Around the Moon for Eighty Days: Remembering the Half-Century Anniversary of Lunar Orbiter-1

The grainy significance of this image, acquired by Lunar Orbiter-1 on 23 August 1966, is that it is the very first view of Earth, as seen from lunar distance. At the time, the spacecraft was on its 16th orbit around the Moon. Photo Credit: NASA

The grainy significance of this image, acquired by Lunar Orbiter-1 on 23 August 1966, is that it is the very first view of Earth, as seen from lunar distance. At the time, the spacecraft was on its 16th orbit around the Moon. Photo Credit: NASA

For countless millennia, the Moon has captivated the fascination of humanity, but only in the last few decades has our species had the technological ability and scientific knowledge to visit and explore our closest celestial neighbor. In May 1961, President John F. Kennedy committed the United States to landing a man on the lunar surface, and returning him safely to Earth, before the decade’s end. However, in order to do so, the systems necessary to deliver that man to the Moon had to be conceived and perfected. Moreover, the very nature of the Moon itself—from the consistency and load-bearing characteristics of its regolith to the appropriateness of its rugged terrain to support a heavy spacecraft and human explorers—was acutely unknown.

At the midpoint of the decade, between August 1966 and January 1968, five unmanned Lunar Orbiter missions were launched and operated by NASA, successfully mapping 99 percent of the surface at resolutions of better than 200 feet (60 meters). In doing so, they provided vital data which would enable the space agency to ultimately select a series of five potential landing zones for the first Apollo explorers. And the first of those five trailblazers, Lunar Orbiter-1, completed its 80-day mission by impacting the Moon on 29 October 1966, 50 years ago, tomorrow. Not only was it a huge success, but it also marked the first time that the United States had ever placed one of its own spacecraft into lunar orbit.

Although plans for an in-situ examination of the Moon had been under serious discussion since the late 1950s, it was not until the months after Kennedy’s decision that the seeds of the Lunar Orbiter program were sown. Originally, it was hoped that modifications could be made to another pair of spacecraft families—Ranger and Surveyor—to fulfill this requirement, but neither could meet the level of mapping precision necessary to select Apollo landing sites. Specifically, the orbiter would need to record objects in the region of 147.6 feet (45 meters) in diameter across the entire lunar surface, with enhanced resolution of 14.7 feet (4.5 meters) in the areas of primary interest and still better resolution down to just 4 feet (1.2 meters) at landing spots.

In December 1963, NASA Administrator Jim Webb announced the selection of Boeing to develop the Lunar Orbiter. The three-axis-stabilized spacecraft weighed about 848 pounds (385 kg) and assumed the form of a truncated cone, measuring 5 feet (1.5 meters) across its base and standing 5.6 feet (1.7 meters) tall. At its base, it boasted a quartet of power-producing solar arrays and high-gain and low-gain antennas. Lunar Orbiter’s lowermost segment housed the nickel-cadmium batteries, transponders, flight programmer, photographic system, Inertial Reference Unit (IRU), Canopus star-tracker, command decoder, multiplex encoder, and Traveling-Wave-Tube Amplifier (TWTA). The spacecraft’s middle “deck” accommodated the velocity control engine, with a thrust of 100 pounds (45.3 kg), together with propellant tanks, a coarse Sun-sensor, and micrometeoroid detectors. Finally, the uppermost deck carried four attitude control thrusters and a heat shield to guard against the exhaust from the velocity control engine.

Lunar Orbiter-1 roars away from Launch Complex (LC)-13 on 10 August 1966. Photo Credit: NASA

Lunar Orbiter-1 roars away from Launch Complex (LC)-13 on 10 August 1966. Photo Credit: NASA

However, the key role of Lunar Orbiter was to acquire imagery of the Moon’s surface. Eastman Kodak provided a scaled-down Air Force photographic system, featuring a twin-lens camera for simultaneous imagery at high and medium resolution. “On a single mission,” noted Bruce Byers in Destination Moon, the official NASA history of the Lunar Orbiter program, “the orbiter could photograph a greater area of the lunar surface and also obtain more detailed photographic data than any other proposed system. Moreover, if loss of the use of one lens occurred … the whole photographic mission would not be ruined.”

In essence, the photographic system could provide imagery of areas up to 3,000 square miles (8,000 square km) at high resolution, which was four times better than NASA had requested. Drawing its heritage from the military, it was miniaturized in size and weight to fit aboard its launch vehicle, an Atlas-Agena D booster. “Film from a supply reel passed through a focal plane optical imaging system and controlled exposures were made,” wrote Byers. “Once past the shutter, the film underwent a semi-dry chemical developing process and then entered a storage chamber. From here it could be extracted upon command from the ground for scanning by a flying-spot scanner and then passed on a take-up reel.” Eastman Kodak also incorporated its Bimat process, which eliminated the need to use “wet” chemicals on the film. “Instead,” Byers continued, “a film-like processing material was briefly laminated to the exposed film to develop and fix the negative image … Once the film had been developed and fixed, the Bimat material separated from the film and wound onto a storage spool.”

In spite of early concerns over experiment integration, delays in the fabrication of spacecraft adapter hardware for the Atlas-Agena D, problems with the Lunar Orbiter propellant tanks, and difficulties in the certification of Eastman Kodak’s imaging system, the program entered major development by mid-1965. Final testing was completed early the following year, although the launch date for Lunar Orbiter-1 slipped from early June 1966 into mid-July and eventually into the second week of August. These slips were caused in part by delays in the delivery of Eastman Kodak’s imaging system, coupled with demands imposed on the Deep Space Network (DSN) by the Surveyor-1 lunar lander, which had launched at the end of May. At length, on 25 July, a Flight Readiness Review (FRR) was concluded at Cape Kennedy in Florida and Lunar Orbiter-1 was confirmed as ready to launch, no sooner than 9 August.

At the beginning of the month, the imaging system was installed aboard the spacecraft and Lunar Orbiter-1 was transferred to Launch Complex (LC)-13 at the Cape for integration aboard the Atlas-Agena D. (Interestingly, LC-13 is today operated by SpaceX and has been reconfigured as Landing Zone-1 for its returning Upgraded Falcon 9 first-stages.) The countdown operations on the 9th proceeded normally until T-7 minutes, when an anomaly with the booster’s propellant utilization system forced a 24-hour scrub. The next day met with no such problems and Lunar Orbiter-1 roared aloft at 3:26 p.m. EDT. Within five minutes of leaving the Cape, the spacecraft was boosted into an initial “Earth-parking” orbit, after which the Agena was restarted to deliver Lunar Orbiter-1 onto a four-day voyage through cislunar space to reach the Moon.

Problems were experienced during the journey with the Canopus star-tracker; a particularly worrisome circumstance, in view of the fact that the spacecraft depended upon proper orientation along its yaw, pitch, and roll axes to reach the Moon’s vicinity in the correct attitude to achieve orbit. Work-around procedures were developed, whereby Lunar Orbiter-1 was commanded to establish a roll reference, pointing the Canopus sensor toward the Moon at the point of its mid-course correction maneuver. This proved successful and with the sensor locked onto the Moon, controllers were reasonably confident that it was functioning correctly. The spacecraft also suffered issues of overheating systems during its transit phase, but by the morning of 14 August it was less than 7 miles (10 km) off its planned orbit-insertion point. Commands to inject Lunar Orbiter-1 into a highly-elliptical path around the Moon got underway at 11:22 a.m. EDT.

Schematic of the Lunar Orbiter spacecraft, five of which flew to the Moon between August 1966 and January 1968. Image Credit: NASA

Schematic of the Lunar Orbiter spacecraft, five of which flew to the Moon between August 1966 and January 1968. Image Credit: NASA

Operating from an “apolune” of 1,160 miles (1,867 km) and a “perilune” of 117 miles (189 km), America’s first mission in lunar orbit was finally underway. For the next 2.5 months, Lunar Orbiter-1 was exclusively focused upon potential Apollo landing sites. Its first imaging location was part of Mare Smythii, on the easternmost edge of the lunar near side, and high-resolution photographs were acquired every 10 seconds. And despite problems with the imaging system itself, the spacecraft was “deboosted” to a lower altitude of 25 miles (40.5 km) for further photography. By month’s end, images of nine potential Apollo landing sites had been taken, as well as early surveys of the lunar far side. Additionally, Lunar Orbiter-1 returned the first image of Earth, as seen from the vicinity of the Moon.

An extended mission got underway in mid-September, but by the tail end of October it was apparent that the spacecraft was deteriorating. Its attitude control system was depleted of propellant, its overheating battery was rapidly losing power, its transponder was behaving erratically, and the IRU was struggling to maintain stabilization. All told, it was anticipated that the ability of the spacecraft to remain stable would last between two and five weeks. As a result, Lunar Orbiter-1 was deliberately crashed into the far side during its 577th orbit on 29 October 1966. As a result, 50 years ago today, America’s first mission to enter lunar orbit came to a conclusion, with 42 high-resolution and 187 medium-resolution images having been returned, covering 1.93 million square miles (5 million square km) of the Moon. All told, 75 percent of the planned mission objectives were fulfilled.

Lunar Orbiter-1’s pathfinding voyage gave way to four more missions over the course of the following 15 months. The next two spacecraft to be launched—Lunar Orbiter-2 in November 1966 and Lunar Orbiter-3 in February 1967—also focused upon 20 potential Apollo landing sites, whilst the last pair entered high-altitude polar orbits and followed broader scientific objectives. Specifically, Lunar Orbiter-4, which rose from Earth in May 1967, photographed the entire lunar near site, as well as 10 percent of the far side, whilst Lunar Orbiter-5, launched in August 1967, completed far-side coverage and achieved an imaging resolution as fine as 66 feet (20 meters). By the time the final Lunar Orbiter-5 was impacted into the Moon in January 1968, around 99 percent of the surface had been imaged. In a very significant sense, the program contributed enormously to our understanding of our closest celestial neighbor and built confidence as the United States prepared to send the first humans to the Moon.

 

 

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13 comments to Around the Moon for Eighty Days: Remembering the Half-Century Anniversary of Lunar Orbiter-1

  • Interesting to note that the early moon probes, both US and Soviet, took the “quick” 3-4 day route to the Moon unlike the current method of doing some sort of looping maneuvers around the Earth, etc. prior to arriving at the Moon (and other destinations).

  • James

    The title, “Around the Moon for Eighty Days: Remembering the Half-Century Anniversary of Lunar Orbiter-1” got me thinking about the pragmatic usefulness of the Moon and how polar Lunar water and other useful resources could be shipped to Low Lunar Orbit, or LLO, in a way that might be more efficient and much cheaper than a reusable Lunar Lander.

    Use a railgun at the Lunar surface ISRU base to shoot water filled projectiles into LLO and another railgun at the depot in LLO to shoot nearly empty projectiles back to the Lunar ISRU base.

    Or, if the projectiles containing resources are made of aluminum, keep them in LLO and turn them into lots of aluminum nano-particle rocket propellant.

    Or, if the projectiles are made out of steel, keep them in LLO and turn them into very effective Galactic Cosmic Radiation shielding. Iron is one of the best shielding materials we have against dangerous high energy Galactic Cosmic Radiation which is the most difficult to shield against type of risk adding radiation we face while in space.

    “The railgun projectile travels at 1.26 miles per second,”

    From: ‘The Zumwalt Destroyer Is Here, Now What About the Railgun?’
    By Kyle Mizokami
    Oct 19, 2016
    At: http://www.popularmechanics.com/military/navy-ships/a23440/zumwalt-destroyer-railgun/

    Note: Low Lunar Orbital velocity is about 1.6 kilometers per second.

    A railgun can shoot a projectile at 1.26 miles or over 2 kilometers per second.

    “The LLO Propellant Depot must be capable of electrolyzing the water in an efficient manner and storing it with essentially zero boil-­‐off (no losses) for a long period of
    time (1-­‐2% over several months timescale). This capability must be demonstrated as a
    prerequisite for determining overall viability of this concept.”

    From: ‘The Purpose of Human Spaceflight and a Lunar Architecture to Explore the Potential of Resource Utilization’
    By Tony Lavoie and Paul D. Spudis 2016
    At: http://www.spudislunarresources.com/Bibliography/p/119.pdf

    Of course the much easier to store alternative Lunar ISRU propellants of H2O2 and nano-particles of aluminum could also work in such a system.

    And if needed, H2O2 could also be used as an easy to store mono-propellant.

    • se jones

      “Iron is one of the best shielding materials we have against dangerous high energy Galactic Cosmic Radiation”

      No it’s not, what h*^# are you talking about?

      • James

        Lunar iron seems to be a better high energy Galactic Cosmic Ray shielding material than Lunar water for several reasons.

        “Our analysis concludes that the common belief that more material is better holds up well when considering low-Z hydrogenous materials for cosmic shields. The hydrogenous materials modeled for this study were polyethylene (PE), borated polyethylene (BPE), and water. The effectiveness of each of these materials in shielding cosmic neutrons, protons and muons was similarly poor.”

        “For a given thickness, iron outperforms lead by a factor of 5 and hydrogenous materials on average by a factor of 20, making it the shielding material of choice for neutrons above 20 MeV.”

        From: ‘Cosmic Ray Interactions in Shielding Materials PNNL-20693 Prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830’ By E Aguayo, RT Kouzes, AS Ankney, JL Orrell, TJ Berguson, and MD Troy July 2011
        At: http://www.pnnl.gov/main/publications/external/technical_reports/PNNL-20693.pdf

        • se jones

          Oh for cripes sakes. This paper is about shielding a high-purity germanium neutrino detector chip from it’s production in Zelonogorsk, Russia to installation 4800 feet underground in the Sanford Underground Laboratory at Homestake, South Dakota. The chip must be kept in calibration from its enrichment in Russia to installation in the ultra-high-purity copper cryostats, detector mounts, and inner shield. All this exquisite hardware is to search for Neutrinoless Double-beta Decay.

          If you bothered to read the paper (or understand it . . doubtful) you woulda been tipped off by all the talk with graphs about shielding from neutrons. Of course, a smart space guy like James would know that free neutrons only last for 10 to 15 minutes, so it’s not likely a neutron flux would be a problem in deep space. Look – the radiation in this paper is just secondary radiation at the earth’s
          surface produced from the cosmic ray flux together with the background radiation from the rocks in the mine and the exotic copper cryostats.
          Any stray particles will complicate the sensitive measurements of the experiment.

          lIQUID HYDROGEN is THE best material for shielding from the RELATIVISTIC IONS Astronauts will face. Polyethylene is good too as it has lots of hydrogen, but plastic can be shaped into useful s/c structure.

        • James

          The Earth’s atmosphere acts as a massive and effective Galactic Cosmic Ray shield that weighs over 14 pounds per square inch or about 1000 grams per square centimeter of air shielding mass. Effective Galactic Cosmic Ray shielding is not lightweight and what happens or doesn’t happen inside the shielding material is also important.

          “An air shower is an extensive (many kilometres wide) cascade of ionized particles and electromagnetic radiation produced in the atmosphere when a primary cosmic ray (i.e. one of extraterrestrial origin) enters the atmosphere. The term cascade means that the incident particle, which could be a proton, a nucleus, an electron, a photon, or (rarely) a positron, strikes an atom’s nucleus in the air so as to produce many energetic hadrons. The unstable hadrons decay in the air speedily into other particles and electromagnetic radiation, which are part of the shower components. The secondary radiation rains down, including x-rays, muons, protons, antiprotons, alpha particles, pions, electrons, positrons, and neutrons.”

          And, “The dose from cosmic radiation is largely from muons, neutrons, and electrons, with a dose rate that varies in different parts of the world and based largely on the geomagnetic field, altitude, and solar cycle. The cosmic-radiation dose rate on airplanes is so high that, according to the United Nations UNSCEAR 2000 Report (see links at bottom), airline flight crew workers receive more dose on average than any other worker, including those in nuclear power plants.”

          From: ‘Air shower (physics)’ Wikipedia
          At: https://en.wikipedia.org/wiki/Air_shower_%28physics%29

          Note from the above, “The dose from cosmic radiation is largely from muons, neutrons, and electrons,”. Stopping neutrons that are produced in the shielding material or avoiding the production of neutrons in the shielding material is useful for effective Galactic Cosmic Ray shielding.

          “The number of particles starts to increase rapidly as this shower or cascade of particles moves downwards in the atmosphere. On their way and in each interaction the particles loose energy, however, and eventually will not be able to create new particles. After some point, the shower maximum, more particles are stopped than created and the number of shower particles declines. Only a small fraction of the particles usually comes down to the ground. How many actually come down depends on the energy and type of the incident cosmic ray and the ground altitude (sea or mountain level). Actual numbers are subject to large fluctuations.”

          And, “In fact, from most cosmic rays nothing comes down at all. Because the earth is hit by so many cosmic rays, an area of the size of a hand is still hit by about one particle per second. These secondary cosmic rays constitute about one third of the natural radioactivity.”

          From: ‘Cosmic-ray air showers’ By Konrad Bernlöhr.
          At: https://www.mpi-hd.mpg.de/hfm/CosmicRay/Showers.html

          As quoted in my previous post from ‘Cosmic Ray Interactions in Shielding Materials PNNL-20693 Prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830’:

          “For a given thickness, iron outperforms lead by a factor of 5 and hydrogenous materials on average by a factor of 20, making it the shielding material of choice for neutrons above 20 MeV.”

          That’s not so hard to understand, is it?

          There is the real possibility that layers of other materials may also be used with iron, but I have yet to see any research to compare or demonstrate the utility of such combinations of iron and other shielding materials against dangerous high energy Galactic Cosmic Rays.

          • se jones

            “For a given thickness, iron outperforms lead by a factor of 5 and hydrogenous materials on average by a factor of 20, making it the shielding material of choice for neutrons above 20 MeV.”

            “That’s not so hard to understand, is it?”

            For you yes, evidently it is hard to understand.
            You obviously skimmed this paper, saw something you don’t understand but you thought backed up your moon mining thing, and now you’re doubling down with your usual pile of quotes lifted out-of-context from other people’s work that you again – don’t understand. Carry on.

            • James

              se jones –

              “Of course, a smart space guy like James would know that free neutrons only last for 10 to 15 minutes, so it’s not likely a neutron flux would be a problem in deep space.”

              If you could read before you typed foolish sarcasm, you would realize that “a neutron flux would be a problem in deep space” if NASA used massive amounts of shielding to protect astronauts from dangerously high energy heavy ions traveling at near light speeds.

              “CR secondary particle shower species, especially neutrons, dominate effects on electronic systems and human health at high shielding mass”

              And, “Slow accumulation of whole body dose from GCR (expressed in Effective equivalent Sv) and including secondary particle showers in the human body) presently limits the duration of manned space operations outside earth’s magnetosphere to times on the order of 180 days (assuming 20 to 30 g/cm2shielding mass).”

              From: ‘Practical Applications of Cosmic Ray Science: Spacecraft, Aircraft, Ground Based Computation and Control Systems and Human Health and Safety’
              By Steve Koontz – NASA, Johnson Space Center, Houston, Texas Spring 2015

              NASA cannot do a Mars mission in “180 days”.

              ‘Space is a dangerous place. A new report shows just how dangerous it could be to human brains. Radiation exposure from a Mars missions could cook brain cells, causing chronic dementia and memory loss, and leaving astronauts with debilitating anxiety levels, the study has found. This could throw off their thinking and judgment, impairing decision-making and multi-tasking.’

              From: ‘A Mission to Mars Could Cause Serious Brain Damage’
              By Prachi Patel Oct 10, 2016
              At: http://spectrum.ieee.org/the-human-os/aerospace/space-flight/mission-to-mars-could-cause-serious-brain-damage

              We lack the affordable shielding technology needed for NASA and international astronauts to do Mars missions.

              There doesn’t appear to be a great willingness in Congress to sacrifice NASA and international astronauts on the very costly altar of the President’s ill-conceived Lost in Space policy, and thus we get unhappy posts from those who are true believers in in the nonscientific ‘Mars Soon and Cheaply Too’ noise.

              Humans and robots are going to the affordable Moon to tap its resources to reduce the risks and costs of developing Cislunar Space and to develop the technology and infrastructure needed for sustainable missions to Mars, Ceres, and other Deep Space destinations.

            • James

              se jones –

              “You obviously skimmed this paper, saw something you don’t understand but you thought backed up your moon mining thing”.

              It is not my “moon mining thing” and someone would have to be pretty confused to make that nonsense claim.

              “Why the Moon before Mars?”
              “‘The Moon is a natural first step,’ explains Philip Metzger, a physicist at NASA Kennedy Space Center. ‘It’s nearby. We can practice living, working and doing science there before taking longer and riskier trips to Mars.'”

              And, “The Moon is also a good testing ground for what mission planners call ‘in-situ resource utilization’ (ISRU)–a.k.a. ‘living off the land.’ Astronauts on Mars are going to want to mine certain raw materials locally: oxygen for breathing, water for drinking and rocket fuel (essentially hydrogen and oxygen) for the journey home. ‘We can try this on the Moon first,’ says Metzger.”

              And, “Lunar ice, on the other hand, is localized near the Moon’s north and south poles deep inside craters where the Sun never shines, according to similar data from Lunar Prospector and Clementine, two spacecraft that mapped the Moon in the mid-1990s.”

              And, “If this ice could be excavated, thawed out and broken apart into hydrogen and oxygen … Voila! Instant supplies.”

              And, “Testing all this technology on the Moon, which is only 2 or 3 days away from Earth, is going to be much easier than testing it on Mars, six months away.”

              From: ‘En route to Mars, the Moon
              Why colonize the Moon before going to Mars?
              NASA scientists give their reasons.’
              March 18, 2005
              At: http://science1.nasa.gov/science-news/science-at-nasa/2005/18mar_moonfirst/

              “Warren Platts says:
              September 4, 2016 at 11:14 am
              In contrast to SpaceX’s attempt to reach up from Earth with greenhouse-gas emitting rockets, the ULA is seriously proposing to reach down from the Moon with lunar propellants. I was at the 7th joint meeting of The Space Resources Roundtable (SRR) and the Planetary & Terrestrial Mining Sciences Symposium (PTMSS) was held on June 7-9, 2016 at the Colorado School of Mines, in Golden, CO. There George Sowers made a concrete bid for lunar propellant: although they are not necessarily interested in the mining business themselves, they would be willing to take delivery of lunar-produced propellant at the Moon’s surface for ~$500K/mT (but it’s gotta be mass ratio 5).”

              From: Responses section of ‘Not Vaunted, Not Clever and Not Working – The State of America’s Space Program’ By Paul Spudis September 4, 2016
              At: http://www.spudislunarresources.com/blog/not-vaunted-not-clever-and-not-working-the-state-of-americas-space-program/

              The “moon mining thing” belongs to NASA and the space agencies and Moon and mining experts of many countries.

              As for me, I’m a former truck driver. However, I do accept that the Moon has lots of useful resources that are going to be worth mining.

              Concerning my expertise in mining, about the most I can claim is that as an eight-year-old kid I once climbed down alone into an abandoned mine. It was not the smartest thing to do, but then again I never claimed to run with the “smart” crowd, and I tend to leave various types of claims about being “smart” to the insecure folks who obviously need to bolster their fragile egos.

        • James

          “Slow accumulation of whole body dose from GCR (expressed in Effective equivalent Sv) and including secondary particle showers in the human body) presently limits the duration of manned space operations outside earth’s magnetosphere to times on the order of 180 days (assuming 20 to 30 g/cm2shielding mass).”

          And, The overall programmatic cost of the available active or passive shielding needed to extend that limit is likely prohibitive at this time”

          And, “The effects of energetic cosmic ray, solar particle event, and trapped radiation charged particles on contemporary electronic systems as well as human health and safety depends on:
          –The production of ionization/excitation tracks in target materials
          –Collisions with target material nuclei to initiate secondary particle showers”

          And, “CR secondary particle shower species, especially neutrons, dominate effects on electronic systems and human health at high shielding mass”

          From: ‘Practical Applications of Cosmic Ray Science: Spacecraft, Aircraft, Ground Based Computation and Control Systems and Human Health and Safety’
          By Steve Koontz – NASA, Johnson Space Center, Houston, Texas Spring 2015

          Yep, “at high shielding mass” Cosmic Ray “secondary particle shower species, especially neutrons, dominate effects on electronic systems and human health” isn’t all that difficult to understand.

          And “high shielding mass” is the only effective Galactic Cosmic Ray shielding we currently have against dangerously high energy heavy ions traveling at near light speeds, and iron appears to be an effective shielding material against any high energy neutrons produced both within the spacecraft and inside its iron Galactic Cosmic Radiation shielding material surrounding a small shelter habitation unit.

  • se jones

    Time to put in a good word for the dedicated folks who did the Lunar Orbiter Image Recovery Project (LOIRP).

    http://www.moonviews.com/

  • James

    “But Seattle billionaire Jeff Bezos has a different kind of off-Earth home in mind when he talks about having millions of people living and working in space.”

    And, “His long-range vision focuses on a decades-old concept for huge artificial habitats that are best known today as O’Neill cylinders.”

    And, “Bezos is said to have talked up the concept in the 1980s, when he was a starry-eyed student at Princeton. Three decades later, he’s the CEO of Amazon with a net worth estimated at $67 billion, and with his own space venture called Blue Origin.”

    And, “‘Then we get to see Gerard O’Neill’s ideas start to come to life, and many of the other ideas from science fiction,’ Bezos said. ‘The dreamers come first. It’s always the science-fiction guys: They think of everything first, and then the builders come along and they make it happen. But it takes time.'”

    From: ‘Where does Jeff Bezos foresee putting space colonists? Inside O’Neill cylinders’
    By Alan Boyle
    October 30, 2016
    At: https://www.yahoo.com/news/where-does-jeff-bezos-foresee-164436281.html

    To build enormous O’Neill cylinders in Cislunar Space it could be quite useful to be able to cheaply launch into Lunar orbit steel alloys from the Moon using railguns that can currently shoot projectiles at a velocity of 1.26 miles (or over 2 kilometers) per second.

    Note also:

    “Today a team of material scientists at Pohang University of Science and Technology in South Korea announced what they’re calling one of the biggest steel breakthroughs of the last few decades: an altogether new type of flexible, ultra-strong, lightweight steel. This new metal has a strength-to-weight ratio that matches even our best titanium alloys, but at one tenth the cost, and can be created on a small scale with machinery already used to make automotive-grade steel.”

    And, “That’s remarkable, but Kim insists that the method is actually more important than the result. Now that his results are published, he expects scientists to cook up a multitude of new alloys based on the B2-dispersion method.”

    From: ‘Scientists Invent a New Steel as Strong as Titanium
    South Korean researchers have solved a longstanding problem that stopped them from creating ultra-strong, lightweight aluminum-steel alloys.’
    By William Herkewitz Feb 4, 2015
    At: http://www.popularmechanics.com/technology/news/a13919/new-steel-alloy-titanium/

    “An O’Neill cylinder would consist of two counter-rotating cylinders. The cylinders would rotate in opposite directions in order to cancel out any gyroscopic effects that would otherwise make it difficult to keep them aimed toward the Sun. Each would be 5 miles (8.0 km) in diameter and 20 miles (32 km) long, connected at each end by a rod via a bearing system.”

    And, “To save the immense cost of rocketing the materials from Earth, these habitats would be built with materials launched into space from the Moon with a magnetic mass driver.[1]”

    From: ‘O’Neill cylinder’ at: Wikipedia

    Building lots of O’Neill cylinders sounds pretty good to me.

  • Gary Church

    Hydrogen is the best radiation shielding. Water is the simplest and most utilitarian. Water contained in plastic structures is a good mix. James does not seem to have a good understanding of the properties of the heavy nuclei component of GCR and having to side with the arrogant cur in this is distasteful.

    What is most unsettling is the NewSpace creeps that consistently, and predictably, trivialize radiation as far down the list of things to worry about after the truly important matter of making sure their John Galt/Tony Stark hero conquers the universe. Pathetic.

    The best guide to understanding radiation and human space flight is the Scientific American article “Shielding Space Travelers” by Eugene Parker.