Held on Sunday, September 22, 1996 at the Old Huntsville Airport
The following text was taken, with permission, from an article by Ronnie Lajoie and Bill Brown, which was published in the November-December 1996 issue of the Southeastern Space Supporter, newsletter of HAL5. Additional unpublished material has been added to the end by Ronnie Lajoie for this Web page. (It probably would have been published given more time and space.)
The fourth HALO Balloon Test Day was held on Sunday, September 22, when members of HAL5s Project HALO launched their largest high-altitude balloon to date. The clear plastic (polyethylene) balloon (see Figure 1) measured over 60 feet long and had a total volume of 19,000 cubic feet when fully expanded into a sphere with a diameter of 33 feet.
The crew started setting up a 8:30 AM, on a chilly and foggy, but calm, day. Launch site was the Old Airport in Huntsville, Alabama. Unlike the latex balloons launched in the past by HALO members, this would be a zero pressure balloon designed to float at an altitude of 20 miles until commanded down.
Due to high wind gusts that occurred just as we were preparing to launch, two large holes were torn in the balloon envelope. We taped the holes shut as best as we could and pumped some more helium in the envelope. Then we successfully launched the system -- Hooray! -- only to snag on a loudspeaker wire leftover from the previous weeks County Fair -- Boo! Bill was able to hook the balloons radar reflector with an 18-foot pole and pull the payload away from the line and let it go on its journey (see Figure 2) -- Hooray! Launch time was at 11:24 am. The balloon was easy to spot and appeared as a bright, shimmering spot in the sky for quite some time.
The balloon material resembled very much Paul Bunyans sandwich bag -- a 60-foot long pile of thin plastic (polyethylene). To protect it from the dangerous rigors of the old airport runway (or even grass), Ron Lajoie had purchased a plastic painters tarp 8 feet wide and 100 feet long. The team laid out the tarp on the runway along the wind vector, such that any breeze would carry the balloon along the tarp first.
Once the balloon payloads were ready (see page 4), the team was ready to begin inflating the balloon. Lack of time prevented the group from making a Kjome (pronounced cho-mie) Launcher for this event. It is named after Norm Kjome who invented an easy-to-operate mechanical device for safely launching these and larger delicate high altitude weather balloons. (HAL5 is currently preparing to build a Kjome Launcher for use on our space launch attempt, under the leadership of Greg Allison and Larry Scarborough.)
The calm of Sunday morning allowed the group to handle the balloon with hands (in soft gloves however), rather than even using a device known as a Hutch Clutch, as shown in Figure 4.
Calm you say, then how did the balloon rip? Well, on the first launch attempt, the group underestimated the flexibility of the balloon tether. As the filled balloon lifted into the air, the tether stretched just enough such that wires running along the tether to a cut-down device pulled loose, damaging a squib.
While waiting for Tim to fetch a replacement squib, the wind picked up. The HALO team valiantly fought to keep the balloon aloft as the wind increased from a zephyr to a stiff and unpredictable breeze.
Greg Allison quickly assembled a subgroup of members to use the plastic tarp as a shield to deflect the balloon upwards any time the wind forced it down. Meanwhile, Tim, Bill, and others attached the new squib and left slack in the wire to prevent another pullout.
Just as we were preparing for the next launch attempt, a downdraft slammed the balloon to the ground faster than the tarp team could react. The balloon barely grazed the surface, but it was enough. The balloon now had two huge tears in its delicate fabric. Her damage done, Mother Nature took a break and calmed the winds.
Several people exclaimed remorse and regret. Ron Lajoie ran to his car and grabbed a role of clear plastic tape. Bill Brown, Al Wright, and others taped up the holes as best as they could. The leftover helium was pumped into the last hole (faster than untying the main knot), then that hole was resealed.
The entire group of about 15 people now formed a train of balloon and payload handlers, as we guided the balloon upwards and along with the now regrowing wind. With a cheer the package was released. The balloon lifted slowly and sailed across the runway, over the grassy field.
Below the balloon proper was a parachute, followed by the electronics package (see Figure 7), followed by the nitrous tank test package (see Figure 5), followed by a radar reflector. A long string of items to be sure (see Figure 2).
Within five seconds of balloon release, an antenna attached to the tank test package snagged that speaker line. As mentioned on page 1, Bill freed the package and the balloon sailed on.
The downlinked ATV signal was fantastic with absolutely NO spinning whatsoever. It looked like an elevator ride. Great views of Huntsville and surrounding suburbs could be seen during the early part of the flight. The ascent rate was a very slow 620 ft/min. At 38,300 feet, the balloon system started to descent slowly (around 500 ft/min). We think that the tape that was covering over the holes in the balloon let loose and let the helium leak out.
The balloon ended up traveling 108 miles downrange at a heading of 122 degrees from the launchsite. It landed around 2:00 pm CDT. The balloon landed behind a house north of Villa Rica, GA (40 mi west of Atlanta).
The woman who lived in the house was washing dishes and saw the balloon descend into her field behind her backyard. She thought it was a UFO and excitedly called the TV and radio stations. She turned on her scanner and actually heard the chase team chatter as they closed in on the signals.
Foxhunters from the Atlanta area tracked APRS packet signals and low power telemetry beacons and quickly located the payload. It was lying in a bed of Kudzu behind the womans house.
All payloads survived the flight and landing in good shape. Even with the low altitude we attained, we consider the flight to be a success one, considering this is the first zero pressure balloon that we have flown. We beat the odds and actually launched the balloon in a very high wind!
On board the balloon was one of our flight-ready oxidizer tanks, filled with nitrous-oxide. This was a test to see whether or not we can keep liquid nitrous-oxide warm at about 75°F using only a 25W band heater and an insulated tube (see Figure 5).
The tube was a short piece of phenolic wrapped on the outside with R-25 insulation. Thick Styrofoam cylinders, served as endcaps. The bottom one was taped shut, but not the top, to provide access to the inside to the tank, safing equipment, and detailed instructions for safing the nitrous tank (see Figure 6).
Following the successful balloon launch, the team retired to the ground station and began monitoring the on-board color video, audio, and data telemetry. Ed Myszka and Clay Sawyer, with assistance from Bill Brown, Greg Allison and Tim Pickens, had worked many weeks to prepare all of the electronics for this balloon experiment.
Downlinked data, transmitted via HAM radio channels, included altitude, longitude, and latitude -- the three computed from on-board GPS. The data also included outside air temperature, electronics temperature, and nitrous-oxide (inside the oxidizer tank) temperature and pressure.
Air temperature dropped from a near-ground high of 88 deg-F to a low of 8 deg-F near the apogee altitude of 39,000 feet. Ed Myszka believes that the air temperature reading may have high since the probe was not placed in the shade. This will be corrected on future flights. Electronics temperature dropped from values over 100 deg-F at launch down to a low of 44 deg-F.
Meanwhile, the nitrous-oxide was staying nice and cozy warm behind its blanket of R-25 insulation (wrapped around the tube containing the otherwise unprotected oxidizer tank). At launch time, 11:29 AM, tank temperature registered at 77 deg-F. An hour later (12:23 PM), just prior to the balloon entering the stratosphere, tank temperature had only dropped one degree to 76 deg-F! The lowest reading of 74 deg-F was recorded at 12:41 PM after the balloon had reached its apogee altitude of 39,000 feet and was descending down to 36,000 feet. After this, the balloon -- now over Georgia -- descended beneath the line of sight and all contact with the ground station was lost.
Since about two hours would be required for the balloon ascent on the actual space launch mission, the drop of only three degrees over an hour was a terrific sign that an insulated tube could keep the tank warm. In fact, a 25-Watt band heater wrapped around the tank -- and set to turn on only when the temperature dropped below 70 deg-F -- never came on. Although the test was short, data indicated that the insulated tube kept the heat in and the cold out.
A large contingency of HAL5 members (and some non-members) attended and assisted this balloon launch including: Greg Allison, Bill Brown, Ed Myszka, Clay Sawyer, Tim Pickens, Al Wright, Larry Scarborough (and family), Ronnie Lajoie, James Hopkins, Brian Jones, Amy Herring, and friends. All were valuable in saving the balloon from total destruction and getting it off the ground in one piece!
A special word of thanks goes to those balloon trackers in Georgia for recovering the balloon payload and properly safing the oxidizer tank.
During setup, Ron Lajoie called local television station WHNT (Channel 19) and invited them to send out a reporter to cover the event. WHNT sent Clavius Gresham with video camera in tow. Mr. Gresham was kind enough to stay during the entire launch process (including the long wait from calm wind through stiff breeze). Both Greg Allison and Ron Lajoie were interviewed. His report aired that evening and the next morning and was well done.
The only flaw was the lead-in by the news anchor which was totally wrong, and probably not the fault of Mr. Gresham. He reported it properly as a helium balloon launched by an amateur pro-space group. The anchor led the story with NASA launches a high tech, hot air balloon! GAH! Dont believe everything you here on TV!
For more information on Project HALO, contact HALO Project Manager Yohon Lo at (256) 658-2043 or via E-Mail at: firstname.lastname@example.org.
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This file was last modified on Saturday, 15-Apr-2017 13:19:38 EDT