Thursday, March 19, 2015

Establishing a Permanent Human Presence on Mars with a Lunar Architecture

ETLV-2 coupled with an ADEPT deceleration shield on its way the martian  surface
by Marcel F. Williams

"As we reported in August 2013, even after the SLS and Orion are fully developed and ready to transport crew NASA will continue to face significant challenges concerning the long-term sustainability of its human exploration program. For example, unless NASA begins a program to develop landers and surface systems its astronauts will be limited to orbital missions of Mars. Given the time and money necessary to develop these systems, it is unlikely that NASA would be able to conduct any manned surface exploration missions until the late 2030s at the earliest."

NASA Office of Inspector General
February 25, 2015


It is generally agreed by both the Congress and the Executive Branch  that sending humans to the surface of Mars, sometime in the 2030s, should be the long term goal of the National Aeronautics and Space Administration (NASA).  However, the intermediate destination during the 2020s needed to develop and to mature such space faring capability has been subject to controversy. While some have advocated a return to the lunar surface as a bridge towards Mars, others have argued that the  development of a lunar architecture could actually siphon off  necessary funds for sending humans to the martian surface.

The extraterrestrial deployment of  huge amounts of water will be essential for any interplanetary journey.  Even if some future Mars vessels are  xenon fueled solar electric interplanetary vehicles, crewed missions between cis-lunar space and Mars orbit will still require a substantial tonnage water for drinking, washing, food preparation, the production of air and for mass shielding habitat modules  from the dangers of  cosmic radiation and major solar events. The most expensive source of water for an interplanetary vehicle within cis-lunar space is from the Earth's deep gravity well.  However, water derived from ice in the Moon's polar regions would be a substantially cheaper source since the  Moon has a significantly lower gravity well.  Water, of course,  could also be used for the production of LOX/LH2 propellant necessary for  voyages between cis-lunar space and Mars orbit. 

ADEPT payload deployment scenarios for Mars (Credit: NASA)

Because of its thin atmosphere and higher gravity, Mars is a very different world than the Moon. Still,  habitat modules, propellant producing water depots,  and mobile ground vehicles that could be  utilized on the surface of the Moon could also be used on the surface of Mars.  This could save NASA enormous amounts of money since basically the same surface architecture for the Moon could also be deployed on the surface of Mars. So no new surface infrastructure unique to Mars would not have to be developed.

Vehicles designed to deploy cargoes and crews to the lunar surface could also be used to deploy cargoes and crews to the surface of Mars. But in order to safely deploy cargoes and crews to the martian surface, such  vehicles will need to be  shielded and decelerated through the thin martian atmosphere through the ADEPT or HIAD technologies currently being developed by NASA.

HIAD  decelerator entering martian atmosphere with crew vehicle (credit: Boeing)
HIAD and ADEPT technologies simply use a large expandable heat shield  to protect a spacecraft from the frictional heating of the thin martian atmosphere (100 thinner than the Earth's atmosphere) while also decelerating the vehicle enough to eventually allow the vehicle to utilize retrorockets to hover and land on the martian surface. The weight of these decelerating heat shields approach 50% of the payload being deployed to the surface. But NASA believes that these technologies should   enable them to deploy as much as 40 tonnes of payload to the martian surface. 
C-ETLV-5 cargo lander and ETLV-2 crew lander for deploying cargoes and crew to the surface of the Moon, Mars, and on the surfaces of the moons of Mars
In July of 1962, NASA invited private companies to submit proposals for the development of a Lunar  Module (LM). Seven years later, this lunar landing craft  took Neil Armstrong and Buzz Aldrin  to the surface of the Moon. Assuming a similar length of time for the development of a new  Extraterrestrial Landing Vehicle (ETLV), proposals submitted for an ETLV  in 2016 could result in the return of humans to the lunar surface by 2023. Thus, by the 2030's, the ETLV will be a mature landing vehicle ready to deploy humans and cargo to the surface of Mars.

If we assume that NASA's annual human spaceflight related budget remains at approximately $8 billion a year  over the next 25 years, then NASA will spend approximately $200 billion over the next quarter of a century on human spaceflight related technology, operations, and activities. $8 billion a year should be enough for NASA to establish a permanent human presence on the surface of the Moon in the 2020s and on the surface of Mars in the 2030s-- if such efforts are prioritized-- especially if NASA is no longer burdened with the $3 billion a year ISS program during the next two decades. 

Ares vehicle (ETLV-2 and ADEPT deceleration shield) for landing on Mars: A. ETLV-2 begins to dock with DS (deceleration shield); B. ETLV-2 trajectory burn propels the Ares towards Mars; C. ETLV-2 undocks with the DS, turning around 180 degrees; D. ETLV-2 docks with DS in a Mars entry configuration; E.  Ares vehicle enters the Martian atmosphere; F.  ETLV-2 separates from the DS after subsonic deceleration velocity is achieved; G. ETLV-2 decelerates further towards the martian surface before hovering and landing its crew.
A reusable single staged LOX/LH2  ETLV capable of a round trips between the Earth-Moon Lagrange points and the lunar surface should also be capable of easily transporting crews from the surface of Mars to Low Mars Orbit-- or even all the way to the surface of Mars's inner moon, Phobos. HIAD or ADEPT deceleration shield would, again, be used to deploy the crewed ETLV safely to the martian surface. The cost of developing a crewed  lunar landing vehicle  has been estimated to be as much as $8 to $12 billion. So over the course of seven years, the cost for developing an ETLV could range from $1.1 billion to $1.7 billion per year. And that's a cost that is certainly affordable with an $8 billion a year human spaceflight related budget.

ETLV-2 at a sintered landing area being refueled with LOX and LH2 for its departure to Mars orbit. 
Regolith shielded lunar habitats cheaply derived from SLS propellant tank technology could also be deployed to the martian surface using a lunar cargo lander and a, of course, a HIAD or ADEPT deceleration shield. Regolith shielding a martian habitat to a similar degree as a lunar habitat will be necessary since the level of cosmic ray exposure on the martian surface is not substantially lower than on the lunar surface.
Three habitat modules previously deployed by a C-ETLV-5. The pressurized habitats are shielded with 2 meters of martian regolith contained within the automatically deployed regolith wall. Solar charged batteries are used to provide power for the habitat at night. But nearby nuclear power units buried beneath the regolith will also provide supplementary power for the outpost.

Ionizing Radiation on the Surface of the Moon:

38 Rem - annual amount  of cosmic radiation on the Lunar surface during the solar minimum

11 Rem - annual amount of cosmic radiation on the Lunar surface during the solar maximum

Ionizing Radiation on the Surface of Mars:

33 Rem - annual rate of cosmic radiation on the surface of Mars beneath 16 gm/cm3 of Martian atmosphere during the solar minimum

8 Rem - annual rate of cosmic radiation on the surface of Mars beneath 16 gm/cm3 of Martian atmosphere during the solar maximum

Percentage of water contained in different regions on the martian surface.
Lunar water collecting mobile vehicles using microwaves used to extract water from the regolith at the lunar poles could also  be used on much of the martian surface. The water content of the lunar regolith at the lunar poles has been estimated to be approximately 5%. The water content of the martian regolith at the lower latitudes ranges from approximately 1 to 7% depending on the region. But there are large regions near the martian equator that may have regolith with a water content as high as 7%. At higher latitudes, the water content may be as high as 30%. And at the martian poles, the water content could be as much as 70%. 

Mobile water tanker and  microwave water extraction robot on Mars.

Solar powered WPD-LV-5 water storage and propellant producing unit on the surface of Mars. Additional power can be provided by nearby nuclear power units buried beneath the martian regolith. 

Small nuclear power units will probably be necessary to supplement the solar electric power supply at a martian outpost. While batteries and electric flywheels charged during the daytime could provide power for an outpost a night, dust storms could substantially reduce solar electricity for up to a month with dust particles blanketing the solar panels.  But small nuclear power units could run 24 hours a day for several years before having to be replaced. So during dust storms, it might be wise for the outpost  to contract the solar panels while mostly relying on nuclear power until the storm is over. Such nuclear power units for Mars should also probably be  initially tested on the lunar surface in the 2020s for a few years before they are eventually deployed at a martian outpost in the 2030s.

Nuclear power unit on the Moon with its reactor buried beneath the regolith and its cooling panels above the surface. Such units could also be utilized on the martian surface (Credit: NASA).

The Lunar Module

Future Mars Explorers Face Dusty Challenges

Tuesday, February 24, 2015

The Voyage of Charles Darwin

Fundamentally, science is about discovering the underlying simplicity behind the mystery and complexity of phenomena. And Charles Darwin did just that when he discovered that the diversity of plant and animal species on Earth and the morphological change in plant and animal species found in the fossil record was predominantly due to biological evolution through natural selection.

 The Voyage of Charles Darwin was a BBC biographical miniseries that was originally hosted by astronaut Neil Armstrong when it was first broadcast in the US on PBS.  Its a magnificent reflective journey by Charles Darwin aboard the HMS Beagle, a journey, of course, which later helped Darwin to develop his theory of 'Evolution through Natural Selection'.

The Voyage of Charles Darwin (Episode 1):

The Voyage of Charles Darwin (Episode 2):

The Voyage of Charles Darwin (Episode 3):

The Voyage of Charles Darwin (Episode 4):

The Voyage of Charles Darwin (Episode 5):


The Voyage of Charles Darwin (Episode 6 & 7):

Links and References:

Charles Darwin Wikipedia

The Second Voyage of the Beagle

Sunday, February 8, 2015

DARPA's Jet Fighter Satellite Launch Concept


Artist concept of Jet Fighter carrying a rocket capable of placing a 100lb satellite into orbit. (Credit: DARPA)

References and Links

Airborne Launch Assist Space Access (ALASA)

ALASA Wikipedia

Tuesday, January 27, 2015

Utilizing Lunar Water Resources for Human Voyages to Mars

At EML4, an OTV-400 interplanetary booster  undocks with a fuel depot (WPD-OTV-400) before proceeding to dock with the  Odyssey interplanetary spacecraft. 

by Marcel F. Williams

Long interplanetary journeys to  Mars, or to the orbit of Venus, or even to some of  the NEO asteroids could take several months or even years before their human occupants finally return to the relative safety of the Earth's surface. Such interplanetary voyages will require a substantial tonnage of water  for drinking, washing, the preparation of food,  the manufacturing of oxygen for air,  the production of  liquid oxygen and hydrogen for propellant, and for appropriately shielding humans inside of  habitat modules from the dangers of cosmic radiation and major solar events.

NASA delta-v estimates for  achieving Mars Transfer Orbits from LEO during the 2030s range above 3.8 km/s to just below 5 km/s-- just to reach the vicinity of Mars. Additionally,  a LEO departure for Mars would require launching the huge amounts of water and propellant for the voyage out of the Earth's enormous gravity well. This would require a delta-v ranging from 9.3 to 10 km/s.

However, if  crewed interplanetary vehicles are launched from an Earth-Moon Lagrange point, the delta-v requirements to achieve a Mars Transfer Orbit would be substantially lower. The delta-v requirements for departing cis-lunar space from one of the Earth-Moon Lagrange points could be less than 2 km/s-- especially if an Earth flyby or an Earth and Moon flyby (even better) are taken advantage of during the initial trajectory burns.

Providing water and propellant for  crewed interplanetary mission from the lunar surface to an Earth-Moon Lagrange point would also have a substantially lower delta-v requirement.  A  delta-v of less than  2.6 km/s would only be required to supply water and propellant to an interplanetary gateway at an  Earth-Moon Lagrange point. Contrast that with the  enormous  9.3  to 10 km/s delta-v that is need to  supply propellant and water to an interplanetary vehicle located at LEO.  The lunar supply of water and propellant to an interplanetary spacecraft at an  Earth-Moon Lagrange point would also have the additional economic advantage of being able to use single stage reusable vehicles. 

Earth-Moon Lagrange Points, the optimal gateways to interplanetary space within cis-lunar space.
So  launching  crewed interplanetary space craft to Mars from one of the Earth-Moon Lagrange points (L1, L2, L4, or L5) has a substantial delta-v advantage over launching crewed interplanetary spacecraft from LEO--  if such spacecraft are supplied with fuel and water from the surface of the Moon. 

During the 2030s, entering High Mars Orbit during a Conjunction Class Mission (330 to 560 day stays) would require an additional delta-v of 0.9 to 1.9 km/s, while entering High Mars Orbit during  Opposition Class Missions (60 day stay)  would require an additional delta-v trajectory burn ranging from  0.9 to 3.8 km/s. The additional delta-v requirements for reaching High Mars Orbit adds further support for minimizing the initial delta-v requirements when departing from cis-lunar space. So, again, supply fuel and water from the Moon from an Earth-Moon Lagrange point gateway would appear to be the optimal way to begin crewed interplanetary journeys. 

But how much water is there on the lunar surface? And how technologically difficult would it be  to extract large quantities of water from the lunar regolith?

A spectral analysis of the ejecta plume from the impact of  a Centaur upper stage  into the  Cabeus crater at the lunar south pole was conducted in 2009.  The analysis indicated that the lunar regolith in the shadowed crater contained water ice with concentrations ranging from 2.7% to 8.5% by mass. This suggest that  in some of the permanently shadowed craters at the southern pole, the lunar regolith there may contain as much as  27 to 85 kilograms of ice per tonne

The dark purple and blue areas represent neutron emissions from the Moon's polar regions that indicate  hydrogen-rich regions on the lunar surface covered by desiccated regolith (Credit: NASA) .  
In the Moon's northern polar region, the Mini-RF on board the Chandrayaan-1 orbiting probe strongly suggest that 40  craters in the northern polar region my contain as much as 600 million tonnes of water-ice. So there is clearly no shortage of  water resources on the lunar surface.

In order to provide enough water for human activities at a lunar outpost, a cis-lunar transportation system, and to supply propellant and mass shielding for five Conjunction or Opposition Class missions to Mars during the 2030s: 2030, 2033, 2035, 2037, and 2039, at least 500 to 1000 tonnes of water is going to have to be annually manufactured on the lunar surface.

A lunar water and fuel manufacturing depot along side of mobile LOX and LH2 storage tanks and a mobile microwave water extraction robot (Water Bug).

NASA researchers have demonstrated that a simple one kilowatt microwave oven could extract as much as a tonne of water from the regolith at the lunar poles over a one year period. A single mobile robot with a 100 kw powered microwave oven, therefore, should be  able to annually extract 100 tonnes of water from the regolith from the shadowed areas at the lunar poles. Ten such mobile microwave units might be able to extract 1000 tonnes of water per year from lunar polar regolith resources.

Solar extraction of water from lunar regolith brought from permanently shaded lunar craters at the lunar poles. Transparent domes allows sunlight to heat a layer of lunar regolith from the top while solar heated metal tubes below filled with methanol heat the regolith from below. Water vapor is deposited within regolith insulated cold trap canisters.

However, a simpler method may only require sunlight to passively extract water from the lunar regolith. If one tone of regolith from the shadowed areas of the  lunar poles is composed of  approximately 5% water ice then mobile lunar excavators capable of digging up and depositing at least one tonne of regolith into a solar heater could produce at least 50 kg of water per day (18 tonnes of water per year). Just a few electric powered or fuel cell powered excavation robots on the lunar surface could, in theory,  deposit at least one ton of icy regolith to a solar heater per hour (more than 400 tonnes of water per year).
A reusable water tanker shuttle on a microwave sintered launch pad after being loaded with lunar water and lunar fuel for its flight to a water and propellant depot at one of the Earth-Moon Lagrange points.

The Odyssey interplanetary vehicles would be crewed spacecraft capable of transporting 12 astronauts to High Mars Orbit and back to cis-lunar space using solar photovoltaic powered propellant producing water depots supplied with water from the lunar surface. The Orbital Transfer Vehicle (OTV-400) and the IAGH (Interplanetary Artificial Gravity Habitats) would both be derived from the SLS fuel tank technology.

 The OTV-400 would use  a common bulk-head LOX/LH2 fuel tank derived from the SLS fuel tank technology. An IVL(Integrated Vehicle Fluids) type of technology would be used to utilize ullage gases for attitude control. Space Works has proposed a similar type of OTV using IVL technology that would store more than 450 tonnes of LOX/LH2 fuel. However, the OTV-400 would also use photovoltaic powered cryocoolers to  virtually eliminate any hydrogen and oxygen boil-off.
The twin habitat modules of the IAGH would rotate to produce a 0.5g simulated gravity for the six humans inside each module. The IAGH would also  be  appropriately water shielded to protect  its most radiation vulnerable occupants (25 year old female astronauts) from excessive exposure to  cosmic radiation and its  heavy nuclei component in a addition to major solar events-- for up to four years-- during solar minimum conditions. 50 cm of water shielding would be required to appropriately shield the light weight twin SLS fuel tank derived living areas: 118 tonnes of water shielding for each habitat module, 236 tonnes of shielding in total. 
A reusable Orbital Transfer Vehicle (OTV-400) for transporting crewed artificial gravity habitats to the orbits of Mars, Venus, or to the NEO asteroids. While some of the ullage gases are utilized for attitude control, most of the ullage gases are reliquified by photovoltaic powered cryocoolers to prevent fuel loss, a technology already developed by NASA.

Conjunction Class Missions would only require one reusable OTV-400  storing close to 400 tonnes of LOX/LH2 propellant. The higher delta-v Opposition Class Missions will require two reusable OTV-400 boosters. Entering orbit around Mars and reentering cis-lunar space will also require the IAGH  to dump the water shielding from its habitat modules in order to substantially reduce the Odyssey's mass just before the final trajectory burns to enter Mars orbit or to enter cis-lunar space.

Coupled with a large water storage tank and a photovoltaic powered electrolysis plant  and cryocoolers, the OTV-400 would function as a water storage and hydrogen and oxygen producing propeelant depot (WPD-OTV-400). Still equipped with its own rocket engines, it could self deploy itself practically anywhere within the inner part of the solar system  while still being able to manufacture LOX and LH2 anywhere where there is a source of water.

The WPD-OTV-400 water and propellant depot would have the ability to transport itself to Mars orbit from the Earth-Moon Lagrange points after producing enough fuel for its on flight and filling up with enough stored water originating from the Moon. However,  once water is being manufactured on Deimos and Phobos, using the same technologies employed on the lunar surface, propellant from the lunar surface will no longer be required to replenish water and propellant supplies in orbit around Mars. 

Reusable Odyssey I interplanetary space craft with a crew of 12 at EML4 in a trajectory burn configuration for a Conjunction Class mission to High Mars Orbit  in the year 2033. 

After its initial trajectory burns on its way to Mars, the  OTV-400 boosters and the ETLV-2 vehicles (Extraterrestrial Landing Vehicles) would separate from the IAGH  and re-dock at its central axis.The Odyssey would, therefore, be reconfigured  to produce artificial gravity for its 12 person crew for their multi-month journey to Mars.   Liquid carbon dioxide rockets housed in each habitat module, would be used to rotate or to stop the rotation of the Odyssey. Cables will extend from the IAGH core more than 100 meters from the central axis of the vehicle. A series of light weight cylindrical metal or ceramic shells woulds also expand outwards creating rotational arms that would act as levers to increase, decrease, or stop the rotation of the Odyssey. 

Reusable Odyssey II interplanetary space craft with a crew of 12 at EML4 in a trajectory burn configuration for a 1000 day Opposition Class mission to High Mars Orbit (60 day stay) to explore the martian moons Deimos and Phobos while also deploying  satellite constellations at Sun-Mars L1 and Sun-Mars L2 to provide global communications for future human missions to the surface of Mars.
After several months of travel through interplanetary space,  the Odyssey would reconfigure itself again to prepare for an Orbital Insertion trajectory burn and the water shielding within IAGH modules would be dumped into space.  But after a day or two in Mars orbit, the Odyssey will once again reconfigure itself to produce artificial gravity for its crew. The  water shielding for the habitats could be fully  restored within a few hours or a few days from a pre-deployed  WPD-OTV-400 already in high Mars orbit. Returning to Earth will also require the Odyssey to be refueled by the orbiting water and propellant depot in Mars orbit.

Once in high Mars orbit, each fully fueled  crewed ETLV-2 vehicle would have enough fuel to travel to one of the Martian moons for a few days of exploration and sample retrieval  and back to the Odyssey. And if they wanted to travel to the martian moons a second time then they could refuel at the orbiting Mars depot (WPD-OTV-5).

A slowly rotating Odyssey II in an interplanetary configuration to provide a simulated gravity of  0.5 g  for six crew members in each of the  IAGH habitat modules. 
Since the Odyssey is intended for reuse (ten times with its RL-10 engines) for future interplanetary missions, a trajectory burn will be required to return to the Earth-Moon Lagrange points after the trajectory burn for Trans-Earth Injection from Mars orbit. Again, this will require the Odyssey to completely dump its water shielding before the burn. Once the crew is back within cis-lunar space, they will only be a few hours away from protective shelters on the lunar surface or just a few days away from the Earth's surface.

After the 12 person crew completes their 60 day mission in High Mars Orbit, the Odyssey II converts from it's artificial gravity configuration to a trajectory burn configuration for its Trans-Earth Injection burn to begin its journey back to cis-lunar space.

 Because the major Odyssey components are reusable, the recurring cost for the interplanetary vehicle should be substantially lower that other interplanetary vehicle concepts that utilized expendable interplanetary boosters. The Odyssey's RL-10 or RL-10-like rocket engines could also be periodically replaced after perhaps ten round trips between cis-lunar space and Mars orbit which could further reduce their recurring cost.

The human safety advantages of using  lunar water resources for an SLS derived reusable artificial gravity producing  interplanetary spacecraft   deployed at one of the Earth-Moon Lagrange points should also be substantial:

1. The significantly reduced delta-v requirements at an Earth-Moon Lagrange point for fueling and mass shielding a crewed interplanetary vehicle should alleviate any pressure to significantly reduce the appropriate mass shielding of habitat modules against the dangers of cosmic radiation and major solar events. 50 cm of water shielding should also eliminate the possibility of space career ending radiation exposure during a single interplanetary mission for the most vulnerable occupants to radiation.

2. The rotating interplanetary artificial gravity habitats (IAGH) could significantly or totally eliminate long periods of exposure to the  deleterious physical effects of a microgravity environment

3. Having twin AGH habitats allows astronauts the enhanced safety of being able to seek refuge in the opposite habitat in case there is a serious life safety malfunction at the other habitat.

4. The more comfortable accommodations of the spacious SLS derived artificial gravity habitats could significantly reduce the psychological stress experienced by the drew  during several months or years of interplanetary travel.

5. The dangers and the complexity of direct, high-energy aerobraking into the atmospheres of Mars or during a return to directly to Earth would be avoided by limiting the Odyssey's flight path to travel only between the Earth-Moon Lagrange points and High Mars Orbit.

6. With at least one partially fueled  ETLV-2 (Extraterrestrial Landing Vehicle) connected to the Odyssey, any major malfunction of the OTV-400 during an orbital capture trajectory could allow astronauts to safely enter Mars orbit or cis-lunar space via the ETLV-2 vehicle or vehicles.  Even though this would mean the loss of the Odyssey spacecraft, the crew could still safely enter Mars orbit or cis-lunar space via the ETLV-2. However, Entering Mars orbit aboard an ETLV-2, without the Odyssey IAGH would require that an appropriately mass shielded space station already be pre-deployed in Mars orbit.

References and Links

Considerations for Designing a Human Mission to the Martian Moons (NASA)

A Study of CPS Stages for Missions beyond LEO (Space Works)

Mission and Implementation of an Affordable Lunar Return (Spudis & Lavoie) 

 Using the resources of the Moon to create a permanent, cislunar space faring system (Spudis & Lavoie)

Evolving to a Depot-Based Space Transportation Architecture (ULA)

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

 Utilizing the SLS to Build a Cis-Lunar Highway

Cosmic Radiation and the New Frontier

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Destination Moon

glennwsmith said... Very nice, Marcel. This is one of the most beautifully put together, forward-looking, and yet also understated videos which I've yet seen from a major space agency -- and it just goes to show that there's a lot of good material out there if you know where to find it.

G. W. (Glenn) Smith


Stena Line to Covert Passenger Ferry to a Methanol Fueled Sea Vessel

michael jordan said...

Stena Germanica RoPax ferry is the first commercial marine vessel to run on Methanol.It is the largest ferry in the Nordic region and second biggest Ro-Pax ferry in the world.For this overall project cost comes to nearly $25.5m.It measures 240m long and 29m wide and lane metres of 3,907m.It is going to accommodate 300 cars and 1,300 passengers and freight capacity of 46,353t.