An Orbital Moon Station Is Our Gateway to Mars

By David Rothery, The Open University | September 29, 2017 4:04 pm
File 20170929 22066 1hu4n1g

Full moon photographed from Earth. (Credit: Gregory H. Revera/wikimedia, CC BY-SA)

The dream of a human habitat in orbit about the moon came a step closer on Sept. 27, 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.

Artist’s impression of the view from the DSG.

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. (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 aging – 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.


Could humans live on Mars? All you need to know about settling the Red Planet.


Get it now!


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). (Credit: 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.

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 traveling 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.


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

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: space exploration
  • Andrew Worth

    “However it is a logical next step after the ISS”

    There’s nothing “logical” about it. there’re no studies on the human body in space that would be advanced by such a facility and there’re no studies on space or the Moon that couldn’t be done more cheaply using far simpler and unmanned missions.

    What would be a logical next step would be a return to the Moon, the Lunar surface offers something to actually study, it has resources that could help support a manned mission, and it would give us a vital area of study of the Human body that we still lack, which is: How does the Human body react long term in a gravity field that’s neither one g or zero g’s, finally a third data point on the graph.

    And the “gateway to Mars” line is just propaganda nonsense.

    • Rob Neff

      VP Pence is saying that they will refocus NASA to look at a settlement on the moon, pushing a trip to Mars farther down the road.

      • Mutobola Mbombo

        The complex human journey to any spacial spot is already given to us under various metamorphic capacity and stages our life goes through but not in this dying earthly physical body that is ambitious just because of our half granted agency.

  • OWilson

    Sharing your space technology with Russia, who thwarted your last democratic election by denying Hillary the Presidency, and putting a family of Russian plants in your White House, sounds like an ill conceived plan. :)

    • Uncle Al

      …Remove parens, all on one line

      …If it weren’t true, why would NASA deny it?

      • Erik Bosma

        They’d get to Mars and the men would all be dead including at least one of the women while the remaining woman left alive would be hysterically insane. Although she would be pregnant and 9 months later Jesus of Mars would be born and come back to Earth where he would judge the living and the dead. Just sayin….

        • okiejoe

          Valentine Michael Smith. Can you grok it?

  • Uncle Al

    Social intent says, “Nonsense.”

    …Rapper B.o.B. raising funds to check if Earth is flat

  • Erik Bosma

    Why on Earth would anyone want to go to Mars? Maybe we can send all the stupid people there by telling them a bunch of lies. Oh wait, we’re already doing that. Also, shouldn’t we learn how to live on Earth before we go f’ing up another planet. They start getting pretty hot/cold from here on in.

    • Uncle Al

      Free space – outside the atmosphere (14.7 psi is a yard of lead thickness, mass/area) and outside the magnetosphere – is 90 rads/year hugely energetic cosmic rays plus the occasional solar flare fast-fry or coronal mass ejection. The surface of Mars is ~30 rads/year (near no atmosphere nor magnetic field).

      You will be blinded by radiation cataracts and be Chernobyled overall. Earth background radiation is ~0.6 rad/year maximum. Mars is perchlorate everywhere, killing your thyroid.

      Tunnel into the moon at the poles where there are shadowed water deposits, maybe, re The Moon is a Harsh Mistress, Heinlein.

      • Rob Neff

        There’s nothing new about that. One option is to store the water on the outside of the habitable area, that works well as a radiation shield. Obviously if colonizing the Moon or Mars you’d have to build underground or cover your structure with plentiful regolith. Mars has lava tunnels that might work right off the bat. Use mirrors to bring down sunlight.

    • OWilson

      Most of the Earth is ocean. It is teaming with mineral, plant and marine resources. A perfect, inexpensive, accessible, and much safer location for a domed biosphere than outer space, should an overflow ever be required.

      But millennials grew up with Roddenberry’s Star Trek, Carl Sagan and Bill Nye , and Stephen Hawking, who have them all convinced the Earth is overcrowded and dying.

      This Blue Marble, Goldilocks Earth, it seems, is now passe!

      • Rob Neff

        People like to blame the millennials for everything, even though they haven’t been in charge yet. Plus, Roddenberry and Sagan were dead long before millennials were even born.

        • OWilson

          I stand corrected!

          Generation X?

          • Mutobola Mbombo

            We have been submitted to be here with all our unfolding fantastic physical power of science and so on.. by nature, unfortunately despite us, only nature remains our faith and being natural component our access to fellow components of this place is obvious and sine quanone.

      • Erik Bosma

        As I said,”let them go.”

    • Rob Neff

      Wow, lots of negativity here, considering the audience should be fairly tech-savvy and interested in future developments.
      The people who would go to Mars will definitely be better-educated than the average person for sure, and would be well aware of the risks and how to mitigate them.

      I think our global population is big enough that we can focus on more than one thing at a time. Some people work on fixing our issues here, some work on extending ourselves into space, and 99.999% will carry on as normal, not paying attention to either task.

    • 31007 – TANSTAAFL

      Why do we need to leave the ocean and go crawling up onto the land when we have everything that we need here?

      Why do we need to come down from the trees and go walking around on the ground?

      Why do we need to leave the savanna and move to other continents?

      • Tammy A. Brown

        Maybe you are fed up of 9 to five job? Seeking out a good opportunity to work from home with the help of really easy activities simply by your laptop or computer moreover internet and want to earn fulltime paycheck of five hundred usd to one thousand usd per each week? I am focusing on this great opporutinity since four years and working only four-five hours every day and five days each week and potential to earn money here is pretty high and also you will get results of your tasks you are doing today in coming days as well. Therefore over-all it truly is an awesome project to work on and also that’s too from relief of your house. What it takes is personal computer along with a fast internet connection and you are ready to proceed. Make sure you to not to waste precious time and check out all the information right now… BINB.OOO/XUBAD

      • Erik Bosma

        Those were all forward steps.

  • Mutobola Mbombo

    My question is, would any one navigate even his naked legs without Astronote equipment in orbit of the moon to prove to us whether there is air there and life conducive?


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar