EML Gateway proposals have been around for a long time, including this 1991 piece by Wendell Mendell and Steven Hoffman, Strategic Considerations for Cislunar Space Infrastructure.
I believe, however, that the proposal to be outlined in this diary takes a slightly different tack:
(1) I link any EML Gateway to an RLL and (2) I propose that the EML Gateway be owned and operated by a neutral "entrepot" existing in between the major spacefaring powers.
Previous diaries include:
American Exceptionalism and Lunar Exploration
and
American Exceptionalism and Lunar Exploration #2
Acronyms shall be explained in the Tip Jar.
I have submitted an abstract to ISDC 2009 having the title: LaGrange Point Fuel Depots and the Entrepot Precedent and that abstract is presented in my prior diary American Exceptionalism and Lunar Exploration.
Any and every Kossack with an interest in space exploration and who can come to Orlando Florida at the end of May should attend the 2009 International Space Development Conference (ISDC) as it is "the annual conference for the National Space Society and has grown into the largest public space conference of the year. It is a national gathering for space-interested leaders and citizens to connect, re-energize and make plans for the future."
If my abstract is selected to present, I will need to prepare a 20 minute presentation and I currently envision using Powerpoint. This diary is intended as a working draft to present my arguments in an expanded format and receive feedback and from that I will distill down the material.
So here goes:
LaGrange Point Fuel Depots and the Entrepot Precedent
EML Gateway depot proposals have been around for a long time however the present proposal seeks to link such depots to the deployment of reusable lunar landers (RLL) and to seek deployment of such depots under the jurisdiction or national flag of a neutral, non-spacefaring power which can operate as a neutral, balancing the interests of the current human spacefaring powers (United States, Russia and China) and the emerging potential human spacefaring powers (European Union, India, Japan and perhaps Korea). The shared use of an EML depot and RLLs by the various spacefaring nations would enhance the Moon as a destination, promote global cooperation in space exploration and facilitate increased demand for transit from LEO which would stimulate programs seeking lower cost LEO access from Earth.
Prior visions for an EML Gateway facility
In Stanley Kubrick's epic movie, 2001: A Space Odyssey, Dr. Heywood R. Floyd travels from a LEO space station to the Moon on board a fully reusable nuclear powered lunar lander, the Aries 1b:
This trip followed Dr. Floyd arriving at the Earth orbit station via the fabled Pan American World Airways Orion III spaceplane.
Even if the Aries 1b vision (shuttling between LEO to lunar surface in the same vehicle) someday comes to pass, at the moment that would be very much more difficult to accomplish than shuttling between the lunar surface and a point in lunar orbit, such as EML-1 and/or EML-2.
(Of note: In 2010: Odyssey Two the large monolith is said to be located at the Io-Jupiter L1 point -- JI1 -- which would be a stable location if the monolith had station keeping abilities, which would seem likely.)
Anyway, the importance of 2001: A Space Odyssey for my presentation lies in the recognition by Clarke and Kubrick that a reusable lunar lander is the logical means to access the lunar surface.
Strategic Considerations for Cislunar Space Infrastructure
In 1991, Wendell Mendell and Steven Johnson presented a cogent paper arguing for the strategic significant of an EML Gateway facility. The paper's Abstract:
The international low Earth orbit (LEO) space station ultimately derives from the vision of Wernher von Braun (as part of a Mars exploration strategy) via the 1969 NASA Space Task Group. In its contemporary NASA incarnation, the space station has been touted as a research laboratory with a broad agenda. Unfortunately, the LEO environment is inhospitable for the many of the advertised research objectives. More importantly, space debris in LEO and in GEO is a long-term threat. We argue that a crewed space station at the libration point between the Earth and the Moon provides an environment that is more suitable for almost every research objective, from microgravity to planetary exploration. An important corollary of the existence of an L1 space station is the development of a reliable, low-cost heavy lift vehicle by an international consortium for an international market. Therefore, an international decision to support what we call Space Station ½ will have broad implications for space development beyond the objectives of the program itself. This example illustrates how strategic goals associated with human exploration will be best served by careful reconsideration of appropriate infrastructure for human presence in cislunar space.
A short selection of excerpts from this paper:
Let's assume that we have been given the mandate to plan for permanent human presence in space for the long term. The scope includes human exploration of the planets as well as permanent human presence in Earth orbit. The crew will conduct life science research on human response to the space environment and will operate a space transportation node for planetary exploration. The node will also support astronomy and astrophysics research, microgravity research, and Earth observations. Where should this node be located?
It should be near the edge of the Earth's gravity well so that reusable interplanetary vehicles can come and go with a minimum of propellant. It should be accessible from the Earth and the Moon with a minimum of constraints on launch windows. There should be no hazard from artificial space debris. The region of space in which it sits should support colocated unmanned scientific platforms which can be reached from the space station by small delta-v transfers. The fuel requirements for station-keeping should be small. A good view of the Earth and the Moon would be useful for scientific observations and would provide the crew with a sense of place. International character would be enhanced by a location independent of political boundaries on the Earth.
These criteria are satisfied by volumes of space surrounding the unstable Earth-Moon libration (or Lagrangian) points. The Lagrangian point L1 between the Earth and the Moon is best for planetary observations and the sense of place. The far side of the Moon has been set aside by international agreement as a radio-quiet zone for scientific research since it is the only environment in the solar system completely shielded from terrestrial electronic emissions. Therefore, the Lagrangian point L2, on the far side of the Moon from the Earth, is unsuitable for a space station even though the location is probably better for astronomy.
* * *
Since Space Station ½ sits in a politically neutral location in space, it can be supported from many countries. The launch vehicle development can take place under an international consortium of aerospace companies for an international market. With Energiya-class launch capabilities routinely available in several countries, the possibilities for space exploration and development multiply. In other words, the existence of Space Station ½ will be a catalyst for many new ventures unrelated to the space station program itself.
PDF -- The Lunar L1 Gateway: Portal to the Stars and Beyond, AIAA Space 2001
In this paper, Cal Tech's Martin Lo and Shane Ross expand and amplify the argument for an EML1 Gateway by articulating the orbital mechanics which favor this location and by pointing out that EML-1 and its sibling EML-2 constitute on-ramps to the so-called Interplanetary Superhighway described by Wikipedia as follows:
The Interplanetary Transport Network (ITN) is a collection of gravitationally determined pathways through the solar system that require very little energy for an object to follow. The ITN makes particular use of Lagrange points as locations where trajectories through space can be redirected using little or no energy. These points have the peculiar property of allowing objects to orbit around them, despite the absence of any material object therein.
If space has strategic cross-roads, the LaGrange Points are the most strategic of all.
Where the "L" is EML-1 . . .
As background and introductory illustration, here is a 17 second You Tube depicting the SOHO telescope located at SEL-1 (the Sun - Earth LaGange point 1)
SEL-1 = Sun-Earth-Lagrange 1
If we were to replace the Sun with the Earth and the Earth with the Moon, a facility located at the 1st Lagrange point would be at EML-1.
EML-1 = Earth-Moon-Lagrange 1
This link explains the Earth-Moon Lagrange points and has a nice diagram showing the 5 EML points. Key quotes:
An object at L4 or L5 is truly stable, like a ball in a bowl: when gently pushed away, it orbits the Lagrange point without drifting farther and farther, and without the need of frequent rocket firings. The Sun's pull makes any object in the Earth-Moon L4 and L5 locations "orbit" the Lagrange point in an 89-day cycle. These regions could be ideal for the Space habitats devised by Gerard K. O'Neill in 1969.
An object at L1, L2, or L3 is meta-stable, like a ball sitting on top of a hill. A little push or bump and it starts moving away. A spacecraft at one of these points has to use frequent, small rocket firings or other means to remain in the area. Orbits around these points are called 'halo orbits'. The Solar and Heliospheric Observatory (SOHO) is in a halo orbit around the Sun-Earth L1 position, about a million miles Sunward from Earth, and the Microwave Anisotropy Probe (MAP), is in a halo orbit around the Sun-Earth L2 Position, about a million miles in the opposite direction. These are the first spacecraft to be positioned in Lagrange orbits.
Well, yes and no. The math is correct -- objects are EML4 and/or EML 5 are stable however "meta-stable" is better for transportation nodes as they offer greater dynamic opportunity.
The Entrepot Precedent
Entrepot is a French word that literally means "warehouse" however Wikipedia explains how this word can be added to historical cities:
An entrepôt (from the French "warehouse") is a trading post where merchandise can be imported and exported without paying import duties, often at a profit. This profit is possible because of trade conditions, for example, the reluctance of ships to travel the entire length of a long trading route, and selling to the entrepôt instead. The entrepôt then sells at a higher price to ships traveling the other segment of the route. Today, this use has mostly been supplanted by customs areas.
Entrepôts were especially relevant in the Middle Ages and in the early modern period, when mercantile shipping flourished between Europe and its colonial empires in the Americas and Asia. For example, demand for spices in Europe, coupled with the long trade routes necessary for their delivery, led to a much higher market price than the original buying price. However, traders often did not want to travel the whole route, and thus used the entrepôts on the way to sell on their goods. However, this also led to even more attractive profits for those who persevered to travel the entire route. An example of such an early-modern entrepôt is the 17th-century Amsterdam Entrepôt.
Classic entrepot cities include Hong Kong, Singapore, Dubai and Cape Town. Of those, only Singapore (and perhaps Dubai) truly retains its full independence as a "free city" available to facilitate trade. Hong Kong is now under China's jurisdiction just as Cape Town is an integral part of South Africa. But in history, such locations facilitate trade across difficult routes and between entities that might not otherwise be on the best of terms with one another.
The shared use of an EML depot and RLLs by the various spacefaring nations would enhance the Moon as a destination, promote global cooperation in space exploration and facilitate increased demand for transit from LEO which would stimulate programs seeking lower cost LEO access from Earth. A shared use EML depot plus RLL would offer synergy with an American flag LEO depot at 28 degrees, a Russian flag depot at 51 degrees, a Chinese flag depot at 20 degrees (Hainan Island launch facility), an Indian flag facility at 14 degrees (Sriharikota launch facility) and equatorial depots deployed to support Kouru.
The realities of international geo-politics and the apparent inability of any one spacefaring nation to fund (by itself) all aspects of a robust lunar exploration program suggests that mutual benefits could be attained if an EML depot plus RLLs were owned and operated by an entity not under the jurisdiction of any current spacefaring nation. As an example, such facilities could be owned and operated by entities having situs within sovereigns such as Singapore or Dubai, historic entrepot cities. The Isle of Man offers another possible jurisdiction.
Throughout world history, entrepot cities facilitated trade along difficult routes and between parties not on amicable terms. With respect to future cis-lunar commerce, a Singapore or Isle of Man flagged EML depot could accommodate, service and fuel vessels from every spacefaring nation while remaining neutral during the ebb and flow of geo-political antagonisms. Further, once genuine commercial and industrial development of the Moon commences and once humanity initiates travel beyond cis-lunar space, the commercial value of an EML depot can only be expected to increase (perhaps substantially) since real estate is always valued by three factors: location, location, location.
Moon or Mars or NEOs?
The Planetary Society asserts that it is the most influential of space advocacy organizations and in November of 2008 they issued a "road map" critical of NASA's current direction. That paper is titled:
Beyond the Moon: A New Roadmap for Human Space Exploration and the "highlights" include these proposals:
* focusing on Mars as the driving goal of human spaceflight
* deferring humans landing on the Moon until the costs of the interplanetary transportation system and shuttle replacement are largely paid
* achieving a step-by-step approach of new achievements in interplanetary flight, including a human mission to a near-Earth object
Our own Vladislaw's most recent diary mentions an upcoming review of ESAS and Ares and Vladislaw talks about Ares versus EELVs versus Jupiters which is a topic very much on the table.
However, there are suggestions that NASA's next destination could also be on the table possibly postponing a lunar return in favor of a human visit to an NEO asteroid. If this occurs, expect lunar advocates such as Dr. Paul Spudis and Dennis Wingo to be most unhappy and quote possibly the somewhat dormant "Moon versus Mars" wars might re-emerge.
Over the last few years there was much concern that Dr. Griffin intended a lunar "touch-n-go" -- NASA would land on the Moon to regain deep space experience however building up lunar infrastructure was seen as a dead end (a cul de sac) and therefore a lunar exit strategy needed to be part of any lunar return strategy.
Seen in this light, Ares 1 and Ares V make terrific sense. By being too expensive to fly frequently, Congress would be discouraged from seeking to build up any significant lunar infrastructure and would instead (in theory) be more amenable to a sprint to Mars once American boots again stirred up lunar dust.
But if folks other than Americans became active on the Moon then interests of American prestige would point towards doing Mars missions or other missions beyond cis-lunar space.
This is why I believe that an entrepot flagged EML-1 Gateway would allow advocates of lunar development to initiate lunar exploration through an alliance of American NewSpace interests and foreign governments while helping NASA remain focused beyond cis-lunar space, on Mars and the asteroids.