Friday, January 11, 2019

Elephant Artist


More than 2000 years ago, the Greek philosopher, Aristotle, referred to the elephant as "the beast which passeth all others in wit and mind."






Monday, December 24, 2018

Utilizing the Centaur V and ACES 68 for Deep Space SLS Missions

by Marcel F. Williams
Artist rendition of  ULA's future upper stage precursor to the IVF modified ACES 68, accommodating 68 tonnes of LOX/LH2 propellant (Credit: United Launch Alliance)

NASA currently envisions three launches for the SLS (Space Launch System) using a Block I configuration and  consisting of an ICPS (Interim Cryogenic Propulsion Stage) for its upper stage.  The basic Block I vehicle will be capable of deploying at least 70 tonnes to LEO. However, by utilizing the ICPS as an upper stage that can accommodate  27 tonnes of propellant, the Block I configuration with an ICPS upper stage will be able to deploy at least 95 tonnes of payload to low Earth orbit.

A Block IB configuration with an EUS (Exploration Upper Stage) is expected to be introduced by 2024. The  EUS will be able to  accommodate 128 tonnes of LOX/LH2 propellant. And this will enable the Space Launch System to deploy up to 105 tonnes of payload  to LEO.  NASA currently plans to use the Block IB configuration to assemble the future Lunar Gateway at NRHO (Near Rectilinear Halo Orbit). The Lunar Gateway will serve as a bridge for Lunar and Martian operations, substantially reducing the delta v requirement to reach the orbits of the Moon and Mars.


NASA's Current  Launch Sequence for the SLS

2020:

The SLS Block I launch vehicle will deploy an unmanned Orion spacecraft to a Distant Retrograde Orbit (DRO) before returning the capsule to the Earth. DRO is interesting because of its lack of station keeping requirement. Such a distant equatorial orbit of the Moon might make  DRO  a prime location for massive rotating artificial gravity habitats perhaps sometime  in the second half of the 21st century. It might also be a good location for small asteroids imported into cis-lunar space for potential exploitation.

2022:

The second SLS  Bloch I launch is scheduled  to send a crewed Orion spacecraft around the Moon as an inaugural human occupied beyond LEO spaceflight for the SLS system.

2023: 

The third scheduled SLS Block I launch  will be used to deploy  the Europa Clipper to Jupiter orbit in order to study the surface of its icy moon, Europa.

2024:

The first launch of the SLS Block IB is scheduled for 2024. It will consist of an Orion crew of four plus a ten tonne component of the Lunar Gateway which will be assembled at NRHO . This location will eventually give crewed  vehicles weekly access to the lunar surface with as little as 12 hours of travel time to and from the surface of the Moon.

2026:

Four subsequent SLS Block IB flights will be required to completely assemble the Lunar Gateway by 2026.

SLS Block I Cargo with ICPS upper stage capable of deploying 95 tonnes to LEO (Credit: NASA)
SLS Block I without upper stage, capable of deploying 70 tonnes to LEO (Credit: NASA)


The Flaws in NASA's SLS Plans


One. Only one or two  SLS launches are required to deploy the Lunar Gateway to NRHO-- not five SLS launches. Of course, the amount of mass that can be deployed to NRHO by the SLS is substantially reduced under the NASA scenario because of the joint launch of the Orion spacecraft and Service Module. This would be  an unnecessary joy ride for NASA astronauts that would greatly inflate the cost of deploying the Gateway while also significantly delaying its full implementation.

Why spend more than two to five times as much as you have to deploy the Lunar Gateway when dollars for NASA's human spaceflight related programs are so hard to come by? Plus NASA needs more funding to help private companies develop lunar crew landing vehicles, space propellant depots, extraterrestrial habitats, and interplanetary crew transport spacecraft.

Two.  Under NASA's current scenario, the Lunar Gateway wouldn't even start to be assembled until 2024 with a completion date around 2026. Again, a totally unnecessary delay in deployment.

An SLS Block I with an ICPS upper stage could probably deploy a complete SLS derived Deep Space Habitat to NRHO as early as 2022 that weighs about 20 tonnes-- without consumables. Food and water could subsequently be launched to the Gateway by commercial launch vehicles.

An SLS Block IB, would be able to deploy SLS derived Deep Space Habitat concepts weighing  22 tonnes for 353 cubic meters of habitable pressurized volume and 28 tonnes for 519 cubic meters of habitable pressurized volume with a single launch in 2024. That would still be two years earlier than NASA's current Lunar Gateway completion plans.

However, a large private commercial upper stage is currently being developed by the ULA (United Launch Alliance) that will be used to deploy payloads for the Air Force (Space Force?). And the ULA's Centaur V could be certified for military payloads in 2021 and ready for utilization in 2022.

If  the SLS was used to deploy a large commercial upper stage (Centaur V) to LEO, NASA could deploy a 28 tonne SLS derived Deep Space Habitat to NRHO with just two launches.  Assuming a maximum dry weight of no more than seven tonnes for the Centaur V, an SLS Block one launch could deploy the Centaur V to orbit with at least 63 tonnes of propellant. An SLS Block I with an ICPS upper stage could deploy the Centaur V with 68 tonnes of propellant to LEO plus 20 tonnes of additional payload for, perhaps,  another ICPS with at least 16 tonnes of additional propellant. 

After docking with an SLS payload deployed to LEO by a previous SLS launch, the Centaur V should be easily capable of transporting more than 30 tonnes of payload to NRHO.

However, the preceding SLS Block I launch would be able to deploy up to 70 tonnes of payload to LEO. So you could actually  deploy two 28 tonne habitats to LEO (just 56 tonnes) with one destined for NRHO after the next SLS upper stage launch-- while the other 28 tonne habitat remains at LEO as a potential replacement for the ISS.

Replacing the ISS with a new space station would possibly save NASA up to $4 billion a year!

An SLS derived LEO habitat wouldn't be a space laboratory, it would simply be a habitat used for NASA and Space Force astronaut training and for the training of astronauts from foreign space agencies. It could also be a used as a destination for wealthy space tourist and space entrepreneurs.  Small commercial launched space laboratories could be co-orbited near the LEO habitat while lab specialist use the SLS derived habitat as a hotel, visiting their floating laboratory only when necessary to add or retrieve materials.

Alternatively, NASA could deploy three 22 tonne SLS derived habitats to LEO with one destined for NRHO with the other two remaining at LEO. One could be used exclusively for NASA and the Space Force with the other being auctioned off to a private space company for space tourism or to accommodate the needs of foreign space agencies.

While the above scenario might delay the first crewed flight of the SLS until 2023 (just one year), it would actually give astronauts a place to go on their first SLS flight in 2023. Of course, NASA could still have a  test flight of a crewed Orion in 2021 instead of 2022.  NASA astronauts could use commercial crew vehicles to travel to LEO to inspect the Gateway habitat before its deployed to NRHO.

Three.  There's no logical reason to waste an SLS launch for a flyby mission of Europa. The Europa Clipper can probably be deployed by commercial launch vehicles. However, an orbital mission to Europa is questionable since the moon Callisto would be much easier to access. Callisto is the only place in Jupiter space where human outpost could be set up for  potential colonization.  A human outpost on the surface of  Callisto would make it substantially  easier to  explore  Europa, Ganymede, and Io (all within Jupiter's deadly radiation belt) with robots remotely controlled from the surface of Callisto. A better near term use for a non human spaceflight related launch of the SLS would be the deployment of space telescopes with mirror diameters even larger than the James Webb.
16.5 meter long 8.4 meter in diameter SLS derived orbital habitat (Credit: NASA)
13.5 meter long 8.4 meter in diameter SLS derived orbital habitat (Credit: NASA)


Propellant Depots and the Future of the Orion

The utilization of reusable vehicles for the human exploration, pioneering, and exploitation of the lunar surface is one of the primary reasons for having a Lunar Gateway at NRHO.  Reusable spacecraft will, of course, require propellant depots.

Once the Lunar Gateway is deployed, co-orbiting propellant depots can also be deployed to NRHO by private commercial launch companies. NASA breakthroughs in zero boil off (ZBO)  liquid hydrogen storage should make it possible for commercial launch companies to deploy propellant tank derived  LH2 (liquid hydrogen) and liquid oxygen (LOX) storage tanks to NRHO that don't leak any hydrogen or oxygen. More sophisticated technologies could allow the solar power production and liquefaction of  hydrogen and oxygen from water in space which could substantially reduce launch complexity and cost for commercial launch companies.

The SLS propellant tank technology derived EUS might have questionable utility if NASA is already using the Centaur V and, subsequently, the ACES-68 to deploy heavy payloads to deep space locations.
Notional ACES 68 with BE3 Engine (Credit: ULA)

With its Integrated Vehicle Fuel (IVF) technology, the ULA's ACES-68 successor to the Centaur V could be in operation as early as 2023 but is currently planned to go into operation within the 2024 to 2025 time frame. It now seems likely that the ULA will allow Lockheed Martin, one of its parent companies, to be first to develop IVF technology for its future reusable crewed lunar landing vehicles. In tandem (on either side of an orbiting payload) two such ACES vehicles could transport payloads exceeding 70 tonnes from LEO to NRHO or to Low Lunar Orbit. A single ACES 68 could deploy an equal amount of payload to Mars orbit from NRHO; so massive amounts of water or propellant deployed to NRHO could easily be later deployed to Mars orbit from NRHO.

If propellant depots are deployed at LEO and NRHO, the ACES-68 could replace the ICPS and the Service Module for the Orion space capsule. This would make the Orion a completely reusable vehicle for transporting astronauts between LEO and NRHO. So no longer would the Orion spacecraft have to be deployed by the SLS for deep space missions.    The ULA's Vulcan spacecraft could deploy the reusable Orion/ACES to LEO, fueling the ACES 68 booster at a LEO propellant depot before heading for NRHO or Low Lunar Orbit.

So, in theory,  astronauts could board a commercial launch vehicle (Falcon 9/Dragon, Atlas V/Centaur/CST-100, etc.) that transports them to LEO. The could then dock with an already propellant depot fueled  Orion/ACES vehicle for transport to the Lunar Gateway or to Low Lunara Orbit. Again, no SLS launch would be required which means that the heavy lift vehicle could be more properly used to transport heavy payloads to LEO.

Notional Orion/ACES reusable shuttle with crew hab approaches  SLS derived Lunar Gateway at NRHO (Near Rectilinear Halo Orbit). (After NASA and ULA)


The Future of the EUS

If NASA eventually uses commercial upper stages such as the Centaur V and the ACES 68  to transport large and heavy payloads initially transported to LEO by the SLS then the space agency could delay the deployment of the EUS and focus on developing a far more enhanced orbital transfer vehicle. An SLS derived EUS  equipped with IVF and cryocooler technologies could make such a vehicle reusable. Such a vehicle could simply use the SLS core stage liquid oxygen tank as a liquid hydrogen tank while also deriving a smaller oxygen tank from the same technology.

Such a reusable vehicle  could accommodate more than 345 tonnes of LOX/LH2 propellant. And it could be used to transport large habitats and their crews  to the orbits of Mars, Venus, and to the NEO asteroids from NRHO. The performance of such a reusable interplanetary crew transport could also be greatly enhanced by coupling it with a  twin transport or just a reusable ACES booster with 68 tonnes of propellant. Propellant depots in Mars orbit would be required for the the return journey to Earth. But, again, the water or propellant could be routinely transported to Mars orbit from water or propellant transported from the lunar surface to NRHO. Eventually, however, propellant depots in Mars orbit could be routinely supplied with water or propellant extracted from the regolith of the martian moons, Deimos and Phobos. And it might even be economical to transport liquid hydrogen from the surface of Mars from reusable spacecraft to orbiting depots to be used with liquid oxygen extracted from the martian moons for propellant. 


An Alternate SLS Launch Scenario 



2020:

SLS 1: Unmanned SLS Block I launch of  Orion/SM/ICPS to DRO (Distant Retrograde Orbit)


2021:

SLS 2: Crewed SLS Block I launch of  Orion/SM/ICPS to TLI (Trans Lunar Injection) around the Moon

(Beginning of deployment of small mobile robots to the lunar surface by commercial launch companies) 


2022:

SLS 3: Unmanned SLS Block I launch of two 28 tonne  SLS derived microgravity habitats to LEO.

(Two Commercial Crew launches to LEO to inspect the twin microgravity habitats.)

SLS 4:  SLS Block I launches Centaur V to LEO. Centaur five docks with Lunar Gateway at LEO and transports the fully complete deep space habitat to NRHO (Near Rectilinear Halo Orbit)


2023:

SLS 5: Crewed SLS Block I launch of  Orion/SM/ICPS  to Lunar Gateway at NRHO.

SLS 6:  SLS Block I with ICPS upper stage launches a Centaur V with an 8 meter class space telescope to ESL2 (Earth-Sun Lagrange Point 2).  The new space telescope will have an 8 meter plus monolithic primary mirror housed within a 12 meter in diameter payload fairing. And it will join the with join the 6.5 meter in diameter James Webb telescope at  ESL2. The diameter for the mirror for the Hubble Telescope was 2.4 meters.  The development of such a enormous fairing size for the SLS will  greatly enhance the launch vehicles unique ability  to accommodate exceptionally large payloads. NASA needs to stop entertaining smaller payload shrouds for the SLS that could nullify its advantage over other launch systems.   

(Commercial launch companies begin the continuous deployment of tanks of LOX and LH2 to depot clusters at  LEO and NRHO)

{NASA begins using new RS-28 engines for the SLS core vehicle. Hopefully, some meager funding to develop an SLS-B (the SLS without  Solid Rocket Boosters) with a commercial Centaur V or ACES upper stage and a commercial CST-100, Dream Chaser, Dragon, or maybe even an Orion as the crew capsule. This would allow more frequent use of the SLS core stage and its RS-25 engines which should help to substantially reduce the overall cost of SLS launches.}   


2024:

SLS 7: SLS Block I launches two reusable Lockheed Martin Lunar Crew Landing Vehicle (LCLV) equipped with advanced IVF and cryocooler technology. One LCLV will be launched with enough fuel to self deploy itself to the Lunar Gateway at NRHO. The LCLV already fueled with LH2,  will utilize a LEO orbiting LOX depot in order to fuel itself for self deployment to NRHO.

Both Lunar Crew Landing Vehicles  will be fueled and tested (unmanned) at NRHO with each traveling to opposite lunar poles to deploy mobile robots to the surface via their lift elevators.  Some of the mobile robots will collect regolith samples for return to the Lunar Gateway and eventually to Earth. A few weeks later, one LCLV will be deployed to the surface of the far side of the Moon to collect regolith more lunar regolith samples while proving the vehicle's reusability.

{First NASA /ULA funded unmanned test of a reusable Orion/ACES to NRHO followed by the first crewed Orion/ACES to the Lunar Gateway at NRHO. The reusable vehicle will be launched into orbit by the ULA Vulcan rocket. The success of  reusable Orion/ACES spacecraft and reusable Lockheed Martin Lunar Landing Vehicle (used for crew transport between LEO and NRHO) should end the necessity of using the SLS to deploy astronauts to NRHO Gateway}

SLS 8: Last crewed SLS Block I launch of  Orion/SM/ICPS to Lunar Gateway at NRHO.  

After the six member crew arrives at NRHO, four astronauts will climb aboard one of the Lunar Crew Landing Vehicles to travel to one of the lunar poles (The first Americans to land on the lunar surface since 1972). If the crew on the lunar surface should have some serious difficulties attempting to return to the Lunar Gateway, the remain astronauts at NRHO will use the second LCLV to rescue the astronauts from the lunar surface, returning them safely to the Lunar Gateway.

So under this SLS launch scenario (before the end of 2024),  NASA would have a new simpler and cheaper (and possibly money making) space station at LEO, a new Lunar Gateway at NRHO, plus American astronauts and hopefully, guest astronauts from foreign space agencies, routinely traveling to and from the lunar surface from the Lunar Gateway on private commercial landing vehicles.


Links and References


Space Launch System Lift Capabilities

“Plan D for Outer Space” — NASA updates EM-2 mission baseline

Navigating the twists and turns steering SLS Development

Getting Vulcan up to speed: Part one of our interview with Tory Bruno

NASA updates Lunar Gateway plans

Space Launch System

Deep Space Habitats

Habitat Concepts for Deep Space Exploration


Ares V Launch Capability Enables Future Space Telescopes

Wednesday, November 28, 2018

Mitigating Forest Fires by Harvesting Potentially Hazardous Woodland Biomass for the Production of Renewable Methanol

California Fires 2018 (Credit: David McNew/Getty)


 by Marcel F. Williams

California's forest, woodland areas, and its nearby residents are the latest victims of climate change as the world's fossil fuel dominated energy economy continues to increase greenhouse gasses in the Earth's atmosphere to dangerous levels.   

The state of California has 33 million acres of forest land.  Less than 400,000 of that acreage  burned in California from 1980 to 1990.  But just last year, 1.4 million acres burned in California. And so far this year, 1.8 million acres of California land has  burned.

Why?

California has grown 3 degrees warmer during the autumn seasons over the past 40 years while rainfall in the state has decreased by about one third during the same  period of time.

The  Federal government owns about 57% of the woodlands in California. Privately owned forest accounts for about 40% of California's woodland areas. But the State of California only owns about 3% of Califorinia's forest.

It is currently estimated that California's woodland areas have approximately 129 million dead trees. . Ironically, removing dead trees actually enables the spread of grasses and combustible weeds that make forest more likely to burn. Dry kindling, brush, bushes and twigs are the principal catalyst for the rapid spread of wildfires. So such vegetation also has to be safely managed.

Some of the worst forest fires in California have been caused by power lines. This has prompted some in the state to suggest burying power lines that transverse forested areas. But their are more than 176,000 miles of power lines in California. And putting power lines underground would cost ten times as much as stringing them on poles.

Controlled burning of woodland vegetation has long been a method for fire mitigation since before the arrival of Europeans in North America. But  burning  woodland vegetation would increase the amount of excess carbon dioxide put into the Earth's atmosphere, exacerbating the problem of rising temperatures that have helped to enhance the fire danger in California in the first place.

But  there is an alternative solution that could make the mitigation of forest fires  in California economically sustainable while also reducing California's dependence on fossil fuels. And such measures cold eventually lead California's energy production and use becoming completely carbon neutral.   And all it would  take would be for two legislative measures to pass within the State of California. 

Its my view that the State government in California should pass legislation that:

1. Mandates that  all utilities producing electricity within the State of   California  produce at least 5% of that electricity  for their customers by using-- bio-methanol-- directly derived  from  the dead trees and potentially dangerous woodland biomass in California’s forest and wooded residential areas by the year 2025 and up to  10% by the year 2030

and 

2. Requires all gasoline sold in California to contain at least 5%-- bio-gasoline-- synthesized from bio-methanol that is directly derived from the dead trees and potentially dangerous woodland vegetation in California's forest and wooded residential areas by the year 2025 and up to 10% by the year 2030.

That's it! 

Methanol electric power plant at Point Lisas, Trinidad (Credit: Mendenhall Technical Services)

Approximately 33% of the electricity produced in California is generated by natural gas power plants. About 53% of California's electric power is produced by carbon neutral renewable and nuclear power energy sources.

Its neither difficult nor exorbitantly expensive to modify an existing natural gas electric power plant  to use methanol instead of natural gas. Additionally,  methanol electric power plants would have a higher electric power output than burning natural gas thanks to wood alcohol's  low heating value, low lubricity, and low flash point. 


Gasoline can be blended with methanol up to 15% without any modifications to an automobile. But 
energy companies have been able to synthesize  methanol directly  into high octane gasoline since the 1970s. And this would allow any level of mixing with gasoline from petroleum. In theory, you could have gasoline that is 80% derived from bio-methanol and 10% from petroleum with the remaining 10% of the fuel being composed of ethanol. Such an automotive fuel would be-- 90% derived-- from renewable biomass, reducing the utilization of gasoline from oil by 90%.

Any increases in the cost of gasoline containing bio-gasoline from bio-methanol could encourage Californians to purchase more fuel efficient electric and plug-in-hybrid electric vehicles. But a vehicle fuel mix of 10% ethanol (Federally mandated), 10%  gasoline from bio-methanol, and 80% gasoline from petroleum could substantially reduce oil demand, possibly mitigating any additional cost related to a mandated use of 10% bio-gasoline.

Methanol could also be directly used in high fuel efficiency hybrid fuel cell vehicles. Using methanol directly in automobiles would, of course, be cheaper than converting methanol into gasoline. Bio-methanol derived from California's forest could also be used to produce biodiesel.

There is also a growing global interest in using methanol to power sea vessels. Methanol powered ships would be cleaner and bio-methanol ships  with no sulfur emissions and  lower nitrogen oxide emissions relative to current marine vessels powered by fuels synthesized from petroleum. Marine methanol ferries are already operating between Sweden and Germany.

Legislation mandating the use of bio-methanol from California's forest should provide a strong economic incentive for energy companies selling electricity and gasoline in California to hire forest workers to aggressively harvest dead trees and other potentially dangerous woodland vegetation from California forest and residential woodland areas for conversion into methanol. This should substantially reduce  the level of fire  danger in California's woodland areas while also reducing the amount of CO2 put into the atmosphere as the result of the reduction in forest fire and forest fire intensity.  

Beyond the reduction in fire danger,  hiring people to harvest potentially dangerous woodland biomass  should have a  positive economic impact for nearby residential communities.  Converting at least 10% of the  natural gas power plants in California for methanol utilization should also have some positive economic impact for communities near such energy producing facilities.   And the deployment of  pyrolysis and synthesis facilities designed to convert biomass into methanol within  California should have positive economic impact for the entire state.


Notional Flying Whale airship (Credit: Flying Whales)

The enhanced harvesting of dead trees and potentially dangerous woodland vegetation from remote forest might also encourage energy companies within  California  to utilize the next generation of airship technology. And airships might also greatly enhance the ability of the State of California and the US Federal government to fight fires in California's forest.

Airships being developed by the French company, Flying Whales, are being designed to transport up to 60 tonnes of lumbar within forested areas. Such airship technology could obviously be of use in California for removing the hundreds of dead trees that currently exist in California forest.

Lockheed Martin, on the other hand,  is developing an airship that could transporting payloads up to 20 tonnes in mass within a large cargo bay.  Forest kindling, grass,  bushes, twigs and other potentially dangerous vegetation could be removed from California forest by Lockheed Martin's airships.
 
Similar airship technology could also be used by the State and Federal government to fight forest fires,  dousing woodland fires and residential areas near forest with tonnes of water routinely retrieved from nearby lakes. The Lockheed Martin airships could also be used to rescue residents and fire fighters that might be trapped by raging forest fires.

The aggressive utilization of   airship technology in California could help California businesses to lead the US and the world in  the new age of airships. And, in theory,  such airships could be fueled with dimethyl ether, derived from methanol derived from California's forest  my modifying the diesel engines to use dimethyl ether.

Lockheed Martin airship (Credit: Lockheed Martin)

The introduction of a methanol economy into California could also enhance the ability of the state to become-- completely carbon neutral by mid century. This, however,  would require the production of hydrogen through renewable or nuclear resources--  or a combination of both. Hydrogen could be used to synthesize methanol from wasted CO2 from the pyrolysis of urban and rural biomass  and from the  CO2 waste from the flu gasses of methanol electric power plants.

For California to be completely carbon neutral, all of the natural gas electric power plants in California would have to be converted into methanol power plants. The gradual  conversion of electric power production from natural gas to renewable methanol would make California carbon negative during the transition from fossil fuels to renewable biomass,  with more CO2 being extracted from the Earth's atmosphere  than being returned to the atmosphere. However, once all fossil fuel power plants have been replaced by methanol power plants that recycle CO2 from methanol synthesis and flu gas, then electric energy production and consumption in California would be carbon neutral.

Synthesis of renewable methanol from biomass.

Hydrogen in California could be produced from large solar or nuclear facilities located near biomass pyrolysis plants and methanol electric power plants. Alternatively, such facilities located near California coastlines could liquefy the carbon dioxide, exporting the CO2 by tankers to remote ocean nuclear power or renewable (floating wind, solar, or OTEC) facilities  in remote US territorial waters where methanol and other renewable synthetic fuels could be safely manufactured.  The Exclusive Economic Zones (EEZ) surrounding remote island territories such as: Wake Island, Howland Island, Baker Island, Johnston Atoll, Jarvis Island, etc. could be regions where floating vessels could use carbon neutral energy sources to produce methanol, jet fuel, dimethyl ether, gasoline and diesel fuel far away from urban populations.  Methanol could then be shipped by methanol powered tankers back to the California coastline to fuel its methanol electric power plants or for conversion into renewable gasoline. 

But once the transition from fossil fuels is complete, California energy production and consumption would be carbon neutral. Eventually,  California will have a shortage of bio-carbon resources for its energy economy which would require the extraction of additional CO2 directly from the atmosphere or from seawater or both. 



Links and References


 
Senate Passes Legislative Packagein Response to Wildfire Danger 

Thinning California's fire-proneforests: 5 things to know aslawmakers move toward a plan 
What fire researchers learnedfrom California’s blazes


 Methanol for Power Generation
Methanol as a Low Cost Alternative Fuel for Emission Reduction in Gas Turbines
Methanol - Gaining Twice: Improving Both the Quality of Air as well as Providing a Reliable Electricity Supply

Renewable Methanol as Liquid Electricity

The Methanol Alternative: 2012 Methanol Forum

The Production and Utilization of Renewable Methanol in a Nuclear Economy

Methanol Fuel Blending

The Production of Bio-Methanol

The rise, rise, rise of bio-methanol for fuels and chemical markets

In France, whales soon will fly

Lockheed Martin LMH-1 (P-791)


Monday, October 22, 2018

Evaluating Lockheed Martin's Reusable Lunar Lander and Orbital Propellant Depot Concept

Notional  reusable lunar landing spacecraft on the lunar surface (Credit: Lockheed Martin)

by  Marcel F. Williams 

At the 69th International Astronautical Congress held in Bremen, Germany this month,  Lockheed Martin  unveiled a new reusable lunar crew lander concept.

For simplicity,  I'll designate the notional Lockheed Martin spacecraft discussed in this article as the R-LL (Reusable Lunar Lander).   According to Lockheed Martin, the R-LL will have dry weight of 22 tonnes and be capable of storing up to 40 tonnes of LOX/LH2 propellant. The R-LL will have up to 5 km/s of  delta-v capability.

Lockheed Martin argues that the R-LL should be capable of crewed round trip  missions to any area of  the lunar surface from NASA's future Deep Space Gateway (DSG) which is to be located at a Near Rectilinear Halo Orbit (NRHO).    Such round trip missions, they argue,  would also be capable of delivering up to one tone of payload to the lunar surface in addition to a crew of four individual astronauts. 



While Lockheed Martin has been rather vague about the exact dimensions of the R-LL, they have indicated that it will consist of only two cryotanks and will be derived from the Centaur upper stage family and its descendants. They also suggest that the R-LL will have a diameter close to that of  the future Orion spacecraft.

Since Lockheed Martin's Centaur V is currently in development as the future upper stage for the ULA's future 5.4 meter in diameter Vulcan rocket, one might speculate that the diameter of the R-LL cryotanks might be the same as  and  is supposed to have the same 5.4 meter diameter as the Centaur V. Such large diameter liquid hydrogen and liquid oxygen tanks should be capable of easily accommodating the 40 tonnes of propellant required for the R-LL. So deriving the lunar vehicle from the Centaur V cryotanks might be the simplest and cheapest path towards rapidly developing the R-LL.

Lockheed Martin's Notional  Reusable Crewed  Lunar Landing Vehicle

Propellant: 40 tonnes of LOX/LH2

Inert Weight: 22 tonnes

Engines: Four RL-10 derived engines

Maximum delta-v capability: 5.0 km/s

Maximum number of crew: Four

Additional cargo capability: one tonne of additional cargo
The R-LL would use four engines to provide engine out capability. This would enhance crew safety during attempted landings in case of a serious malfunction with one of its engines. So just two counter balancing engines could be used during a landing in case of single malfunction engine.     Lockheed Martin says that engines for the R-LL  would be derived from  Aerojet Rocketdyne's  RL-10 family or from Blue Origins restartable BE-3 engine. Aerojet Rocketdyne's RL-10 derived CECE engines would be  capable of at least 50 restarts with a throttling range from 104 percent to  just eight percent of thrust. 

Departing from the Deep Space Gateway, it would take approximately 12 hours for the R-LL to reach any point on the lunar surface. Another 12 hours would be required for the R-LL to return to the  gateway at NRHO.

NRHO: (Near Rectilinear Halo Orbit):

Travel time to and  from LEO:~5 days from LEO (3.95 km/s)

Station keeping: 5 m/s per year

Travel time to and from LLO:~ 12 hours to LLO (0.730 km/s)

Lockheed Martin says that their notional lunar spacecraft would be capable of accommodating  a crew of four astronauts on the lunar surface for up to two weeks. Such a lengthy stay would require at least four tonnes of additional shielding mass to protect astronauts from the inherently  deleterious heavy nuclei component of cosmic radiation and from a major solar flare. So one would assume that such enhanced radiation shielding would be part of the notional space vehicle's 22 tonnes of inert mass.

Lockheed Martin has also suggest that propellant depots could be co-orbited with the Deep Space Gateway so that the R-LL can be refueled at NRHO.

The simplest propellant depots would probably have to be utilized within a month after deployment to NRHO since approximately 3.81% of its liquid hydrogen and 0.49% of its liquid oxygen would boil off within a months time. For the 40 tonne LOX/LH2 requirement for the R-LL, such propellant depots would probably have to NRHO by the SLS or the BFR.

More sophisticated propellant depots could be equipped with cryocoolers and solar arrays capable of re-liquefying fuel boil-off.  Ullage gases from the boil-off of liquid hydrogen could be used to re-liquefy gaseous oxygen while 12 to 15 kWh of electricity would be needed to liquefy one kilogram of gaseous hydrogen. The 5.7 tonnes of liquid hydrogen required for a lunar mission would lose more than 217 kilograms of LH2 per month (7.2 kilograms per day).  But a 10 kWe solar  array deployed to NRHO capable of producing more than  240 kWh of electricity per day would be capable of re-liquefying 16 to 20 kilograms of LH2 per day.  The solar arrays for the Orion spacecraft will be capable of producing more than 11  kW of electric power. So it should be rather simple to deploy propellant depots already equipped with cryocoolers and and solar panels in order to prevent fuel boil-off. 

Solar powered depots that simply re-liquefied its ullage gases and powered pumps for storing and transferring liquid fueles would only  require the continuous delivery of liquid hydrogen and liquid oxygen.  Future Vulcan Heavy/Centaur rocket could deliver 7.3 tonnes of liquid hydrogen or oxygen to NRHO per launch. Monthly launches could deliver more than 87 tonnes of propellant to depots located at NRHO per year, more than enough for two R-LL missions to the lunar surface per year.

Notional propellant producing water depot (Credit: Lockheed Martin)
The most technologically complex propellant depots could use solar power to  actually  produce liquid hydrogen and liquid oxygen directly from water. This would require the addition of an electrolysis plant plus substantially more solar power.  A 375 KWE solar array proposed by Lockheed Martin could produce 40 tonnes of liquid hydrogen and oxygen propellant at NRHO per month. Such huge 375 KWE solar arrays would weigh  less than four tonnes. And two such arrays could be directly delivered to NRHO with a single SLS launch. But much smaller commercial launch vehicles could deploy 300 KWe arrays to LEO for later transport to NRHO by fueled upper stages deployed to LEO. 300 KWE arrays at NRHO could produce 40 tonnes of propellant in five or six weeks rather than just four weeks for the larger arrays.

Solar powered propellant producing water depots would make it much simpler and safer for commercial rockets to deliver fuel to NRHO since the payload would only be water. Propellant producing water depots at NRHO could eventually be supplied with water from the lunar poles.

Of course, water and propellant being produced on the lunar surface itself would dramatically reduce the amount of propellant required for   R-LL departures from NRHO. Reusable tanker vehicles directly derived from the R-LL could deliver more than 40 tonnes of lunar water  to propellant producing water depots at  NRHO per flight.  Just 12 round trips from the lunar surface could deliver enough water to NRHO to manufacture enough fuel for crewed missions to the orbits of Mars or Venus.

Lockheed Martin envisions that astronauts would be deployed to the NRHO gateway via the Orion and the Space Launch System. And then the would take the R-LL to the lunar surface and back to the NRHO gateway. And then they would take the Orion back to Earth.

However, propellant depots deployed at LEO  would make SLS crew launches of the Orion vehicle obsolete.  Refueling at LEO, the R-LL would have more than enough delta-v capability to transport crews from LEO to the  NRHO gateway. And refueling at NRHO, the R-LL would, of course, be capable of returning crews from NRHO back to LEO.  And even with  22 tonne of inert weight, a  5.4 meter in diameter R-LL could be launched to Leo aboard a Vulcan/Centaur launch vehicle within  a  6.4 meter in diameter payload fairing.

So for trips to the lunar surface, astronauts would simply take a Commercial Crew Launch vehicle (Falcon9/Dragon or Vulcan/Centaur/CST-100) to a commercial space habitat at LEO where a propellant depot refueled R-LL was already docked and ready to be boarded.  The R-LL would leave LEO with enough  propellant to take its crew on a 5 day journey to the NRHO gateway where another already depot fueled R-LL would already be docked.  The second R-LL  would take the crew for a round trip to the lunar surface, 12 hours to reach the surface and 12 hours to return to astronauts to the Deep Space Gateway.  The astronauts would return to the gateway with the first R-LL already fueled for their return to a commercial space station at LEO. The Crew would than take a Dragon or CST-100 Starliner back to the Earth's surface.

Such an architecture would, finally,  allow the SLS to be used--exclusively-- as a super heavy lift cargo transport. Such payloads could include: large and spacious microgravity and artificial gravity habitats derived from SLS propellant tank technology,  large water and propellant depots derived from SLS propellant tank technology, interplanetary spacecraft capable of accommodating at least 400 tonnes of propellant derived from SLS propellant tank technology for crewed missions to the orbits of Mars and Venus, 8 meter in diameter space telescopes exceeding the capability of the James Webb telescope,  and large inflatable microgravity and surface habitats that could make it a lot more spacious and comfortable for future astronauts and tourist to live under artificial gravity conditions in space or on the hypogravity surfaces of the Moon and Mars.


Links and References

Concept for a Crewed Lunar Lander Operating from the Lunar Orbiting Platform Gateway

Lockheed Martin unveils lunar lander concept

Cis-Lunar Gateways and the Advantages of Near Rectilinear Orbits

Lockheed Martin's Reusable Extraterrestrial Landing Vehicle Concept for the Moon and Mars





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