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221 votes
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How many extraterrestrial bodies have hosted a "lander" which returned images?

To be honest, I don't know how to measure atmospheric pressure, so I cannot discriminate on that basis. Initially my answer only included unmanned missions, but based on suggestions I've decided to ...
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53 votes

ELI5: Why do they say that Israel would have been the fourth country to land a spacecraft on the Moon and why do they call it low cost?

Chandrayaan-1 hit the Moon at high speed and did not survive its "landing", which would have been much more difficult to engineer. (Its successor, Chandrayaan-2, which will actually land, is expected ...
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49 votes
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Why hasn't NASA planted a stationary lab on Mars yet?

To first answer the question ad litteram, NASA has so far successfully landed four stationary labs on Mars (Mars landing dates in parentheses): Viking Lander 1 (July 20, 1976), Viking Lander 2 (...
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48 votes
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How much more expensive are scientific instruments for space use?

Preface: I am far, far from an expert in space electronics; I don't think I can weigh in on how much these sensors actually are, which is the title question; all I can offer is an uneducated inane ...
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40 votes
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What is the deepest we have penetrated a terrestrial body other than Earth?

In July 2005, the Deep Impact mission released an impactor that excavated a crater, estimated to be 100 meters wide and 30 meters deep, into comet Tempel 1.
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  • 911
29 votes

How much more expensive are scientific instruments for space use?

I'll chime in with the other two well-stated answers. In addition to all the testing, there is the issue of "What do you do when the instrument fails a test?" Most COTS (Commercial Off-The-Shelf) ...
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27 votes
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Why is InSight's nylon parachute a "soft good"?

I'm pretty sure that by "soft good" he means it's an element of the system that can't be completely constrained from a simulation or engineering standpoint, in this case fabric. If you're working with ...
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27 votes
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Brushing clean a Mars lander's solar panels

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 ...
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26 votes
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How could a hot lander enter Titan's atmosphere without setting its hydrocarbons ablaze?

In order for a combustion process to happen, you do not only need fuel, you also need an oxidizer. On Earth, that is usually the oxygen in the air. In Titan's atmosphere, there is no oxygen. This ...
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25 votes
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Potential high temperature power sources for a Venus lander

Thanks to @MarkAddler for his search suggestions I've tried to balance length against completeness, and both lost here. However I have included enough material to try to be convincing that RTGs, ...
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25 votes

How exactly did the floor of an Apollo LM look like after EVA(s)? Seeking photo!

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. ...
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24 votes
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What cooling improvements did the Venera missions make?

According to Wikipedia launch windows to Venus occur every 19 months. In some cases multiple successful probes were launched with the same design at the same time so I'll group those together (the ...
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  • 7,076
24 votes
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What landings beyond Mars and the Moon are scheduled?

Feel free to edit this answer to add more or adjust formatting. List may be incomplete. Ordered by launch date: Hayabusa 2 and MASCOT to 162173 Ryugu, Japan/Germany/France, launched 2014, landed ...
23 votes

Is this white stuff seen by the Mars Phoenix Lander water or carbon dioxide ice?

It turns out there is a paper that discusses this exact ice patch: it's water ice, and they're referring to the white section at the top. (The small granules in the lower left may also be water ice, ...
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21 votes
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Why did the Venera missions land so close together?

The simple answer is that taken as a whole the Venera missions didn't land particularly close together. Starting with Venera 4: The overall spread of Venera landing sites (when you include the ...
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  • 7,076
20 votes

Why hasn't NASA planted a stationary lab on Mars yet?

In the 1970s, NASA sent two Viking probes to Mars. Is this the 'unmovable lab' you're looking for? The drawback of a stationary lander is that it can only gather data on one location. When you have ...
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  • 121k
18 votes

Why is Beresheet doing a only a one-way trip?

A one-way trip is much simpler and much cheaper than a return mission. a return mission is more complicated because it has to do more a return mission is much heavier (because of the extra systems, ...
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  • 121k
18 votes

How long would it have taken to launch an Apollo contingency flight?

How long would it take to launch an Apollo contingency flight, if, for example, the lunar lander couldn't get back up to orbit? There was never a facility for contingency launches on the Apollo lunar ...
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17 votes

How exactly did the floor of an Apollo LM look like after EVA(s)? Seeking photo!

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, ...
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17 votes
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When things land on Mars what fraction of their velocity do they remove propulsively?

Taking Mars Pathfinder and Viking 1 as examples: Mars Pathfinder was a direct entry at 7600 m/s and removed about 0.7-0.8% of that propulsively. Parachute deployment was at 360-450 m/s, and landing ...
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16 votes
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Why aren't landers designed to point their solar panels and radio antennas to Sun and Earth?

The Opportunity, Spirit (RIP), and Curiosity rovers all have high-gain antennas that point at Earth when in use, using a two-axis gimbal. They are used mostly to receive the command loads every sol ...
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16 votes
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How important are Philae's harpoons?

The harpoons are intended to hold the lander to the surface long enough to get the ice screws on the lander's legs in securely. The ice screws are intended as the more permanent hold-down solution. ...
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15 votes

Why hasn't NASA planted a stationary lab on Mars yet?

The short answer is that it's easier to build a rover with all the lab-stuff on it. Reuse of things in-space is harder than one might think. If there was one re-usable lab, it would need to be re-...
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15 votes
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What would the Venus landers look like today?

Let's talk about the major materials that made up the Venera landers. https://space.stackexchange.com/a/9965/25 has a great summary of what the landers were made of, they are composed of include ...
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14 votes

How does a lander get from orbit to the ground?

The minimum $\Delta V$ is effectively a Hohmann transfer. You would de-orbit just enough to barely touch the surface at periapsis, and right at the surface you would do an instantaneous impulsive ...
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13 votes
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Why has no lander or rover visited Hellas Planitia on Mars?

Hellas basin is certainly an interesting region, and several landing site selection processes evaluated candidate sites in it, mostly in the Northernmost region that's above the 30° South circle of ...
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13 votes

Potential high temperature power sources for a Venus lander

An RTG certainly can and would work on Venus, since the hot side is about 1200 C. It just wouldn't be as efficient as it would be with a colder cold side. Search for papers by Geoff Landis on this.
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13 votes
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Chandrayaan 2: Why is Vikram Lander's life limited to 14 Days?

Orbiting satellites can still have problems with eclipses, from loss of both power and heat but the total time is normally measured in minutes so simply having enough battery power to keep electronics ...
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12 votes
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Are there currently any plans for a Venus lander?

NASA's New Frontiers program has been calling for a Venus lander (Venus In Situ Explorer) on every solicitation. Venus landers are proposed every time, sometimes making it to Step 2 in the ...
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12 votes
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Will the 2018 Mars Dragon Lander be the largest lander on Mars to date?

Yes, by quite a bit. Right now the heaviest object soft landed on Mars is Curiosity, as you noted. The mass of it is 900 kg. The Red Dragon is 6400 kg, plus payload of up to 2000 kg (Maybe more for ...
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