ESA’s Hera Ready to Go When SpaceX’s Falcon 9 Resumes Flight

ESA is ready to launch its Hera planetary defense mission just as soon as SpaceX’s Falcon 9 rocket is back in business. The launch window opens on Monday. SpaceX suspended Falcon 9 launches on Saturday to investigate an anomaly during the launch of Crew-9 after the second stage separated. ESA’s Hera and NASA’s Europa Clipper, both about to embark on planetary exploration missions with strict launch windows, are counting on SpaceX to resolve the problem and the FAA to issue launch licenses before the 2024 opportunities expire. ESA and NASA both are optimistic.

Hera is a companion to NASA’s Double Asteroid Redirection Test (DART) that impacted Dimorphos, the tiny moon of the asteroid Didymos, in 2022. DART demonstrated that a direct impact could change an asteroid’s path, an important step in planetary defense — protecting Earth from asteroids or comets that could threaten our planet.

Observations from Earth-based telescopes and a tiny Italian cubesat, LICIAcube, that rode along with DART until separating just before impact, provided a lot of information about what happened to Didymos and Dimorphos and the trail of debris left behind. Hera, named after the Greek goddess of marriage, will take a closer look.

The €363 million ($400 million) Hera will carry not only science instruments, but two cubesats to investigate what was left behind by the impact.

The shoebox-sixe cubesats, Juventas and Milani, will come in close to the double asteroid. Juventas, named for the daughter of Hera, carries the smallest radar instrument ever flown in space according to ESA. Milani will study Didymos and Dimorphos with a hyperspectral scanner, a camera and other instruments.

At a briefing yesterday, ESA officials acknowledged that operating in a debris-rich environment will be a challenge. Hera will begin approaching the asteroid pair in December 2026, moving in slowly. Ignacio Tanco, ESA’s Flight Director for Hera, said one advantage of having the cubesats is if they determine the debris field creates significant risk, the Hera “mothership” could stay further away and let the cubesats do the close-in observations.

Hera needs to launch between October 7 and October 27.  If not, it will have to wait two years for another opportunity until Earth and the double asteroid are correctly aligned again.

NASA’s Europa Clipper mission is under somewhat similar constraints. It’s scheduled to launch to Jupiter on October 10, the opening of a window that extends to November 6.

Both are launching on SpaceX Falcon 9 rockets: Hera on a single Falcon 9 and Europa Clipper on Falcon Heavy, a combination of three Falcon 9s.

Falcon 9 is a highly reliable rocket that SpaceX launches frequently. Last year they had 98 launches and have had more than 70 already this year.

However, in the past three months SpaceX has had to suspend launches three times. In July, a launch carrying 20 of SpaceX’s own Starlink satellites failed. SpaceX reuses the Falcon 9 first stages. They land either on drone ships at sea or back on terra firma. In August, a landing failed.

On Saturday, SpaceX revealed a problem with the second stage of the rocket that launched NASA’s Crew-9 to the International Space Station.  After the stage separated from the Crew-9 spacecraft, an anomaly occurred and the second stage did not correctly fire its engines to reenter. The stage fell harmlessly into the ocean as planned, but not within the designated coordinates.

After today’s successful launch of Crew-9, Falcon 9’s second stage was disposed in the ocean as planned, but experienced an off-nominal deorbit burn. As a result, the second stage safely landed in the ocean, but outside of the targeted area.

We will resume launching after we…

— SpaceX (@SpaceX) September 29, 2024

The FAA regulates commercial space launches and reentries and must issue a launch license to SpaceX and other U.S. commercial launch companies before flight. SpaceX quickly resumed flights after the first two anomalies after diagnosing and remedying the problems and getting FAA approval. The question is how long it will take this time.

SpaceX has not publicly provided any other information about what happened. The FAA said on Monday it is requiring an investigation. The FAA’s primary reponsibility is ensuring public safety and it said there were no public injuries or property damage, but is requiring an investigation.

How long it will take SpaceX to fix the problem and the FAA to issue a license is unknown.

ESA is optimistic and is proceeding with final preparations assuming an October 7 launch. The spacecraft is being encapsulated into the fairing today.  If the launch slips until later in the month, that’s not a problem. Stefan Voegt, Project Manager for Hera at spacecraft manufacturer OHB, said at the ESA briefing they are “not constrained” by encapsulation since all they need to  do is maintain battery status. “It can stay there for days or weeks if needed.”

They want to be ready when the FAA gives SpaceX permission to launch. Asked if they want SpaceX to launch another Falcon 9 before Hera to demonstrate the rocket is OK, Hera project scientist Michael Küppers replied “we’ll be ready to go tomorrow, so far as we’re concerned we’ll be happy to be the first passenger after the return to flight.”

Hera currently is scheduled to launch on October 7 at 10:52 am ET.

NASA also appears optimistic that Falcon 9 will quickly return to flight. Today it issued media advisories for the Europa Clipper launch on October 10.

Hera Project Manager Ian Carnelli said that if Hera’s launch slips into the Europa Clipper window, ESA has agreed with NASA to stand down for 48 hours to allow Europa Clipper to proceed.  Apart from that, Hera can launch any day between October 7 and 27. It has an instantaneous launch window, so must launch at an exact time each day that shifts a bit earlier as the days progress.  If it doesn’t launch by October 27, it will have to wait two years until October 2026 when Earth and Didymos/Dimorphos are correctly aligned again.