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One might employ a solar sail/parachute. When you get near Mercury, you’d have more than 4 times the force on the sail too.
by state_less 5y ago
One might employ a solar sail/parachute. When you get near Mercury, you’d have more than 4 times the force on the sail too.
- samplatt 5y agoHow would the sun push a solar sail towards the sun?
- giantrobot 5y agoYou sail at night. It's not rocket science.
- fuzzylightbulb 5y agoObviously it is sail science and therefore boat stuff. This should be a joint NASA + NOAA mission.
- deleted 5y ago[deleted]
- tomatotomato37 5y agoOrbital manuevers are kinda counter-intuitive in that you when you want to get closer/farther from whatever you're orbiting you actually want to change the speed at which you're orbiting. So in the case of solar sails, you would tack in a retrograde direction.
- Teever 5y agohttps://en.m.wikipedia.org/wiki/Tacking_(sailing) https://en.m.wikipedia.org/wiki/Tacking_(sailing)
- JohnJamesRambo 5y agoBut to tack you need a centerboard or keel in the water to push against. I can't think of a way to do this in space.
- Teever 5y agoThat's a really good point. Here's what I was able to find about the matter from a brief search. https://space.stackexchange.com/questions/370/can-you-tack-against-the-sun-using-a-solar-sail https://space.stackexchange.com/questions/370/can-you-tack-a...
- ravel-bar-foo 5y agoOn Earth you need a keel to oppose the force on the sail, which has a component in the direction of the wind. In orbit, the equivalent radial force is mostly perpendicular to the direction of motion, and so does very little work. Radial forces in orbit are much less efficient at changing orbital parameters than the equivalent axial (prograde/retrograde) acceleration. Moreover, if your orbit is roughly circular the applied force mostly averages out over each orbit.
- berkes 5y agoTacking not only uses a keel, it also uses the shape of a sail and Bernoulli's principle [0] to get the perpendicular and forward force. I'm not versed in solar-particle-physics, but I doubt the Bernoulli's principle applies to solar particles. [0] https://en.wikipedia.org/wiki/Bernoulli%27s_principle https://en.wikipedia.org/wiki/Bernoulli%27s_principle
- perl4ever 5y ago"For outward bound trajectories, the sail force vector is oriented forward of the Sun line, which increases orbital energy and angular momentum, resulting in the craft moving farther from the Sun. For inward trajectories, the sail force vector is oriented behind the Sun line, which decreases orbital energy and angular momentum, resulting in the craft moving in toward the Sun. It is worth noting that only the Sun's gravity pulls the craft toward the Sun—there is no analog to a sailboat's tacking to windward. To change orbital inclination, the force vector is turned out of the plane of the velocity vector." https://en.wikipedia.org/wiki/Solar_sail https://en.wikipedia.org/wiki/Solar_sail
- Sharlin 5y agoIn space you practically never ever want to accelerate radially away or towards whatever you're orbiting. Counterintuitively, on average that doesn't get your closer to or farther from the primary, it only serves to change the eccentricity of your orbit (raising the apoapsis and lowering the periapsis or vice versa). What you want to do is accelerate either parallel or antiparallel to your orbital velocity (ie. tangent to the orbit). With a solar sail you do this simply by orienting the sail at a roughly 45° angle relative to the sun, allowing you to either accelerate or decelerate depending on which way you reflect the photons (the resulting force will be normal to the sail so in practice solar sailing is more complicated than that, but you get the point).
- eru 5y agoIf only our solar sailing boats could have a keel.