Avoiding Lunar Lander Sandblasting

[grb3]

After reading the article "How Lunar Landers Sandblasted the Moon" on Space.com, does it make sense for a moon version of a space elevator? If there is enough force to keep the "line" extended straight with sufficient length, the negative aspects of "sandblasting" could be eliminated. Of course, it (a space elevator) would likely have to be attached around the moon's equator on the side of the moon we don't see. What would the distance be between the equator and the Moon's South Pole?

 

[usn_skwerl]

2,730 km/1696 miles or so between the equator and the poles.<br />http://www.universetoday.com/2004/11/18/space-elevator-build-it-on-the-moon-first/<br /><blockquote><font class="small">In reply to:</font><hr /><p>On the Moon, the force of gravity is one sixth of what we feel here on Earth, and a space elevator cable is well within our current manufacturing technology. Stretch a cable up from the surface of the Moon, and you'd have an inexpensive method of delivering minerals and supplies into Earth orbit.<br /><br />A lunar space elevator would work differently than one based on Earth. Unlike our own planet, which rotates every 24 hours, the Moon only turns on its axis once every 29 days; the same amount of time it takes to complete one orbit around the Earth. This is why we can only ever see one side of the Moon. The concept of geostationary orbit doesn't really make sense around the Moon. <br /><br />There are, however, five places in the Earth-Moon system where you could put an object of low mass - like a satellite… or a space elevator counterweight - and have them remain stable with very little energy: the Earth-Moon Lagrange points. The L1 point, a spot approximately 58,000 km above the surface of the Moon, will work perfectly.<br /><br />Imaging that you're floating in space at a point between the Earth and the Moon where the force of gravity from both is perfectly balanced. Look to your left, and the Moon is approximately 58,000 km (37,000 miles) away; look to your right and the Earth is more than 5 times that distance. Without any kind of thrusters, you'll eventually drift out of this perfect balancing point, and then start accelerating towards either the Earth or the Moon. L1 is balanced, but unstable<p><hr /></p></p></blockquote><br /> <div class="Discussion_UserSignature"> </div>

 

[webtaz99]

Considering the pounding the Moon gets from extra-Lunar objects, a little sandblasting doesn't seem like much of a problem to me.<br /><br /><br />I'm just sayin'. <div class="Discussion_UserSignature"> </div>

 

[bdewoody]

And once we've established a more or less permanent base I would guess that vehicles would land on concrete or steel pads. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[vogon13]

Lunar regolith can be solidified with microwaves. Probably cheaper to take microwave gadget to the moon than a steel landing plate.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[samkent]

>>There are, however, five places in the Earth-Moon system where you could put an object of low mass - like a satellite… or a space elevator counterweight - and have them remain stable with very little energy: the Earth-Moon Lagrange points.<br /><br />Wouldn’t you want the counter weight to extend closer to the Earth? As opposed to the balance point of the Earth/Moon gravity?<br />

 

[MannyPim]

<font color="yellow"> After reading the article "How Lunar Landers Sandblasted the Moon" on Space.com, does it make sense for a moon version of a space elevator? If there is enough force to keep the "line" extended straight with sufficient length, the negative aspects of "sandblasting" could be eliminated. Of course, it (a space elevator) would likely have to be attached around the moon's equator on the side of the moon we don't see. What would the distance be between the equator and the Moon's South Pole? </font><br /><br />Althouhg in theory it may be easire to build a Lunar space elevator, the primary reason for building a space elevator on Earth is the diffcutly and expense in achieveing LEO. <br />The Moon's gravity well being so much smaller than the Earh's along with a lack of atmosphere make the expense of building a Lunar space elevator somewhat more diffcult to justify.<br /><br />The sandblasting problem (which is rather minor) can be much more easily mitigated either with hardened / sintered landing areas/ vertical blast barriers/ or simply choosing best locations for landing and habitat sites.<br /><br />The larger problem that a Lunar Space Eleveator would solve is the "vacuum contamination". The Lunar vaccuum is one of the precious resources we have on the Moon. Anyhting (like rocket exhaust gases) that contaminate the near perfect vaccum might become a problem for large scale Lunar settlements and operations. <div class="Discussion_UserSignature"> <font size="2" color="#0000ff"><em>The only way to know what is possible is to attempt the impossible.</em></font> </div>

 

[grb3]

Thanks usn_skwerl! Some good information for review from four years ago. Lunar Lander Sandblasting probably wasn't thought of as a consideration back then. The destructive nature of exhast force in a vacuum is a bit more of a threat than some think! Thanks for the answer on the distance between equator and Poles as well.<br />

 

[grb3]

My understanding, webtaz99, is that the dust up there sticks to everything. Scattering that stuff in a vacuum may be more severe than just a little sandblasting ... especially near equipment used at a manned outpost designed to support communications and other critical functions. If it can be avoided through non-traditional propulsion means, the greater potential for the success of outcomes that would sustain life on a lunar outpost.

 

[grb3]

Imagine how much of a problem lunar dust would be until a way is found to minimize the lunar lander sandblasting effects? May seem overblown (notice the pun?), but when dust is moving at near the speed of a rifle bullet, the impact would seem significant.

 

[grb3]

Nice thought on the microwave gadget, vogon13.

 

[grb3]

Not sure that would work ... centrifigal force would seem to require the counter weight to extend the space elevator ribbon away from the earth. My thinking is that the point of attachment to the moon would be on the side of the moon we never see at the moons equator.

 

[grb3]

MannyPim, the smaller gravity well of the moon and vacuum would seem to make the space elevator more economically feasible. My concern regarding whether it could actually work is based on the lack of sufficient centrifigal force from the rotating moon. Since the moon keeps the same face toward earth all the time, the lunar space elevator could be described as someone constantly twirrling a rope connected to a ball to another rope to another ball ... the someone being the earth, the closest ball the moon, the second rope the space elevator ribbon and the second ball the counter weight.<br />

 

[usn_skwerl]

<blockquote><font class="small">In reply to:</font><hr /><p>Imagine how much of a problem lunar dust would be until a way is found to minimize the lunar lander sandblasting effects? May seem overblown (notice the pun?), but when dust is moving at near the speed of a rifle bullet, the impact would seem significant. <p><hr /></p></p></blockquote><br /><br />Moon dirt sandbags, like a reventment or typical WW2-style machine gun nest.... <div class="Discussion_UserSignature"> </div>

 

[MannyPim]

<font color="yellow"> MannyPim, the smaller gravity well of the moon and vacuum would seem to make the space elevator more economically feasible. My concern regarding whether it could actually work is based on the lack of sufficient centrifigal force from the rotating moon. Since the moon keeps the same face toward earth all the time, the lunar space elevator could be described as someone constantly twirrling a rope connected to a ball to another rope to another ball ... the someone being the earth, the closest ball the moon, the second rope the space elevator ribbon and the second ball the counter weight.</font><br /><br />The way to build a Lunar Space elvator would be through L1. IT would require a carbon nanotube ribbon about 40,000 miles long.<br />An Earth Space Elevator would be about 15,000 miles shorter in length beacuse it would only have to reach GEO. The longer Lunar ribbon means higher cost. <div class="Discussion_UserSignature"> <font size="2" color="#0000ff"><em>The only way to know what is possible is to attempt the impossible.</em></font> </div>

 

[richalex]

<blockquote><font class="small">In reply to:</font><hr /><p>The way to build a Lunar Space elvator would be through L1. IT would require a carbon nanotube ribbon about 40,000 miles long.<p><hr /></p></p></blockquote>Not so, says Wikipedia: <br /><br />"Because of the Moon's lower gravity and lack of atmosphere, a lunar elevator would have less stringent requirements for the tensile strength of the material making up its cable than an Earth-tethered cable. An Earth-based elevator would require materials at the edge of what is even theoretically possible (e.g. carbon nanotubes), whereas a lunar elevator could be constructed using high-strength commercially available materials such as Kevlar or Spectra.<br /><br />"Jerome Pearson has proposed a cable design using M5 fiber that would weigh only 6100 tonnes including a massive counterweight, that would be capable of lifting or depositing loads of 2000 N (about 1200 kg mass) at the base. The counterweight could potentially be lifted from the lunar surface."<br /><br />Wikipedia: Lunar space elevator<p><hr /></p>

 

[MannyPim]

Understood.....<br />My main point was that a much longer ribbon is needed, whatever material one decides to use.<br /><br />OF course, the underlying assumption is that some method of industrial scale CNT production will be developed and the actual cost of the CNT material will be on the same order of magnitude as Kevlar or other synthetic fibers.... <div class="Discussion_UserSignature"> <font size="2" color="#0000ff"><em>The only way to know what is possible is to attempt the impossible.</em></font> </div>