Tuesday, May 10, 2022

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

Notional reusable EUS derived REUS-LV/Crew vehicle descending to the lunar surface using side thrusters for the final descent and soft landing
by Marcel F. Williams

The current development of the Exploration Upper Stage (EUS) for NASA's Space Launch System offers Boeing Aerospace an opportunity to produce reusable variants of the spacecraft that could greatly enhance the capability of Boeing's super heavy lift vehicle system. 


 Reusable Lunar Crew Lander

By simply adding a pressurized crew module at the top of the spacecraft and landing gear at the bottom of the vehicle could allow the EUS to land humans on the surface of the Moon. I will refer to this notional crew landing EUS variant as the REUS-LV/Crew. 

Replacing gaseous helium with gaseous oxygen and hydrogen for pressurizing liquid oxygen and liquid hydrogen tanks should  allow the REUS-LV to be reused at least 50 times. The gaseous hydrogen and oxygen could also power thrusters for attitude control.   However, with  RL 10 engines capable of only 50 starts, reusability for such a vehicle might be limited to only six round trips between  LEO and the lunar surface.   


Artist depiction of an expendable  EUS for the Space Launch System (Credit NASA)

NASA is intent on establishing its deep space Gateway at an NRHO (Near Rectilinear Halo Orbit), a seven day polar orbit around the Moon. The  human occupied Gateway habitat  would allow 12 hour trips to the lunar surface every seven days.  A weeks stay on the lunar surface would also allow a return to NRHO in just 12 hours time. 

Assuming a dry mass of 23 tonnes for a crewed version of the REUS-LV, the space vehicle should be cable of round trips to the lunar surface utilizing less than 70 tonnes of propellant. So substantial amounts of additional payload could be deployed with crewed missions to the Moon if 113 tonnes of the vehicle's total fuel capacity is utilized.   

Private commercial launch vehicles could transport passengers to the  REUS-LV/Crew spacecraft orbiting independently  at LEO or docked at a LEO orbiting space station. 


Notional reusable REUS-LV/Crew landing vehicle for lunar operations

Once the REUS-LV/Crew vehicle is on the Moon, a davit crane system could be used to lower astronauts, vehicles, and other equipment to the lunar surface and to retrieve astronauts and lunar material later for transport back to the NRHO Gateway. Solar panels positioned on four of the walls surrounding the LOX tank would provide electricity for the crew module plus electric power to keep the hydrogen and oxygen liquefied using the thermal radiators to assist its cryocooler refrigeration systems. 


Orbital Propellant Depots

Two REUS-LV/Crew vehicles could be deployed to LEO with a single SLS launch. But propellant depots would be required to fuel the vehicles at LEO and at NRHO in order to conduct crewed missions to and from the lunar surface and to return the spacecraft back to LEO. So the deployment of two propellant manufacturing water depots at LEO and at NRHO would be necessary for crewed lunar missions. 

Two REUS derived vehicles (REUS-OTV/Depot) could be utilized as propellant producing water depots capable of storing up to 150 tonnes of water for the production of  113 tonnes of LOX/LH2 propellant. 9 tonnes of water contains approximately 8 tonnes of oxygen and one tone of hydrogen. But only 7 tonnes of propellant could be manufactured from 9 tonnes of water since rocket fuel would require a ratio of 6 tonnes of oxygen per ton of hydrogen.   So each depot would be capable of storing approximately 16 tonnes of LH2 plus 97 tonnes of LOX) while wasting 32 tonnes of liquid oxygen. 

However if only 113 tonnes of water is converted into 97 tonnes of liquid oxygen and 13 tonnes of hydrogen then 100% of the water could be utilized as fuel if an  REUS-LV vehicle initially arrives at LEO from Earth with at least 3 tonnes of liquid hydrogen propellant. Two REUS-LV/Crew vehicles would only weigh 46 tonnes. And with an additional six tonnes of liquid hydrogen propellant, would still only be 52 tonnes of payload mass for a basic SLS vehicle capable of deploying at least 70 tonnes to LEO. Fully fueled with LH2, the first REUS-LV/Crew vehicles launched to LEO could require no liquid hydrogen from the LEO depot at all, only its liquid hydrogen.

Water could be continuously supplied to propellant producing depots at LEO by various private American launch systems (Space X, the ULA, and Blue Origin) who have vehicles  that are either currently operational or are very close to being operational: 

Falcon Heavy (Space X) - 63 tonnes to LEO

New Glenn (Blue Origin) - 45 tonnes to LEO

Vulcan-Centaur (ULA) - 27 tonnes to LEO


During the first SLS launch of two propellant depots to LEO, private launch companies could supply one depot with enough water to produce propellant that can be transferred to the second depot to deploy itself plus its solar array to NRHO. 

EUS derived propellant producing water depot approaching orbiting solar power plant @ NRHO where it will use photovoltaic power to electrolyze water into LOX and LH2.
Private launch vehicles could also be used to deploy water directly to NRHO once the propellant producing depot arrives. But it would be much cheaper and efficient for private launch companies to simply focus on supplying water to LEO.  Large reusable REUS-OTV (Orbital Transfer Vehicles) could transfer water from LEO to depots located at NRHO much more efficiently.  A single SLS launch would be required to deploy two such EUS derived vehicles into orbit probably with their LH2 tanks already filled with liquid hydrogen.

REUS-OTV plus optional  interstage connection ring for joining two OTV vehicles together. Such vehicles could be used to transport 60 to 120 tonnes of water and other  payloads between LEO and NRHO and to various lunar orbits and Earth-Moon Lagrange points.

Crewed Missions to the Moon and Reusability
For crewed missions to the lunar surface, An REUS-LV/Crew vehicle  would be fueled with propellant at LEO and then travel  four days  to the orbital outpost at NRHO. After arriving at NRHO, the REUS-LV/Crew vehicle would then be fueled with additional propellant at   for its round trip journey to the lunar surface and then back to NRHO. Once the crew returns to NRHO, only the minimum amount of propellant would be required to return the REUS-LV/Crew spacecraft back to LEO. 
Reusable REUS-LV/Crew vehicle docked at a notional single launch SLS derived MegaStation at NRHO. The notional EUS derived vehicle would be cable of round trips between NRHO and the lunar surface on substantially less than a full tank of LOX/LH2 propellant.   REUS-OTV vehicles could be used to deploy the habitat modules and the pressurized spent SLS core stage from LEO to NRHO.
RL-10 engines can be manufactured with a capability of 50 restarts. So a single REUS-LV/Crew vehicle should be capable of at least 6 round trips to the lunar surface starting and returning to LEO. The REUS-LV/Crew vehicle would be capable of  12 round trips if the spacecraft  is only utilized for trips between NRHO and the lunar surface. 

Two reusable REUS-LV/Crew vehicles could be deployed to LEO with a single SLS launch. And each vehicle deployed would be capable of at least 12 round trips between LEO and NRHO. So a single SLS launch could allow 12 round trips to the lunar surface-- if water can be supplied to LEO and then to NRHO. This would require two more SLS launches to deploy two solar powered propellant depots and two REUS derived orbital transfer vehicles (REUS-OTV) to transport water from LEO to NRHO. So three SLS launches would be required for 12 round trips to the lunar surface (four potential round trips to the lunar surface per SLS launch). 

Lunar Depots

REUS derived propellant producing water depots with landing gear could also be  deployed to the lunar surface with photovoltaic solar power units. If water ice resources are exploited at the lunar poles then propellant could be produced on the Moon. The REUS-LV/Crew vehicle could be fueled with propellant at LEO and travel directly to the lunar surface. And the same REUS-LV/ Crew could later be fueled with lunar propellant for its return trip directly to LEO. 

Reusable REUS-LV/Crew vehicle docked at a notional single launch SLS derived MegaStation at NRHO. The notional EUS derived vehicle would be cable of round trips between NRHO and the lunar surface on substantially less than a full tank of LOX/LH2 propellant.   REUS-OTV vehicles could be used to deploy the habitat modules and the pressurized spent SLS core stage from LEO to NRHO.

 Alternatively, propellant from Earth could be substantially reduced for lunar missions if tankers supplied water from the moon to NRHO depots. REUS-LV/Crew vehicles could then return to LEO using LOX/LH2 propellant produced on the Moon. 


Reusable Lunar Hopper  


The delta-v and travel times for possible crewed suborbital hops on the lunar surface. Fueled with liquid hydrogen and oxygen at a lunar base, a notional REUS-LV/Crew vehicle would be capable of traveling to any region on the surface of the Moon in less than an hour and return back to the lunar outpost on less than  a single tank of fuel.


Supplied with propellant on the lunar surface, the REUS-LV/Crew could also be used as a lunar hopper that could travel to any region on the surface of the Moon in less than an hour. The vehicle would also carry enough fuel to return to the lunar outpost where it was fueled in less than an hour.  With four trajectory burns for each round trip, each REUS-LV/Crew vehicle could travel to 12 regions on the lunar surface. So a single SLS launch could potentially explore 24 regions on the lunar surface if REUS-LV/Crew vehicles are refueled with lunar propellant. 


Repurposing Decommissioned Landing Vehicles 

REUS derived vehicles could still be put to good use after they are decommissioned from their original task.  REUS-LV/Crew vehicles that are no longer safely capable of crewed flights could  be repurposed for storing substantial quantities of water mined from the lunar ice and for storing sewage accumulated from the inhabitants of lunar outpost. With both a hydrogen and oxygen tank, substantial quantities of  water and sewage could be stored in the two different tanks of one vehicle.   The decommissioned vehicles could also be used to store excess oxygen from the production of propellant. LOX and LH2 could be stored in decommissioned spacecraft to produce electric power during the lunar night using fuel cells. Such fuel cells would not only produce electricity from the hydrogen and oxygen-- but also water. 

Decommissioned vehicles could also be used as temporary outpost in lunar regions of particular interest. They could be transported to their lunar locations by electric powered lunar cranes. And regolith bags could be deployed around the vehicle's habitat modules for additional protection against cosmic radiation and micrometeorites. 

Decommissioned REUS-OTV vehicles in orbit could be used in a similar fashion at NRHO for  storing water, or excess oxygen from the production of propellant. 

Deep Space Robotic Missions to Phobos and Deimos

At NRHO, the  REUS-LV/Crew vehicle could also be used for-- unmanned-- round trip  robotic missions to the moons of Mars. The delta-v requirements for such round trip missions between NRHO and the martian moons  would actually be less than round trip missions between NRHO and the lunar surface.  So a robotic REUS-LV would be fully capable of traveling to the surface of Deimos or Phobos and returning to NRHO with substantial quantities of rocks and regolith from those two tiny martian moons.  Roving vehicles could also be left behind that could be used to extensively explore each of the martian moons. The REUS-LV davit system could easily lower and retrieve such vehicles after landing on those tiny worlds.


 Links and References

Rocket to the Moon: What Is the Exploration Upper Stage?

Exploration Upper Stage

EUS on the Moon

 RL 10 Engine

 CECE: A Deep Throttling Demonstrator Cryogenic Engine
for NASA's Lunar Lander

Cis-Lunar Gateways and the Advantages of Near Rectilinear Orbits

Realistic Near-Term Propellant Depots: Implementation of a
Critical Spacefaring Capabilit

Large-Scale Demonstration of Liquid Hydrogen Storage With Zero Boiloff for In-Space Applications

Delta-v Calculator

Delta-v Budget

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

Travel on Airless Worlds

Reusable Hoppers and Orbiters for Rapid Lunar Transportation and Exploration

Monday, April 4, 2022

Higher Levels of Racism and Prejudice Associated with a Disbelief in Human Evolution

Homo erectus pekinensis

According to University of Massachusetts Amherst research published in the Journal of Personality and Social Psychology, a  disbelief in human evolutionary biology in the US was associated with higher levels of racism and prejudice including  support for discriminatory behavior against immigrants, people of African ancestry,  and the LGBTQ community. Similar patterns of racism and prejudice have also been associated with lack of belief in human evolution by individuals living in Europe and in the Middle East.

Links and References

Bigotry and the human–animal divide: (Dis)belief in human evolution and bigoted attitudes across different cultures.

Disbelief in human evolution linked to greater prejudice and racism

Thursday, January 27, 2022

Monday, January 3, 2022

Crime & Punishment

Living facilities in a California State Prison(Credit Wikipedia)

by Marcel F. Williams

Per capita, most victims of crimes are people of color. Just check the stats. So simply allowing hardworking people of color to continue to be disproportionately victimized by the anti-social individuals in their communities is obviously no solution to crime and prison overcrowding. And simply dumping former inmates back into the  environments that created them in the first place tends to create a lot more crime rather than reducing it!

Are there too many people in prison? Yes! But that's because prisons now house hundreds of thousands of mentally disturbed individuals   who use to sequestered away in mental institutions for the criminally insane. But America shut down most of those institutions decades ago which is part of the reason why we also have so many homeless people on our streets today. 

America  also abandoned any type of serious rehabilitation in US prisons  decades ago. So we make it very difficult for former inmates to get jobs after they are out. What former inmate wants to tell a potential employer that he use to be in prison? And what employers wants to hire such an individual?

But simply feeling sorry for convicted felons and letting them out of prison early doesn't solve America's high crime problem.

The solution, in my opinion, is the rehabilitate convicted felons in prison and then put them in an environment where they are most likely to be productive citizens and not to return to crime. 

 So, the solution, in my opinion,  is:

1. Prison work programs where prisoners work for private and public institutions for half the state minimum wage with 60% of their income going back to the government  with the inmate only getting payed 40% of half the minimum wage as a salary. The money earned by the prisoner would be placed in a private bank account with the prisoner having absolutely no access to his or her funds-- until they are out of prison. This would allow former felons  to have substantial amounts of money in the bank once they are out of prison making it economically a lot easier for them to financially reintegrate back into society.

2. Private companies that employ former felons should get an annual payroll tax rebate from both the   Federal and State governments for every former felon that they employ.

3. Sentences for convicted felons should be a combination of prison time plus  temporary exile to designated Sanctuary Cities.

A Sanctuary City would be a walled working city within each US state or territory designated to accommodate domestic and foreign refugees (illegal aliens) and former prison inmates transition back into society. Such Sanctuary Cities would be declared by Congress as international territories under the jurisdiction of the Federal government. Anyone with a US passport or US visa would be allowed to visit, depart,  or even live and work within the walls of a Sanctuary City. Former felons would not be given passports to leave the Sanctuary City until they have completed their court mandated time within a Sanctuary City.

Felons who commit non-violent crimes should be given two years of exile within a Sanctuary City after they serve their prison sentences, IMO. Violent criminals would be exiled for five years within a Sanctuary City after serving their prison sentences.

Ex prisoners would also have full access to the money in their bank accounts once they are exiled to a Sanctuary City. This would allow states and the Federal government to shorten prison sentences while still not immediately dumping former prisoners right back into the environments that created their criminal activity in the first place.

Sanctuary cities would specialize in employing former prisoners with full workers rights and pay and would serve as test environments to see if a former prisoner has been truly rehabilitated. But rehabilitation through payed labor, providing tax incentives for employers to hire former felons, and serving the last few years of a felony sentence within the confines of designated Sanctuary Cities should dramatically lower the crime rate in most cities and towns in America, especially in minority neighborhoods, increasing public safety while catalyzing new economic growth and prosperity in America. 

I will elaborate a lot more on my Sanctuary City idea in future post since I believe that this concept would be the best way to  humanely deal with illegal immigration, domestic transients, and US prisoners transitioning back into society! 


References and Links


Number of murder victims by race in the US in 2020

Racism in Rape

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