Question about Orion protection from radiation

a reply to: DJW001

But there are countless satellites using microchips that went over the vab.
So the concern expressed is about technological failures that can affect humans rather than the equipment itself. Sometimes I wonder if this tech that's been promoted is really a big improvement if it's less reliable than stuff 50 years old.

Thank you for the reply tho, at least you mentioned some more specific changes I can look at.

Lets not forget about the type of memory that Apollo used.
Core memory.

It uses tiny magnetic toroids (rings), the cores, through which wires are threaded to write and read information. Each core represents one bit of information.

It is also relatively unaffected by EMP and radiation.

originally posted by: Mastronaut
a reply to: onebigmonkey

But we should have quite good data from the satellites and all the missions we have in space, some of which surely have high tech components. Most of my interest is why passing through the belts should be an unresolved concern looking at the wording of the scientist. Not that I think it's settled science or easy, but there is no other reference to something like very high cost or something like that which could justify having to still "resolve" the problem before sending humans through it.

True, up to a point, but you still have to 'man-rate' a spacecraft to make sure that it will do what you want it to do and behave the way you think it will.

I understand the vulnerabilities, however I can't find any statistics about failures for current electronics in space so I can't understand the magnitude of the problem. I found this but it's old ('96) and evaluates a hundred cases from 74 to 94. I think this isn't even applicable to today's tech and I'd expect NASA to have far better than consumer tech which is probably already more sophisticated than what's in that paper.

I think you made the point right there: it's historic data. I am also no expert in these matters, but it seems to me that if no matter how superior your tech is, if you don't test it you don't know what will happen to it. The best way to test is to put it through the kind of things it will need to survive and see what happens.

I think it's harder to shield the crew rather than the devices, at least the internal ones, so it's either about external sensors or I can't explain that specific sentence from the NASA guy and I don't think it was just poor wording. The problem I have is that everything is just generalized and I can't find some more in-depth explaination of the studies they are doing for the issue presented.

p.s. I want to be clear that I don't see any conspiracy here, it's more about what new component in this case is MORE subsceptible, or if it not about components at all.

Articles that tend to make it onto mainstream news sites, and popular science pages, tend to be 'watered down' (for want of a better phrase) for a general audience. It isn't just that things may be more susceptible it's that the fancy electronics will be exposed to things for much longer. Some of those electronics will be dedicated to making sure that the crew stays alive!

originally posted by: Mastronaut I also already read most of the info about van Allen belts, but this post is more about what's in Orion that puts at a higher stake the lives of the crew members compared to the Apollo ones? Because that's what seems to suggest the wording of that specific phrase.

(Emphasis added)

Most items have already been hit upon:

- Anticipated trajectories will go through thick areas of the VABs, whereas Apollo only skimmed through thin edges.

- The duration of Orion missions will be much longer than Apollo, increasing the overall exposure in general, and increasing the likelyhood of being out there when a solar flare occurs.

- Modern electronics are much more susceptable to stray voltages induced by radiation impingment.

I will add one more, and this relates directly to the part of your post that I underlined above:

- NASA is much more sensitive to the amount of radiation that they want their astronauts exposed to than they were in the 1960's. Remember that at the time Apollo was conceived and designed, the US, Soviet Union, Britain, France and (from 1964 on) China were all still doing atmospheric nuclear testing. Ordinary citizens were getting doses - sometimes heavy (my Dad, who worked at Oak Ridge in the early '60s, had thyroid cancer before he was 35). For military personnel (which most of the astronauts were) radiation exposure was just one of the risks - like crashing an airplane. When compared to the magnitude of the project on which they were working, radiation was simply a matter of playing the odds. Alan Shepard was the first American in space, and went to the Moon on Apollo 14. He died of leukemia in 1998. Maybe his illness was caused by radation exposure, maybe it wasn't. He didn't care - He flew his missions and is in the history books
Since then, the culture has changed. People have had basements & cellars for thousands of years, but now they install radon detectors because it freaks them out that this colorless, odorless, naturally-occuring radioactive gas might be seeping-in through the rock. In our litginous society, everyone wants to assign blame for whatever happens, and everyone wants to avoid blame when something does happen.

(deleted several long, rambling paragraphs)

One more thing about radiation shielding: We know how to do it. It's easy - Find the right material and pile it on. The trick with shielding a manned spacecraft is that - as with any spacecraft, satellite or probe ever built - the one overwhelming, overriding design consideration is weight (OK, mass). If it's too heavy, it can't do the mission. If you have so much mass in the shielding, you might not have enough of something else (crew, instruments, sensors or whatever) to make the mission worthwhile.

I think the emphasis on Orion's shielding is about finding inovative new ways of creating light-weight shielding that can do the job for less mass. Flying both the shielding and sensitive electronics in the VAB is an easy way of doing a "worst-case" test.

originally posted by: Mastronaut

But there are countless satellites using microchips that went over the vab.

Most of those satellites aren't actually powered on while going through the VABs. They only get fully peered up once they reach their target orbits. The electronics are less susceptible to radiation when they aren't powered up and running. Orion has to function all the way through the VABs.

In my very humble opinion, the current concerns for safety of astronauts passing the VABs are largely due to the modern concepts of Health&Safety. We can't just stick human beings in a tin can atop a modified ICBM rocket and hope it works, like we did in the 60s and 70s.

Also, and just off the top of my head, Orion missions will be to more distant targets than the Moon, and as such might require more complex orbits and transitions, keeping the spacecraft in the VABs for a longer period of time.

Thanks everyone for the replies, I still think that the concerns expressed in the video are maybe a way to sell it to the public (hinting to conspiracies) and at the same time a preemptive action in case of failed experiments or cut of funds that could delay the first mission.

@nataylor
I read about that, but I don't understand exactly why it can't be done the same to a capsule. After all, you only need life sustaining devices active for the time it takes to go from the inner to the edge of the outer belt.

originally posted by: Mastronaut
@nataylor
I read about that, but I don't understand exactly why it can't be done the same to a capsule. After all, you only need life sustaining devices active for the time it takes to go from the inner to the edge of the outer belt.

its not so much that it cant be done, its more to do with making it reliable.

the electronics can PROBABLY survive the trip through a couple of times, but they want to GUARANTEE that it will continue to work as intended after many traverses.
and unlike all other space crafts that need to traverse the VAB, Orion is intended for man-rated re-usability.

originally posted by: Mastronaut
Hello, I have a question regarding a video we already watched a few times (I guess), and it was already posted here but I couldn't find what I was looking for because the thread seemed to go the way of lunar landing hoax vs real. I don't have a strong opinion about this subject, but more importantly I frankly don't care much at the moment.

I read many things, mainstream and not, about the radiation in the van Allen belts and in this article from huffpost there is a link that allegedly explains everything (an old page from year 2000). In fact it doesn't explain anything about what is said in the video even tho the article seems to give a hint that the link is going to explain what new technology would be extremely endangered by the belts.

Also the article is misleading in the interpretation of the wording. The guy in the video clearly states "through this region of space", which is ofc not what the article state, i.e. that exposure for longer time in deep space is what he meant.

So what I would like to ask is: what is the new equipment that would be subject to additional concerns?
I would assume that 40 years of studies on materials, radiation control and shielding would make passing through the belts a far easier achievement than it was in '69, but it seems not the case.
Maybe is it due to the ship design? Or orbital path needed? Or is it just poor wording from the NASA guy (and in this case has it been reworded/retracted)?

Thanks in advance

p.s. please don't turn this question in a hoax vs not debate, it's about vulnerable tech of today that wasn't present in the old days).

Orion is supposed to be capable of deep space missions. So the idea is to test the radiation protection by sending it trough the belt.

I assume they could have sent the capsule to Mars instead. But that would be probably a much more expensive test flight.

From EFT1 ( December 5, 2014) fact sheet:

Twice during the mission, Orion will fly through the Van Allen Radiation Belt, a dense radiation field of highly energetic charged particles surrounding Earth. This exposure will help the team understand and mitigate radiation exposure, and to develop protective solutions before the first crewed mission.

originally posted by: Mastronaut

originally posted by: swanne
a reply to: Mastronaut

I thought Apollo avoided the Van Allen Belt by simply passing by the pole?

Word is, mister Van Allen himself helped figure out Apollo's trajectory to minimize radiation exposure.

Well yes, as I read here it was a matter of staying under the belts for the acceleration path and then passing through them very fast. Why is this not possible with Orion, and why isn't it possible to just have a "polar exit", because unless I'm reading it wrong every Apollo mission went through them.
Is it a military concern to do polar orbits or is it expensive or inefficient?

Apollo using a conventional chemical rocket to leave low earth orbit. The thrust that provided the TLI burn was able to raise the orbit to one that intercepted the moon in just a few minutes, so an off-plane burn that intercepted the moon without forcing the spacecraft to pass through the most intense part of the belts was entirely doable. Apollo did not pass through the same region of space as Orion EFT-1. Using SPENVIS, here is the dose expected for an Apollo astronaut sitting inside an Apollo spacecraft with about 7-8 g/cm^2 areal density on the trajectory taken by Apollo to the moon:
h.dropcanvas.com...
That dose isn't dangerous at all. Here is the expected dose if you were to send Apollo astronauts in an Apollo command module on the same trajectory as Orion EFT-1's final orbit:
h.dropcanvas.com...
Nearly 30 rads of radiation in far less time, just one orbit (essentially an acute and sudden dose). At that dose you are approaching the threshold at which you may start to exhibit mild symptoms of radiation poisoning according to the CDC:

"Mild symptoms may be observed with doses as low as 0.3 Gy or 30 rads."
www.bt.cdc.gov...

Still won't kill you, but it might just make you sick if you fly Orion EFT-1's trajectory with the older Apollo capsule. As to your question of why they can't just do that in the future with Orion, the stated plan is to use solar electric propulsion to get out of earth orbit efficiently (but slowly).
www.nasa.gov...
www.rocket.com...
This is very different from Apollo. They need far more delta-V than Apollo, and to get there and back with a reasonable number of launches they're talking about using high isp methods of propulsion like Hall effect thrusters. They're very efficient but very low thrust. There is no real way to avoid the most intense part of the Van Allen belts with such a propulsion system if you're traveling to a destination within the plane of the solar system such as Mars. You can use an off-plane trajectory like Apollo if you want, but the apogee point still has to be within the plane of the ecliptic which means you're going to be passing close to and through the regions where the Van Allen belts are most intense - you can't raise the apogee fast enough to avoid it with solar electric propulsion.

While such a trajectory would be unsafe for humans in an Apollo capsule, the electronics on Apollo were less susceptible to radiation though. Orion's flight computer is not a custom job purpose-built to withstand radiation, it's adapted directly from a jet airliner computer with radiation hardening added on.
www.informationweek.com...
That needed to be validated before we put people in it. It's one thing if your unmanned satellite's computer has hiccups, it's quite another if the computer that drives human life support craps the bed in the middle of the night because of radiation. A mars crew will be many light minutes from mission control, so they're going to be on their own for the most part when it comes to acute emergencies.

a reply to: ngchunter

Thank you very much ngc, it was a very informative post and I think it answer all my questions.