In The Century of Space Science, edited by J.A. Bleeker, Johannes Geiss, M. Huber, viewed in Google books I ran across the following text and images.

Both satellites are quite stylish looking and have very pronounced alternating white and black stripes.

Presumably the satellites would not be exposed until they are in space when the fairing or nose cone can open, so they would be too far away to see clearly in a telescope so that rotation or tumbling would be visible.

Question: Why were Europe's first few satellites so stylish? Why did they have very pronounced alternating white and black stripes, and had Vanguard-like antennas, but not its shiny reflective metallic finish1,2.

From pages 52 and 53:

France's Astérix was a 42 kg test satellite

The fruits of these investments were soon to be seen. On 26 November 1965, a Diamant rocket rose from the Hammaguir launch pad and placed into orbit the first French satellite, significantly called Astérix. France thus became the third space power and confirmed its claim for an independent role in this important strategic field.

Astérix was a 42 kg test satellite whose role was to confirm the rocket’s ability to place it into orbit. Ten days later, on 6 December 1965, an American Scout rocket launched France’s first scientific satellite, FR-1. This satellite, weighing 60 kg, had been developed by CNES and carried instruments for studying ionization irregularities in the ionosphere and the magnetosphere. It was launched from Vandenberg and placed into a near-circular orbit.

Italy's San Marco-1 satellite

Broglio was quick to react to NASA’s offer of collaboration in space research. In 1962, Italy and the USA signed an agreement for the so-called ‘San Marco’ project, and two eyars later, on 15 December 1964, the first Italian satellite, San Marco-1, was launched by a Scout rocket from Wallops Island. It was a sphere with a diameter of 66 cm and weighed no less than 115 kg. Built by the University of Rome’s Centro di Ricerche Aerospaziali under the direction of Broglio, this was the first all-European satellite to circle the Earth. A second San Marco satellite was launched by Broglio’s group in 1967 from a platform anchored in the Indian Ocean off the coast of Kenya, and the programme continued in the following decade.

1Puzzler: Is this a Sputnik?

2This BBC photo does not show a replica of Vanguard-1, what might it be?

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    $\begingroup$ Possibly related: space.stackexchange.com/q/37554/6944 $\endgroup$ – Organic Marble Sep 4 '19 at 14:40
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    $\begingroup$ Related fact: Tracking of space objects is often done with optical telescopes example, this was partially done to prevent unidentified space objects from triggering missile alerts. When SACI-1 failed first contact, is was possible to identify that the panels had opened and the umbilical cable had been properly cut. $\endgroup$ – Mefitico Oct 24 '19 at 20:22
  • $\begingroup$ @Mefitico those links are compelling, but how are they related to this question post exactly? I'm missing the context. These may also be of interest: What would be a “big picture” understanding of how the orbits of Earth satellites are monitored? and also Is there a satellite that tracks other satellites? $\endgroup$ – uhoh Oct 25 '19 at 0:41
  • $\begingroup$ @uhoh I had a gut feeling about the answer, and planned to add one more reference, claiming this satellite was meant to validate the launcher only here, but only found it in French. It has telemetry recorders on-board, but the transmission antennas failed (which engineers likely had foreseen). In the end, I was left with only the first intended comment, and lacked both good references and evidence pieces to reach any conclusion. $\endgroup$ – Mefitico Oct 25 '19 at 2:52
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    $\begingroup$ @uhoh: My guess is: The stripes are made for facilitating identification and assessment of the spacecraft attitude via optical telescopes. Radars work only for orbit, but they might confuse satellites with similar orbits and radar cross-section. Also, because it is an early experiment, both the injection orbit could be off-target and the antennas could have broken, making the telescope assessment a backup method. The lines are around the spin axis and large enough to differentiate at the perigee, but I'm missing a lot of research to uphold those claims. $\endgroup$ – Mefitico Oct 25 '19 at 4:10

To address only Astérix: Space Archaeology has a different picture and a writeup:

enter image description here

Weighing 42 kilograms, the satellite was a distinctive striped fibreglass spinning-top shape half a meter in diameter, the black stripes to provide passive thermal control.

I suspect the picture is of a replica, and this is not a primary source, but maybe it'll do until something better comes along.

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    $\begingroup$ "Thermal regulation" is always the throwdown answer! I too would like to see more detail. $\endgroup$ – Organic Marble Sep 4 '19 at 22:21
  • $\begingroup$ Nice find, thank you for posting! Now that we can see that the surface (at least of this likely replica) looks more like brushed metal than white paint, the surface looks much more like the other early satellites, but I don't see any of those reflections in the poor reproduction in the question, so we can't be sure yet I guess. The dark areas will absorb heat from the Sun more rapidly, but radiate it back into space more rapidly as well, so I'm not sure what the net effect will be on the spacecraft's temperature as it passes in and out of the Earth's shadow. Cool problem (pun intended). $\endgroup$ – uhoh Sep 4 '19 at 23:55
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    $\begingroup$ I've just added a bounty in case "something better" has come along :-) $\endgroup$ – uhoh Mar 4 '20 at 4:39

Several of the early satellites, including the first US satellite, Explorer, used black and white stripes to control the satellite's temperature by adjusting the a/e (absorptivity-to-emissivity) ratio. (Ref 1 and image below) The white strips have low absorptivity and low emissivity while the black stripes have high absorptivity and high emissivity. The first US satellite to use a thin film temperature control coating (rather than black and white stripes) was the Vanguard satellite launched in 1958 (Ref 2). The Vanguard coating was developed by Thomas Cox and Alan Bradford under the direction of Georg Hass (Ref 3) working at the Ft. Belvoir Engineering Research and Development Laboratory that later became the Army Night Vision Laboratory. Georg Hass also helped jump start optical thin film work at the newly formed NASA by mentoring James Heaney (Ref 4) at Goddard Space Flight Center. Heaney became a leader in NASA's optical thin film application to many programs, including the James Webb Space Telescope and the temperature control coating for the Wilkinson Microwave Anisotropy Probe (Ref 5)

Figure 1: The Explorer Satellite

Much has changed in the last half century or so. Spacecraft outer surface coatings, with few exceptions, must now be electrically conductive to minimize the possibility of ESD (electro-static discharge). Many spacecraft don't have a thermal control coating, utilizing MLI (multi-layer insulation) instead. You can see this MLI in the figure below showing the New Horizons spacecraft. The gold color can be due to gold coated Mylar or aluminum coated Kapton (Ref. 6). On the left is the RTG (radioisotope thermal generator) whose outer surface is black for maximum emission of heat into space. On the upper right is the cold patch of the passive cooler for Ralph**. The patch appears white in the visible so as not to overheat the sensitive detectors when in the inner solar system, but is very black (high emissivity) in the infrared, so cools the detectors to less than 135 K when in the outer solar system (Ref 7). These are examples of three different kinds of thermal control surfaces: one black (emissive) at all wavelengths, one highly reflective at longer visible wavelengths and the infrared, and one highly reflective in the visible and highly emissive in the infrared.

** Ralph as in Ralph Kramden from the old Honeymooners show! (It's next to a UV spectrometer called Alice).

MLI on New Horizons

Ref 1 Spacecraft temperature control https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20010014168.pdf

Ref 2 First application of an optical thin film coating for satellite temperature control https://materion.com/-/media/files/advanced-materials-group/ac/ac-newsletter-article-pdfs/coatings-used-in-space_technical-paper.pdf

Ref 3 Georg Hass https://www.osa.org/en-us/history/biographies/bios/georg_hass/

Ref 4 James Heaney https://www.spiedigitallibrary.org/profile/James.Heaney-5357

Ref 5 Thermal control coating for the Wilkinson Microwave Anisotropy Probe James B. Heaney, Charles C. He, Wanda C. Peters, Robert R. Gorman, Samuel Dummer, Cliffton E. Jackson, J. T. VanSant, "Thermal radiative properties of the microwave anisotropy probe telescope," Proc. SPIE 4444, Optomechanical Design and Engineering 2001, (5 November 2001); https://doi.org/10.1117/12.447293

Ref. 6 Gold coatings and MLI https://curiosity.com/topics/nasa-uses-gold-on-its-spacecraft-curiosity/

Ref. 7 Ralph on New Horizons https://www.boulder.swri.edu/~tcase/SPIE_Ralph_final%20Reuter


"The answer is always thermal control"

San Marco-1


NASA Space Science Data Coordinated Archive / San Marco 1


This was the first French satellite, launched in 1965. It's painted with stripes as a form of temperature control - the black absorbs heat, the white reflects.

Australian Broadcasting Company

  • $\begingroup$ "For thermal control" isn't completely satisfying me, I gotta wonder why they didn't just grab a can of gray paint instead of "the pronounced alternating white and black stripes". I still think that "Europe's first few satellites were so stylish" for a reason. However there may be more details in the links. Thanks! $\endgroup$ – uhoh Mar 4 '20 at 16:11
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    $\begingroup$ I'd like more too. There's an informative book about the San Marco project on NTRS here: ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740004978.pdf but sadly it doesn't even mention the passive thermal control system. Asterix was very hard to find details on. $\endgroup$ – Organic Marble Mar 4 '20 at 16:27
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    $\begingroup$ Okay I've asked a new question: Are black and white stripes any better than uniform gray for thermal control? $\endgroup$ – uhoh Mar 4 '20 at 23:59

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