September 20 – Launch of Surveyor 2 (1966)

Today we mark the launch of Surveyor 2 from Cape Kennedy in 1966, headed for Sinus Medii, but which crashed at or near the crater Copernicus three days after launch, following a spin caused by a faulty thruster.

Model of Surveyor 2. (Photo credit: NASA.)

The purpose of Surveyor 2 was fairly simple. It was a flying camera, designed to image the lunar surface, and possibly perform a “lunar bounce” (basically, fire up the engines to jump up and down on the Moon to test the surface consistency). This was needed as part of the preparations for manned NASA missions to the Moon.


1979 – Launch of HEAO-3

1969 – Discovery of comet 67P Churyumov-Gerasimenko.

September 20 – Launch of HEAO-3 (1979)

Two and a half tonnes of HEAO-3, the last of its kind, were sent 486 kilometres in a generally upwards direction on top of an Atlas-Centaur launch vehicle on this day in 1979, on a planned 6 month mission, which eventually stretched to 21 months, to study x-rays, gamma rays and cosmic rays. HEAO stands for High Energy Astronomy Observatory.

Launch of HEAO-3 (image credit: NASA)
Launch of HEAO-3 (image credit: NASA)

HEAO-3 carried three experiments, described very briefly below:

1) The High Resolution Gamma Ray Spectrometer could have had an even longer name, as it was designed to study x-rays as well. Its purpose was to perform an all-sky survey, looking for x- and gamma-rays within a certain energy range.

2) The Cosmic Ray Isotope Experiment, whose primary purpose was to measure the isotopic composition of cosmic ray nuclei, as part of the drive to better understand the nature and propagation of cosmic rays.

3) The Heavy Nuclei Experiment did exactly what it said on the tin. It searched for heavy (and so-called super heavy) nuclei in cosmic rays.

So, here we are, 40 years later, and we still don’t quite understand how, why and where cosmic rays originate. But at least we’ve sorted one problem out: we know they’re not rays.

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ALSO TODAY . . . .

1966 – Launch of Surveyor 2.

1969  –  Discovery of comet 67P Churyumov-Gerasimenko.