# Tag Info

53

Two main reasons really: The dust on the Moon, while it would be extremely fine-grain, is also highly charged due to Sun's radiation and solar winds, so it would stick quite good to the surface, grain to grain, but also cling to astronauts' space suits, something that was made quite apparent when they had fairly big problems getting it off and somewhat ...

34

Yes. The fear that lunar dust was fine, deep, and motile enough that a lander could sink under its surface was mostly backed by Thomas Gold, a noted astrophysicist who was a consultant to NASA in the 1950s. Note especially in the image below of a Popular Mechanics article from 1964, the quote from his article in Science magazine on the subject: "Without ...

33

Part of this is also discussed in the How can Mars have dust storms with such a thin atmosphere? thread, but yes it would be abrasive, and direct evidence for this can be appreciated in all kinds of aeolian formations on the Martian surface, like the dunes of the Nili Patera region or the ones in the Lyot Crater, just to name a few of the most well know ...

25

In this video of the Apollo 11 landing, you can see dust being blown away during the approach (from ca. 4:30). Some of the particles were blasted clear over the horizon and may have ended up halfway across the moon. The 'ground' below the dust isn't smooth. Like new basalt, it has a grainy texture, as you can see here directly below the exhaust: The ...

24

There was an expectation that there would be some dust, however, there were a number of surprises associated with this dust. Apollo astronauts tried to remove dust using vacuums and brushes. This failed to work because the dust is electrostaticly charged, it sticks to everything. The summary of all of the mission in the NASA report quite quite interesting, ...

24

Looking through the images on the Apollo Archive, which I believe to contain all publicly available images and checking the ones at the end of EVAs I was not really able to find anything satisfactory. The best ones were before lunar takeoff of Apollo 17 None of them directly shows the floor however. The second one shows a little compartment for the helmets. ...

20

Reasons not to provide mechanical means to clean solar panels on Mars: and this is the primary reason: Wind on Mars occasionally blows the dust away. This means dust is not a major issue, but a minor one. Spirit and Opportunity functioned for years despite not having dust removal equipment. Mechanical operations are expensive: you've just added a series ...

18

Mostly a product of two environmental factors, I would wager: Lack of in-air humidity or liquid water on the ground keeping dust fine grained and not sticking together to form larger mass particles, and Relatively low surface gravity of roughly 1:2.6 when compared to the sea-level gravity on the Earth keeping them suspended in atmosphere for longer periods ...

18

Escape from planetary atmospheres of the terrestrial planets in our solar system is dominated by ions in absolute numbers, as opposed to neutral particle species. Particles can be any type of molecule or atom here, mostly $\mathrm O^{+}$ and $\mathrm N^{+}$ for Earth. For the case of Earth, a particle, once ionised in the upper thermosphere, can couple to ...

17

The best physical evidence is the fact the foot pads of the lunar lander were dish shaped pads and not something smaller. This is not evidence of DEEP dust, but of at least the belief there was SOME dust likely to sink into.

15

How exactly did the floor of an Apollo Lunar Module look like after EVA(s) during an actual Apollo mission (before or during launch from the Lunar surface into Lunar orbit)? Besides, by any chance, how did the hatch and its sealing look like? I'd figure all of it was all pretty dusty ... I am looking for at least one actual photo! First to show floor ...

14

The gear boxes are sealed, often a labyrinth seal. Opportunity has been operating for almost ten years with many actuators still working fine.

12

They will likely be relying on two things: Since the rate at which dust will accumulate on the solar panels is pretty well known, they can estimate a lifespan of the rover. All space probes have some form of estimated lifespan, and the primary science mission is generally planned to fit within that low timeframe. However, as we've seen from Spirit and (...

12

Moon dust was a problem. Lunar Module dust, dirt and debris contamination presented numerous challenges for several of the Apollo missions. The Apollo 12 crew observed that at 1/6-g the cabin atmosphere was excellent, however, after orbital insertion lunar dust filled the atmosphere and caused eye and nose irritation. [...] The Apollo 16 crew appears to ...

10

The answer is that the solar radiation heats the thin atmosphere of Mars but hot air rises up and it also lift its small dust (since Mars has low surface gravity of 3.711 $m/s^2$ they are almost weightless) and dust-storms begin to form, swirling at great speeds due to the thin atmosphere probably due to formation of different pressure in the atmosphere (...

10

The winds on Mars are much faster than typically on Earth, however, the atmosphere is much thinner. This can cause some unusual effects, somewhat analogous to high speed/ low torque vs low speed/ high torque. Let's assume the satellite dish had a surface area of $1 m^2$, a reasonable assumption. Also, let's use the math from this question, and let's use ...

10

A starting point for checking orbital stability is the Sphere of Influence for short term stability (or rather, to select a suitable frame a reference in the patched conic approximation), and the Hill sphere for more long term stability (satellites). $$r_{SOI} \approx a\left(\frac{m_{satellite}}{m_{parent}}\right)^{2/5}$$ For a reference spacecraft, I'm ...

7

Retrorockets could accelerate dust particles and smaller stones to a lot higher velocities than highest recorded wind gusts on the surface of Mars that reached 500 to 600 km/h (300 to 375 mi/h). For example, the Apollo Lunar Modules' descent engines blew out high-velocity lunar particles estimated to have reached speeds of between 0.6 and 1.5 miles per ...

7

There is an excellent series called "Moon Machines" that is often shown on the Science Channel and is also available on DVD. The episode "The Lunar Module" discusses the fact that NASA was concerned that lunar dust might be deep enough for the lunar lander to sink into it. In my opinion, this series is an excellent documentary of the Apollo Program well ...

7

This reference provides this handy table: There hasn't been a global dust storm since 2007. This paper classifies regional dust storms in Martian years without a global dust storm into three categories, with starting LS's of 210° to 240°, 245° to 260°, and 305° to 320°. Note that we have been watching dust storms on Mars for a limited time, so the data is ...

7

It did perform the observations, but nothing was detected. Here is an article that covers this Surprisingly, the LADEE science teams' preliminary evaluation of the data has not revealed any effects that can be attributed to Chang'e 3. No increase in dust was observed by LDEX, no change was seen by UVS, no propulsion products were measured by NMS. ...

7

Basically it is blown away by the solar wind, headed to interstellar space. A light particle in orbit around the Sun will tend to be pushed further out with time because of both solar wind and photonic pressure. Note there are a few pockets of dust around, but they are very hard to see. It takes being in a relatively stable point, usually the L4/ L5 points ...

6

NASA SP-530 "Apollo Expeditions to the Moon", edited by Edgar M. Cortright, which is available on the NASA History Program Office website, states that prior to the landing of Surveyor I on the moon: Some scientists had theorized that astronauts could be engulfed in dangerously deep dust layers It does not detail whether these claims were taken seriously ...

6

I did some research, and according to this source, Philae has only one, upward-pointing, thruster, the "Active Descent System". It has no downward-facing thrusters that could kick up dust. This thruster will likely only be used when Philae is already on the ground to keep it there while it anchors itself, not for course correction. Rosetta contains a ...

6

If the CM and LEM were built in clean rooms, it wasn't because of dust itself being a problem. They were trying to prevent materials from Earth contaminating the Moon rock samples. The Moon dust turned out to be somewhat of a problem (it's nasty stuff). But there was no weight budget for an airlock.

6

Nobody knows! We've never done radar sounding of Phobos, and we have no idea what lies beneath its layer of dust. We can surmise minimum depth by looking at craters - the estimate range is 5 - 100 meters. There does appear to be significant variation, likely because of the Stickney impact, which laid many (can't remember number) meters of ejecta, and because ...

5

Dust on Mars, and on the moon, is very, very fine. There's no water, so there's no clumping or mud, no washing into basins to form clay or sedimentary rocks. On the Apollo missions, moon dust got through zippers, through filters, it got into everything and became a hazard. If you look at the famous footprint picture you can see how fine it is, like flour, ...

5

Those are the radial spars that give the solar array rigidity once it's fully deployed. Image Source: The Space Technology 8 Mission; S.F. Franklin, et al. The landing site for InSight was selected to be a low dust environment. Clearing events are not expected during the time of the mission. As far as I can tell, dust collection was not a consideration in ...

5

The Mars 2020 rover uses a Radioisotope Thermoelectric Generator for power, so it doesn’t have any solar panels. It looks like the helicopter has its solar panel on top of the rotor. Flight vibrations will likely remove dust sufficiently. The helicopter may be able to remove dust from the rover for other reasons, but the main concern there is avoiding ...

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