54 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 ...
Nathan Tuggy's user avatar
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50 votes
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Why do we need to make probes land on other planets or moons?

You can always learn more by a closer inspection. You may read articles about materials being detected by spectrometry from orbit, but don't let that give you the impression that humans have the ...
Mark Foskey's user avatar
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 ...
0xDBFB7's user avatar
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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.
Jim Lewis's user avatar
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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) ...
Tom Spilker's user avatar
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28 votes
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Can the Mars lander's/rover's solar panels be cleaned?

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 ...
Hobbes's user avatar
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27 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 ...
SE - stop firing the good guys's user avatar
26 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 ...
Dragongeek's user avatar
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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, ...
uhoh's user avatar
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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. ...
Hans's user avatar
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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 ...
24 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, ...
Andrew is gone's user avatar
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, ...
Hobbes's user avatar
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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 ...
Russell Borogove's user avatar
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, ...
Rob's user avatar
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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 ...
Christopher James Huff's user avatar
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 ...
PearsonArtPhoto's user avatar
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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.
Mark Adler's user avatar
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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 ...
GremlinWranger's user avatar
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 ...
PearsonArtPhoto's user avatar
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12 votes
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Why do all recent proposed lunar landers have payloads on top?

Without having access to the proprietary design documents of these landers, it will be impossible to give a definite answer. However, there are a few observations and guesses we can make. First of all,...
Polygnome's user avatar
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11 votes

What is the deepest we have penetrated a terrestrial body other than Earth?

The non-comet runner up is probably the crater on the moon created by the impact of the Centaur upper stage from LCROSS. NASA estimated that at "approximately 28m (92 feet) in diameter by 5m (16 feet)...
Simon's user avatar
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11 votes
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Why was there never a lander for the Martian north polar cap?

The polar ice caps of Mars are more challenging for a number of reasons. Mars has a similar tilt to Earth, which means that the polar regions have some of the same problems. The two main problems are ...
PearsonArtPhoto's user avatar
  • 121k
10 votes

What is the deepest we have penetrated a terrestrial body other than Earth?

Since the question is about terrestrial bodies, maybe the Deep Space 2 mission penetrating about 0.6 m (or 2 ft) into Mars was the deepest. At least that's what it was designed for, but we don't know ...
Everyday Astronaut's user avatar
10 votes

How much more expensive are scientific instruments for space use?

Just to give you an idea, here is how the cost might break down. The COTS version will need to be torn apart to survive vibration testing, along with added material. It will need to have some kind of ...
PearsonArtPhoto's user avatar
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10 votes
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Could InSight lift off and move somewhere else?

Possible, but very likely to cause damage to the spacecraft. Let's look at the lander's systems: Engines: reusable. InSight uses 20 thrusters of three different models, all built by Aerojet. They ...
DrSheldon's user avatar
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10 votes

Rover vs pathfinder vs lander?

NASA has helpfully provided a list of spacecraft classifications which covers these terms (and more.) Rover: a vehicle. There have been 4 rovers on Mars: Sojourner, Spirit, Opportunity and Curiosity. ...
Hobbes's user avatar
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10 votes
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What is the purpose and necessity of this giant structure being used in tests of China's Mars lander?

According to Quanzhi Ye (via tweet; while not a primary source, he is planetary scientist who understands Chinese) it is for simulating Mars' lower gravity while testing obstacle avoidance for the ...
astrosnapper's user avatar
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10 votes
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How difficult is it to convert a hypergolic based Moon human lander to a cryogenic one?

There will likely be significant differences in the required tankage, if nothing else. The paper Lunar Lander Conceptual Design shows a comparison between landers with similar payload requirements ...
Organic Marble's user avatar

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