ESA’s Hera spacecraft launches on SpaceX’s Falcon 9 rocket as Hurricane Milton takes aim at Florida
by Will Robinson-SmithThe European Space Agency and SpaceX managed to find good enough weather right in the nick of time to launch a mission to a binary asteroid Monday morning.
The Hera mission is a follow-on operation, which will examine Didymos and it moon, Dimorphos, after the latter was struck by NASA’s Double Asteroid Redirection Test (DART) spacecraft.
“It’s been 18 years we’ve been working to put this mission together, so you can imagine our emotions, not only mine, but the whole team,” said Ian Carnelli, the Hera project manager, during a prelaunch media briefing.
Liftoff of the Falcon 9 rocket from pad 40 at Cape Canaveral Space Force Station happened at 10:52 a.m. EDT (1452 UTC).
The mission came during the heart of hurricane season in Florida and as luck would have it, on Sunday afternoon, the National Hurricane Center in Miami declared that what was Tropical Storm Milton had strengthened to Hurricane Milton.
During the countdown, the storm was confirmed to be a Category 4 hurricane out in the Gulf of Mexico, strengthening to a Category 5 prior to spacecraft deployment.
On Sunday, the 45th Weather Squadron based at Patrick Space Force Base, issued its forecast, showing just a 15 percent chance of favorable weather at launch time.
During a prelaunch briefing Sunday morning with reporters, Ian Carnelli, the Hera project manager, said weather had been the biggest X-factor for them at this point.
“The last hurdle is the weather. So, please, please I need you to do something about it. It’s the only thing I really cannot control,” Carnelli said jokingly to reporters. “So I checked… and it looks like we have some opening around the time of launch, but it’s really impossible to say at the moment.”
Hera isn’t the only marquee mission that was watching the weather. NASA’s Europa Clipper mission was also scheduled to launch this week no earlier than Thursday, Oct. 10, on a SpaceX Falcon Heavy rocket. However, NASA and SpaceX delayed the mission to sometime after the storm passes.
Both missions will use expendable versions of their respective Falcon vehicles in order to maximize their performance.
In a statement on Sunday, the Federal Aviation Administration said the Falcon 9 rocket was approved for one mission as the investigation connected to the Crew-9 upper stage anomaly continues.
“The FAA has determined that the absence of a second stage reentry for this mission adequately mitigates the primary risk to the public in the event of a reoccurrence of the mishap experienced with the Crew-9 mission,” the agency wrote. “Safety will drive the timeline for the FAA to complete its review of SpaceX’s Crew-9 mishap investigation report and when the agency will authorize Falcon 9 to return to regular operations.”
The FAA said SpaceX submitted its investigation report on Friday, Oct. 4, along with a request to return to normal flight operations.
SpaceX will be launching the Hera mission using one of its flight leaders, Falcon 9 booster tail number B1061. It will fly for a 23rd and final time on this mission.
“Due to the additional performance required to deliver the payload to an interplanetary transfer orbit, this mission marks the 23rd and final launch for this Falcon 9 first stage booster, which previously launched Crew-1, Crew-2, SXM-8, CRS-23, IXPE, Transporter-4, Transporter-5, Globalstar FM15, ISI EROS C-3, Korea 425, Maxar 1, ASBM, and 10 Starlink missions,” SpaceX wrote on its launch page.
Studying binary asteroids
The Hera mission marks a return to Didymos and Dimorphous and the first planetary defense mission for ESA. Michael Kueppers, ESA’s Hera project scientist, said the primary scientific goals are to measure the mass of Dimorphous, which will help them understand how efficient the DART impact was in 2022.
Kueppers said knowing it was the DART spacecraft that created a crater on Dimorphous and then going to study that will also help them better understand “the cratering processing.” He said those key facts can help inform future planetary defense missions, if and when future humans discover a threatening, Earth-bound asteroid.
“Once we have Hera and we investigate Dimorphous in detail, we know what it’s properties are and then, in case anything happens, one could again investigate that asteroid and then extrapolate the result from DART and Hera, essentially to find out which kind of impactor would be needed to get the right deflection for that next asteroid,” Kueppers said.
At the heart of the Hera spacecraft is the Advanced Data and Power Management System (ADPMS-3), the onboard computing system from Redwire Space.
“Basically, all the telemetry that are going to Earth, to the ground stations is being processed and generated by the onboard computer and it also receives the telecomands and gives instructions to the whole satellite,” the ADPMS-3 project manager said. “It’s part of the third generation of our Advanced Data and Power Management System. We have flown previous generations on the Proba missions.”
Cheryl Reed, the former project manager of the DART mission joined members of the Hera team in Florida to watch the launch of the mission. She said she’s looking forward to seeing all the data gathered once Hera arrives as Dimorphous and what this means for Earth’s protection in the future.
“These two missions collectively, from my perspective, they put planetary defense on the map. DART, when it first happened, both the launch and the actual impact was recognized around the world,” Reed said. “It’s a mission I can say to folks ‘Do you know about that asteroid impact?’ and they’re like, ‘Oh, DART!’ and that doesn’t happen with a lot of missions, that it can affect on such a personal level our lives because if we were to have an impact of an asteroid, we really need that.”
Hera will be joined by two, shoebox-sized CubeSats, which is a first for an ESA mission. Milani is designed to approach the surface of Dimorphous, first at 10 km (6.2 mi) and then as close as 2 km (1.2 mi).
Manufactured by Tyvak International, Milani uses a cold gas propulsion system and is equipped with star trackers for navigation, a laser altimeter and a visible light camera. Following its primary observation mission, Milani will also attempt to land on Dimorphous.
“Milani doesn’t have any instrument requiring landing to achieve mission success. I want to stress this,” said Margherita Cardi, Milani’s program manager. “But since we are there for technological demonstration and also in view of future missions, we want to attempt. The other CubeSat will also try to have an instrument for that.”
That other CubeSat is called Juventas and it was developed by GomSpace. Its three main objectives are:
- To determine the gravity field of Dimorphos
- To determine the interior structure of Dimorphos
- To determine the surface properties of Dimorphos
Its two main instruments are the mono static synthetic aperture radar called “JuRa,” which will “provide the first direct probing of an asteroid subsurface and internal structures,” and the Gravimeter for the Investigation of Small Solar System Bodies (GRASS).
“[It] will measure the gravity, the very low gravity of an object the size of the pyramid in Egypt and we are going to try and land on this object,” said Jan Persson, the Juventas project lead for GomSpace.
Those who have spent many years with this mission, like Kueppers said it will be an exciting moment to see Hera reach its target in 2026, but note that it won’t be quite as dramatic as DART’s arrival in 2022.
“Hera will approach much more slowly in the sense that it’s a rendezvous mission. So, it will lose relative velocity months and weeks before. So we slowly be getting the resolution increased, which is also very exciting to follow, but it’s kind of on a different pace,” Kueppers explained. “It’s not as quick of an event, like DART. It’s somewhat different in that sense. In that sense, more comparable to the time when Rosetta approached the target comet.