As Jethro Tull sang, “Ring, solstice bells!” Happy midwinter, everyone.
Forty-five years ago today — December 21, 1964 — Explorer-26 launched on a Delta rocket out of Cape Canaveral, to study the Van Allen radiation belt. Also known as EPE-D, or the Energetic Particle Explorer, it measured trapped particles in the geomagnetic field.
Twenty years later, in 1984, the Soviet Union launched the second of its probes to Venus and Halley’s Comet. Vega-2, or Venera-Halley-2, launched atop a Proton-K rocket from the Baikonur Cosmodrome. They’d launched Vega-1 back on the 15th, as I noted in this blog entry.
And ten years ago, in 1999, ACRIMSAT — the Active Cavity Radiometer Irradiance Monitor satellite — launched from Vandenberg AFB on a Taurus rocket.* ACRIMSAT was launched as a secondary payload with the Korean KOMPSAT, and was designed to study variations in solar radiation.
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*Note that this launch took place late at night on December 20th on the West Coast; it was already December 21st on the East Coast, so different references list the launch date as one or the other. I think it made a nice trifecta to list it with these others.
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