The 'Fireflies'

I believe it was a release of the waste storage contents from the capsule.

In other words, it was drops of urine floating in weightlessness around the capusule. (If you remember Apollo 13, I believe they refer to it as the "Constellation Urion" or something to that effect).

Kinda kills the coolness of it, so I'm glad they left it something of a mystery. I like the notion of the Aborigines' campfire floating up to outer space much better.

The excellent documentary "Moon Shot" from 1994 featured a scene with the surviving Mercury 7 astronauts sitting at a table (at the time, I believe there were five of them still living) discussing this issue.

Alan Shepard refers to it as "Constellation Urine" (pronouncing "urine" with a long "i"), and they all share a hearty chuckle. Not sure if he invented that phrase or if it was astronaut lingo. Indeed, it is the same term used in "Apollo 13", which was released the following year.

Carpenter was so fascinated with the "fireflies" that he strayed off the flight plan to investigate them, which - along with other similar activities - really irked NASA. He never flew into space again. But, he did discover that it was related to the ejection of urine from the capsule.

Why this was treated with such mystery in "The Right Stuff" is beyond me, as these facts were already known.

It wasn't a waste or urine dump. The Mercury capsules weren't equipped for bathroom use. They used diapers, IIRC.

The origins of the "fireflies" were solved on the next flight, Aurora 7, flown by Scott Carpenter:

"At dawn of the third and final orbit, Carpenter inadvertently bumped his hand against the inside wall of the cabin and solved a mystery from the previous flight. The resulting bright shower of particles outside the spacecraft - what John Glenn had called "fireflies" - turned out to be ice particles shaken loose from the spacecraft's exterior."

Ignore list: cjh8504

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