Mercury - Revision history

John at 11:32, 24 January 2020

2020-01-24T11:32:33Z

← Older revision		Revision as of 11:32, 24 January 2020
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	The surface is made of [https://phys.org/news/2012-09-characterizing-surface-composition-mercury.html rocks]. The surface would melt if heated more with concentrated sunlight or with electricity. Trapping gas needs cold. Electrolysis might separate the elements.		The surface is made of [https://phys.org/news/2012-09-characterizing-surface-composition-mercury.html 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. Working in a trench above 70N or 70S will keep the ~~nots~~ cool all the time while allowing daytime power generation at the surface - that's what NASA proposed ten years ago in their shelved lander paper (a copy is on the forum). Keeping the bots out of the sunlight is probably a good idea.		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. Working in a trench above 70N or 70S will keep the bots cool all the time while allowing daytime power generation at the surface - that's what NASA proposed ten years ago in their shelved lander paper (a copy is on the forum). Keeping the bots out of the sunlight is probably a good idea.

	== How to soft land on Mercury ==		== How to soft land on Mercury ==

John: /* How to soft land on Mercury */

2020-01-16T11:28:16Z

How to soft land on Mercury

← Older revision		Revision as of 11:28, 16 January 2020
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	The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine or fins seems is too high and too wobbly to sit on all the time after landing on bare ground. Every lunar lander has kept its engines attached underneath. The lander can't easily reorient itself if it falls over, that's why airbagging was rejected in NASA's proposal along with the extra weight.		The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine or fins seems is too high and too wobbly to sit on all the time after landing on bare ground. Every lunar lander has kept its engines attached underneath. The lander can't easily reorient itself if it falls over, that's why airbagging was rejected in NASA's proposal along with the extra weight.

	[https://en.wikipedia.org/wiki/Lidar LIDAR hazard avoidance, distance to land] is active all the way down. It has to see past the engine while the engine is burning. SpaceX's stage recovery to the barge has worked this out already. LIDAR can find a hole and land in it to stay out of the sun if the lander is within 20° of a pole.		[https://en.wikipedia.org/wiki/Lidar LIDAR hazard avoidance, distance to land] is active all the way down. It has to see past the engine while the engine is burning. SpaceX's stage recovery to the barge has worked this out already though they partly rely on aerofoils and we have just one engine and no idea how to gimbal it. LIDAR can find a hole and land in it to stay out of the sun if the lander is within 20° of a pole.

John: /* How to soft land on Mercury */

2020-01-16T11:26:30Z

How to soft land on Mercury

← Older revision		Revision as of 11:26, 16 January 2020
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	*Apollo used a contact probe and fell from 1.6m		*Apollo used a contact probe and fell from 1.6m

	The direct approach velocity at the landing site is perhaps 2km/s so that's the least speed you have to get rid of. There's no air no swerving no parachutes no heatshield.		The direct approach velocity at the landing site is perhaps 2km/s so that's the least speed you have to get rid of. There's no air so no swerving no parachutes no heatshield.

	The ground mission would fail if the communications channels with Earth all fail. We might prefer to leave several communications satellites in orbit but I think the price would rise. Direct radio from the surface will reach any 30m dish we might have access to.		The ground mission would fail if the communications channels with Earth all fail. We might prefer to leave several communications satellites in orbit but I think the price would rise. Direct radio from the surface will reach any 30m dish we might have access to.
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	Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.		Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.

	The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine is too high and too wobbly to sit on all the time after landing. Every lunar lander has kept its engines attached underneath. The lander can't reorient itself if it falls over, that's why airbagging was rejected in NASA's proposal.		The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine or fins seems is too high and too wobbly to sit on all the time after landing on bare ground. Every lunar lander has kept its engines attached underneath. The lander can't easily reorient itself if it falls over, that's why airbagging was rejected in NASA's proposal along with the extra weight.

	LIDAR hazard avoidance, distance to land, is active all the way down. It has to see past the engine while the engine is burning. SpaceX's stage recovery to the barge has worked this out already.		[https://en.wikipedia.org/wiki/Lidar LIDAR hazard avoidance, distance to land] is active all the way down. It has to see past the engine while the engine is burning. SpaceX's stage recovery to the barge has worked this out already. LIDAR can find a hole and land in it to stay out of the sun if the lander is within 20° of a pole.

John: /* How to soft land on Mercury */

2020-01-16T09:46:11Z

How to soft land on Mercury

← Older revision		Revision as of 09:46, 16 January 2020
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	The ground mission would fail if the communications channels with Earth all fail. We might prefer to leave several communications satellites in orbit but I think the price would rise. Direct radio from the surface will reach any 30m dish we might have access to.		The ground mission would fail if the communications channels with Earth all fail. We might prefer to leave several communications satellites in orbit but I think the price would rise. Direct radio from the surface will reach any 30m dish we might have access to.
	*program updates		*program updates from Earth
	*progress reports		*progress reports to Earth

	Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.		Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.

John: /* How to soft land on Mercury */

2020-01-16T09:44:35Z

How to soft land on Mercury

← Older revision		Revision as of 09:44, 16 January 2020
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	Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.		Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.

	The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine is too high and too wobbly to sit on all the time after landing.		The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine is too high and too wobbly to sit on all the time after landing. Every lunar lander has kept its engines attached underneath. The lander can't reorient itself if it falls over, that's why airbagging was rejected in NASA's proposal.

	LIDAR hazard avoidance, distance to land, is active all the way down. It has to see past the engine while the engine is burning.		LIDAR hazard avoidance, distance to land, is active all the way down. It has to see past the engine while the engine is burning. SpaceX's stage recovery to the barge has worked this out already.

John: /* How to soft land on Mercury */

2020-01-16T09:38:09Z

How to soft land on Mercury

← Older revision		Revision as of 09:38, 16 January 2020
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	Nobody has yet, but they have on the moon which is similar because it also has no atmosphere.		Nobody has yet, but they have on the moon which is similar because it also has no atmosphere.
			*Luna 9 and 13 airbagged
	*Luna 9 and 13 airbagged.		*Surveyor 1 fell 3.4m onto a crumple zone
	*Surveyor 1 fell 3.4m onto a crumple zone.		*Surveyor 3 was 292kg and 700kg fuel
	*Surveyor 3 was 292kg and 700kg fuel.		*Apollo used a contact probe and fell from 1.6m
	*Apollo used a contact probe and fell from 1.6m.

	The direct approach velocity at the landing site is perhaps 2km/s so that's the least speed you have to get rid of. There's no air no swerving no parachutes no heatshield.		The direct approach velocity at the landing site is perhaps 2km/s so that's the least speed you have to get rid of. There's no air no swerving no parachutes no heatshield.

John: /* How to soft land on Mercury */

2020-01-16T09:37:28Z

How to soft land on Mercury

← Older revision		Revision as of 09:37, 16 January 2020
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	== How to soft land on Mercury ==		== How to soft land on Mercury ==

	Nobody has yet, but they have on the moon which also has no atmosphere.		Nobody has yet, but they have on the moon which is similar because it also has no atmosphere.

	*Luna 9 and 13 airbagged.		*Luna 9 and 13 airbagged.
	*Surveyor 1 fell 3.4m onto a crumple zone. Apollo used a contact probe and fell from 1.6m~~. Surveyor 3 was 292kg and 700kg fuel~~.		*Surveyor 1 fell 3.4m onto a crumple zone.
			*Surveyor 3 was 292kg and 700kg fuel.
			*Apollo used a contact probe and fell from 1.6m.

	The direct approach velocity at the landing site is perhaps 2km/s so that's the least speed you have to get rid of. There's no air no swerving no parachutes no heatshield.		The direct approach velocity at the landing site is perhaps 2km/s so that's the least speed you have to get rid of. There's no air no swerving no parachutes no heatshield.

John: /* How to soft land on Mercury */

2020-01-16T09:36:12Z

How to soft land on Mercury

← Older revision		Revision as of 09:36, 16 January 2020
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	The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine is too high and too wobbly to sit on all the time after landing.		The lander is strapped to a brake engine. How does it get off before it touches down? The brake engine is too high and too wobbly to sit on all the time after landing.

	LIDAR hazard avoidance, distance to land, is on all the way down. It has to see past the engine while the engine is burning.		LIDAR hazard avoidance, distance to land, is active all the way down. It has to see past the engine while the engine is burning.

John: /* How to soft land on Mercury */

2020-01-16T09:35:51Z

How to soft land on Mercury

← Older revision		Revision as of 09:35, 16 January 2020
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	*program updates		*program updates
	*progress reports		*progress reports

	Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.		Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.

John: /* How to soft land on Mercury */

2020-01-16T09:35:13Z

How to soft land on Mercury

← Older revision		Revision as of 09:35, 16 January 2020
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	== How to soft land on Mercury ==		== How to soft land on Mercury ==

	Nobody has yet, but they have on the moon.		Nobody has yet, but they have on the moon which also has no atmosphere.

	*Luna 9 and 13 airbagged.		*Luna 9 and 13 airbagged.
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	The ground mission would fail if the communications channels with Earth all fail. We might prefer to leave several communications satellites in orbit but I think the price would rise. Direct radio from the surface will reach any 30m dish we might have access to.		The ground mission would fail if the communications channels with Earth all fail. We might prefer to leave several communications satellites in orbit but I think the price would rise. Direct radio from the surface will reach any 30m dish we might have access to.
			*program updates
			*progress reports
	Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.		Slingshot braking has to get the mission to meet Mercury in its orbit with as low a relative velocity as possible, before diving for the ground and needing a chemical brake. Can it slow exactly the right amount in a sun graze and get to zero velocity on a right-angle approach (or catch up from behind and below) to Mercury orbit from the sun side? Or do these brakes only work around moving planets in orbit.