Thursday, July 6, 2017

(Part III) A Practical Timeline for Establishing a Permanent Human Presence on the Moon and Mars using SLS and Commercial Launch Capability

A rotating artificial gravity space station in Mars orbit beyond the orbital arc of Deimos. One ETLV-4 crew lander is docked at the station's central docking port while a crewed ETLV-4 approaches the station after visiting the surface of Phobos.


by Marcel F. Williams

Part III: Artificial Gravity and the Moons of Mars 


While traveling from Earth to the Moon or the Earth-Moon Lagrange points only takes a few days, human voyages between Mars and cis-lunar space will require a several months of travel time. So astronauts will have to be adequately  protected from the  deleterious effects of cosmic radiation (especially its heavy nuclei components), solar storms, and the microgravity environment. 

The notional crewed spacecraft proposed under this scenario all have habitat areas that provide at least 20 grams per centimeter squared of radiation shielding, enough to protect astronauts from the penetration of heavy ions and from harmful levels of radiation resulting from major solar events. Such levels of shielding in interplanetary vehicles should limit astronaut radiation exposure to less than 30 Rem per year during the worse cosmic ray conditions (the solar minimum).  Permanently occupied space stations beyond the Earth's magnetosphere and  that rotate to produce a simulated gravity will have their internal shielding (iron plates)  gradually increased until levels of internal radiation exposure for its human inhabitants  is below 5 Rem per year (the legal limit of radiation exposure allowed for radiation workers on Earth). 

In order to mitigate or eliminate the deleterious effects of microgravity, under this architecture, artificial gravity environments (0.5g) will be provided for astronauts for multimonth interplanetary journeys. Simple rotating spacecraft (AGH-I) composed of three pressurized SLS propellant tank derived habitats joined together by cables and twin expandable and retractable booms will be used for interplanetary voyages between EML1 and high Mars orbit. Similar artificial gravity producing habitats will also be used for permanent space stations (AGH-SS) deployed in orbits within cis-lunar space and in orbit around Mars. 


Flight paths between LEO and  EML1 and EML1 and high Mars orbit
NASA is currently contemplating a solar/xenon based interplanetary architecture. The scenario presented here, however,  advocates a propellant depot based interplanetary architecture similar to that advocated by the ULA (United Launch Alliance). The advantages are:

1. LOX/LH2 propellant allows astronauts to reach Mars faster than interplanetary vessels propelled by xenon gas, reducing radiation exposure and the psychological stress of longer travel times.

2. The continuous drive of xenon engines would make it difficult to accommodate artificial gravity habitats, forcing astronauts to endure the deleterious of effects and the physical and psychological stresses associated with a microgravity environment. So multi-month journeys within a microgravity environment could significantly increase that chances of fatal mishaps during an interplanetary mission.
3. Chemical rockets would have the advantage of being able to dump their water shielding just before their final trajectory burns,  substantially reducing vehicle mass as the spacecraft enters high Mars orbit or cis-lunar space. 

4. A xenon based interplanetary spacecraft would be dependent on an expensive fuel that has to be launched out of the Earth's enormous gravity well. A LOX/LH2 producing water depot, on the other hand, could eventually use extraterrestrial sources of water and oxygen from the Moon, Mars, the moons of Mars, etc.  

5. In order to reduce the mass required to be launched from the Earth's gravity well, a xenon based interplanetary architecture would still require substantial amounts of extraterrestrial water for drinking, food preparation, washing, radiation protection, the production of air,  and for the production of LOX/LH2 or LOX/methane propellant for vehicles landing and taking off from the surfaces of Mars or the moons of Mars. So it would be much simpler and cheaper for extraterrestrial resources to be used for the entire architecture instead of just part of it.


Bigelow BA-330 habitat which is inherently provided with enough shielding to protect astronauts from heavy nuclei penetration.


SLS and Commercial Launch Sequences to Establish a Permanent Human Presence in High Mars Orbit

2027

SLS Launches: 

SLS Launch 14: Two CLV-7B (Cargo Landing Vehicle) deployed to lunar outpost after refueling at EML1:

First CLV-7B   will be carrying  a second mobile hydrogen tanker (MHT) derived from the 2.4 meter cryotank technology plus  four  more Water Bug microwave water extraction robots.

Second CLV-7B  will deploy at least 160 KWe of  nuclear power to the lunar surface with at least a 10 year lifetime for the fueled reactors. 

SLS Launch 15: SLS deploys first artificial gravity habitat to LEO (AGH-I). An OTV-125 (an IVF modified EUS) transports the AGH-I to EML1

SLS Launch 16: SLS deploys WPD-OTV-400  EML1. The propellant producing water depot will be capable of storing up to 400 tonnes of LOX/LH2 propellant and up to 1000 tonnes of water.  

SLS Launch 17: SLS deploys OTV-400 to EML1. The SLS propellant tank derived vehicle will be used to transport crews between high Mars orbit and cis-lunar space.  


Commercial Launches:

1. First commercial deployment of reusable ACES-68 (ULA) and Shepard (Blue Origin) derived lunar landing tankers for transporting  lunar water from the lunar surface to EML1 (at least 1000 tonnes to EML1 per year)

2. Commercial launches of twin satellite communications and navigation system to Sun-Mars L4 and L5  plus a trio of satellites into Aresynchronous orbit in order to establish uninterrupted communications between Earth and Mars and between Mars orbit and the martian surface.

Notes:

 1. 2027 will be the beginning of four SLS launches per year by NASA

2. The AGH-I will be provided with water 30 centimeters of internal water shielding from water depots located at EML1. In 2027, the crewed structure will test its ability to provide 0.5 g of simulated gravity and its ability to routinely expand and contract its cables and booms and to increase and decrease its rate of rotation. 

3. The OTV-400 orbital transfer vehicle will be tested by sending it unmanned to Sun-Earth L2 and then back to cis-lunar space. 


SLS propellant tank derived Deep Space Hab (DSH). Requires additional water shielding to protect astronauts from heavy nuclei penetration (Credit NASA)

2028

SLS Launches: 

SLS Launch 18: Two DSH (Deep Space Habitats) deployed to LEO; one remains permanently at LEO while the other will  be transported by an  OTV-125 to EML1 and then to high Mars orbit

SLS Launch 19: Second WPD-OTV-400 to EML1

SLS Launch 20: SLS deploys third WPD-OTV-400 to EML1

SLS Launch 21: SLS deploys fourth WPD-OTV-400 to EML1

Notes:

1. Odyssey 1 (OTV-400 +AGH-1+ETLV-4) will travel to to  SEL2 (Sun Earth Largrange Point 2) in order to test the Odyssey vehicles interplanetary capability. It will take about 30 days to reach ESL2 and 30 days to return to cis-lunar space. 30 days will be spent at SEL2. 

2. LEO DSH (LEO Space Hab) will join the BA-330 as an additional way station for beyond LEO missions for NASA  


SLS propellant tank derived artificial gravity habitat (AGH). Requires 30 cm of water shielding for crewed interplanetary journeys and 50 cm of iron shielding as a permanent space station deployed beyond the Earth's magnetosphere. 

2029

 SLS Launches:

SLS Launch 22: Second AGH-I deployed to EML1

SLS Launch 23: Second OTV-400 deployed to EML1

SLS Launch 24:  Two ETLV-4 + OTV-125 are launched to LEO for redeployment to EML1

SLS Launch 25: Two CLV-7B vehicles deployed to LEO for redeployment at EML1:

Cargo Langer One: mobile magnetic iron extraction robots + 3D iron  panel manufacturing machines for internally radiation shielding AGH-SS space stations.

Cargo Lander Two: regolith bag manufacturing plant to enhance the protection of landing pod areas and for shielding the domed sections of future biosphere habitats

Commercial Launches:

1. Commercial launch of  BA-330 to LEO and transported to EML1 by ACES-68 OTV. The BA-330 will  be transported to high   Mars orbit by an OTV-125; departs in February of 2029 to arrive in high Mars orbit in July of 2029.
Notes:

1. Odyssey 2: Second crewed  mission of the Odyssey spacecraft will be a 235 day  round trip to SEL1 (Sun-Earth Lagrange point 1)

2. With four  WPD-OTV-400 depots at EML1, one will depart for  Mars  in January of 2029 to arrive at high Mars orbit in July of 2029. A second WPD-OTV-400 depot will depart EML1 in February of 2029 to also arrive in high Mars orbit in July of 2029. Both propellant depots will carry at least 550 tonnes of water to high Mars orbit. 

3. OTV-125 transports DSH  to high Mars orbit; departing EML1 in January of 2029 to arrive at high Mars orbit in July of 2029.

LOX/LH2 fueled OTV-400 and EUS derived OTV-125. Both reusable vehicles will use the ULA's Integrated Vehicle Fluid technology for eliminate the need for helium and hydrazine while utilizing ullage gases for attitude control. 

2030

 SLS Launches:

SLS Launch 26: Third OTV-400 deployed to EML1

SLS Launch 27AGH-SS deployed to EML4 for DOD

SLS Launch 28: NASA deploys a second AGH-SS  to EML1. The partially iron shielded artificial gravity space station will  be transported to high Mars orbit by an OTV-400.

SLS Launch 29: Two Ares R-ETLV-4  deployed to EML1+ OTV-125


Commercial Launches:

1. First commercial crew  shuttles to the lunar surface: reusable  Xeus (ULA), reusable Lunar Shepard (Blue Origin)?
 
Notes:

1. Odyssey 3:  Crewed Odyssey mission ( OTV-400/AGH-I/ETLV-4)  to high Mars orbit with a flyby past Venus.  Departs from EML1 in February of 2030, flying past Venus in  July of 2030 and arriving at Mars in January 2031. The AGH-I will replenish its water shield by rendezvousing with one of  the WPD-OTV-400 water depots.   The Odyssey 3 will use one of the WPD-400 depots to refuel with LOX/LH2 propellant in order to depart  Mars orbit in April 2031,  returning to cis-lunar space in December of 2031

During the crew's three months stay in Mars orbit, the crew will use the two ETLV-4 vehicles in Mars orbit to visit the surfaces of Deimos and Phobos. The crew will also visit the  BA-330 storm shelter and the DHS previously deployed to  high Mars orbit 

2. Second ETLV-4 is not transported with the Odyssey vehicle but self deploys itself to high Mars orbit for utilization in the crewed mission, following the same flight pattern as the Odyssey 3. 

Reusable ETLV-4 will allow astronauts to visit the moons of Mars. The ETLV-4 will also be used to transport the the ADEPT attached Ares-ETLV-4 to low Mars orbit for missions to the surface of Mars.


2031

 SLS Launches: 

 SLS Launch 30: Two ETLV-4 + OTV-125 are launched to LEO for redeployment to EML1


SLS Launch 31: OTV-125+ LRH (Lunar Regolith Habitat) to Moon for DOD
 
SLS Launch 32: SLS deploys OTV-125+LRH (agronomy hab) to lunar outpost

SLS Launch 33: Two CLV-7B cargo landers deployed to LEO to be transported to EML1.

CLV-7B One will transport four mobile crew vehicles to the lunar outpost; two for NASA and two for the DOD.

CLV-7B Two will transport two mobile optical telescopes to the lunar surface: one for NASA and one for the DOD



Commercial Launches:

1. Start of commercial launch of ADEPT deceleration shields to LEO by Vulcan launch vehicles. The ADEPT shields will be transported to high Mars orbit by reusable  OTV-125 vehicles and possibly by ACES-68 vehicles.  

 Notes:


1. An OTV-400 will transport the partially shielded AGH-SS to high Mars orbit, departing in February of 2031 and arriving in high Mars orbit in September of 2031.  

2. Second crewed Odyssey mission (Odyssey 4) will be transported to high Mars orbit by another OTV-400. The Odyssey 4 will depart EML1 in March of 2031, arriving in high Mars orbit in August of 2031. Beginning of permanent human occupation of Mars AGH-SS space station

3. Lunar manufactured iron radiation shielding plates for the AGH-SS will be transported to high Mars orbit over the years by several OTV-125 vehicles, decreasing cosmic radiation exposure to less than 30 Rem per year to less than 5 Rem per year during solar minimum conditions. 

4. The two Ares R-ETLV-4 vehicles will rear dock with two ADEPT deceleration shields. An ETLV-4 will dock and transport an Ares R-ETLV-4  from high Mars orbit to low Mars orbit. The unmanned Ares-ETLV-4 will land on Mars, testing the ADEPT shield. Teleoperated robots will be deployed to collect regolith samples and samples of the martian atmosphere. The Ares R-ETLV-4 will return to low Mars orbit where it will be transported by an ETLV-4 back to high Mars orbit. Both Ares-R-ETLV-4 vehicles will be used multiple times,  mating with other expendable ADEPT shields for unmanned sample retrieval missions to the martian surface.  This will also test the reliability of the ADEPT shields for future crewed missions to the martian surface.

5. First DOD outpost on the lunar surface (just a few kilometers away from NASA’s lunar outpost). Mobile crew transport vehicles will be used to transport astronauts between   NASA and DOD facilities.  



Odyssey interplanetary space craft. After trajectory burns to insert the Odyssey into a Mars Transfer Orbit, the AGH-I will separate from the OTV-400 and the ETLV-4 in order to rotate and expand its cables and booms to provide 0.5g of simulated gravity in the twin counter-balancing habitat modules. The AGH will dump its water shield and reattach itself to the OTV-400 and the ETLV-4 for the final trajectory burns into orbit around Mars. 


A Permanent Human Presence in High Mars Orbit

So under this propellant depot architecture, the first crewed mission (Odyssey 3) to high Mars orbit will depart from EML1 in February of 2030 and arriving at Mars in January 2031, flying past the planet Venus during the nearly year long journey. Once the crew arrives, a DSH (Deep Space Habitat) and storm shelter (BA-330) will already be deployed in high Mars orbit in order to enhance their safety. After their orbital transfer vehicles (OTV-400) has been refueled by one of the twin propellant depots (WPD-OTV-400), the Odyssey 3 will depart from Mars in April 2031 and returning to cis-lunar space in December of 2031.

WPD-OTV-400 propellant producing water depot in high Mars orbit refueling an OTV-400 that will transport the Odyssey back to cis-lunar space.


The second crewed mission to high Mars orbit (Odyssey 4) will depart from EML1  in March of 2031, arriving in high Mars orbit in August of 2031. This mission will include the first use of ADEPT deceleration shields to land   R-ETLV-4 vehicles on the martian surface for the robotic retrieval of lunar regolith samples. 
Ares-ETLV-4 simply adds additional thrusters to the top of the ETLV-4 to provide sufficient attitude control while entering the martian atmosphere behind and ADEPT deceleration shield. 


Unmanned Ares-ETLV-4 attached to an ADEPT deceleration shield. Teleoperated robots will be deployed to retrieve regolith and atmospheric samples to be returned to low Mars orbit and back to the AGH-I.



Landing Humans on Mars will be the last part (Part IV) of this article.  
 

Saturday, May 27, 2017

(Part II) Practical Timelines and Funding for Establishing Permanent Outpost on the Moon and Mars using Propellant Producing Water Depots and SLS and Commercial Launch Capability


Twin Lunar Regolith Habitats (LRH) on the sintered surface of a lunar outpost. Surrounding walls are composed of aluminum panels that are automatically deployed while remaining  attached to the side of the pressurized habitat with each panel  joined together by a surrounding envelope of kevlar). The regolith wall is filled to the brim with lunar regolith, protecting astronauts from heavy ions, micrometeorites, and extreme thermal fluctuations, while reducing radiation exposure below 5 Rem per year. Twin habitats are connected to each other by a pressurized  inflatable tunnel.


by Marcel F. Williams
 
Part II: The Moon 

If NASA is provided with $3 billion in annual additional funding from the DOD, as proposed in Part I of this article, then full funding for NASA's cis-lunar  architecture can begin in 2019.  About $1.5 billion annually could be used for the development of unmanned and crewed single staged extraterrestrial landing vehicles derived from Boeing's 2.4 meter in diameter super light weight cryotank technology. Most of the remaining $1.5 billion in annual additional funding could be used for the conversion of the SLS EUS into a solar powered  propellant producing water depots and into spacious deep space habitats and into regolith shielded lunar habitats. 

Additional human spaceflight related funding for NASA will come from charging guest astronauts from foreign space agencies $150 million for every foreign astronauts participating in a beyond LEO mission for NASA. Since NASA's MPCV can carry up to six astronauts and private commercial companies will be capable of transporting up to seven individuals into orbit, NASA could easily accommodate up to three foreign astronauts per beyond LEO mission, saving NASA up to $450 million per flight. 

Substantially  more funding for NASA will be available once funds currently dedicated for Commercial Crew-- development-- are ended in the early 2020s and the ISS program is, finally, ended in the late 2020s.    

The following notional  SLS and private commercial launch sequences present a scenario for establishing a permanent American presence within cis-lunar space and  on the surface of the Moon  by the mid 2020s while also establishing water mining and propellant producing architecture on the lunar surface and a propellant producing water storage systems at LEO and EML1. During the 2020s, under this scenario, SLS flights will be limited to two launches per year once new RS-25 engines are in production.


Nomenclature: 


ACES-68: United Launch Alliance reusable upper stage with BE-3 LOX/LH2 engine

Credit United Launch Alliance

BA-330: Bigelow Aerospace inflatable habitat that will be inherently designed to protect astronauts from heavy ion radiation.


 CLV-7B: Notional cargo landing vehicle that uses seven Boeing 2.4 meter super light weight cryotanks.  With a water bag attached to the top of the vehicle, at least 35 tonnes of water can be delivered to EML1 from the lunar surface. CLV-7B should be capable of being reused at least ten times. 


CST-100 (Starliner): Boeing Aerospace commercial crew capsule. Combined with an ACES-68 and a Cygnus module, the Starliner could  be utilized as a reusable orbital transfer vehicle within cis-lunar space.  

Credit Boeing Aerospace


Cygnus/Orion: Internally mass shielded external habitat Cygnus module for Orion MPCV to protect astronauts from heavy ions during cis-lunar journeys beyond the Earth's magnetosphere  


Credit Orbital ATK


DSH: SLS/EUS deployed microgravity Deep Space Habitat derived from SLS hydrogen propellant tank technology  


Credit NASA
EML1: Earth-Moon Lagrange point 1



EML2: Earth-Moon Lagrange point 2  


ETLV-4: Notional reusable  crew landing vehicle and orbital transfer vehicle utilizing Boeing's 2.4 meter cyrotank technology and the ULA's IVF technology. Five tonnes of water shielding provides a section of the crew area with protection from from heavy ions. Unmanned version (R-ETLV-4) could be used  to deploy small robotic vehicles or cargo to the lunar surface.



EUS: The exploration upper stage would enable the SLS to deploy up to 105 tonnes of payload to LEO or at least 30 tonnes of payload to the Earth-Moon Lagrange points or low lunar orbit. 

Credit NASA


LRH: Notional CLV-7B deployed Lunar Regolith Habitat derived from SLS hydrogen tank technology that automatically deploys a surrounding regolith wall (eight aluminum panels hinged to the side of the pressurized habitat and joined together by an enveloping kevlar sheet ) filled with lunar regolith  2 meters thick, reducing radiation exposure withing the pressurized habitat to less than 5 Rem per year even during solar minimum conditions



MHT (Mobile Hydrogen Tanker):   Derived from three 2.4 meter cryotanks for fueling reusable landing craft with liquid hydrogen.


 MLT (Mobile LOX Tanker): Derived from a single 2.4 meter cryotanks for fueling reusable landing craft with liquid oxygen.

MPCV (Orion Multipurpose Crew Vehicle): Would enable the SLS to be used to deploy astronauts practically anywhere within cis-lunar space and return them safely to the Earth's surface. A radiation shielded Cygnus habitat module would be required to adequately shield astronauts from the deleterious effects of heavy ion radiation. 

Credit Boeing Aerospace


MWT (Mobile Water Tanker): Derived from a single 2.4 meter cryotanks for fueling reusable landing craft with liquid oxygen.



OTV-125: Notional reusable EUS derived orbital transfer vehicle utilizing ULA  IVF (Integrated Vehicle Fluids) technology  would be capable of transferring spacecraft and other payloads up to 90 tonnes in mass from LEO to other regions of cis-lunar space

After NASA


SLS: Space Launch System would be capable of deploying 70 to 105 tonnes to LEO or more than 30 tonnes of payload to the Earth-Moon Lagrange points


Credit NASA
 
Water Bug: Notional mobile robotic vehicle that utilizes microwaves to extract water from the lunar regolith at the lunar poles. 


WPD-LV-7A: Notional  propellant producing water depot derived from seven 2.4 meter cryotanks capable of self deploying itself to the lunar surface after SLS launch into orbit. The WPD-LV-7A would be capable of storing up to 70 tonnes of LOX/LH2 propellant and up to 150 tonnes of water.  

WPD-OTV-125: Notional reusable propellant (LOX/LH2) producing water depot derived from the EUS and utilizing IVF technology capable of storing up to 125 tonnes of LOX/LH2 propellant and up to 200 tonnes of water.


WPD-OTV-125@EML1


Notional  launch sequences utilized to progressively establish a permanent American presence on the surface of the  Moon:


2017

First Space X launch of the Falcon Heavy (up to 54 tonnes to LEO)

2018


First  commercial crew launch of the Atlas V/Centaur/CST-100 (Starliner) by the ULA

First  commercial crew launch of the Falcon 9/Dragon by Space X

1. This will be  the beginning of private commercial crew launches to LEO and  the return of crew launches into space  from American soil and


2019

SLS Launch 1: First NASA test launch of heavy lift vehicle  and  unmanned  Orion/MPCV

First  commercial launch of the Vulcan/Centaur by the ULA (up to 20 tonnes to LEO)

1. This will be the beginning of NASA's heavy lift program 



2020

Commercial launch vehicle deploys first private  habitat  to LEO ( BA-330)

1. This will be the beginning of the deployment of private commercial pressurized habitats to LEO by private commercial spacecraft 


2021 

SLS Launch 2: NASA SLS/EUS deployment of  BA-330 to EML1

SLS Launch 3: First  SLS/EUS  launch of a crew aboard the Cygnus/Orion MPCV to EML1

Commercial Launch:  Satellite  lunar navigation system for NASA and DOD are deployed by commercial launch vehicles to EML1 and EML2 (two lunar navigation satellites to EML1 and two lunar navigation satellites to  EML2)


1. The beginning of two NASA SLS launches per year. 

2. Since the SLS is likely to be assembled and operated by a private company, NASA should give that company the option of being able to utilize an SLS vehicle for at least one private commercial launch per year. Such commercial launches could include the deployment of private commercial microgravity or artificial gravity habitats to LEO or the deployments of habitats to the lunar surface.

3. The first test launch of the EUS for an unmanned mission should enhance the safety of the first crew launch later in the year 

4. Since the BA-330 will have more than 40 cm of shielding, that should be more than enough to effectively protect astronauts beyond the magnetosphere from the deleterious effects of heavy ions and radiation from major solar events. 

5. Lunar navigation satellites will enable NASA and the DOD to deploy payloads to the lunar poles and to communicate with astronauts on the lunar surface at the lunar poles. 



2022


SLS Launch 4: Deployment of  EUS derived  propellant producing water depot (WPD-OTV-125)  plus two ETLV-4 reusable landing spacecraft housed within the large  SLS  payload fairing .

SLS Launch 5: Second  NASA SLS/EUS crew launch of the Orion/MPCV to BA-330@EML1 

Commercial Launch:  BA-330 launched to LEO for NASA by commercial launch vehicle 

1. Beginning of water deposition to depots @ LEO and EML1 by private commercial launch companies for NASA (over 100 tonnes of water delivered to EML1 per year; over 200 tonnes of water delivered  to LEO per year)

2. After producing its own propellant at LEO,  the WPD-OTV-125 depots will transport itself and its detachable solar array to EML1

3. An  ETLV-4 vehicles will be tested unmanned, traveling from  LEO and EML1 where it will refuel to return to LEO

4. A second unmanned  ETLV-4 will also travel from LEO to EML1 but will return with astronauts aboard who initially traveled to EML1 aboard the MPCV .

5. MPCV will remain docked at the BA-330 @ EML1 as an emergency escape vessel

6. DOD astronauts will be launched to their LEO BA-330 LEO habitat by commercial crew launch vehicles 



2023

SLS Launch 6:  Deployment of OTV-125 plus  two tele-operated R-ETLV-4 to LEO (destined for the lunar poles).

SLS Launch 7: Deployment of  second  propellant producing water depot (WPD-OTV-125)  plus two more ETLV-4 reusable landing vehicles.

Commercial Launch: First ULA Vulcan launch with reusable ACES 68 upper stage (up to 40 tonnes to LEO with the addition  solid rocket boosters)

Commercial Launch:  BA-330 launched to LEO for DOD by commercial launch vehicle


1. The MPCV will no longer be used to transport astronauts to EML1. 

2. The two unmanned R-ETLV-4 vehicles will make their first landings at the lunar poles (one to the north lunar pole and the second to the south lunar pole). They will both return to EML1 with regolith samples from both lunar poles less than two weeks after landing. Crewed ETLV-4 vehicles will transport the regolith samples back to LEO and Commercial Crew vehicles will return the crew and lunar samples back to Earth. 

3. OTV-125 will be used to transport heavy SLS payloads (up to 90 tonnes) from LEO to other regions of cis-lunar space.

4. 51 years after the last crewed American lunar landings, American and foreign astronauts  will use two ETLV-4 vehicles to conduct the first crewed mission to the lunar surface, . One ETLV-4 will transport the other ETLV-4 to low lunar orbit from EML1 and then back to EML1 after the other ETLV-4 returns the crew from the lunar surface. A third ETLV-4 will transport the astronauts back to LEO where Commercial Crew vehicles will transport them back to the Earth's surface.

Two reusable ETLV-4 vehicles would be required for crewed sorties to the lunar surface from EML1 and back. But once propellant is being manufactured on the lunar surface, only one ETLV-4 vehicle will be required for missions to the moon and back to EML1.

2024

SLS Launch 8: Deployment of two CLV-7B to LEO and then transported to EML1 by reusable OTV-125: Fueled at the EML1 depot, the first CLV-7B will have an  ATHLETE robot that will deploy electric powered excavation vehicles, sintering vehicles, , backhoe, lifting crane,  to the south lunar pole. The second EML1 refueled  CLV-7B will be used to deploy  four mobile solar arrays with more than one MWe of  total electric power capacity to the South lunar pole.

SLS Launch 9: A  single  CLV-7B to orbit plus a second  OTV-125 orbital transfer vehicle plus a single CLV-7B carrying a Lunar Regolith Habitat (LRH) will be deployed to LEO. The OTV-125 will transport the CLV-7B and the LRH to EML1. Fueled at EML1, the  CLV-7B to deploy a LRH to the already sintered landing area at the lunar outpost at the South lunar pole.


Commercial Launch 1:  BA-330 launched to LEO for DOD by commercial launch vehicle and then transferred to EML1 by OTV-125

Commercial Launch 2: Cygnus/CST-100/ACES deployed to LEO by Vulcan launch vehicle for utilization as a reusable crew orbital transfer vehicle within cis-lunar space

1. Teleoperated mobile microwave robots will sinter areas for landing spacecraft, deploying solar arrays, and for habitat modules, and for propellant depots will be created  

2. Electric powered backhoes will deposit lunar regolith withing the automatically deployed regolith wall surrounding the pressurized habitat providing astronauts with radiation exposure levels less than 5 Rem per year during solar minimum conditions and protection against micrometeorites and radiation from major solar events. 

4. First NASA and DOD astronauts transferred between LEO and EML1 by private commercial  ACES-68/CST-100/Cygnus.  The use of reusable private commercial orbital transfer vehiclees will allow NASA  to use its reusable ETLV-4 vehicles exclusively for crew missions to the lunar surface from EML1.   
  
 5. Reusable teleoperated ACES-68 space vehicles could also refuel at NASA LEO depots in order to deploy satellites to GPS, geosynchronous, and polar orbits. An Delta IV heavy, for instance can only deploy a satellite weighing up 6.7 tonnes into geosynchronous orbit; but it could place four such satellites into low Earth orbit which could later be transferred to GEO by the ACES-68.
 
5. Reusable teleoperated ACES-68 vehicles could also be used to transfer duplicated military satellites to EML4 where the could be safely stored away and monitored and redeployed if a similar satellite is damaged.


2025

SLS Launch 10: Deployment of two Deep Space Habitat (DSH) to EML1 for OTV-125 deployment to EML1(NASA)  and EML4 (DOD)

SLS Launch 11: A second SLS launch will deploy a single  CLV-7B to orbit plus a second  OTV-125 orbital transfer vehicle. Transported by the OTV-125 to EML1, the fueled CLV-7B to deploy a LRH (Lunar Regolith Hab to the lunar surface.

Commercial Launch: BA-330 launched to LEO for DOD by commercial launch vehicle and then transferred to EML4 by OTV-125


1. The DSH will allow NASA to test the integrity of SLS EUS derived pressurized habitats

2. DOD operations at EML4 aboard the BA-330 and DSH will involve the repair and refueling of zombie satellites for later redeployment and the monitoring and testing  of back up satellites located at EML4. If a strategically valuable satellite is destroyed or disabled, back up satellites located at EML4 will be deployed.


2026


SLS Launch 12: SLS deployment of two WPD-LV-7A to LEO. Vehicles refuel at LEO and self deploy themselves to EML1 and then self deploy themselves to the lunar outpost. Alternatively, both vehicles could be transported to EML1 by an OTV-125 before being fueled for lunar deployment.

SLS Launch 13: SLS deploys two CLV-7B to LEO. OTV-125 transports the vehicles to EML1 where they will refuel. One CLV-7B will be carrying a mobile hydrogen tanker (MHT) derived from the 2.4 meter cryotank technology plus  four   Water Bug water extraction robots
the second  CLV-7B will carry two mobile water tankers (MWT), two mobile LOX tankers (MLT


1. The teleoperated Water Bugs will use microwaves to extract and store up to a tonne of water from the lunar regolith at the lunar poles. Teleoperated MWT will be used to extract the water from the Water Bugs and then deposit the water into the WPD-LV-7A propellant producing depots. 

2. Teleoperated MHT and MLT units will extract the liquid hydrogen and oxygen from the WPD-LA-7A depots in order to refuel the reusable ETLV-4, R-ETLV-4, and CLV-7B vehicles.

3. Teleoperated MWT will be used to extract the water stored at  the WPD-LV-7A in order to fill up water bags tied securely on top of the reusable CLV-7B vehicles in order to transport lunar water to the propellant producing water depots located at EML1.


 So, before the end of 2026, under this scenario, thanks to the additional DOD funding ($3 billion annually), NASA will have one BA-330 habitat at LEO and one at EML1. The DOD will also have one BA-330 at LEO, one at EML1, and one at EML4. NASA will also have a DSH at EML1 while the DOD will have a DSH at EML4. And  NASA will also have two habitat modules (LRH) at the south lunar pole, the beginning of America's permanent human presence on the surface of the Moon!


So under this scenario, before the end of 2026, the DOD will have periodically occupied microgravity outpost at LEO and EML1 while NASA will have a water storage and propellant producing  outpost at EML1 and a water producing, storage, and propellant producing  outpost at one of the lunar poles. Such a water and propellant producing extraterrestrial infrastructure should make it relatively easy for NASA to quickly and sustainably expand America's realm to the orbit of Mars, to the moons of Mars, and to the surface of Mars-- using much of the infrastructure developed for cis-lunar space and the surface of the Moon.

 The conclusion of this article (Part III: Artificial Gravity and Mars)  will be posted next week.  


 Links and References

Practical Timelines and  Funding for  Establishing  Permanent Outpost on the Moon and Mars using Propellant Producing Water Depots and SLS and Commercial Launch Capability (Part I)

Reusable Heavy Cargo and Crew Landing Vehicles for the Moon and Mars

The ULA's Future ACES Upper Stage Technology

Protecting Spacefarers from Heavy Nuclei

The Case for a US Miltary Presence at LEO and Beyond

Congress Requires NASA to Develop a Deep Space Habitat

Utilizing the SLS to Build a Cis-Lunar Highway

An SLS Launched Cargo and Crew Lunar Transportation System Utilizing an ETLV Architecture


Tuesday, May 16, 2017

Practical Timelines and Funding for Establishing Permanent Outpost on the Moon and Mars using Propellant Producing Water Depots and SLS and Commercial Launch Capability (Part I)

Two SLS launch vehicles with 10 meter payload fairings. The vehicle to the left will be able to deploy at least 70 tonnes of payload to LEO. The vehicle to the right with its  EUS upper stage will be able to deploy up to 105 tonnes to orbit (Credit NASA). 

by Marcel F. Williams

Part 1: NASA & the DOD


Establishing a permanent human presence on the surface of the Moon is the most  expedient and economical way to eventually  establish a similar permanent human presence on the surface of  Mars. But as  long as NASA continues to spend $3 to $4 billion a year on its big LEO program (the ISS), it is doubtful that the American space agency can adequately  fund its beyond LEO efforts--  without a significant increase in its annual human spaceflight related budget. 


So under this scenario, the ISS program is continued. But starting in 2019,  an additional $3 billion is added to NASA's human spaceflight related budget by the DOD (Department of Defense).  In exchange,  NASA will be committed towards eventually deploying  microgravity and artificial gravity habitats, and lunar and martian surface outpost for the exclusive use and occupation by DOD personal. And such habitats will be derived from similar habitats used my NASA or the private space industries.   

Under this scenario,  DOD funding would also require NASA to provide military astronauts with access to LEO through private commercial spacecraft  and to its beyond LEO habitats either through NASA or private spacecraft.  

So for less than  0.6% ($3 billion) of the annual DOD budget, the ISS program and NASA's beyond LEO program could both be adequately funded while also enabling  DOD personal to have a permanent strategic  presence within cis-lunar space and eventually on the surfaces of the Moon and Mars.

Private American commercial space companies and their astronauts and paying customers will soon  be joining NASA and foreign space agency personal in the New Frontier. So it will be  important for  US companies to know that their investments, hired  personal, and their paying customers will be protected from possible intimidation and coercion from  foreign governments and other hostile organizations. 

The DODs role in space would, therefore, be similar to the role that the US Coast Guard has in America's territorial waters on Earth. And this should prevent  private companies from having to spend money developing  their own private space defense forces  in order to protect their property and personal in space from the  potential hostile  interest from potentially  hostile strategic  competitors such as China and Russia. 

Positions of the Earth-Moon Lagrange Points (Credit: Maccone)

A DOD Earth-Moon Lagrange point presence at EML3, EML4, and EML5 would allow the US military to deposit, protect, and to quickly deploy backup satellites in case US satellites of strategic importance are seriously damaged by terrorist or a hostile foreign power. 

DOD habitats could also be a place for emergency refuge and medical treatment for DOD and NASA astronauts, personal and customers from private space agencies, and for personal from foreign space agencies. So the first extraterrestrial sickbays and hospitals in the New Frontier might be operated by the DOD. So military physicians and nurses might be an important part of the military personal deployed to  all extraterrestrial  habitats under the control of the DOD.

In  2018, Russia intends to charge NASA  $81 million for each NASA astronaut transported too and from the ISS  aboard Russian launch vehicles and spacecraft. Additional funding for NASA's beyond LEO efforts could also come from charging foreign space agencies $150 million for each foreign astronaut participating in a NASA beyond LEO mission.  This could save NASA at least $150 million or more, depending on how many foreign astronauts are allowed to participate in a  beyond LEO mission. NASA could also allow foreign astronauts participating in a mission to the Moon or Mars to  eventually return  to the Earth with up to 10 kilograms  of material retrieved from the lunar or martian surface for their  own space agency's (an absolute bargain) that also helps to reduce NASA's recurring cost for  human missions.  

Part II of this article (The Moon) 

Marcel F. Williams


Links and References

The Case for a US Miltary Presence at LEO and Beyond

Declassified: U.S. Military's Secret Cold War Space Project Revealed (Newly released documents describe the U.S. Air Force's secret cold war project known as the Manned Orbiting Laboratory)

 LUNEX

NASA is paying Russia more than $70 million to bring an astronaut home in this spaceship tonight

Tuesday, April 11, 2017

Reusable Heavy Cargo and Crew Landing Vehicles for the Moon and Mars

Notional ETLV-4 rendezvous with propellant producing water depot @ EML1 with orbiting solar power plant (where propellant depots dock when converting water into LOX/LH2) in the background.
by Marcel F. Williams

In 2018, NASA will launch the first unmanned test flight of its wide body super heavy lift vehicle, the Space Launch System (SLS). That first launch will also test the first uncrewed version of the Orion spacecraft. Coincidentally, 2018 will also be the same year that private companies, thanks to  the  financial help of NASA, will return American astronauts into orbit aboard private spacecraft. Crewed Orion/SLS missions are not scheduled to occur until at least the year 2021.

Congress has directed NASA to reveal the design of a  microgravity Deep Space Habitat (DSH)  by 2018. Unfortunately, the American space agency continues to ignore the use of a DSH as a gateway for crewed missions to the lunar surface while simply ignoring the significant  physiological problems associated with potential multiyear interplanetary missions within a microgravity environment.


Orion MPCV docked @ SLS propellant tank derived Deep Space Habitat (Credit NASA)

 The primary purposes for a  Deep Space Habitat (DSH) should be to:

1. Serve as a gateway to the lunar surface. Astronauts traveling from the Earth or from the lunar surface could dock their spacecraft at an EML1 habitat, taking temporary advantage of the more spacious accommodations before transferring to vehicle fueled destined for the lunar surface.  

2. Serve as a storm shelter during the occurrence of major solar events. This will probably require at least 30 cm of water shielding for the areas within the habitat that the astronauts will be occupying. Major solar events can last for several minutes to several hours.

3. Serve as a maintenance and repair station for reusable lunar shuttles (ETLV) and orbital transfer vehicles. Flex Craft docked at the DSH could also be utilized  for extravehicular repairs to  nearby water/propellant depots and associated solar arrays at EML1.

4. Test the effectiveness of various levels of water shielding required to mitigate cosmic radiation and potentially brain damaging heavy nuclei. In theory, 20 cm of water would be enough shielding to to stop the penetration of the heavy nuclei component of cosmic rays while 30 cm of water would reduce overall  annual cosmic radiation exposure to less than 25 Rem per year during solar minimum conditions. Solar storm events would also be significantly mitigating with 30 cm of water protection. Minimizing the mass of radiation shielding required for safe interplanetary travel would be essential for reducing the amount of propellant required for such missions.

5. Test the integrity and reliability of the pressurized habitat structures that might also be used for habitats on the surface of the Moon and Mars and for rotating  artificial gravity habitats for space stations placed in cis-lunar orbits, Mars orbit, and for crewed interplanetary journeys. 

Of course, a  DSH would be a-- destination to nowhere-- without developing vehicles capable of transporting humans and heavy cargo to the surfaces of the Moon and Mars. And, in my opinion, most Americans and members of Congress will continue to believe that  America's glory years in space are in the past until American astronauts are once again  walking on the surfaces of other worlds-- this time to stay.

NASA's beyond LEO ambitions are severely  hampered by the fact that it continues to operate a relatively expensive (~$3 billion/yr) LEO program (ISS) without a significant increase in the NASA budget for its beyond LEO program. While it has been presumed that much more funding will be provided for NASA's beyond LEO missions once the ISS program comes to an end, there are still efforts to extend the ISS program beyond 2024, again, without increasing the NASA budget in order to pay for its continuation.

Bigelow Aerospace plans to deploy its first private commercial space habitats to LEO  in 2020 aboard the ULA's Atlas V rocket. If this private space company is successful then there's really no reason for NASA to continue the ISS program beyond 2020 since private companies will be able to do  research and development at LEO.   This, of course, would allow NASA to use ISS related funds to develop the cargo and crew landing vehicles, habitats, and related infrastructure for crewed missions to the Moon and Mars.

 Allowing foreign astronauts to participate in NASA's beyond LEO program could provide additional funding for NASA. By 2018, Russia plans to charge NASA,  $81 million per astronaut for transport  to an from the ISS. NASA could charge  foreign space agencies $150 million for each astronaut participating in one of its  beyond LEO missions. The Orion MPCV is capable of accommodating as many as six astronauts. If two of those astronauts were from foreign space agencies paying NASA to join the mission then  NASA could save $300 million per crewed SLS launch.

The Center for Strategic and International Studies (CSIS) has estimated that the cost of developing a crewed two stage lunar lander  at approximately $12 billion. Former NASA director,  Charlie Bolden,  estimated the cost of developing a lunar landing vehicle at approximately $8 to $10 billion.

Neil Armstrong and Buzz Aldrin landed on the surface of the Moon just seven years after NASA invited  eleven private firms  to submit proposals for the Lunar Excursion Module (LEM) in July of 1962. So if we assume that it will take seven years to develop an extraterrestrial landing vehicle or vehicles ( using a COTS type of funding for more than one vehicle), then annual development cost over the course of seven years might range from approximately $1.1 billion  to $1.7 billion. We can also assume that an additional  $1.1 billion a year to $1.7 billion a year over the course of an additional seven years would then be needed to fund the development of a future Mars landing vehicle.  Such annual funding for  extraterrestrial landing vehicles would still leave ample funds for financing the development of lunar and martian habitats and the associated infrastructure.

Boeing Aerospace 2.4 meter Super Light Weight cryotank (Credit Boeing Aerospace)
However, the development time, cost, and recurring cost  for an extraterrestrial landing vehicle (ETLV) could be substantially reduced if: 

1.  A single stage vehicle, or vehicles,  were developed instead of a-- two stage vehicle

2. An ETLV was developed that was largely derived from technology that either already exist or is currently in development

3. An ETLV was developed that utilized LOX/LH2 common bulkhead propellant tanks instead of two different tanks for liquid oxygen and liquid hydrogen

4. An ETLV was developed that were capable of transporting cargo and crews to the surfaces of both the Moon and Mars and back to the orbits of the Moon and Mars

5.  An ETLV was  developed that had pressurized habitat and airlock areas derived from re-purposed ETLV propellant tanks. 

6. An ETLV was  developed that was  capable of being reused for at least for ten round trips to and from their destinations (the surfaces of the Moon or Mars)

7.  An ETLV was  developed that was capable of also being utilized for unmanned robotic and cargo missions

8.  An ETLV was  developed that was capable of also being utilized as a crewed orbital transfer vehicles between LEO, Low Lunar Orbit, and the Earth-Moon Lagrange points

Front view of notional singe stage reusable ETLV-4 derived from 2.4 meter in diameter cryotanks
Side view of notional singe stage reusable ETLV-4 derived from 2.4 meter in diameter cryotanks

ETLV-4 

Up to 40 tonnes of LOX/LH2 propellant in four 2.4 meter in diameter propellant tanks 

Four RL-10 derived CECE engines 

2.4 meter in diameter propellant tank derived central crew habitat area with lower heavy ion shielded storm shelter   

Twin 2.4 meter in diameter propellant tank derived airlocks 

Inert mass without heavy ion water shielded area: ~12 tonnes 

Inert mass with heavy ion water shielded area (22 cm of water): ~17 tonnes 

Gross mass: 57 tonnes 

specific impulse: 445 seconds

   
Due to reduced vehicle mass, reductions in vehicle components, and reduced vehicle complexity, Lockheed-Martin  concluded that the development  cost and recurring cost for a lunar lander could be substantially reduced if a reusable single stage vehicle were developed instead of a two staged spacecraft.   NASA reached a similar conclusion back in the late 1980s when JPL proposed its own single stage LOX/LH2 lunar landing vehicle.  

Boeing developed and tested a 2.4 meter cyrotank as a prelude to its development of a 5.5 meter in diameter, Super Light Weight Tank, that might possibly be used for the 5.5 meter LOX tank for the SLS upper stage (EUS). The 2.4 meter tank was successfully filled with liquid hydrogen chilled at  –423 °F  and cycled through-- twenty-- pressurization and  vent cycles.  If Boeing's 2.4 meter tank were utilized in a common bulkhead configuration for storing LOX/LH2 propellant in an Altair-like vehicle then such tanks could be utilized for a reusable single staged spacecraft. 

Four RL-10 derived CECE (Common Extensible Cryogenic Engine) engines, currently in development by Aerojet Rocketdyne,  could enhance vehicle safety with engine out capability and would be capable of up to 50 restarts. This should enable the vehicle to be used for at least 10 round trips from the surfaces of the Moon or Mars and to various orbital regions near each celestial body.  The CECE engines are also supposed to be designed to have a throttle capability ranging from 104% of thrust down to just 5.6%, which should allow an extraterrestrial landing vehicle to land on worlds as large as the Moon and  Mars or as small as the moons of Mars. However, thrusters near the bottom of an ETLV could also be used to land on the surfaces of the small low gravity martian moons.

Utilizing Integrated Vehicle Fluid (IVF) technology currently being developed by the ULA, helium and hydrazine would no longer be required for an extraterrestrial spacecraft with some ullage gases even being utilized for  attitude control. With the addition of  NASA emerging cryocooler technology, solar powered cryocoolers could reliquify some ullage gases, eliminating the  boil-off of hydrogen and oxygen.

Pressurized crew areas and airlocks derived from re-purposed ETLV propellant tanks, could further reduce development and recurring cost.  The twin cryotank derived airlocks allows more room within the cabin while allowing astronauts to leave the vehicle without having to decompress and then re-pressurize the crew cabin.  With the airlocks positioned just a few meters above the landing pods, pressure suited astronauts could depart the vehicle just few meters above a planetary surface, reducing the difficulty and risks associated with exiting and entering the spacecraft.   The low position of the airlocks should also make it convenient for mobile robotic vehicles to be deployed to the surface of a the Moon or Mars or the moons of Mars for robotic exploration and potential sample  returns to orbit.

NASA's ADEPT deceleration shield concept (Credit NASA)
Developing a  landing vehicle that could be used for crewed missions to both the lunar and martian surfaces would, of course, substantially reduce development cost.  A spacecraft capable of transporting astronauts from surface of Mars to Low Mars Orbit (~4.4 m/s delta-v)  would also be easily capable of transporting astronauts from the surface of the Moon to Low Lunar Orbit or to any of the Earth-Moon Lagrange points (less than 2.6 m/s delta-v).

Landing such an extraterrestrial landing vehicle on the surface of Mars, however, would require the development of a deceleration shield. NASA is currently doing research on two types of deceleration shields: HIAD and ADEPT. The rigid ADEPT deceleration shield could allow spacecraft to deploy up to  40 tonnes of payload  practically anywhere on the surface of Mars. After the ADEPT deceleration shield was discarded, a delta-v of less than 0.6 meters per second would only be required to land the vehicle on the martian surface

 
Notional ADEPT deployment of 40 tonnes of cargo to the martian surface (Credit NASA)

An extraterrestrial landing vehicle capable of transporting astronauts from the surface of Mars to low Mars orbit would also be capable of transporting astronauts from LEO to Low Lunar Orbit or to any of the Earth-Moon Lagrange points. Utilizing the ETLV in such a manner, however,  could make the Orion MPCV obsolete,  allowing astronauts to be transported into orbit by Commercial Crew vehicles and then transferred to a propellant depot fueled  ETLV  for easy access to the Earth-Moon Lagrange points and Low Lunar Orbit and to the lunar surface.
Notional CLV-7B cargo lander derived from 2.4 meter diameter cryotanks

A cargo lander (CLV) derived from the crew version of the ETLV could easily be derived using all seven 2.4 meter in diameter pressurized tanks to carry propellant. With a  diameter of at least 7.2 meters, such a cargo transport could deploy large and heavy structures as large as 8.6 meters in diameter to the surfaces of the Moon and Mars. Pressurized habitats derived from an SLS propellant tank technology with diameters up to 8.4 meters  could easily be deployed to the surfaces of the Moon and Mars by such an ETLV derived CLV. 
ATLETE robots could be used  for offloading heavy cargo to the surfaces of the Moon and Mars aboard a notional CLV-7B (Credit: NASA)



CLV-7B

Up to 35 tonnes of LOX/LH2 propellant in seven 2.4 meter in diameter propellant tanks 

Four RL-10 derived CECE engines 

Specific impulse: 445 second

Inert mass without payload: ~8 tonnes 

Gross mass without payload: ~43 tonnes 

Capable of accommodating cargo with diameters as large as 8.6 meters 

Notional SLS propellant tank derived  regolith shielded habitat for the Moon and Mars with an 8.4 meter in diameter pressurized habitat area that could be deployed to the lunar or martian surface using the CLV-7B and ATHLETE technologies. 

Once the cargo lander is  on the surface of the Moon and after its payload is deployed,  water bags could be securely attached to the top of the  CLV-7B. This could allow the CLV to be reused as a water transport tanker capable of transporting  at least 35 tonnes of water from the surface of the Moon to EML1. Using its CECE engines for ten round trips could enable the CLV to  deliver more than 300 tonnes of water to   propellant producing water depots located at EML1.

With the capability of landing crews and payloads on the Moon and Mars, the ETLV-4 crew lander and the CLV-7B cargo lander should also be capable of  someday landing crews and cargo on the surfaces of the planet Mercury and on Jupiter's moon, Callisto, two other viable worlds for potential commercialization and human settlement. Within Jupiter space, automated unmanned ETLV-4 spacecraft operated from an outpost on Callisto could transport mobile robotic vehicles to the Jovian moons within Jupiter's deadly radiation belt (Ganymede, Europa, and Io) for continuous robotic exploration and sample returns from these interesting but heavily radiation inundated  worlds.


Links and References

Composite Cryotank Technologies; Demonstration


CECE (Common Extensible Cryogenic Engine)


An Integrated Vehicle Propulsion and Power System for Long Duration Cryogenic Spaceflight (ULA)


 The SLS and the Case for a Reusable Lunar Lander

Finally, some details about how NASA actually plans to get to Mars

 

Private Space Habitat to Launch in 2020 Under Commercial Spaceflight Deal


Russia is squeezing NASA for more than $3.3 billion — and there's little anyone can do about it


Apollo Lunar Module


Substantially Enhancing the Capability of the SLS Architecture by Utilizing EUS Derived Propellant Depots and Reusable Orbital Transfer Vehicles


ADEPT Technology for Crewed and Uncrewed Missions to the Planets

 

Landing on Mars with ADEPT Technology

 

Inflatable Biospheres for the New Frontier 

 

Living and Reproducing on Low Gravity Worlds

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