Ever since a study conducted back in 1993, it has been proposed that in order for a planet to support more complex life, it would be most advantageous for that planet to have a large moon orbiting it, much like the Earth’s moon. Our moon helps to stabilize the Earth’s rotational axis against perturbations caused by the gravitational influence of Jupiter. Without that stabilizing force, there would be huge climate fluctuations caused by the tilt of Earth’s axis swinging between about 0 and 85 degrees.
But now that belief is being called into question thanks to newer research, which may mean that the number of planets capable of supporting complex life could be even higher than previously thought.
Since planets with relatively large moons are thought to be fairly rare, that would mean most terrestrial-type planets like Earth would have either smaller moons or no moons at all, limiting their potential to support life. But if the new research results are right, the dependence on a large moon might not be as important after all. “There could be a lot more habitable worlds out there,” according to Jack Lissauer of NASA’s Ames Research Center in Moffett Field, California, who leads the research team.
It seems that the 1993 study did not take into account how fast the changes in tilt would occur; the impression given was that the axis fluctuations would be wild and chaotic. Lissauer and his team conducted a new experiment simulating a moonless Earth over a time period of 4 billion years. The results were surprising – the axis tilt of the Earth varied only between about 10 and 50 degrees, much less than the original study suggested. There were also long periods of time, up to 500 million years, when the tilt was only between 17 and 32 degrees, a lot more stable than previously thought possible.
So what does this mean for planets in other solar systems? According to Darren Williams of Pennsylvania State University, “Large moons are not required for a stable tilt and climate. In some circumstances, large moons can even be detrimental, depending on the arrangement of planets in a given system. Every system is going to be different.”
Apparently the assumption that a planet needs a large moon in order to be capable of supporting life was a bit premature. The results so far from the Kepler mission and other telescopes have shown that there is a wide variety of planets orbiting other stars, and so probably also moons, which we are now also on the verge of being able to detect. It’s nice to think that more of the terrestrial-type rocky planets, with or without moons, might be habitable after all.
The Phobos-Grunt mission profile. Credit: Roscosmos
[/caption]
Editor’s note: Dr. David Warmflash, principal science lead for the US team from the LIFE experiment on board the Phobos-Grunt spacecraft, provides an update for Universe Today on the likelihood of saving the mission.
If communication with Russia’s troubled Phobos-Grunt is not established by November 21, the window for a trajectory to the Martian moon Phobos, will close, experts say. But this would not mean that the spacecraft could not travel to a different destination. In a statement published earlier today by the news and information agency Ria Novosti, Russian space expert Igor Lisov suggested that Phobos-Grunt could be sent to orbit the Moon – Earth’s Moon, that is – or may be even an asteroid, if communication is restored at any point before the 13-ton probe re-enters Earth’s atmosphere.
Evolution of Phobos-Grunt’s Orbit
Boosted into space by a Zenit 2 rocket last week, Phobos-Grunt entered into a low parking orbit, where she was supposed to wait only for 2.5 hours before the next booster stage, Fregat, would send her to a higher orbit and then on to Mars. Because the Fregat engine did not ignite, Grunt still orbits just above our heads. “Highly elliptical, with an initial altitude of 347 kilometers at apogee (the high point) and 207 kilometers at perigee (the low point), the orbit initially was predicted to decay by late November, causing the spacecraft to reenter the atmosphere and burn up. But while the apogee has been decreasing (down to 326 km today), the perigee actually has been increasing by about 0.5 kilometers per day (up to 210.2 km today), due to periodic maneuvering by way of the probe’s small thrusters. After it was realized that the first maneuvering episode had improved the orbit, the predicted reentry date was adjusted to mid January, and if the thrusting episodes continue we can expect the date of the probe’s demise to be moved back still more.
An artists concept of the Phobos-Grunt Mission. Credit: Roscosmos
Time for Trajectory to Phobos is Running Out
The improved orbit gives controllers at the Russian Space Agency, Roscosmos, several weeks –even more, if the perigee continues to get higher– to restore communication with Phobos-Grunt, allowing for the uploading of new commands. But, even if control is restored, a flight to Mars and Phobos will not be possible after Monday, November 21st, Lisov explained. Although the Fregat stage is loaded with fuel, to reach Mars, given Grunt’s orbit around Earth and the alignment between Earth and Mars after Monday, would require a higher change in velocity –what propulsion specialists call delta v – than the Fregat is capable of producing.
A Consolation Prize
While cautioning that the idea of sending Phobos-Grunt somewhere other than Phobos falls into the realm of wishful thinking, Lisov urged that efforts to reconnect with the spacecraft continue in full force as long as the craft is in space. Despite several failures of lunar missions, the former Soviet space program did succeed in returning samples from the lunar surface to Earth in the 1970s. Thus, re-purposing the current mission as “Luna-Grunt” or something of that nature is not likely to have the same appeal as Phobos-Grunt has among Russians. Nor could the Grunt landing craft, designed to scoop a surface sample into a capsule that would return to Earth, even set down on the lunar surface. But other components of the science payload might be useful. Though built to observe Mars,China’s Yinghuo-1 orbiter might be able to do something interesting from lunar orbit. Instruments that were to remain on the Phobosian surface might be useful as well.
Then, there is the issue of avoiding reentry. Experts at Roscosmos are confident that the many tons of nitrogen teroxide and hydrazine in Grunt’s fuel tanks will burn up high in the atmosphere if the probe reenters. But people around the planet are scared, and thus might prefer that the fuel be used, even for a one-way mission with undefined science objectives. More importantly, achieving in a partial victory by sending the spacecraft anywhere but back to Earth could give rise to an Apollo 13-like milieu that might reinvigorate the Russian planetary program.
Millions of Tiny Passengers
The Planetary Society’s Living Interplanetary Flight Experiment (LIFE) capsule, on board the Phobos-Grunt spacecraft. Credit:The Planetary Society
As I’ve discussed in a previous update, to be useful scientifically, the Planetary Society’s Living Interplanetary Flight Experiment (LIFE) rides inside the capsule that was designed to return the Phobosian sample to Earth. The point of the experiment is to test the effects of the space environment on several different types of organisms. Because the Moon orbits Earth far outside the Van Allen radiation belts, the radiation received per time by organisms on lunar flights is the same as that received during flights to Mars. If the capsule could be sent into lunar orbit, our millions of passengers would be like organisms traveling inside a meteoroid from Mars. Then perhaps some future mission could recover the capsule some day, and we could study the organisms, as we planned to do upon their return from Phobos.
A Possible Asteroid Mission
Lisov also speculated about sending the Grunt spacecraft to an asteroid instead of the Moon. Various asteroids travel fairly close to Earth, and it’s plausible that a Grunt probe revived after November 21 would have enough delta v to reach one of them. Unlike Earth’s Moon, whose gravity the Grunt lander was not designed to withstand, many asteroids are small. Theoretically, Grunt’s lander could set down on any celestial body with a gravitational force similar to that of Phobos. If any such asteroid candidate exists –and this is a big if– the ascent engine, designed to propel the Grunt return capsule back to Earth might be utilized to deliver a sample of the asteroid, along with the LIFE experiment.
When the distance from the Earth to the Moon comes up, the common figure thrown around is 402,336 km (or 250,000 miles). But have you every wondered how astronomers got that figure? And how exact it really is? There are a couple of ways you can measure the distance of the Moon that don’t require lasers or any instruments. All you need are your eyes, a clear sky, and someone else willing to stand outside all night with you.
There are two ways to measure the distance from the Earth to the Moon on your own: using a Lunar eclipse and using parallax. Let’s look at eclipses first.
The phases of a Lunar eclipse. Photo credit: Keith Burns for NASA/JPL
The Ancient Greeks used Lunar eclipses – the phenomena of the Earth passing directly between the sun and the Moon – to determine the distance from the Earth to its satellite. It’s a simple matter of tracking and timing how long it takes the Earth’s shadow to cross over the Moon.
Start with the few knowns. We know, as did the Ancient Greeks, that the Moon travels around the Earth at a constant speed – about 29 days per revolution. The diameter of the Earth is also known to be about 12,875 km or 8,000 miles.By tracking the movement of the Earth’s shadow across the Moon, Greek astronomers found that the Earth’s shadow was roughly 2.5 times the apparent size of the Moon and lasted roughly three hours from the first to last signs of the shadow.
From these measurements, it was simple geometry that allowed Aristarchus (c. 270 BC) to determined that the Moon was round 60 Earth radii away (about 386,243 km or 240,000 miles). This is quite close to the currently accepted figure of 60.3 radii.
You can follow Aristarchus’ method in your own backyard if you have a clear view of a Lunar eclipse. Track the movement of the Earth’s shadow on the Moon by drawing the changes and time the eclipse. Use your measurements to determine the Moon’s distance.
Lunar parallax: the moon as observed from Italy and China at the same time during a lunar eclipse. Photo credit: measurethemoon.org/wordpress
For the second method, you’ll need a friend to help out. The Ancient Greeks also knew about parallax, an object’s apparent change in position when seen from two different viewpoints. You can experience parallax by holding a pen out at arm’s length and looking at it with one eye at a time. As you switch between your left and right eye, the pen will appear to move back and forth.
The same thing can be seen on a giant scale. Two observers in different parts of the world (at least 3,200 km or 2,000 miles apart) will see the Moon’s position as different from where calculations say it should be in the night sky.
To find the distance of the Moon from the Earth, you and a friend stand 3,200 km apart and each take a picture of the Moon at exactly the same time. Then, compare your images. The Moon will be in a different spot, but the background stars will be in the same place. What your images have given you is a triangle. You know the base (the distance between you and your friend), and you can find the angle at the top (the point of the Moon in this triangle). Simple geometry will give you a value for the distance of the Moon.
It might be a little more labour intensive than searching the internet, but determining the Moon’s distance yourself is sure to be more fun! If you really want to get involved, check out International Measure the Moon Night on Dec. 10, 2011. Join participants around the world who register their own events and share their images and observations!
A graph showing which parts of the world have the best chance of measuring the moon's distance using these two methods. Regions in red can see full eclipses while regions covered in red bars are best suited to measurements using parallax. Photo credit: measurethemoon.org/wordpress
Lunar Reconnaissance Orbiter Wide Angle Camera color shaded relief of the lunar farside (NASA/GSFC/DLR/Arizona State University).
[/caption]
You’re looking at a brand new view of the lunar farside, as never seen before. The team from the Lunar Reconnaissance Orbiter has released the first version of a topographic map of nearly the entire Moon, from data from the Wide Angle Camera (WAC) on the spacecraft.
“This amazing map shows you the ups and downs over nearly the entire Moon, at a scale of 100 meters across the surface, and 20 meters or better vertically,” said principal investigator Mark Robinson, writing on the LROC website. “Despite the diminutive size of the WAC (it fits in the palm of one’s hand), it images nearly the entire Moon every month.”
Every month? So why is this a “new” map since LRO has been in lunar orbit since mid-2009?
Robinson said that each month the Moon’s lighting changes, so the WAC methodically builds up a record of how different rocks reflect light under different conditions, and adds to the LROC library of stereo observations.
“The WAC really is the little camera that could!” Robinson said.
Left: LROC Wide Angle Camera attached to a test setup shortly before mounting on the spacecraft. Right: WAC being handed up to engineers for integration with LRO. Photos courtesy Mark Robinson, via the LROC website.
It is very similar to the MARCI camera (Mars Color Imager) on the Mars Reconnaissance Orbiter, another wide-angle, low-resolution camera specially built for orbital observations; both cameras were built by Malin Space Science Systems.
Topographic maps provide a detailed and accurate graphic representation of natural features on the ground, and Robinson this new map of the Moon will help both lunar scientists and future explorers on the Moon.
Combing data from the WAC along with the LRO Lunar Orbiter Laser Altimeter (LOLA), the scientists are able to provide a topographic map of nearly the entire Moon. Due to persistent shadows near the poles it is not possible to create a complete WAC stereo map at the very highest latitudes, but LOLA provides a very high resolution topographic model of the poles.
How is a digital topographic map created from stereo images? The WAC stereo images were compared one against another by pattern-matching a moving box of pixels until the best fit was found between two images with different viewing angles. The new topographic model was constructed from 69,000 WAC stereo models.
Robinson and his team are already looking towards improvements they can make with subsequent versions of their topographic maps.
“The current model incorporates the first year of stereo imaging, and there is another year of data that can be added to the solution,” he said. “These additional stereo images will not only improve the sharpness (resolution) of the model but also fill in very small gaps that exist in the current map. The LROC team has made small improvements to the camera distortion model, and the LOLA team has improved our knowledge of the spacecraft position over time. These next generation steps will further improve the accuracy of Version 2 of the LROC GLD100 topographic model of the Moon.”
You can see the “zoomable” full resolution versions of the new map for both the far and near side at this link.
Chaos terrain on Europa points to subsurface lakes, new research suggests. (NASA/JPL/Ted Stryk)
[/caption]
New research on Jupiter’s ice-covered moon Europa indicates the presence of a subsurface lake buried beneath frozen mounds of huge jumbled chunks of ice. While it has long been believed that Europa’s ice lies atop a deep underground ocean, these new findings support the possibility of large pockets of liquid water being much closer to the moon’s surface — as well as energy from the Sun — and ultimately boosting the possibility it could contain life.
During a press conference today, November 16 at 1 p.m. EST, researchers Britney Schmidt, Tori Hoeler, Louise Prockter and Tom Wagner presented new theories concerning the creation of “chaos terrain” on Europa.
Chaos terrain is exactly what it sounds like: irregularly-shaped landforms and surface textures on a world. In the case of Europa, the terrain is made of water ice that evidence shows has been loosened by the motion of liquid water beneath, expanded, and then has refrozen into hills and jagged mounds.
Topographic data shows the chaos terrain elevations above the surrounding surface. Reds and purples are the highest elevations. Credit: NASA
These mounds are visible in topographic data acquired by the Galileo spacecraft in 1998.
During the presentation a good analogy for the processes at work on Europa was made by Britney Schmidt, a postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin and lead author of the paper. She demonstrated the formation of Europa’s “mosh pit of icebergs” using a drinking glass partially filled with ice cubes. When water was added to the glass, the ice cubes naturally rose up and shifted orientation. Should the water beneath them refreeze, as it would in the frigid environments found in the Jovian system, the ice cubes would be held fast in their new expanded, “chaotic” positions.
“Now we see evidence that it’s a thick ice shell that can mix vigorously, and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable.”
– Britney Schmidt, lead author
Similar processes have also been seen occurring on Earth, both in Antarctica along the edges of ice shelves and in Greenland, where glaciers continually break apart and flow into the sea – often rolling over themselves and each other in the process.
Europa's "Great Lake." Scientists speculate many more exist throughout the shallow regions of the moon's icy shell. Image Credit: Britney Schmidt/Dead Pixel FX/Univ. of Texas at Austin.
The importance of these findings is that scientists finally have a model that demonstrates how Europa’s deep liquid ocean interacts with the ice near its surface in such a way as to allow for the transportation of energy and nutrients.
“This is the first time that anyone has come up with an end-to-end model that explains what we see on the surface,” said APL senior planetary scientist Louise Prockter.
With such strong evidence for this process, the likelihood that Europa could harbor environments friendly to life goes up dramatically.
“The potential for exchange of material between the surface and subsurface is a big key for astrobiology,” said Wes Patterson, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and a co-author of the study. “Europa’s subsurface harbors much of what we believe is necessary for life but chemical nutrients found at the surface are likely vital for driving biology.”
Although the research favors the existence of these lakes, however, confirmation of such has not yet been found. That will require a future mission to Europa and the direct investigation of its icy surface – and what lies beneath.
Luckily a Europa mission was recently rated as one of the highest priority flagship missions by the National Research Council’s Planetary Science Decadal Survey and is currently being studied by NASA.
“If we’re ever to send a landed mission to Europa, these areas would be great places to study,” Prockter said.
Read more about this discovery in the Johns Hopkins University Applied Physics Laboratory press release, or in the NASA news release here. Also, watch the full conference recorded on Ustream below:
Apollo 17 astronaut Harrison "Jack" Schmitt at Tracy Rock on the lunar surface. If a solar storm had hit the Moon while the astronauts were on the surface exploring, it could have been a disaster. Credit: NASA.
[/caption]
It’s been a mystery ever since the Apollo astronauts brought back samples of lunar rocks in the early 1970s. Some of the rocks had magnetic properties, especially one collected by geologist Harrison “Jack” Schmitt. But how could this happen? The Moon has no magnetosphere, and most previously accepted theories state that it never did. Yet here we have these moon rocks with undeniable magnetic properties… there was definitely something missing in our understanding of Earth’s satellite.
Now a team of researchers at the University of California, Santa Cruz thinks they may have cracked this enigmatic magnetic mystery.
In order for a world to have a magnetic field, it needs to have a molten core. Earth has a multi-layered molten core, in which heat from the interior layer drives motion within the iron-rich outer layer, creating a magnetic field that extends far out into space. Without a magnetosphere Earth would have been left exposed to the solar wind and life as we know it could may never have developed.
Apollo 17 lunar rock sample
Simply put, Earth’s magnetic field is crucial to life… and it can imbue rocks with magnetic properties that are sensitive to the planet-wide field.
But the Moon is much smaller than Earth, and has no molten core, at least not anymore… or so it was once believed. Research of data from the seismic instruments left on the lunar surface during Apollo EVAs recently revealed that the Moon may in fact still have a partially-liquid core, and based on a paper published in the November 10 issue of Nature by Christina Dwyer, a graduate student in Earth and planetary sciences at the University of California, Santa Cruz, and her co-authors Francis Nimmo at UCSC and David Stevenson at the California Institute of Technology, this small liquid core may once have been able to produce a lunar magnetic field after all.
The Moon orbits on its axis at such a rate that the same side always faces Earth, but it also has a slight wobble in the alignment of its axis (as does Earth.) This wobble is called precession. Precession was stronger due to tidal forces when the Moon was closer to Earth early in its history. Dwyer et al. suggest that the Moon’s precession could have literally “stirred” its liquid core, since the surrounding solid mantle would have moved at a different rate.
This stirring effect – arising from the mechanical motions of the Moon’s rotation and precession, not internal convection – could have created a dynamo effect, resulting in a magnetic field.
This field may have persisted for some time but it couldn’t last forever, the team said. As the Moon gradually moved further away from Earth the precession rate slowed, bringing the stirring process – and the dynamo – to a halt.
“The further out the moon moves, the slower the stirring, and at a certain point the lunar dynamo shuts off,” said Christina Dwyer.
Still, the team’s model provides a basis for how such a dynamo could have existed, possibly for as long as a billion years. This would have been long enough to form rocks that would still exhibit some magnetic properties to this day.
The team admits that more paleomagnetic research is needed to know for sure if their proposed core/mantle interaction would have created the right kind of movements within the liquid core to create a lunar dynamo.
“Only certain types of fluid motions give rise to magnetic dynamos,” Dwyer said. “We calculated the power that’s available to drive the dynamo and the magnetic field strengths that could be generated. But we really need the dynamo experts to take this model to the next level of detail and see if it works.”
In other words, they’re still working towards a theory of lunar magnetism that really sticks.
[/caption]
Logan Mancuso captured this photo of the Moon on August 16th, 2011 at Cherry Springs State Park, Coudersport, PA. The Moon was at illuminated Fraction 0.883 – 3.5 days after full moon when imaged.
Logan also provided us with the camera and specs he used in taking the photo:
Telescope: LX200GPS
Camera: Canon EOS Rebel 1000D at prime focus, F/0.0, ISO 800, 1/30 sec.
Conditions: near perfect seeing and transparency, and no clouds
Want to get your astrophoto featured on Universe Today? Join our Flickr group, post in our Forum or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
A collection of Moon rock samples that NASA uses for eduction. A similar type sample was invovlved in the recent sting operation. Credit: NASA
[/caption]
A 74-year-old grandmother was taken into custody after a NASA sting operation to recover a small shard of a Moon rock. In an Associated Press article, Joanna Davis said the Moon rock was given to her husband by Neil Armstrong in the 1970s, and she was trying to sell the item to take care of her sick son. However, any samples from the Moon are considered government property, and so cannot be sold for profit.
But no charges have been filed and NASA is not commenting on the case.
Davis said she was frightened and bruised during the incident that occurred at a Denny’s restaurant
“They grabbed me and pulled me out of the booth,” Davis told the AP.
Reportedly Davis emailed a NASA contractor on May 10, 2011 trying to find a buyer for the rock, as well as a nickel-sized piece of the heat shield that protected the Apollo 11 space capsule as it returned to earth from the Apollo 11 mission to the moon in 1969.
Neil Armstrong has said previously in a written affidavit that he has never given Moon rocks to private citizens.
While Davis’s attorney called the incident “abhorrent behavior by the federal government to steal something from a retiree that was given to her,” according to AP, Davis apparently knew that what she was doing was against the law.
Artist concept of a settlement on the Moon. Credit: NASA/Pat Rawlings
[/caption]
It’s long been a dream to have a human settlement on the Moon, but in this age of budget cuts and indecisive plans for NASA’s future, a Moon base may seem too costly and beyond our reach. However, noted lunar scientist Dr. Paul Spudis from the Lunar and Planetary Institute and a colleague, Tony Lavoie from the Marshall Space Flight Center, have come up with a plan for building a lunar settlement that is not only affordable but sustainable. It creates a Moon base along with a type of ‘transcontinental railroad’ in space which opens up cislunar space – the area between Earth and the Moon – for development.
“The ultimate goal in space is to be able to go anywhere, anytime with as much capability as we need,” Spudis told Universe Today. “This plan uses a robotic and human presence on the Moon to use the local resources to create a new spacefaring system. The key for doing this is to adopt a flexible approach that is incremental and cumulative.”
In a nutshell what Spudis proposes is to send robots to the Moon which are tele-operated from Earth to start extracting water from the polar deposits to create propellant. The propellant would be used to fuel a reusable space transportation system between the Earth and the Moon.
“The reason this is possible is because the Moon is close – it’s only three light-seconds round trip for radio signal get from Earth to the Moon back,” Spudis said, “which means you can control machines remotely with operators on the Earth actually doing the activities that an astronaut might do on the Moon.”
A lunar mining facility harvests oxygen from the resource-rich volcanic soil of the eastern Mare Serenitatis.Credit: NASA/Pat Rawlings.
The advantage here is that a large part of the needed infrastructure, such as the mining operation, the processing plants, the development of storage for the water and propellant, is created before people even arrive.
“So what we try to do is to develop an architecture that enables us to, first, do this in small, incremental steps, with each step building upon the next, and the net effect is cumulative over time,”Spudis said. “And finally we are able to bring people to the Moon when we’re ready to actually have them live there. We place an outpost — a habitat — that will be fully operational before the first humans arrive.”
The significant amount of water than has been found on the Moon at the poles makes this plan work.
“We estimate there are many tens of billions of tons of water at both poles,” Spudis said. “What we don’t know in detail is exactly how much water is distributed what physical state it is in, and that’s one of the reasons why the first step in our plan is to send robotic prospectors up there to map the deposits and see how they vary.”
Water is an important resource for humans in space: it supports life for drinking and cooking, it can be broken down into oxygen for breathing, and by combing the oxygen and hydrogen in a fuel cell, electricity can be generated. Water is also a very good shielding material that could protect people from cosmic radiation, so the habitat could be “jacketed” with water.
But the most important use of water is being able to create a powerful chemical rocket propellant by using the oxygen and hydrogen and freezing them into a liquid.
“The Moon offers us this water not only to support human life there, but also to make rocket propellant to allow us to refuel our spacecraft both on the Moon and space above the Moon.”
In a series of 17 incremental missions, a human base would be built, made operational and occupied. It starts with setting up communication and navigation satellites around the Moon to enable precision operation for the robotic systems.
Next would sending rover to the Moon, perhaps a variant of the MER rovers that are currently exploring Mars, to prospect the best places for water at the lunar poles. The poles also provide areas of permanent sunlight to generate electrical power.
Next, larger equipment would be sent to experiment with digging up the ice deposits, melting the ice and storing the products. (See our previous article about using bulldozers on the Moon).
“Now, all those are simple conceptually, but we’ve never done them in practice,” said Spudis, “so we don’t know how difficult it is. But by sending the small robotic missions to the Moon and practicing this via remote control from Earth, we can evaluate how difficult it is — where the chokepoints are — and what are the most efficient ways to get to these deposits and to extract usable a product from them.”
The next step is to increase the magnitude of the effort by landing bigger robotic machines that can actually start making product on industrial scales so that a depot of supplies can be stockpiled on the Moon for when the first human humans to return to the Moon.
Cislunar space. Graphic courtesy Paul Spudis.
In the meantime, a constant transportation system between Earth and Moon would be created, with another system that goes between the Moon and lunar orbit, which opens up all kinds of possibilities.
“The analogy I like to make is this is very similar to the Transcontinental Railroad,” Spudis said. “We didn’t just build the Transcontinental Railroad to from the East Coast directly to the West Coast; we also built it to access all the points in between, which consequently were developed economically as well.”
By having a system where the vehicles are refueled from the resources extracted on the Moon, a system is created that routinely accesses the Moon and allows for returning to Earth, but all the other points in between can be accessed as well.
“We create a transportation system that accesses all those points between Earth and Moon. The significance of that is, much of our satellite assets reside there,” said Spudis, “ for example communication satellites and weather monitoring satellites reside in geosynchronous orbit, (about 36,000 km above the Earth’s equator) and right now we cannot reach that from low Earth orbit. If we have system that can routinely go back and forth to the Moon, we could also go to these high orbits where a lot of commercial and national security assets are.”
Spudis added that a fuel depot could go in various locations, including the L1 LaGrange point which would enable space flight beyond the Moon.
How long will this take?
“We estimate that we can create an entire turn-key lunar outpost on the Moon within about 15 to 16 years, with humans arriving about 10 years after the initial robotic missions go,” Spudis said. “The mining operation would produce about 150 tons of water per year and roughly 100 tons of propellant.
And do any new technologies or hardware have to be built?
“Not really,” said Spudis. “Effectively this plan is possible to achieve right now with existing technology. We don’t have any ‘unobtainium’ or any special magical machine that has to be built. It is all very simple outgrowths of existing equipment, and many cases you can use the heritage equipment from previous missions.”
And what about the cost?
Spudis estimates that the entire system could be established for an aggregate cost of less than $88 billion, which would be about $5 billion a year, with peak funding of $6.65 billion starting in Year 11. This total cost includes development of a Shuttle-derived 70 mT launch vehicle, two versions of a Crew Exploration Vehicles (LEO and translunar), a reusable lander, cislunar propellant depots and all robotic surface assets, as well as all of the operational costs of mission support for this architecture.
“The best part is that because we have broken our architecture into small chunks, each mission is largely self-contained and once it gets to the Moon it interacts and works with the pieces that are already there,” Spudis said.
And the budget would be flexible.
“We can do this project at whatever speed the resources permit,” Spudis said. “So if you have a very constrained budget with very low levels of expenditure, you can go you just go much more slowly. If you have more resources available you can increase the speed and increase the rate of asset emplacement on the Moon and do more in a shorter period of time. This architecture gets us back to the Moon and creates real capability. But the free variable is schedule, not money.”
Artist concept of a Moon base. Credit: NASA/Pat Rawlings.
Returning to the Moon is important, Spudis believes, because not only can we use the resources there, but it teaches us how to be a spacefaring civilization.
“By going to the Moon we can learn how to extract what we need in space from what we find in space,” he said. “Fundamentally that is a skill that any spacefaring civilization has to master. If you can learn to do that, you’ve got a skill that will allow you to go to Mars and beyond.”
Spectacular high Sun view of the Mare Tranquillitatis pit crater revealing boulders on an otherwise smooth floor. Image is 400 meters wide, north is up, NAC M126710873R [NASA/GSFC/Arizona State University].
For the time being, it appears NASA has set aside any ambitions to return to the Moon with human missions. But Russia may consider sending cosmonauts to the lunar surface to set up a colony using natural caves and possible volcanic tunnels as protection from the harsh lunar environment.
“If it turns out that the Moon has a number of caves that can provide some protection from radiation and meteor showers, it could be an even more interesting destination than previously thought,” said veteran cosmonaut Sergei Krikalev, quoted in an article by Reuters.
Krikalev served on board two different space stations and flew on the space shuttle. He now leads Russia’s Star City cosmonaut training center outside Moscow. He and Russian scientists discussed the possible Moon base a forum on the future of manned spaceflight.
The image above is from the Lunar Reconnaissance Orbiter showing a cave or pit found in the Sea of Tranquility. Scientists have estimated the depth of the pit at over 100 meters, and several other caves have been found with orbiting spacecraft. Lunar scientists are studying the images to determine if an extended lava tube system still exists beneath the surface.
“This new discovery that the moon may be a rather porous body could significantly alter our approach to founding lunar bases,” said Krikalev. “There wouldn’t be any need to dig the lunar soil and build walls and ceilings. It would be enough to use an inflatable module with a hard outer shell to — roughly speaking — seal the caves.”
Reuters quoted Russian scientist Boris Kryuchkov as saying the first such lunar colonies could be built by 2030.
Sergei Krikalev works aboard the Interrnational Space Station. Credit: NASA
Krikalev has more than two years cumulative time in space His first long-duration flight to the Soviet space station Mir was in 1988, and he did back-to-back increments on Mir flight starting in May 1991 and returning to Earth in March 1992. While he was in orbit, the Soviet Union disintegrated and Mir became a Russian space station.
He became the first Russian to fly a Shuttle mission on STS-60 in February 1994. His second Shuttle flight took the Unity node to the International Space Station on STS-88 in December 1998. He was a member of the Station’s Expedition 1 crew, launching in October 2000 and returning to Earth in March 2001. He launched as commander of Expedition 11 in 2005.
Since planets with relatively large moons are thought to be fairly rare, that would mean most terrestrial-type planets like Earth would have either smaller moons or no moons at all, limiting their potential to support life. But if the new research results are right, the dependence on a large moon might not be as important after all. “There could be a lot more habitable worlds out there,” according to Jack Lissauer of NASA’s Ames Research Center in Moffett Field, California, who leads the research team.
