EOSS-289 Summit Middle School STEM Flight - Recap

EOSS-289 with seven Summit Middle School student payloads weighting 6.3 pounds, an experimental ADS-B aircraft beacon, two GPS-equipped radio beacons, and a 12 ft. Rocketman parachute were launched on a 1500 gram balloon from the Eaton, CO Middle School launch site (N40° 13.48', W104° 4.63') at an elevation of 4,564 feet at 8:09 AM MDT on Apr. 14, 2019.  The launch site was located just off the south parking lot.    The last packet received before balloon burst was at 9:34 AM at an altitude of 96,246 ft. after an ascent averaging 1092 ft./min.  The the maximum balloon speed of 60 mph was recorded at 9:53:15 AM at an altitude of 33,658 ft. on descent.    The parachute and flight string touched down at 10:17 AM at N40° 27.75', W103° 42.76' and were recovered at an elevation of 4,610 ft. after a flight lasting 2 hr. and 7 min. and covering 53 miles.  The horizontal touchdown speed was 9 mph and the vertical speed was 715 ft./min.  The touchdown point was about 15 miles NNW of the town of Brush, CO (N40° 15.33', W103° 37.39).  The payload string and parachute were retrived about 160 ft. off a county road in a field of stubble wheat.     NØLP

EOSS member mileage link is here.


Original Announcement: 


Note the change below for the repeater to be used for the pre-flight net on Friday.

Payload Plan Rev. C has been posted to the flight below. This version makes small revisions to the payload mass. Unless somthing dramatic changes there will be no update until the flight-morning weigh-in.

The predicitions have been stabilizing to show a landing east of Sterling, Colorado. Conditions look good for a Saturday launch from Eaton Middle School.

One 1500g balloon to fly Summit Middle School student payloads


We plan to launch from Eaton Middle School at 8:30am on Saturday May 4th. This is contingent on the weather and winds. The predicted flight path and weather conditions are shown here (make sure and select the correct date). There is always the possibiltiy that we may have to move the launch site (or launch day) if the weather is unfavorable. Keep watching this website for updates.

This is a great link, http://wxqa.com/eoss289.html  with predictions, observations, and tracking information for the flight.

Event Date: 
Saturday, May 4, 2019 (All day)
Flight Coordinator: 
Launch Site: 
Rt 71 & 14 (West), X=50, Y=40; Test N41.000, W104.000, Ans: 33.2, 66.8


A 1500g balloon for Summit Middle School student engineers and scientists

Balloon Type: 
Totex 1500g latex
12' Rocketman with wireless release
144.340 MHzAEØSS-13APRS/Digi EOSSPrimary, Timeslotted on 0:07 & 0:37
144.905 MHzKCØD-2Remote Release/DFSecondary

EOSS Preflight Net @ 8 PM MDT preceding night:

  • 449.450 MHz (-5 MHz Offset, 103.5 Hz Tone) RMRL repeater (can be accessed with DMR talkgroup 310847 or AllStar Link node 46079).  RMHAM Repeater that we usually use is down

Launch Site:
        • 446.050 MHz Simplex  
        (Note that some radios assume these are repeater frequencies and attempt to put a 5 MHz offset in the transmit frequency automatically)

Track & Recovery Operations:
        • 449.450 MHz (-5 MHz Offset, 103.5 Hz Tone) RMRL repeater (North launch).
        • 448.450 MHz (-5 MHz Offset, 100.0 Hz Tone) PPFMA repeater (Assuming we are flying out of Deer Trail).

        Simplex Frequencies:
        • 446.100 MHz Balloon #1 Field Simplex 
        • 446.150 MHz Balloon #2 Field Simplex
        • 446.200 MHz Balloon #3 Field Simplex
        • 446.275 MHz Car to Car drive out Simplex
        (Note that some radios assume these are repeater frequencies and attempt to put a 5 MHz offset in the transmit frequency automatically)

        Legacy 2M Simplex Frequency (not generally used due to desense/interference issues with the 2M APRS packets)
        • 146.550 MHz Simplex


    • DMR “North” for communications between Alpha and Ground.

2M Direction Finding Frequencies:

  • 144.340
  • 144.360
  • 144.905
  • 145.535
  • 145.645
  • 145.710
  • 145.765


Tactical Calls: 
TacticalCall SignNameNotes
AlphaWA0GEH, KC0D, N0LPMarty, Mark,NickAlpha Team
BravoW9CN, N0JPSMike, JohnAlpha Backup
CharlieKC0RPSJimFC, Tracker
DeltaK0SCCStephenLaunch, Tracker
HotelKB0UBZ, KA0ZFIBen, AnnTracker
IndiaWG0EColinTracker, Saturday Only
JulietK0JWB, K0NKKJohn, NancyTracker, Sunday Only
Ground StationN2XGL, KB0TVJJeff, Russ, RandyGround Station Gurus
TangoKC0LJohnTracker from Texas
TR Breakfast: 
Breakfast will at Drovers Culinary Cafe, 28601 US-34, Brush, CO 80723. The launch is at 8:30 so 7:30 is a good time, leave by 8:15.