Returning to the Moon on the European Service Module
Moving to series production and dealing with the US, where things are done slightly differently
Interview NASA has set late August as the launch window for its much-delayed Artemis I rocket. Already perched atop the booster is the first flight-ready European Service Module (ESM). Five more are in the pipeline.
Airbus industrial manager Siân Cleaver, whom The Register met at the Goodwood Festival of Speed's Future Lab, has the task of managing the assembly of the spacecraft, which will provide propulsion, power, water, oxygen and nitrogen for the Orion capsule.
Looking for all the world like an evolution of the European Space Agency's (ESA) International Space Station (ISS) ATV freighter, the ESM is not pressurized and measures approximately 4 meters in length, including the Orbital Maneuvering System Engine (OMSE), which protrudes from the base.
The OMSE will also look a little familiar: "We've taken those directly from old Space Shuttles", Cleaver told us, which makes for a pleasing symmetry considering the mission.
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The Space Shuttle Orbital Maneuvering System has Apollo Service Module heritage and while those used by the EMS won't be returning to Earth, the technology is well proven.
Sadly, old Space Shuttle bits are a limited commodity. "We will fly those up to ESM-6," said Cleaver, "beyond that we're starting to think about using a new engine that's developed on the basis of this one."
At present Airbus is contracted to build six ESMs. The first is waiting for that first, uncrewed, launch. The second is already in Florida, awaiting integration with the next Artemis rocket and the third, which could well play host to the first astronauts to set foot on the Moon since the days of Apollo, is coming together in Bremen, Germany.
The first batch of ESMs have evolved as work has progressed. Lessons learned from ESM-1 filter down into ESM-2 and so on (and doubtless whatever is learned from that critical first test flight will also be stirred into the pot.) "There were a lot of changes between ESM-2 and ESM-3," said Cleaver. "…ESM-3 was a slightly different size to ESM-1 and 2 because they were thinking of pushing a Gateway module up with it…"
The plans NASA and its international partners have for launching the modules for the Gateway, a space station destined for a near-rectilinear halo orbit (NRHO) around the Moon, have been somewhat fluid over the years. One plan had called for the European System Providing Refueling, Infrastructure and Telecommunications (ESPRIT) and Habitation and Logistics Outpost (HALO) to be launched on Artemis 3 but has since been ditched in favour of separate commercial launches.
Things are due to settle down somewhat after ESM-3, although the project management of such a spacecraft continues to be a challenge. "I have a spreadsheet," said Cleaver, "that has all the different pieces of equipment and all the different subcontractors, and I track all of the delivery dates that way."
"So it's quite basic in that sense," she laughed.
One challenge is the international aspect of the endeavor. "We're working all across Europe," she said, "and then we're also working with US suppliers as well, who do things ever so slightly differently to how we're used to doing them in Europe in terms of documentation and processes.
"So it's really trying to make sure that everyone's on the same page, everybody's working the same way and everybody's respecting each other's deadlines."
Cleaver is looking forward to the next batch of ESMs, which will move to more of a series production line compared to ESMs 1 to 3. Bidding is underway for ESMs 7 to 9 and the intention is that things should become cheaper and quicker as batches of spacecraft get ordered.
But there remain those crucial early flights, the first without a crew and the second (hopefully) with. "We've had to change everything in the ESM," said Cleaver of the ATV comparison, "to make it completely safe for the crew."
"With ESM-1, it's a test: 'Let's try this, let's try that.' With ESM-2 you can't do that – people's lives are stake here."
Hence Cleaver is not overly bothered about the ongoing delays with Artemis 1. "We can't take any chances," she said. "I think we'd rather be delayed than have catastrophic failures and errors that can result in the loss of the mission. It's just not an option for us."
"We have to make sure that it's right, and it's right first time, which is why it's worth being conservative when talking about launch dates."
And as for when breathing will be able resume on the ground after Artemis 1? "I think for the guys on the European Service Module team," laughed Cleaver, "It will be when the Orion module has separated from the ESM right at the end of the mission."
Or maybe a bit later, once all the data from ESM-1's sensors has been confirmed as returned. After all, unlike the Space Shuttle from which its big engine is derived, the European Service Module will most definitely not be making a runway landing on Earth. ®