54
votes
Accepted
Why not explore Cruithne?
3753 Cruinthe ranks as target number 16832 in JPL's list of near earth asteroids that might be worth visiting, someday. With 16381 better targets, that "someday" most likely will be a long time from ...
- 72.5k
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
23
votes
Accepted
How feasible is a manned flight to Apophis in 2029 using Artemis or Starship?
There's no point in a flyby since there would be no time to conduct any meaningful measurements.
According to Wikipedia, 99942 Apophis will be going about 7 km/s relative to Earth at closest approach ...
- 956
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 ...
- 58.4k
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) ...
- 20.9k
13
votes
Why did they think that S509356 was in orbit around the Earth? Where is the disconnect?
Short answer is that you are confusing two different names: S509356 and 509356s.
The 509356 in the JPL Small Body Database used by HORIZONS is not the same body as the S509356 you mention. Searching ...
- 361
13
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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 ...
- 72.5k
10
votes
Accepted
Can we destroy an asteroid by spinning it?
Not really. If an asteroid that was a loose collection of rubble was spinning, it would fall apart. The question is, how do you get it spinning? And would it do any good anyways?
To make it spin one ...
- 121k
10
votes
Do all dangerous asteroids first pass through keyholes?
Dangerous asteroids are those that can hit the Earth, and are large enough to cause substantial damage. There are currently no such known asteroids. (2020-02-21)
There are two ways an asteroid could ...
8
votes
Can an asteroid enter Earth orbit?
Aerobraking would not work. If the asteroid shaved off enough speed to put it into orbit, the orbit would be highly eccentric resulting in repeated encounters with the atmosphere and eventual impact.
- 81
7
votes
Accepted
How will NEA Scout control its attitude during deep space flight & keep its camera steady without vibrations or damage to its 85 m² solar sail?
The NEA Scout contains multiple items aimed at controlling attitude:
An inertial measurement unit that contains rate gyros that sense the vehicle's rotation rate with respect to inertial,
A star ...
- 72.5k
6
votes
Accepted
Are there any specific plans for how to deal with near-Earth comets? If not, should there be?
The threat from comets gets a lot less attention for several reasons:
the threat from comets is about 1% of that from asteroids (executive summary of the 2017 Report of the Near-Earth Object Science ...
- 2,496
6
votes
Accepted
What precisely was the character of the non-gravitational acceleration of Oumuamua?
There is a paper on this subject that you can read here. Basically by fitting the data to a pure gravity simulation, there was some residuals, but when fitting it to the model $A_1r^2$, they could ...
- 121k
6
votes
Accepted
How will OSIRIS-REx scan and characterise the near-earth asteroid Bennu?
OSIRIS-REx is packed all full of good stuff. I'll throw together a quick list of the scanning ones you're interested in.
Also of note is that the entire spacecraft will be making that scanning ...
- 1,266
6
votes
NEAR Shoemaker mission data
All the data from the NEAR Shoemaker mission is archived at the Small Body Node of the NASA Planetary Data System. Asteroid surface properties (the regolith) is normally measured using images or ...
- 2,496
5
votes
Accepted
Why are low-albedo asteroids thought to be more water-rich?
It's a Bayesian thing. If one spots a low albedo asteroid, the odds are good that it's a carbonaceous chondrite asteroid that formed beyond the frost line and hence contains minerals that have become ...
- 72.5k
5
votes
Scenarios for asteroids 2000 QW7 and 2010 CO1 hitting the Earth?
There are no scenarios for either of those asteroids hitting the earth on the next approach. Both have been tracked carefully for years, and the closest approach has been calculated at 0.035428 ...
- 19.9k
5
votes
Accepted
How did fictional asteroid 2019 PDC get its name?
The scenario is presented by the 2019 Planetary Defense Conference.
- 166k
5
votes
Could the Orion project pusher plate model be used for asteroid deflection?
This depends on the size and composition of the asteroid. Many asteroids are loose rubble piles, held together by weak gravity only. So you can't really park a small ship on the surface and start ...
- 124k
5
votes
Accepted
How big would a collection of asteroids near the Moon's L4 point need to be to aggregate naturally into a "stepping stone" for space exploration?
Not touching upon how "useful" this could be as a stepping stone, as that's difficult to answer, but the more narrow question "Will a pile of rocks stick together at EML4, or drift apart due to tidal ...
5
votes
Accepted
Could a laser array and miniature light sails be used to deflect asteroids that are on a collision path with Earth?
Yes it would work.
But no, it would not work very well at all.
If you are going to have the supremely powerful laser array available, you would be better off beaming the asteroid directly. The ...
5
votes
How could 99942 Apophis, in 2029, be captured and brought into a low Earth orbit?
The Hill sphere delta-V is the minimum possible for Earth to capture Apophis from the Sun. To go all the way to LEO, as in the question title, you have to decelerate a lot more than that.
Note first ...
- 7,628
5
votes
How feasible is a manned flight to Apophis in 2029 using Artemis or Starship?
It might be possible in theory, but it would require a dedicated development campaign. It won't happen in practice as the powers that be have no interest in doing it. Most eyes are focused on the Moon ...
- 8,742
4
votes
Accepted
Could we reverse gravitational slingshot a fast object to slow it down and capture it in an orbit?
You can certainly reverse a gravity assist to lose velocity. Most inner system probes do so.
For a classic gravity assist the object has to leave the influence of the assisting body so for capturing ...
- 20.9k
4
votes
Accepted
Here it comes! 2012 TC4 has been re-acquired and its orbit revised; at over 50 million km, how was this done?
As reported on the Minor Planets Mailing List, 2012 TC4 was recovered by the European Southern Observatory's Very Large Telescope in Chile. Here's their reported astrometry data. According to the ESO'...
- 10.1k
4
votes
Accepted
Just how close to Earth will 2012 TC4 pass in 2017?
It looks like the tweet is screenshot of JPL's NEO close approach table (found here). JPL has definitions of many terms here.The 'nominal' miss distance is based off the latest/greatest prediction of ...
- 1,292
4
votes
What is the closest asteroid to Earth worth mining?
The list doesn't specify a distance to the Earth (the "ground") because this is always changing as the asteroid travels around its orbit. You can get an idea of the asteroid's orbit using the JPL ...
- 2,496
4
votes
How could 99942 Apophis, in 2029, be captured and brought into a low Earth orbit?
Let's toss out some ballpark guesstimates, and go from there.
Using the same figures as other answers: Apophis is estimated to have a mass of $2.7 \cdot 10^{10}$ kg, and needs a Δv change of about ...
- 703
3
votes
Clohessy - Wiltshere equations in electric propulsion
Practically speaking, the CW (Clohessy-Wiltshire) equations https://en.wikipedia.org/wiki/Clohessy-Wiltshire_equations are only useful for a first analytic look at understanding what is happening (...
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Only top scored, non community-wiki answers of a minimum length are eligible