4 ms·
Not a problem. The L1 point is where the gravitational pull of the Sun is balanced by the gravitational pull of the planet plus the centrifugal force; if you m
by cperciva 10y ago
Not a problem. The L1 point is where the gravitational pull of the Sun is balanced by the gravitational pull of the planet plus the centrifugal force; if you move slightly closer to the sun, its gravity will balance planetary gravity, centrifugal force, and the pressure on the sail.
- credit_guy 10y agoI think this would happen if L1 was a stable lagrange point, like L4 and L5. That's not the case though, L1, L2 and L3 are unstable. To put it differently, ignoring the centrifugal force, at L1 the gravitational pull of Mars is equal to the gravitational pull of the Sun; when you move the sail towards Mars, the pull towards Mars increases, the one towards the Sun decreases, and the resultant points in the same direction as the pressure on the sail (i.e. towards Mars). Nothing is balanced, in the end the sail falls towards Mars.
- kirrent 10y agoNo, the fact that it's not stable isn't what's being talked about. It's merely the fact that an additional force from the solar wind would act to shift the equilibrium point of L1 slightly towards the sun.
- credit_guy 10y agoMakes sense. Thanks for clarifying.