Light Painting the Sky
As I watch the mortars setting up on the beach, I thought I should share my all-time favorite rocket launch photo (culled from a pool of over 50,000 where luck and reflex often dominate).
This particular one was an unusual mix of preparation and serendipity. I envisioned this “Shoot the Moon” perspective during the prior day and suggested it to our embedded WIRED photographer. So at dusk, we set our tripods to bisect the Black Rock Desert moonrise for the night launch later in the evening. Most importantly, I aligned the horizon line, locked in the manual focus and peculiar angle for my 16mm wide-angle lens (capturing the action from ground to about a half-mile up). And f/2.8, 14 second bulb mode exposure to get the stars, and a distant fire made the moon blood red. The cloudscape was a surprise bonus.
The serendipity came when my rocket motor failed in a most spectacular manner. My BSD Diab-Glo “survived” a lawn dart into the playa the prior year, and now with a new nose cone, avionics bay, and extra spotlights to light up the parachute, it has a total of 24 multicolor LEDs blinking in manic patterns.
This time, the Aerotech Green Mojave propellant burned brightly, lighting up the playa and the neighboring launch rails, but it also burned through the center of the forward closure (melting aluminum) and torched the electronics of the bottom section… and even burnt right through the “fire-proof” kevlar cord that was holding the top and bottom half of the rocket together.
So the two sections separate mid-way and both are unstable. The motor without nose goes into a corkscrew and then fades to darkness. The nose cone, luckily, is still connected to the HCX flight computer, which continues to operate like a charm and detects apogee (from the accelerometers and baro sensor) and pops the parachute as programmed (there is a fire-block between the bottom and top half of the rocket, so the upper half is in perfect shape and will be reused).
Near apogee, there is some white smearing as the parachute deploys with the LED spotlights illuminating it. Then the nosecone and avionics bay drift back to the playa (to the left) at a fairly constant speed, so the blinking light pattern makes a spiral candy cane in the sky.
And if that wasn’t surreal enough, moments earlier, we saw the ISS streaking overhead like an orbiting bright asteroid.
So for New Year’s, here’s a small collection of night launches, some with the rocket’s red glare (with props to strontium chloride for that): http://www.flickr.com/search/?q=night+rocket&m=tags&w=44124348109%40N01&ss=0&ct=0&mt=all&adv=1&s=int
My short primer on solid propellants: http://scienceblogs.com/photosynthesis/2009/05/22/rocket-propellant-types/
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