8
$\begingroup$

According to Wikipedia, the E-sail consumes about 540 W (https://en.wikipedia.org/wiki/Electric_sail#Fast_missions_to_planet_Uranus)

But this consumption is continuous, and considering an engineering point of view, how viable is this?

$\endgroup$

2 Answers 2

3
$\begingroup$

The original concept was conceptually simpler Original Solar Sail

An artistic rendering of the current concept shows as spinning spacecraft with radial tethers again with an electron gun ensuring the sail has a positive charge. With this configuration there are also auxiliary thruster units at the tether tips. This more advanced version would allow the direction of thrust to be controlled. There are also new concepts such as negatively charging the sail with an ion gun. This paper talks about proposing a Uranus mission including a power budget.

enter image description here

At 1 au, the 0.5 N E-sail needs nominally 540 W of electric power to keep its tethers charged (Janhunen et al., 2013). The electric power requirement of the E-sail scales as $\frac{1}{r^2}$ i.e. in the same way as the illumination of solar panels (Janhunen et al., 2010; Toivanen and Janhunen, 2009) although the thrust scales as 1/r (Janhunen et al., 2010). Thus, if enough solar panels are used to power the E-sail at 1 au, the same panel area is sufficient also at larger solar distances, excluding a small constant power needed by E-sail control systems. During cruise, the E-sail spin plane is typically inlined by at most 45$^o$ with the solar direction so that the illumination of the solar panels is reduced by a factor of 0:7. This is a conservative estimate because significant inclination occurs early in the mission where solar illumination is strong. If we require that the total power is 1 kW at 1 au (at 451 orientation) and assuming 20% overall efficiency for the panels, then the required panel area is 5.35 $m^2$. This panel area fits easily inside the 4 m diameter disk configuration which was discussed above. It does not fit on a 2 m diameter disk area, however, so that in the 2 m diameter cylinder solution which was discussed above, one has to use deployable solar panels.

$\endgroup$
6
  • 1
    $\begingroup$ What is the source of the quote? $\endgroup$ Sep 12, 2022 at 1:36
  • $\begingroup$ do you have any paper or report about positively charging using an ion gun? I can't imagine how an ion gun could positively charge tethers $\endgroup$ Sep 12, 2022 at 1:54
  • 1
    $\begingroup$ The quote is from the link. ‘A comprehensive review of Electric Solar Wind Concept and its applications’ Bassetto et al. Progress in Aerospace , January 2022 $\endgroup$
    – UVphoton
    Sep 12, 2022 at 12:09
  • $\begingroup$ @RicardoCasimiro my typo, I meant negatively charging the sail, which is harder with an ion gun emitting positive ions. $\endgroup$
    – UVphoton
    Sep 12, 2022 at 12:11
  • 1
    $\begingroup$ @OrganicMarble sorry the other link within the paper doi.org/10.1016/j.pss.2014.08.004 $\endgroup$
    – UVphoton
    Sep 12, 2022 at 14:20
0
$\begingroup$

I found my answer in the power source of Voyager 2, link: https://en.wikipedia.org/wiki/MHW-RTG

Basically at launch it provides 470 W (and decay with time), so I think is viable and reliable to use it in electric sail.

I hope it can be useful for others in the future :)

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.