Timeline for How would you slow down a large object traveling through space?
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
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| Apr 8, 2021 at 10:24 | comment | added | toolforger | @puppetsock en.wikipedia.org/wiki/Retrorocket#Apollo_program seems to say no retro rockets were used for Earth re-entry. (Doesn't mean I read them correctly, or that the page is correct.) | |
| Apr 8, 2021 at 10:23 | comment | added | toolforger | @puppetsock I couldn't find a reference to the retro-rockets - is there a website that tells us how much speed these rockets took off the capsule? | |
| Apr 7, 2021 at 18:09 | comment | added | puppetsock | Apollo 11 starter their maneuver at 11 km/s. Then they used retro-rockets to slow. Then they hit the atmosphere. | |
| Apr 6, 2021 at 17:22 | comment | added | toolforger | @puppetsock well Apollo already had 11 km/s reentry speed, so that's already beyond what you believe doable - the well-known trick is to put your trajectory into enough of thin atmosphere to slow down sufficiently. Asteroid incoming impacts at roughly 18 km/s (claims Google), so the energy multiplier would be 2.7. I suspect the higher energy makes the re-entry window narrower, but being more shock, deceleration, and heat resistant considerably widens it - now I'm wondering whether there will really be cratering or not. | |
| Apr 6, 2021 at 14:03 | comment | added | puppetsock | Kinetic energy is v-squared. Artillery rounds are less than 1 km/s, usually less than 0.8 km/s though the fastest push 1 km/s. Orbital transfer thus has at least 100 times the energy of an artillery shell of the same mass. How practical do you think impact recovery will be? | |
| Apr 6, 2021 at 7:40 | comment | added | toolforger | @puppetsock Ah ok, I didn't think too much about the difference between moon and interplanetary, and I'm not convinced that aero-braking is useless but I agree you need to do more (slingshot maneuvers with the moon, solar sails, etc.) I'm wondering what would happen if an ingot were just allowed to impact - it wouldn't bury very deep, but would it be shallow enough to be extracted easily, or would it be less expensive to do an in-flight slowdown? | |
| Apr 5, 2021 at 19:59 | comment | added | puppetsock | Wow, this seems to be a difficult point for people. Planetary transfer orbits put the ingots in near-Earth space at a relative speed of 10s of km/s. You cannot use aero-braking for that. The ingots are only in the atmosphere about 10 seconds. You need to slow them down in space before they re-enter. | |
| Mar 31, 2021 at 17:53 | history | edited | toolforger | CC BY-SA 4.0 |
Reworded to make it clearer, give some numbers
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| Mar 30, 2021 at 8:29 | history | answered | toolforger | CC BY-SA 4.0 |