Flight Recap of EOSS-12

Launch date: May 2, 1993
Launch time: 13:46 UTC (flight a), 17:48 UTC (flight b)
Launch site:  Colorado University
                   Boulder, Colorado  USA
Launch coordinates:  40.00834 deg NORTH
                              105.24300 deg WEST
Burst Time: 18:57 UTC
Max Altitude: 98,000 ft.
Touchdown time: 13:59 UTC (flight a), 19:50 UTC (flight b)
Touchdown Distance: 35.52 miles
Touchdown coordinates:  39.82367 deg NORTH
                                     104.61700 deg WEST
Payload Systems:

  • Colorado University GPS system
  • W6ORE Flight Controller
  • ATV - 426.250 MHz
  • Beacon - 147.555 MHz
  • Pressure Sensor used to determine altitude
  • Temperature sensors (internal and external)
  • AIR GPS Tiget

Experiments: Differential GPS by CU Students
Project Lead: Jack Crabtree, AA0P
Balloon Lead: Merle McCaslin, K0YUK
Tech Committee: Mike Manes
Ground Station: Rick von Glahn, N0KKZ
Tracking and Recovery: Greg Burnett, K0ELM

  Flight Highlights
The first launch attempt (12 A) went to about 14,000 ft. Then the cut down system received an inadvertent command (which is unverified). The parachute was released and the packages and parachute landed in some tall trees a half mile away from the launch site. The Boulder Fire Department rescued the four packages and the parachute for us. This flight had four different packages, Shuttle, Beacon, CU GPS and the AIR GPS. The balloon train was over 80 ft. long.

For the second flight (12 B) it was decided to leave off the command type cut down system and allow the balloon to burst to terminate the flight.

WX conditions were ok. There was a slight breeze. This flight was delayed from the preceding Friday because of very strong surface winds on that day, making a launch almost impossible due to the length of the payload train.

All four packages worked fine and downlinked data to the ground stations. LORAN C remained locked up throughout the entire flight. GPS and the beacon worked throughout the flight too. The landing site for 12 B was just a half mile east of the new Denver International Airport. On descent we knew exactly where we were as the runway complexes were easily identified on ATV.


Nice spread showing the first flight, descent into the trees in Boulder, recovery from same trees and the second launch and flight.