WASHINGTON – A Falcon 9 successfully launched an Earth science mission for Europe and Japan on May 28 as part of the European Space Agency’s continued, if temporary, reliance on SpaceX for access to space.
The Falcon 9 lifted off from Vandenberg Space Force Base in California at 6:20 p.m. Eastern. The payload, the Earth Cloud Aerosol and Radiation Explorer (EarthCARE) spacecraft, separated from the upper stage about 10 minutes after launch.
Simonetta Cheli, director of Earth observation programs at ESA, said in an interview after the launch that controllers were in contact with the spacecraft. “It’s all nominal and on schedule.”
Spacecraft controllers will check and calibrate the spacecraft’s instruments in the coming weeks and months, she said. That will enable the first publication of EarthCARE scientific data around the end of this year or early next year.
EarthCARE is an ESA-led €800 million ($870 million) mission to study clouds and aerosols in the atmosphere. The spacecraft carries four instruments, including a cloud profiling radar supplied by Japan’s JAXA space agency at a cost of 8.3 billion yen ($53 million). JAXA named the spacecraft Hakuryu or “White Dragon” because of the spacecraft’s appearance.
The 2,200-kilogram spacecraft, which will fly in a sun-synchronous orbit at an altitude of 393 kilometers, will collect data on clouds and aerosols in the atmosphere, along with images and measurements of reflected sunlight and radiated heat. That information will be used for atmospheric science, including climate and weather models.
“EarthCARE exists to study the effect of clouds and aerosols on the Earth’s thermal balance,” said Dirk Bernaerts, ESA’s EarthCARE project manager, during a pre-launch briefing on May 21. “It is very important to observe them all together in the same location at the same time. That is what is unique about this spacecraft.”
Other spacecraft are making similar measurements, including NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) spacecraft that launched in February. “The observation techniques are different,” he said. “We are observing the same thing, but observing slightly different aspects of the clouds and aerosols.” He added that EarthCARE would use PACE data to help calibrate and validate its observations.
EarthCARE’s development took about twenty years and resulted in cost growth that Cheli estimated at 30% during the pre-launch briefing. Maximilian Sauer, EarthCARE project manager at prime contractor Airbus, said several factors contributed to the delays and overruns, including technical problems with the instruments and the impact of the pandemic.
One lesson learned from EarthCARE, Cheli said in the post-launch interview, was the need for “strict management” of the project, which she said faced challenges in coordinating work between agencies and companies. The mission also underlined the importance of strong support from Member States in overcoming challenges, she added.
Another factor in EarthCARE’s delay was a change in launch vehicles. EarthCARE was originally planned to be deployed on a Soyuz rocket, but ESA lost access to the vehicle following the Russian invasion of Ukraine. The mission was first moved to Europe’s Vega C, but ESA decided last June to launch it on a Falcon 9 instead, citing delays in returning that rocket to service and modifications to the rocket’s payload fairing that would have been necessary to make EarthCARE possible.
Technically, the shift in launch vehicles was not a major problem for the mission. “During the changes to the launch vehicles, we did not have to change the design of the spacecraft,” said Bernaerts.
He said engineers subjected the spacecraft to conditions simulating different launch vehicles during environmental testing to prepare for the potential of changing vehicles. “From the moment we knew Soyuz was unavailable, we looked at how rigorously we could test the spacecraft to outcompete other launch vehicle candidates. We did that and it ultimately worked.”
EarthCARE is the second ESA-led mission to be launched on a Falcon 9, following the Euclid Space Telescope last July. Another Falcon 9 will launch ESA’s Hera asteroid mission this fall.
“We had a good experience with Euclid last year,” ESA Director General Josef Aschbacher said in an interview after the launch. “Our teams and the SpaceX teams work very well together.”
The use of the Falcon 9 is a stopgap solution until the Ariane 6 enters service, with a first launch planned for the first half of July, and the Vega C returns to flight at the end of the year. “I hear a lot of questions about why we’re launching with Falcon and not Ariane, and it’s really good to see the inaugural flight of Ariane 6 getting closer,” he said.
Those involved in the mission were simply happy that the spacecraft could finally be put into orbit. “There is a sense of relief and happiness,” Cheli said after the launch.
“This is an emotional rollercoaster,” Thorsten Fehr, EarthCARE mission scientist at ESA, said on the webcast of the launch shortly after the payload separation. “This is one of the best moments of my professional life ever.”