May 2, 2010
The Four Flavors of Lunar Water
Earth over the north pole of the Moon as seen from Clementine, 1994
The Moon is constantly bombarded by the solid debris of the Solar System. Comets, asteroids and interplanetary dust, all containing varying amounts of water, have pounded the lunar surface for billions of years. Yet until recently, the Moon was considered to be barren and bone-dry. Rock and soil samples returned by the Apollo missions lacked any hydrous mineral phases or water-bearing weathering products. Since water is not stable on the Moon under ordinary conditions, what happens to it?
New studies of lunar samples, along with results from several missions in recent years, have given us a revolutionary new picture of water on the Moon. Study of volcanic glass from the Apollo 15 landing site in 2008 demonstrated that tiny amounts of water (about 50 parts per million) are present in the interiors of these glasses, suggesting that the lunar mantle (whence they came) contains about ten times this amount. This was a startling result, considering the extreme dryness of other lunar samples.
Because the Moon’s spin axis is nearly perpendicular (1.5° from vertical) to the ecliptic plane, the Sun is always on the horizon at the poles, keeping the floors of deep craters in permanent shadow. These dark areas only receive heat from the interior of the Moon and are extremely cold; recent measurements by the DIVINER instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft indicate temperatures as cold as 25-35° C above absolute zero. Water molecules are trapped by the cold as soon as they find their way into these craters. Over the more than 4.5 billion years of lunar history, significant amounts of water could accumulate in many of these crater “cold traps” at the Moon’s poles.
The first hint of water ice in these polar cold traps came from a radio experiment aboard the 1994 Clementine mapping mission orbiting the Moon. The polarization characteristics of echoes from the south pole were consistent with the presence of ice in the crater Shackleton. Four years later, the Lunar Prospector (LP) spacecraft carried an instrument designed to measure the amount and energy of neutrons given off the Moon’s surface. Hydrogen absorbs neutrons, so when LP investigators saw a decrease in the flux of medium-energy neutrons near the lunar poles, they concluded that excess amounts of hydrogen were present there. Although this observation is consistent with the presence of polar ice, neutron data alone do not tell us what form the hydrogen is in, and it was alternatively postulated that this enhancement was caused by excess solar wind hydrogen.
The Moon Mineralogy Mapper (M3) instrument on the 2008-09 Indian Chandrayaan-1 mission collected reflectance spectra for most of the Moon. It found both water (H2O) and hydroxyl (OH) molecules, present either as a monolayer on lunar dust grains or bound into the mineral structures in surface materials, poleward of about 65° latitude at both poles. Moreover, the abundance of this surface water varies with time, being present in greater quantity in both local early morning and late evening and it increases in abundance with increasing latitude. These results were verified by observations from the Cassini and EPOXI spacecraft during separate flybys of the Moon. The new observations indicate significant quantities of water moving towards areas with lower mean surface temperatures and increasing in abundance with latitude. Taken all together, the results mean that water is being deposited (e.g., by comet impact) and/or created (e.g., by reduction of metal oxides in the surface by solar wind protons) and then transported to the poles. By this process, significant quantities of water ice could accumulate at the poles over geological time.
Last October, the companion satellite to LRO, LCROSS, slammed the upper stage of its launch vehicle into the Moon’s south pole and observed the ejected material. Results show that both water vapor and ice particles were ejected from the LCROSS impact crater; initial analyses indicate that water is present at about the 5-10 wt.% level. The LCROSS impact site exhibits no anomalous radar behavior, suggesting that such an amount of water ice cannot be detected by radar. However, the results do indicate that significant amounts of lunar polar water may be present even in the absence of specific radar evidence for it. Spectra from this impact event show evidence for other volatile substances, including ammonia and simple carbon compounds. The presence of such material may indicate a cometary source for these volatile materials.
Both poles were covered by radar images from the Mini-SAR instrument on Chandrayaan-1. Much of the north polar region displays backscattering properties typical for the ordinary Moon, but one group of craters in the region show elevated polarization enhancements in their interiors, but not in deposits exterior to their rims. Almost all of these anomalous craters are in permanent sun shadow and correlate with proposed locations of ice modeled on the basis of the Lunar Prospector neutron data. These relations suggest that the interiors of these craters contain nearly pure water ice, with approximately 600 million metric tonnes of ice present in over 40 small craters within 10 degrees of the pole. The south polar region shows similar relations, except that it has fewer anomalous craters than the north pole. Small areas of polarization enhancement are found in some craters, notably Shoemaker, Haworth and Faustini; these areas might be deposits of water ice.
So water on the Moon is present in large quantity in at least four different “flavors.” Water was in the deep lunar interior 3.3 billion years ago, at concentration levels of a few hundred parts per million. This water would have been released during the eruption of lunar magma and could have made its way into the polar cold traps. Water is either being made or being deposited nearly continuously by impact all over the Moon. Most of this water is subsequently lost to space (e.g., by sputtering, ionization or thermal escape) but some is retained on the Moon. Any water arriving at a cold trap near the pole will be captured. Water, once in the polar areas, is stable as ice in the permanent darkness or where sublimation is prevented when buried by a thin layer of soil. Significant quantities of water may accumulate there; the LCROSS results suggest several to tens of weight percent water ice may exist in the polar soils. Finally, some of this migrating water apparently collects at rates high enough so that significant soil cannot mix with it during normal impact bombardment, as shown by the presence of relatively “pure” water ice deposits in selected lunar craters imaged by radar.
A significant amount of water at the poles of the Moon is present, with many billions of metric tonnes at each pole (detailed estimates of the water reserves are in progress). Such an amount is more than enough to support both permanent, sustainable human presence on the Moon and for export to cislunar space. Water is useful as rocket fuel and energy storage (hydrogen and oxygen are the two most powerful chemical propellants known) and for life support (water and oxygen) in space. These new discoveries fundamentally alter our understanding of the Moon’s processes and history and highlight both it’s scientific value and utilization potential. The Moon is on the critical path to human expansion into the Solar System.
Addendum. In the comments below, reader Pradeep Mohandas reminds me about the findings of the Moon Impact Probe, released from Chandrayaan-1, which discovered water vapor in very small concentrations in the space just above the Moon during its descent to the south pole. This exospheric water (i.e., water in extremely small concentrations) may be related to the time-variable water seen in the spectral data from M3, Cassini, and EPOXI — in other words, it may represent water molecules in motion, migrating toward the poles. Work on the nature and processes of the lunar hydrosphere continues and I will keep you up to date on the latest research results on this new and exciting subtopic of lunar science.
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Pingback by Tweets that mention The Four Flavors of Lunar Water | The Once and Future Moon -- Topsy.com — May 2, 2010 @ 9:10 am
It’s not exactly a surprise to hear that there is some form of water on the Moon, but is there enough to support a lunar colony. 600 million tons of water isn’t really all that much, especially since it would be very hard to extract. I want Man to get out into space. Does knowing that there is ice at the Moon’s poles give us a sufficient reason to construct rockets and go there? Does it give us a good reason te establish a base or build a lunar colony? These things need to be done.
Comment by Ken St. Andre — May 2, 2010 @ 10:15 am
Ken,
It’s not exactly a surprise to hear that there is some form of water on the Moon
It was to about 95% of working lunar scientists. We’ve been debating and fighting about this since 1996.
600 million tons of water isn’t really all that much, especially since it would be very hard to extract… Does knowing that there is ice at the Moon’s poles give us a sufficient reason to construct rockets and go there?
It’s a considerable quantity. If all of it were converted to LOX-LH2 fuel, it is enough to launch the equivalent of a Space Shuttle, every day for over 2200 years. And if the radar data are any indication, it won’t be that hard to extract — just collect it with a bulldozer, separate the rock and soil debris and store it as block ice in a polar cold crater.
And the answer to your second question is “Yes.”
Comment by Paul D. Spudis — May 2, 2010 @ 10:57 am
hi,
So, what about the water vapour traced by the Moon Impact Probe in the lunar atmosphere which published article says the amount of water found in the atmosphere is 100 times than previously thought.
How would that fit into the lunar hydrology model?
Pradeep
Comment by Pradeep Mohandas — May 2, 2010 @ 1:20 pm
[...] in case you were wondering about the logistical challenges facing a lunar colony, wonder no longer! This article from the NASM (National Air and Space Museum) will tell you all you wish to know about all that [...]
Pingback by That High Wet Desert, the Moon « The Space Geek — May 2, 2010 @ 1:28 pm
The existence of water on the Moon and asteroids is indeed a remarkable discovery. But the question by the previous poster wasn’t really answered. Yes, if 600 million tons of water were converted into LOX-LH2, you’d have a lot of propulsion. But let’s extend that answer. On the Earth, there are 300 million •cubic miles• of water. (I’ll leave it to someone else to work out the tonnage. But it’s a LOT!) Now, if we converted all that into LOX-LH2, it would completely offset the higher gravitational force of the Earth compared to the Moon, and we could probably put the entire human race into space!
I’ll also suggest that it is vastly easier to extract water on the Earth compared to extracting water on the Moon. You don’t even need bulldozers! A bucket will do.
I’m not trying to be glib here, but just pointing out that explanations that rely on simplistic conversion resource estimates into capability aren’t necessarily convincing, especially when those capabilities aren’t unique.
Assuming that water on the Moon is intrinsically useful, a fair question might be the relative expense of refining water on the Moon compared to just taking it there. Putting a bulldozer on the Moon isn’t exactly cheap, especially one that has to move a huge amount of regolith to get a substantial amount of water. Putting a separation plant there might be kind of pricey as well.
Comment by Heinrich Monroe — May 2, 2010 @ 1:49 pm
Heinrich,
I do not mean to minimize the difficulties, but you are assuming an initial level of effort that implies more capability than is needed, at least initially. If the polar water is present in the quantities we estimate, a very small initial operation can harvest sufficient water to supply first the needs of the outpost, then to re-fuel the lunar lander, and finally make enough for export. A system that can collect and process a few metric tonnes per month is small and deliverable in one robotic landing. The machines needed can be teleoperated from Earth, something not possible for resource processing on asteroids or Mars.
People tend to have the impression that resource processing on the Moon requires a high level of industrial capability. Such is not the case; we start off small, use remote operations to build up an initial capability, and when people arrive, a resource processing infrastructure is already up and operating. It is then extended until needed capacity is reached.
Alternatively, we could just “study the technology” for ten years while doing nothing.
Comment by Paul D. Spudis — May 2, 2010 @ 2:56 pm
Extracting the oxygen alone from the lunar regolith would substantially reduce the cost of space travel within cis-lunar space and the cost of supplying space stations with oxygen for air and as a component of water.
Lunar sources of water, of course, would reduce those cost significantly more. Supplying space depots with oxygen and hydrogen from the Moon would be substantially cheaper than supply those resources from Earth. Lunar regolith and lunar water could also be used for mass shielding space stations and manned interplanetary vehicles from galactic radiation.
The addition of carbon and nitrogen resources from the lunar poles could, in theory, make a future industrialized lunar colony completely independent of the Earth’s resources.
So it is obvious that the first nation, or nations, to establish a permanent presence on the surface of the Moon will be the first to reap the economic benefits of utilizing lunar resources for reducing the cost of manned and unmanned space travel with the added benefit of economic gain from lunar tourism thanks to the reduced cost of traveling to the Moon.
Comment by Marcel F. Williams — May 2, 2010 @ 3:12 pm
@Heinrich Monroe
Its probably going to cost $50,000 to $100,000 per kilogram to send oxygen or water to the Moon from Earth. So I think its pretty obvious that a lunar base could manufacture oxygen from lunar regolith substantially cheaper than $50,000 per kilogram. And I think the same would be true if we extracted water from the lunar poles.
Comment by Marcel F. Williams — May 2, 2010 @ 3:49 pm
Pradeep,
So, what about the water vapour traced by the Moon Impact Probe
My presumption is that this water is the same water that M3 is detecting, only in motion — on its migration to the cold traps. But there is still much about the lunar “hydrosphere” that we don’t fully understand.
Thanks for reminding me about this observation. I have added an addendum to the article about it.
Comment by Paul D. Spudis — May 2, 2010 @ 5:50 pm
It’s a good thing Obama thinks the Moon is a been there done that destination..
Yes that was sarcasm!
Comment by Johnny — May 2, 2010 @ 9:24 pm
Hi Paul,
Many thanks for a very informative article, it is a subject I have been following for a long time.
One question though.
What does cislunar space mean in this context?
Cis according to my Latin dictionary means “on the near side of”.
Brian.
Comment by Brian Sheen — May 3, 2010 @ 4:09 am
Brian,
Cislunar means the volume of space between Earth and Moon. It derives by analogy from the Latin “Cisalpine Gaul” (i.e., Gaul before the Alps, or northern Italy) and “Transalpine Gaul” (Gaul beyond the Alps, or southern France).
Comment by Paul D. Spudis — May 3, 2010 @ 4:14 am
Dear Dr. Spudis,
you write that “significant quantities of water moving towards areas with lower mean surface temperatures and increasing in abundance with latitude” on the Moon.
I would like to ask if such areas of lower temperature could be made artificially. For example, could cold spots be produced by simply building big sunlight reflecting umbrella constructions?
If “the abundance of this surface water varies with time, being present in greater quantity in both local early morning and late evening and it increases in abundance with increasing latitude” then would this water molecules also move into those human-made cold traps and thus be gathered?
Comment by Hans-Peter Dollhopf — May 3, 2010 @ 7:14 am
Hans-Peter,
if such areas of lower temperature could be made artificially?
In principle, yes. But there are two problems. First, the temperatures would be lowered, but the diffuse thermal IR from surrounding, non-shaded areas would significantly raise the temperatures in the man-made trap. There is no way that cold on the order of the polar cold traps could be achieved. Second, even if we could make these artificial cold traps, the rates of water formation and deposition are so slow, we would never accumulate significant amounts of it. The polar cold traps have a lot of water because they have been there accumulating it for billions of years.
Comment by Paul D. Spudis — May 3, 2010 @ 7:39 am
As it seems to be the case that the Administration has nixed the Moon as a destination for *human* crews in the foreseeable future, we might consider how the Moon can become the domain of tele-operated robots. How much could be done without a single human hand on location? For example, might it be feasible to develop lunar water production tele-robotically and to then transport it, store it and crack it at an EML1 depot, all without a human hand touching it?
The future of robotics is tremendously exciting!
Comment by Itokawa — May 3, 2010 @ 8:56 am
What about ice being in caves on the Moon. Could there be ice in caves in equatorial regions?
If water migrates does follow any kind of route- would the lunar topography have any effect upon it’s movement.
If you were to measure the temperature say 10′ below the lunar regolith, would there be a significant difference between polar areas and equatorial?
Could it be that the geological formation under particular polar craters is a significant factor in determining whether the dark crater are cold enough to collect water?
Comment by gbaikie — May 3, 2010 @ 9:32 am
gbaikie,
Could there be ice in caves in equatorial regions?
Possibly. However, as we still don’t fully understand how the water is made/deposited and how it migrates, we cannot estimate the rate at which such water might accumulate in favorable, non-polar localities. My suspicion is that it will not accumulate as much water as the poles simply because the net flux of water available for capture is much less.
The temperature of the regolith below the diurnal layer (about the upper meter or so) is pretty constant at about 250 K, as measured at the Apollo 15 and 17 landing sites.
Comment by Paul D. Spudis — May 3, 2010 @ 10:10 am
Paul, do you have references for the escape vs diffusion rates of water molecules? I kinda sorta had the impression that escape requires photodissociation by solar UV with a half life of a few weeks, while brownian motion by ballistics hops of individual molecules (mean free path is hundreds of km?) delivers them to the polar cold traps within a few tens of hours. In that case, I’d expect most H2O molecules to be cold trapped before they can get nailed by a UV photon and broken up.
I don’t have easy access to an analysis, maybe you can track one down or do it yourself?
Comment by Doug Jones — May 3, 2010 @ 1:17 pm
Doug,
Many have modelled the transport and retention of water in the polar cold traps. I suggest the following references (all Journal of Geophysical Research):
J. Arnold (1979) JGR 84, 5659.
L Lanzerotti and W. Brown (1981) JGR 86, 3949.
R. Hodges (2002) JGR 107, 10.1029/2000JE001491
D. Crider and R. Vondrak (2003) JGR 108, 10.1029/2002JE002030
None of these studies (all based on impeccable physical analysis) predicted what has been directly observed on the Moon in the past few months. No moral drawn, but as an observational rather than theoretical scientist, I suspect that while what you are asking for can be calculated, those results would be of little value without confirming data from the real Moon.
Comment by Paul D. Spudis — May 3, 2010 @ 1:51 pm
The line “..Spectra from this impact event show evidence for other volatile substances, including ammonia and simple carbon compounds..” interested me. So estimates are that hydrocarbon slude (I.E. heavy crude oil by terstrial standards) is as common as water ni NEO comet cores. Could there be oil as well as water collecting at the poles?
Comment by Kelly Starks — May 3, 2010 @ 2:22 pm
Kelly,
So estimates are that hydrocarbon slude (I.E. heavy crude oil by terstrial standards) is as common as water ni NEO comet cores.
I didn’t mean to imply that the simple organics found in the LCROSS spectra are anywhere near as abundant as water. Things other than water are present in very minor amounts. In comets, water ice is about 95% of the total mass, with carbon dioxide being the next most abundant component. More complex organics are in the 1-2% range.
We’re still awaiting formal publication of the LCROSS results; I expect them to mirror cometary abundance, but we’ll just have to wait and see.
Comment by Paul D. Spudis — May 3, 2010 @ 3:09 pm
there is a fifth kind of water. the tears of lunar scientists once they heard of the current plan for human spaceflight.
Comment by Ben — May 3, 2010 @ 3:32 pm
Ok, and yes I suppose non NEO impacts would dominate the moon, and I’ve only heard of the NEO comet cores having that ratio.
Would certainly be useful though if rather then just finding water you could electralocize inly LOx/LH, you could actually find usable reserves of hydrocarbon fuel.
Comment by Kelly Starks — May 4, 2010 @ 10:32 am
I found some discussion of mean free paths and ballistic hops here- http://www.geoffreylandis.com/moonair.html
Comment by Doug Jones — May 4, 2010 @ 7:20 pm
“Ok, and yes I suppose non NEO impacts would dominate the moon, and I’ve only heard of the NEO comet cores having that ratio.”
NEO is Near Earth Object. Comet aren’t NEOs. Most NEO do have a high water content- if you consider say 10% of it’s total mass to be water. Some have as much as 25%. The ones with highest water content are thought that they could be dead comets. Water is very abundant in this universe. It is comprised of the most abundant [known] element- Hydrogen. Which is about 75% of total mass of the [known] universe.
Oxygen is also quite abundant- for example about 40% of the total mass of the surface of the Moon is oxygen. About the same goes for the Earth’s surface- and all other terrestrial planets or bodies in the solar system.
“Would certainly be useful though if rather then just finding water you could electralocize inly LOx/LH, you could actually find usable reserves of hydrocarbon fuel.”
Hydrocarbon fuel is useless as a fuel, if you don’t have oxidizer [such as Oxygen- O2]. Oxygen is highly reactive, and and unless you are on earth which has 20% of it’s atmosphere O2, you need to find some kind of oxidizer or or separate Oxygen from some compound with oxygen in it. Water is one such compound. And compared to other types of oxidized compounds it requires less energy- such as SiO2- Silicon Dioxide is a very common material found on the Moon or Earth- sand generally is mostly SiO2 as are most rocks. The next most abundance material other than Silicon Dioxide is Aluminum oxide:
Here’s a chart:
http://mistupid.com/geology/earthcrust.htm
To make aluminum it is also “split” using electricity:
“Because aluminum smelting involves passing an electric current through a molten electrolyte, it requires large amounts of electrical energy. On average, production of 2 lb (1 kg) of aluminum requires 15 kilowatt-hours (kWh) of energy. The cost of electricity represents about one-third of the cost of smelting aluminum.”
http://www.madehow.com/Volume-5/Aluminum.html
Water requires about a 1/3 of the amount electricity to make same amount of oxygen.
Oh, let me check that.
The atomic weight of Aluminum is 26.9
And oxygen is 15.9
So you get 2 oxygen for every Aluminum, so about 32 to 27
So you get more than 25% of mass as oxygen for every kg of Aluminum
So it only require about twice the amount energy rather 3 times as much as compared to water. Of course the aluminum might be useful for things- though so is the hydrogen useful for various things.
Comment by gbaikie — May 4, 2010 @ 9:15 pm
I propose an Operation Highjump initiative to emplace bases on the Moon, and commit to expanded scientific inquiry, which includes even the sortie missions to investigate a variety of landing sites. The outpost missions could be either intermittent or semi-permanent in nature: most bases in Antarctica are permanently staffed, but temporary forays to outlaying ground has always been part of the equation, thus, both types of expeditions will be needed for this effort. (Once base modules have been emplaced, sortie missions sent elsewhere would have back-up support, in the event of problems arising.) Yes, people, we SHOULD return to the Moon, first! We do NOT need a Book of World Records one-time stunt mission to an asteroid, now! Such a “farthest distance record” category spectacle will NOT lead to bases NOR resource utilization! Flexible Path is wholesale bunk & illusion!! Project Constellation could be America’s Operation Highjump quest for deep space. We deal with the Moon first, because it is the closest & easiest to reach. Remember that Lunar surface conditions are near-identical to the vacuum of interplanetary space. Keeping men alive there for ANY length of time, prepares us technologically for reaching any other far-deep space destination. Captain George Dufek, sir, we are ready to fly to the Pole!
Comment by Chris Castro — May 5, 2010 @ 1:10 am
1. >> “Ok, and yes I suppose non NEO impacts would dominate
2. >> the moon, and I’ve only heard of the NEO comet cores having that ratio.”
3.
4. Comment by gbaikie — May 4, 2010 @ 9:15 pm
> NEO is Near Earth Object. Comet aren’t NEOs. –
There are comet cores, or extinct comets that get stuck orbiting in NEO orbits. They boil off most of the volatiles and get down to rocky ores, water, and oil sludge – as you mentioned
>==. The ones with highest water content are thought that they could be dead comets.
>> “Would certainly be useful though if rather then just finding water
>> you could electralocize inly LOx/LH, you could actually find usable
>> reserves of hydrocarbon fuel.”
> Hydrocarbon fuel is useless as a fuel, if you don’t have oxidizer [such as Oxygen- O2]. ==
But a slight amount of hydrogen can be used to mine Oxygen out of the lunar soil. “burn” the soil with the hydrogen. Electralosize out the Ox from the resulting steam, reuse the hydrogen to recover more Oxygen.
Kerosene works much better in space ships then Hydrogen. Hydrogen works great ni rocket engines — not so good ni the overal launch vehicle.
Comment by Kelly Starks — May 5, 2010 @ 8:53 am
> Comment by Chris Castro — May 5, 2010 @ 1:10 am
> I propose an Operation Highjump initiative to emplace
> bases on the Moon, and commit to expanded scientific
> inquiry, which includes even the sortie missions to
> investigate a variety of landing sites. The outpost
> missions could be either intermittent or semi-permanent
> in nature: most bases in Antarctica are permanently
> staffed, ==
Now theres a return to the moon plan I cuold get excited by.
>== We do NOT need a Book of World Records one-time
> stunt mission to an asteroid, now! Such a “farthest
> distance record” category spectacle will NOT lead
> to bases NOR resource utilization! Flexible Path is
> wholesale bunk & illusion!! =
Oh hell yeah!
Comment by Kelly Starks — May 5, 2010 @ 8:57 am
“Kerosene works much better in space ships then Hydrogen. Hydrogen works great ni rocket engines — not so good ni the overal launch vehicle.”
I would agree that kerosene works better getting off earth than compared to hydrogen.
The reason is that kerosene is a denser fuel- more energy per gallon.
Getting off of Earth is a daunting task. Getting off the Moon isn’t.
So if you need a lot of power within a short period of time, kerosene is good stuff.
And also, suppose you needed a lot energy but could burn it for say 4 times the time as the time you need to get into earth orbit- say, 20 mins instead of 5 mins?
This means one doesn’t need as large of plumbing as you need for the Shuttle’s main engines but can deliver as much power. So if you need a lot of Delta-v, say to get to Mars fairly quick, you could use Hydrogen and it would work as well or better than Kerosene.
In other words burning at perigee of a highly elliptical orbit/escape trajectory one has more time than compared to trying reach orbit from earth surface.
Comment by gbaikie — May 7, 2010 @ 12:12 am
@ Kelly Starks….Hello, hello! Thanks for the vote of confidence! Are you with me? We popularize & liken Project Constellation as the Operation Highjump of our time. It was conceived as a daring American initiative to explore further & develop a previously visited frontier. Admirals Richard E. Byrd & George Dufek had no tolerance for the stupid “We’ve been there already” chorus line! You in fact, have to return to where you’ve been, in order to build bases & deal with resource utilization. You expand on the acheivements of past explorers, and augment the scope of the human presence on the previously visited territory. I suggest a new YouTube film-let, which blends in historical photos of the great Antarctic explorers of yesteryear, with the new paintings & animation depicting the Constellation Lunar expeditions. THIS IS HOW we should be selling the great idea! As the modern-day equivalent of Operation Highjump: which will accomplish on the Moon what that grand 1950′s initiative did in Antarctica, way back then! Let me know what you think, okay?
Comment by Chris Castro — May 7, 2010 @ 7:28 am
>>“Kerosene works much better in space ships then Hydrogen.
>> Hydrogen works great ni rocket engines — not so good in
>> the overal launch vehicle.”
> I would agree that kerosene works better getting off
> earth than compared to hydrogen.
> The reason is that kerosene is a denser fuel- more
> energy per gallon.
Actually the issue that worried me more is Hydron requires huge heavy tanks. So you craft has a higher dry weight needed for several times the weight of tanks, the fuel tends to boil off really easily, and for launch vehicles your drag on assent is much higher.
>==
> So if you need a lot of Delta-v, say to get to Mars
> fairly quick, you could use Hydrogen and it would work
> as well or better than Kerosene.
On a Mars trip the boil off issue becomes bigger for return fuel – but really, to get to Mars you need a fast nuclear powered ship, or a huge heavy moster with shielding and artificial gravity for round trip times of years.
Comment by Kelly Starks — May 7, 2010 @ 11:11 am
>Comment by Chris Castro — May 7, 2010 @ 7:28 am
>@ Kelly Starks….Hello, hello! Thanks for the vote
> of confidence! Are you with me? We popularize &
> liken Project Constellation as the Operation
> Highjump of our time. It was conceived as a daring
> American initiative to explore further & develop
> a previously visited frontier…
Certainly NOT the Constellation program currently dieing a slow death. That program could never do the:
> I propose an Operation Highjump initiative to emplace
> bases on the Moon, and commit to expanded scientific
> inquiry, which includes even the sortie missions to
> investigate a variety of landing sites. The outpost
> missions could be either intermittent or semi-permanent
> in nature: most bases in Antarctica are permanently
> staffed, ==
concept you want. Though the $100 billion Constellation aws budgeted for, you could built a new generation RLV with LEO to Low lunar orbit capacity (with on orbit refueling), and construct a base that looks more like a big arctic base (or a small version of the moonbase in 2001.).
Course that would assume yuo wanted to focus on building those things adn not politics as normal.
Comment by Kelly Starks — May 7, 2010 @ 11:25 am
@ Kelly Sparks…..Thanks for the reply on the blog. Project Constellation was grossly misunderstood by the space interest community! If Apollo was the dogsled trek to the South Pole, in terms of REACHING the Moon, then I fully liken Constellation to Operation Highjump that followed it a few decades later. Take a closer look at the Constellation elements: We’d get (a) a new heavy lift rocket, like the old Saturn 5: that new launcher is the Aries 5. [Again, Aries 1 will still be needed as a soley crew-launching rocket. The massive cargo being launched separately, is but a keenly thought-out safety measure, against a humongous rocket launch explosion, as had killed the Shuttle Challenger crew in 1986. Buzz Aldrin and others are wrong, when they denounce this part of the flight plan.] Aries 5 could launch base modules to the Moon, as well as later on to Mars. The surface habs that Robert Zubrin has in mind for the Red Planet, could have their genesis in the unmanned, automated landings of equipment & module craft, on the Moon (and/or Lunar orbit). Study closely, if you will, the possibilities that will come out of the Altair lunar lander getting built: An automated one-way variant could be developed. By not having to return up to Lunar orbit with a returning crew, the would-be ascent stage can now be used for soft-landing base modules & base equipment! Think about it! I for one, have long since seen the romance in Project Constellation. It WILL go beyond just merely reaching the Moon again. But the venture will inevitably START with sortie missions which are not much longer than far-past surface stays were, because (1) We will have to test out the viability of the landing craft, first. Indeed an Orion-Altair mission will have to be devoted to both an Apollo 9 & Apollo 10 type of flight plan at first. And (2) future select sortie missions will be needed to further scientifically analyze multiple landing sites, even after bases are established, with the base & base personnel able to back these expeditions up, with rescue, if needed. I am totally at peace with the fact that it will resemble Apollo at the begining. When the Antarctic was being further explored by a new generation, they arrived on the frozen continent in similar ways. But a great expansion of Lunar surface operations will be in store, once the United States has made the decision to go. I say we support Constellation, and lobby Congress into reviving the Project. Flexible Path NEVER intended to have a Lunar Return!!! The Moon was deceptively thrown in there as a weak “maybe-we’ll-still-do-that” tiny option, by the Augustine Commission; when all the while that commitee wanted to kill off any concept of a Lunar Return. If every destination now has to be 100% Virgin Territory, then bases & further scientific inquiry, and industrial development will NEVER happen, anyplace!! Tell me what you think, okay.
Comment by Chris Castro — May 8, 2010 @ 7:17 pm
“Actually the issue that worried me more is Hydrogen requires huge heavy tanks.”
“A balloon tank is a style of fuel tank used in the Atlas ICBM and Centaur upper stage that does not use an internal framework, but instead relies on a constant internal pressurization to keep its shape.”
http://en.wikipedia.org/wiki/Balloon_tank
“These so-called balloon tanks, with walls as thin as 0.030 inches, made possible the low mass
fractions of Altas booster and Centaur upper stage.”
http://books.google.com/books?id=ku3sBbICJGwC&lpg=PA97&ots=V-VeCBWJCs&dq=rocket%20%2B%20thickness%20balloon%20tanks&pg=PA93#v=onepage&q&f=false
So, instead of less then 1/32 of an inch, let’s look at 1/16th of a inch of steel and examine simple cylinders with flat ends.
A 2′ diameter and 10′ long cylinder with 1/16″ walls would be same as a 6.28318′ by 10′ or 62.8318 sq ft.
If the walls were an inch thick would be 62.8318 divided by 12 or 5.236 cubic feet of steel. Since it’s 1/16th of an inch it’s .327225 cubic feet of steel.
Each end has 3.14159 sq feet. So both ends is 6.28318 square feet and so .032725 cubic feet.
So the total is .36 cubic feet of steel. A cubic foot of steel weighs 495 lbs. So that tank weighs 178.2 lbs.
It has cubic volume of 31.4159 cubic feet
Kerosene weighs about 51 lbs per cubic foot
Liquid hydrogen weighs 4.4197 lbs per cubic foot
That tank filled with kerosene would have 1602.2 lbs of kerosene. Or 138.849 lbs of liquid hydrogen.
With this size tank, the tank weighs more than liquid hydrogen, and is just less than 1/9th weight of the kerosene.
Using same 1/16th steel with a 4′ diameter cylinder:
12.56636 times 10. 125.6636 square feet. And equal to .6545 cubic feet of steel. Plus the both ends being 25.133 square feet. Or 0.13 cubic feet. So total of .7854 cubic feet. Which weighs 388.773 lbs
It’s volume is 125.6636 cubic feet
So that’s 6408.8 lbs of kerosene
Or 555.39 lb of Liquid hydrogen
So with larger tank, the tank weighs around 1/16 of the mass of the Kerosene. And instead of the tank weighing more than hydrogen, the Liquid hydrogen is about 50% more than the weigh of the tank.
With rockets going into space rather 2 or 4 in diameter, it can be 12′ to 16′ in diameter [the external tank of shuttle is around 28' in diameter- for a good reason].
Repeat the above but with a 16′ diameter:
50.26544 times 10 gives 502.6544 sq feet
with ends being 402.123 sq feet. Total sq ft is 904.778
And is equal to 4.7123 cubic feet of steel. And weighs 2332.63 lbs.
The volume of it is 2010.6176 cubic ft.
The kerosene in it would weigh 102,541.5 lbs
Or the liquid hydrogen would weigh 8886.33 lbs
So large tanks are a significant advantage in term ratio of tank mass to fuel mass, particularly if one uses hydrogen. And larger tanks filled with hydrogen are also better if one wants to reduce boil off rate. You would more hydrogen boiling off in large tank, but the ratio to total amount of hydrogen would be considerable less
“So you craft has a higher dry weight needed for several times the weight of tanks, the fuel tends to boil off really easily, and for launch vehicles your drag on assent is much higher.”
When leaving earth’s surface to go into orbit, drag isn’t much of problem- in terms of losses to delta-v.
It’s more of problem of putting load on your structure- Q-max.
Though I conceded the hydrogen doesn’t work well for getting off earth.
And it mainly doesn’t work for getting off earth because it has lower thrust- it doesn’t deliver as much horsepower as kerosene can.
In the space environment and such places as the Moon or Mars you don’t need nearly as much horsepower as you do to leave earth.
The reason astronauts may have to experience 3 or 4 gees of acceleration is because lower acceleration has higher gravity losses.
Wiki says this:
“For example, to reach a speed of 7.8 km/s in low Earth orbit requires a delta-v of between 9 and 10 km/s. The additional 1.5 to 2 km/s delta-v is due to gravity losses and atmospheric drag.”
Well I would say only a little of that delta-v is lost to atmospheric drag, it’s mostly gravity losses or also called gravity drag.
The faster to can reach orbital speed the lower the gravity losses. If takes 300 second to reach orbital speed then it’s 300 second during which one has gravity losses [which are not constant rate during the flight profile].
If you hover a rocket for 300 seconds- the gravity loss would easy to figure out- it’s 300 times 9.8 or 2940 m/s.
It would require 2.94 km/sec of delta-v.
But if it takes a rocket 300 second to reach orbital speed the gravity losses are not 2.9 km/sec- rather it’s closer to about half that.
Most of the gravity losses *occur* at beginning of the launch and less occurs at the latter part of the launch and zero at orbital speed.
If you hover a rocket on the moon for 300 seconds the gravity losses would 300 times 1.6 or 480 m/s.
And lunar orbit speed is about 2 km/sec and escape being about 2.4 km/sec.
So, if you were to accelerate at 20 m/s it would take 100 seconds to reach lunar orbit.
So roughly 100 seconds times 1.6 and half that would be somewhere close to the gravity loss- around 60 m/s [.06 km/sec].
Suppose you had some cargo so fragile that it could not experience more than 1/2 of earth’s gravity. So you would need to accelerate at 4.9 – 1.6 m/s/s. A measly 3.3 m/s/s and so would require about 600 seconds to reach lunar orbit. That would mean your gravity loss would be about 480 m/s. Only about a 1/3 of the gravity loss from launching from earth.
Though, .48 km/sec is a significant faction to add to the normal 2.0 km/sec of delta-v to leave the moon- it’s almost 25% more to the delta-v. And it would similar to 25% increase to earth orbital velocity- around 8 times 1.25- so that’s 10 km/sec- comparatively it’s like the gravity loss of a shuttle launch.
But if one limited your cargo to only those that can survive such horrible load as they would experience sitting on some table on earth, the gravity loss will be small and therefore not require accelerations approaching 2 gee or higher.
Same goes very fast transits to Mars- one or maybe as much as two gee at earth perigee, should give enough delta-v.
Comment by gbaikie — May 9, 2010 @ 10:13 am
> @ Kelly Sparks…..
Kelly Starks
> Thanks for the reply on the blog.
>== Take a closer look at the Constellation elements:
> We’d get (a) a new heavy lift rocket, like the old
> Saturn 5: that new launcher is the Aries 5. [Again,
> Aries 1 will still be needed as a soley crew-launching
> rocket. The massive cargo being launched separately,
> is but a keenly thought-out safety measure, against
> a humongous rocket launch explosion, as had killed
> the Shuttle Challenger crew in 1986.==
You get a HLV, but no crew safty improvement — stats I was hearing was that it would likely have far higher fatality rates. (You misunderstood what killed the Challenger crew by the way – there was no explosion.)
The concept was not even to do this for the safty reasons you asume.
Ignoring that – its a STAGERINGlY expensive configuration capable of doing far less then the shuttle, which cost about 1/3rd as much to develop – and far cheaper per launch costs.
The Idea was Ares-V could fly 2 a year carrying 300 tons a year to orbit (though this varried wildly since various Ares-V concepts had cargo capacities from 75-200 tons.). As aposed to shuttle which generally lifted 150-200 tons a year at its flight rate. Course given you could ship the fuel up seperatly on smaller boosters, or fix the shuttles for far higher flight rates – and the full Constellation system was expendable, it wasn’t the big advange you seem to suggest.
>== Think about it! I for one, have long since seen the
> romance in Project Constellation. It WILL go beyond
> just merely reaching the Moon again.==
Its hard to see how? Its to inflexible and doesn’t have the lift capacity to do a decent Mars craft. For that you’d need to lift far more and assemble it in orbit, like Shuttle did with the ISS — but weer abandoning those concepts.
And of course nothing in Constellation is designed for long range deep space missions like Mars.
>== Flexible Path NEVER intended to have a Lunar Return!!!
If you mean Obama’s current proposals – true, they really arn’t intended to go past the space station.
Comment by Kelly Starks — May 9, 2010 @ 6:02 pm
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Pingback by Once Upon A Time In Heaven: Roundup | RedState — May 10, 2010 @ 1:46 pm
@ Kelly Starks….Hello. Its Chris Castro. Thanks for the analysis on my commentary. One thing: I always cringe when I hear this talk about NASA having to do MORE earth-orbital assembly work & further extravagant activity in LEO. To me, the light in my eyes flickers when a concept like Constellation emerges WHICH GETS US OUT OF LOW EARTH ORBIT. To me, the romance comes in our astronauts finally breaking orbit, and going off into the dark void. That moment when Apollo 8, in December of 1968, heard the directive:”You are go for TLI.” THAT equivalent moment alone, for OUR generation, will be the most historically amazing ever! Can you imagine, that fine day, when a crewed spacecraft heads off to go SOMEWHERE, for the first time in half a century! The name of the game, to me, is actually going someplace! So I get very leery & consterned of all this talk of: “Let’s not go anyplace now, until we’ve done more testing in LEO first.” It’s like an invitation for us to waste more decades trapped in LEO. (Obama’s Plan does a real good job at this. It keeps us marooned doing endless circles round the Earth for the next 15 or 20 years.) Look, Constellation does have that one earth-orbit rendezvous at the start of the space journey to contend with, true. But after that, it needs NO further LEO assembly work; and following that docking of those two spacecrafts, its earth-escape stage lights up, and the complement heads off to the Moon. This maneuver, can be replicated, with some variation, when the time comes to send unmanned modules & cargo craft over to the Red Planet. I say, that we support the Constellation effort, because it is the best & most realistic proposal, to get NASA out of LEO, and onto deep space—where the action REALLY should be.
Comment by Chris Castro — May 11, 2010 @ 2:56 am
> Chris Castro. Thanks for the analysis on my commentary.
No prob.
> One thing: I always cringe when I hear this talk about NASA having
> to do MORE earth-orbital assembly work & further extravagant activity
> in LEO. To me, the light in my eyes flickers when a concept like
> Constellation emerges WHICH GETS US OUT OF LOW EARTH ORBIT.
> To me, the romance comes in our astronauts finally breaking orbit, and
> going off into the dark void. ===
To me, I don’t care anymore if its just a stunt. If your just talking flags and footprints – I grew out of that 40 years ago. I want a sustainable space development program. Constellation is anathama to it. Griffens concept was to make space flight rare, expensive, and spectacular.
I want to see shuttle like craft building up craft the size of Discovery in 2001 that can go out to Mars or fartherout. Carry enough cargo to the moon to make bases that look like Anarctic base – mot like a ISS pod in the dirt with a LEM parked next to it.
>== I get very leery & consterned of all this talk of: “Let’s not go
> anyplace now, until we’ve done more testing in LEO first.” It’s like
> an invitation for us to waste more decades trapped in LEO. (Obama’s
> Plan does a real good job at this. It keeps us marooned doing endless
> circles round the Earth for the next 15 or 20 years.) ==
Hell Obama wants NASA tinkering in labs on Earth restudying really old technologies and calling it cutting edge. In the process its capacity to go out will be gone. All the hard won skills at building and working in space will be lost.
Constellation though doesn’t do any better. It just locks NASA into another dead end with hellishly high prices – and no capacity to do more. A giant leap backward from where we are now.
Comment by Kelly Starks — May 11, 2010 @ 8:26 pm
Comment by gbaikie — May 9, 2010 @ 10:13 am
>> “Actually the issue that worried me more is Hydrogen requires huge heavy tanks.”
> “A balloon tank is a style of fuel tank used in the Atlas ICBM and Centaur upper stage –
I know about Balloon tanks – though they have a mixed reputation. They tent to be very breakable, and lose all their stregth when they lose presure. Also they aren’t insulated which leads to boil off issues.
I’ll stick with lower cost, lighter, LOx/RP, systems.
>==
>> “So you craft has a higher dry weight needed for several times the
>> weight of tanks, the fuel tends to boil off really easily, and for launch
>> vehicles your drag on assent is much higher.”
> When leaving earth’s surface to go into orbit, drag isn’t much
> of problem- in terms of losses to delta-v.
More then you seem to think. Hell findings are its easier to build a Kerosene fueled SSTO then a Hydrogen fueled one. The lower drag lowers delta V – and the fuel lowers the dry weight fraction. And the fuels cheaper and easier to handle.
Comment by Kelly Starks — May 11, 2010 @ 8:46 pm
@ Kelly Starks….Hello. Thanks for the response. Too bad that you disagree with me on the good merits of Project Constellation. (We can cordially disagree, it’s okay.) But I see that we have common sentiment against Flexible Path/ Obama’s Space Plan. Even Robert Zubrin, that stalwart visionary of Mars expeditions & bases in OUR time, can see just how much the President’s plan reeks!! Check out the opening pages of the Mars Society website. I never thought that he would be a potential ally in the cause of overturning Obama’s Space Plan—that was very unexpected. He still has a negative view of NASA setting up Lunar Bases first, and he has continually in the past condemned renewed Lunar exploration, which I’ve always found abhorrent. I whole-heartedly believe that renewed Lunar flights & surface stays will be VERY necessary for the long-term good of making the human race a spacefaring one. We do NOT have to actually colonize the Moon. I move that we get started on the return mission enterprise, and that it lead to bases, and industrial development there. Antarctic-type of bases would be the advanced objective of Project Constellation, (or whatever other Return-To-The-Moon initiative is to take place). People like ourselves should try forging an alliance with those Mars enthusiasts who are NOT against conducting a Lunar Return, as an extensive imtermediate goal. The new Moon program could well be the Gemini project equivalent, which makes the Mars objective more realistic; much like what happened with Apollo.
Comment by Chris Castro — May 12, 2010 @ 7:41 pm
“The first loss is known as the gravity loss.
… For launch vehicles designed to launch payloads into low earth orbit ( LEO), initial T/W is in the order of 1.2 to 1.5 for liquid rockets and somewhat higher for solid rockets. Gravity losses are in the order of 2,000 to 4,000 fps (600 to 1,200 m/s) for a vertical trajectory to 100 km (328,000 ft).
Drag is another loss and is caused by friction between the launch vehicle and the atmosphere. Drag losses are in the order of about 500 fps (150 m/s) for medium sized launch vehicles such as the Delta or Atlas rockets for an earth to orbit trajectory. A long slender cylinder with a pointed nose is a favored shape to reduce drag losses since over three-quarter of drag losses are caused by supersonic drag.
…
Also drag losses are subjected to the “cubed-squared” law. As an object’s external dimensions increase, the surface area increases with the square of the dimension while the volume increases with the cube. Since drag is a function of surface area and not volume, then increasing the launch vehicle size will reduce drag losses. For example, the huge Saturn V moon rocket had drag losses of only 130 fps (40 m/s).
…
Steering loss is the last major loss and is caused by the need to steer the launch vehicle.
…
In order to get an appreciation for steering losses, the Delta II rocket has only 110 fps (34 m/s) of steering losses as compared to the Space Shuttle’s 1,200 fps (365 m/s), both for a low earth orbit trajectory.”
http://www.spacefuture.com/archive/flight_mechanics_of_manned_suborbital_reusable_launch_vehicles_with_recommendations_for_launch_and_recovery.shtml
It would seem that in regard to the Shuttle, steering losses are as much or more than it’s losses from atmospheric drag. And the shuttle is not sleek design in regard to atmospheric drag.
So with rockets that leave the earth’s surface to go into space, gravity losses are going to be one the most dominate factors.
And atmospheric drag is mostly significant because the loads it puts on the structure of the rocket. This is referred to as max Q.
“In aerospace engineering, max Q is the point of maximum dynamic pressure, the point at which aerodynamic stress on a spacecraft in atmospheric flight is maximized.
Therefore, there will necessarily be a point where the dynamic pressure is maximum: that point is precisely max Q.
…
In other words, below the max Q point, the effect of the spacecraft acceleration overcomes the decrease in density as to create more dynamic pressure (opposing kinetic energy) acting on the craft. Above the max Q point, the opposite is true, and the dynamic pressure acting against the craft decreases as the air density decreases, ultimately reaching a Q of 0 where the air density is zero.
Rockets, aircraft, missiles, and other vehicles are all designed to withstand only a certain maximum q before they will suffer structural damage, so the term is used throughout aerospace engineering and not just by NASA.
During a normal Space Shuttle launch, for example, max Q is at an altitude of around 11 km (35,000 ft).”
http://en.wikipedia.org/wiki/Max_Q
Comment by gbaikie — May 12, 2010 @ 11:23 pm
Hi chris
>== I see that we have common sentiment against Flexible
> Path/ Obama’s Space Plan. ==
Yeah when you get so flexible yuo can do anything – or nothing – and say your still on the path. ..Which seems to be the plan.
Some measurable milesstones would be good!
>== Even Robert Zubrin, that stalwart visionary of Mars
> expeditions & bases in OUR time, can see just how much
> the President’s plan reeks!! ==
Yeah I heard him riping into it in a episode of Dave Livingstons “the space Show” a week or two back. Zubrin had a good point about VASMIR being inefficent adn to complex — but having good old boy support from other fellow astrounauts.
>== I never thought that he would be a potential ally
> in the cause of overturning Obama’s Space Plan—that
> was very unexpected. ==
Not really that surprizing. Going to the Moon and then preparing for Mars later he thought was inefficent, but you were talking seriously about going to Mars. Doing nothing and not even thinking about Mars, or developing anything for Mars — and then making a big show of reresearching prep Apolo Technologies?! That would naturally raise red flags with Zubrin.
I think Obama really misscalculaetd how many voices would not roll over on this – and how many in congress wuold agree with them, not Obama about effectivly shutting down NASA.
>== [Zubrin]has continually in the past condemned renewed
> Lunar exploration, which I’ve always found abhorrent. ==
Agreed. Its like sending a dozen guys to Austraila a cuople days adn say you exustivly studied it. Obamas brushing off returning to the moon with a “We’ve been there, adn its not worth going back again” is stuningly dumb.
A couple bases teh size of Antarctic bases would be good.
..And its a good place to test radition resistent designs and equipment.
>== Antarctic-type of bases would be the advanced
> objective of Project Constellation, ==
Not realy. Tey weer just looking at a space station like pod you could visit intermitently.
Way to little for now a days.
Comment by Kelly Starks — May 13, 2010 @ 11:15 am
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