55
votes
Accepted
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 ...
- 13.7k
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 ...
- 2,506
34
votes
Accepted
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 ...
- 167k
34
votes
Accepted
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, ...
- 3,085
28
votes
Accepted
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 ...
- 21.4k
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 ...
- 54.9k
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 ...
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
....
- 178k
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, ...
- 18.2k
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, ...
- 351
23
votes
Accepted
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 ...
- 17.6k
18
votes
Accepted
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
18
votes
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 ...
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, ...
- 8,627
16
votes
Accepted
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 ...
- 58.5k
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 ...
- 149k
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 ...
- 167k
15
votes
Accepted
How to maintain balance and center of gravity when pushing a 100-ton piece of asteroid?
Two observations:
Any reasonable way of nudging a NEO towards Earth requires doing a burn months or even years in advance. Compared to the burn time (here 1min), that means we have a lot of time to ...
14
votes
Accepted
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 ...
- 2,506
14
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 ...
- 149k
14
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 ...
13
votes
Accepted
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) ...
- 21.4k
13
votes
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 ...
- 73.2k
13
votes
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-...
- 1,788
13
votes
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 ...
- 231
13
votes
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 ...
- 1,584
13
votes
Accepted
Gravity assist (flyby/slingshot) from an asteroid?
Asteroids are too small to give a meaningful boost from a flyby.
During an encounter, the relative entry and exit speed is equal
$$ v_{in} = v_{out}$$
The only thing a mass does it bend the direction ...
12
votes
Would an asteroid collision affect the Moon's orbit, and what consequence would that have for Earth?
The Moon's mass is 7.34 × 10$^{22}$ kg. For an asteroid to have a noticeable effect, its mass must be in that ballpark.
the asteroid mass needed also depends on its speed (kinetic energy).
what time ...
- 126k
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 ...
- 4,548
12
votes
Accepted
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 ...
- 4,585
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