Mercury: Difference between revisions
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There is no atmosphere. The core is molten from 1/3rd of the way in down to the centre. | There is no atmosphere. The core is molten from 1/3rd of the way in down to the centre. | ||
The planet rotates three times for each two orbits. One 88 day orbit is 88*2/3 = 58.6 day year. A hot day in sunlight is 700K, a cold night is 100K. The bottoms of polar craters are a constant night temperature, there is ice. The solar radiation density ("flux") is 7 times that on Earth. | The planet is tidally locked and rotates three times for each two orbits. One 88 day orbit is 88*2/3 = 58.6 day year. A hot day in sunlight is 700K, a cold night is 100K. The bottoms of polar craters are a constant night temperature, there is ice. The solar radiation density ("flux") is 7 times that on Earth. | ||
Rockets get faster as they fall toward the sun when going from Earth to Mercury. The only way to slow down is to carry fuel for braking. Then you need more fuel to land the fridge from orbit. You don't need to slow into an orbit if you just aim at the planet and land. Orbiting gives you a big sideways speed which you need to get rid of before you touch the surface. | Rockets get faster as they fall toward the sun when going from Earth to Mercury. The only way to slow down is to carry fuel for braking. Then you need more fuel to land the fridge from orbit. You don't need to slow into an orbit if you just aim at the planet and land. Orbiting gives you a big sideways speed which you need to get rid of before you touch the surface. | ||
Revision as of 09:33, 6 January 2020
There is no atmosphere. The core is molten from 1/3rd of the way in down to the centre.
The planet is tidally locked and rotates three times for each two orbits. One 88 day orbit is 88*2/3 = 58.6 day year. A hot day in sunlight is 700K, a cold night is 100K. The bottoms of polar craters are a constant night temperature, there is ice. The solar radiation density ("flux") is 7 times that on Earth.
Rockets get faster as they fall toward the sun when going from Earth to Mercury. The only way to slow down is to carry fuel for braking. Then you need more fuel to land the fridge from orbit. You don't need to slow into an orbit if you just aim at the planet and land. Orbiting gives you a big sideways speed which you need to get rid of before you touch the surface.
The surface is made of rocks. The surface would melt if heated more with concentrated sunlight or with electricity. Trapping gas needs cold. Electrolysis might separate the elements.
Propping one of the 1km mirrors near the surface would keep the day temperature down nearer the cold night temperature. There is no atmosphere to carry the heat into the shaded area. Blocking the view sideways would also reduce infrared heat radiating from the sunlit surface.