Thursday, August 23, 2018

Utilizing the Phantom Express to Supply Water to Propellant Producing Orbital Depots

Artist rendition of a suborbital  Phantom Express with side mounted payload rocket (Credit: Boeing Aerospace)

During a recent 10 day testing period, Aerojet Rocketdyne  successfully hot-fired its new Space Shuttle Main Engine (SSME) derived  rocket engine-- the AR-22. The Sacramento, California headquartered company successfully demonstrated that the  AR-22 could be restarted every 24 hours for ten consecutive days. And this is a major step towards testing the new rocket engine's reusability  in  Boeing's future unmanned space plane-- the Phantom Express. 

Boeing's first test flights of the Phantom Express are currently scheduled for 2021. But the final test of the reusable space plane will entail launching the Phantom Express ten times in just  ten days while deploying payloads between  3000 to 5000 lbs (1.36 tonnes to 2.27 tonnes) to LEO with an expendable upper stage.

Launching the Phantom Express with a single rocket engine, the AR-22 will be designed to be utilized up to ten times before requiring refurbishment.  And each AR-22 engine will have an ultimate lifetime of 55 missions before before being completely replaced by a brand new AR-22 engine.  Boeing estimates the cost to launch a the Phantom Express to be less than $5 million. And Boeing plans to  commercialize the  Phantom Express, offering the space plane to both US government and commercial customers.

Artist rendition of Phantom Express at launch pad with side mounted cargo rocket (Credit: Boeing Aerospace)
Just seven AR-22 engines would have to be produced every year  in order for the Phantom Express to be  continuously launched on a daily basis.

If the  Phantom Express were used to transport a valuable commodity such as water to LEO then 13 to 22 tonnes of water could be launched into orbit in ten days for less than $50 million, more than 40 tonnes of water in a month, and  for less than $500 million. Optimally, the most advanced version of NASA's Space Launch System is eventually supposed to be able to deploy up to  130 tonnes of payload to orbit for about $500 million per launch. But for less than $500 million, 100 hundred launches of the Phantom Express could deliver between 130 tonnes to 220 tonnes of water to LEO.

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

Daily - 1.36  to 2.27 tonnes

Monthly - 40.8  to 68.1 tonnes

Yearly - 496.4  to 828.6 tonnes 

Water, of course, is an indispensable commodity for human survival on Earth. And water would be even more valuable for human commerce and survival in extraterrestrial environments. Aboard the ISS, water is used for drinking, washing, food preparation, and for the production of air through electrolysis. Water can also be used for growing fruits and vegetables, aquaculture, animal husbandry. Water can also be used for  shielding astronauts from the extremely deleterious heavy nuclei component of cosmic radiation while also mitigating the effects of cosmic radiation in general and ions from major solar events (solar storms).



But electrolysis used to produce oxygen for air also produces hydrogen. And electricity can also be used to liquefy both oxygen and hydrogen for use as a propellant for reusable extraterrestrial vehicles. While the current  SLS could deploy up to 90 tonnes to LEO, it can only transport about  25 tonnes of cargo on a trans lunar injection trajectory.  But with the assistance of LEO orbiting propellant producing water depots, a reusable extraterrestrial vehicle  such as the ULA's future LOX/LH2 fueled  Integrated Vehicle Fluids (IVF) ACES-68 could transport more than 50 tonnes of payload on a trans lunar trajectory. And a notional  IVF  modified SLS Exploration Upper Stage (R-EUS) could be used to  transport  more than 100 tonnes of payload on a trans lunar  trajectory.
Notional propellant producing water depot with twin solar array (Credit: Lockheed Martin)

The propellant producing water depots could be simply derived from the propellant tanks of extraterrestrial vehicles with the edition of radiation panels, water storage, electrolysis plants for splitting the water into hydrogen and oxygen , and cryocoolers to liquefy the gaseous hydrogen and oxygen. Such depots could also be equipped with IVF thrusters for station keeping and with rocket engines to enable the depot to self deploy practically anywhere within cis-lunar space and even into orbit around Mars, Venus, Jupiter, and the asteroids in the asteroid belt.

A depot derived from the ACES upper stage could store up to 68 tonnes of LOX/LH2 propellant while an EUS derived depot could store up to 128 tonnes of LOX/LH2 propellant. Reusable upper stage rockets that  use liquid methane instead of hydrogen as fuel, could utilize the excess amount of oxygen (22%) produced at depots that can't be used by the limited amount of  hydrogen produced.

The large solar arrays needed to provide power for propellant producing water depots in orbit could be deployed by commercial launch vehicles. The ULA's future Vulcan spacecraft with its 5.4 meter in diameter payload fairing could deploy a 300 MWe solar array to LEO with a single launch. Two such solar arrays docked to each other could provide up to 600 MWe of power within cis-lunar space.  Orbiting at  LEO, such depots should have access to ample sunlight for producing propellant 61% of the time. But at the Earth-Moon Langrange points, such as NRO, solar energy would be uninterrupted, allowing water depots to  produce liquid hydrogen and oxygen continuously as long as water is provided.

Reusable ACES or R-EUS derived orbital transfer vehicles could  transport water from LEO to other propellant producing water depots located at the Earth-Moon Lagrange points. But once water is manufactured and exported from the Moon's low gravity well, exports of water from LEO to the rest of cis-lunar space would probably be commercially non competitive. In fact, lunar sources of water might someday compete with water resources being exported to LEO from the surface of the Earth via the Phantom Express. 

Notional crewed Orion-ACES reusable shuttle approaching EUS derived propellant producing water depot @ NRO with 600 KWe solar array. The notional WPD-OTV-125 would be capable of storing up to 200 tonnes of water and up to  125 tonnes of LOX/LH2 water derived propellant. 
Traveling to the moon using a propellant producing water depot architecture could be much easier and safer since vehicles returning from deep space would simply return to Earth orbit instead of plunging directly through the Earth's atmosphere to the Earth's surface. Commercial Crew launched vehicles could simply launch astronauts or paying tourist to LEO to dock with a commercial space station. A reusable ACES upper stage perhaps joined with an Orion capsule with no Service Module would refuel at a nearby propellant depot and then dock with the space station to pick up the passengers from Earth. The Orion-ACES would then travel for about five days to an orbiting commercial outpost located at NRO (Near Rectilinear Lunar Orbit). A XEUS vehicle would refuel at a nearby propellant depot and then dock at the deep space habitat to pick up the passengers. Less than  12 hours would be required to transport the passengers to the lunar surface and the XEUS would still have enough propellant to return the crew back to the NRO habitat for the return trip to LEO and then back to the Earth's surface.

The daily deployment of water to LEO by the Phantom Express could allow other launch vehicles to focus their efforts on deploying passengers and large and heavy habitats, crewed interplanetary spacecraft, and other large structures to LEO where they could easily be transported to other areas of cis-lunar space and beyond by reusable orbital transfer vehicles such as the future ACES or IVF modified EUS. 

Links and References

SSME returns as AR-22 for rapid reuse demonstration, fired ten times in ten days

Engineers Test Fire Reusable Rocket

First Phantom Express spaceplane engine completed

Cis-Lunar Gateways and the Advantages of Near Rectilinear Orbits

Efficient Utilization of the Space Launch System in the Age of Propellant Depots



Monday, August 6, 2018

Thor and the Thorium Solution for Plutonium from Commercial Nuclear Reactors


"Thor's battle with the giants" painting by Mårten Eskil Winge (1872)
by Marcel F. Williams

Because of the political inability to deal with the long term disposal of spent fuel from commercial nuclear reactors in the US by the federal government, some states in the US have banned the building of new  commercial nuclear power plants.

California state law, for instance, has banned the construction of new commercial nuclear power plants until the US Federal government establishes a long-term policy on the disposal of spent fuel (nuclear waste). And with current plans to close its last nuclear power plant (Diablo Canyon) by the year 2025, California will eventually have no  nuclear facilities providing carbon neutral electricity to its nearly 40 million residents.

While the US has principally focused on finding a permanent site for the spent fuel from its commercial nuclear facilities, some nations, such as France,  have focused on recycling the plutonium component of spent fuel while storing away the fissile and fertile uranium for perhaps future use in commercial nuclear reactors-- plus the residual radioactive material that cannot be recycled

While France mixes plutonium with uranium 238 (MOX) to partially recycle nuclear waste in its current light water reactors, this process produces even more plutonium. But  a Swedish company (Thor Energy) has come up with an alternative solution. They propose mixing the plutonium from spent fuel with fertile thorium instead of fertile uranium 238. The utilization of such fuel in conventional light water reactors would allow for the plutonium to be incinerated while producing electricity while producing fissile uranium 233 that could be eventually extracted and used to enrich the spent fuel containing fissile uranium 235 and fertile uranium 238 stored away. This would allow most spent fuel produced from nuclear reactors to be recycled to produce even more carbon neutral energy.
North American Thorium Deposits

  
Countries with the Largest Thorium Reserves (tonnes)

India ......................    846,000
Turkey...................     744,000
Brazil ....................     606,000
Australia ...............    521,000
USA ......................     434,000
Egypt....................      380,000
Norway.................      320,000
Venezuela.............      300,000
Canada.................      172,000
Russia..................       155,000
South Africa........      148,000
China...................      100,000
Greenland..............     86,000
Finland..................      60,000
Sweden..................      50,000
Kazakhstan............     50,000


Thor Energy envisions using a mix of 90% thorium and 10% plutonium in conventional light water reactors.  Thorium Mox could also be used in future underwater light water nuclear reactors such as France's FlexBlue system.  Remotely sited underwater reactors could be used to produce carbon neutral synfuels (methanol, gasoline, jet fuel, diesel fuel, etc.) which could be shipped to coastal towns and cities around the world for  transportation and local heat and electricity production. 

But a Swedish company, Thor Energy,  has come up with a solution that utilizes  fertile thorium enriched with fissile plutonium, creating energy while incinerating plutonium and producing fissile uranium 233.

Links and References

Thor Energy

California's last nuclear power plant to close by 2025

Spent Fuel and the Thorium Solution 

Blue submarine: The Flexblue offshore nuclear reactor

 The Case for Remotely Sited Underwater Nuclear Reactors

Siting Ocean Nuclear Power Plants in Remote US Territorial Waters for the Carbon Neutral Production of Synfuels and Industrial Chemicals

Will Russia and China Dominate Ocean Nuclear Technology?

The Future of Ocean Nuclear Synfuel Production

Floating Nuclear Power Plants, Floating Power Barges, and Marine Methanol

Nuclear Navy's Synfuel from Seawater Program: An interview with Kathy Lewis of the U.S. Naval Research Laboratory


Monday, July 30, 2018

Simplified Extraterrestrial Cargo and Crew Landing Vehicles for the SLS


Notional crewed ELV-3 on the surface of the Moon
by Marcel F. Williams

During NASA's Constellation program, the American space agency chose Boeing's Altair concept as the landing vehicle design to  return American astronauts to the surface of the Moon. As a two staged (descent and ascent) crew landing vehicle and as a single stage cargo landing vehicle,  the Altair was supposed to be housed in the large payload fairing of the Ares V super heavy lift rocket. But in 2010, the Constellation program was  canceled by the Obama administration, a decision that became law in April of 2011. And this ended the development of  Ares V and Altair lunar landing vehicle. 
Notional Altair crew landing vehicle (Credit: NASA)
Notional Altair cargo landing vehicle (Credit: NASA)

A year later, Congress began funding a new heavy lift program, the Space Launch System (SLS),   while continuing to fund the development of the  Orion component of the Constellation program. While there has been no significant Congressional funding for a lunar landing vehicle, a large variety of a vehicle concepts have been proposed to return American astronauts and cargo back to the lunar surface by several space companies.  
2.4 meter super lightweight cryotank (Credit: Boeing Aerospace)
Here, I propose another  reusable extraterrestrial cargo and crew landing vehicle (the ELV-3) concept that would be much simpler than Boeing's Altair vehicle. The ELV-3 would be launched by the SLS and utilized  to  deploy very large and heavy cargo or crews to the lunar surface. And with the addition of a HIAD or an ADEPT deceleration shield, the ELV-3 could also deploy largo cargoes and crew to the surface of Mars.
Notional ELV-3 lunar lander display retractable panel
X-ray view of three tank configuration for ELV-3
View of ELV-3 radiator and side thrusters
Top x-ray view of ELV-3 and its three tank configuration
Technologically, the notional ELV-3 spacecraft proposed here would be a substantially simpler vehicle than Boeing's canceled Altair spacecraft. Instead of the Altair's descent vehicle's four liquid oxygen tanks accompanied by four liquid hydrogen tanks, the ELV-3 would have just two 2.4 meter in diameter hydrogen tanks plus one 2.4 meter in diameter liquid oxygen tank, all linear aligned within an octagonal shaped cruciform.

 The problems associated with eight feedlines, differential tank pull due to unuasable propellant, increased tank heating resulting from the numerous tank penetrations, problems with pressure control during burns and long coastal phases caused by the large number of tanks are significantly reduced by reducing the cryotank numbers from eight down to just three. Utilizing just three tanks also reduces the overall mass of the tank weight.

Problems associated with the RL-10 exhaust plume just a few meters above the lunar surface during landings could be alleviated by using side thrusters positioned well above the surface. Additionally, the IVF (Integrated Vehicle Fluids) ullage gas fueled thrusters could also be automatically extended outwards away from the side panels (more than 8.4 meters in diameter) for exceptionally large payloads that extend beyond the diameter of the octagonal panels.

While the deck of the  ELV-3 would be approximately two meters higher than the Altair, the ELV-3 would have the advantage of a substantial amount of empty space on each side of the linear aligned propellant tanks. Twin retractable wall panels on each side could  accommodate a rectangular cargo area at least 7.2 meters high by 2.2 meters by 2.8 meters.

ELV-3 - Cargo Lander

One 2.4 meter in diameter LOX tank

Two 2.4 meter in diameter LH2 tanks

IVF thrusters utilize ullage gasses 

Dry mass: 8 tonnes

Propellant mass: 31 tonnes

Maximum cargo mass to lunar surface from NRO (Near Rectilinear Orbit):  30 tonnes

Maximum cargo mass to lunar surface from LLO: 39 tonnes

Twin mobile lunar cranes stored within the ELV-3 side cargo areas with additional cargo located at the top central area

The large dimensions of the side cargo areas would also be able to accommodate twin mobile lunar cranes with telescopic booms extending well above the the top deck.  Each electric powered crane would be equipped with a cable hook for unloading large payloads and with cable clamshells for digging up and redepositing lunar regolith. With each mobile crane already weighing more than 12 tonnes, the deposition of lunar regolith (weighing approximately 1.5 tonnes per square meter) into the automatically expanded regolith bins of the other vehicle could increase each crane's counter weight by more than 18 tonnes. This would allow each mobile crane to be able to easily offload payloads on top of the ELV-3 weighing nearly 30 tonnes. If devices are deployed to the lunar surface to magnetically extract iron and other metallic dust  from the top ten centimeters of lunar regolith then the deposition of this much heavy material into the regolith bins could easily increase the counter weights of the mobile cranes by more than 100 tonnes.
Panel deployment of twin mobile lunar cranes  
The deployment of such mobile lunar cranes could, of course, be used to unload and transport payloads from a variety of other lunar landing cargo space craft.

Notional electric powered mobile lunar crane
The clamshell crane could also be used to deposit regolith within the surrounding walls of lunar habitats providing the large multilevel pressurized habitats with appropriate shielding against cosmic radiation (completely shielding the habitats from the heavy nuclei component). Such regolith shielding could provide the habitat with protection from micrometeorites and from the extreme thermal fluctuations from the lunar environment.

Mobile lunar crane using its telescopic boom to lift a 20 tonne SLS propellant tank derived lunar habitat from the top of an ELV-3 cargo lander. The 20 tonne payload, of course, would weigh only one sixth as much on the lunar surface.
The cargo version of the ELV-3 could also be utilized to transport large and heavy payloads to the martian surface if HIAD or ADEPT deceleration shields are utilized along with mobile cranes with lifting capabilities not too dissimilar to vehicles deployed to the lunar surface. 


ELV-3 - Crew lander

Dry mass with mass with passengers, cargo,  and radiation shielding: 16 tonnes

Maximum additional cargo to and from the lunar surface if able to refuel on the lunar surface: 14 tonnes

Notional ELV-3 crew landing vehicle
As a crew vehicle, the ELV-3 would use three pressurized modules derived from Boeing's 2.4 meter in diameter tank technology. The centrally positioned module (passenger module) would be the heaviest since it would be internally heavily shielded to protect astronauts from the exceptionally deleterious heavy nuclei component of cosmic rays. This would add at least four tonnes of extra shielding weight to the passenger module relative to the similar sized command module and airlock on opposite sides of the passenger module. The passenger module  would also serve as a storm shelter in case of a major solar event when the ELV-3 is moving through cis-lunar space.

Because of its weight and limited fuel (up to 31 tonnes of LOX/LH2 propellant), two  vehicles would be required for round trip sortie missions between NRO and the lunar surface. One ELV-3 would be used to transport the other ELV-3 and its crew to low lunar orbit while the crewed ELV-3 would land on the lunar surface and then return to lunar orbit after its mission where the orbiting ELV-3 would transport both vehicles  back to NRO.  So spacecraft such as the ULA's XEUS (up to 68 tonnes of LOX/LH2 propellant) and Lockheed Martin's MADV (80 tonnes of LOX/LH2 propellant) would be much more capable than the ELV-3 as a crew launch vehicle for sortie missions since  only one vehicle is required for sortie missions originating from NRO.

However,  once propellant producing depots are deployed to the lunar surface, only one ELV-3 vehicle would be required to transport crews between the Earth-Moon Lagrange points and the lunar surface and back. Additionally, the crewed versions of the ELV-3 would have a major advantage by being able to transport both astronauts plus more than 14 tonnes of additional payload to and from the lunar surface  when fully fueled.
After a side panel is deployed, astronauts ride an electric powered scissor lift down towards the lunar surface
If propellant producing water depots are deployed at LEO and NRO, the ELV-3 could also be used transport crews between LEO and NRO. This would provide NASA and private commercial space transportation companies with an alternate means from LEO to the Lagrange points.  

Utilizing its side cargo areas,  an unmanned ELV-3 could also be used  to deploy a multitude of mobile robots to the surfaces the Moon, the moons of Mars (Deimos and Phobos), to the moons of Jupiter (Io, Ganymede, Europa, and Callisto), and even to the surfaces of some of the the largest asteroids in the asteroid belt (Ceres, Vesta, Pallas, etc.). 


Links and References

Robust Lunar Exploration Using an Efficient Lunar Lander Derived from Existing Upper Stages
 
Altair spacecraft

Tanks for a Great Idea

Game Changing Propellant Tank

2.4 meter composite cryogenic tank at Boeing Developmental Center

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

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




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