GiveMeABreak wrote: ↑20 Jul 2019, 13:47
X Rays in the Van Allen belts (2 hours exposure) - so much for the camera film,
Did you watch the Curious Droid video I linked to ?
There are no X Rays (electromagnetic radiation) in the Van Allen belts - the van allen belts are ionizing radiation consisting of charged particles ejected from the sun by the solar wind. (Eg unbound protons and electrons) The same particles that generate the northern lights.
When ionizing radiation hits certain materials it can generate some secondary radition in the form of xrays however the production of these xrays is highly dependent on the type of material it hits, so by choosing outer layers that produce minimal secondary xray generation and then inner layers that absorb them it's not a major issue.
In addition to that they didn't fly through the strongest parts of them which are around the equator anyway - they flew up "over" them in the polar regions. As the earth is already tilted at 24 degrees relative to the orbital plane of the moon you don't want to be leaving the earth in line with the equator anyway.
Van allen belts are not an issue unless you blindly built your spacecraft out of the wrong materials and flew out through the strongest parts of them at equatorial lattitudes. Watch the video for a better explanation than I can give.
no dust on the lander, yet massively powerful rockets,
Three reasons for that.
1) The moon has no atmosphere at all. Any dust thrown up would not linger in the air then coat the outside of the lander as it settled like it would on earth. It would literally fall back to the ground at the same speed as a dropped bowling ball. So it might move around a bit but it would fall quickly to the ground again.
2) With no atmospheric pressure pushing in on it the rocket exhaust will not form a focused directional plume like you see when a rocket launches on earth. In vacuum conditions a rocket exhaust expands unconstrained in all directions once it leaves the nozzle so even if the nozzle is pointing down the exhaust will be flowing out over at least a 180 degree plane - eg right out to at least 90 degrees from the direction of thrust.
So there isn't a focused blast of exhaust pointing straight down - there is a large pressure wave spread over an entire 180 degree plane, so the intensity at the ground directly below the nozzle is far, far less than it would be with an atmosphere to squeeze and focus it towards the ground. Put simply a rocket landing on a body without an atmosphere will not disturb the ground nearly as much as landing on earth even for the same gravity. And with a reduced gravity the thrust required to land is proportionally reduced. (By a factor of 6 on the moon)
To see the effect in action, watch one of the many Space X Falcon 9 launches - at ground level the rocket plume is narrow, vertical, and almost the length of the entire rocket. As it reaches the upper atmosphere it expands into an umbrella shape where it is almost reaching out at right angles as if an umbrella was attached to the bottom of the rocket.
3) The landing motor on the lunar lander was not a "massively powerful rocket" by any stretch of the imagination. The lunar lander by the time it had used up most of its decent fuel weighed about 8 metric tons. Gravity on the moon is about 1/6th earth so on the moon that would only weigh 1.3 tons - less than what the average car today weighs on earth. So to hover above the moon as it came to land would only require 1.3 tons of thrust.
Compare that the the Merlin 1D engine in the Falcon 9 rocket (a much smaller rocket than the Saturn 5) which has 62 tons of thrust, and has 9 engines for a total of 558 tons of thrust.
The F1 engine used on the Saturn 5 had 670 tons of thrust per engine - with 5 engines that's 3,350 tons of thrust. The 1.3 tons of thrust from the lander engine is a pipsqueak by comparison. The lunar lander really was a tiny thing compared to the rocket that launched it.