6 ms·

Mitigating Lunar Dust: Masten Completes Fast Landing Pad Study

99 points by radley 5y ago

ch4s3 5y ago
This seems like a super cool approach for early landers prior to the construction of dedicated landing pads.
- hinkley 5y ago
  Really at every landing site. And given the wide distribution of terrain and minerals I would be very surprised if there weren’t many sites that different countries or even teams have their eye on.
tastyfreeze 5y ago
That is a damn clever solution for one off landing pads. I wonder if a man portable "pad gun" could use the same idea, without throwing the human off the surface, to make a more permanent pad.
- NortySpock 5y ago
  Might be able to do a slower deployment method for that. A little like pouring concrete, you'd pour molten aluminum (or molten steel?) into a prepared area or crater and let it settle and cool.
  - ch4s3 5y ago
    Probably pretty expensive to get that to the moon from earth
    - WJW 5y ago
      It'll be pretty expensive no matter what the construction material is if you have to ship it from Earth, since transportation costs will dwarf any costs for the actual materials.
- ChrisMarshallNY 5y ago
  It won't come for free, though. As anyone that has ever had to work with sandblasters will tell you, running powder through things has its own challenges.
  - skykooler 5y ago
    Particularly alumina, which is literally the abrasive used in sandpaper.
NortySpock 5y ago
Masten Aerospace keeps doing super cool stuff with really elegant designs. I hope they keep winning (and keep their mojo) in the growing space race.
CarVac 5y ago
I wonder how this impacts the reusability of the engine the alumina is fired through.
- burnte 5y ago
  Little to none as it's injected into the nozzle. Engines are designed to extract maximum energy from the propellant, so the expansion curve of the nozzile is made to direct exhaust directly aft with no further expansion. When you see a rocket taking off wth a plume bigger than the nozzle, that's lost energy, but unavoidable due to the changing pressure of the atmosphere. Once you're in orbit, you can use vacuum-designed engines. Youd' inject these into the nozzle further enough down that they go directly down and out, not to the sides. You don't need to inject them with very much force at all, just enough to keep it away from the injector and near wall. You can design it so that virtually none of the material ever hits the nozzle walls.
  - lmilcin 5y ago
    > so the expansion curve of the nozzile is made to direct exhaust directly aft with no further expansion. Exactly the opposite. The gasses will INFINITELY expand as the atmospheric pressure on the Moon is for all intents and purposes exactly zero. > Engines are designed to extract maximum energy from the propellant, so the expansion curve of the nozzile is made to direct exhaust directly aft with no further expansion. Engines are NOT designed to extract maximum energy. Engines are designed for COMPROMISE between extracting maximum energy and other parameters like mass of the rocket. For example, the engine could extract more energy from the propellant if the bell was larger. But that would make it also heavier and would reduce the performance of the rocket as a system. Another example, part of the fuel is wasted to create screen to protect the engine from overheating. It is injected on the sides of the engine and does not burn. This waste is a planned compromise because better cooling mechanism would be much heavier and so wasting a little bit of fuel is best way to improve total performance of the rocket. > Youd' inject these into the nozzle further enough down that they go directly down and out, not to the sides. (...) You can design it so that virtually none of the material ever hits the nozzle walls No, you can't. You mister, need to learn some physics. The way engine works is by creating pressure. That pressure acts on the bell (the sides) and transfers to the rocket. The "sides" aren't there to ornament the rocket, they serve a very important purpose as they are the surfaces which direct the exhaust back and on which the pressure of the gasses act to propel the rocket. None of these two important roles can be fulfilled without the gasses actually pressing on them. The vacuum regime isn't any different. There is positive pressure within the bell and this propels the rocket forward as the gasses expand backwards. If you injected (ejected) fuel directly down and out you would get pitiful thrust the likes of your bottle of coke gets when a mint is dropped in it. There are engines that do what you describe (ion engines) but they work in a very different way.
LeifCarrotson 5y ago
> After the base layer is deposited, alumina particles of approximately 0.024 millimeters in diameter would be required to heat up and liquify as they pass through the engine.... The pad would then require 2.5 seconds to cool before the vehicle touches down for a safe landing. That's really, really fast solidification. I'd be worried about inadvertently sinking in or brazing the landing legs into the pad and making takeoff impossible. On investigation, though, a 6 meter diameter disc has a surface area of 28 square meters. Building that disc with 186 kg of alumina, which has a density of about 4 g/cm^3, would give you a plate with a thickness of only about 1.6 mm. I think this is just a one-time-use landing pad, not a landing-and-takeoff pad. Its purpose is to prevent lander damage and contamination of the research area by ejecta. The tech is still cool, don't get me wrong, but I guess I imagined something more like a spaceport runway with a massive slab of steel-reinforced concrete. This is more like dropping a Nomex blanket to land on than what I had in my head when I read "landing pad".
- SideburnsOfDoom 5y ago
  > a massive slab of steel-reinforced concrete. There will not (initially) be a steel-reinforced concrete structure on the moon. The best that can be done in the short term would be e.g. a covering blanket, or a application of (solar?) heat to fuse the surface.
  - trhway 5y ago
    Drop a small Wall-E with solar powered laser sinter few days before big landing. On a general note - a Dr. Evil can make Moon much less accessible just by kicking some amount of dust into low Moon orbit. One can imagine future fight tactic in an environment like this.
    - OneTimePetes 5y ago
      ? Thin foil in space, forming a covex mirror, ray of light focused on the surface, melting the spot over and over until its flat glass?
deleted 5y ago
[deleted]
RobertRoberts 5y ago
Why not drop a smaller lander first that can form the pad? Complicated solutions are a dime a dozen...
- macintux 5y ago
  This seems less complex than your idea. And much faster, and I would wager much cheaper.
- Daneel_ 5y ago
  But what does the smaller lander land on? It's landers all the way down.
  - hinkley 5y ago
    Imagine one of those drivable bridges the army has for fording rivers where there is no bridge. Make it radially symmetrical instead and use maneuvering thrusters instead of wheels. It’s going to float on the regolith, instead of water.
  - jhgb 5y ago
    Myself, when I saw this, I imagined that instead of this "spraying" approach, you could build a very flat lander, basically a large metal disk with some propulsion and support structure beneath it, and drop it just ahead of your "real" lander. Then you'd get a firm platform to land on mere tens of seconds later.
ChuckMcM 5y ago
Oh I like this very much. The previous idea I read about was a crawler that had essentially a giant microwave antenna pointed down that would "pave" where it drove by melting regolith under the antenna and then letting is cool. Of course that required landing the paver near where you wanted your payload to land, and then it had to finish before you lander came in. This is, I suspect, the "$120M" solution they alluded to on that web page.
- lmilcin 5y ago
  I wonder if the problem is as big as they are painting it. There is no atmosphere and very little gravity. The exhaust gasses expand out in a hurry and any particles should not be spending time in any kind of vortices -- should travel outward in a straight line along with the exhaust. It could technically be possible for things to maybe rebound (maybe if there are rocks nearby) and come back at the pad?
  - troutwine 5y ago
    The dust was a serious problem in Apollo and they were landing in isolated areas. It obscures landing sites and approaches that just let dust billow disturb the local regolith, meaning you kick up more dust than you might otherwise have during your mission. Future missions are almost surely going to involve landing near to existing equipment that must work for longer than the 3 days and change of Apollo 17's surface excursion, making dust management that much more important. You could, theoretically, always make your landings happen away from equipment but at 1/6th gravity with no atmosphere those sites would need to be quite far away to avoid kicking the seriously, seriously sharp dust into your equipment. But if you take that you also have to solve a hard transportation issue.
    - SideburnsOfDoom 5y ago
      > those sites would need to be quite far away to avoid kicking the seriously, seriously sharp dust into your equipment. The dust will trail off with distance, but on the moon, there is no 100% safe distance. Literally anywhere on the surface of the moon is within range to some extent. In orbit around the moon could also be in range. https://www.theverge.com/2019/7/17/18663203/apollo-11-anniversary-moon-dust-landing-high-speed https://www.theverge.com/2019/7/17/18663203/apollo-11-annive... https://www.hou.usra.edu/meetings/lunardust2020/pdf/5040.pdf https://www.hou.usra.edu/meetings/lunardust2020/pdf/5040.pdf

99 points by radley 5y ago

ch4s3 5y ago

This seems like a super cool approach for early landers prior to the construction of dedicated landing pads.

hinkley 5y ago
Really at every landing site. And given the wide distribution of terrain and minerals I would be very surprised if there weren’t many sites that different countries or even teams have their eye on.

tastyfreeze 5y ago

That is a damn clever solution for one off landing pads. I wonder if a man portable "pad gun" could use the same idea, without throwing the human off the surface, to make a more permanent pad.

NortySpock 5y ago
Might be able to do a slower deployment method for that. A little like pouring concrete, you'd pour molten aluminum (or molten steel?) into a prepared area or crater and let it settle and cool.
- ch4s3 5y ago
  Probably pretty expensive to get that to the moon from earth
  - WJW 5y ago
    It'll be pretty expensive no matter what the construction material is if you have to ship it from Earth, since transportation costs will dwarf any costs for the actual materials.
ChrisMarshallNY 5y ago
It won't come for free, though. As anyone that has ever had to work with sandblasters will tell you, running powder through things has its own challenges.
- skykooler 5y ago
  Particularly alumina, which is literally the abrasive used in sandpaper.

NortySpock 5y ago

Masten Aerospace keeps doing super cool stuff with really elegant designs. I hope they keep winning (and keep their mojo) in the growing space race.

CarVac 5y ago

I wonder how this impacts the reusability of the engine the alumina is fired through.

burnte 5y ago
Little to none as it's injected into the nozzle. Engines are designed to extract maximum energy from the propellant, so the expansion curve of the nozzile is made to direct exhaust directly aft with no further expansion. When you see a rocket taking off wth a plume bigger than the nozzle, that's lost energy, but unavoidable due to the changing pressure of the atmosphere. Once you're in orbit, you can use vacuum-designed engines. Youd' inject these into the nozzle further enough down that they go directly down and out, not to the sides. You don't need to inject them with very much force at all, just enough to keep it away from the injector and near wall. You can design it so that virtually none of the material ever hits the nozzle walls.
- lmilcin 5y ago
  > so the expansion curve of the nozzile is made to direct exhaust directly aft with no further expansion. Exactly the opposite. The gasses will INFINITELY expand as the atmospheric pressure on the Moon is for all intents and purposes exactly zero. > Engines are designed to extract maximum energy from the propellant, so the expansion curve of the nozzile is made to direct exhaust directly aft with no further expansion. Engines are NOT designed to extract maximum energy. Engines are designed for COMPROMISE between extracting maximum energy and other parameters like mass of the rocket. For example, the engine could extract more energy from the propellant if the bell was larger. But that would make it also heavier and would reduce the performance of the rocket as a system. Another example, part of the fuel is wasted to create screen to protect the engine from overheating. It is injected on the sides of the engine and does not burn. This waste is a planned compromise because better cooling mechanism would be much heavier and so wasting a little bit of fuel is best way to improve total performance of the rocket. > Youd' inject these into the nozzle further enough down that they go directly down and out, not to the sides. (...) You can design it so that virtually none of the material ever hits the nozzle walls No, you can't. You mister, need to learn some physics. The way engine works is by creating pressure. That pressure acts on the bell (the sides) and transfers to the rocket. The "sides" aren't there to ornament the rocket, they serve a very important purpose as they are the surfaces which direct the exhaust back and on which the pressure of the gasses act to propel the rocket. None of these two important roles can be fulfilled without the gasses actually pressing on them. The vacuum regime isn't any different. There is positive pressure within the bell and this propels the rocket forward as the gasses expand backwards. If you injected (ejected) fuel directly down and out you would get pitiful thrust the likes of your bottle of coke gets when a mint is dropped in it. There are engines that do what you describe (ion engines) but they work in a very different way.

LeifCarrotson 5y ago

> After the base layer is deposited, alumina particles of approximately 0.024 millimeters in diameter would be required to heat up and liquify as they pass through the engine.... The pad would then require 2.5 seconds to cool before the vehicle touches down for a safe landing. That's really, really fast solidification. I'd be worried about inadvertently sinking in or brazing the landing legs into the pad and making takeoff impossible. On investigation, though, a 6 meter diameter disc has a surface area of 28 square meters. Building that disc with 186 kg of alumina, which has a density of about 4 g/cm^3, would give you a plate with a thickness of only about 1.6 mm. I think this is just a one-time-use landing pad, not a landing-and-takeoff pad. Its purpose is to prevent lander damage and contamination of the research area by ejecta. The tech is still cool, don't get me wrong, but I guess I imagined something more like a spaceport runway with a massive slab of steel-reinforced concrete. This is more like dropping a Nomex blanket to land on than what I had in my head when I read "landing pad".

SideburnsOfDoom 5y ago
> a massive slab of steel-reinforced concrete. There will not (initially) be a steel-reinforced concrete structure on the moon. The best that can be done in the short term would be e.g. a covering blanket, or a application of (solar?) heat to fuse the surface.
- trhway 5y ago
  Drop a small Wall-E with solar powered laser sinter few days before big landing. On a general note - a Dr. Evil can make Moon much less accessible just by kicking some amount of dust into low Moon orbit. One can imagine future fight tactic in an environment like this.
  - OneTimePetes 5y ago
    ? Thin foil in space, forming a covex mirror, ray of light focused on the surface, melting the spot over and over until its flat glass?

deleted 5y ago

[deleted]

RobertRoberts 5y ago

Why not drop a smaller lander first that can form the pad? Complicated solutions are a dime a dozen...

macintux 5y ago
This seems less complex than your idea. And much faster, and I would wager much cheaper.
Daneel_ 5y ago
But what does the smaller lander land on? It's landers all the way down.
- hinkley 5y ago
  Imagine one of those drivable bridges the army has for fording rivers where there is no bridge. Make it radially symmetrical instead and use maneuvering thrusters instead of wheels. It’s going to float on the regolith, instead of water.
- jhgb 5y ago
  Myself, when I saw this, I imagined that instead of this "spraying" approach, you could build a very flat lander, basically a large metal disk with some propulsion and support structure beneath it, and drop it just ahead of your "real" lander. Then you'd get a firm platform to land on mere tens of seconds later.

ChuckMcM 5y ago

Oh I like this very much. The previous idea I read about was a crawler that had essentially a giant microwave antenna pointed down that would "pave" where it drove by melting regolith under the antenna and then letting is cool. Of course that required landing the paver near where you wanted your payload to land, and then it had to finish before you lander came in. This is, I suspect, the "$120M" solution they alluded to on that web page.

lmilcin 5y ago
I wonder if the problem is as big as they are painting it. There is no atmosphere and very little gravity. The exhaust gasses expand out in a hurry and any particles should not be spending time in any kind of vortices -- should travel outward in a straight line along with the exhaust. It could technically be possible for things to maybe rebound (maybe if there are rocks nearby) and come back at the pad?
- troutwine 5y ago
  The dust was a serious problem in Apollo and they were landing in isolated areas. It obscures landing sites and approaches that just let dust billow disturb the local regolith, meaning you kick up more dust than you might otherwise have during your mission. Future missions are almost surely going to involve landing near to existing equipment that must work for longer than the 3 days and change of Apollo 17's surface excursion, making dust management that much more important. You could, theoretically, always make your landings happen away from equipment but at 1/6th gravity with no atmosphere those sites would need to be quite far away to avoid kicking the seriously, seriously sharp dust into your equipment. But if you take that you also have to solve a hard transportation issue.
  - SideburnsOfDoom 5y ago
    > those sites would need to be quite far away to avoid kicking the seriously, seriously sharp dust into your equipment. The dust will trail off with distance, but on the moon, there is no 100% safe distance. Literally anywhere on the surface of the moon is within range to some extent. In orbit around the moon could also be in range. https://www.theverge.com/2019/7/17/18663203/apollo-11-anniversary-moon-dust-landing-high-speed https://www.theverge.com/2019/7/17/18663203/apollo-11-annive... https://www.hou.usra.edu/meetings/lunardust2020/pdf/5040.pdf https://www.hou.usra.edu/meetings/lunardust2020/pdf/5040.pdf