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Feasibility study of a mission to Sedna – Nuclear propulsion and solar sailing

(arxiv.org)
200 points speckx | 3 comments | 01 Jul 25 14:08 UTC | HN request time: 0.689s | source
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chuckledog ◴[01 Jul 25 14:54 UTC] No.44434499[source]▶
https://en.m.wikipedia.org/wiki/Sedna_(dwarf_planet)
replies(1): >>44434770 #
imglorp ◴[01 Jul 25 15:18 UTC] No.44434770[source]▶
They know its radius is ~1000km but interestingly, there is no way to determine its mass without a flyby or other gravitational interaction. I guess you could swag it by using the lunar density, which gives ~~~ 10^22 kg.

https://www.wolframalpha.com/input?i=4.189%C3%9710%5E9+km%5E...

replies(2): >>44434994 #>>44441200 #
1. _joel ◴[01 Jul 25 15:37 UTC] No.44434994[source]▶
Wouldn't it's composition be of more ice and rock (like pluto), therefore lower density than the moon?
replies(1): >>44436080 #
2. sapiogram ◴[01 Jul 25 17:18 UTC] No.44436080[source]▶
That's a reasonable assumption, but given Sedna's unusual orbit, its origin could also be quite different from Pluto's.
replies(1): >>44436905 #
3. benbayard ◴[01 Jul 25 18:45 UTC] No.44436905[source]▶
In the wikipedia post you are replying to has the chemical composition of the surface of the planet, obviously we can't know what is beneath that, but to me, indicates this is closer to Pluto than it is to our Moon.

> Detailed spectroscopic analysis has revealed Sedna's surface to be a mixture of the solid ices of water (H2O),[15] carbon dioxide (CO2), and ethane (C2H6), along with occasional sedimentary deposits of methane (CH4)-derived,[16] vividly reddish-colored organic tholins,[15] a surface chemical makeup somewhat similar to those of other trans-Neptunian objects.[17]