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SLS / Orion / Beyond-LEO HSF - Constellation => Missions To The Moon (HSF) => Topic started by: savuporo on 09/11/2016 08:49 pm

Title: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 09/11/2016 08:49 pm
This is somewhat dated, but, in 2015 KSC SwampWorks with a team from HoneyBee Robotics collaborated to test building a lunar launch/landing pad tele-robotically, in Mauna Loa analogue site.

http://www.popsci.com/this-robot-just-built-launch-pad

And a somewhat more recent summary documentary :
http://www.pacificspacecenter.com/new-documentary-on-piscesnasa-lunar-landing-pad/
https://vimeo.com/163496839
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Steven Pietrobon on 09/15/2016 06:53 am
Thanks savuporo. Its pretty clear that interlocking tiles will not work. The exhaust gases will flow between the tiles and lift them up. I think you need a large interlocking vertical surface between large bricks that has to be sealed against any gas flow.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 09/15/2016 02:33 pm
How do you seal it though ? Hard to think of a design that would use all local materials and still be easily robotically done.

I find it funny, there is such a huge gap between the various renderings of lunar bases that get put in presentations and news articles, and what actually is tried and tested.
The team spent a couple months on this in Hawaii, only to find out that telerobotics works as well for construction as it does for everything else, but their lunar construction designs are not yet hashed out.


Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: TrevorMonty on 09/15/2016 04:28 pm
Interlocking pavers may work, really depends on lander designer. Using small landing/takeoff thrusters high up on lander that are angled outward slightly will reduce force on pad. This is Xeus design approach.



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Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Steven Pietrobon on 09/20/2016 07:35 am
Interlocking pavers may work, really depends on lander designer. Using small landing/takeoff thrusters high up on lander that are angled outward slightly will reduce force on pad. This is Xeus design approach.

Its not the forces on the pad that is the problem. Its exhaust gases getting through the spaces between the tiles and then lifting the tiles up.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 09/20/2016 02:42 pm
Heavier tiles are not a likely fix either. This didn't work in normal gravity, lunar gravity is not going to be kinder.

For sealing, it'd have to be some kind of heat sintering process i'd guess. Which will be energy intensive and slow.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Chasm on 09/20/2016 07:10 pm
The PT Scientists Lunar X-Prize entry might give an answer to that.
One of their drop payloads will try to sinter the regolith. (battery powered microwave)

If that works out it opens up quite a few new options.
Testing on earth is not conclusive, at least not with their resources. Some of the available lunar regolith analoges do sinter, others just don't.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: sanman on 09/21/2016 03:07 am
Gee, I kinda imagined those tiles would fly apart before seeing the actual result of their test. I wonder why they took that approach to begin with?

What's wrong with the idea of using a tank of a liquid or slurry material and pouring it to make the pad?
Sure, you can argue that anything that was previously a liquid might be easily re-melted by the heat of the rocket exhaust, but there are other types of reactions like cross-linked thermosets, which cannot melt. It could be easy for a robot to flame-treat or flame-cure the surface of a poured material after having poured it.

Or why not unroll a carpet/rug/mat that's made of heat-resistant fibers? Maybe you have a robot with tilling and ground-stamping attachments to flatten out the ground first, and then you unroll a mat onto the flattened portion of ground, and then you nail some pegs into the ground to secure it in place.

Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 09/21/2016 05:27 am
What's wrong with the idea of using a tank of a liquid or slurry material and pouring it to make the pad?
Which liquids you'd be pouring on the Moon?
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: sanman on 09/21/2016 07:31 am
What's wrong with the idea of using a tank of a liquid or slurry material and pouring it to make the pad?
Which liquids you'd be pouring on the Moon?

What about some kind of hot molten material? How about some kind of silicone rubber or nitrile rubber? What about mixing it with lunar dust, holding it together as a binder?

But maybe the rug/mat thing would work best - maybe some kind of chainmail-linked or wire-mesh weave made from tungsten or some other high-temperature resistant material.



Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 09/21/2016 01:34 pm
What's wrong with the idea of using a tank of a liquid or slurry material and pouring it to make the pad?
Which liquids you'd be pouring on the Moon?

What about some kind of hot molten material? How about some kind of silicone rubber or nitrile rubber? What about mixing it with lunar dust, holding it together as a binder?

But maybe the rug/mat thing would work best - maybe some kind of chainmail-linked or wire-mesh weave made from tungsten or some other high-temperature resistant material.

So the point of this project was obviously to try construction with locally available materials. The bricks they used would be relatively easily made from regolith.

You wont' be able to make much rubbers out of regolith, also you'd have to have very single purpose specifc machinery to allow pouring hot rubber mix in the lunar vacuum. Also, energy intensive. Part of the point here was to use relatively general purpose manipulator that would have multiple other purposes and tasks.

Also, i suspect durability of such compound under rocket exhaust would be nonexistent, i believe.

Making a 'mat' locally would require a sophisticated fabrication process unlikely to be available in early stage, trucking it in would defeat the purpose of the project almost entirely.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Impaler on 09/23/2016 12:07 am
I would bring a bladder filled with sawdust and then fill it with water to form pykrete, this would be a solid extremely strong pad and as it ablates under rocket exhaust the byproducts would be only steam and carbon soot.  If the water can be source locally or is the waste water from a habitat then that's additional mass savings.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 09/23/2016 12:36 am
I would bring a bladder filled with sawdust and then fill it with water to form pykrete..
You wouldn't need a rocket. That mix would evaporate in absolutely no time during a lunar day.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: mfck on 09/23/2016 02:11 am
How big a lunar pad needs to be, the exhaust baring part, that is? 15m diameter? 20? How thick a metal plate do you need to counter the airflow and the temperature from a landing engine? What if it is actively cooled from the bottom?

Assuming you are able to make a decent base by compaction alone from the in-situ material, i.e regolith, wouldn't it be simpler and cheaper to just ship said metal plate? How much would a 320mē of an appropriate material weight and cost?
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Impaler on 09/23/2016 06:06 am
I would bring a bladder filled with sawdust and then fill it with water to form pykrete..
You wouldn't need a rocket. That mix would evaporate in absolutely no time during a lunar day.

First where is the requirement that the pad be used during lunar day or at an equatorial site, most interest in the moon is focused at the poles where it's permanently cold.  I'm assuming only a few uses of the pad as well as the tile based system that was experimented with is clearly not permanent either.

Second you must not be familiar with mylar, it's how we keep objects in space cold, if you reflect enough sunlight the temperature of an object remains low, the moons surface is nearly pitch black that why it can reach high temperatures after 2 weeks of uninterrupted sunlight but it is no an oven that will just melt something like leaving it out on a hot day in July.  Simply insulate the bottom of the pad and have a highly reflective skin on top and the pad will last long enough to be used.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: A_M_Swallow on 09/23/2016 12:50 pm

First where is the requirement that the pad be used during lunar day or at an equatorial site, most interest in the moon is focused at the poles where it's permanently cold.  I'm assuming only a few uses of the pad as well as the tile based system that was experimented with is clearly not permanent either.

Second you must not be familiar with mylar, it's how we keep objects in space cold, if you reflect enough sunlight the temperature of an object remains low, the moons surface is nearly pitch black that why it can reach high temperatures after 2 weeks of uninterrupted sunlight but it is no an oven that will just melt something like leaving it out on a hot day in July.  Simply insulate the bottom of the pad and have a highly reflective skin on top and the pad will last long enough to be used.

A Mylar covering would melt under the heat of the lander's exhaust, so it could only be used once. The idea of a landing pad is that it can be used multiple times.

Astrobotic is quoting a price of $1.2 million per kilogram to the surface of the Moon. Their Peregrine Lander has a maximum payload of 265 kg. That is a practical restriction on what can be sent to the Moon.
ref: https://www.astrobotic.com/payload-user-guide (https://www.astrobotic.com/payload-user-guide)
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: gbaikie on 09/23/2016 10:58 pm

First where is the requirement that the pad be used during lunar day or at an equatorial site, most interest in the moon is focused at the poles where it's permanently cold.  I'm assuming only a few uses of the pad as well as the tile based system that was experimented with is clearly not permanent either.

Second you must not be familiar with mylar, it's how we keep objects in space cold, if you reflect enough sunlight the temperature of an object remains low, the moons surface is nearly pitch black that why it can reach high temperatures after 2 weeks of uninterrupted sunlight but it is no an oven that will just melt something like leaving it out on a hot day in July.  Simply insulate the bottom of the pad and have a highly reflective skin on top and the pad will last long enough to be used.

A Mylar covering would melt under the heat of the lander's exhaust, so it could only be used once.
Patch the hole.
Quote
The idea of a landing pad is that it can be used multiple times.
Have a lot of patches to patch it with.
With takeoff use slab/panel of aerogel under rocket. Say 4 x 4' by 1 inch thick and weighing couple lbs.
Attach with Velcro :)
So multi-layer Mylar, glued between with something ablative. Top surface with Velcro attachments with patches to attach to it. A panel of aerogel which also attach with Velcro. Could have 2 x 2' aerogel panel which builds a 4 x 4'- or whatever size panel.
Also bring the ablative glue and apply with caulk gun- for edges of patches. And/or already have it on edges and have peel-away.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: TakeOff on 01/08/2017 02:00 pm
Thanks savuporo. Its pretty clear that interlocking tiles will not work. The exhaust gases will flow between the tiles and lift them up. I think you need a large interlocking vertical surface between large bricks that has to be sealed against any gas flow.
But does it matter much if the tiles are uplifted and a bit disarranged during landing? If the purpose of a Lunar landing pad to reduce the amount of debris thrown around by the descent, I would think that almost all of that problem would be solved even if the landing pad is a bit less than perfect afterwards. Plowing a wall of regolith to shield nearby pre-positioned Lunar assets could help.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: lamontagne on 01/08/2017 03:09 pm
Very interesting, thanks for finding this.  I fear sintered regolith might not be thick enough, but that really requires tests in place to determine.  As a non in situ solution, might it be possible to stake down some kind of high temperature thermal cloth, such as these?
http://www.thermalproductsco.com/high-temperature-products.html

Light metal stakes could be used to fix the blanket in place.  At 1/2 lb per ft square (1/2 inch thick), 20x20 would weigh 200 lbs.  Perhaps 1/4 inch thick could work for 100 lbs, plus 10-20 lbs of stakes.
This should be easy to test, anywhere in the world...

Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Robotbeat on 01/08/2017 03:20 pm
I question the idea that gases would get in between interlocking tiles and lift them up. There's a lot more surface area holding them down than the cracks, and the plume will be relatively diffuse, not like an air compressor nozzle poked right into the crack.

With heavy interlocking tiles in a vacuum, I bet they'd stay put.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: TrevorMonty on 01/08/2017 05:50 pm
Alternative is design lander so main engine is not used for landing takeoff stages. Use main engine for high DV deorbit burn. While landing is handled by multiple small pressure fed thrusters high up on lander facing outwards at slight angle.

There are some other benefits to this design.
Redundancy, can afford to lose a thruster at critical landing/takeoff phase. With main engine this would be fatal for lander and cargo.
Can land on regolith and not kick up rocks so they will damage lander.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 01/08/2017 06:29 pm
Two layers of interleaved tiles, with rods/nails through the edges. Use 3d interlocking pattern between top and bottom layers, instead of 2d in one layer.

EDIT: like this
http://i.imgur.com/QCDrRbM.png
http://i.imgur.com/veVMjlP.png

Red pegs can simply be part of the mold or print you use to make either top or bottom layer bricks, with matching holes on other side. If the bricks are thick enough, it'll be really hard to gases to blow the layers apart.

There are probably way better 3d interlock patterns possible, but principle would be the same - its only possible to unlock the pattern with a straight up or down motion, because of vertically aligning surfaces between two layers.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Arch Admiral on 01/08/2017 09:17 pm
The surface erosion problem is even more severe with jet-lift VTOL aircraft on Earth because the dirt, grass, stones etc. thrown up by the exhaust gets sucked back into the turbojets and wrecks them. The solution is a landing pad made of lightweight aluminum sheeting, the same kind used to make temporary runways for conventional aircraft. The idea of building a pad on the Moon out of local materials is silly. This bogus experiment was just a free vacation for some favored NASA employees.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: RocketmanUS on 01/09/2017 04:58 am
Very interesting, thanks for finding this.  I fear sintered regolith might not be thick enough, but that really requires tests in place to determine.  As a non in situ solution, might it be possible to stake down some kind of high temperature thermal cloth, such as these?
http://www.thermalproductsco.com/high-temperature-products.html

Light metal stakes could be used to fix the blanket in place.  At 1/2 lb per ft square (1/2 inch thick), 20x20 would weigh 200 lbs.  Perhaps 1/4 inch thick could work for 100 lbs, plus 10-20 lbs of stakes.
This should be easy to test, anywhere in the world...
Using a landing pad like the one you have for mars with a deflector trench lined with thermal cloth. Pad made from interlocking cut large Lunar rock or large interlocking bricks made from Lunar soil.
The second image.
https://forum.nasaspaceflight.com/index.php?topic=41427.msg1626990#msg1626990
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: zodiacchris on 01/09/2017 05:26 am
How about sintering the surface of the pad by exploding a nuclear warhead with proximity fuse? We have the technology for that..  8)
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Chris_Pi on 01/25/2017 05:53 am
How about sintering the surface of the pad by exploding a nuclear warhead with proximity fuse? We have the technology for that..  8)

And it it saves fuel by not needing to be soft-landed on the surface. Use two, One groundburst and then one at altitude and you can even dig down to solid rock, build a berm around the landing site, and clear any loose debris from the surface. Looking at weight, simplicity (Well-demonstrated complex stuff anyways), reliability and speed of operation this might actually be worth a look at. (No really. Stop laughing, I'm serious. Slightly.)
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: KelvinZero on 02/09/2017 10:28 am
And it it saves fuel by not needing to be soft-landed on the surface. Use two, One groundburst and then one at altitude and you can even dig down to solid rock, build a berm around the landing site, and clear any loose debris from the surface. Looking at weight, simplicity (Well-demonstrated complex stuff anyways), reliability and speed of operation this might actually be worth a look at. (No really. Stop laughing, I'm serious. Slightly.)
This might sound like a silly question, but would a nuclear explosion need to be particularly violent?

What I mean is, would there be much of a shock wave, or would it just suddenly raise the temperature of the ground to a predictable temperature? There is no air or anything, only the material of the bomb itself would definitely become a fast expanding ball of vapour.

If it just instantly raises say the top meter of rock to molten temperature over a few hundred meters then there is not any huge amount of material that is vaporised and expands violently, despite the vast energy that has been absorbed.

I wonder if an impact of fine dust would have a similar result. Imagine you grabbed a fast moving 1000 ton rock with a SEP tug and set in on a course that it hits some other object a while before impact, so it is a spread out cloud of grit before it hits the ground. (You can grab a fast moving rock because you don't need to bring it into orbit, just nudge it's trajectory)

I personally prefer the idea of some big inflatable lens though. You could have the thing trundling around for a year. You could make roads. You could do primitive 3d printing.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: Chris_Pi on 02/09/2017 10:29 pm
I'm not terribly familiar with how nukes work, Either in vacuum or atmosphere, So if anyone else wants to hop in and tell me how it really works feel free, I'll probably be a bit (or badly) off with this:

Heating from X-ray absorption of atmosphere (if present) makes a large part of the bang. Not going to heat uniformly down a meter. Materials heating from the radiation output will depend on what that stuff is. Mostly very rapid surface heating that can vaporize a thin layer if close enough and that can set up a shockwave in what's left and give it a good shove. Lots of energy, But dumped out too fast for conduction to move it around much. Look up Project Orion for some idea of what a bit of distance does. Plan was for hundreds of bombs set off <1km from a steel pusher plate as a propulsion system.  :o but  8)

Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: whitelancer64 on 02/09/2017 11:11 pm
I doubt anyone here is a nuclear physicist specializing in the construction of nuclear bombs, and if they were, they certainly would not be able to talk about it.

However, there's some unclassified information available from various "peaceful use of nuclear weapons" projects, from which I know nuclear material in bombs can be shaped so that the explosion goes more in one direction than another, and our nuclear weapons have been "dial-a-yield" since the 1960s so the power of the blast can be varied, and the composition of the materials in the bomb can be varied to produce blasts of greater or lesser intensity of the radiation produced so desirable portions of the EM spectrum could likely be coaxed to greater intensity.

However, for earth-moving projects involving nuclear detonations, there's a lot less control of how the ground is shaped. You get basically one result - a crater.

Just a quick correction, it was much less than 1 km from the spacecraft for Project Orion. They were planning on a detonation distance of about 60 meters, ~200 ft.
Title: Re: NASA's lunar landing pad project, built in Hawaii
Post by: savuporo on 10/08/2017 02:44 am
Summary on the project, and other lunar surface construction developments

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170002067.pdf