chiruochiba

chiruochiba t1_iqy8ne6 wrote

This is way off topic, but...

For spacecraft operation longterm in a void, heat dissipation is a serious logistical issue. Engines, circuitry, etc, generate heat that builds up without any atmospheric particles to transfer it to. Surfaces that absorb energy directly from sunlight can get too hot. For this reason, NASA's designs specifically called for white exterior surfaces on their shuttles.

More detail about that here:

Spacecraft Subsystems Part 3 ‒ Fundamentals of Thermal Control (PDF)

>Thermal control surfaces can be any surface that is used for spacecraft thermal control to include coatings, paints, and finishes. Most internal and external spacecraft components have a thermal control surface to help control its emittance and/or absorptance properties. The performance of these surfaces are characterized by the ratio of absorptivity to emissivity, α / ε, which are characteristics of heat transfer by radiation. For example, white paint has a low ratio and therefore is used as a heat emitter. Ratios greater than 1.0, like blank paint, will get hot when exposed to sunlight.

>Black and white paints are the most common color. Most paints have a high emittance, with varying absorptance and electrical conductivity properties. Black paints have the following characteristic: α ≈ ε ≈ 1.0, which is close to thermal equilibrium. This means that most of the heat that is absorbed is then emitted. This makes black paint an effectively neutral color, thermally. Because of this and its performance ratio of >1.0 as previously discussed, most internal spacecraft components are painted black. Most external spacecraft surfaces are painted white to minimize solar energy absorptance.

>Thermal control surfaces are also a key part of other thermal control methods to be described in this section, which include multi-layer insulation (MLI) blankets and radiators. Aluminized Kapton is commonly used for the MLI blanket external layer. Surfaces with a performance ratio of less than 0.4, like white paints or optical solar reflectors (OSRs), make them effective radiators.

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chiruochiba t1_iqtscic wrote

From the scientific article:

>Females start to breed at 2–3 years of age (Özdemir et al., 2012), which means that 10–15 generations have passed since the Chornobyl accident.

2022-1986=36 years

Divide by 2.5, which is the approximate number of years it takes for a newborn female to reach maturity = about 15 generations of new reproductive females.

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