Canon EOS 5D Mark II
ƒ/2.8
35 mm
1/0
400

Mojave Green is the name of the Aerotech propellant. (click photo to enlarge)

My Nike Smoke screamed into the night on a J500 motor, weather-cocking into the wind… but the LED light control electronics could not take the g’s, and so she went dark… somewhere overhead in the eerily silent night sky. We all looked up and listened.

Someone said they heard the pop of the parachute, who knows where, and so the recovery would have to wait ‘til the morning.

P.S. The neon green comes from barium ions excited in the plasma and dropping to their ground state, releasing photons of a precise wavelength. The ions come from metal chlorides: Barium Chloride (BaCl) for green, Copper Chloride (CuCl) for blue, or Strontium Chloride (SrCl) for red. These metal chlorides generally do not exist at room temperature or are too reactive to add as an additive, so precursors are mixed in, and they react during the burn to create the desired molecules. The Chlorine comes from the Ammonium Perchlorate oxidizer for free, and one need only add metal salts such as nitrates or carbonates to provide the metal atoms. In this case, Barium Nitrate is the additive that forms BaCl during the burn to emit a laser-like green in the flame. (propellant primer)

19 responses to “Mojave Green in the Black Rock Desert”

  1. Meanwhile, the fairies frolic at night, and a certain someone found a way to open glow sticks and make things glow…
    Frisbee Glow Face
    from the frisbee to the car hood.

    First thing Sunday morning… Becky found the rocket while patrolling about on motorcycle.

    IMG_1557

    …a classic playa divot with most of the rocket slammed underground.

    and the dig to remove all of the FOD
    IMG_1562
    About two feet of fiberglass body tube slammed past the nosecone and LED electronics bay. It reminds me of the joke: "What’s the last thing to go through a fly’s mind when it hits the windshield?"

    The aftermath of impact energetics are always interesting to unravel.

    The post-mortem was conclusive and a classic failure mode. I wanted to fly this airframe multiple times Saturday night and so I did not include the avionics bay relying instead on motor ejection for parachute deployment. This is fairly reliable with single use motors and CTI motors (38-54mm) as the delay grain to BP charge interface is factory built and sealed. I was flying a hand-assembled Aerotech J500G and made the classic mistake of adding too much lube to the head end, which covered the top of the delay grain. I knew of this problem, and thought I could fix it by wiping away the excess and scraping away the top of the delay grain surface. But alas, it was insufficient. In extracting the motor, I found all of the BP unlit and still waiting to do its job – deploying the parachute.

    The good news is that this should be a quick and easy repair! While it may not look like much, the fin can and motor are about 90% of the labor and 80% of the materials cost of this rocket (the blinky nose cone is the major loss). For the body, I have a fiberglass payload section and coupler ready to go – I just need to epoxy it to this tail and will be ready to fly with other 4” nose cones. I built the tail to be pretty indestructible – with embedded jenga blocks between bulkhead and fin tabs, and expanding epoxy foam throughout. This was a good test of that. =)

  2. Curious about the extreme results at this particular event
    speed,altitude ?
    Any elaborate multistage launches…etc

    Your damage assessment shows your perennial optimism…:)

  3. Looks like fun, as usual. I be the recovery is a large part of the fun.

    Amazing photo of he launch!

  4. Beautiful night shot – amazing sky color with stars and it is huge (judging by the scale).
    very cute kids pictures, especially glow in the dark one:) actually, the other one is very sweet too… future space travelers!

  5. The chemistry is interesting as well as the image of the frisbee. It reminds me a little of a time-lapse shot I’ve seen on Flickr of a boomerang with glow sticks attached. That would probably be an ideal location for such an image.

  6. or a frisbee with glow goo attached… (with my blinky rocket pre-launch on the right)

    night frisbee

    [http://www.flickr.com/photos/34420997@N05] – overall? My highest flight was with the N1100 (photos to come) which broke 31K ft…. but Mach 1.5 might not have been the fastest (I’m not sure of some of the other folks’ M-motor flight speeds). There was a complex two stager, but one of its many computer systems failed at the pad, and we saw the premature ejection of the chute induce a startled leap by the team.

  7. Beautiful launch shot, pity about the descent. Good to hear, at least, that the Jenga blocks and epoxy foam will allow for some…recycling.

  8. Wonderful shot..& I love the frisbee!

  9. classic @jurvetson shot! Über-beautiful-awesome!

  10. Another great night launch shot Steve. Sorry about the landing, but it sounds like this will be a relatively easy fix. Interesting that no matter how much experience one has, there always seems to be another lesson.

  11. If the Ba is present why would you need the Cl? Since ionizing BaCl gives Ba+ and Cl- why do you need the middle man BaCl? Or is the Cl yanking apart the nitrates and carbonates to free up the Ba and such?

  12. Catalyst! <–That’s the word I forgot

  13. Pretty sure that BaCl is quite stable,not so different from NaCl…table salt…but its poisonous…

    Its the heat of combustion that both breaks the (? covalent) bonds between Ba and Cl
    It also ionizes the Ba producing the color.
    Ditto for Cu,Sr…etc (Fe,Mg)
    A lot of these heavy metals (as one of their soluble salts) also were/are used as insecticides etc.
    Mostly used in fireworks now.

  14. More interesting use of barium than we have in medicine!

  15. Barium – when you want a good peek in the dark. Accept no substitutes!

  16. Or if you have extra sugar
    http://www.youtube.com/watch?v=qaN8jVgmTtc&feature=related

    May still go back to work on these…Its a nice fuel…I never took enough trouble to do it properly as a kid.
    Your site gets me inspired.

  17. and this airframe is ready to fly again. I had a spare upper fiberglass airframe tube and coupler. It left an irregular gap around the airframe, so I cut a phenolic strip to match the gap and epoxied it all in place (it is not the primary load bearing element as the coupler inside rests against the upper bulkhead plate). I used some beige wood putty to fill the gaps, and sanded to a smooth finish. Here she is just before a new coat of white paint:
    IMG_5483

    A bit more damage on the back side, but the epoxy should hold it:
    IMG_5487

  18. Great image. I used it on my post Google Search October Update . The post will be published on October 17, 2012.

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