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there has been concerns about ships landing on Moon raising dust hanging around for long and thus causing issues for the following landing/launches. Looks like

by trhway 5y ago

there has been concerns about ships landing on Moon raising dust hanging around for long and thus causing issues for the following landing/launches. Looks like we're beginning such a pollution of the near-Moon space.

deleted 5y ago
[deleted]
ALittleLight 5y ago
Wouldn't asteroid (more common due to no atmosphere) impacts cause similar pollution?
- ratsmack 5y ago
  Yes, and the amount of dust would probably be proportional to the energy they carry to the impact point, and their trajectory relative to the surface.
LeoPanthera 5y ago
But the moon doesn't have an atmosphere. Surely there's nothing for the dust to "hang around" in. It would either achieve escape velocity or continue in an arc until it hits the ground again.
- SideburnsOfDoom 5y ago
  > It would either achieve escape velocity or continue in an arc until it hits the ground again. Correct. IDK about impacts, but for rocket exhausts, the surprising result is that some of the kicked-up dust can achieve escape velocity, and "where it hits the ground" is "anywhere on the moon" - denser nearby, obviously, but there's no 100% safe distance anywhere on the lunar surface. 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...
- knicholes 5y ago
  Wouldn't the dust technically become the atmosphere? There is still gravity on the moon.
  - SideburnsOfDoom 5y ago
    > douldn't the dust technically become the atmosphere? Only for short time, while it's vaporised into a gas by the impact. For that time it will join the rest of the "infinitesimal amount of gas" that forms a very tenuous atmosphere around the moon. https://www.nasa.gov/mission_pages/LADEE/news/lunar-atmosphere.html https://www.nasa.gov/mission_pages/LADEE/news/lunar-atmosphe...
  - pdonis 5y ago
    > Wouldn't the dust technically become the atmosphere? No, because it's not a gas (dust has basically zero pressure) and it won't stay aloft at a constant or nearly constant altitude. It will either fall back to the surface or escape.
    - knicholes 5y ago
      I have a hard time believing that the dust would escape given the gravity of the moon.
- ratsmack 5y ago
  Dust is generally held in suspension by the air here on Earth, because of the air currents and because of air viscosity. With no atmosphere on the moon, I suspect the dust would not stay suspended above the surface very long.
Casteil 5y ago
Moon gets struck by meteorites all the time... dust kicked up by landings or man-made impacts isn't really a problem that warrants concern.
- SideburnsOfDoom 5y ago
  > dust kicked up by landings or man-made impacts isn't really a problem that warrants concern In general no. With regards to other human people and hardware that might be on or near the moon when it's kicked up, it definitely is a concern. NASA once calculated, "when a rocket lands on the moon, or launches, how far can the kicked-up dust travel?". And got the answer "everywhere on the moon is in range. Some dust will also escape the moon." 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... > that could be bad news for any future habitats that NASA or other space agencies might want to build on the Moon > “It could ruin a spacecraft in orbit around the Moon if it just happens to be in the wrong place at the wrong time,” > will be sand-sized stuff blown completely off the Moon into orbit around the Sun.
- smegsicle 5y ago
  maybe the issue is takeoffs more than landings
samesamebutsame 5y ago
Generally the plan is to put down a pad once you've got the first ship there. There's some cool NASA concepts around for what is basically a household microwave with wheels that melts the regolith into a ceramic type material. https://space.stackexchange.com/questions/35319/can-you-really-melt-lunar-regolith-with-microwaves https://space.stackexchange.com/questions/35319/can-you-real...
- aaron_m04 5y ago
  How well does regolith absorb microwaves?
  - janto 5y ago
    According to the parent comment's link "Tiny specks of metallic iron (Fe0) are embedded in each dust particle's glassy shell [...] microwaves melt lunar soil in less time than it takes to boil a cup of tea"
    - aaron_m04 5y ago
      That's unexpectedly convenient for this plan!
aaron695 5y ago

by trhway 5y ago

deleted 5y ago

[deleted]

ALittleLight 5y ago

Wouldn't asteroid (more common due to no atmosphere) impacts cause similar pollution?

ratsmack 5y ago
Yes, and the amount of dust would probably be proportional to the energy they carry to the impact point, and their trajectory relative to the surface.

LeoPanthera 5y ago

But the moon doesn't have an atmosphere. Surely there's nothing for the dust to "hang around" in. It would either achieve escape velocity or continue in an arc until it hits the ground again.

SideburnsOfDoom 5y ago
> It would either achieve escape velocity or continue in an arc until it hits the ground again. Correct. IDK about impacts, but for rocket exhausts, the surprising result is that some of the kicked-up dust can achieve escape velocity, and "where it hits the ground" is "anywhere on the moon" - denser nearby, obviously, but there's no 100% safe distance anywhere on the lunar surface. 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...
knicholes 5y ago
Wouldn't the dust technically become the atmosphere? There is still gravity on the moon.
- SideburnsOfDoom 5y ago
  > douldn't the dust technically become the atmosphere? Only for short time, while it's vaporised into a gas by the impact. For that time it will join the rest of the "infinitesimal amount of gas" that forms a very tenuous atmosphere around the moon. https://www.nasa.gov/mission_pages/LADEE/news/lunar-atmosphere.html https://www.nasa.gov/mission_pages/LADEE/news/lunar-atmosphe...
- pdonis 5y ago
  > Wouldn't the dust technically become the atmosphere? No, because it's not a gas (dust has basically zero pressure) and it won't stay aloft at a constant or nearly constant altitude. It will either fall back to the surface or escape.
  - knicholes 5y ago
    I have a hard time believing that the dust would escape given the gravity of the moon.
ratsmack 5y ago
Dust is generally held in suspension by the air here on Earth, because of the air currents and because of air viscosity. With no atmosphere on the moon, I suspect the dust would not stay suspended above the surface very long.

Casteil 5y ago

Moon gets struck by meteorites all the time... dust kicked up by landings or man-made impacts isn't really a problem that warrants concern.

SideburnsOfDoom 5y ago
> dust kicked up by landings or man-made impacts isn't really a problem that warrants concern In general no. With regards to other human people and hardware that might be on or near the moon when it's kicked up, it definitely is a concern. NASA once calculated, "when a rocket lands on the moon, or launches, how far can the kicked-up dust travel?". And got the answer "everywhere on the moon is in range. Some dust will also escape the moon." 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... > that could be bad news for any future habitats that NASA or other space agencies might want to build on the Moon > “It could ruin a spacecraft in orbit around the Moon if it just happens to be in the wrong place at the wrong time,” > will be sand-sized stuff blown completely off the Moon into orbit around the Sun.
smegsicle 5y ago
maybe the issue is takeoffs more than landings

samesamebutsame 5y ago

Generally the plan is to put down a pad once you've got the first ship there. There's some cool NASA concepts around for what is basically a household microwave with wheels that melts the regolith into a ceramic type material. https://space.stackexchange.com/questions/35319/can-you-really-melt-lunar-regolith-with-microwaves https://space.stackexchange.com/questions/35319/can-you-real...

aaron_m04 5y ago
How well does regolith absorb microwaves?
- janto 5y ago
  According to the parent comment's link "Tiny specks of metallic iron (Fe0) are embedded in each dust particle's glassy shell [...] microwaves melt lunar soil in less time than it takes to boil a cup of tea"
  - aaron_m04 5y ago
    That's unexpectedly convenient for this plan!

aaron695 5y ago