Ultimate Steve Posted February 1 Share Posted February 1 (edited) Surprised there is no thread for this yet. 2024 YR4 is a newly discovered asteroid that flew by Earth in December of 2024, will fly by Earth again in December 2028, and and will have a particularly close approach with Earth in 2032, with a chance of impact initially estimated at 1 in 110 on January 23, 2025, which has risen to 1 in 59 as of today, February 1, 2025. If it impacts, it is estimated to have as much energy as 8 megatons of TNT. https://en.wikipedia.org/wiki/2024_YR4 It is likely that further telescope observations will decrease this probability to zero, but I find it interesting as the approach in 2028 gives us a perfect opportunity for redirection if one is needed, especially as we have just done a practice run with the DART mission. We have the technology to stick, say, a 10 ton mass in its path, and the asteroid's relative velocity should do the rest if my envelope math is correct, leading to a change in orbital period and a miss in 2032. Edited February 1 by Ultimate Steve Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted February 1 Share Posted February 1 Even sending a probe to rendezvous with it and study it in 2028 could function as a gravity tractor to slowly move it out of harm’s way Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted February 1 Author Share Posted February 1 2 minutes ago, StrandedonEarth said: Even sending a probe to rendezvous with it and study it in 2028 could function as a gravity tractor to slowly move it out of harm’s way I redid my math with much more detail and it seems that any reasonably sized spacecraft (a few hundred kilos and up) will likely be more than sufficient to redirect it kinetically, assuming my math is right. A gravity tractor would have to cancel out a lot of relative velocity ( I think it would have to escape Earth with a v infinity of somewhere near 13km/s but I could be wrong) to stay around the asteroid. While I think that's a much more interesting and scientifically valuable mission profile, I think a kinetic impactor would involve significantly less risk. Ideally we would send multiple. Quote Link to comment Share on other sites More sharing options...
GuessingEveryDay Posted February 1 Share Posted February 1 They've said that it's estimated to be 40 to 100 meters wide, and the meteor that made the Barringer Crater was 50 meters wide. However the Barringer Crater's meteor was pretty much just iron and nickel. It will be interesting to see what this one is made out of. Also, wouldn't be better if we let it crash into somewhere in the Saharan Desert? Not only does it remove a possible risk of another flyby and it actually impacting somewhere important, we would also be able to compare calculations of simulated impacts and the event itself. The crater would also be a really cool place for geologists to visit. Quote Link to comment Share on other sites More sharing options...
darthgently Posted February 1 Share Posted February 1 11 minutes ago, GuessingEveryDay said: Also, wouldn't be better if we let it crash into somewhere in the Saharan Desert? What could go wrong? Quote Link to comment Share on other sites More sharing options...
GuessingEveryDay Posted February 1 Share Posted February 1 Well, to start, it's better than steering it into Point Nemo (where we'll be putting ISS there anyways), the entirety of the Sahara Desert is on one tectonic plate, so no risk of earthquakes caused by it. Also it would provide a way for us to check calculations. Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted February 2 Author Share Posted February 2 Impact probability is back down to 1 in 71. Quote Link to comment Share on other sites More sharing options...
darthgently Posted February 2 Share Posted February 2 (edited) 18 hours ago, GuessingEveryDay said: Well, to start, it's better than steering it into Point Nemo (where we'll be putting ISS there anyways), the entirety of the Sahara Desert is on one tectonic plate, so no risk of earthquakes caused by it. Also it would provide a way for us to check calculations. I just think that would not be the best goal for a first time test of a sizable asteroid redirect. Probably better to redirect it to a body other than Earth until we get a few more redirects under our belt, lol. IOW, first just make it miss the Earth and secondarily stop it somewhere else. A multi step process Edited February 2 by darthgently Quote Link to comment Share on other sites More sharing options...
Superpluto126 Posted February 2 Share Posted February 2 This is concerning when you look at the fact it has enough energy to wipe out a small city, and its path runs over Columbia, Parts of South America and the African Coast. If it does impact, there is a reasonable chance its either over the Atlantic, or over someplace important. Quote Link to comment Share on other sites More sharing options...
darthgently Posted February 2 Share Posted February 2 28 minutes ago, Superpluto126 said: This is concerning when you look at the fact it has enough energy to wipe out a small city, and its path runs over Columbia, Parts of South America and the African Coast. If it does impact, there is a reasonable chance its either over the Atlantic, or over someplace important. No matter where it hit it could be extremely damaging. Tsunamis, dust cloud, raining debris etc. If it looks like it will hit Earth redirect as wide as we can into the the orbit that gives us with the most breathing room or into a Mars or the Moon colliding orbit should that sliver of an opportunity appear. On Mars or Moon we could have our cake and eat it too as eventually we could explore/exploit its remains as well as having removed an earth crossing asteroid from our watch list Quote Link to comment Share on other sites More sharing options...
magnemoe Posted February 2 Share Posted February 2 1 hour ago, darthgently said: No matter where it hit it could be extremely damaging. Tsunamis, dust cloud, raining debris etc. If it looks like it will hit Earth redirect as wide as we can into the the orbit that gives us with the most breathing room or into a Mars or the Moon colliding orbit should that sliver of an opportunity appear. On Mars or Moon we could have our cake and eat it too as eventually we could explore/exploit its remains as well as having removed an earth crossing asteroid from our watch list Except that none metallic asteroids tend to break up and air burst who is nice unless it burst late over an populated area. Danger rise exponentially with size and this is small. How hard to capture? KSP player want to know. Quote Link to comment Share on other sites More sharing options...
K^2 Posted February 3 Share Posted February 3 The estimates I've seen put it under 10MT, because relative velocity isn't all that high. It's not great, and the latest track places rather populated parts of India as a potential (though, less likely) point of impact, so this could still turn out to be the worst disaster in recorded history. But the far more likely outcome is an impact in an ocean or less populated parts of Africa, which would result in comparatively minor destruction. Still, if we can redirect it, it's better than letting it hit the Earth. So worth investing resources into it. My understanding is that the 2028 fly-by will be when we'll get a much better idea if it's a risk for 2032 or not, and should give us a bit of time to prepare a response. Oh, and even if we chose a point of impact, a 10MT explosion is still going to have climate impacts, and our precision on redirect is not going to be great. It's far, far safer to just cause it to miss. Yes, that leaves a small chance of it becoming a problem again in the future, but at that point, it's just as likely as any random rock. Quote Link to comment Share on other sites More sharing options...
Exoscientist Posted just now Share Posted just now Scott Manley did a calculation that the required impactor would be relatively small size so that a Falcon 9 could launch it. The problem is the asteroid’s velocity and position are not precisely known so the impactor’s needed speed and direction are not precisely known. Because of uncertainty in position and velocity might want high payload to get large number of impactors with range of trajectories to give high likelihood of correct impact velocity and direction. If using Starlink satellite-like impactors, can use onboard thrusters to do fine adjustments on approach. From Grok: Query: How many Starlink satellites would the SpaceX Starship be able to carry? Response: The SpaceX Starship is designed to carry significantly more Starlink satellites than the current Falcon 9 rocket. According to information available on the web, Starship is expected to carry: •V2 Starlink satellites: Around 400 satellites per launch, as mentioned in SpaceX's plans for deploying the second-generation Starlink satellites. •V3 Starlink satellites: Plans indicate that Starship could launch over 100 V3 Starlink satellites in a single flight, with each launch adding about 60 Tbps of capacity to the Starlink network. These numbers reflect the increased payload capacity of Starship compared to the Falcon 9, which has been launching batches of 50 to 60 V1 satellites or fewer for the larger V2 Mini satellites. Bob Clark Quote Link to comment Share on other sites More sharing options...
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