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Hot answers tagged near-earth-object

51

No, it's entirely unrealistic. The Earth is very large by the standards of what you deal with in day to day life -- it's about 13 million meters in diameter. Satellites are typically only a few meters across, and the additional debris bits can be much smaller. The artist here is depicting satellites as being hundreds of thousands of meters in size. There is ...

36

The "actual data" is that for every one of their dots, there is probably a real debris fragment, the mix of satellites/rocket bodies etc is probably broadly right, and so on. However, the picture is also labelled with "size of debris exaggerated as compared to the Earth". If you look at those "satellites", each one is sized as ...

19

NEOs are mostly found as dots in images taken by various telescopes, often those of amateurs (as in not paid, nothing about skill or equipment). By taken repeated images days apart moving dots can be picked out against the static background stars and an orbit plotted. Then that orbit is matched against known objects, and used to either add a new object to ...

18

We cannot depict the space junk to scale. Neither the human vision, nor modern imaging technology can have both Earth and whatever human-made orbiting object visible at the same scale, without having the small object reduced to profoundly sub-pixel size. The space junk is not alone in this limitation. One can open e.g. FlightRadar24 with e.g. Europe on the ...

14

It would take vastly more $\Delta V$ to get it to a low-Earth orbit. The targets selected are close enough to Earth's orbit about the Sun that it only takes around $200\,\mathrm{m/s}$ to get it into a distant retrograde orbit about the Moon. To get the thing to a low Earth orbit would be around $3\,\mathrm{km/s}$. The tyranny of the rocket equation makes ...

14

Definitely - it could be ejected. But Earth would only play a minor role. Starman now counts as a Near Earth Object, being any object crossing Earth's orbit. Any such object is occasionally in Earth's vicinity, when they cross our orbit while we are nearby. The orbits of such objects have now been modeled over time periods of millions of years. From ...

13

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 wording: ...specific asteroids and/or their asteroid orbit type... As discussed in Have there been any documented mini-moons since 2006 RH120?, "mini-moons&...

10

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 end up as considered dangerous: We discover it. There may be an asteroid bound for Earth at this moment, we just haven't seen it yet. This is fairly straight ...

7

That's a one trillion dollars question! Proximity of near-Earth flybys of asteroids is largely irrelevant when it comes to feasibility of matching their orbit and rendezvousing with them, what is more important is their hyperbolic excess velocity with respect to Earth, and how much delta-v is needed to do that. There are many Athen, Apollo and Amor groups of ...

7

Asteroid 2010 TK7 is called an Earth Trojan. But it's orbit isn't as long lived as the Jupiter Trojans. According to Wikipedia: 2010 TK7's orbit has a chaotic character, making long-range predictions difficult. Prior to A.D. 500, it may have been oscillating about the L5 Lagrangian point (60 degrees behind Earth), before jumping to L4 via L3. Short-term ...

6

Safety of our blue planet. Eventually, gravity anomalies would cause even a perfectly orbited object (a moonlet?) to preces and hit the body it orbits around. Since orbiting an asteroid means reducing large fraction of its momentum to bring it closer to celestials it naturally orbits (NASA's plans involve capturing a near-Earth asteroid, or NEO, as part of ...

6

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 motion shown in the gif, so as the asteroid rotates, all of these instruments will be able to have full coverage of it. OSIRIS-REx Visible and Infrared Spectrometer ...

5

As far as I know, only NASA (since you asked for the agency) through its High Definition Earth Viewing (HDEV) Experiment gives the live coverage of the Earth from the ISS. It might not be up for all the time and they sometimes switch to previously recorded videos in case of technical problems but this is only source I know available in the public domain. ...

5

Possibly the earliest documented mini-moon was the one associated with the 1913 Great Meteor Procession. After 2006 RH120, that you mentioned, another was identified on October 3, 2015 and designated WT1190F. It impacted Earth on November 13, 2015. It was probably space debris, and not natural. There's only one other potential candidate that I know of so ...

5

The real issue here is how much rocket propellant you have to spend to get to the location in question. In one way, asteroids are easier to get to due to the fact that landing on the Moon takes a lot of velocity change. On the other hand, an asteroid flying through the Earth-Moon system is going really fast, so catching up with it is going to take a lot of ...

5

Your encounter must by definition occur somewhere around the MOID line, if you do not consider to significantly change the trajectory. A solution can be obtained using Keplerian analysis, but that is only an approximation, due to the hard-to-restrict three body nature of the problem. If I understand your question correctly, you want a higher degree of ...

5

To add to the other answers, Wikipedia has another page listing objects at Lagrangian points, and for Sun–Earth L4 (SEL4) it currently lists: Asteroid 2010 TK7 is the first discovered "tadpole" orbit companion to Earth, orbiting L4 with a mean distance of about one astronomical unit. STEREO A (Solar TErrestrial RElations Observatory – Ahead) made ...

5

The largest human space object in space is the International Space Station, with the largest dimension at some 100 meters. Lets depict that as a 2x2 pixel on a very good display (400 Pixels Per Inch as in iPhones). The actual size - on the display - is about 0.1 by 0.1 millimeters The ISS "flies" at some 400 km - that's 4,000 times the size of the ...

4

The threat posed by such near-Earth objects can be illustrated by the most famous extinction-level asteroid, the one responsible for the Chixclub crater of the Yucatán Peninsula. This bolide, at least 10 km wide, is almost universally credited with the demise of the dinosaurs. Defensive measures against such objects entirely depends upon finding it in time ...

4

We want to find NEOs that are inside Earth's orbit, like Atens, and telescopes don't like looking close to the Sun. So the more inside the orbit of the Earth you can get, the more new NEOs you will find without having to look at the Sun. Ideally you'd like a NEOCAM near the orbit of Venus. Then you'd be able to catch 'em all. But at E-S L1, you'll find most ...

4

I don't have the time right now to post a comprehensive answer, so I'll do a provisional one with some resources that might help you out. At some point I will might edit this into a full answer. Here's a couple of papers that you'll be interested to read: https://dspace.mit.edu/handle/1721.1/73467 https://planet4589.org/jcm/pubs/sci/papers/2018/Taylor18.pdf ...

3

There are estimated to be around 1 million Near Earth Objects (NEOs) of around in the same size as 2017 VL2, of which around 1% are known (see Rusty's Planetary Defense 6-part series). It's only much larger asteroids which are better tracked: we're estimated to know well over 90% of the NEOs larger than 1 km, and are aiming to get up to 90% of the 140 m+ ...

3

The trick isn't to mine them when they are close, necessarily. Asteroids are cheaper to get to than the Moon because the Moon has quite a bit of gravity. If you aim correctly, you can avoid all of the loss of rocket fuel associated with gravity. Where it is doesn't matter that much (So long as it is in a nearby orbit. The bottom line is, an Asteroid mining ...

3

These objects aren't of particular interest at the moment, as we would have a hard enough time reaching Near Earth asteroids. However, they offer some potential benefits in the future, namely: They could provide orbital resources for Mars for fuel and such. They could assist in transforming Mars (Impacts could provide useful resources, for instance.) ...

2

There is a large amount of dust, and one known asteroid. From Wikipedia: The Sun–Earth L4 and L5 points lie 60° ahead of and 60° behind the Earth as it orbits the Sun. The regions around these points contain interplanetary dust and at least one asteroid, 2010 TK7, detected October 2010 by WISE and announced July 2011. The Earth–Moon L4 and L5 ...

2

Multiple reasons exist. Weapon of Mass Destruction Any large body in orbit is a potential weapon of mass destruction. Drop a 20-ton rock from orbit, and it may not survive, but if you do it right, it creates a crater some 100m across. While NASA is not planning on using deadfall artillery, the possibility is a political issue. Ownership and access Legally, ...

2

WT1190F orbited the Earth during the time it was observed. There were a number of varying observations that were made over it's lifetime. Wikipedia shows the lifetime at 3 different years, each with a wildly different orbit. Due to frequent passes by the Moon, as well as the Yarkovsky effect and pertubations of solar radiation, even a small difference could ...

2

For an unrelated purpose, I retrieved the Mission Requirements Document (OSIRIS-REx-RQMT-0001) for OSIRIS-REx. It details the minimum performance requirements for the mission. We can look at requirements section 3.3: Bennu Global Properties, Chemistry & Minerology Mapping Requirements. Here are the requirments: OSIRIS‐REx shall image > 80% of the ...

2

For years, wide field infrared orbital telescopes have been touted as the best way to complete a survey of NEO objects and give a greater warning time on potential close approaches. Astronsapper's Plantetary Society article talks about this partially. For years, proposals have been put forth to build these orbiting telescopes, but there is not a strong ...

2

Partial answer to get things moving. While so far I haven't found an asteroid proper that was first observed by radar, there are at least several examples of objects that were first discovered optically but that were subsequently determined to be binary asteroids or have minor-planet moons of their own. However, checking the binary asteroids "87 Sylvia, ...

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