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The potential trick for dealing with this is sundiving with a solar sail. That is, you set out of earth orbit for Venus, and while there, do a gravity assist t

The potential trick for dealing with this is sundiving with a solar sail. That is, you set out of earth orbit for Venus, and while there, do a gravity assist to drop your perihelion very low. Then, you use the sail to brake (lower aphelion) the whole way in, and as the thrust you get from the sail goes up the closer you get to the sun, by the time you reach your perihelion you have sufficient thrust to be in complete control of your orbit, with infinite Δv. Then you can match your aphelion to Mercury at your leisure, and arrive with a slow constant raise of your perihelion to make entering low orbit very cheap. The math works out so far as thrust is concerned, even with relatively conservative solar sail designs. The bigger question is how much risk does unpredicted solar activity cause. (On the other hand, you might have the ability to just dodge any you encounter... Solar sails very close to the sun operate more like cartoon spaceships than any other real spacecraft.)

lmilcin 5y ago
Solar sails might be acceptable for unmanned probes, but for an actual manned mission so close to Sun you need a huge vessel, which would require proportionately gigantic sail. While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun. It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet, you can have as many of them in flight as you want (and your budget allows). It could actually be interesting to see if it would be possible to have a fleet of these vessels constantly moving between Earth/Mercury, taking cargo by randezvous at Earth's orbit and dropping it off at Mercury's orbit to come back for more cargo. Kind of light-powered conveyor belt.
- Tuna-Fish 5y ago
  > for an actual manned mission so close to Sun you need a huge vessel, which would require proportionately gigantic sail. It will be big, but a lot less so than you'd think. Solar sails need to be a huge proportion of the mass of the vessel they are moving if you are near earth. However, the thrust provided by the sail scales by 1/(distance to sun)². Near Mercury's perihelion, solar sails are stronger than they are near earth's orbit by a factor of ~10. But that's not where it ends. The plan calls for sundiving, or going <1 million km from the surface of the sun, where sails have tens of thousands of times the thrust they have near earth. > While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun. Solar wind is charged, which means it's just extra thrust with the right kind of sail. > It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet This would actually be a lot faster than going to Mercury with a traditional Hohmann transfer, assuming you leave earth with a burn towards Venus (you could also slowboat with the sail there, but that would probably take years). The route is circuitous, but the speeds would be much, much higher.
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lmilcin 5y ago

Solar sails might be acceptable for unmanned probes, but for an actual manned mission so close to Sun you need a huge vessel, which would require proportionately gigantic sail. While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun. It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet, you can have as many of them in flight as you want (and your budget allows). It could actually be interesting to see if it would be possible to have a fleet of these vessels constantly moving between Earth/Mercury, taking cargo by randezvous at Earth's orbit and dropping it off at Mercury's orbit to come back for more cargo. Kind of light-powered conveyor belt.

Tuna-Fish 5y ago
> for an actual manned mission so close to Sun you need a huge vessel, which would require proportionately gigantic sail. It will be big, but a lot less so than you'd think. Solar sails need to be a huge proportion of the mass of the vessel they are moving if you are near earth. However, the thrust provided by the sail scales by 1/(distance to sun)². Near Mercury's perihelion, solar sails are stronger than they are near earth's orbit by a factor of ~10. But that's not where it ends. The plan calls for sundiving, or going <1 million km from the surface of the sun, where sails have tens of thousands of times the thrust they have near earth. > While you can deal easily with heat by reflecting the light, you need to contend with a lot of shielding necessary to deal with solar winds that are much more stronger and frequent so close to the sun. Solar wind is charged, which means it's just extra thrust with the right kind of sail. > It might be possible to run a train of supply missions this way, I would have to check the math but I am too lazy today to do it:) IN general it does not matter a lot how long it takes for a supply mission to reach the planet This would actually be a lot faster than going to Mercury with a traditional Hohmann transfer, assuming you leave earth with a burn towards Venus (you could also slowboat with the sail there, but that would probably take years). The route is circuitous, but the speeds would be much, much higher.
- deleted 5y ago
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