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Lunar return: how efforts to get boots back on the moon are gathering pace

After more than half a century away, humanity finally has concrete plans to return to the Moon, as well as to build a lunar space station. Andrew Wade reports.

NASA's Artemis 1 uncrewed Orion spacecraft during its 2022 flight around the moon and back
NASA's Artemis 1 uncrewed Orion spacecraft during its 2022 flight around the moon and back - NASA

The Apple TV series For All Mankind is built on a simple, intriguing premise: what if the space race hadn’t ended. Instead of crewed lunar exploration fizzling out within a few short years of Armstrong and Aldrin’s iconic moment, what if the United States and Russia continued to drive each other forward, colonising the Moon and eventually Mars. It’s an alternate reality thought experiment packaged up as prestige television, one that raises questions around humanity’s choices and ambition in the wake of Apollo.

More than 50 years have now passed since Apollo 17, the final crewed mission to the Moon. In the interim, robotic exploration, space instrumentation and the International Space Station have all taken precedence, as the Moon landings receded into history. But with the success of the Artemis 1 mission just over a year ago, humanity once again stands on the verge of putting boots on the lunar surface. And though NASA is very much to fore, the Americans are not embarking on this adventure alone.    

“This time, Europe is going,” Ana Gonzalo, European Space Agency (ESA) Lunar Project Control team leader, told The Engineer. “This time, Europe is at the heart of it. The European Space Agency is providing major, major elements to the Artemis programme.”

One of the most important of these elements is the European Service Module (ESM), the primary power and propulsion unit for Artemis’s Orion spacecraft. After launching on NASA’s Space Launch System (SLS), Orion will transfer crews of up to four astronauts to lunar orbit then back to Earth again. When The Engineer spoke to Gonzalo in December 2023, the one-year anniversary of Artemis 1’s uncrewed Orion landing back on Earth was just approaching.

“During these last weeks we are living very special moments, remembering all that we went through that month during the mission,” she said.

“The European Service Module went above and beyond expectations. We propelled the Orion vehicle to the Moon and back. We performed two very challenging manoeuvres, the flyby manoeuvres to insert the Orion spacecraft in the distant retrograde orbit. And we generated even additional power than expected with the solar arrays.” 

The end of the space race may have put the brakes on the cutthroat, win-at-all-costs technological endeavour typical of the Cold War. However, a more collaborative space sector has taken its place, personified by the ISS and now continued by the joint international efforts to return to the Moon.

NASA's Orion spacecraft docked to the Lunar Orbital Gateway - ESA

Alongside NASA and ESA, the Artemis programme includes the Canadian Space Agency (CSA), the Japan Aerospace Exploration Agency (JAXA), the German Aerospace Centre (DLR), the Israel Space Agency (ISA), and the Italian Space Agency (ASI). Listening to Gonzalo speak, it’s clear that the multi-agency nature of Artemis is seen as a strength rather than a weakness, the ‘For All Mankind’ mantra now practiced instead of just preached.

“We learned to work together,” she said. “The different teams from industry, from the European Space Agency, from NASA, from the American industry. I think that is very important that the teams work together not only during the development of the hardware, but also during the execution of the mission. And I can see it in the faces of my colleagues, the ones that were there working hand-in-hand with the NASA colleagues, how they felt part of an integrated team.”

That team is scheduled to be in action once again before the end of the year, with Artemis 2 provisionally set for a November 2024 launch. The first crewed mission of the programme will see four astronauts (three Americans and one Canadian) perform a lunar flyby, the first time humans will have travelled beyond low Earth orbit since Apollo 17 in 1972.

All going well, Artemis 3 will launch roughly one year later in December 2025. This is the mission currently scheduled to return mankind to the Moon’s surface, with Orion planned to rendezvous with SpaceX’s Starship Human Landing System (HLS) in lunar orbit. Two of the four astronauts will then descend to the Moon in the HLS, staying for approximately seven days before ascending back to Orion, which will return the crew to Earth.

However, the chances of actually seeing boots back on the Moon that soon appear slim. The US Government Accountability Office (GAO) recently released a 47-page report highlighting some of the major concerns around crewed missions to the surface, particularly around the HLS. The Starship system has yet to register a successful orbital flight, leaving SpaceX an enormous amount of work to complete over the next two years for the HLS to be able to support Artemis 3 in December 2025.

If the HLS is not ready in time, there is an alternative mission that Artemis 3 could undertake. The first modules of the Lunar Gateway, a Moon-orbiting space station that is a core element of the Artemis programme, are set to launch on a Falcon Heavy in November 2025. In place of a lunar landing, Artemis 3 may end up being the first crewed mission to rendezvous with this new space station.

ESA is heavily involved in the development of Gateway, delivering multiple modules and components. Like the ISS, the lunar space station will be built in sections across several missions.

“Gateway is composed of one power and propulsion element, two habitation modules, a refuelling module, a robotic arm, and later on it will be complemented by an airlock,” Gonzalo explained.

The first two modules - the Power and Propulsion Element (PPE) and Habitation and Logistics Outpost (HALO) - are NASA-led. These will form the bare bones of Gateway, capable of hosting Orion during Artemis 3 if a Moon landing isn’t possible.

The Multi-Purpose Habitat (MPH) aims be the first permanent outpost on the Moon - Thales Alenia Space

Artemis 4, as well as carrying another crewed Orion mission, will also deliver the International Habitation Module, or I-HAB. Led by ESA in collaboration with JAXA, I-HAB will serve as Gateway’s primary habitation unit, providing around 10 cubic metres of living quarters and workspace to support four astronauts for up to 90 days. Its preliminary design review was completed in November 2021 and a critical design review is slated for the end of 2024. Prime contractor Thales Alenia Space – builder of several ISS modules – is currently delivering a scale model at its Turin site.

“The final integration of this I-HAB mock up is happening right now in Turin,” said Gonzalo. “It will allow the integration of the different functionalities that will allow (us) to test the cabin outfitting. In spring next year, the first human-in-the-loop test will take place.”

Thales Alenia Space is also building the ESPRIT (European System Providing Refuelling, Infrastructure and Telecommunications) module for Gateway, due to launch no earlier than 2029 on Artemis 5. Further missions are planned to deliver a logistics module, an airlock module and the Canadarm3, a pair of robotic remote manipulator arms similar to those in place on the ISS.

Gateway will sit in a highly elliptical, seven-day near-rectilinear halo orbit (NRHO), whereby its distance from the Moon will vary from 1,500km to 70,000km, at times placing it closer to Earth than the Moon itself. As well as facilitating access to large areas of the Moon’s surface, the NRHO will provide virtually unbroken line-of-sight to Earth, a key consideration both for crewed comms and the long periods when the space station will be operating autonomously. The NRHO will also use much less fuel than a low lunar orbit.

“If the Gateway would be placed in a low lunar orbit, we would need much more propellant to maintain the orbit because of the Moon’s gravity,” said Gonzalo.

A distant retrograde orbit – used by Orion on the Artemis 1 mission – would use even less energy, but would not put Gateway within a useful distance to physically support lunar landings. NHRO provides a compromise, allowing Gateway to stay on station with minimal energy while also passing close enough to the Moon to facilitate Artemis’s longer-term goal of a sustained lunar presence.

“It’s also providing a unique environment that we cannot mimic neither on the Earth, neither on the ISS,” said Gonzalo. “This will allow scientists to take advantage of the environment in deep space. So the possibilities for the scientific community grow exponentially.”

Thales Alenia Space’s involvement in this new era of lunar exploration doesn’t end with Gateway. The company’s Turin team was recently contracted by the Italian Space Agency (ASI) and NASA to start work on the Multi-Purpose Habitat (MPH), a small, permanent Moon base capable of supporting short to medium term surface missions. According to Franco Fenoglio, head of human planetary exploration and robotics programs at Thales Alenia Space, the company’s extensive involvement with Gateway gives it somewhat of a headstart on the MPH.

Gateway's I-Hab module under construction in Turin - ESA

“We will obviously try to see the potential synergies between the activities,” he told The Engineer.

“We are contributing to the mechanical part of HALO…and providing our part to Northrop Grumman. We are the prime contractor for ESA of the I-HAB, which is probably the most complicated module in the Gateway. And we are contributing also on ESPRIT to the pressurised part, the window module.” 

The MPH is in the very early stages of development, with a mission concept review expected in the first quarter of 2024. Thales Alenia Space is currently working off the assumption that the MPH will have to support two astronauts for seven days. As with all things space, weight is a major consideration.

“We are still facing a pretty strong constraint in terms of limitation of the weight of the module at launch due to the requirement by the lander,” said Fenoglio. “This is the same problem, the same constraint we have for instance with the Gateway modules.”

Those Gateway modules are limited to just 3m diameter and 10 tonnes. For now, the MPH has the same diameter constraints but is provisionally allotted an additional 2 tonnes of weight. This is in part due to demands of the lunar surface that the Gateway modules will not be subjected to.

“When you land on the surface, the situation is different,” Fenoglio continued. “You start to feel gravity, even if just one-sixth (of Earth’s). That means that the accommodation of the interior of the module has to be considered in a different way. I mean, they have to sleep, and you cannot put them on the ceiling as you do in orbit!

“They have to survive the lunar night period…and this requires a lot of energy. And of course, during the lunar night, you cannot use the solar arrays, so we will need, for instance, batteries with very high efficiency.” 

As the project is being led by ASI, Italian supply chains will be used as much as possible. Fenoglio says this could include companies who are not necessarily specialists in the space sector, but who can deliver expertise around the challenges presented by the lunar surface, such as dust protection.  

“Dust is really one of the key problems on the surface,” he said. “So we will have to understand how to protect the system and particular mechanisms from the dust.”

In addition to dust protection, other core design parameters will include levelling legs to help position the MPH, as well as thermal control, avionics, comms and PNT (position, navigation and timing). With delivery planned for the end of the decade, the MPH has a rapid road of testing ahead, with scale mock ups likely to be built at Thales Alenia Space’s Turin site, similar to I-Hab.

“We have already here in Torino a terrain for simulation of Mars with the Italian space Agency,” said Fenoglio. “Now they are thinking about the lunar terrain. So for sure we will have to do a significant set of tests on the ground.”

After a long wait, real life space exploration may finally be catching up with Hollywood. One small step at a time. 

Goonhilly - The South West’s lunar lighthouse

Built in 1962 on Cornwall’s Lizard Peninsula, Goonhilly Earth Station played a crucial role in transmitting the pictures from the first Moon landings to millions of homes around the world.  

Goonhilly's flagship 32m ‘Merlin’ dish - Goonhilly

“It was as far west as it could be to pick up the first transatlantic TV pictures,” Ian Jones, Goonhilly’s CEO, told The Engineer. “So actually it sits in a really good place, being able to see the US, being able to see Europe and bits of Asia as well.”

Following a major refurbishment by Jones and his team after they took over the former BT-owned site more than a decade ago, Goonhilly now contributes directly to lunar and deep space exploration. As well as providing satellite services via dozens of antennas, upgrades to its flagship 32m ‘Merlin’ dish enabled qualification on NASA’s Deep Space Network and ESA’s ESTRACK Network.

Goonhilly subsequently participated in the Artemis 1 mission. From Cornwall, the station accurately tracked and measured changes in the radio waves that Orion transmitted on its journey. Goonhilly has also supported India’s 2023 Chandrayaan-3 robotic Moon landing, along side a host of other private and agency lunar and deep space missions.

However, getting Goonhilly up to speed for this new wave of lunar exploration was no easy task, requiring significant engineering. Amongst other things, Merlin needed to be converted from Ku and C band capability to the S and X band needed for deep space operations.

“The thing we were concerned about was the bearing,” Jones explained. “Where the dish rotates around the top of the building wasn’t wide enough for S-band signals to get through because of the increased wavelength.

The team had to adjust mirrors on the antenna’s periscope to correctly receive S-band signal as well as design a completely new feed system. The dish’s movement also needed a refresh to cope with the increased demands of longer-range comms.

“For deep space missions, going off to Mars and the like, you might have a 40-minute round trip delay between sending the signal out and receiving,” said Jones. “So you need really accurate motors and gear boxes. All of that needed reprofiling, so we literally changed the motors, the gearboxes, the control computer, all of the control electronics for the antenna.”

Merlin’s makeover didn’t end there, with one last painstaking job still required. 

“We decided that a few of the nuts and bolts were a bit on the rusty side,” said Jones. “We weren’t quite sure what to do, so we changed them all. 10,000 of them.”