of Earth’s ice-free ocean every ten days.

Named for a former NASA official who had a key role in developing space-based oceanography, the satellite’s main instrument is an extremely accurate radar altimeter that will bounce energy off the sea surface as it sweeps over Earth’s oceans. Sentinel-6B will ensure continuity of the record.

The Copernicus Sentinel-6 mission is a collaboration of the European Commission, the European Space Agency (ESA), EUMETSAT, NASA and the US National Oceanic and Atmospheric Administration (NOAA).

The Sentinel satellites are each about the size and shape of a large minivan topped with slanted solar panels and weigh nearly 1,200 kilos, including rocket fuel.

They are designed to last for five-and-a-half years but could provide data for far longer. Europe and the United States are sharing the $1.1 billion (900 million euro) cost of the mission, which includes the twin satellite.

According to a statement by the ESA, over the last three decades, the French-US Topex-Poseidon and Jason mission series have been providing Space-based sea level measurements along with ESA’s earlier ERS and Envisat satellites and CryoSat and Copernicus Sentinel-3. These twin satellites will continue to provide data as accelerating sea-level rise is arguably the climate change impact that will affect the largest number of people over the next three decades.

Nearly 800 million people live within five metres of sea level, and even an increase in sea level of a few centimetres can translate into vastly more damage from high tides and storm surges.

Sea-surface heights are affected by heating and cooling of water, allowing scientist to use the altimeter data to detect such weather-influencing conditions as the warm El Nino and the cool La Nina.

The measurements are also important for understanding overall sea-level rise due to global warming that scientists warn is a risk to the world’s coastlines and billions of people.

“Our Earth is a system of intricately connected dynamics between land, ocean, ice, atmosphere and also, of course, our human communities, and that system is changing,” Karen St. Germain, NASA’s Earth Science Division director, said in a pre-launch briefing Friday.

“Because 70 percent of the Earth’s surface is the ocean, the oceans play an enormous role in how the whole system changes,” she said.

With inputs from wires



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