The threat of radiation is severely overblown.

NASA is overpaying for underperforming "hardened" hardware that performs no better than non-hardened. You can see this yourself with the mars helicopter ingenuity.

If you are desperate for extra safety then just include multiple computers, literally what spacex does.

▲

adrian_b 4 hours ago | parent | next [-]

The threat of radiation is not overblown at all.

The errors caused by radiation are extremely frequent and you definitely must guard against them, otherwise anything will fail immediately in space.

However that does not necessarily require hardware measures. It may be more efficient if instead of a slow antique CPU with hardware redundancy you use a fast modern CPU, even if it is more sensitive to radiation and even when it lacks hardware redundancy, but you do each computation several times, verifying that every time you get the same result, and if possible you use different algorithms or verification methods, to be able to detect some permanent errors.

This is what the Mars helicopter did. If it had used standard smartphone software, the helicopter would have failed instantly.

▲

gambiting 3 hours ago | parent [-]

>>The errors caused by radiation are extremely frequent and you definitely must guard against them, otherwise anything will fail immediately in space.

I asked this in another thread but I will repeat it here - how come that their bog standard iPhones that they use for taking pictures with are still operating fine then? If like you said, "anything will fail immediately" - doesn't sound like that's the case? They have electronic watches with no radiation hardening, they have regular laptops with no radiation hardening.....I'm not saying that it's not a problem, but it definitely doesn't seem to be in the area of "immediately failing in space" if you don't have that.

▲

samus 3 hours ago | parent | next [-]

None of these devices are mission-critical. Worst case they have to be restarted; then they are fine again and the world moves on.

	▲	gambiting an hour ago \| parent [-]
		Yes, but that wasn't the question. OP said anything that's not radiation hardened will fail immediately - to which I ask ok, what about all the stuff they brought up with them which doesn't seem to be instantly failing.

▲

zimpenfish 3 hours ago | parent | prev [-]

(I have no expertise or knowledge of this area but...)

tl;dr: people need (heavy) radiation shielding, cpus et al can live without it

I'd imagine their bog standard iPhones and watches are generally in parts of the craft which have more radiation protection than others and, further, that it's probably only the parts where people are going to be that get that protection (due to weight savings, etc.) and if you can mitigate radiation problems by using a $30 CPU instead of a $2 CPU and save $100K of weight on radiation shielding on the CPU compartment, that's a no-brainer.

▲

samus 3 hours ago | parent | prev | next [-]

Unshielded circuits are basically radiation detectors. Even here on planet Earth bitflips are an underappreciated source of unreproducible bugs.

A bit flip in an index variable, a pointers or in native code can send the CPU on a wild goose chase around memory.

To add insult to injury, applications like browsers use JITs, which generate and execute large amounts of native code on the fly, making them even more vulnerable for this kind of fault.

The same issue arises from overclocking, inconsistent power sources, and from damaged RAM cells, but those problem sources can presumably be dismissed on a vehicle with pristine, well-made hardware during a short hop to the moon and back.

https://news.ycombinator.com/item?id=47252971

▲

cubefox 3 hours ago | parent | prev [-]

> If you are desperate for extra safety then just include multiple computers, literally what spacex does.

That does nothing to protect the human body from the radiation damage.

Talking about microchips is a distraction.

▲

spacedoutman 2 hours ago | parent [-]

Depending what model you subscribe too, small dose radiation can be healthy for you.

	▲	cubefox an hour ago \| parent [-]
		The radiation in space is not "small dose". It's firmly established that it is quite bad for human health.