Re: [Spaceships] Habitat observations
 

I'm not sure where you're getting that. The rules in SS5 take account only of the number of systems (excluding low-mass ones like Cargo bays or Habitats) that are protecting the crewed areas.

No argument there. The current rules are a gameable abstraction. I suppose it's rare for a tabletop game to even care about radiation.

Re: [Spaceships] Habitat observations
 

The rules for number of dense modules still only multiplies dDR and divides by 100 for Cosmic Radiation. It makes more advanced armors more effective when only mass matters. Rock is just as good or bad at stopping GCR as super tough diamondoid, not 1/20th.

Re: [Spaceships] Habitat observations
 

When nearly every space game ignores economics and often Relativity and Newton, a pesky thing like near unstoppable GCR seems almost like inconsequential nitpicking.

Re: [Spaceships] Habitat observations
 

There is no mention of DR in that section. The Radiation PF is based solely on the number of massive systems, and does not change for higher or lower tech levels. Now, perhaps the specific values given can be disputed, but the system is using the same method as you are so should at least serve as a solid starting point.

Re: [Spaceships] Habitat observations
 

Oh crud. I misremembered. I apologize for any confusion.

According to my layman's research, its PF 400 or 4 against GCR is equivalent to our atmosphere. That isn't true as 4 would only cut the dose from open space around 700 mSV to 175 far above our 0.3 mSV or 2 to 3 total background radiation. Off by around 100 if we secretly switched Sv for Gurps Rads.

Re: [Spaceships] Habitat observations
 

No worries. I actually started to get nervous that I'd missed something myself. Wouldn't be the first time.

What you've calculated so far sounds convincing, but I'm just a layman too. It may be that Spaceships is using different assumptions about structural strength / density, or that the way our atmosphere absorbs / deflects radiation is more complicated that simple mass.

The issue of astronauts not surviving a round trip to the moon may be more an issue of the radiation sickness rules being unrealistic, or breaking down when dealing with a low dosage over a long period instead of a single large dose.

Re: [Spaceships] Habitat observations
 

Things like OSHA rules use a linear model for radiation safety and the GURPS rules do also. In reality there seems to be a threshold under which it doesn't have an effect. Otherwise places like Denver or people like aircraft crews that spend lots of time with less atmosphere above them would have lots more cancers.

For Apollo part of the radiation safety was launch during low solar flare periods and hope there are no major ones for a week.

Re: [Spaceships] Habitat observations
 

I think their cancer rates are higher, but all things considered cancer is pretty darn rare for an individual over a single year. We tend to measure them in occurrences per lifetime.

Re: [Spaceships] Habitat observations
 

Here's a map showing the rate of fatal cancers per 100,000 lifetimes, for men in the USA, by county. Here is the corresponding map for women. Cancer rates in the Rockies are if anything significantly lower than elsewhere.

Re: [Spaceships] Habitat observations
 

Well GCR are a minor part of background radiation, especially in the U.S. Around 1/10 of all non-profession related radiation.
Radon exposure seems to be the largest section in the U.S. I bet it would take an in depth statistical analysis to determine if the minor differences in ground elevation and subsequent GCR exposure matter for cancer rates.

But recent research seems to point toward medium to high energy GCR posing half the biological danger as initially thought. They tend to pass through too fast to have much effect or destroy the entire cell rather than damage the D.N.A. risking cancer.
For gurps, this means needing only half as much armor to get earth ground levels, a very nice feature for spaceships where ever gram matters.
Remove radon from the environment and you might get lower cancer rates than ours.