Timeline for How to escape from a small super-earth?
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Nov 4, 2016 at 16:20 | comment | added | dmckee --- ex-moderator kitten | I know I'm late but it occurs to mean that we don't need to burn twice as fast. The Saturn V took off at 8 gees acceleration, which means that it's accent relative the ground was 7 gees. On the hypothetical planet that would be 6 gees. Our replacement first stage only need to burn about 17% faster to get the same progress relative the ground. Upper stages need a slightly large improvement, but still not double. | |
| Oct 2, 2016 at 13:23 | comment | added | UTF-8 | "Some more weight"? You probably almost need to double the dry mass of the stages to get twice the thrust. The first stage of the Saturn V had a dry mass of 131 t which already is very close to its payload to LEO. Doubling the dry mass of the second stage already exceeds the original payload in extra mass. If we neglect the extra mass of the third stage, this means, you're now about half way to LEO, nowhere close to escaping, and used all of your fuel up. | |
| Oct 2, 2016 at 2:11 | comment | added | John Dallman | Yup, you're right: the rockets need to burn fuel twice as fast (aka develop twice the thrust), which costs some more weight. Chemical launching is not impossible, but it may well be impractically expensive. | |
| Oct 1, 2016 at 20:20 | comment | added | UTF-8 | This would be true if you could burn the fuel twice as fast as the Saturn V burns it because you have to account for the temporally longer pull of gravity on what remains of the rocket which costs you energy. I'll take a more detailed look onto this later. PS: You're defeating the purpose of the setting (no (purely) chemical launches possible). :D ;-) | |
| Oct 1, 2016 at 20:07 | comment | added | dmckee --- ex-moderator kitten | A designed for purpose system should be able to do better (with the same tech) than putting an Athena || on a Saturn V, but it's a cute proof of concept. | |
| Oct 1, 2016 at 19:57 | history | answered | John Dallman | CC BY-SA 3.0 |