LAUNCH DATE: June 6, 1998
LAUNCH TIME: 14:00 UTC - 08:00 MST
LAUNCH SITE: Laramie, Wyoming


  • 41 deg 18.81' North
  • 105 deg 39.62' West


  • 41 deg 17.8146' North
  • 104 deg 43.011' West

ACTUAL TRACK: 91 Degrees, Approx 48.9 Miles

PREDICTED TRACK: 96 Degrees, 51.1 Miles

Error of 4.4 Miles on a bearing of 349 degrees from predicted landing point.

FLIGHT EXPERIMENT: High Altitude (EOSS) Record Attempt


  • Launch Site:
    • Simplex 146.550 MHz
  • GPS - APRS (independent package - AA0P-11)
    • 144.390 MHz with EOSS digi on board
  • Crossband Repeater
    • input 445.975 MHz - dead at liftoff
    • output 147.555 MHz - Beacon worked throughout flight
  • Telemetry:
    • No Standard Packet - weight considerations
  • ATV:
    • No ATV - weight considerations
  • Foxhunters:
    • 145.115 MHz NCARC
    • 145.325 MHz - Wyo repeater
    • 146.58 MHz Simplex Field Frequency


  • DeLorme Tripmate GPS firmware quit reporting course, speed and altitude above 30,000 meters. Lat/Long info still available to tracking teams.

Flight Recap

by Larry Cerney, N0STZ

Most of the EOSS crew traveled to Laramie Wyoming Friday for our first ever out of state flight. We were invited by Norm Kjome who flies balloon for a living. Norm has help us out on a number of flights in the past and when he heard we were going to try for an altitude record, he volunteered a balloon and gas. The catch, we had to fly it from Laramie.

The weather wasn't very good when we left Denver. A stationary front had parked itself right up against the front range of the Rockies and had us socked in for a couple of days with cold weather, snow (in June) and rain. The trip to Laramie was very wet.

Saturday morning was beautiful. The plan was for us to try for a verified altitude record using the DeLorme Tripmate GPS which we have flown before with great success. Jack, AA0P, had trimmed down his APRS package to about 2.25 pounds. Norm was offering us a 3000 gram balloon and gas and the Rocky Mountain Radio League had lent us their crossband repeater which weighed 2.75 pounds. With these packages weighing 6 pounds and a large balloon, we fully expected to reach 125,000 feet.

As I said the morning was beautiful. Not a cloud in the sky, temperature in the mid 50's with just a slight breath of a breeze. It couldn't have been better. Preflight operations moved smoothly, everything tested out O.K. and we were ready for the 0800 launch.

The balloon was released and lifted straight up into the clear Wyoming sky. Now, you know Murphy would have to be lurking around somewhere, right? Immediately after the release I tried to make the lift off announcement and realized my transmissions weren't going through the crossband repeater. I tried another radio, no joy. Others tried and had the same result. It seem the 70 cm input side had gone deaf. The 2 Meter side transmitted a good signal throughout the flight and I hope to hear from those of you who did hear our balloon. We're sorry the crossband didn't work and we hope to get it fixed and try it again soon. But wait, Murphy wasn't done yet.

The balloon rose at a rate of about 1000 feet a minute and after getting good GPS data for over an hour and a half, we lost all but Lat/Long at 30 kilometers altitude. That's 98,425.44 feet for you metricly handicapped. The balloon continued to rise for some time and we estimated burst from radical change in telemetry and direction. We think we rose to around 125,000 feet, but more detailed examination of the data needs to be done. And, was Murphy happy now? No! We were also flying, for the first time, a balloon cutdown device hoping to cut away the balloon remains. While the cutdown device worked, the gyrations of the balloon during the flight had twisted the cord tightly on a rigging ring. The cord was severed but it would not slide through the ring and allow the separation of the balloon from the payload.

While EOSS-35 was flying, Norm, thinking it was such a nice day, launched his own balloon about an hour after ours (his really). We continued tracking balloon one (EOSS-35) until touchdown. Once Jack, AA0P, had an eye on EOSS-35's parachute on the ground, we then switched recovery operations to Norms balloon. Jack remained at the touchdown site of EOSS-35 and recovered the balloon and payload while the rest of us concentrated tracking efforts on balloon two.

Balloon one (EOSS-35) traveled about 50 miles from Laramie to about 25 miles Northeast of Cheyenne Wyoming. Balloon two traveled pretty much along the same track and landed about 30 miles North on Cheyenne.

Both balloon payloads were recovered and returned. In a recent E-Mail from Norm, he said that he believed his balloon reached 125,000 feet by conservative estimate but could possibly have reached as high as 131,000 feet. Norms package also used the DeLorme Tripmate and had the same altitude reporting problem beginning at 30 Km altitude.

It's too bad that the Tripmate's won't read altitude higher than 30 Km. I guess that wasn't in their design plan. We still don't know high we really flew, but we know we can get near 120,000 feet with the right combination of light weight payloads and good size balloons.

The weekend was great. Two up, two down and two back home. I can't wait to do it again....

Thanks Norm, from your friends at EOSS........