Launch of Artemis ll

 

 

Trans Lunar Injection Successful!  

 

Links and References

Space Launch System 

 

Where the SLS Comes From

 

Links and References

Space Launch System

NASA Space Launch System Infographics

SLS Derived Artificial Gravity Habitats for Orbital Havens and Interplanetary Space Travel

Notional spinning artificial gravity producing AGH 1500 orbiting 600 km above the Earth's surface. Rectractable solar arrays and radiators produce power and regulate temperatures for the twin habitats.    

by Marcel F. Williams

Microgravity environments are inherently deleterious to human health in space. 

Weight loss, the clumping of perspiration and tears, facial and speech distortions, a degraded sense of  taste and smell,  and even an increased frequency of  flatulence are minor problems associated with short term exposure to a microgravity environment. 

 

But months or years under microgravity conditions can cause much more serious problems for  human health in space. Without regular exercise, 20% of muscle mass can be lost in just 12 days. 1.5% of bone mass is lost in a single month. And this bone demineralization can increase the calcium concentration in the blood stream, increasing the risk of developing kidney stones.  Significant reductions in cardiovascular fitness can also result from long periods of microgravity conditions. Vision problems of varying degrees of severity can occur in men in their 40s or older.  And the use of medicine can be hampered due to the changes in blood flow redistribution under microgravity conditions. 

 

After  a few months aboard the ISS, the blood pressure of some astronauts drops to abnormally low levels when they move from a lying position to a sitting or standing position. Some astronauts even have problems standing up, walking, and turning and stabilizing their gaze.

 

 The deployment of small habitats that are capable of spinning to produce artificial gravity could alleviate the health problems associated with a microgravity environment. Artificial gravity habitats could allow humans to:

1. Remain in orbit perpetually without the need to return to the Earth’s surface reducing the number of launches necessary to maintain a human presence in space 

2.  Remain physically healthy during long interplanetary journeys 

3. Receive quality medical care while in orbit including major surgical procedures. 

4. Have a  permanent human presence in orbit practically anywhere in the solar system 

5. Test  variable levels of gravity on the health of humans and other animal species

Notional 10 meter in diameter AGH 1500 in launch configuration on top of the SLS compared an SLS vehicle with an EUS and 10 meter in diameter payload faring.

 

An SLS Block I configuration would easily be capable of deploying a 60 tonne artificial gravity habitat to LEO. Reusable EUS derived ROTV 100 orbital transfer vehicles cold to deploy the habitat to the appropriate orbit where thrusters could rotate the structure, expanding its  twin counter balancing pressurized habitats at the ends of a 224 meter in diameter  boom. 

 

Directly derived from the SLS oxygen tank architecture, each habitat would be 8.4 meters wide and 16.8 meters tall. This would allow at least five 8.4 meter in diameter habitat levels that are  at least 2.5 meters high, ten human habitat levels in total for the habitat.    This should be enough room to easily accommodate 12 to 32  astronauts and their guest within the twin counter balancing pressurized modules. Because the combined pressurized  area of the twin habitat modules exceeds 1500 cubic meters in volume, the notional artificial gravity habitat is here referred to   as the: AGH 1500 (Artificial Gravity Habitat 1500).

 

AGH 1500 both contracted for trajectory burns and expanded to rotate producing 0.5g of simulated gravity

 

In order to mitigate the physiological effects of Coriolis, the habitat would be approximately 224 meters in diameter, rotating at approximately 2rpm (two rotations per minute) to produce 0.5g of simulated gravity (higher than the gravity on the Moon and Mars).  Slower rotations could be used to simulate the gravity on the Moon, Mars, Mercury, and Callisto, low gravity worlds that could potentially be colonized by humans someday. 

 

 

X-Ray of AGH 1500 showing floors levels on one of the counter balancing pressurized habitat modules

X-Ray of the top or bottom of the microgravity habitat area of the AGH 1500

 

Housed within a ten meter external cylinder would create a 80 centimeter gap between the pressurized habitat. Less than 20 centimeters of water within an external  polyethylene bag or pipes  could provide astronauts on interplanetary journeys with protection against the heavy nuclei component of cosmic radiation and from major solar storm events while also reducing cosmic radiation exposure in general during multi-month interplanetary journeys. 

Permanent artificial gravity habitats located beyond the magnetosphere within cis-lunar space and in orbit around other planets, moons, and asteroids will have to be provided with much more shielding to protect against excessive radiation exposure and potential micrometeorite damage. About 2 meters of lunar regolith would be required to shield the the pressurized habitat. But less than 80 centimeters of space would be available. However, lunar regolith is rich in much denser iron particles   that could be mined and deployed for external shielding.  So only 40 centimeters of lunar iron could be used to permanently shield artificial gravity habitats. Thorium is an even denser lunar material could also be utilized since there appears to be substantial thorium deposits in certain regions on the Moon. 

 

SLS EUS (Exploration Upper Stage) next to a notional EUS derived ROTV 100 (Reusable Orbital Transfer Vehicle +100 tonnes of propellant)

The telescopic boom cylinders are approximately 5 millimeters thick (much thicker that the fuselage for an airplane).  Five cylindrical booms would be  housed within the ten meter in diameter cylinder that accommodates radiation and micrometeorites shielding before the booms are expanded. One centimeter would be added to the top of each cylinder in order for each segment of the boom to securely attach to each other. So 1.5 centimeters would be required for each cylinder. Plus you have to add a centimeter for the boom cable that allows the boom to expand and contract. So ten centimeters would have to be utilized for the telescopic boom. That would allow nearly 70 meters to be used for radiation and micrometeorite shielding. But, as previously stated, only 40 meters or less would be required to permanently shield the twin habitat modules. 

 

AGH 1500 being deployed to a low Earth orbit 600 km above the Earth's surface by an EUS derivied reusable ROTV-100

Reusable EUS derived ROTV 100 vehicles could deploy the AGH 1500 600 kilometers to mitigate frictional drag from the Earth's atmosphere. After refueling at LOX/LH2 propellant depots, two ROTV 100 orbital transfer vehicles could deploy the AGH 1500 to various locations within cis-lunar space: NRHO, DRO, L3, L4, and L5. And twin ROTV orbital transfer vehicles could also deploy the AGH 1500 from cis-lunar space to the orbits of Mars and Venus-- allowing a permanent human presence in orbit above the surface of Mars and the clouds of Venus.

Twin ROTV 100 orbital transfer vehicles deploy an AGH 1500 from lunar orbit to a high Mars orbit beyond the orbit of the martian moon, Deimos

Links and References 

SLS Derived Artificial Gravity Habitats for Space Stations and Interplanetary Vehicles

SLS Fuel Tank Derived Artificial Gravity Habitats, Interplanetary Vehicles, & Fuel Depots

Cosmic Radiation and the New Frontier

Protecting Spacefarers from Heavy Nuclei

The Logistical Viability of an SLS EUS Derived Reusable Lunar Crew Lander

 

NASA Rolls Out Space Launch System

 

 

NASA Successfully Test SLS Core Stage

 

Links and References

Deploying a Ginormous SLS Derived Dry/Wet Workshop Habitat with a Single SLS Launch

SLS Derived Artificial Gravity Habitats for Space Stations and Interplanetary Vehicles

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

Pioneering and Commercial Advantages of Permanent Outpost on the Moon and Mars

 

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

Notional SLS deployed RLV-4 Crew lunar landing vehicle with a crew davit deployment system. 

by Marcel F. Williams

 

Before the end of the decade, the deployment of orbital propellant depots to LEO and NRHO (Near Rectilinear Halo Orbit) will probably make the SLS/Orion vehicle-- obsolete-- as part of an affordable and efficient crew transport  architecture to the lunar surface. So the-- crewed-- SLS/Orion configuration could be haulted just a few years after it started.  

 

However, the four major partners in SLS manufacturing and operations (Boeing, Northrup Grumman, Aerojet Rocketdyne, and Lockheed Martin) could take full economic advantage of the coming  propellant depot architecture by using the Space Launch System to deploy large-- reusable-- lunar landing vehicles into orbit to transport crews or heavy cargo to the lunar surface. 

 

I'll  call such a notional extraterrestrial landing vehicle, in this article, the RLV-4 (Reusable Landing Vehicle Four). And I seriously believe that if Boeing and their SLS partners finance and build a  RLV-4 type of vehicle for both crew and heavy cargo transport to the lunar surface, their partnership could easily end up economically dominating cis-lunar space and probably the rest of the solar system for the next 25 to 30 years-- with such a  simple single stage extraterrestrial vehicle and its inherently useful variants.

LOX/LH2 tank configuration in Boeing's Altair lunar lander concept (Credit: Boeing)

The notional  RLV-4 would be octagon shaped like Boeing's Altair lunar descent vehicle concept. But it will use a simplified propellant tank architecture requiring just two LH2 tanks and two LOX tanks, similar to Blue Origin's octagon shaped Blue Moon lunar lander which is basically a smaller-- simplified-- version of of the Altair lunar lander. 

Top view of LOX/LH2 tank configuration for Boeing's Altair lunar lander concept (Credit: Boeing)

 

The propellant tanks for the RLV-4 will be derived from Boeing's super light weight composite cryotank technology with the two large 3.8 meter in diameter hydrogen tanks and and the two smaller liquid oxygen tanks approximately 2.4 meters in diameter. Both cryotanks will stand nearly 6 meters high within the interior of the RLV-4 octagon. Gaseous compressed hydrogen will be used to pressurize the liquid hydrogen tanks and compressed gaseous oxygen for pressurizing the liquid oxygen tanks during liftoff and trajectory burns-- replacing gaseous helium. Gaseous hydrogen and oxygen will also be utilized for the vehicle attitude thrusters in this notional vehicle design. So hydrogen and oxygen will provide the propellant, attitude control, and tank pressurization for the RLV-4. 

Notional Boeing 3.8 meter in diameter composite LH2 tank and 2.4 meter in diameter LOX tank.

The RLV-4 would be somewhat similar in height with Boeing's Altair concept. But it would be able to store more than twice as much propellant (56 tonnes) thanks to the substantially larger  cryotank diameter of the liquid hydrogen tank and the larger diameter and height of the liquid oxygen tanks relative to those conceived for the Altair. So the RLV-4 would be capable of accommodating up to 56 tonnes of propellant which would be more than enough fuel to land a 16 tonne crew vehicle from LEO to the surface of the Moon.

The restartable engines for the RLV-4 could be provided by SLS partner, Aerojet Rocketdyne, who is currently developing the expendable RS-25 engines for the  SLS core vehicle and the RL-10 engines for the upper stage vehicle. The RL-10 derived CECE engines would be capable of throttling between 104% down to just 5.9% and would be capable of at least 50 in space starts. So the CECE engines should be capable of performing at least 12 round trip missions between NRHO and the lunar surface before having to be replaced. Using them in pairs would give the RLV-4 engine-out capability, enhancing crew safety.

However, the RLV-4 propellant tanks should be capable of at least 50 refills (50 round trips if  missions between NRHO and the lunar surface are conducted on a single fueling of propellant). So if two more engines were added to the RLV-4, 24 round trips could be possible if only two engines were used during a journey-- while propellant flow was shut off to the other pair of engines. Replacing the engines after 24 round trips with four more CECE engines could maximize the RLV-4's reusability allowing the vehicle to conduct up to 48 round trips to the lunar surface before-- if it is refueled less than 50 times. 

Basic RLV-4 cargo lunar lander with solar panels on four sides of the octagon shaped vehicle and radiators on four sides of the vehicle

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 aboard an SLS vehicle within a 10 meter fairing, the RLV-4 could easily fit within the internal  9.1 meter dynamic envelope of the payload fairing. 

 

Notional RLV-4 LOX/LH2 cyotank configuration within the octagon shaped vehicle

While NASA currently envisions only an 8.4 meter fairing for it's use of  the SLS, it would be in the economic interest for the  SLS partnership to quickly develop its originally intended 10 meter fairing in order to have a clear competitive advantage over vehicles like the Space X's future Starship which will have a 9 meter payload bay with probably an 8.1 meter dynamic envelope. However, Blue Origin's 7 meter in diameter New Glenn launch vehicle could be competitive since it should  also be capable of accommodating payload fairings up to 10 meters in diameter. With an 8.4 meter diameter for the SLS core vehicle, the SLS should be capable of accommodating  payload fairing sizes up to 12 meters in diameter with internal dynamic envelopes up to 11.1 meters in diameter.

SLS partner, Lockheed Martin, could supply basically the same Orion derived crew habitat module for the RLV-4 as it will for the Artemis National Team (Blue Origin, Lockheed Martin, Northrup Grumman, Draper) that will deploy a lunar crew lander to the Moon for NASA-- but without the added complexity and the expense of the ascent propellant architecture. 

A tall 10 meter in diameter SLS fairing should  be able to easily deploy two RLV-4 crew vehicles and other variants into orbit per launch-- cutting  RLV-4 deployment cost in half per launch. And the SLS should be able to deploy each vehicle to orbit with enough propellant for each vehicle to self deploy practically anywhere within cis-lunar space.

Utilizing propellant depots deployed at LEO, the RLV-4 should be able to transport crews from LEO to NRHO with less than 24 tonnes of propellant. 

But round trips between NRHO and the lunar surface could require nearly 48 tonnes of LOX/LH2.

Supplying a propellant depot at LEO with enough propellant for a RLV-4 crew mission to NRHO would only require a single Vulcan-Centaur launch (Vulcan-Centaur 562). 

However, supplying water or propellant to depots located at NRHO for a single lunar mission would require eight Vulcan-Centaur launches for the round trip between NRHO and the lunar surface plus an additional  four Vulcan-Centaur launches to NRHO to fuel the return trip of the RLV-4 back to LEO from NRHO. 

So a single lunar mission would require at least 13 Vulcan-Centaur propellant launches costing more than a billion dollars in propellant cost alone for a single mission. But such cost  would still be competitive with architectures that require at least one SLS/Orion launch plus additional commercial launches for a lunar crew missions. 

However, propellant cost for the RLV-4 architecture would fall dramatically once hydrogen and oxygen were being produced on the lunar surface. And that would mean that only a single Vulcan-Centaur propellant launch to LEO would be required for a lunar mission. 

Propellant destined for depots located at NRHO could come from the lunar surface. And a RLV-4 tanker variant could supply nearly 50 tonnes of water or propellant to an NRHO depot per launch from the surface of the Moon, up to 1200 tonnes of water or propellant until its four engines would have to be replaced, and up to 2400 tonnes of water or propellant to NRHO before the entire vehicle would have to be replaced. So two RLV-4 tanker vehicles deployed-- by a single SLS launch-- might be able to deploy 2400 to 4800 tonnes of lunar propellant to NRHO.

Simple solar  powered RLV-4 variants could serve as orbital propellant depots at LEO and NRHO and on the lunar surface.  Each depot could store up to 56 tonnes of propellant plus up to 100 tonnes of water for possibly making propellant.  The appropriate solar arrays for lunar and orbital RLV-4 derived propellant depots could be developed by SLS partner Northrup Grumman which already specializes in developing and deploying extraterrestrial solar arrays. 

By sharing the cost for the development and deployment of the RLV-4, starting in 2021, Space Launch System partners: Boeing, Aerojet Rocketdyne, Lockheed Martin, and Northrup Grumman could have the RLV-4 lunar lander and its variants ready to be deployed within a 10 meter in diameter SLS payload fairing by the year 2027.

By 2030, future RLV-4 passengers (astronauts and tourist) would simply have to take a Vulcan-Centaur-Dream Chaser or another commercial crew configuration to a commercial orbital habitat at LEO-- such as a commercial SLS derived Dry/Wet Shop mega habitat.  At the orbiting habitat,  passengers would transfer to an RLV-4 that has already docked at the habitat and already refueled at a nearby RLV-4 derived propellant depot or another commercial depot. 

It would take the RLV-4 about four days to transport up to 8 people to another private microgravity  habitat located at NRHO which would serve as a gateway to the lunar surface. There, passengers would transfer to another RLV-4 vehicle that was fueled on the lunar surface at a lunar outpost with enough propellant to transport them to the surface of the Moon in just 12 hours time. Or the RLV-4 that they arrived in could be refueled to transport them to the lunar surface. 

The RLV-4 Crew vehicles located at NRHO  could also utilize the cheap lunar propellant exported to NRHO depots for bi-weekly crewed missions to other areas on the lunar surface-- lasting 6 days-- before returning the the NRHO Gateway.  But if two RLV-4 vehicles are available at an NRHO Gateway, then weekly missions practically anywhere on the lunar surface could be conducted by a group of astronauts on a weekly basis.

Once passengers have completed their stay on the lunar surface, lunar propellant could be used to transport them on a four day trip from the Moon all the way back to LEO where they could take a Dream Chaser back to Earth, landing at any accommodating airport or spaceport in America.  

But as advantageous the RLV-4 would be as a commercial extraterrestrial crew lander, it would be even more economically viable as a lunar cargo vehicle for transporting exceptionally large and heavy SLS LEO launched payloads to the lunar surface. The RLV-4 as a heavy cargo vehicle will be discussed in my next article on the Reusable Landing Vehicle IV. 
 
Links and References

 Lunar Lander Vehicle Design Overview

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

System Architecture Design and Development for a Reusable Lunar Lander

Boeing's Composite Tank Could Greatly Improve Launch Vehicles

CECE: Expanding the Envelope of Deep Throttling Technology in Liquid Oxygen/Liquid Hydrogen Rocket Engines for NASA Exploration Missions

 Blue Origin's National Team Lunar Lander

Vulcan-Centaur

Deploying a Ginormous SLS Derived Dry/Wet Workshop Habitat with a Single SLS Launch

Delta V Calculator