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Anatoly ZakNovember 3, 2016

An international outpost near the Moon gets closer to reality

International Space Station (ISS) project partners are inching ever closer toward an agreement to begin the development of a new human outpost in the vicinity of the Moon. If successful, the cis-lunar space station (a space station in the vicinity of the Moon) will be the largest international space project to date, influencing the direction of human space flight for decades to come.

During a closed-door meeting in Houston last week, NASA officials met their colleagues from Europe, Russia, Japan, and Canada to discuss the latest changes to the cis-lunar space station concept. The team, known as the International Spacecraft Working Group, ISCWG, is charged with brainstorming all the technical details necessary to start the development of the new deep-space exploration program after the retirement of the ISS, now expected in mid 2020s. The team's recommendations are not binding, but will likely form the reference architecture for any future project.

The current vision involves a multi-modular outpost, essentially a smaller version of the ISS, but in the vicinity of the Moon instead of in Earth’s orbit. The outpost will also use more advanced technologies than those available on the ISS, such as closed-loop life-support systems and electric propulsion. These could enable the outpost to become the first interplanetary crewed spacecraft heading into deep space to explore asteroids or even reach the vicinity of Mars in the 2030s. To reflect that ultimate goal, NASA identified the facility as a “proving ground” for Mars exploration.

Lockheed Martin concept for a modular cis-lunar base

Lockheed Martin

Lockheed Martin concept for a modular cis-lunar base

What will it look like?

The cis-lunar outpost would be built primarily out of modular components riding NASA’s giant SLS rocket as hitchhikers along with the Orion spacecraft. Following its insertion into trans-lunar trajectory, the Orion crew capsule would separate from the booster stage, turn around and dock with the add-on module still attached to the booster stage, very much like Apollo crews did to extract their lunar modules in the 1960s.

However, instead of landing on the lunar surface, each Orion mission would bring an add-on module to the vicinity of the Moon, where they would all be bolted together to form a long-term habitat. Other countries could launch their own components, as with the ISS program.

Assembly sequence

According to the latest architecture worked out by the partners, the construction of the outpost would start with a 8.5-ton power and propulsion module launched during the Orion’s third Exploration Mission, EM-3.

Recently, the European Space Agency agreed to provide an additional cutting-edge electric engine unit, which would help to propel the first module. Both American and European electric thrusters would be fed by xenon gas. The same module would also provide power supply and communications for the entire outpost. Last but not least, Canada would build a robotic arm, which would be strapped to the propulsion module and later used on the outpost.

Once the power and propulsion capabilities are in place, a pair of habitation modules would be delivered and attached to it in two subsequent Orion missions, EM-4 and EM-5. Previous incarnations of the plans envisioned these components being built in Russia or Europe, but the Japanese space agency has recently offered to contribute its own habitat. The Japanese habitat would feature a closed-loop life-support system, greatly reducing dependency of the outpost on deliveries of water and oxygen from Earth.

Also this year, the Russian space agency, Roscosmos, agreed to consider contributing an airlock module for the outpost, which would be used for spacewalks. During its ride to the lunar vicinity with the Orion spacecraft, the airlock would be packed full of supplies for the future station, bringing its launch mass to around nine tons. Alternatively, Roscosmos could launch the airlock module independently, using its new-generation Angara-5 rocket, upgraded with a high-power hydrogen space tug.

Theoretically, Russia could also support the international program with its next-generation transport spacecraft dubbed Federatsiya (Federation), which is expected to be the only alternative to the Orion in bringing crews to the outpost. As of today, Roscosmos promises the first crewed flight of the new ship in the low Earth’s orbit in 2024, followed by the first mission to lunar orbit in 2027. Although SpaceX and other private providers are likely interested in providing transportation services to a cis-lunar program, only the NASA Orion and Roscosmos CTV spacecraft appear on the official schedule.

The cis-lunar space station could also be complemented by a 10-ton robotic vehicle developed jointly by ESA, Japan, and Canada. It could be equipped with a rover and an ascent stage for returning soil samples from the surface of the Moon. The robotic vehicle could be launched independently on a rocket provided by one of the partner agencies in 2026, at the earliest. Once the probe lands on the Moon, a crew onboard the cis-lunar outpost could remotely operate the soil-sampling rover on the surface and then launch the ascent stage for the subsequent transfer of samples back to Earth.

In the course of its assembly and operation, the cis-lunar outpost could be resupplied by cargo vehicles launched on a variety of rockets.

During the second phase of assembly, at the end of the 2020s, the outpost would be complemented with NASA’s newest habitation and propulsion module launched on a dedicated SLS rocket. This latest addition could make it possible for the outpost to embark on the first mission into deep space.

Where do they stand?

Sources familiar with the matter say that after years of negotiations, the international team made enough progress to reach an agreement in the near future, which would see ISS partners all contributing components and technologies for the common goal. The initial phase of development of the cis-lunar outpost, known as Phase A, could then go ahead in 2017 or 2018.

During the Houston meeting this month, it was decided to postpone the beginning of the habitat construction by around a year until 2023. Under this scenario, the first phase of the outpost would be completed in 2028. Of course, if history of the ISS is any guide, many delays are very likely.

There are several political developments coming even this year, which can throw a monkey wrench into the carefully constructed schedule. Obviously, the first being the US presidential elections, which are notorious for changing the course of the American space program. Next, comes a meeting in December of the European ministers drawing the ESA’s budget for the next several years. And another wild card in the project is the Russian involvement, which remains uncertain due to an array of political, financial and technical problems.

Not surprisingly, partners scheduled the next meeting on the cis-lunar outpost at the beginning of next year. Although 2017 is just two months away, it could very well be in another era for space exploration…

Anatoly Zak is the publisher of and the author of Russia in Space: the Past Explained, the Future Explored.

Read more: SLS, Humans to Mars, Orion, mission status, human spaceflight, International Space Station, Russian human spaceflight

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