US, European mission preps for Sentinel-6 launch

The satellite, known as Sentinel-6 Michael Freilich and jointly developed by Europe and the United States, contains cutting-edge instruments able to capture sea surface height with unprecedented accuracy, adding to space-based measurements going back almost 30 years.

Berlin: A "climate guardian" satellite set for launching this weekend will greatly help scientists keep track of the rise in sea levels, one of the most daunting effects of global warming, a senior official at the European Space Agency said on Friday.

“This is an extremely important parameter for climate monitoring,” said Josef Aschbacher, the European Space Agency's director of Earth observation.

Billions of people living in coastal areas around the planet are at risk in the coming decades as melting polar ice and ocean expansion caused by warming push waters ever higher up the shore.

Sentinel-6 Michael Freilich

“We know that sea level is rising,” Aschbacher said. The big question is, by how much, how quickly.

Some studies estimate the world’s oceans will rise by at least 2 feet (61 centimetres) by the end of the century, hitting low-lying regions from Bangladesh to Florida.

Aschbacher said measurements dating back to the 1990s show average sea levels rising first by about 3 millimetres (0.12 inches) per year, but in the past couple of years, the annual rate was almost 5 millimetres (0.2 inches).

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While measurements are also taken at ground level, in harbours and other coastal areas, they don’t provide the same precise uniform standard as a single satellite sweeping the entire globe every 10 days, he said.

“If you measure it at sea level, you have one measurement device in Amsterdam and you have a different one in Bangkok and yet another one in Miami," Aschbacher told The Associated Press by video from ESA offices in Frascati, Italy. "But with a satellite, you can compare these measurements globally because it’s the same instrument that flies over all these areas.”

The probe's most powerful weapon is the Poseidon-4 radar altimeter, named after the trident-wielding Greek god of the sea. The instrument measures how long it takes for radar signals to bounce off the sea surface and back to the satellite.

The new satellite will also collect measurements at a higher resolution than its predecessors, allowing researchers to peer more closely at small ocean features, especially along the coastlines.

Other instruments onboard will measure how radio signals pass through the atmosphere, providing data on atmospheric temperature and humidity that can help improve global weather forecasts.

The satellite is due to be carried into orbit Saturday from Vandenberg Air Force Base in California aboard a SpaceX Falcon 9 rocket. The European Space Agency this week lamented the loss of two satellites when a European-built carrier rocket veered off course shortly after launch.

“ This failure on Monday reminded us how risky the space business is,″ Aschbacher said. "We are always at the edge."

Sentinel-6 is named after the late director of NASA’s Earth Science Division, Michael Freilich, an oceanographer who was key to getting the U.S. space agency to join the mission.

“We owe him a lot and he more than deserves to have this satellite named after him,” said Aschbacher. “I’m very sorry personally that he cannot push the button tomorrow.”

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Europe and the United States are sharing the 900-million-euro ($1.1-billion) cost of the 10-year mission, which includes the launch of an identical twin, currently called Sentinel-6B, in 2025.

It’s the first time that another space agency has been involved in ESA’s flagship Copernicus program, which already has seven satellites in orbit measuring the seas, atmosphere and land. Some data collected by the ESA and other agencies recently showed the impact of the coronavirus pandemic as seen from space.

Aschbacher said he hopes NASA and ESA will team up on future missions, too.

“NASA is our strongest partner internationally,” he said. “We are discussing right now other options of cooperation based on the model of Sentinel 6-Michael Freilich.”

The two space agencies recently agreed to cooperate on a planned NASA outpost around the moon.

But Aschbacher said lunar missions and others looking to Mars and beyond, shouldn't divert attention from the need to keep an eye on our planet.

“We all know that (Earth) is undergoing enormous changes, extremely fast changes and changes we never had before on this planet with a speed and intensity caused, obviously, by humans," he said. "And we need to understand how this planet functions for our survival, for our future.”

AP