UX-1 Balloon Flight Mission (May 14, 2005)
AFTER A FLIGHT OF 150 KM (90 MILES) AND ACHIEVING AN ALTITUDE OF 52,000 FEET, UX-1 HAS BEEN RECOVERED. THIS WAS UTARC'S FIRST BALLOON ATTEMPT. STAY TUNED ON THIS PAGE FOR DETAILS.
Addendum for those in the Slashdot crowd who have been wondering: our balloon was exempt from requiring a waiver, but we notified all appropriate authorities in advance anyway.
|Photo from Altitude||Mike (KJ4Z) with Payload and Dan (K2VOL)|
APRSworld.net Ground Track
AA4UT-1 Flight Path
AA4UT-1 Landing Site
Images from Payload Camera
Random Image Treasure Hunt
Balloon Prep and Launch Video (low bandwidth; 7.5MB)
Balloon Prep and Launch Video (high bandwidth; 31MB)
Launch Only Video (low bandwidth; 744kB)
Launch Only Video (medium bandwidth; 3.4MB)
Launch Only Video (high bandwidth; 12MB)
Balloon Recovery Video (low bandwidth; 6.4MB)
Balloon Recovery Video (high bandwidth; 22MB)
Balloon Prep Clip 1 (short; 2MB)
Balloon Prep Clip 2 (short; 3MB)
Balloon Recovery Clip 1 (short; 8MB)
Balloon Recovery Clip 2 (short; 5MB)
Balloon Recovery Clip 3 (short; 4MB)
Balloon Recovery Clip 4 (short; 17MB)
Balloon Recovery Clip 5 (short; 9MB)
The UX-1 Storyby Mike Coffey (KJ4Z) and Dan Bowen (K2VOL)
Dan (K2VOL) and I originally decided we wanted to launch a balloon in the Spring of 2003. We had seen a few articles about hams launching balloons, visited a few websites about their adventures, and thought it sounded like something we'd like to get into. We made plans, did some research, and then life intervened. A year went by without any further real action. In the Fall of 2003, I acquired several Dakota Digital cameras with the idea that they might be useful for the balloon. In the Summer of 2004, we decided it was time to get our acts in gear. I assembled a Hi-Value Radio PocketTracker, and Dan bought two latex balloons from Kaymont and a parachute from Public Missiles. We also found a closeout on DigiTraveler GPSes at RadioShack, and bought all that they had (for $20 apiece). Then, once again, we got busy, and another year went by. It wasn't until March 2005 that the topic came up again in a UTARC meeting. We decided that it was imperative to set a date for the launch, or it would never happen. Half randomly, we chose May 14, 2005, with a rain date the following day. Little did we realize what we were getting ourselves into...
One day, a few weeks before the scheduled launch, it dawned on us that there was still much to do -- too much, it seemed. Although we had all major flight systems more-or-less together, overall assembly had not even begun, and we really had only the vaguest notions of what we needed to do to get everything ready. Dan put out requests for assistance on the UTARC email list, and we both began doing research about the next steps. Dan decided the best way to proceed would be to have separate launch and recovery crews. The task of the launch crew would be to get the balloon safely into the air; after that, the recovery team would take over and chase it, with the eventual goal of recovering the payload. Fortunately, several people piped up and volunteered to be part of the recovery team, and Jeff Napier (AF3X) volunteered to find a launch site for us. That meant it was up to Dan and me to get the balloon itself ready. We found a small styrofoam cooler that we thought would be a good container for the payload, as it was lightweight and would keep everything insulated. Dan built a circuit board to contain the various control systems for the balloon, and I built a half-wave dipole antenna for our tracking system. We requisitioned a canister of helium from Holston Gases, which turned out to be a bit of a bureaucratic ordeal, and then went to pick it up a few days before launch with the assistance of Don Riley (N4CZL). Physically, we now had all the parts of the balloon, but the fun was just beginning.
As anyone who works with modern electronics knows, hardware is only half the equation, and so it was with the balloon. Dan spent a great deal of time in the runup to launch programming the software for the Basic Stamp microcontroller that would govern the balloon's overall operation. Basically, this device is a small computer that controls the GPS, radio, siren and strobe. If the microcontroller does not function properly, there is an excellent chance that the balloon and payload will be lost. At the same time, I was working to apply software patches and hacks to the digital camera so that it could take more photos on our flight. By this time, it was the Friday night before the scheduled launch, and I went home, thinking Dan would also be wrapping up in a few hours. What I didn't realize was that he would actually never go to bed that night.
Dan spent the entire night working on final assembly of the payload and programming the microcontroller. At 4:30 AM, he discovered that the expensive, lightweight lithium batteries we had bought from surplus were completely dead. Without the lithium batteries, we could either postpone for a week, or fly with regular heavy alkaline batteries, which would put us outside of our known weight calculations. With only 20 minutes remaining before departing to pick up the launch crew, he spotted five 9-volt battery connectors in the shack -- our only hope. Soldering frantically, he tore the payload apart and attached the new 9-volt connectors in. All of our careful calculations were now useless -- we had no idea how long these different batteries would power the balloon, nor how much weight they would add.
Morning dawned early on Saturday; there was a frantic 5:30 AM Wal-Mart run for those last few forgotten components, and then we were on the Interstate, headed down to Watts Bar. Jeff had suggested this area, about 50 miles southwest of Knoxville, for our launch site. It was strategically significant because the prevailing winds from this area were unlikely to carry the balloon into the very remote mountainous terrain that lines both sides of the Tennessee valley. There are also vast open fields owned by the Tennessee Valley Authority that we hoped to use for launch. Jeff, Dan, and I went down to Watts Bar to do a site survey the Monday before launch. While there, we wandered too close to the nuclear power plant and were briefly detained by TVA security, who seemed quite interested in our doings, and were apparently quite alarmed by the thought that we would be launching a balloon and the fact that we had been found with a map in our possession. In any event, they eventually let us go and helpfully suggested the field that we ultimately did use for our launch.
When we got to the launch site, there was a powerful thunderstorm underway, and we thought we might have to scrub. During the storm, Dan and I sat in his car and made final adjustments to the payload. Dan realized that he had forgotten to bring the software he had labored all night to produce! In desperation, he wrote a quick hack that would turn off the GPS and turn on the strobe and siren after two hours (roughly) of flight time. The idea was to conserve battery power and draw attention to the payload once it was on the ground. Then, he loaded the software into the microcontroller, and we prepared to launch. Fortunately, by this time the thunderstorm had given way to a light drizzle. We all went out into the field, and began filling the balloon and attaching it to the payload. There was some confusion about how full to fill the balloon -- in the year since it had been purchased, we had lost the data on how much helium we should use in it, and we were concerned that we might be overfilling it. But, we pressed ahead till we got to the 10 ounces of extra lift that Dan had calculated we needed. Finally, at around 10 AM, everything was ready. After a quick check to assure that all systems were operational, we released the balloon and were delighted to see it drifting away into the turbulent sky. It rapidly became a small speck, and after just a few minutes, disappeared completely from sight.
Immediately, it became apparent that the ascent rate was not as high as we had been expecting. The extra battery weight and gusty winds during lift measurements at the launch site may have caused us an inadequacy of helium. Nevertheless, we hoped this would not too badly change our flight plan. Because the only method we had of getting the payload to come down was for the balloon to pop, a lower ascent rate meant the flight was going to be longer than we had expected, and travel further. As the recovery team raced off after the balloon, the launch team cleaned up the launch site and got ready to leave. Dan, Eammon (KI4FUW) and I decided to go along after the recovery team in one car, and Jeff went in another. As we drove up the Interstate, we listened to the recovery team chatting with each other over 2-meters. Every minute or two, one of them would read the latest position and altitude of the balloon, and all the people would coordinate with each other to make sure they were all headed in the right direction. The balloon's ascent rate continued to slow as it climbed higher. At this point, we came to a sickening realization: the flight was likely to last longer than two hours, which meant the GPS would turn off and there would be no more position fixes. The only way we could hope to find the payload would be through RF direction finding, or hoping that someone found the package and called the phone number printed on it. As the balloon climbed through 10,000 meters (roughly 32,000 feet), altitude stopped being correctly reported. It turns out the Digi-Traveler can only store 4 digits of altitude, so the altitude will not function above 10 km. Fortunately, latitude and longitude continued to be accurate. The balloon traveled in a long arc up the Tennessee valley, past Oak Ridge, and was over west Knoxville when its position stopped updating. It became apparent that the GPS had turned off while the balloon was still in the prime of its flight. There was some confusion about whether the onboard radio was still transmitting its last position, or if it had gone silent. We began to fear that the improvised battery bank had failed. We also thought it was possible that the balloon had landed near the last position fix, and had become inaudible after falling below the horizon. A team was dispatched to the area, but found nothing. Forty minutes had gone by since the last packet had been heard from the balloon, and the mood in our car was generally pretty glum. I concluded that all we could do now was trust to fate and hope that someone found our payload and notified us. Dan dropped Eammon off at his apartment and took me back to campus, and left to go back home. About five minutes later, I received an excited telephone call from Dan -- another packet had been received! The balloon was alive and well after all! After I got off the phone, I thought about what could have happened, and suddenly it dawned on me. For some reason, the onboard computer had crashed. When it rebooted, it power cycled all devices on board and brought the GPS back up. Miraculously, we had been granted another 2 hours of GPS time. Unfortunately for me, Dan was already well down the road on the chase by this point, so I had to observe the remainder of the chase from my computer at work.
This is Dan now, picking up where I left Mike off at UT after we had thought the balloon lost. I decided that I would try and tag along with the recovery team anyway until the last one had given up. Some of the recovery team had continued on following the track the balloon would have gone on if it was still up, and I headed northeast to find them. Just as I got on the interstate, someone cried out of my radio that they just got a position from the balloon! The position was excitedly read out, and reported to be near Mascot, TN, a small town northeast of Knoxville. The balloon had apparently continued on its course, as you can see after the long gap in the positions marked on the map. Packets of data were coming in sporadically though, not the steady stream we had been used to -- each longer gap between regular signals let fear of the inexplicable loss of the mission creep back... I caught up with William McKeehan (KI4HDU) and Tom Ogle (KE4WFJ), who had APRS position receivers and was glad to be hot on the trail.
The area the balloon was heading into was rapidly becoming rural and hilly, making it difficult to follow this windsailing balloon as it sped along in the hands of the jetstream. After just a little while of this rural navigation, someone called out that the altitude was no longer pegged at 32,000 feet -- it was falling fast. UX-1 had cheated fate. With no way to tell what altitude it was at, and seeing its climb rate slowing, we thought that it might have reached a neutral buoyancy altitude in the jetstream, and might fly until its batteries died. Now almost three hours into its flight, it was mercifully falling back to the earth, with batteries alive, and GPS transmitting. Bill Brown (WB8ELK) estimated that it burst around 52,000 feet. It was now speeding downward with only the little parachute to hold it back.
We heard the last report from the balloon as it glided down through 3700 feet, 10 miles south of Rutledge, near the Holston River. David Hoffman (KE4FGW) met up with Tom, William and me at the last heard location, to decide what to do next. We made a rough guess as to where it might have landed, and split up to canvass the twisting rolling country roads, looking for our lost ship. As we scanned fields and forests from the road, it became clear that there was a lot of land to cover, and we couldn't cover it all visually without an army or a search plane. David is a veteran of dozens of balloon recoveries and has returned victorious from every one. He was determined that this day would be no different. About that time, he received a call from a NASA engineer in Huntsville, Alabama, famed radio balloonist Bill Brown, also known as "the Father ofAmateur Radio High Altitude Ballooning." Bill took all the details we could provide about balloon's fall from the sky, and within a half hour, he had a very detailed possible location.
Now two hours after landing, with thunderstorms moving closer, and batteries very low if not dead on the transmitter, we reconvened to find the precise spot. Nearing the location, David's radio yelp nearly vibrated my radio off the car's dashboard - he had just heard from the balloon! Unbelievably, the transmitter was still going, and sent him one, and only one packet, indicating that it was almost exactly where Bill had predicted it.
We proceeded quickly to find out that neighbors thought it would be ok if we went into the field. With portable GPS, cameras, cutting tools and a first aid kit, we dove into the field. As we waded through the rippling green grass, I realized that we had quite a beautiful area to be searching, and was glad that we had the good fortune to land in a field. However, with only 500 feet to go, we could still not see any sign of the mission. Trudging on, at 200 feet we stopped when I heard a tweet that didn't sound natural. Again the melodious tweet drifted to us -- it was the beeper on the payload! Picking up speed we ran up to the final fence separating us and the now insistent warbling. Looking out over the rolling hill, we knew it couldn't be more than a fifty feet from us, but could still not see anything. I handed my cameras to David and his little girl, and carefully scaled the barbed-wire fence. With great strides I followed the homing beeper, until the grasses finally parted in front of me, the white bucket payload sitting comfortably in its grass nest, parachute draped nearby. I seized the hero of our Saturday adventure, and heaved it high for all its followers to finally see.
The payload styrofoam container and parachute survived without a single dent or scratch; even the wooden antenna dowel that protruded below was not broken. All the contents of the payload were undisturbed and functioning when we found them. The only passenger on our flight, a digital camera, proved to have had a very good flight, and took lots of pictures for us from launch up into altitudes far above 32,000 feet. As I drove home with the payload, we talked on the radio repeater to friends and and onlookers, recounting brief details to many who had to leave before the adventure had finished unfolding. It reminded me of the Mars Rovers mission control sending the news it could get to the hungry public that the rovers had in fact landed on Mars, but they didn't have pictures yet. Like the rover team, we had all the details, but couldn't get the pictures, for the payload came home with me, and I had fallen fast asleep.
This launch was a great success that would have been postponed, failed, or been lost had it not been for the amazing efforts of so many people. We have many ideas for flying again, and hope that everyone enjoyed this one and learned from it. This flight was desgnated UX-1, for UTARC Experimental - 1, an experiment in which we hoped to learn how to fly and recover balloons. I know that I've learned that and more, though for all the research that I did, the most I learned came from the people with whom I was able to work on this project. I hope to work with all of them when we fly again. In the future we hope to move our experimental status beyond flight basics to performing scientific, engineering and other experiments with a tested balloon ships and familiar crews.
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