Editing Talk:2906: Earth
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Does anybody know what is a typical reentry burn, for instance, when a capsule leaves the ISS? I wrote "some hundreds m/s" but it might be less than that. If the original orbit is very low, even a tiny reduction will lower the perigee enough to intersect the atmosphere. [[User:Rps|Rps]] ([[User talk:Rps|talk]]) 18:57, 18 March 2024 (UTC) | Does anybody know what is a typical reentry burn, for instance, when a capsule leaves the ISS? I wrote "some hundreds m/s" but it might be less than that. If the original orbit is very low, even a tiny reduction will lower the perigee enough to intersect the atmosphere. [[User:Rps|Rps]] ([[User talk:Rps|talk]]) 18:57, 18 March 2024 (UTC) | ||
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:Most treatments I see of the respective Delta-V Budgets basically deal with having to overcome the atmospheric and gravity deficits upon launch ''to'' LEO, which don't easily apply/discount in reverse. Also the delta-v needed betwixt low-LEO and high-LEO (or roughly encompassing the difference between current space-stations and a Hubble servicing mission) is almost a full km/s (either way), so you might need to add that to the much smaller(?) final bit of atmosphere-hitting adjustment, whereupon you hopefully are now slowing down entirely passively. (Rather than bouncing off...) | :Most treatments I see of the respective Delta-V Budgets basically deal with having to overcome the atmospheric and gravity deficits upon launch ''to'' LEO, which don't easily apply/discount in reverse. Also the delta-v needed betwixt low-LEO and high-LEO (or roughly encompassing the difference between current space-stations and a Hubble servicing mission) is almost a full km/s (either way), so you might need to add that to the much smaller(?) final bit of atmosphere-hitting adjustment, whereupon you hopefully are now slowing down entirely passively. (Rather than bouncing off...) | ||
:If you can afford to wait, though, being at ISS heights will bring you down with ''zero'' (active) delta-v. There being tenuous atmosphere, already, that actually requires maintenance boosts every now and then to keep it up there. So maybe you need to consider it much as you do with a launch profile (over-powered rocket first-stage gets you over the atmospheric 'hump' quicker, and requires less total delta-v expendes for the same eventual mission). But the ultimate solution (entirely hand-brake your orbit, just fall straight down from space itself) is also not practical or necessary. | :If you can afford to wait, though, being at ISS heights will bring you down with ''zero'' (active) delta-v. There being tenuous atmosphere, already, that actually requires maintenance boosts every now and then to keep it up there. So maybe you need to consider it much as you do with a launch profile (over-powered rocket first-stage gets you over the atmospheric 'hump' quicker, and requires less total delta-v expendes for the same eventual mission). But the ultimate solution (entirely hand-brake your orbit, just fall straight down from space itself) is also not practical or necessary. | ||
:All in all, your "some hundreds m/s" is probably not far wrong. | :All in all, your "some hundreds m/s" is probably not far wrong. | ||
:Perhaps chase down the Crew Dragon operating manual, as a current example, if you want to put such actual figure(s) as used. Not sure how public that info is, but there are a lot of armchair experts out there that ''particularly'' reverse engineer vague SpaceX release-info into solid-looking figures that Musk then confirms "sound about right" if he responds to their assessments. If the usual suspects haven't crunched this number, then I'd be surprised. [[Special:Contributions/172.69.195.38|172.69.195.38]] 05:24, 19 March 2024 (UTC) | :Perhaps chase down the Crew Dragon operating manual, as a current example, if you want to put such actual figure(s) as used. Not sure how public that info is, but there are a lot of armchair experts out there that ''particularly'' reverse engineer vague SpaceX release-info into solid-looking figures that Musk then confirms "sound about right" if he responds to their assessments. If the usual suspects haven't crunched this number, then I'd be surprised. [[Special:Contributions/172.69.195.38|172.69.195.38]] 05:24, 19 March 2024 (UTC) | ||
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My reading: The original plan for Voyager 1 was it, after LEO to complete its mission and to be destroyed by burning in the atmosphere. So, all the spectacular discoveries of Voyager 1, including the Pale Blue Dot, are unintentional results of Cara’s miscalculations. Contrary to popular opinion, the Carl’svcoworkers are deeply disappointed that Voyager didn’t burn. [[Special:Contributions/162.158.60.145|162.158.60.145]] 12:43, 19 March 2024 (UTC) | My reading: The original plan for Voyager 1 was it, after LEO to complete its mission and to be destroyed by burning in the atmosphere. So, all the spectacular discoveries of Voyager 1, including the Pale Blue Dot, are unintentional results of Cara’s miscalculations. Contrary to popular opinion, the Carl’svcoworkers are deeply disappointed that Voyager didn’t burn. [[Special:Contributions/162.158.60.145|162.158.60.145]] 12:43, 19 March 2024 (UTC) |