A new orbital moon station could take us to Mars and beyond. Here’s how

An artist's conception of the Phoenix Mars Lander on the Red Planet. Image: NASA/Getty.

The dream of a human habitat in orbit about the moon came a step closer on 27 September, when NASA and the Russian space agency (Roscosmos) signed up to a common vision for future human exploration. The project, a follow-up to the International Space Station (ISS), involves a facility placed in orbit somewhere between the Earth and the moon – a region known as cis-lunar space. Seen as a stepping-stone on the way to deeper space exploration, it has been dubbed the Deep Space Gateway, DSG.

NASA’s new heavy-lift rocket, the Space Launch System, which is still in development, will enable the construction of DSG. It will be supplemented by Russia’s less-powerful Proton-M and Angara rockets. However, it is misleading to portray this as a purely Russia-US partnership, because the three other ISS partners (the European, Japanese and Canadian space agencies) are highly likely to be involved too.

Since Apollo 17 came back from the moon in 1972, no human has ventured further from home than “low-Earth orbit”, an altitude of only 400km in the case of the ISS.

The International Space Station passing over part of the western Mediterranean in 2009. Image: NASA.

The ISS began construction in 1998 and has been continuously occupied by (usually) six crew since November, 2000. Previously planned to last until 2020, the project has been extended until 2024 and could be eked out longer. However it is ageing – and many would argue that it should have already been replaced. It has cost somewhere in the region of $150bn. That isn’t cheap, but, to put it into context, it works out as about the same as what humanity has frittered away on buying lipstick over the same 20-year period.

We can expect a comparable or larger price tag for the DSG, which is due to begin to be assembled in the mid-2020s, assuming that NASA can get its heavy-lift Space Launch System ready in time despite a precarious funding situation.

Orbits

The DSG derives its name because its position beyond the deepest part of Earth’s gravity well, the strongest part of the Earth’s gravity field, which means you need less energy to launch a mission from there. That makes it a great staging post for departure of human expeditions to the lunar surface and more distant destinations such as Mars. It could also act as a receiving facility for initial examination (and quarantine, for planetary protection purposes) of samples brought back from Mars or other bodies.

A NASA Orion craft brings a crew to the Deep Space Gateway in lunar orbit (artist’s impression). Image: NASA.

Unlike the ISS, the DSG would not be continuously inhabited. Current plans call for one annual 42-day visit by a four-member crew, at first. When unoccupied, instruments on the DSG could continue to collect useful scientific data, especially when close to the moon. It won’t be placed into a low lunar orbit, but into special points in space such as where the gravitational attraction between the Earth and moon are balanced. This allows it to follow a “near rectilinear halo orbit” (see video below). From the moon’s point of view, the DSG would repeatedly sweep low over one pole, offering great opportunities for scientific measurements.

The ‘Near Rectilinear Halo Orbit’ and other animations.

At other times the DSG may sit further from the moon, in a halo orbit about a position on the moon-Earth line known as the L₂ Lagrange point. The balance of gravitational forces here makes it possible to “park” a spacecraft to make observations.

However, these orbits are only quasi-stable, so some adjustments would be necessary to maintain the DSG in these configurations without floating away elsewhere. The Canadian Space Agency has suggested the use of a solar sail to do most of the work, rather than using thruster fuel. I think that is a great idea, because solar sails, which get a push from radiation pressure, have not yet been trialled adequately to test their potential – so this is an opportunity to assess how to best work them. Apart from their use in manoeuvring around the solar system, solar sails may one day propel probes to the nearest stars.


The competition

The DSG is all still a very long way from reality. However it is a logical next step after the ISS – and any long-term multinational cooperative enterprise in space has to be a good thing, given the bickering between nations going on down here on Earth. It may not lead us very quickly to Mars though – government-funded projects are often cash-strapped, meaning the plans could lag behind private enterprise efforts such as Elon Musk and his super-heavy-lift Interplanetary Transport System, or BFR.

This is only Musk’s first step. Speaking at the International Astronautical Congress in Adelaide, he revealed his own ambitious plans for a lunar base followed by rockets to Mars by 2022.

The ConversationWhichever way it comes about, it would surely be inspiring to see astronauts travelling beyond low Earth orbit again. A refurbishable platform such as the DSG somewhere near the moon would offer many ways to study both the moon (personally I’d like to mount an X-ray spectrometer on the DSG to map the distribution of the chemical elements across the lunar surface) and the interaction between Earth and the sun.

David Rothery is professor of planetary geosciences at The Open University.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

CityMetric is now City Monitor! Come see us at our new home

City Monitor is now live in beta at citymonitor.ai.

CityMetric is now City Monitor, a name that reflects both a ramping up of our ambitions as well as our membership in a network of like-minded publications from New Statesman Media Group. Our new site is now live in beta, so please visit us there going forward. Here’s what CityMetric readers should know about this exciting transition.  

Regular CityMetric readers may have already noticed a few changes around here since the spring. CityMetric’s beloved founding editor, Jonn Elledge, has moved on to some new adventures, and a new team has formed to take the site into the future. It’s led by yours truly – I’m Sommer Mathis, the editor-in-chief of City Monitor. Hello!

My background includes having served as the founding editor of CityLab, editor-in-chief of Atlas Obscura, and editor-in-chief of DCist, a local news publication in the District of Columbia. I’ve been reporting on and writing about cities in one way or another for the past 15 years. To me, there is no more important story in the world right now than how cities are changing and adapting to an increasingly challenging global landscape. The majority of the world’s population lives in cities, and if we’re ever going to be able to tackle the most pressing issues currently facing our planet – the climate emergency, rising inequality, the Covid-19 pandemic ­­­– cities are going to have to lead the way.

That’s why City Monitor is now a global publication dedicated to the future of cities everywhere – not just in the UK (nor for that matter just in the US, where I live). Our mission is to help our readers, many of whom are in leadership positions around the globe, navigate how cities are changing and discover what’s next in the world of urban policy. We’ll do that through original reporting, expert opinion and most crucially, a data-driven approach that emphasises evidence and rigorous analysis. We want to arm local decision-makers and those they work in concert with – whether that’s elected officials, bureaucratic leaders, policy advocates, neighbourhood activists, academics and researchers, entrepreneurs, or plain-old engaged citizens – with real insights and potential answers to tough problems. Subjects we cover include transportation, infrastructure, housing, urban design, public safety, the environment, the economy, and much more.

The City Monitor team is made up of some of the most experienced urban policy journalists in the world. Our managing editor is Adam Sneed, also a CityLab alum where he served as a senior associate editor. Before that he was a technology reporter at Politico. Allison Arieff is City Monitor’s senior editor. She was previously editorial director of the urban planning and policy think tank SPUR, as well as a contributing columnist for The New York Times. Staff writer Jake Blumgart most recently covered development, housing and politics for WHYY, the local public radio station in Philadelphia. And our data reporter is Alexandra Kanik, whose previous roles include data reporting for Louisville Public Media in Kentucky and PublicSource in Pittsburgh, Pennsylvania.

Our team will continue to grow in the coming weeks, and we’ll also be collaborating closely with our editorial colleagues across New Statesman Media Group. In fact, we’re launching a whole network of new publications, covering topics such as the clean energy transition, foreign direct investment, technology, banks and more. Many of these sectors will frequently overlap with our cities coverage, and a key part of our plan is make the most of the expertise that all of these newsrooms combined will bring to bear on our journalism.

Please visit citymonitor.ai going forward, where you can also sign up for our free email newsletter.


As for CityMetric, some of its archives have already been moved over to the new website, and the rest will follow not long after. If you’re looking for a favourite piece from CityMetric’s past, for a time you’ll still be able to find it here, but before long the whole archive will move over to City Monitor.

On behalf of the City Monitor team, I’m thrilled to invite you to come along for the ride at our new digs. You can follow City Monitor on LinkedIn and on Twitter. If you’re interested in learning more about the potential for a commercial partnership with City Monitor, please get in touch with our director of partnerships, Joe Maughan.

I want to thank and congratulate Jonn Elledge on a brilliant run. Everything we do from here on out will be building on the legacy of his work, and the community that he built here at CityMetric. Cheers, Jonn!

To our readers, on behalf of the City Monitor team, thank you from all of us for being such loyal CityMetric fans. We couldn’t have done any of this without you.

Sommer Mathis is editor-in-chief of City Monitor.