See Update below *
A train to the surface of the moon
The Deep Space Gateway (DSG) NASA intends to put at the L1 Lagrange point around the Moon, together with a host of international partners, has plenty of uses as a gateway to the Moon surface but also to Mars and deep space.
(Update: To read a 2018 article about the first European and privately funded mission to the surface of the Moon in 2019 per propulsive landing, read our article: “First 2019 commercial mission to the Moon will be European” )
It could be used to dock, restock and refuel reusable moon landers or to mature techniques needed on crewed deep space mission, such as passive or active forms of shielding (e.g. electromagnetic shields), astronaut hibernation, artificial spin gravity and mission scale food production in space.
One of the more outlandish proposals would be to use the DSG as a counterweight for a Moon Space Elevator.
Although still unworkable around Earth, the technique is now in the realm of the possible and doable for a Moon version, with commercially available materials. Even a DSG in the vicinity of, or as a place to temporarily store the components, and not directly attached to this ‘Melevator’ (?), (e.g. due to safety/risk policies) would offer many operational benefits; in turn the DSG would live up to its ambition of becoming a real gateway and trade ecosystem.
Since the DSG will be built anyway, only the cable system would require additional funding. Several conceptual and operational synergies dictate that the time has arrived for investors to give it serious thought.
Once in place, separate strands can be attached to the same counterweight connecting multiple locations on the moon directly from orbit (e.g. the water ice at the south pole).
In essence all places of interest could become part of an instant cable rail network opening up the entire surface of the moon to exploration and commercial ventures. Mining and shipping Moon minerals/propellant/water to Low Earth Orbit will always be cheaper from the Moon, than it is from Earth, due to its lower gravity, and certainly if the technology required is as relatively simple as a cable train.
In an article dating back to 2005, Jerome Pearson completed a study for NASA Institute of Advanced Concepts which showed the concept is technically feasible within the prevailing state of the art using existing commercially available materials. (Pearson, Jerome; Eugene Levin; John Oldson & Harry Wykes (2005). “Lunar Space Elevators for Cislunar Space Development Phase I Final Technical Report” (PDF).)
And why not? It has become clear that the mass of the required cable is quite low. The DSG could act as a counterweight, and the cable itself would top out at a total weight of below 20 metric tons – and more likely less than 10 metric tons if M5 is used-; well within the masses that the NASA SLS, SPACEX BFR, F9 Heavy and Blue Origin New Glenn rockets will be able to deliver to the outpost in a single lift; a choice of launchers even Pearson couldn’t predict have predicted to become available so soon.
M5 is a synthetic fiber that is lighter than Kevlar or Spectra. According to Pearson, Levin, Oldson, and Wykes in their article The Lunar Space Elevator, an M5 ribbon 30 mm wide and 0.023 mm thick, [even at 100.000 km long (nvdr)], spanning from beyond L1, would be able to support 2000 kg on the lunar surface (2005). It would also be able to hold 100 cargo vehicles, each with a mass of 580 kg, evenly spaced along the length of the elevator. Other materials that could be used are T1000G carbon fiber, Spectra 200, Dyneema (used on the YES2 spacecraft), or Zylon. All of these materials have breaking lengths of several hundred kilometers under 1g.
With a single Falcon Heavy flight, capable of throwing >16 metric ton to the Moon, now costing below 100 million USD, and the synthetic fiber being quite easy and cheap to manufacture, the total cost of putting this elevator into production with support from the DSG could range well below USD 1 billion, much less than projections once made in earlier decades and as far as rail infrastructure projects on Earth go, a genuine bargain.
Operations would immediately scale to transportation costs of mere single digit thousands of dollars per delivered metric ton. Not the USD 50.000 per kilo, NASA projected around a decade ago for Moon-in-the-loop operations. Disruptive.
The benefits of ferrying medium payloads at low cost with a predictable railroad schedule would be transformational in opening up the exploration of the solar system. For cargo missions the rail cars, propelled with power from solar panels, would undercut and out-compete the costlier and less reliable chemically propelled moon landers, even in their reusable incarnations. The placement of an elevator system around Mars would be of similar technical difficulty and would solve some of the challenges related to landing in the thin atmosphere of Mars.
Furthermore, with the lengthy myriad of commercial companies making proposals to control rovers and In Situ Resource Utilization (ISRU) equipment on the Moon, the demand for a low cost way to ferry to and from the moon exists.
So is there any likelihood that commercial firms might actually be willing to build this?
The early bird catches the worm
Already in October 2011, the company LiftPort announced that they were actively pursuing a Lunar space elevator (video below). At the 2011 Annual Meeting of the Lunar Exploration Analysis Group (LEAG), LiftPort presented a paper on the prototype Lunar Elevator co-authored by Laine. And in August 2012, Liftport announced that the project may actually start near 2020. ( LADDER: The Development of a Prototype Lunar Space ElevatorT.M. Eubanks and M. Laine, Liftport Luna).
In space flight, all deadlines are stretchable, but it has become clear that a unique set of circumstances, including international political will, have converged upon an early return to the moon, to the point that the only thing really required for a Moon elevator engineering project to succeed is a decade of secure financial support from a sizable investor and an announcement to the international community that this mode of transportation will become available. Was it not said: “Build it and they will come?” (1989 Baseball Movie, Field of Dreams, Kevin Costner/Burt Lancaster)
It will be interesting to see if and when other Moon Elevator start up companies will follow suit and jump on the unique opportunity the placement of the DSG in L1 will offer.
|Stress Limit σ
(h = σ/ρg, km)
|Single-wall carbon nanotubes (laboratory measurements)||2266||50||2200|
|Toray Carbon fiber (T1000G)||1810||6.4||361|
|Aramid, Ltd. polybenzoxazole fiber (Zylon PBO)||1560||5.8||379|
|Honeywell extended chain polyethylene fiber (Spectra 2000)||970||3.0||316|
|Magellan honeycomb polymer M5 (with planned values)||1700||5.7(9.5)||342(570)|
|DuPont Aramid fiber (Kevlar 49)||1440||3.6||255|
|Glass fibre (Ref Specific strength)||2600||3.4||133|
(Update: To read a 2018 about the first commercial mission in 2019, read our article: “First 2019 commercial mission to the Moon will be European” )
*Update: since going to press the Deep Space Gateway has been renamed by the Trump administration into LOP-G (Lunar Orbital Platform-Gateway). Because it now uses a NRHO (near rectilinear halo orbit) orbit, a type of orbit that takes it into a slow periodic butterfly ellipse around the moon, and does not remain in a fixed position, it is no longer suitable as an anchor for a Lunar elevator. Nevertheless, a small commercial station in Moon Earth Lagrange 1 could serve the same purpose as described above.
ONESTAGETOSPACE is a genuine space effort seeking funds to further develop and build its MARVELOUS reusable vehicle. An innovative design allows us to decimate the operational cost of both orbital and interplanetary crewed missions, from surface to surface, over even the best industry competitors. This maturing site allows us to talk about our vehicle and to share stories about projects and people that or who inspire us on our long journey. If there is a story you feel we should cover, or a person that would like to be interviewed, let us know. Subscribe, like, share or support us with time, money or advice to help bring this project to fruition. It is ONESTAGETOSPACE, and you can become part of the adventure.