2 ms·
That's good calculation there, but the number we're concerned with is the amount of ∆v that the spacecraft has to generate itself. If you just get close enough
by logfromblammo 9y ago
That's good calculation there, but the number we're concerned with is the amount of ∆v that the spacecraft has to generate itself. If you just get close enough to the sun, a spacecraft could use the solar wind and solar magnetic field to shed more velocity, until it is close enough to aerobrake in the sun's atmosphere.
Once you're out in the Oort cloud on the way out, you can't exactly deploy a solar sail to get another push (unless you make it impractically large).
- JumpCrisscross 9y agoThe outermost layer of the Sun ends at 0.1 AU [1]. To put that in perspective, Mercury orbits at between 0.3 and 0.5 AU [2]. (It costs about 13 km / s to get to Mercury exiting from LEO.) It's much cheaper to fling things out of the Solar System than into the Sun. [1] https://en.m.wikipedia.org/wiki/Sun#Atmosphere https://en.m.wikipedia.org/wiki/Sun#Atmosphere [2] https://en.wikipedia.org/wiki/Mercury_(planet) https://en.wikipedia.org/wiki/Mercury_(planet)
- logfromblammo 9y agoAgain, you are thinking in terms of propellant carried up from Earth. Thrust available to a spacecraft using a solar sail is a function of distance to the sun. The sail is a fixed cost, but it may be presumed to degrade over time. It has no propellant that costs additional money to launch. If you go in, the ever decreasing efficiency of the sail is offset by the greater available energy from the solar wind, and you may still be able to complete the mission (more slowly) with a damaged sail. Your available thrust increases with every kilometer closer to the sun. If you go out, the decreasing efficiency of the sail compounds with the lesser total energy available to the sail, and if the sail is damaged, you may never reach escape velocity at all. You will never have more thrust than the instant the sail deploys.