What kind of radiation shielding do you think the Orion capsule has that is so much better than what Apollo had?
As you might expect, the best shielding against gamma radiation is lead, with a tenth-thickness (the thickness required to attenuate exposure by 90%) of about 2 inches. But lead is also very dense and heavy.
Aluminum is less effective, with a tenth-thickness for gamma radiation of about 4 inches.
Hydrogen-containing materials like plastic, food, or water are even less effective, with a tenth-thickness for gamma radiation of about 24 inches. (These types of materials are quite effective in shielding against neutrons, though, which is why they are used around nuclear reactors.)
Both Apollo and Orion use(d) a combination of aluminum (as part of the hull/pressure vessel) and hydrogen-containing materials for shielding. They both have the same limitations. In particular, neither has shielding capable of reducing the radiation by 90%. And they knew just about as much about radiation shielding in the 1960s as they do today.
And no space suit has any significant radiation protection against gamma radiation, during the Apollo era or today. Space suits typically have layers of Mylar, which are better than nothing, but nothing compared to a lead apron…which is not really feasible for a space suit.
That looks reasonable for a time lapse set of images, taken over a period of hours. Remember that’s a very small field of view, filled with stars normally not visible to the naked eye.
The orange suits they wear for takeoff and landing aren’t spacesuits, really, in any sense that block anything burst from the Sun? So they might again be better than nothing, but so would wrapping yourself in mylar.
The worst kind of solar flare is the SEP, which is much rarer, and those will even hit us on Earth with protons. And probably worse, there are hours to days of notice. Not sure how much lead a spacecraft would need to do much, if anything, with that.
I guess all we know more than in the 60’s, there’s no stopping some kinds of radiation. And the exposure badges probably aren’t much different either. Yeah, I somehow thought that they were better protected - and maybe this lead shield is thicker.
This is pretty discouraging for human spaceflight. Unless it’s to Mercury, which is tidally locked to the Sun. Set up shop just below the terminator. Because Venus is right out, and Mars rotates.
Anyways, I want to see whatever they think were meteoroid hits. Anything that is really a space rock that they can see the impact of would be much worse than a blast of radiation if it hit their capsule. I’m skeptical.
No, those orange suits don’t do anything for radiation exposure that is any better than the clothing you are wearing right now.
I have to correct something from my previous post, though. Most radiation exposure is not gamma electromagnetic radiation, but instead charged particles moving at very high speed. Only about 1% of the radiation flux in space is gamma radiation. (It can still be dangerous, though, because it is high energy and can only be easily stopped with dense materials like lead, or very thick less dense material.)
Most radiation in space actually comes from charged particles. There are three main sources:
Cosmic “rays” which are mostly hydrogen nuclei, some helium nuclei, and a small smattering of every other element on the periodic table, all traveling near the speed of light. This radiation is basically constant, and originates mainly from outside our galaxy from distant supernovas and energetic galactic cores.
Solar flares and coronal mass ejections from the sun. This radiation consists mostly of hydrogen nuclei (protons) and is generally unpredictable. It can produce damaging radiation during a solar event.
Trapped charged particles in Earth’s magnetic field in the Van Allen belts.
Most of the particles from all three sources are protons (hydrogen nuclei). For that reason, the best way to shield them is hydrogen-containing materials, like water or plastic. A fairly significant thickness is needed to do much good though, as the tenth-thickness of these materials against cosmic radiation is 50-100 cm, and the shielding necessary to reduce exposure by 50% is about 18 cm.
Interestingly, dense materials like lead can actually cause more harm than good, since cosmic radiation particles are so energetic that they induce secondary showers of radiation from the shielding material itself.
Indeed. It’s a real problem. We don’t often think about Earth’s atmosphere and magnetic field which together provide very effective shielding from space radiation.
OK glitch time, comms between the crew and the recovery team on the boats are supposed to be on a satellite phone channel and capsule can hear the boat but boat can’t hear capsule so Houston is trying to conference-call them.
Because, y’know, being able to switch to one of the Navy’s VHF frequencies is sooo 1960s…
Oh, somehow I had 07 in mind as I turned on NASA TV at 02.
With those parachutes, they could have soft-landed in a parking lot in San Diego. I guess medically-wise, they had to plan for one-by-one extraction. And it’s women and children first.
I always wondered, if the capsule for some reason began sinking, or were dragged down by sinking parachutes, how would the nearby Navy warship rescue them?
I think I see one of those reluctant boats holding a grabber-hook, that being the nautical term.
I’d like to think they planned the contingency for buoyancy sans balloon. I doubt a sub could catch them, but that is what those pressure orange suits are for - they could bail out and just make it harder for the Smithsonian to capture the capsule.