Weather Ballooning in the Rocky Mountains

It's been a while since I've done a weather balloon launch, and I've been keeping an eye on the Global Space Balloon Challenge web site. The idea is that there is a sort-of coordinated launch between April 10 and April 27 all over the world. Just for fun.

Weather in Boulder and the Front Range of Colorado in general was pretty awful throughout the first half of the launch window. There was mixed snow and rain, with snow at elevations over 5,200 feet or so and pretty horrible visibility throughout. Per FAR-101, which covers unmanned balloons, one needs at least five mile horizontal visibility to launch safely, so that ruled out a launch regardless. I kept my eye on the weather and mentioned my sort-of plan for a launch to Mike who was instantly on-board. He was around for the last CO-based launch, and knows his stuff. I mean, he's a legit rocket scientist with at least one (known) orbiting body with his fingerprints on it.

When the forecast finally called for clear weather, I gave my boss a heads up that I might take a day off with no notice. I started running some predictions.

My goal for a while now has been to get some good photos of the Rocky Mountains from altitude. It's one thing to fly over the Rocky Mountains in a jet at 30,000 feet, but what about from a weather balloon at twice the altitude? I looked for a suitable launch location with a possible flight plan over the mountains.

My first inclination was to launch from RMNP or Estes Park - it's on the East side of the divide, close to home and easy to get to. When the national park didn't return my calls (go figure...) I looked launching from within the city limits. Predictions mostly had the payload landing in the plains close to the mountains, but with a flight path through potentially two or more airspaces, including Denver International's tightly restricted class B airspace. No-go.

I expanded my search west of the divide - what about a launch over the mountain range? I ran a prediction for a release from Grand Lake, and it put the landing just past the front range near Longmont and just a short distance from my house in North Boulder. That could work, if we could somehow avoid the Longmont airport and not go so far as to breach DEN airspace. Of course too much error in the opposite direction could put it miles from nowhere, and potentially even on a snow-capped mountain of ten thousand feet or more in elevation. This would be tricky.

I set a tentative launch date for Wednesday, April 22nd, Earth Day. The weekend before was gloomy and rainy. (Though that didn't stop me from brewing beer when the rain cleared for a few hours...) I told Mike the plan and started preparing the flight computer and payload.

I have a home-made flight computer with dual independent radio systems for tracking on it that I've used the past few flights, so I dusted it off and double-checked that the code still worked. Everything was a GO, so I started thinking of the other payload equipment. I wound up buying a Canon G9 on craigslist for a flight camera, and got out my two HD GoPros. I put CHDK on the Canon - which is still amazing as always - for an intervalometer.

After destroying my last 2-meter antenna on impact, I decided to make a new one for APRS out of some 450Ω ladder line, and it worked a treat! Inexpensive, easy to make, and very performant. My kind of antenna.

I gathered the rest of the pieces - the parachute, some nylon cord, duct tape, the usual stuff - and put it together in my living room.

You must understand, I'm a procrastinator by nature. On Tuesday night, the night before the supposed launch, I started scrambling. Mike came over for some late-night Thai food and a cram session to get all the pieces of the payload together. Little tasks that seem trivial at the outset wind up taking the longest. Programming a GoPro to shoot a certain way takes about thirty seconds in your head, but about ten minutes in practice after re-learning the awful two-button interface for the umpteenth time.

A hundred of these tasks later, we had a newly-created box made of house insulation and a flight computer with three cameras ready for launch. We decided to meet at 5am the next morning, aiming for an 8am launch from Grand Lake.

5:15 rolled around and the four of us - me, Mike, my photographer friend Lucas, and my girlfriend Sheehan - had all gathered at my apartment. By 5:45 we finally had the RV packed up and ready to head out to Grand Lake for launch.

It's about a 2.5 hour drive from Boulder, and Mike was gracious enough to take the wheel and let me hack on the payload in the back of the RV. Having a large vehicle with shelves, space and a reliable power inverter made all the difference when trying to code, check tracking systems, string payloads and maybe even sneak a nap. We drove through the sunrise and made it over Berthoud pass in record time given the 20-foot vehicle.

As we approached Grand Lake from the south we kept an eye out for a suitable launch location. I didn't do my homework, but I'm a good improvisor - and so is Mike, who spotted a sign for a closed-for-the-season golf course with a nice, large parking lot. There was a truck parked out front, so I barged in and hollered around a corner into the kitchen where I startled a bearded man who was putzing about.

"Hey, I'm going to ask a really strange question...", I started.

"I've probably heard stranger."

"Do you mind if my friends and I launch a weather balloon from your parking lot?"


In his defense, he probably has heard stranger questions, but it did catch him off guard a bit. Luckily he's a ham radio operator like myself, so he was instantly on board with the launch.

We pulled the RV around in the lot and parked with plenty of clear space to lay out the payload train. We unloaded everything - tarp for laying out the balloon, the 250 cubic foot tank of hydrogen gas, parachute, payload and all the bits to keep everything together, least of all duct tape and cable ties.

All in all, it was a fairly uneventful filling, which I much prefer. The balloon had no issues, the brand new regulator worked, the batteries were all charged, the payload started transmitting immediately - thing were going almost too well for launch.

I ran one last prediction, and decided to overfill the balloon at the last minute. This would err on the side of caution with regards to landing location, preferring a mountain landing to a city landing with a potential airspace breach. Overfilling causes the balloon to rise faster and burst earlier than underfilling, which might also risk a "floater". Nobody likes a floater. (Except K6RPT, but he owns that space)

Lucas got some great photos of the launch.

He got some great polaroid shots as well, which he graciously posted on his site.

Mike took a few with his phone as well.

Even the payload itself took some photos of the occasion!

Upon release everything went just as planned. The payload rose, a bit erratically at first, but then headed due east, rising at just over a thousand feet per minute.

One of the reasons I liked this flight path was it put the payload directly over Long's Peak, which I've summited several times during the summer months.

As soon as we said goodbye to the balloon and payload, we hurriedly packed up the H2 tank and piled back in to the RV for the three hour drive to the predicted landing site.

The flight continued over the mountains and ... well, I'll let the photos do the talking.

The balloon rose to 86,393 feet - not as high as I'd like, but I did want it to burst early. Thirty minutes or so later the payload landed, not far from highway 36 just west of Lyons, CO. It fell a bit short, but again, pretty on target given the overinflation. Luckily it wasn't too far off the beaten path. Or so we thought.

We were about an hour and a half out, watching the payload descend through the eyes of two radios and a computer screen, when the it landed. Great landing site on the map, a damn-near perfect flight. High-fives were shared and we pushed on, taking the peak to peak highway up north to Lyons.

Mike turned the vehicle off the highway and onto a dirt side road, the road closest to the payloads resting place according to all three GPS tracking systems. Down the dirt road, we got the the point on the road closest to the payload, just three hundred meters away. Mike expertly flipped us around and parked the RV, where we all jumped out and started toward the beacon.

I walked a bit down the road and flipped on the radio and its directional yagi antenna, hunting for the 10mW beacon. I found it, the payload was still transmitting and very close by!

We trudged up the hill. It must have been a 45° angle the whole way up those three hundred yards, but we persisted.

About 50 feet out, I hollered down, "I have eyes on it!"

In a tree. Far up a tree.

See it up there?

Continuing undeterred, I took off my baggy flannel shirt and started climbing. I scaled ~35 feet up an adjacent tree and swung over for the payload. I snagged it with a branch and cut the payload down, sending it tumbling to the ground. After carefully descending the tree again, I gathered the bits and pieces and headed back down the hill.

We all gathered back at the RV and piled in once more to head to the nearest brewery for a beer and to see what photos the payload had captured.

Unfortunately the GoPro that was facing straight down stopped recording just before the flight started, so there aren't any flight photos from it. In addition, the G9, which was set to focus once the first frame, wound up refocusing on my pants just before launch causing the subsequent photos to be a tad out of focus. Lessons learned.

Brennen met us at the brewery where we shared our story over beers and got a first look at the flight photos and data. Not bad for an impromptu flight!

A huge thanks to Mike Grusin and Lucas Hayas for additional photographs in this piece.