Vjylku

My son is working on a project for science fair that involves a deployable component that will not be heated on a CubeSat. I am trying to help him find data for the skin temperature of a satellite (or the ISS) over a single orbit. Averages and min/maxes are easy to find, but an actual temperature curve of an orbit has been elusive. Does anyone know where this data is available or what the search term we are missing is?

The temperature development of a satellite in LEO depends on a variety of factors. How (quickly) does the satellite rotate, how much is it in eclipse (night), what kind of radiators or internal heat sources exist, etc. When a space mission is being planned, thermal control engineers with dedicated software model the temperature development. What applies for one satellite does not apply for another.

If you want to look at specific examples, NOAA publishes graphs for temperatures for meteorological satellites. For example, you can find the status of NOAA-18 HIRS, in this case for the secondary telescope:

Or the temperature for the NOAA-15 AVHRR motor housing:

All but the top panel show orbital averages.

You can also download the raw data through the NOAA CLASS Archive, but file formats are old and not user friendly (for example, AVHRR data are packed as 13-bit words and the oldest HIRS satellite data headers mix ASCII and EBCDIC fields).

If you browse the various components you will see that they behave quite differently. There is no active cooling on those satellites, only passive cooling. Sometimes components of the satellite are actively heated for decontamination. As you can see, temperature may be widely varying. To know specifically why, you may have to talk to the engineers at NOAA, NASA, EUMETSAT, ESA, or whatever agency controls the satellite of interest.

To find the temperature curve for your cubesat component is non-trivial and any temperature curve you find on the web is unlikely to match the one for your component. If you have access to the right time and skills, you can try to model it. Or you can design your component to handle the extremes / worst case, add some thermistors to it for monitoring purposes, and hope for the best.

This is a supplemental spherical cow answer, followed by links to other questions, answers, and comments there that you may find helpful when working on this project together.

Per ULA's plan for LH2/LOX 2nd stage that can maintain propellant for an extended period of time? the temperature of a spherical object in Sunlight with a uniform surface defined by a visible light reflectivity or albedo $a$ and a thermal infared emissivity $e$ is given by

$$T sim left( frac{(1-a_{vis})}{e_{ir}} frac{I_{Sun}}{4 sigma} right)^{1/4}$$

Most things that are not clean, polished, conductive metal surfaces have a pretty high emissivity, and many infrared thermometers have assume a default value of 0.9 or 0.95 for the object you are measuring when you turn them on. Even things that are white, or even transparent in visible light usually have a pretty high thermal infrared emissivity.

              visible light albedo (reflectivity)

 infrared        a=0.1       a=0.5      a=0.9

emissivity       "dark"     "medium"   "light"

----------     --------    --------    --------

    0.9          279         241         161     paints, glass, anodized metal, PCB (e.g. FR-4)

    0.5          324         279         187

    0.1          484         418         279     polished metal

A quick look shows that for materials where the thermal infrared emissivity and visible light albedos are similar, the equilibrium temperature is about 279 K which is about 6 degrees C, above freezing but a little cooler than the air temperature of a commercial server farm.

For an example worked on an everyday object see this answer where I've cooked a hot dog in space.

Early satellites were coated in high-emissivity, yet mirror-like surfaces by applying a special coating to reflective metal. Perhaps the electronics inside these first satellites could survive some cold exposure, but once they got too hot they'd be irreversibly fried.

@RydgeMulford's authoritative answer to Why are deeper folds better for absorption? explains, some more exotic surfaces to manage temperature.

It is also common for some satellites to have louvres or doors to cover or expose materials of one set of emissivity and albedo with that of a different set. For more on that, see:

• What are these air-vent-like structures on this satellite?


• 
  What are the louver-like structures on the sides of the Mariner 4 probe? was "Why did Mariner 4 look a little like my dad's old slide projector?" but leveler heads prevailed

In comments below this answer I've said:

The top of the linked page in the book Elements of Space Technology by R. X. Meyer it says "If this surface is provided with a high ratio of solar radiation absorptivity to ambient temperature emissivity, control over a wide range of temperatures can be obtained."

That linked page is to Chapter 7 () in Elements of Space Technology for Aerospace Engineers By Rudolf X. Meyer, Rudolph X. Meyer. It may be read in google books, found on the shelves of many university library, or perhaps obtained by inter-library loan. Flipping through a physical book could be fun and inspiring to both of you. Some people (myself included) feel that flipping through good books, and especially library shelves of them is fundamentally superior to just looking at "the internet".

A piece of transparent glass, or one with a mirror second surface would absorb little visible light but radiate well, so it would tend to run fairly cold in space even in sunlight. You can see images of seconds surface mirrors used as "space radiators" in the question and read about them in @Puffin's excellent answer there. Also see more images in What is the function of this array of what looks like mirrors on TESS? and in @CarlosN's excellent answer as well.

Something that was dark and highly absorbing in visible light, but had a low IR emissivity would run quite hot, but I can't think of a standard material that has that property.