New answers tagged

3

Emily Lakdawalla gives an explanation in the Curiosity Update, Sols 2313-2387: Two New Drill Holes Despite Memory Problems on the website of The Planetary Society. The drilling was incredibly easy going; the rover needed to use no percussion, only drill rotation. It's possible that the easy going resulted from the rock being thinner than the length of ...


4

This caption on a photo from the Mars Pathfinder mission seems relevant: [...] The image was taken as part of a twilight study which indicates how the brightness of the sky fades with time after sunset. Scientists found that the sky stays bright for up to two hours after sunset, indicating that Martian dust extends very high into the atmosphere. And on ...


2

After the fact, we now know that Curiosity is allowed to investigate the clay unit. The first clay sample was taken in April 2019 Later samples have verified findings about water in the Gale crater, and brought data about the clay's mineral contents. The same area has also been shown to contain salt deposits The rover has followed the possible trajectory ...


5

All classic solar system planets discovered long ago without using telescopes should be visible during Marsian nights too with clear sky. After a dust storm it will take some time to get a clear atmosphere again. So we get to see Mercury, Venus, Earth, Jupiter and Saturn. But Mercury looks much smaller than Venus observed from Earth and the distance Mercury ...


6

As described in The Development of the MSL Guidance, Navigation, and Control System for Entry, Descent, and Landing, the sky crane only has the Terminal Descent Sensor (TDS), which only has a doppler radar and no camera. There are therefore no images of Curiosity during the sky crane operations


2

user34174 linked an article which explains much of the techniques used: https://www.seis-insight.eu/en/public-2/martian-science/seismic-activity To not have it lost as a volatile comment, I will paraphrase the relevant parts. A marsquake emit both p-waves (faster) and s-waves (slower). Their relative arrival time can be used to calculate the distance ...


1

Some additional information found, but no conclusive answer reached. This image was in fact also The Astronomy Picture of the Day for 1997 July 22 The Pathfinder website also calls it the "gallery" panorama, but does not mention the origin of the name. A JPL archive entry also calls it the "gallery pan", and also mentions the images it consists of where ...


2

There are a couple of potential solutions to this problem. One would be to place the mirrors at a distance just a little closer to Mars than the L2 point and let the radiation pressure counter the weak Mars net gravity field. One doesn't have to be right in line either, but a "halo" orbit circling the Mars/Sun line would allow you to balance forces while ...


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MASTCAM-Z uses the KAI-2020 sensor Sensor Data Sheet which can be read out at 18-35 Hz frame rate. The camera has 8 GB of flash memory that can be used to store video before it's trickled over to the rover computer and then scheduled for downlink. NASA Mars 2020 MASTCAM-Z Description. This is not a standard mode for the camera, but it would be possible for ...


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Strategically placed reflective material on Phobos on the tidally locked half facing mars. The mars moon appears one third compared to earths in the martian sky. If reflective, it would shine roughly ten times as bright as earths moon. Mars atmosphere is one hundredth thinner than earths. At that earths atmosphere cuts down on the affects of our moons ...


2

This could happen, although a mirror would be more likely for a number of reasons. Lenses typically aren't used for any optical surfaces larger than maybe tens of centimeters, because the glass thickness increases. A lens of such a scale would be absolutely massive. Mirrors, however, are essentially always the same thickness, aside from structural purposes, ...


2

It's theoretically possible to use a lens, but in reality it is extremely unlikely. In order stay in one place relative to Mars and the sun it will have to be at the L1 point, which is relatively close to the planet, and as the sun is relatively weak out there the lens would have to be far, far bigger around than the planet itself. This would require ...


1

Altho I'm a Mars Dust Devil researcher, my work is mostly conducted on terrestrial desert analogs (so I'd want to check my details if this were crucial... ). My understanding is that 1) the dust is re-cycled so much it's now very fine clay (2-4um), dry and often recently draped over surface roughness elements. Meanwhile, 2) weathered quartz leads to fine ...


3

As a Mars dust devil guy, I can say that the ubiquitous dust is NOT generally considered sharp-edged. Almost all of it is one of several clay minerals. Due to the absence of open water and given that the dust has been recycled continuously over many millennia (eroded, transported, deposited, re-eroded, etc), that dust is uniformly fine (2-4$\mu$m), "soft" (= ...


3

As noted in the answer by Michael, a precise chemical composition is not known at this time. We can, however, consider the overall mineral composition on the surface of the Gale Crater. This diagram provided by Curiosity's CheMin analyzer (source) shows that the composition varies with depth inside the crater: The lower part of the crater contains large ...


9

Partial answer because I learned a new word. The lines / treads on the wheels are called "grousers" and they are indeed wavy. Why: Extensive testing in JPL's Mars Yard has shown these treads better1 withstand the pressure from sharp rocks but work just as well on sand. (from the 1st link) 1In comparison to Mars Science Laboratory's wheel design


3

Mudstone, although the precise chemical composition is unknown at this time (at least to the extent I was able to find it out). From the Planetary Society, it is identified as being mudstone. Unfortunately, from wikipedia, it is clear that mudstone is a very general type of mineral and can be composed of many different things, as long as it was once ...


2

Acceleration and Deceleration costs $\Delta v$ (Delta is scientific notation for "change of something" and V stands for Velocity) of which a spacecraft has a set budget (how long the engines can burn). Here's an analogy: imagine that the spacecraft is attached by a thin string to your hand (representing Earth). You start spinning it around faster and faster,...


3

The usual answer would be that the Hohmann transfer orbit is already essentially there. But those are meant for lowest dV direct transfer - e.g. a straight shot from the Earth to Mars. They are extremely fuel efficient - the trip from Earth to Mars can take around 3.9 km/s dV - compare that to Mars' orbital velocity of about 24 km/s or the Earth's of 30 km/s....


7

There is no "stopping" in space - no matter how far you are from other celestial bodies, the force of gravity will always be tugging on you, pulling you in some direction. Within the Solar System, that tug is typically pulling you toward the Sun, unless you happen to be quite close to another planet or moon. If you were to try to get to the same path as Mars ...


70

Maybe some visual intuition for what actually happens in the Hohmann transfer helps? It's already very close to what you are describing. In the top arc, the spacecraft (yellow), is going a bit slower than Mars (red), so it's indeed "waiting" for the planet to catch up to it. It only touches the orbit of Mars in a point, but that's all we need if we time ...


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could we launch a vehicle in space for Earth, stop right on Mars trajectory... Yes, you could have a trajectory that came to a stop (briefly) in the path of Mars like how a ball thrown upwards stops (instantaneously) before falling down, except in this case you'd have to be moving directly away from the Sun on a straight-line trajectory with eccentricity = ...


38

It depends whether or not you want to orbit or land softly upon Mars, or just hit it. For the former, you have to match orbits with it, that probably means burning more fuel. For the latter, you can skip the Mars orbit injection and just crash. This is quite fuel efficient, especially as the reduced delta-V requirements mean that you need less fuel for the ...


4

You cannot "stop on Mars' trajectory" - that is not how physics works. If you want to go out as far as Mars' orbit, then expend energy to stop orbiting the sun, you will leave that orbit. This will take a lot of energy, and you will not end up in the correct orbit. Lowest dV is worked out through running multiple simulations - Hohmann Transfer seems to ...


0

It certainly 'could', there is nothing making it physically impossible, though it would require a robust docking mechanism since the the tension forces hanging 120 tonnes at the target G force would be more substantial than just docking for fuel but not insurmountable, something less than 25mm cross section in steel and it would be connecting the engine ...


4

Yes indeed, SpaceX has announced publicly about uncrewed landings on the Moon before 2022 ! From the article Spacex wants to land Starship on the Moon before 2022, then do cargo runs for 2024 human landing: "Aspirationally, we want to get Starship to orbit within a year", Shotwell said. "We definitely want to land it on the Moon before 2022. We want ...


4

Earth has a much larger and fluffier atmosphere than Mars. Mars’ atmosphere provides little deceleration until about 50km or below (depends on location and angle), but then the deceleration turns on quite solidly. The result is a very narrow window to do any maneuvering in the brief interval that the speed is dropping. Source, originally from ...


5

Phobos, on its surface, has some protection against radiation beyond being just in deep space. But the real advantage comes where Phobos is easy to dig in to, and thus you could have a habitat under the surface of the planet. But if you compared the surface of Mars and the surface Phobos facing Mars, you would probably get roughly equal exposure. The ...


4

There is a popular idea that has been put forward that one can return to Earth via Venus, and to achieve that one has to launch within a few weeks of landing on Mars. I suspect that the author is confusing that. You can take a look at http://clowder.net/hop/railroad/sched.html for when the times are, and see that the times pretty closely overlap. ...


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