Dream Chaser

First Stage Tank of the New Glenn Heavy Lift Launch Vehicle Revealed

Stoke Reusable Upper Stage

 

 

 Links and References 

 StokeSpace

 

South Korea Places its First Satellites in Orbit

References and Links

Nuri Rocket

 Korea Aerospace Research Institute

Europe Wants a Manned Space Program (Angry Astronaut)

Neutron Rocket Development Update

 

Links and References

Neutron Rocket

Wang Yaping becomes China's first woman to walk in space

Sierra Nevada's Plans for Crewed Dream Chaser Spaceplane and Commercial Space Station

NASA Administrator Jim Bridenstine: A Look Back

Commercial Advantages of a Reusable SLS Deployed Lunar Cargo Lander

Notional RLV-4 Cargo vehicle in a distant  Near Rectilinear Halo Orbit awaiting depot refueling before transporting a multilevel Lunar Regolith Habitat to an outpost at one of the lunar poles. 

 

 by Marcel F. Williams

Privately financing the development of a reusable SLS deployed lunar landing vehicle should be a priority for the major  Space Launch System partners: Boeing, Lockheed Martin, Aerojet Rocketdyne, and Northrup Grumman. A reusable single stage  LOX/LH2 fueled vehicle (RLV-4 Crew) could be commercially successful as a crew lander by simply adding a-- pressurized habitat module-- already being developed by Lockheed Martin for the Blue Origin National Team. 

Notional RLV-4 Crew vehicle with Lockheed Martin derived habitat module with crew deployment davit system.

 

By financing a single stage vehicle rather than a two stage vehicle, development cost could be substantially reduced by simply developing one vehicle instead of two. Further cost reductions could result from using engines and propellant tank technology that already exist. So a notional RLV-4 could use  RL-10 derived CECE engines already developed by SLS partner Aerojet Rocketdyne  and super lightweight composite propellant tanks already developed by Boeing. 

I envision the RLV-4 Crew and RLV-4 Cargo vehicles going into operation by the year 2026. If we assume a development cost of $6 billion for the RLV-4 over the course of six years, then each SLS partner would be required to supply at least $250 million a year of funding for the development of the reusable RLV-4.

Notional RLV-4 Cargo vehicle capable of being filled with up to 56 tonnes of LOX/LH2 propellant.

 

Similar to the RLV-4 Crew vehicle, I envision the RLV-4 Cargo as being launched-- in pairs-- within the 9.1 meter in diameter dynamic envelope of a 10 meter in diameter SLS payload fairing.  At its corners, the maximum diameter of the RLV-4 octagon  would be 8.44 meters with a distance between each opposite 3.23 meter side of the octagon being approximately 7.8 meters. With the legs folded during launch, the RLV-4 could easily fit within the internal  9.1 meter in diameter dynamic envelope of the 10 meter in diameter SLS  payload fairing.  

Each RLV-4 Cargo vehicle would weigh approximately 8 tonnes. The 10 meter in diameter payload fairing would add an additional 10 tonnes in weight headed for orbit.  Since an SLS Block I would be capable of deploying up to 70 tonnes to LEO, up to 44 tonnes of propellant could be added to one of the vehicles in preparation for a mission. 

Alternatively, one RLV-4 Crew vehicle could be launched with one RLV- 4 Cargo vehicle. Before launch, the crew vehicle would be filled with enough propellant to transport a crew to NRHO. The cargo vehicle would simply remain in orbit at LEO until its ready to dock with a payload and be fueled for a mission.

The reusable  RLV-4 Cargo vehicle would be able to dock securely with large payloads (up to 10 meters in diameter) subsequently deployed to LEO by the SLS. Payloads deployed to orbit by the SLS would be equipped with flat standardized docking bases configured to securely join with the octagonal payload floor of the RLV-4. Propellant depots deployed to LEO, NRHO (Near Rectilinear Halo Orbit) and eventually on the lunar surface would be used to fuel and refuel the RLV-4 Cargo vehicles.

Octagon shaped payload floor of notional RLV-4 Cargo vehicle.

 

Fueled at LEO with up to 56 tonnes of propellant, the RLV-4 could deploy up to 10 tonnes of cargo to the lunar surface. Alternatively,  the RLV-4 could transport up to 30 tonnes of cargo to NRHO where it could then be refueled to transport its 30 tonne payload to the lunar surface.

If the SLS deployed payload has an upper attachment area that could allow an additional RLV-4 to dock then two RLV-4 Cargo vehicles could be utilized for a single cargo mission.  This could allow up to 60 tonnes of payload to be transported to NRHO. A single fully fueled RLV-4 Cargo vehicle could deploy up to 50 tonnes of payload to the lunar surface. But two vehicles would be required to deliver a 60 tonne payload to the surface. One vehicle would only travel to lunar orbit and then back to NRHO while the second vehicle would travel to the lunar surface with its 60 tonnes of payload. 

So the reusable RLV-4 cargo system would be capable of delivering 10 tonnes to 60 tonnes of payload from the lunar surface from LEO. And that means the SLS   could deploy up to 60 tonnes of payload to the lunar surface with a single launch if it used a reusable RLV-4 Cargo transport system. 

Notional RLV-4 Cargo deployed lunar crane for unloading large cargo and for lunar regolith deposition. 

Large lunar cranes might be one of the most valuable initial payloads for the RLV-4 Cargo. Using a davit system, a pair of large cranes could be deployed to the lunar surface.  Such electric or hybrid electric (pressurized hydrogen fuel cell/battery) vehicles could be used to unload large and heavy payloads from a large variety of lunar landing craft. If we assume that each lunar crane weighs at least 8 tonnes, lunar regolith could be used to provide an additional 24 tonnes of counter weight. So each lunar crane should be capable of offloading more than 30 tonnes of payload. However, if the iron and other metals that inherently exist within lunar regolith are magnetically extracted to increase the counterweight capabilities of lunar regolith then payloads weighing more than 60 tonnes could be unloaded. Lunar cranes could also be used to deposit regolith within the surrounding walls of large habitats and within the foundation floor for inflatable biospheres and surrounding bio-tori.

RLV-4 Cargo vehicle carrying twin lunar regolith cranes to be deployed to the lunar surface using davit system.

 

Pressurized 8.4 meter in diameter cylinders derived from SLS propellant tank technology could provide multilevel habitats for the lunar surface up to  20 meters tall if deployed within an SLS 10 meter in diameter payload fairing. With a self deploying regolith walls, lunar cranes could provide appropriate radiation shielding by simply dumping lunar regolith within the cavity of the surrounding wall. 

Lunar regolith crane about to remove a Lunar Regolith Habitat from a RLV-4 Cargo vehicle.

But even longer 8.4 meter in diameter cylinders could be deployed to the lunar surface after being to deployed to LEO by the SLS. 40 meter habitats could be deployed to the lunar surface using the RLV-4 Cargo. Such habitats could be unloaded by large  lunar cranes and deployed horizontally to the lunar surface and then covered with lunar regolith bags. The use of the larger horizontal  habitats for agriculture could even allow for the growing of orchard trees for the production of apples, oranges, peaches, lemons, etc. The horizontal habitats could also be used for aquaculture, raising shrimp, crabs, fish, clams, etc. 

X-Ray of an SLS propellant tank technology derived Lunar Regolith Habitat

If the RLV-4 Cargo is used to deploy inflatable Kevlar biosphere and bio-tori then substantially larger habitats could be deployed. 50 meter in diameter  Kevlar biospheres that are pressurized with half the atmospheric pressure on Earth could easily be deployed to the lunar surface by an RLV-4 Cargo.  An additional SLS launch would be required to launch the surrounding  25 meter wide  bio-torus. And another SLS launch would be required to deploy the expandable connecting tunnel and regolith base for the biosphere and bio-torus on top. 

 A 15 meter high  SLS deployed lunar regolith hab might provide five spacious 8.4 meter in diameter habitat floor levels (55 square meters per floor). 

But the bottom half of a 50 meter in diameter biosphere could provide up to 9 habitat levels with each floor averaging about 25 meters in diameter (490 square meters per floor). That would be up to 16 times the floor area for just the bottom half of the biosphere. The upper half of the biosphere (the biodome) would provide the astronauts, military personal, and guest with spacious recreational area with a ceiling up to 25 meters high. Such an area could easily accommodate a large circular recreational swimming pool 30 meters in diameter. This might also be room enough to strap on a pair of wings and fly about within the 50 meter wide biodome.  The surrounding bio-torus or tori could be used for agriculture and aquaculture and storage.

Notional lunar biosphere and bio-torus covered with regolith bags and connected to twin Lunar Regolith Habitats on the sintered surface of a lunar outpost area.

 Once propellant is being produced on the lunar surface, extraterrestrial vehicles like the RLV-4 crew should make it substantially cheaper to travel to the lunar surface after departing the Earth's surface aboard a commercial crew vehicle. If a lunar habitat was deployed to the lunar surface and utilized as a hotel for astronauts, tourist, and military personal, the owners could reasonably charge its guest perhaps $10 million each for a 30 day stay. This, of course, doesn't include the cost of the round trip from Earth to the Moon. If we assumed that an individual habitat was continuously occupied by at least 4 to 8 personal (astronauts, military personal, tourist) then an individual habitat could make between  $480 million to $960 million per year in revenue. With up to 16 times the floor area for the bottom half of a biosphere, a single biosphere/bio-tori complex could make more than $15 billion a year in revenue if it were continuously fully occupied with up to 128 people.   Providing water, food, and air for the lunar guest would be insignificant if such resources are derived from ice and carbonaceous and nitrogenous resources in the lunar regolith at the poles or from similar resources deep within lava tubes. Assuming a minimum 20 year lifetime for such habitats, such SLS deployed facilities should be highly profitable.

Links and References

Commercial Advantages of a Large SLS Deployed Reusable Extraterrestrial Crew Landing Vehicle

Inflatable Biospheres and Bio-Tori for Large Outpost and Colonies on the Lunar Surface

NASA selects proposals to demonstrate in-space refueling and propellant depot tech

Delta V calculator

Dynetics Crewed and Unmanned Lunar Landing Systems

Colonizing Callisto

Chrysler's 1971 Single Stage to Orbit Concept

Falcon 9 Launch and Dragon Docking with the International Space Station

Caroline Kennedy Interviews Jeff Bezos @ JFK Space Summit

 

The Fastest, Safest, and Most Economically Sustainable Way to Return to the Lunar Surface

by Marcel F. Williams

 “I’m taking nothing off the table, and we’re not compromising safety. Anything we don’t need to do we can delay. There’s future launches, there’s future things we can test, but right now, how do we get boots on the moon in 2024?”  (NASA Administrator Jim Bridenstine)

It is now a directive of the Executive Branch of the United States for American astronauts to return to the surface of the Moon by 2024. But the type of transportation infrastructure developed for a US return to the lunar surface could largely determine whether, or not,  America will strategically and economically dominate the Moon, cis-lunar space, and the rest of the solar system.

It is estimated that between 100 million to one billion metric tons (tonnes) of water ice may exist at the Moon's north and south poles. Exploiting polar ice deposits on the lunar surface for the production of rocket fuel is one of the principal arguments for returning to the Moon. Lunar hydrogen and oxygen propellant would make it much easier to send humans to Mars. And lunar propellant and propellant dept technology  could also give astronauts easy access to the surfaces of Mercury and Jupiter's Galilean moon, Callisto, two additional worlds that could be potentially colonized by humans someday. 

Liquid oxygen comprises nearly 86% of the mass of LOX/LH2 propellant and nearly 89% of the mass of water. So even if there were no ice deposits on the Moon, the extraction of oxygen directly from the lunar regolith would provide humans with an almost endless supply of oxygen for utilization as propellant.

So any reusable spacecraft developed to return humans to the surface of  the Moon should also be inherently designed  to utilize potential lunar propellant resources-- once such lunar resources become available. But until lunar ice and regolith resources can be exploited hydrogen and oxygen, or water,  will have to be launched into cis-lunar space from the Earth's surface.

The primary purpose for a Lunar Gateway at NRHO (Near Rectilinear Halo Orbit) is to make it simple and easy to routinely visit the lunar surface from that delta-v bridging location. Yet NASA is currently advocating  a highly complex and inherently more dangerous transportation infrastructure to operate out of the NRHO Gateway. NASA's current gateway transportation architecture requires two or three different spacecraft in order to transport astronauts on a simple round trip between NRHO and the lunar surface. And the elements are not even completely reusable.

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

Lockheed Martin, on the other hand, has proposed a simple--  single stage-- spacecraft that can operate out of NRHO. And its completely reusable. The Lockheed Martin's reusable spacecraft concept is derived from the ULA's future Centaur V and ACES rocket technologies. These cryogenic oxygen and hydrogen fueled upper stages will be used in the ULA' new Vulcan rocket system-- which is supposed to go into operation in 2021.


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


Two of the 22 tonne Lockheed Martin lunar landing vehicles, which I will refer to as the R-LL (Reusable Lunar Lander), could easily be deployed to LEO by a single Block I SLS launch within the 8.4 meter (7.5 meter internal) payload fairing equipped with an extra barrel section.  The notional lunar spacecraft, however, would have to be fueled by propellant depots. But propellant depots would be essential if NASA is really serious about exploiting lunar resources to produce hydrogen and oxygen. So there's no logical reason not to develop cryogenic depots now!

The optimal propellant depot design would be a-- water depot-- that simply uses solar electricity to convert liquid water into hydrogen and oxygen though electrolysis and then into liquid hydrogen and oxygen through cryo-refrigeration. However, much simpler depots could be directly derived from the propellant tanks of  existing  upper stages and could utilize NASA's new helium or nitrogen cryorefrigeration technology.

Propellant could be easily transferred to a spacecraft by docking the spacecraft to the propellant depot, automatically connecting the spacecraft fuel hoses, and then firing thrusters to create simulated gravity through acceleration. Useful acceleration for propellant transfer  can be as little as 0.00004 g.

Both water and propellant could be easily deployed to LEO and NRHO by commercial launch vehicles. The Falcon Heavy should be able to deploy more than 15 tonnes of propellant to NRHO and the future Vulcan Heavy rocket systems should be capable of routinely deploying more than six tonnes of propellant to NRHO per launch.  Monthly propellant launches by each system could deploy enough liquid hydrogen and oxygen to NRHO for at least six R-LL round trips to the lunar surface  per year. NASA only sent astronauts to the moon six times from  1969 to 1972 during the entire Apollo program. 

Lightweight, disposable, propellant tank derived from Centaur 3 LOX tank capable of storing 26 tonnes of liquid oxygen (Credit: ULA)

If the R-LL uses ULA's future IVF technology, then only hydrogen and oxygen would have to be transported to NRHO. However, if the R-LL uses existing Centaur rocket technology then gaseous helium will also have to be deployed to NRHO. While the helium itself would represent less than 2% of the total propellant mass, the tanks needed to deliver the helium to NRHO would be heavy and would require the helium to be  launched to NRHO by a  Falcon Heavy or Vulcan Heavy rocket. But using IVF technology would, obviously, make the R-LL simpler to fuel.

Much larger depots, directly  derived from the ULA's Centaur V or ACES upper stage rockets, could be deployed to LEO with the ability to self deploy themselves to NRHO. Such vehicles could store up to 68 tonnes of LOX/LH2 propellant.  So Falcon Heavy and Vulcan Heavy launches to NRHO could transfer their propellant directly to the large depots for long term storage. Reusable ACES tankers could also transport propellant originally deposited by commercial launchers to LEO to NRHO. This could allow technology such as Boeing's Phantom Express to continuously deploy propellant to LEO that could later be exported to NRHO.

Total mass of a water or propellant  that can be deployed to LEO via daily launch of a single Phantom Express space plane:

Daily - 1.36  to 2.27 tonnes

Monthly - 40.8  to 68.1 tonnes

Yearly - 496.4  to 828.6 tonnes 

Yearly amount of water or propellant that could then be transported by reusable ACES spacecraft to NRHO by a single Phantom Express space plane:  200 to 330 tonnes     

Once lunar water and propellant are being manufactured on the lunar surface then the R-LL could also be used as a reusable lunar tanker. Simply replacing the crew transport module with a water tank,  a single R-LL tanker could transport more than 40 tonnes of water to NRHO from the lunar surface. And after 12 round trips, a single  R-LL tanker could deploy more than 480 tonnes of water to NRHO before its RL-10 derived engines would have to be replaced.

Of course, propellant depots deployed to both LEO and NRHO would also make it easy for reusable spacecraft to travel between LEO and NRHO. So an Orion/ACES spacecraft could eliminate the need of using a super heavy lift vehicle to transport astronauts to NRHO.

Under NASA's current scenario, billions of dollars would be spent developing three lunar elements with one or two of the expensive elements having-- no long term future-- as far as the pioneering of the Moon and the rest of the solar system is concerned. The complexity of a three stage vehicle also enhances the risk to astronauts. And it delays the-- inevitable development-- of propellant depots, a technology that is essential for the exploitation of lunar propellant resources.    

So, under the scenario presented here, the propellant depot and reusable spacecraft architecture designed to return astronauts to the Moon would give NASA and America's launch companies almost complete strategic and economic dominance over cis-lunar space by 2025. And NASA could have astronauts on the surface of the Moon at the south lunar pole before then end of 2024.



SLS and Commercial Launch Scenario for Returning Astronauts to the Lunar Surface by 2024

2020 

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


2021

SLS Block I:   Crewed launch of Orion/SM/ICPS on a trans lunar injection lunar flyby.

Commercial Launch:  Propulsion and Power Bus deployed to LEO for self deployment to NRHO


2022

Commercial Launch: Remaining Gateway elements deployed and assembled LEO

Commercial Launch: Commercial Crew launch to inspect the Gateway before it is deployed to NRHO later in the year


SLS Block I + ICPS upper stage: Two fully fueled ICPS or Centaur V upper stages, or a combination of both  are deployed to LEO for a docking rendezvous with the Gateway at LEO. The two boosters transport the Gateway to NRHO (More Gateway component mass can be transported to NRHO if water for  radiation shielding is transported to the Gateway later by commercial launchers)

Commercial Launch: Two FlexCraft vehicles launched to NRHO Gateway

Commercial Launch: Beginning of commercial launches of water and other supplies to NRHO Gateway 



2023

(Last use of RS-25 engines from the Space Shuttle legacy) 

SLS Block I: Crewed launch of Orion/SM/ICPS or Orion/SM/Centaur V to NRHO Gateway

Commercial Launch: Vulcan/Centaur launch of ACES propellant depot to LEO

Commercial Launch: First commercial launches of  liquid oxygen tankers to LEO

Commercial Launch: First commercial launches of liquid hydrogen tankers to LEO


2024

(New RS-25 engines now being produced and utilized)

SLS Block I: Two R-LL reusable spacecraft launched to LEO utilizing commercial propellant depots at LEO to redeploy to NRHO. Both vehicles are initially used to deploy robotic vehicles to the lunar surface for sample returns. One R-LL goes to the north lunar pole. The second R-LL goes to the south lunar pole.

SLS Block I: Crewed launch of Orion/SM/ICPS or Orion/SM/Centaur V or Orion/SM/EUS to NRHO Gateway

Three members of the Orion crew boards one of the R-LL spacecraft for the first human mission to the south lunar pole. Three other crew members remain at the NRHO Gateway to serve as an emergency rescue team in case the first vehicle experiences a serious malfunction while on the lunar surface.

Commercial Launch: Vulcan/Centaur Launch of ACES depot to LEO to self deploy to NRHO

Commercial Launch: Beginning of commercial deployment of liquid oxygen tankers to NRHO

Commercial Launch: Beginning of commercial deployment of liquid hydrogen tankers  to NRHO

Commercial Launch: Vulcan/Centaur launch of reusable Orion/ACES to LEO  for crew transport between LEO and NRHO using propellant depots



Launch Vehicles that could be used to help return humans to the surface of the Moon

SLS Block IB: 110 tonnes to LEO (operational 2024)
 
SLS Block I + ICPS upper stage: 95 tonnes to LEO (operational in 2020)

SLS Block I : 70 tonnes to LEO  (operational in 2020)

Falcon Heavy: 63.8 tonnes to LEO (currently operational)

Vulcan Centaur Heavy: 34.9 tonnes to LEO (operational 2023)

Delta IV Heavy: 28.4 tonnes to LEO (currently operational) 

Vulcan Centaur: 27.5 tonnes to LEO (operational 2021)


Upper Stages that could be deployed to LEO by an SLS Block I Launch

ICPS: Total mass: 30.7 tonnes; empty mass: 3.49; propellant mass: 27.2 tonnes (currently operational)

Centaur V: Total mass: ~ 46 tonnes; empty mass: ~5 tonnes; propellant mass: 41 tonnes (operational 2021)

ACES:  Total mass: ~ 73.5 tonnes; empty mass: ~ 5.5 tonnes; propellant mass: 68 tonnes (operational 2023)

EUS: Total mass: 140 tonnes; empty mass: 15 tonnes;  propellant mass: 125 tonnes (operational 2024)


With NASA's new super heavy lift capability, America will be able to deploy large and heavy structures (up to 110 tonnes in mass) to LEO with a single launch.  This should enable NASA and private space companies to deploy huge reusable spacecraft with crewed interplanetary capability to LEO.  Single launches of the  SLS will also be able to deploy enormous microgravity and artificial gravity space habitats to LEO with pressurized volumes greatly exceeding that of the International Space Station.

With its propellant depot architecture, reusable ACES spacecraft working alone or in pairs could transport at least 40 to 80 tonnes of payload from LEO to practically anywhere within  cis-lunar space. An reusable EUS that could utilize propellant depots would have substantially more capability.

Cargo landing vehicles directly  derived from the notional R-LL vehicle should be able to land more than 40 tonnes of payload on the surface of the Moon.

Finally, by using commercial spacecraft to reach LEO,  a propellant depot architecture could  allow astronauts and tourist to easily travel between NRHO and LEO. This would make it unnecessary to launch astronauts to NRHO aboard a super heavy lift vehicle that is only infrequently used to launch passengers.  At the Gateway, single stage reusable vehicles could be used to travel between the lunar surface and NRHO.   And suddenly private commercial space tourism could expand beyond LEO-- all the way to the practically any place on the surface of the Moon.  And a new economic age of space travel will have begun!




Links and References

Bridenstine says “nothing off the table” as NASA develops new lunar plan 

How Much Water Is on the Moon?

Cis-Lunar Gateways and the Advantages of Near Rectilinear Orbits

Work begins on rocket engines for SLS flights a decade from now

Realistic Near-Term Propellant Depots: Implementation of aCritical Spacefaring Capability 

Status of Power and Propulsion Element (PPE) for Gateway

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

ACES Stage Concept: Higher Performance, NewCapabilities, at a Lower Recurring Cost

ULA’s Vulcan Rocket To be Rolled out in Stages

ULA's Tory Bruno (Twitter)

A Commercially Based Lunar Architecture

Evolving to a Depot-Based Space Transportation Architecture

A Study of CPS Stages for Missions beyond LEO

LARGE SCALE CRYOGENIC STORAGEWITH ACTIVE REFRIGERATION

Transient Modeling of Large Scale Integrated Refrigerationand Storage Systems

NASA Adminstrator's Speech on Returning to the Moon at the Space Symposium

Cis-Lunar Gateways and the Advantages of Near Rectilinear Orbits

Computer illustration of Near Rectilinear Orbits between EML1 and EML2 (Credit: NASA).

NASA appears to have settled on a Near Rectilinear L2 Halo Orbit (NRO) for its future Deep Space Habitat (DSH).  NROs are a subset of of L1 or L2 halo  orbits. NRO's have  large amplitudes over either the north or south lunar poles with shorter periods that pass closely to the opposite pole. Station keeping at an NRO would require a delta-v of only 5 m/s per year. With an impulsive departure from LEO at about 3.124 km/s, a crewed spacecraft would reach an L2  NRO in about 5.33 days. Orbital capture would require a delta-v of 0.829 km/s. 

An  EML1 location for a DSH  would only require a delta-v of  3.77 km/s and four days of travel time. But 2 days of travel time would be required for a journey from EML1 to Low Lunar Orbit (LLO). An NRO location, however, would only require 12 hours of travel time to LLO. So the surface of the Moon could be accessed from a NRO located Deep Space Hab in just 12 hours.


Possible Cis-Lunar Locations for a DSH (Deep Space Habitat)

EML1(Earth-Moon Lagrange Point One):


Travel time to and  from LEO:  ~4 days (3.77 km/s)

Station keeping: < 10 m/s per year

Travel time to and from LLO: ~ 2 days (0.750 km/s)


EML2  (Earth Moon Lagrange Point Two):


Travel time to and  from LEO:~ 8 days from LEO (3.43 km/s)

Station keeping < 10 m/s per year

Travel time to and from LLO:~ 3 days to LLO (0.8 km/s)


DRO (Distant Retrograde Orbit):
 

Travel time to and  from LEO: ~ 6 days

Station keeping: 0 m/s per year

Travel time to and from LLO: ~ 4 days  (0.83 km/s)


NRO: (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)




Significantly shorter flight times from LEO to NRO could be achieved with higher delta-v levels that could easily be achieved by future reusable LOX/LH2 fueled spacecraft such as the ULA's XEUS and Lockheed Martin's MADV which could be used for round trip journeys to the lunar surface from a NRO and for transporting crews between LEO and NRO.


Links and References 
 

Options for Staging Orbits in Cis-Lunar Space 

NEAR RECTILINEAR HALO ORBITS ANDTHEIR APPLICATION IN CIS-LUNAR SPACE

TARGETING CISLUNAR NEAR RECTILINEAR HALO ORBITS FORHUMAN SPACE EXPLORATION

 Human Lunar Exploration Architectures


 

 

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

Notional MADV on the surface of Mars (Credit: Lockheed Martin)

by Marcel F. Williams

 At the 68th International Astronautical Congress, held in Australia last September, Lockheed Martin  unveiled a remarkable new extraterrestrial spacecraft concept.  The single staged space vehicle would be capable of landing either  unmanned or crewed on the surfaces of the Moon or Mars. The MADV (Mars Ascent/Descent Vehicle) would be a propellant depot dependent spacecraft fueled with liquid oxygen and liquid hydrogen. And the MADV would be capable of transporting four member crews to the surfaces of the Moon or Mars. 

MADV (Mars Ascent/Descent Vehicle)

Propellant: 80 tonnes of LOX/LH2 

Inert weight: 30 tonnes 

Engines: 6 RL-10 engines

Maximum delta v capability:  6.0 km/s

Crew: Up to four astronauts

Notional MADV on the polar surface of the Moon (Credit: Lockheed Martin)

After landing on the lunar or martian surface, crews would utilize an electric powered lift located on the vehicle's leeward side to access the surface from the pressurized crew cabin.  Located between its six RL-10 engines, near the bottom of the vehicle, a retractable equipment lift would be lowered to deploy mobile vehicles and other equipment for use on the surface.

However, the MADV's  high delta-v capability (6 km/s)  could also allow the spacecraft to be used as a crew transport  within cis-lunar space. Utilizing pre-deployed propellant manufacturing water depots at LEO and EML1, the MADV could easily transport crews between LEO to EML1-- even with the addition of a  crew hab (10 to 20 tonnes in mass)  with  protective shielding against heavy ions. 

Notional MADV on top of an SLS Block IB (Credit: Lockheed Martin)

 MADV Capabilities

1. Unmanned lunar lander for deploying mobile robotic vehicles and unmanned sample returns

2. A crewed lunar lander capable of traveling to the lunar surface and back to the propellant depots and Deep Space Habitats located at EML1-- on a single tank of fuel

3. Unmanned Mars lander for deploying mobile robotic vehicles for unmanned sample returns from the martian surface.

4. A crewed Mars lander capable of traveling from low Mars orbit to the martian surface and back to low Mars orbit-- on a single tank of fuel.

5. If fueled from a depot in high Mars orbit, it could land directly on the martian surface for Mars outpost operations.

6. If refueled from a depot near an outpost on the martian surface, the MADV could transport its crew all the way to a permanent habitat stationed in high Mars orbit.

7. A crewed orbital transfer vehicle capable of transporting astronauts from propellant depots located at  LEO to propellant depots located at any of the Earth-Moon Lagrange points or in  low lunar orbit.

8. The SLS Block IB could be utilized to transport the MADV to LEO with enough fuel to deploy  itself anywhere within cis-lunar space (EML1, EML2, EML4, EML5, Low Lunar Orbit).

9. An SLS launched  MADV could also arrive at LEO with  enough propellant to transport itself all the way to propellant manufacturing water depots located in high Mars orbit.

Notional landing and take-off of the MADV to and from the surface of Mars (Credit: Lockheed Martin)

Maximum Delta-V Budget for the MADV (6.0 km/s)

Cis-Lunar Space Delta-V

LEO to EML1 (~2 days) - 4.41 km/s

LEO to EML1 (~4 days) - 3.77 km/s 

EML1 to or from LLO - (~2 days) - 0.75 km/s

EML1 to or from LLO - (~3 days) - 0.64 km/s

LEO to  LLO (~2 days) - 4.5 km/s

LEO to LLO (4 days) - 3.97 km/s

LLO to or from the Lunar surface - 1.87 to 2.2 km/s

Mars Delta-V

LMO (500 km circular orbit) EDL to Martian surface - 1.27 km/s

Mars surface to LMO (500 km circular orbit)  - 4.2 km/s

HMO to or from  LMO - 1.4 km/s

HMO to Martian surface via 500 km circular orbit - 2.67 km/s

Mars surface to HMO - 5.6 km/s

LEO to HMO - 5.2 km/s

LEO- Low Earth Orbit, EML1 - Earth-Moon Lagrange Point 1, LLO- Low Lunar Orbit, HMO - High Mars Orbit, LMO - Low Mars Orbit, EDL - Entry, Descent, and Landing


The development and deployment of the MADV still wouldn't negate the need for large unmanned cargo landing vehicles for the Moon and Mars. Such landing craft would be needed to deploy large and heavy habitats, vehicles and other large structures  to the surfaces of the Moon and Mars and, eventually, to other worlds within the solar system.

But  a single stage extraterrestrial landing vehicle such as the MADV should be faster and cheaper to develop than previous two stage crew concepts for the Moon and Mars. So Lockheed Martin's  MADV could be a game changer as a reusable extraterrestrial vehicle capable of using a propellant depot architecture within cis-lunar space and beyond.  And with its high delta-v capability, the MADV could also be the landing vehicle of choice for conveniently transporting humans to the surfaces of the Moon, Mars, Mercury, Callisto, and possibly even Saturn's moon,  Titan, during the rest of the  21st century.   

Links and References

Mars Base Updates and New Concepts

Lockheed Martin Mars Lander Ship Concept (Video)

 Lockheed Martin Adds Lander to Mars Base Concept

On Orbit Refueling: Supporting a Robust Cislunar Space Economy

Mars Base Camp (Video)

NASA's Nuclear Thermal Rocket Concepts

Links and References

Space Technology Game Changing Development Nuclear Thermal Propulsion (NTP)

Nuclear Rockets to Mars (The 1960s)