ESA's Hera asteroid mission will launch on a Falcon 9 because of delays in the introduction of the Ariane 6. Credit: ESA

WASHINGTON — The European Space Agency now plans to launch a space telescope and an asteroid mission on Falcon 9 rockets because of its loss of access to Soyuz vehicles and delays in the introduction of the Ariane 6.

At an Oct. 20 press briefing after a meeting of the ESA Council, ESA Director General Josef Aschbacher said the agency had decided to launch the Euclid astrophysics mission on a Falcon 9 in 2023 and Hera, an asteroid mission, in 2024.

Euclid, a cosmology mission featuring a space telescope operating at the Earth-sun L-2 Lagrange point, was originally scheduled to launch on Soyuz, but needed a new launch vehicle after Russia halted Soyuz launch operations from French Guiana in response to Western sanctions. Falcon 9 had emerged as the likely option to launch Euclid, something confirmed by NASA officials Oct. 17 who said that ESA was conducting a feasibility study on using Falcon 9 to launch Euclid.

Euclid was one of two ESA missions that had been scheduled to launch on Soyuz. The other, an Earth science mission called EarthCARE, will launch on Europe’s Vega C, Ashcbacher said.

Hera is a mission that will fly to the near-Earth asteroid Didymos and its moon Dimorphos, the target of NASA’s Double Asteroid Redirection Test (DART) mission that collided with Dimorphos last month. Hera will study the asteroids, including the effects on Dimorphos from the DART collision.

Hera was scheduled to launch by the end of 2024 on an Ariane 6, a schedule Aschbacher said was no longer feasible given the latest delay in the first Ariane 6 launch that ESA announced Oct. 19. “Given the rampup that is expected on Ariane 6, it will not be possible to launch on Ariane 6,” he said. “Therefore, this will be launched on the Falcon 9.”

ESA did not disclose the cost of shifting the missions to Falcon 9, including any Soyuz launch contract deposits it may have forfeited with the change. Günther Hasinger, ESA director of science, said the change would have a “positive effect” on the science budget because it would save time versus waiting for a European launch. “I think this is a positive move for the science budget.”

Other missions could also be affected by Ariane 6 delays. Francisco-Javier Benedicto Ruiz, director of navigation for ESA, said that ESA and the European Union need to resume launches of Galileo satellites, put on hold by the loss of Soyuz and Ariane 6 delays, in late 2023 or early 2024 to keep the navigation constellation at full strength.

“Ariane 6 is our preferred option,” he said. “We are going to be monitoring the planning of Ariane 6 in the coming months. In the meantime, we have initiated actions to look for non-European launch service options.” He said he expected a decision sometime in the first half of 2023 on how to launch the next Galileo satellites, which are currently manifested on the second Ariane 6 flight.

Another mission affected by Russia’s invasion of Ukraine is ExoMars, which was to launch in September on a Proton to send the Rosalind Franklin rover to Mars. Aschbacher said ESA member states will make a decision on the future of the mission at the November ministerial meeting.

The preferred option is to launch ExoMars in 2028, which will require building a new descent module to replace the one Russia provided. David Parker, director of human and robotic exploration at ESA, said the agency will request funding to start work on the new module at the ministerial, but did not disclose the budget for it.

Aschbacher said the mission had studied if the rover was still useful scientifically even if it launches in 2028, arriving at Mars in 2030. The mission is designed to drill into the surface to look for evidence of past Martian life.

That review, presented at the ESA Council meeting, confirmed those scientific objectives remained valid even if the mission is delayed to the end of the decade. “The project scientist presented the science case and actually got a round of applause at the end of it, because in a few minutes he captivated the audience with the scientific goals of the mission.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...