Flight Recap of EOSS-16

Launch date: May 1, 1994
Launch time: 15:05 UTC
Launch site: Thunder Ridge Middle School
                   Aurora, Colorado  USA
Launch coordinates:  39 deg 37.383 minutes NORTH
                              104 deg 44.127 minutes WEST
Touchdown time: 18:03 UTC +- 5 minutes
Touchdown site: 1.31 Miles South East of Woodrow, Colorado USA
Touchdown coordinates:  39 deg 58.223 minutes NORTH
                                     103 deg 35.012 minutes WEST
Touchdown bearing from launch: 68 degrees
Touchdown distance from launch: 65.8 Statute Miles
Burst Time: 17:20 UTC
Maximum Altitude: 95,000 feet
Maximum Speed: 50.5 mph

 Payload Systems:
    ATV - 426.250 MHz
    Beacon - 147.555 MHz
    Telemetry - 144.340 MHz
    GPS sonde - 400 MHz approximately (commercial system test)
    Ozone Detector downloaded on telemetry frequency
    Pressure Sensor used to determine altitude
    Temperature sensors (internal and external)
    LORAN-C position determining receiver

  Flight Highlights
The flight of EOSS-16 was a great success from launch to pick-up by our great preparation, launch, tracking, and recovery teams. 

The ozone experiment conducted by the students from Ranum High School performed perfectly throughout the flight. The students gathered some great data. Congratulations to EOSS member Andy Kellett N0SIS, our student liaison for this flight, for getting everything operational with many hours of hard work.

We are hoping that the students will present their findings at the next EOSS membership meeting (5/10/94). These meetings are held on the second Tuesday of each month at the Castlewood Library at the intersection of Uinta and Arapahoe (just west of I-25) in Castlewood, Colorado. They start at 7 P.M. local time.

The ground station operations were coordinated by Brian Thomas, N0VSA. All systems were operating on gasoline driven AC power generators for this flight. These generators were provided by Amateur Radio Emergency Services (ARES) district 22 in Colorado.

FAA Liaison for the flight as well as technical assistance was performed by Mike Manes, W5VSI.

The balloon preparation team headed by Merle McCaslin, K0YUK, ran into no significant problems.

The weather was perfect for the launch with very calm ground winds. Early morning weather reports from the Rawinsonde (RAOB) data obtained from the National Weather Service via WeatherBank Info Service were incomplete only listing winds to 45,000 feet. Using Paratrak (Bill Brown WB8ELK's balloon flight prediction software) with these incomplete readings we predicted a touchdown at 69.2 miles from launch site on a bearing of 68.8 degrees. If you check the actual data above you'll be amazed at the accuracy of this prediction. However, because of the incomplete data, interpolation was used to estimate (incorrectly) the high altitude winds and we officially used a figure of 48.7 miles at an azimuth of 63.9 degrees to position our tracking and recovery teams. High altitude winds were stronger than anticipated.

The W6ORE flight controller aboard the payload performed to near perfection throughout the flight compiling and transmitting both standard EOSS packet telemetry and an Automatic Position Reporting System (APRS) location packet. Loran-C lost lock on ascent at about 30,000 feet but we were able to regain lock at about 35,000 feet and maintained lock throughout the rest of the flight.

ATV got some great shots. We may have even captured the balloon bursting on video tape. All at the ground station were very impressed!

The APRS packet tracking program worked perfectly during the entire flight. An APRS station was running at the ground control station and provided a graphic map display of the location of the balloon during its flight over eastern Colorado. Larry Cerney and Rick von Glahn ran APRS as well as GPS in their vehicles during the recovery operations. It was of great assistance in the hunt. We should soon have an HST file (used by APRS) ready for the flight of EOSS-16.

Trackers at touchdown site

The payload was recovered about 3 hours after launch. George Reidmuller and Paul Ternlund ran a tight ship. Under their skilled leadership were RDF stations:

  • ALPHA - Paul Ternlund WB3JZV (computerized triangulation station)
  • BRAVO - George Reidmuller N0NJM (net control), Marty Griffin WA0GEH
  • CHARLIE - Dan Meyer N0PUF
  • DELTA - Dave Galpin KB0LP
  • ECHO - Bob Ragain WB4ETT, Dawn Ragain N0QCW, Colleen Ragain N0QGH
  • FOXTROT - Greg Burnett K0ELM
  • GOLF - Ian Zahn KB0HKY
  • HOTEL - Rick von Glahn N0KKZ and Bob Sacco
  • INDIA - Larry Cerney N0STZ

Jack Crabtree AA0P was also in the field relaying packet data and chasing the payload with GPS.

This was probably the best radio direction finding (RDF) experience in EOSS history. Using LORAN-C as a benchmark, bearings from the RDF stations were shown to be the most accurate ever for the group as a whole.

While the LORAN-C was helpful as usual, it was the RDF data that provided the best information to lead the recovery teams to the payload. Paul Ternlund and Bob Ragain were first to the site. Paul had a slight advantage as he arrived on the road closest to the payload and was rewarded with the pleasant job of announcing the discovery of the package. The various payload, parachute and support lines were left in place for the inspection of the other members of the recovery team at their arrival.

The payload survived the flight and landing and was ready to fly again with only some minor repairs to the Loran-C antenna.

We would be interested in hearing from anyone who copied any of our transmissions. Send your QSLs to:

brian.thomas@filebank.com - (dead address, try webmaster@eoss.org)

Edge of Space Sciences
(address removed)

Thanks to all who helped out with the flight from ground station set-up to the tracking and recovery effort. We are all looking forward to the next flight tentatively scheduled sometime in early June. It should be another great time for all.