|The Earth seen rising above the Lunar horizon aboard Apollo 17, the last human mission to the Moon (Credit: NASA)|
by Marcel F. Williams
|SLS crew & cargo vehicles|
But the Space Launch System could also be utilized to do a lot more.
The SLS could be used to deploy a reusable cis-lunar architecture that could give passengers aboard Commercial Crew vehicles easy access to the surface of the Moon and to other commercially viable regions within cis-lunar space.
Below is a possible scenario that could make this happen by using a standard reusable ETLV (Extraterrestrial Landing Vehicle) derived architecture, starting in the year 2021.
EML (Earth Moon Lagrangian point);
LEO (Low Earth Orbit);
SLS (Space Launch System);
MPCV (Multipurpose Crew Vehicle);
CM (Command Module)
ETLV-2 (crewed Extraterrestrial Land Vehicle;
ETLV-2R (Unmanned Automated ETLV-2);
C-ETLV-4 (cargo lunar lander);
WFD-OTV-5 (Water- Fuel Depot Orbital Transfer Vehicle);
WFD-LV-5 (Water- Fuel Depot Lunar Landing Vehicle);
RWT-LV-5 (Reusable Water Tanker Lunar Landing Vehicle);
LRH (Lunar Regolith Habitat);
Water Bug (Robotic Microwave Water Extraction Vehicle);
ATHLETE (All-Terrain Hex-Legged Extra-Terrestrial Explorer)
|Earth-Moon Lagrangian Points (Credit: NASA)|
LEO to LLO (~2 days) - 4.5 km/s dv
LEO to LLO (~4 days) - 3.97 km/s dv
LEO to EML1 (~2 days) - 4.41 km/s dv
LEO to EML1 (~4 days) - 3.77 km/s dv
EML1 to or from LLO (~2 days) - 0.75 km/s dv
EML1 to or from LLO (~3 days) - 0.64 km/s dv
LLO to or from the Lunar surface - 1.87 to 2.1 km/s dv
LEO: Low Earth Orbit; TLI: Trans-Lunar Injection; LLO: Low Lunar Orbit;
EML1: Earth Moon Lagrange Point 1
(Credit John Connolly: NASA-JSC - 2012)
|Unmanned ETLV-2R docked with the WFD-OTV-5 fuel depot at ELM1|
Derived from the Extraterrestrial Landing Vehicle (ETLV), the WFD (Water Fuel Depot) OTV (Orbital Transfer Vehicle) will utilize the same cryotanks used for the ETLV-2. But these will be five in number instead of two, fixed within a higher cruciform in order to enhance the depot's ability to store the maximum amount of cryofuel. The WFD-OTV-5 would be capable of storing nearly 70 tonnes of LOX/LH2 fuel in addition to more than 100 tonnes of water. However, when the WFD-OTV-5 fuel depot is initially deployed at EML1 by the SLS upper stage, it will contain only 20 tonnes of fuel and no water because the SLS upper stage will only be able to deliver a little more than 30 tonnes to the Lagrange point.
The first ETLV-2 mission to the lunar surface under this scenario will be an unmanned mission to the South Lunar Pole. But first the SLS will launch The ETLV-2R will be launched by the SLS to the fuel depot at EML1. Although the ETLV-2R would be nearly fully fueled, some additional fuel would be required in order for the vehicle's return to the Lagrange point after landing on the lunar surface.
Once on the lunar surface, a variety of small mobile robots will be deployed to explore the polar region, test water extraction technologies, and return a variety of samples from lunar regolith. After a few days, or a few weeks, the ETLV-2R will return to L1.
A similar mission will occur with the third launch of the SLS in 2021. But the unmanned destination will be the North Lunar Pole. Again, after a few days, or a few weeks, the ETLV-2R will return to L1.
So the end of both unmanned missions to the lunar surface will not only retrieve lunar samples from the lunar poles but will twice demonstrate the ability of the ETLV-2 vehicle to travel to and from the lunar surface from L1 on a single fueling of it's twin tanks. These two demonstrations of the ETLV-2, to and from the lunar surface, should enhance the safety of the first crewed mission of the ETLV-2 in 2022.
|MPCV (Multipurpose Crew Vehicle) Credit: NASA|
Astronauts will return to Earth aboard the CM of the MPCV, demonstrating the vehicle's ability to travel within cis-lunar space while also bringing back precious regolith samples from the north and south lunar poles.
|C-ETLV-4 and the ETLV-2 cargo and crew lunar landing vehicles|
The first SLS launch of 2022 will send the C-ETLV-4 lunar cargo vehicle directly to the lunar surface. An ATLETE robot will deploy two small mobile excavators, two mobile sintering robots, and a single back hoe for depositing regolith into the walled interior of human habitat structures.
|ATLETE robot for offloading cargo from the C-ETLV-4 (Credit: NASA)|
|Lunar excavation robots (Credit: Astrobotic Technology and Carnegie Mellon)|
The mobile excavators will be used to remove rocks and level the surface area for eventual sintering. Mobile sintering machines will move over the paved area using microwaves to melt the lunar regolith, creating a hard sintered layer approximately 0.5 meters deep and a smooth solid surface approximately 3 to 5 cm deep. Two widely separated areas will be prepared by the excavators and the sintering machines. One area will be for the deployment of the Lunar Regolith Habitats. The other area will be exclusively prepared for landings by the ETLV-2, C-ETLV-2, Reusable Water Tankers, and lunar fuel depots. Both areas will be connected to each other by a paved and sintered road perhaps a kilometer or more long.
|An electric powered (battery or fuel cell) back hoes would have to be deployed to the lunar surface in order to deposit lunar regolith inside of the regolith walls of a Lunar Regolith Habitat (LRH) (Credit: Volvo)|
Once it is in position, the LRH-1 will automatically expand its solar panel to recharge the habitat batteries. An SLS hydrogen tank derived pressurized habitat will automatically expand its wall panels to produce a rigid and continuous wall around the pressurized area, creating a 2 meter wide cavity between the wall and the pressurized habitat. The lunar back hoe will deposit lunar regolith inside of the cavity to the top of the regolith wall which will also extend approximately two meters above the top level of the pressurized habitat. This will provide astronauts, scientist, and other visitors to the habitat with thermal and micrometeorite protection while also protecting them from the radiation of major solar events and while also reducing their annual exposure to cosmic radiation to levels below that required for radiation workers on Earth. This will allow astronauts and scientist to continuously remain at such habitats for more than a decade without coming close to their lifetime NASA limits for radiation exposure.
Within the 8.4 meter in diameter pressurized housing, there would be two levels each with approximately 55 square meters of area. So each habitat level would be about the size of a one bedroom apartment on Earth. In total, these two levels would have more floor area than the average family home in Great Britain. Airlocks derived from the ETLV tanks would be located below the pressurized habitat area.
The last two SLS launches in 2022 will send the ETLV-2 and the MPCV to EML1. Again, the water will also be delivered to the fuel depot at L1 during the MPCV launch to EML1. After adding additional fuel, the ETLV-2 will deliver six astronauts, four Americans and two foreign guest to the lunar surface. But they will only spend a few days or a few days on the lunar surface to inspect the lunar habitat and to collect more lunar samples. The ETLV-2 will return the astronauts back to EML1 where it will dock with the MPCV for the crews return to Earth. The ETLV-2 will remain at L1 for future use once new fuel is being manufactured at L1 from lunar water resources. And it will be part of a fleet of three reusable vehicles starting in 2025.
The first SLS launch of 2023 will send a solar powered water storage and cryofuel producing depot to the new lunar outpost. This will be followed just a few weeks later by the C-ETLV-4 deployment of two mobile cryotankers derived from ETLV cryotank technology. The mobile cryotankers will be used to extract cryofuels from the WFD-LV-5 lunar fuel depots in order to refuel lunar landing vehicles. The mobile cryotankers will also be capable of scavenging residual fuel from the dormant C-ETLV-4 vehicles.
2023 will end with another pair of SLS launches for the ETLV-2 and MPCV in order for another temporary human visit to the lunar outpost .
A second SLS launch in 2024 will use the C-ETLV-4 to deploy a second habitat to the lunar outpost (LRH-2). The second habitat will double the area for human accommodations at the outpost. Each habitat will also serve as backup accommodations for the other in case there is a serious malfunction at one of the habs.
Two SLS launches will end the year, bringing the first long term inhabitants to the lunar outpost. Some of these individuals will remain on the lunar surface for more than a year simply to determine if there are any deleterious physical or psychological effects for human individuals after living in a low gravity environment for more than a year. Before the first human attempts to venture to the orbit of Mars and to the Martian surface, some astronauts will have to eventually stay on the lunar surface as long as four years. The results of these simple human test on the lunar surface could have enormous implications for humanity's future in the rest of the solar system.
A single SLS launch in 2025 will deploy two reusable lunar water tankers to the lunar outpost. Each vehicle will be capable of transporting more than 50 tonnes of lunar water to the EML1 fuel depots per flight while still being able to return to the lunar surface. With their CECE engines, each vehicle should be capable of at least ten round trips between ELM1 and the lunar surface before their engines or the entire vehicle is replaced.
|RWT-LV-5 transferring lunar water to the WFD-OTV-5 at ELM1|
|An OTV-2 preparing to dock with an Aerobrake Shield and another OTV-2 docked with an Aerobrake Shield|
The deployment of the reusable OTV-2 vehicles will mean that an SLS launch of the MPCV will no longer be necessary in order to transport astronauts to the Earth-Moon Lagrange points. However, NASA astronauts will still need to be able to get to LEO in order to access the OTV-2. But by 2025, NASA should have a wide variety of Commercial Crew and foreign vehicles available to give NASA astronauts access to orbit.
|Dream Chaser (Credit: Sierra Nevada Co.)|
|Dragon (Credit: Space X)|
|CST-100 (Credit: Boeing)|
|SKYLON (Credit: REACTION ENGINES LTD)|
|OTV-2 docked with an ETLV-2 lunar landing vehicle at EML1|
A single SLS launch will deploy two additional fuel depots (WFD-OTV-5) to LEO. One will use its own engines to reach EML1 while the other will remain at LEO to refuel the OTV-2 vehicles. Once a LEO fuel depot begins to run low on fuel, it will transport itself to EML1 to be refueled with water from the lunar tankers in order to manufacture enough fuel for its redeployment back at LEO.
|X-Ray of Skylab II with its SLS derived pressurized habitat at ELM1 (Credit: Griffin)|
The final SLS launch in 2025 will be to deploy an SLS hydrogen fuel tank derived habitat with an internal hypergravity centrifuge to EML1. Lunar water exported to L1 will provide enough radiation shielding for the Lagrange point habitat to protect astronauts from a major solar event. The deployment of the lunar water shielded Skylab II will be first test of a potential interplanetary habitat for possible manned missions to the orbit of Mars.
Marcel F. Williams
© 2014 MuOmega Enterprises
© 2014 MuOmega Enterprises
Links and References
- LOW-COST LUNAR COMMUNICATION AND NAVIGATION
- Utilizing Space Shuttle Main Engines (SSME) for Early SLS Cargo Launches and Commercial Crew Destinations
- An SLS Launched Cargo and Crew Lunar Transportation System Utilizing an ETLV Architecture
- The SLS and the Case for a Reusable Lunar Lander
- Mission and Implementation of an Affordable Lunar Return (Spudis & Lavoie)
- Using the resources of the Moon to create a permanent, cislunar space faring system (Spudis & Lavoie)
- The Future of NASA and the Commercial Crew Program
- How ATHLETE Robots could Deploy Pressurized Habitats and other Large Payloads to the Lunar Surface
- Microwave Sintering of Lunar Soil: Properties, Theory, and Practice
- Cooking Up Water From the Moon? NASA Studies Water Extraction With Microwaves