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| Notional crewed ELV-3 on the surface of the Moon |
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.
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| Notional Altair crew landing vehicle (Credit: NASA) |
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| Notional Altair cargo landing vehicle (Credit: NASA) |
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| 2.4 meter super lightweight cryotank (Credit: Boeing Aerospace) |
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| Notional ELV-3 lunar lander display retractable panel |
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| X-ray view of three tank configuration for ELV-3 |
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| View of ELV-3 radiator and side thrusters |
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| Top x-ray view of ELV-3 and its three tank configuration |
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
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| 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.
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| Panel deployment of twin mobile lunar cranes |
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| Notional electric powered mobile lunar crane |
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| 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. |
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
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| Notional ELV-3 crew landing vehicle |
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.
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| After a side panel is deployed, astronauts ride an electric powered scissor lift down towards the lunar surface |
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
Tanks for a Great Idea
Game Changing Propellant Tank
2.4 meter composite cryogenic tank at Boeing Developmental Center
Shielding to protect against "the exceptionally deleterious effects" of heavy nuclei is explained exceptionally well in a Scientific American article by Eugene Parker titled "Shielding Space Travelers". The minimum effective mass (for a small capsule) is around 400 tons. Less than this and secondary radiation from heavy nuclei hitting the shielding produces more radiation that what it stops. This is the elephant in the room nobody- not the space agency or NewSpace proponents- will admit exists. And why you keep going on about going to Mars is a mystery to me. Mars, like LEO, is a dead end Marcel.
ReplyDeleteThere's a big difference between short term exposure to radiation and long term exposure to radiation.
ReplyDeleteTemporary exposure (a few months) to cosmic radiation and its extremely deleterious heavy nuclei component (~1%) is not the same as long term exposure(several years).500 tonnes of water shielding or 400 tonnes of polyethylene shielding would only be required for habitats that are-- permanently-- occupied.
And-- permanent-- space stations deployed in cis-lunar space beyond the Earth's magnetosphere can be easily shielded with regolith exported from the lunar surface. Space stations in orbit around Mars can be shielded with regolith extracted from the surfaces of Deimos or Phobos.
Interplanetary vehicles-- traveling less than two years-- through interplanetary space, however, require much less shielding because of their-- temporary-- exposure to cosmic radiation. And such vessels only require 30 to 50 cm of water shielding to mitigate cosmic radiation to acceptable exposure levels while also protecting them against heavy nuclei and major solar events which would require only 30 to 50 cm of water shielding. And such water shields could be easily dumped before final trajectory burns into orbit around Mars and with their shields being replenished again by water depots already deployed in orbit.
"…heavy nuclei GCR particles are stopped by ~10 centimeters of regolith while all other GCR (GeV) particles are stopped by 1000g/cm3 of material which equates to 5 meters of lunar regolith (2g/cm3) or the Earth!s atmosphere."
Lindsey, 2003, International Lunar Conference
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"The heavy nuclei in the galactic cosmic rays are usually stopped by ionization energy losses within ~10 cm of the lunar surface. Most of the radiation damage induced by these heavy GCR nuclei occurs within the top few centimeters. This radiation damage is so intense that it can be seen as high densities of tracks in lunar samples (Walker, 1975; Reedy et al., 1983) and can cause problems in sensitive electronic components (Adams and Shapiro, 1985). Shielding of a few g/cm2 is usually adequate to remove most of these highly- ionizing heavy GCR nuclei."
LUNAR SOURCEBOOK A User’s Guide to the Moon
GRANT H. HEIKEN
Los Alamos National Laboratory
DAVID T. VANIMAN
Los Alamos National Laboratory
BEVAN M. FRENCH
National Aeronautics and Space Administration
No journey Beyond Earth and Lunar Orbit (BELO) is "for a few months" Marcel. As I stated, partial shielding actually increases exposure due to secondary radiation generated by the shielding itself. Eugene Parker, the recognized authority on planet Earth concerning space radiation, explained it quite clearly so anybody can understand (in his Scientific American article). You are cherry picking from sources that are not stating, or misstating, the actual hazards of deep space dosing from heavy nuclei. You need to stop going cheap like the rest of them are trying to do Marcel.
ReplyDeleteThe NASA limit for radiation exposure for a year is 50 Rem. Just 30 cm of water shielding during solar minimum conditions (the worse conditions)would only expose astronauts to less than 30 Rem per year. So an eight month journey to Mars during solar minimum conditions would only expose astronauts to about 20 Rem of radiation.
ReplyDeleteDuring solar maximum conditions, radiation levels are significantly lower but major solar events are much more likely to occur during solar maximum conditions. But 30 cm of water would still be enough to mitigate the effects of a major solar storm. So all you really need is about 30 cm of water to protect astronauts from excessive radiation during interplanetary journeys that last less than 20 months.
NASA's allowable-- lifetime-- exposure to radiation depends on age:
100 Rem - maximum career exposure limit to ionizing radiation for a 25 year old woman
150 Rem - maximum career exposure limit to ionizing radiation for a 25 year old man
175 Rem - maximum career exposure limit to ionizing radiation for a 35 year old woman
250 Rem -maximum career exposure limit to ionizing radiation for a 35 year old man
250 Rem -maximum career exposure limit to ionizing radiation for a 45 year old woman
325 Rem -maximum career exposure limit to ionizing radiation for a 45 year old man
300 Rem -maximum career exposure limit to ionizing radiation for a 55 year old woman
400 Rem -maximum career exposure limit to ionizing radiation for a 55 year old man
Like my comment said- you are misstating by conflating solar storms with heavy nuclei. Two completely different types of radiation. The damage deep space heavy nuclei causes to the nervous system and DNA is.....unknown. Because there is no data there is no problem according to NASA and NewSpace. It is a scam. Multi-year missions to the outer solar system will only happen with a near-sea-level-radiation-environment and 1G of artificial gravity (most likely using a tether system). There is only one system of propulsion that can push a massive-cosmic-ray-water-shield and tether system around the solar system fast enough to keep missions within psychological limits: Nuclear Pulse Propulsion (bombs). The only place to acquire the shielding, assemble,test,and launch such nuclear missions is the Moon. And water works great for pulse unit reaction mass. No fuel depots needed. LEO and Mars are absolutely not the places to go. These simple facts expose the NewSpace scam- which revolves around the flagship company products and P.R. appeals to emoting clueless sci-fi fans. The Parker Dyson Spudis Continuum, Gerard K. O'Neill's vision of space colonization, and a state sponsored program of Super Heavy Lift Vehicle launches is the path to expanding humankind into the solar system. Deviating from that path is simply promoting failure. Stop failing Marcel.
ReplyDeleteInterplanetary journeys are going to have to protect astronauts from cosmic radiation and major solar events. Fortunately, only 20 gm/cm2 of mass is needed to protect astronauts from the cell killing bombardment of the heavy nuclei component of cosmic radiation as I have already referenced by NASA and the Los Alamos Laboratory above.
ReplyDelete20 gm/cm2 is also enough to protect astronauts from major solar events. 30 gm/cm2 of radiation shielding, however, would be required to reduce radiation exposure well below NASA's 50 Rem per year requirement.
The Parker levels of radiation protection needed to mitigate ionized hydrogen and helium nuclei and the resulting neutrons produced from cosmic radiation bombardment will probably only be required for-- permanent-- habitats in space and on the surfaces of worlds such as the Moon, Mars, Mercury, and Callisto.