Author Topic: How to revive the Constellation Program - reduce the cost with a Lunar Elevator  (Read 10560 times)

Offline cfrjlr

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The NASA Constellation Program was cancelled when the price tag estimates reached $100 Billion. This is inevitable if one is trying to land lots of heavy payloads on to the Moon and bring them back using chemical rockets. A lunar elevator can be built today cheaply using widely available inexpensive commercial super-strong materials, such as M5, Zylon or Dyneema. A lunar elevator reduces the cost of soft landing by a factor of sixfold, and reduces sample return by one thousand times. A lunar elevator with a payload capability of 100 kg can be built for less than $1 Billion. This could reduce the cost of a Constellation effort from $100 Billion [way unaffordable] down to $20 B which would be easily affordable within the NASA budget.

For soft landing payloads, the LSE pays for itself in 20 payload cycles; for sample return it can pay for itself in as little as a single payload cycle, depending on the sample site.

The lunar elevator concept is a long tether which is loaded under tension by terrestrial and lunar gravity. One end is anchored on the Moon and the other end free, hanging towards Earth. The orbital center of mass of the system is located at an Earth-Moon Lagrange location, either L1 or L2, approximately 50,000 kilometres from the lunar surface. Such a tether can now be built inexpensively from commercially available materials, e.g. Zylon, Dyneema, M5. The near-side L1 tether is attached to the lunar equator at Sinus Medii.

For a one time capital cost of US$800 Million [2012], a lunar elevator can be built today using existing available materials. This first generation lunar elevator will softly deliver an infinite number of payloads to the lunar surface, each weighing 100 kg, and retrieve the same amount of material from the lunar surface. The alternative of using chemical rockets to soft land on the Moon [or return material] is prohibitively expensive.

The first generation lunar elevator kit weighs 30 tons and can be delivered today to the Lunar L1 lagrange libration location, using a single Delta-IV (or Ariane-V) launch. From there the tether is unreeled upwards and downwards. The lower end anchors itself into the lunar soil using robotic penetrators.

The lunar elevator represents a game changing technology which will open up the Moon to commercial mining and long term human exploration.

Background:

A very nice lunar elevator study report from Israel. Student Project at The Technion, Israel, 2008. A full year under the supervision of Dr Alexander Kogan.
Conclusions
• Cargo delivery from the Moon to the Earth can be done within 6 days using solar power and no propellant.
• The cargo system uses a cable car moving along a stretched ribbon.
• The ribbon is kept stretched by terrestrial and lunar gravity. One end is anchored on the Moon and the other one free.
• The cargo released from the cable car performs a passive flight to the Earth.

Here is the link to the details:

http://lunarjacobsladder.webs.com/Jacobs%20Ladder%20IACAS%202010.pdf

more details here too ... http://asri.technion.ac.il/jacobs-ladder/

The Earth's Moon is a treasure trove of mineral resources, such as precious metals, rare earth elements, Helium-3 and Oxygen for propellants. However, the cost of soft landing on the Moon is currently very high. A lunar elevator can bring the cost of lunar mining to a par with terrestrial mining for some commodities.

The first market will probably be Helium-3 which currently sells on the terrestrial market for one million dollars per ounce. There is a critical shortage of He-3 which is in great demand for various industrial applications. Terrestrial supplies of He-3 will be exhausted by 2030. He-3 is abundant on the lunar surface.

The lunar elevator can also transport oxygen from the Moon to Low Earth Orbit where it can refuel tugs to take satellites from LEO to GEO, a significant revenue source. This reduces the cost of launches to GEO by a factor of 7.

Offline aero

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Ok - If we had a Lunar elevator all packaged up and ready to go, it would make a nice payload for the Falcon Heavy demo flight. If the FH can loft 30 tons to L1. Is that 60,000 pounds or 30,000 kg?
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Offline Jim

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For a one time capital cost of US$800 Million [2012],

Unsubstantiated claim.   There is no realistic basis for that number.

Offline IRobot

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The first generation lunar elevator kit weighs 30 tons and can be delivered today to the Lunar L1 lagrange libration location, using a single Delta-IV (or Ariane-V) launch.
30 tons to L1 in a single Delta IV or Ariane V? Was that a typo?

Offline cfrjlr

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oops yes, originally we were looking at 11 tons.

30 tons would be at least two launches.

Thanks,

CFR.

Offline IRobot

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• Cargo delivery from the Moon to the Earth can be done within 6 days using solar power and no propellant.
Another typo? Or are you thinking of solar sails?

Offline cfrjlr

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The statement is correct as written.

The climber is solar powered, electric motors pull the climber up and down the tether, wheels interacting with the ribbon via friction.

The cruising speed is 700 metres per second, which results in a travel time of 6 to 7 days.


Offline dror

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From the report:
"Tether: length 325,000 km, mass 245ton, end mass 16ton, material M5 fiber"
Yet there is no description of what  the 30ton first generation kit contains.
???
Space is hard immensely complex and high risk !

Offline cfrjlr

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The 30 ton version was developed by LiftPort.   The 250 ton version was developed by Tehcnion.  Different groups working independently.  I can get you a breakdown for the 30 ton LiftPort system if you like, it is in a PDF file which I ill attach later.

LiftPort and Technion were completely unaware of each other  until  a  few  months ago ... so the results and analysis are completely independent, and interesting that e are entirely consistent.

Offline cfrjlr

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OK at LiftPort Group we have not developed a climber weight breakdown for the 30 ton version in the same level of detail as the Technion group did for their 260 ton version.   Attached to this message is a PDF file
  [ LEAG_2013_tme.pdf ]  with a 49 ton LiftPort version which describes both a nearside version and a far side version, which you might find interesting.

Offline IRobot

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The statement is correct as written.

The climber is solar powered, electric motors pull the climber up and down the tether, wheels interacting with the ribbon via friction.

The cruising speed is 700 metres per second, which results in a travel time of 6 to 7 days.
No it is not, you said "from the Moon to the Earth" and then you talked about moon to end of tether.

Offline cfrjlr

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I am sorry you lost me, the comments you make appear unrelated to the sections of text you are quoting.

I really do not understand your question.



Offline aero

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Lunar elevator discussions generally speculate that the anchor point on the moon will be at 0,0 lat, long, but occasionally a proposal points out that the anchor point could be elsewhere on the moon.

Question: Could the tether/cable be anchored to a network of guy lines with a switching junction at say 50 km lunar altitude so that the guy lines could be used for cable cars to move between guy line anchors (activity centers)? If so, then a lunar cable car network could be constructed without the need to build expensive towers.
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Offline Jim

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The 30 ton version was developed by LiftPort.   The 250 ton version was developed by Tehcnion. 


You are missing the term "concept" in both sentences.  No hardware exists, so neither was "developed"
« Last Edit: 02/18/2014 07:43 pm by Jim »

Offline cfrjlr

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yes, thank you for that important clarification, readers might have been greatly confused.
.

Offline Mark S

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I am sorry you lost me, the comments you make appear unrelated to the sections of text you are quoting.

I really do not understand your question.

How does the cargo, after a six-day trip from the lunar surface to the upper end of the tether, get from the tether back to Earth? Passive flight? You mean you just turn it loose and it floats back to Earth

You should correct your initial statement to replace "Earth" to "top of tether".

Thanks.

Conclusions
• Cargo delivery from the Moon to the Earth top of the tether can be done within 6 days using solar power and no propellant.
• The cargo system uses a cable car moving along a stretched ribbon.
• The ribbon is kept stretched by terrestrial and lunar gravity. One end is anchored on the Moon and the other one free.
• The cargo released from the cable car performs a passive flight to the Earth.


Can you describe this "passive flight"? What mechanism is used to slow the cargo's speed enough to get its orbit to intersect the Earth? Wouldn't the cargo just go into an elongated orbit otherwise? How long does the passive flight take? Is there a mechanism on the other end to capture the payloads? If a payload is missed on the receiving end, will it impact the Earth?

Thanks.

Offline IRobot

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• Cargo delivery from the Moon to the Earth can be done within 6 days using solar power and no propellant.
Another typo? Or are you thinking of solar sails?

Ok, I'm requoting it again. Your post talks about Moon-Earth travel without propellant. Don't you mean Moon-end of tether using the elevator? Moon-Earth travel will of course require propellant, except if you use a solar sail, which I   seriously doubt it was on your mind.
« Last Edit: 02/18/2014 09:42 pm by IRobot »

Offline Hop_David

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I am sorry you lost me, the comments you make appear unrelated to the sections of text you are quoting.

I really do not understand your question.

How does the cargo, after a six-day trip from the lunar surface to the upper end of the tether, get from the tether back to Earth? Passive flight? You mean you just turn it loose and it floats back to Earth

You should correct your initial statement to replace "Earth" to "top of tether".

Thanks.

Here's a pic of a lunar elevator from Beanstalks, Elvators, Clarke Towers:



Dropping from the point 160,000 km below EML1 would send a payload to an earth atmosphere grazing orbit. This point is 216,300 km from the moon's surface. Charles had said a climber's speed would be .7 km/s,  216,300/(.7km/s) is 30900 309000 seconds or about 3.6 days.

The apogee of that trans-earth orbit is about 160,000 km altitude. The period of a  300 km x 160,000 altitude orbit is about 3 days and the trip from tether to perigee is about half that. That's 1.5 days.

3.6 + 1.5 = 5.1. So if they could manage a climber that averages .7 km/s, moon surface to earth atmosphere grazing perigee would be about 5 days.

Edit: corrected typo that Aero pointed out.
« Last Edit: 02/18/2014 11:03 pm by Hop_David »

Offline aero

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Yea - you dropped a decimal there, it's 309,000 seconds but still about 3.6 days.
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Offline A_M_Swallow

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{snip}
The first market will probably be Helium-3 which currently sells on the terrestrial market for one million dollars per ounce. There is a critical shortage of He-3 which is in great demand for various industrial applications. Terrestrial supplies of He-3 will be exhausted by 2030. He-3 is abundant on the lunar surface.

{snip}

Not that old wild goose chase.  Forget He-3.  It makes you look like a crank.

Offline A_M_Swallow

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Ok, I'm requoting it again. Your post talks about Moon-Earth travel without propellant. Don't you mean Moon-end of tether using the elevator? Moon-Earth travel will of course require propellant, except if you use a solar sail, which I   seriously doubt it was on your mind.

The Moon is in Earth orbit so things released from a lunar elevator will be pulled towards the Earth.

An RCS will be needed to guide the payload.  With a maximum mass of 100 kg the RCS can be small.

Offline Hop_David

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{snip}
The first market will probably be Helium-3 which currently sells on the terrestrial market for one million dollars per ounce. There is a critical shortage of He-3 which is in great demand for various industrial applications. Terrestrial supplies of He-3 will be exhausted by 2030. He-3 is abundant on the lunar surface.

{snip}

Not that old wild goose chase.  Forget He-3.  It makes you look like a crank.

Not necessarily. Charles describes existing markets for He-3, not speculative use in nonexistent fusion reactors.

Yes, it's a long shot. But not as cranky as Harrison Schmitt's scheme.

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