# Tag Info

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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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### 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 ...
• 2,341
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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 ...
• 1,057
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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 ...
• 162k
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### How could 99942 Apophis, in 2029, be captured and brought into a low Earth orbit?

The edge of Earth's Hill Sphere is about 929000 km, so in order to capture Apophis, it needs to decelerate from a hyperbolic orbit to an elliptical one with an apogee of at most 929000 km. In 2029, ...
• 2,976
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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 ...

### 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 ...
• 53.4k

### 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 ...

### 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 ....
• 167k

### 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, ...
• 351

### 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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### 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 ...
• 7,126
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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 ...
• 120k
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### Is there any evidence from previous missions to asteroids that said asteroids have minable minerals?

There have been no sample return missions from M-type (metallic) asteroids. Their composition has been estimated from spectroscopic data and radar albedo. The IR spectra of these asteroids was matched ...
• 9,254
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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)",...
• 1,043

### What caused the jitter in the DART video as it approached Dimorphos?

This is an extended comment to your self-answer, so I'm making it community. From your answer, As to why they weren't able to do a single, early course correction and just glide smoothly in for the ...

### 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, ...
• 8,492
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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 ...
• 58k

### 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 ...
• 148k

### 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 ...
• 162k
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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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### 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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### 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 ...
• 4,183
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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) ...

### 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 ...
• 148k

### How could 99942 Apophis, in 2029, be captured and brought into a low Earth orbit?

In 2029? We can't. I doubt that that the next two closest approaches after 2029 (2036 and 2051) are within reach. We might be able to do it by 2116, or maybe even 2066. An object as large as Apophis ...
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### Is there an elegant method to stop an asteroid's spin?

I found at least 1 paper proposing enclosing the asteroid in a bag filled with gas. https://www.researchgate.net/publication/273913280_SHEPHERD_A_Concept_for_Gentle_Asteroid_Retrieval_with_a_Gas-...
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### Is there an elegant method to stop an asteroid's spin?

Look at how satellites are commonly de-spinned, and apply it on a larger scale. A commonly done method is the Yo-yo de-spin where you have long ropes with weights, and extending them slowy from the ...
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### Is there any evidence from previous missions to asteroids that said asteroids have minable minerals?

Iron? Maybe, but... The first material being considered for mining (you may be surprised to find out) is water. The processes for mining water are generally well known and benign (ice has a very low ...
• 1,526