ESA - Sentinel-6 updates

[jacqmans]

Sea-level monitoring satellite first results surpass expectations

10/12/2020

Launched less than three weeks ago, the Copernicus Sentinel-6 Michael Freilich satellite has not only returned its first data, but results also show that it is functioning far better than expected. Thanks to its new, sophisticated, altimetry technology, Sentinel-6 is poised to deliver exceptionally precise data on sea-level height to monitor the worrying trend of sea-level rise.

Sentinel-6 Michael Freilich was lofted into orbit on 21 November from California. After it had sent back its first signal showing that it was alive and well in space, ESA’s Operations Centre in Germany took care of the satellite’s first few days in orbit before handing it over to Eumetsat for commissioning, and eventual routine operations and distribution of data.

The satellite carries Europe’s latest radar altimetry technology to extend the long-term record of sea-surface height measurements that began in the early 1990s.

On 30 November, flight operators switched on Sentinel-6’s Poseidon-4 altimeter instrument, which was developed by ESA. Analysing its initial data, specialists were astonished by the quality. These first data were presented today, by way of three main images, at the European Space Week.


The first image (at the top and repeated to the left) shows some preliminary results of sea-surface height. The data are overlaid on a map showing similar products from all of the Copernicus altimetry missions: Jason-3, Sentinel-3A and Sentinel-3B. The background image is a map of sea-level anomalies from satellite altimeter data provided by the Copernicus Marine Environment Monitoring Service for 4 December 2020. The Sentinel-6 data products were generated on 5 December.

The image below shows a comparison between data processed on board the satellite and downlinked (blue line), compared to full raw data processed on the ground (red line). By removing the trailing edge of the data before being transmitted to Earth, the data rate is reduced by 50%. High fidelity low-noise data are thanks to Sentinel-6’s Poseidon-4 digital instrument architecture, which is a first. (Click on image for more information).


ESA’s mission scientist for Copernicus Sentinel-6, Craig Donlon, explained, “We can already see that the satellite is delivering incredible data, thanks to the digital architecture of Posiedon-4 and the inclusion of simultaneous high-resolution synthetic aperture radar processing and conventional low-resolution mode into altimetry for the first time. This gives us the opportunity to make measurements with much finer synthetic aperture radar techniques that can be compared to Jason-3 to understand the improvement of the climate record.”

“Importantly, we can also see that there is very little noise in the data, so we have extremely clean data to work with.”

The set of images below of Russia’s Ozero Nayval Lagoon and surrounding rivers show multiple views from Copernicus satellites. The first is a ‘camera-like’ image from Sentinel-2; the second is a radar image from Sentinel-1; and next is from Sentinel-6 in its conventional ‘low-resolution’ mode, which does not reveal a lot of information. However, by processing the altimetry data using fully-focussed synthetic aperture techniques usually used for imaging radar data, the resulting image reveals exceptional detail, highlighting the power of the instrument (click on image for more information).


Director of ESA’s Earth Observation Programmes, Josef Aschbacher, said, “We are delighted with these first results and proud to see our ESA-developed radar altimeter is working so well. Nevertheless, Copernicus Sentinel-6 is a mission that has been built in cooperation with the European Commission, Eumetsat, NASA, NOAA and CNES – with all parties playing essential roles that make this mission the success we are seeing today.”

Another surprising result suggests that the satellites position in space can be better understood than previously thought. A radar altimeter derives the height of the satellite above Earth by measuring how long a transmitted radar pulse takes to reflect from Earth’s surface. Sentinel-6 therefore carries a package of positioning instruments, including a system that can make use of both GPS and Galileo signals. Remarkably, the addition of Galileo measurements brings an improvement in orbit determination quality – which adds to the overall performance of the mission.

More about Copernicus Sentinel-6

Rising seas are at the top of the list of major concerns linked to climate change. Monitoring sea-surface height is critical to understanding the changes taking place so that decision-makers have the evidence to implement appropriate policies to help curb climate change and so that authorities can take action to protect vulnerable communities.

The first sea-surface height ‘reference’ measurements were supplied by the French–US Topex-Poseidon satellite, which was followed by three successive Jason missions. They show that since 1993 the global sea level has risen, on average, by just over 3 mm every year. Even more worryingly, over the last few years the global ocean has risen, on average, by 4.8 mm a year.

While the Copernicus Sentinel-6’s role is to continue this legacy of critical measurements, the satellite carries new digital altimeter technology with dedicated onboard processing that will return even more precise measurements of the height of the sea surface.

Sentinel-6 brings, for the first time, synthetic aperture radar into the altimetry reference mission time series. To ensure that the multi-satellite data time series remains stable, Sentinel-6 delivers simultaneous conventional low-resolution mode measurements, that are similar to measurements from Jason-3, as well as the improved performance of the synthetic aperture radar processing that yields high-resolution along-track measurements. A 12-month tandem flight, where Sentinel-6 flies just 30 seconds behind Jason-3, will be used to compare measurements from the two independent satellites in order to extend the sea-level climate record with confidence.

https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-6/Sea-level_monitoring_satellite_first_results_surpass_expectations

[jacqmans]

December 10, 2020
RELEASE 20-129

NASA, US, European Partner Satellite Returns First Sea Level Measurements

Sentinel-6 Michael Freilich, a joint U.S.-European satellite built to measure global sea surface height, has sent back its first measurements of sea level. The data provide information on sea surface height, wave height, and wind speed off the southern tip of Africa.

"We're excited for Sentinel-6 Michael Freilich to begin its critical work studying sea level and helping us understand the many aspects of our planet's global ocean," said Thomas Zurbuchen, NASA's associate administrator for science at the agency's headquarters in Washington. "I know Mike would be thrilled that the satellite bearing his name has begun operating, but he'd also be looking forward to studying the data from this important mission, as we all are."

Since the successful Nov. 21 launch from Vandenberg Air Force Base in California aboard a Space-X Falcon 9 rocket, engineers and scientists have spent several weeks switching on and checking out the satellite and its instruments, making sure everything is operating as it should.

"Christmas came early this year," said Josh Willis, project scientist at NASA's Jet Propulsion Laboratory in Southern California. "And right out of the box, the data look fantastic."

Sentinel-6 Michael Freilich will continue a decades-long effort to measure global ocean height from space, which started in the early 1990s. Since then, the rate of sea level rise has doubled with a current rate of 0.16 inches (4 millimeters) per year. The rise is caused almost entirely by a combination of meltwater from land-based glaciers and ice sheets and the fact that seawater expands as it warms.

"Data from Sentinel-6 Michael Freilich will help us evaluate how the Earth is changing," said Karen St. Germain, director of NASA's Earth Science Division. "When we combine the data from instruments like the altimeter on Sentinel-6 Michael Freilich with data from other satellites like GRACE-FO and IceSat-2, we can tell how much of the sea level rise is due to melting ice and how much is due to expansion as the oceans warm. Understanding these underlying physical mechanisms is what allows NASA to improve projections of future sea level rise.”

The initial orbit for Sentinel-6 Michael Freilich was 11.4 miles (18.4 kilometers) lower than its ultimate operational orbit of 830 miles (1,336 kilometers) above Earth. Engineers plan to move the satellite into its operational orbit by mid-December, where it will trail the Jason-3 satellite by 30 seconds. During this tandem flight, scientists and engineers will spend the next six to 12 months cross calibrating the data collected by both satellites to ensure the continuity of measurements between the two. Once assured of the data quality, Sentinel-6 Michael Freilich will then become the primary sea level satellite. The first publicly available sea level data will be available in about six months, with the rest available within a year.

"We are now gearing up the operational systems supporting the processing of the instruments' data by EUMETSAT and partner organizations, as they are all contributing to this complex process,” said Manfred Lugert, program manager for the Sentinel-6/Jason-CS (Continuity of Service) mission at the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) “This will keep us busy for the next few months, as the independent scientific validation and fine tuning need to be undertaken very carefully." Lugert expects the first operational products from the mission would be available to those who need them by mid-2021.

In addition to measuring sea level, Sentinel-6 Michael Freilich is monitoring atmospheric temperature and humidity, which will help improve weather and hurricane forecasts. Engineers and scientists turned on that instrument Nov. 27, and the initial data look good.

More About the Mission

Sentinel-6 Michael Freilich is named in honor of the former director of NASA's Earth Science Division, who was a leading figure in advancing ocean observations from space. Freilich passed away Aug. 5, 2020. "I think he would be proud," said Willis. "Like Mike himself, we expect great things from the satellite that bears his name, and so far, it's looking good."

The spacecraft is one of two identical satellites that will extend a nearly 30-year sea level record collected by an ongoing collaboration of U.S. and European satellites by another decade. That record began in 1992 with the TOPEX/Poseidon satellite and continued with Jason-1 (2001), OSTM/Jason-2 (2008), and Jason-3, which has been observing Earth's oceans since 2016. Sentinel-6 Michael Freilich will pass the baton to its twin, Sentinel-6B, in 2025.

Both spacecraft are a part of the Sentinel-6/Jason-CS mission, which will collect accurate measurements of sea surface height for more than 90% of the world's oceans. The satellites will also monitor atmospheric temperature and humidity, as well as wave height and wind speed, which will provide crucial information for operational oceanography, marine meteorology, and climate studies.

ESA (European Space Agency), EUMETSAT, NASA, and the National Oceanic and Atmospheric Administration (NOAA) are jointly developing the Sentinel-6/Jason-CS mission, with funding support from the European Commission and support from France's National Centre for Space Studies (CNES). The mission is part of Copernicus, the European Union's Earth observation program, which the European Commission manages.

NASA's contributions to the Sentinel-6/Jason-CS mission are three science instruments for each of the two satellites: the Advanced Microwave Radiometer for Climate, the Global Navigation Satellite System - Radio Occultation, and the Laser Retroreflector Array. NASA also contributed launch services, ground systems supporting operation of the NASA science instruments, the science data processors for two of these instruments, and support for the U.S. members of the international Ocean Surface Topography Science Team. NASA’s Jet Propulsion Laboratory at the California Institute of Technology in Pasadena manages the agency’s contribution to the mission.

For more information, visit:

https://www.nasa.gov/sentinel-6

https://www.esa.int/Sentinel-6

https://edefis.eu/CopernicusFactsheets

[jacqmans]

Galileo enhancing Sentinel-6’s sea level monitoring mission

15/12/2020

Just like your mobile phone, satellites themselves rely on satellite navigation to find their way in space. Thanks to a new ESA-developed receiver, the recently-launched Sentinel-6 is making use of Europe’s Galileo as well as the US GPS system, a fact set to sharpen the accuracy of its sea level rise measurements.

Copernicus Sentinel-6 Michael Freilich, launched on 21 November, is the world’s next radar altimetry reference mission, set to extend the legacy of sea-surface height measurements until at least 2030.

Developed by ESA with strong NASA support as part of Europe’s Copernics programme, the satellite is now being commissioned for operation by Eumetsat, Europe’s weather and climate satellite organisation.

Sentinel-6 is also the first Sentinel satellite equipped with a dual-system satnav receiver, which can make use of both GPS and Galileo signals, to perform mission-critical Precise Orbit Determination (POD).

The ESA-developed receiver’s first results became available on 26-27 November and underwent initial analysis by the Navigation Support Office based at ESA’s ESOC control centre in Germany, immediately revealing a very good data quality.

The receiver uses GPS and Galileo signals either separately or in combination. With Europe’s satnav system the world’s most precise, the Galileo POD measurements in particular were excellent, outperforming the GPS measurements by a factor of two in terms of accuracy.

Werner Enderle, Head of the Navigation Support Office comments: “While validation activities are still ongoing, the initial results of our Sentinel-6 precise orbit determination based exclusively on Galileo data are very exciting.”

Craig Donlon, Sentinel-6’s ESA Mission Scientist, explains that being able to more precisely fix the satellite’s position in space is crucial to mission success: “Sentinel-6 is a radar altimeter, measuring sea-surface height by sending down radar pulses to be bounced back to space, deriving the distance to the ocean surface to a few centimetres.


“But to know how far the signals have travelled we need to know the satellite’s orbital height to a high level of certainty. Such a high-performance satnav receiver that includes high-quality Galileo signals is likely to give us this information very precisely. Combined with the very low onboard noise of the altimeter instrument and its onboard processing facility, these are promising signs for the working mission to come.”

https://www.esa.int/Applications/Navigation/Galileo_enhancing_Sentinel-6_s_sea_level_monitoring_mission

[Jansen]

Crossposted from the launch thread:

https://twitter.com/eumetsat/status/1355121728473673732

Happy to announce all #Sentinel6 Michael Freilich in-orbit verification checks were a success! After the launch & transfer of operations from @esa, @eumetsat is now fully responsible for the operation of this @Copernicus mission. More #Sentinel6 info here: bit.ly/37pZLbD

[jacqmans]

Sentinel-6 passes in-orbit tests with flying colours
08/02/2021

In November 2020, the Copernicus Sentinel-6 Michael Freilich satellite was launched into orbit from the Vandenberg Air Force Base in California, US. Now, months later, the satellite has successfully passed what is known as the ‘in-orbit verification phase’, where its equipment is switched on and the instruments’ performance is checked.

The Copernicus Sentinel-6 Michael Freilich satellite is the first of two identical satellites to provide critical measurements of sea-level change. The satellite carries a new digital altimeter, Poseidon-4, that uses dedicated onboard processing to return even more precise measurements of the height of the sea surface.

In the satellite’s early days post-launch, the dedicated flight control team at ESA’s Operations Centre in Darmstadt, Germany, took meticulous care of the new Sentinel in what is known as the Launch and Early Orbit Phase (LEOP). Once completed, ESA’s mission control team handed over command and control of the satellite to Eumetsat – Europe’s weather and climate satellite organisation – who took over responsibility of commissioning, routine operations and distribution of the mission’s vital data.

On 27 January, ESA along with Sentinel-6’s key partners, including Airbus, Thales Alenia Space, Eumetsat, NASA, French Space Agency CNES and NOAA, completed the satellite’s ‘in-orbit verification phase’.

One of the tests performed included cross-calibrating the satellite’s altimeter data with measurements from the Copernicus Sentinel-3 and Jason missions. These tests are completed at ESA’s Permanent Facility for Altimetry Calibration (PFAC) in Crete, Greece, where the use of transponders are used to receive and re-transmit radar pulses back to the satellite in space to verify its performance.

These measurements have been used to demonstrate that the altimeter measurements are performing to expectation.

Robert Cullen, Copernicus Sentinel-6 Payload and System Manager at ESA, said, “From our preliminary analyses, the altimeter significant wave height and range uncertainty are significantly better compared to the previous Sentinel-3 and Jason-3 missions.”

Luisella Giulicchi, Copernicus Sentinel-6 System Manager at ESA, responsible for coordinating the satellite’s in-orbit verification phase, added, “We found all satellite subsystems to be working in perfect order. The satellite’s newly-deployed GNSS Precise Orbit Determination receiver, which combines both GPS and Galileo constellations signals, shows an outstanding preliminary performance, along with the rest of the navigation systems on board the satellite."

“Since 18 December, Sentinel-6 has been in its final orbit, trailing just 30 seconds behind Jason-3. This particular trailing formation is required for 12 months before Sentinel-6 Michael Freilich will take over from Jason-3 as the operational reference mission.”

More about Copernicus Sentinel-6

Rising seas are top of the list of major concerns linked to climate change. Monitoring sea-surface height is critical to understanding the changes taking place so that decision-makers have the evidence to implement policies to help curb climate change and so that authorities can take action to protect vulnerable communities.

The first sea-surface height ‘reference’ measurements were supplied by the French–US Topex-Poseidon satellite, which was followed by three successive Jason missions. They show that since 1993 the global sea level has risen, on average, by just over 3 mm every year. Even more worryingly, over the last few years the global ocean has risen, on average, by 4.8 mm a year. Copernicus Sentinel-6’s role is to continue this legacy of critical measurements.

https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-6/Sentinel-6_passes_in-orbit_tests_with_flying_colours

[jacqmans]

New sea-level monitoring satellite goes live
21/06/2021


Following liftoff last November and more than six months spent carefully calibrating the most advanced mission dedicated to measuring sea-level rise, Copernicus Sentinel-6 Michael Freilich is now operational – meaning that its data are available to climate researchers, ocean-weather forecasts and other data users.

Sentinel-6 is one of the European Union’s family of Copernicus missions but its implementation is the result of an exceptional cooperation between the European Commission ESA, Eumetsat, NASA and NOAA, with contribution from the CNES French space agency. The mission comprises two identical satellites launched five years apart: Copernicus Sentinel-6 Michael Freilich launched on 21 November 2020 and Copernicus Sentinel-6B, which will be launched in 2025.

Sea-level rise is a key indicator of climate change so accurately monitoring the changing height of the sea surface over decades is essential for climate science, for policy-making and, ultimately, for protecting the lives of those in low-lying regions at risk.

https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-6/New_sea-level_monitoring_satellite_goes_live

[bolun]

Sentinel-6B launch thread:

SpaceX F9 : Sentinel-6B : VSFB : 16/17 November 2025 (05:21 UTC)

https://forum.nasaspaceflight.com/index.php?topic=57922.0

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Sentinel-6B launched to extend record of sea-level rise

The latest guardian of our oceans has taken its place in orbit. The Copernicus Sentinel-6B satellite is now circling Earth, ready to continue a decades-long mission to track the height of the planet’s seas – a key measure of climate change.

Like its predecessor, Sentinel-6 Michael Freilich, Sentinel-6B carries the latest radar altimetry technology to further extend the sea-surface height record that began in the early 1990s. These measurements help scientists understand sea-level rise – crucial information for shaping climate policy and protecting the millions of people living in coastal areas around the world.

Image credit: ESA

[catdlr]

https://twitter.com/planet4589/status/1990507294237557228

Jonathan McDowell
@planet4589

Sentinel-6B cataloged in a 1308 x 1327 km x 66.1 deg orbit, confirming successful launch

[StraumliBlight]

https://twitter.com/eumetsat/status/1991507386830672365

EUMETSAT takes control of Copernicus Sentinel-6B [Nov 20]

After separation from the launcher, experts at ESA’s European Space Operations Centre (ESOC) in Darmstadt, Germany checked the spacecraft’s health and guided it towards its nominal orbit.

With control now transferred to EUMETSAT’s flight operations team, Copernicus Sentinel-6B will slowly reach its nominal orbit at 1,336 kilometres above Earth in mid December. From that it will fly in tandem with Sentinel-6 Michael Freilich, just 30 seconds apart, for several months. Together, the two satellites will ensure precise cross-calibration before Sentinel-6B becomes the new international reference mission for ocean altimetry.

At its core, Copernicus Sentinel-6B carries the Poseidon-4 radar altimeter, which measures sea-surface height by timing radar pulses reflected off the ocean. These data reveal changes in sea level, wave height, and surface wind speed — key inputs for weather forecasting, coastal protection and climate monitoring.

“This handover marks the start of Copernicus Sentinel-6B’s operational journey”, said Julia Figa Saldana, Ocean Altimetry Programme Manager at EUMETSAT. “Together with our European and US partners, we will soon begin the commissioning and calibration phase to ensure the mission continues the legacy of high-precision ocean measurements on which scientists, forecasters, and decision-makers rely. Our immediate focus is on validating the scientific information provided by the satellite and preparing for operational data delivery.”

[catdlr]

https://twitter.com/blueorigin/status/1996685022212874388

Blue Origin
@blueorigin

Our Exploration Systems' Supplemental Calibration System (SCS) has been successfully commissioned onboard Copernicus Sentinel-6B, an Earth-observing satellite jointly developed by NASA and U.S. and international partners. The SCS helps to measure ocean surface ripples with 1-centimeter accuracy. To get ultra-accurate sea level measurements from space, scientists must account for a tricky variable: water vapor in the atmosphere, which slows the satellite’s primary radar signal. We have also delivered the SCS for the next two Copernicus Polar Ice and Snow Topography Altimeter (CRISTAL) missions.

[jacqmans]

First image from Sentinel-6B extends sea-level legacy
16/12/2025

Copernicus Sentinel-6B, launched last month, has reached its orbit and delivered its first set of data, which show variations in sea level in the North Atlantic Ocean. This data underlines how the mission will continue to strengthen the long-term reference record of sea levels, a key parameter of climate change.

Following its launch on 17 November 2025, the first data from Sentinel-6B was captured on 26 November by the satellite’s Poseidon-4 altimeter. The image, shown below, is a combination of altimeter data from both the Sentinel-6 sea-level tracking satellites: Sentinel-6B and its twin, Sentinel-6 Michael Freilich, which was launched in 2020. The image shows the Gulf Stream current in the North Atlantic Ocean, off the eastern coasts of the US and Canada.

The Gulf Stream is a hugely important area of the North Atlantic Ocean, not only for the role it plays in global weather patterns and climate, but also because it’s a busy shipping route as well as a key ecosystem for marine species and therefore an important fishing zone.

ESA’s Project Manager for Sentinel-6, Pierrik Vuilleumier, acknowledged the teams’ efforts, “This is the second launch for the Sentinel-6 mission and I am very pleased to see that industry and agency teams have managed again to guarantee the essential continuity of the mean sea-level record, adding five years to the 35 years already accumulated.”

State-of-the-art altimetry
The image was created using data from the mission’s Poseidon-4 dual-frequency (C- and Ku-band) radar altimeter, which uses an innovative mode that has improved performance and resolution compared to previous satellite altimeter designs. Radar altimeter instruments measure the time it takes for radar pulses to reach Earth’s surface and bounce back to the satellite. Sentinel-6 also carries a microwave radiometer, which estimates the delay to the radar pulses caused by Earth’s atmosphere. Both these instruments work together to enable very precise measurements of the sea-surface height as well as wave height and wind speed.

Sentinel-6 also provides data for operational ocean forecasting by providing near real-time data on extreme weather at sea. The mission provides data to support safer navigation at sea, better coastal protection and smarter water-resource management.

ESA’s Director of Earth Observation Programmes, Simonetta Cheli, said, “Developing missions that can track sea-level rise with such precision and long-term reliability is fully aligned with ESA’s core values and strategic goals. The agency’s Earth Observation programmes are focused on providing environments that nurture the innovative technology for such satellites. We also establish the crucial collaborations that enable these missions to become key sources of actionable data for the science community and for climate policy. I thank our European partners as well as NASA and NOAA, and I look forward to seeing this mission continue the legacy of reference data on ocean conditions.”

ESA’s Mission Scientist for the Sentinel-6 mission, Alejandro Egido, said, “It is very encouraging to see Sentinel-6B performing so well soon after launch. While the instruments will undergo a careful calibration phase over the coming months, the quality of the initial dataset is very promising. Once this phase is completed, the mission will be fully prepared to extend the sea-surface height measurement record through at least 2030.”

https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-6/First_image_from_Sentinel-6B_extends_sea-level_legacy#msdynmkt_trackingcontext=c861e6ee-fc73-4238-a400-9cbb58050100