55 votes
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Why do many comets & asteroids keep moving through the solar system, but space ships need fuel to do so?

Your assumptions are incorrect. A space ship (once it has escaped Earth) will also continue travelling - in fact it will only need fuel to change its trajectory and velocity outwith gravitational ...
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  • 13.3k
53 votes

Does NASA have an end-of-the-world policy?

First off, large life-ending asteroid impacts are very rare as there aren't many of them out there and we've found almost all of them: Looking at the 'continent' and 'global catastrophe' areas of ...
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  • 2,311
41 votes
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Legality of asteroid mining

The United States (along with Russia, China, Japan, India, and most other space-faring nations) did not sign (or in some cases, ratify) the Moon Treaty, and so companies that are registered in any of ...
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  • 1,057
34 votes
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Is Mars more at risk than Earth for asteroid collisions?

There are three factors which contribute to the difference in “apparent crateredness” between Earth and Mars. By far the most significant is ongoing erosion from weather. In Mars’ thin atmosphere, a ...
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28 votes
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What processes create an object with an interstellar velocity?

The answer to 'how can it come blazing in with enough energy to exit again' is that if it started outside the solar system it would have been unusual for it to NOT leave again, since it would have ...
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27 votes

Could a Boring Company Excavation Tool be used to create a large circular chamber inside an asteroid?

Definitely not in current shape, as it depends on tightly packed soil/rock to provide an opposing force to resistance of the ground/rock against the drill. Asteroids, with low gravity, will be far ...
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27 votes

If an extinction-level asteroid were to be detected, could we avert it?

Yes. (But it requires a bit of dishonesty.) Simply because an "extinction level" asteroid does sufficiently limit the possible nature of the object. To be extinction-level, it would need to ...
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26 votes

How hard is it to fly through the tail of a comet? Has it been done?

Ulysses, the shuttle-launched joint NASA/ESA probe to study the sun's polar regions, ran through three comet tails, more or less by chance. Ulysses Catches Record for Catching Comets by Their Tails ....
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25 votes

Is Mars more at risk than Earth for asteroid collisions?

This report shows that Mars is hit over 200 times a year by meteorites big and/or fast enough to leave a crater of typically 12.8 feet diameter. Earth strikes of this size are thankfully much rarer, ...
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24 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, ...
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22 votes
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What is the possibility of Voyager 1/2 colliding with matter (Asteroids or planetoids) present in space?

The Voyager probes are outside the Kuiper belt now, and have a very long way to go before entering the Oort cloud. They are now in a place that is almost completely devoid of matter. Or at least I ...
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20 votes
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How is it known that asteroid 2011 UW158 has so much platinum?

With all the hype in the news this was surprisingly hard to research for specifically 2011 UW158. I never did find a source for the claim on the value, though the Slooh Community Observatory put the ...
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  • 7,076
20 votes
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Does the Moon have any captured objects orbiting it?

It does not have any known objects. It seems unlikely that it would happen, although it could theoretically happen for a short period of time. There are few stable orbits around the Moon, and even ...
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  • 118k
18 votes
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Traveling through the asteriod belt?

The asteroid belt isn't nearly as dense as popular media makes it out to be. An answer from the Dawn Mission's FAQ, specifically "What is the average distance between individual asteroids? (6/13/10)",...
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  • 983
17 votes

Why do many comets & asteroids keep moving through the solar system, but space ships need fuel to do so?

Spaceships will keep travelling in their orbits just the same as comets or asteroids, without fuel. The exception is that spacecraft in low orbit are affected by the upper fringe of the atmosphere, ...
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  • 7,658
16 votes
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Can an asteroid enter Earth orbit?

Our Moon makes this possible. An asteroid with a low $V_\infty$ with respect to Earth making a close flyby of the Moon in the right direction could get into a distant orbit around the Earth. That ...
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15 votes

Traveling through the asteriod belt?

The asteroid belt is roughly 6 Astronomical Units wide, and so when it is drawn only 600 pixels wide with each asteroid a handful of pixels wide, you end up with each asteroid being five times bigger ...
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  • 148k
15 votes

How hard is it to fly through the tail of a comet? Has it been done?

Rosetta collected dust from 67P/Churyumov-Gerasimenko and analyzed it under an atomic force microscope, without landing on the cometary body itself; depending on your definitions this would seem to ...
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14 votes
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How can stellar images be "subtracted" from a sequence of exposures? (difference imaging)

The principles of Difference Image Analysis (DIA) or Difference Imaging, which is very common in modern astronomy for finding new transient sources (e.g. asteroids, variable stars, including ...
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  • 2,311
13 votes
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Could we deal with an asteroid threat given current technology?

At this point in time it seems doubtful that we could intercept and deflect an asteroid large enough to justify being deflected. This is simply a matter of momentum, a large asteroid has a great deal ...
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  • 4,133
13 votes
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Could the Orion project pusher plate model be used for asteroid deflection?

The challenge here is getting the pusher plate into position. The potential impactor is not generally traveling on an orbit that can be reached with low DV. So the only way with current(ish) ...
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13 votes

What asteroids have the least delta-v to reach?

note: This is a historical answer, and explains how to find tiny asteroids close by. The OP has clarified they want a profitably mineable-sized asteroid so there is room for more answers. Previous ...
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  • 148k
13 votes

Can we use something like RADAR to detect asteroids?

Yes, radar is one of the useful tools for detecting and observing asteroids. It is however most effective at closer ranges, like near-earth asteroid, since sending out a radio wave and bouncing it ...
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12 votes
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Could a swarm of probes autonomously establish orbit around an asteroid?

Let's break your question into separate tasks: Autonomous orbit determination (autonomous because the DSN won't be there to help you when you need it) Autonomous attitude determination Situational ...
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12 votes
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Is it possible for a human to walk on an asteroid?

It depends on the size of the asteroid. According to this article, if the asteroid's diameter is more than 8 km, you can walk on it without the fist step sending you flying off. When the asteroid is ...
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  • 121k
12 votes

Why is the Deep Space Industries Prospector 1 using water propellant instead of hydrazine?

Unlike chemical rockets such as hydrazine (a monopropellant, which doesn't require separate oxidizer and fuel to burn), water is just the reaction mass — not the energy source. The Comet-1 ...
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  • 4,524
12 votes
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Would the one million people on Mars be killed by an impact equivalent to an Extinction Level Event on Earth

I would guess no. What makes the extinction level events so dangerous for us isn't the impact or the shockwave. A shockwave on Mars won't do much damage since the atmosphere is very thin anyway, and ...
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  • 4,015
12 votes

How hard is it to fly through the tail of a comet? Has it been done?

The two Vega probes comes to mind, ending their implausible sounding mission of slipping balloons into the atmosphere of Venus with a flyby of Halley's comet in 1986. They took a heavy beating flying ...
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12 votes

What processes create an object with an interstellar velocity?

This is a very generic answer: A gravitationally bound system has a tendency to become more compact. As this happens, the gravitational potential energy becomes more negative. The energy that is lost ...
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  • 3,221
11 votes

Is it (or why is it) worse to break up a asteroid on a collision course with Earth?

The general idea behind this is as follows. After a certain size of impact, there isn't really much that will increase the devastation. So if you take two rocks, each half the size of the first, and ...
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