Author Topic: Exploration Alternatives: From Propellant Depots to Commercial Lunar Base  (Read 41737 times)

Offline muomega0

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....

I'd expect the NEO mission to be quietly de-emphasised.


The ISS would be an affordable and useful place to test radiation protection technologies.



IOW: a return to the Constellation mission sets......


The ISS is in a magnetic field, why would the ISS be affordable and useful for testing GCR protection?

As stated many times, the lunar push to develop ISRU production of 1000 mT/year and new engine development will proceed, and other technology development for beyond lunar operations "will be be quietly de-emphasised"    sic  The old bait and switch.   Authorized and not appropriated.

Quote from: Robotbeat
    ..a lightweight GCR shield system ...


A contradiction in terms.

must add.......Given that zero dollars is spent on development...  If you do not study it......Authorized and not Appropriated.

Constellation boiled away 70 mT of propellant for a Mars mission without including GCR protection the architecture and GCR protection is half or less this mass.....not such a well thought out strategy?  EP is looking better and better...oops...forgot about the quietly dismissed part ;)

You guys make be laugh!   ;D

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“The more that you read, the more things you will know. The more that you learn, the more places you'll go.”

Offline HappyMartian

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...


The ISS is in a magnetic field, why would the ISS be affordable and useful for testing GCR protection?
...

"Of the above factors, all but the first one apply to low earth orbit craft, such as the Space Shuttle and the International Space Station. Exposures on the ISS average 150 mSv per year, although frequent crew rotations minimize individual risk.[11] Astronauts on Apollo and Skylab missions received on average 1.2 mSv/day and 1.4 mSv/day respectively.[11] Since the durations of the Apollo and Skylab missions were days and months, respectively, rather than years, the doses involved were smaller than would be expected on future long-term missions such as to a near-Earth asteroid or to Mars (unless far more shielding could be provided)."

And, "The Mars Radiation Environment Experiment (MARIE) was launched in 2001 in order to collect more data. Estimates are that humans unshielded in interplanetary space would receive annually roughly 400 to 900 milliSieverts (mSv) (compared to 2.4 mSv on Earth) and that a Mars mission (12 months in flight and 18 months on Mars) might expose shielded astronauts to ~500 to 1000 mSv.[16] These doses approach the 1 to 4 Sv career limits advised by the National Council on Radiation Protection and Measurements for Low Earth orbit activities."

From: Health threat from cosmic rays
At: http://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays
"The Moon is the most accessible destination for realizing commercial, exploration and scientific objectives beyond low Earth orbit." - LEAG

Offline Robotbeat

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And if shielded with some modest amount of shielding, the dose will be far less. ISS levels are possible using liquid hydrogen shielding. With plastic shielding, ISS levels are possible if going durin solar max.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline JohnFornaro

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Plus, to the OP and all:  Don't forget that Shackelton Energy has been working this problem for over a year, and that they have some talent and connections as well.
Sometimes I just flat out don't get it.

Offline kkattula

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... 
Recall that at most lunar sorties are 120 mT, so 2X year is 240 mT. 
...

120 mT is pretty small, something like 85% of it will be propellant. Remember that the massive Saturn V was needed just to send a small 3 man capsule and 2 man lander to the moon.

And Mars is going to need 400 to 500 tons of propellant per mission.

The best use for SLS may be as a propellant/EDS launcher.  Let the smaller LVs launch the more compact expensive hardware.

Still, higher launch rate for SLS is very important. It should launch 5 to 10 times per year. Not this once every 6 months rubbish.


Offline HappyMartian

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And if shielded with some modest amount of shielding, the dose will be far less. ISS levels are possible using liquid hydrogen shielding. With plastic shielding, ISS levels are possible if going durin solar max.


Please carefully define "shielded with some modest amount of shielding", because that doesn't seem to be the case.


Cheers!
"The Moon is the most accessible destination for realizing commercial, exploration and scientific objectives beyond low Earth orbit." - LEAG

Offline Robotbeat

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And if shielded with some modest amount of shielding, the dose will be far less. ISS levels are possible using liquid hydrogen shielding. With plastic shielding, ISS levels are possible if going durin solar max.


Please carefully define "shielded with some modest amount of shielding", because that doesn't seem to be the case.


Cheers!
300kg per m^2 (which is about 16mT for a small Destiny-sized module, which isn't unreasonable for a Mars Transfer Vehicle) of hydrogen would get dose equivalent of about 100mSv/year even during solar minimum (which has twice as much GCR), which is less than ISS. ... Actually, even just 8mT of hydrogen would be enough for ISS levels. (This is compared to the ~5mT of hydrogen already going to be launched for the Delta IV Heavy upper stage and block 1 CPS for SLS... 5mT should be enough during solar max).

Higher amounts of plastic shielding (say, 600kg/m^2, 32mT for a MTV) should be about enough to make the dose equivalent to ISS at solar max.
« Last Edit: 11/16/2012 04:10 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline MP99

There is no Obama policy concerning a return to the moon, commercial or otherwise. The Commercial Crew program is geared toward access to the ISS. That's it.

ISTM more accurate to say they initiated a Commercial Crew programme in hopes that third parties would come along and share costs.

While that might have been anticipated as being usage in LEO, it seems this proposal might leverage it for BLEO.

cheers, Martin

Offline Robotbeat

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There is no Obama policy concerning a return to the moon, commercial or otherwise. The Commercial Crew program is geared toward access to the ISS. That's it.

ISTM more accurate to say they initiated a Commercial Crew programme in hopes that third parties would come along and share costs.

While that might have been anticipated as being usage in LEO, it seems this proposal might leverage it for BLEO.

cheers, Martin
Precisely.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline muomega0

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... 
Recall that at most lunar sorties are 120 mT, so 2X year is 240 mT. 
...

120 mT is pretty small, something like 85% of it will be propellant. Remember that the massive Saturn V was needed just to send a small 3 man capsule and 2 man lander to the moon.

And Mars is going to need 400 to 500 tons of propellant per mission.

The best use for SLS may be as a propellant/EDS launcher.  Let the smaller LVs launch the more compact expensive hardware.

Still, higher launch rate for SLS is very important. It should launch 5 to 10 times per year. Not this once every 6 months rubbish.

Lol.

First, the Mars DRM mission did not include any GCR mitigation mass in the studies.  oops?!

Mars is every two years.   So assuming MARS DRM 5, 450/2 = 250 mT/year.    If stored in a ZBO facility that also uses zero propellant for attitude control, unlike the ULA transfer stages with sunshields, then the whole mission is easily staged with ZBO depots and the existing smaller fleet at significantly less cost than SLS.

It gets better.  Without GCR protection, one cannot head to Mars.

Compare the mass to head to Mars with hydrogen or poly shielding versus active systems.....active wins hands down.

It gets even better:  depots, GRC protection, and ISRU all need lightweight cryocoolers--common hardware elements for sustainability.

HLV/Depot Architecture:  Oxymoron

The L2 Gateway in essences provides a long term critical science goal to economically develop GCR protection strategies, increases flight rates, and provides guaranteed spinoffs back to earth with the flexible option of proceeding with other missions and technology challenges once solutions are found and demonstrated.  It is most certainly not a destination, only a critical stepping stone.

Offline Robotbeat

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.
It gets better.  Without GCR protection, one cannot head to Mars.
...
False. See, this is the sort of extreme position about the level of risk faced that I was talking about. GCR represents an increase in cancer levels. Maybe. But not more than smoking. If the risk is no more than smoking, then of course you could head to Mars without GCR protection.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Robotbeat

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Additionally, a magic active shielding system would be incredibly complicated and it is not even clear it would be less massive than, say, liquid hydrogen shielding.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Lobo

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Could this be a bunch of right-wing billionaires trying to make a political statement?

Billionares, right-wing or left-wing (and there are a LOT of left wing billionaires), didn't get to be billionaires by fritting away their money uselessly.

Musk is a pretty liberal billionaire, but he saw a business model that could work when he founded SpaceX.  Part of that busness model was that NASA would invest in them as well, but he wasn't fritting away money on some wild pipe dream or political statement.

So, the answer to your question is, "no".

Offline Lobo

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Obama reinforced the direction of encouraging the private sector development of space. The Obama Administration hitched their wagon to so-called "commercial space," and if commercial space actually succeeds in doing this (I'm skeptical, though it'd be cool), it would be, again, a vindication of that decision.

Ironic that he hitches his wagon to the private sector in the area of space, but refuseds to in any other area, and mocks those who advocate it.  (healthcare, education, energy, etc.)

Mr. President...if it is a good idea in space...maybe it's a good idea other places too?..
Just sayin...


Offline Lobo

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If using US hardware, the only viable launch vehicle in terms of cost is the Falcon Heavy (FH). Two of these can do a Lunar mission, but you need a hydrolox Earth escape stage. Three FH (crewed vehicle/lander, Earth escape stage and refueling mission) using kerolox or methanelox to refuel the Earth escape stage could also be used. Dragon is already designed for beyond LEO missions. It just needs deep space communications and a storable stage for Lunar orbit insertion and trans Earth injection (TEI). An Apollo type Lunar Module using storable propellants would need to be developed. Alternatively, a kerolox or methanelox crasher stage can perform Lunar orbit insertion and 75% of Lunar descent, for a greater payload capability.

So who are the customers? Probably most likely NASA as rich tourists have a hard time even getting to orbit (the last space tourist was in 2009). I don't think Elon Musk is interested in this, as he's mostly interested in Mars. However, I'm sure he'll be happy to sell FH's and Dragons to someone wanting to go to the Moon.

Well said Steve,

ULA could do it too with D4H.  A D4H with GEM-60’s and a new upper stage could get payloads into the 40-50mt range.  With crossfeed and RS-68B it can get to about a crossfed FH. 
ULA, however, brings with it massive legacy and overhead, so it’s hard to say if they could be competitive compared to FH.  Maybe they could change their business plan to be competitive?  Dunno.  D4H derivatives would be all US made, and could launch from LC-37 with some minor pad mods.

Either FH or D4H, a new hydrolox US will be needed, so that’s common to either.  Unless SpaceX wants to get into that business and develop it, I’m not sure who else would be in that game other than ULA (or I suppose either LM or Boeing could do it as a non-ULA individual entity, they developed DCSS and Centaur themselves before the merger).  So ULA/Boeing/LM would probably be part of this at some level.  Maybe they’d agree to develop ACES as part of this with an agreement for it to fly on FH for missions for this consortium?

But, assuming for a moment FH would be the LV of choice, they could do a 2-FH launch scenario like you said, or even a 3 launch scenario, with F9 v.1.1 launching Dragon with a service module, if they can get the mass of a Dragon CSM down enough to fly on the F9 v1.1.  That would free up mass on the FH’s, and it can be wheeled out of the F9 hanger at LC-40 for a launch once the first two FH’s had successfully launched their payloads for a successful rendezvous in LEO.  And that can keep the crew launch it’s own thing launching on a system that would potentially already be flying astronauts up to the ISS (maybe). 
A BLEO Dragon CSM could maybe us a superDraco engine as it’s SMME, as the superDraco will deep throttle and multiple restart capability. 

Offline HappyMartian

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"Galactic Cosmic Rays and Solar Particle Events
SPE
Extremely high particle flux and radiation dose rate, however,
“Soft” kinetic energy spectra – 0.1 to >103 MeV/Nucleon – so shielding materials can be effective at reasonable thickness/mass
Short duration – a few days at most – storm shelter concept – reduces vehicle weight
So, this isn’t the real problem
GCR
Relatively low particle flux and radiation dose rate, however,
'Extremely hard' kinetic energy spectra - 10 to > 106 MeV/Nucleon - shielding with materials is relatively ineffective at reasonable thicknesses/mass
Continuously present (some solar cycle modulations), so dose accumulates during the entire mission
Considerable uncertainty in evaluating human health risks (nothing like GCR in our natural environment)
This is the real problem!"

From: Designing Spacecraft and Mission Operations Plans to Meet Flight Crew Radiation Dose Requirements: Why is this an “Epic Challenge” for Long-Term Manned Interplanetary Flight (Hint – It’s About the Money)  By Steve Koontz   NASA/MIT Workshop    06/26/12
At: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120012405_2012011633.pdf



"Potential early and late effects on the central nervous system are of great concern to NASA and an area of active current research interest. Both short and long term effects of CNS exposure to galactic cosmic radiation (GCR) are likely to pose significant neurological health risks to human long-term space travel.[17][18]"

"Estimates suggest considerable exposure to high energy heavy (HZE) ions as well as protons and secondary radiations during Mars or prolonged Lunar missions with estimates of whole body effective dose ranging from 0.17 to greater than 1.0 Sv.[19] Given the high linear energy transfer (LET) potential of such particles, a considerable proportion of those cells exposed to HZE radiation are likely to die. Based on calculations of heavy ion fluences during space flight as well as various experimental cell models, as many as 5% of an astronaut’s cells might be killed during such missions.[20][21] With respect to cells in critical brain regions, as many as 13% of such cells may be traversed at least once by an iron ion during a three year Mars mission.[22]"

"By one NASA estimate, for each year that astronauts spend in deep space, about one-third of their DNA will be hit directly by heavy ions.[23] Thus, loss of critical cells in highly complex and organized functional structures like the central nervous system (CNS) could result in compromised astronaut function, such as changes in sensory perception, proprioception, and behavior[24] or longer term decrements in cognitive and behavioral functions, including accelerated onset or progression of degenerative brain disease(s)."

From: Health threat from cosmic rays
At: http://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays



Private entities or other countries can envision going to the Moon, and they can plan to do it without adding to their Lunar mission risks the additional risks and high costs of the odd requirement of first going to L2. NASA has to plan on building an unneeded, complexity adding, and risky L2 space station, simply because the President has loudly proclaimed that he doesn't want NASA astronauts going to the Moon.

After the L2 space station is built, perhaps the President will allow NASA to do a few token missions to the Lunar surface, or maybe not. An entrenched anti-moon policy may become the new norm for NASA.

Spending scarce tax payer money on planning for a needed Altair or other human Lunar Lander is not allowed by the President. Spending scarce tax payer money on planning for an unneeded, costly, and complexity adding L2 space station should be considered sensible and wise by Congress, shouldn't it? 

The President's anti-moon thinking is fully capable of wasting billions of scarce taxpayer dollars on a dead end L2 space station that we cannot afford to properly shield from radiation and cannot afford to regularly use for asteroid or Mars missions because of the high cost of hauling from Earth the massive shielding that is needed for such deep space vehicles.

Alice in Wonderland could have devised a much wiser space exploration plan than what is currently coming from the President.
"The Moon is the most accessible destination for realizing commercial, exploration and scientific objectives beyond low Earth orbit." - LEAG

Offline Jim

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More nonsense from HM.  Let it go.  You are in the wrong.

Offline HappyMartian

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More nonsense from HM.  Let it go.  You are in the wrong.

Jim, instead of just attacking, please state what you think we should be doing for the next twenty years.
 
Do you support the President's policy of no astronauts on the Moon?

Do you support the President's L2 space station?

Many folks have put ideas on the discussion table.

However, you don't offer real world alternatives that are affordable, logical, and clearly supported by Congress to implement NASA's legal mission of beyond low Earth orbit human space exploration.


 :)
"The Moon is the most accessible destination for realizing commercial, exploration and scientific objectives beyond low Earth orbit." - LEAG

Offline GREverett

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"I don't like their idea of starting off with a two man lander. I would like to hear what they think of the t/Space CEV concept? As I believe it would work well with fuel depot/transfer,  Lagrange points, and be able to land more than two crew at a time, plus it was to be reusable."

I don't think they would go to the expense of building a t/Space CEV. Why not rip the heat shield off a dragon and otherwise weight reduce it. Then ad some more fuel. Make a nice little two person LEM Lego style development.


Offline Warren Platts

"I don't like their idea of starting off with a two man lander. I would like to hear what they think of the t/Space CEV concept? As I believe it would work well with fuel depot/transfer,  Lagrange points, and be able to land more than two crew at a time, plus it was to be reusable."

I don't think they would go to the expense of building a t/Space CEV. Why not rip the heat shield off a dragon and otherwise weight reduce it. Then ad some more fuel. Make a nice little two person LEM Lego style development.

The problem is time. They want to get to the Moon by 2020. Within 50 years of the Apollo landings. That's going to be tough, no matter what.

Looks like China's robot is going to beat all GLXP competitors. Indeed, it's quite likely that none of the commercial competitors will reach the Moon before the contest expires entirely. So they definitely got their work cut out for them, even with a shoestring, 2-man lander....
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

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