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25 votes

Can we expect to find pure iron or only nickel-iron alloys in asteroids?

Finding macroscopic (i.e., big enough to actually use) pure-iron meteoroids appears to be extremely low-probability. Certainly the bulk composition of the metals in Earth (good references here, here, ...
Tom Spilker's user avatar
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25 votes
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What is the danger of creating micrometeorite clouds orbiting the Moon by constantly landing spacecrafts on its surface?

In general terms any particles placed on an orbit by a single impluse will pass through the point that impulse was applied again one orbit later. So for dust kicked up from the moon surface it will ...
GremlinWranger's user avatar
11 votes

Is it possible for something to fall straight down to earth? What are the requirements?

Sure it's possible. There is two ways for this to be achieved: For an earth satellite; cancel all forward velocity. The satellite will then start being attracted by earth gravity and fall ...
Antzi's user avatar
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8 votes

Is it possible for something to fall straight down to earth? What are the requirements?

Obligatory XKCD Forgive me for assuming this, but it seems like you don't quite understand what an orbit is. As XKCD Puts it "Space is not up, space is sideways very, very fast." To put it another ...
UIDAlexD's user avatar
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7 votes
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How long can a high altitude balloon fly before a meteor hits it?

Here's a rough estimate. From the curves at top left of the plot in figure 1 in this paper, we can expect on average, per year per million km2 of earth surface, 4.5 meteors, weighing 31 grams ("log m"...
Camille Goudeseune's user avatar
7 votes
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Who discovered "Egg Rock"? The Curiosity rover or people?

People did! Re-reading the linked article in ASU's Red Planet Report, I noticed at the end it links to an additional article; "More on Egg Rock at redplanet.asu.edu/?p=21047". That link says:...
uhoh's user avatar
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6 votes
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Is there a meteorite from Earth on Mars?

There should be. It needs a huge impact on Earth to send material all the way to Mars but we get them occasionally. You need something of the order of the Chicxulub impact 66 million years ago. The ...
Robert Walker's user avatar
6 votes
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Why doesn't the perchlorate on Mars' surface oxidize metallic meteorites?

As it turns out, perchlorate is actually rather unreactive under Martian surface conditions, and this actually explains the unusual abundance of perchlorate there: In any case, most of the chlorine ...
called2voyage's user avatar
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6 votes

99.99% pure iron meteorite

I'm highly skeptical that a 99.99% pure iron meteorite would be a fragment of a natural solar system object. It's more likely you have a shard, maybe part of a bolt or some such (hmm, I just thought, ...
Tom Spilker's user avatar
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6 votes

Can we expect to find pure iron or only nickel-iron alloys in asteroids?

Between the orbit of Mars and Jupiter, you can find the Asteroid Belt. The total mass of all of the asteroids is about 4% that of the Moon. About 10% of the mass is thought to be M-type (metal-rich) ...
gwally's user avatar
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5 votes
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Where are the meteorite remnants related to the craters they've produced on the moon?

All over the place But as the whole surface of the Moon is either rock, or rock broken by meteor impacts, or meteors, it becomes very difficult to identify them. Moon meteorites will have none of the ...
CuteKItty_pleaseStopBArking's user avatar
5 votes

Can we expect to find pure iron or only nickel-iron alloys in asteroids?

I have very good information for you! I confirm that there is pure iron in space because I have a 99% iron meteorite. This samples weight 42,38g, and the fusion crust is no longer visible because I ...
Siliman's user avatar
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4 votes
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What is the methodology to determine a meteorite strike vs space debris?

Space debris and meteoroids (they become meteorites when they hit the Earth) differ significantly in velocities with respect to the Earth. Space debris are more predictable since their trajectories ...
mizix's user avatar
  • 56
4 votes

How was the 18 December 2018 Bering Sea Fireball detected and characterized? Was it a serendipity or a weather satellite?

There is a network of satellites designed to detect ballistic missile launches. The key feature in each of these is very high temperatures moving at fast speeds. Thus, the easiest way to look for them ...
PearsonArtPhoto's user avatar
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4 votes
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How are meteoroids, asteroids and debris in space tracked?

Space debris is tracked via radar. Asteroids are usually tracked via optical telescopes set up for that purpose. If they get really close to Earth, they may be tracked via the space debris systems ...
Hobbes's user avatar
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3 votes

Is it possible for something to fall straight down to earth? What are the requirements?

One possibility is to launch straight up. Read about sounding rockets and Blue Origin New Sheppard vehicle. If you launch straight up and do not reach escape velocity, you will come almost straight ...
jkavalik's user avatar
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3 votes
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How was the 18 December 2018 Bering Sea Fireball detected and characterized? Was it a serendipity or a weather satellite?

In the NPR News item and podcast Former Astronaut On Watching For Life-Destroying Objects From Space Reporter Lulu Garcia-Navarro interviews physicist and former NASA astronaut Ed Lu, currently the ...
uhoh's user avatar
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3 votes
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What is used to monitor objects burning up in the atmosphere on descent?

There's a "Global Infrasound Network" that monitors for nuclear explosions. If a reentry is big enough, I expect they'll "hear" it. It might have to be pretty big, perhaps larger ...
Bob Jacobsen's user avatar
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3 votes
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Does Perseverance's SuperCam include a Martian meteorite? If so, why?

The meteorite is part of the SuperCam Calibration Target (SCCT) on Perseverance. From the paper "SuperCam Calibration Targets: Design and Development": As a nod to the notion of return ...
KarlKastor's user avatar
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3 votes
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What do the insulation and meteorite protection layers being opened on the Soyuz MS-09 spacecraft look like?

The forums at nasaspaceflight.com have some stills captured from the NASA broadcast of the EVA. The cut and peeled back insulation is shown well in this shot. A higher-resolution version of this ...
BowlOfRed's user avatar
  • 6,882
3 votes

What do the insulation and meteorite protection layers being opened on the Soyuz MS-09 spacecraft look like?

A anti-meteorite screens (about a millimeter thick) https://life.ru/t/наука/1155250/samaia_vazhnaia_ekspieditsiia_chiem_zaimutsia_kosmonavty_na_mks There are anti-meteorite screens deployed on the ...
A. Rumlin's user avatar
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3 votes

How much more likely is it for a colony on Mars to receive a damaging meteorite hit than a similar structure on Earth?

This is an interesting question! Partial answer! I don't know about the frequency of Martian meteorites, but for a given one we can estimate its terminal velocity (if it reaches it) and kinetic energy....
uhoh's user avatar
  • 149k
2 votes

How much more likely is it for a colony on Mars to receive a damaging meteorite hit than a similar structure on Earth?

Uhoh's answer neatly covers the damage a given meteorite would have upon impact. I'll add to that approach the likelihood that a meteorite even strikes Mars or Earth. A Martian year is 1.6 times ...
ChrisR's user avatar
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2 votes

Did the rovers' cruise balance masses have a noticeable impact on Mars?

Photos from Mars Reconnaissance Orbiter show the impact sites from Curiosity's 2 main ballast weights about 80 km from the rover, plus the impact sites of the 6 smaller weights jettisoned just before ...
giles tester's user avatar
1 vote

How much more likely is it for a colony on Mars to receive a damaging meteorite hit than a similar structure on Earth?

The original OP's question Could meteorites prevent Mars exploration? has been transformed into another question that was answered, though partially, into energetic calculations and probabilistic ...
Ng Ph's user avatar
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1 vote

What is used to monitor objects burning up in the atmosphere on descent?

Several satellite radar tracking stations are being used to track the doomed station. This .png is updated every few minutes by The Aerospace Corporation. In the lower left a list of tracking radars ...
Organic Marble's user avatar
1 vote

Is a Moon-base inherently more dangerous than a Space Station?

How safe a space settlement is depends on how well-established it is. The very first lunar base using inflatable structures would be vulnerable to radiation and small meteors as well as a critical ...
Johnny Robinson's user avatar
1 vote

What maximum speeds can be expected from meteorites?

Clearly, the answer has to be a probability distribution. The actual distribution would necessarily "encode" the past history of the galaxy, neighboring galaxies, etc. Since a fast-moving object has ...
user22563's user avatar
1 vote

What maximum speeds can be expected from meteorites?

My understanding from basic physics is that when you calculate the requirements for escape velocity from a body's gravitational pull, the math is also able to point out the maximum accumulated ...
MikeS's user avatar
  • 11

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