EOSS-279 Fall NDIA STEM Flight - Recap


 EOSS-279 with four student payloads weighting 6.52 pounds, two GPS-equipped radio beacons, and a 10 ft. parachute was launched on a 1500 gram balloon from the Deer Trail, CO launch site (N39° 36.63', 104° 2.53') at an elevation of 5200 feet at 07:39 AM MDT on Oct. 13, 2018.  The last packet received before balloon burst was at 9:02 AM at an altitude of 97,455 ft. after an ascent averaging 1112 ft./min.  Both the burst altitude and ascent rate were above average for a 1500g balloon.  The maximum recorded speed was 59 mph at 8:11 AM at an altitude of 41,693 ft. on ascent.   The parachute and flight string touched down at 9:31 AM at N39° 46.20', W102° 59.80' and were recovered at an elevation of 4,590 ft. after a flight lasting 1 hr. and 52 min.  The straight line distance between the launch site and touchdown point was 57 miles.  The touchdown point was about 12 miles northeast of the town of Anton, CO (N39° 44.976', W103° 13.071').  Due to a phenomenon called “Post-Burst Chaos” there was severe tangling of the payload string and parachute with chards from the burst balloon.  This resulted in a very rapid descent.  The descent profile is plotted in the chart below along with two profiles from flights with normal descents.  The last data point on the EOSS-279 curve shows the “bundle” of payloads, parachute, flight cord, and balloon chards impacting the ground at about 40 miles per hour.  For reference the 14,000 ft/min line on the chart represents 159 miles per hour (mph).






Mileage Link (for members):  https://goo.gl/forms/1P2ZxeN5YDLFLeoA2

Original Announcement: 

NOTE: NEW 24hr PREDICTION to dowload. To meet an FAA request, we have increased the planned ascent rate to 1329/910 fpm. A new 24hr prediction was posted to the website at 5:26pm. Check the prediction page and look for the 1329 fpm in the gray bar below the 24 hr predictions. The prediction is now somewhat shorter and spends less time in the DIA departure corridor.

We are "go" for a Deer Trail Launch at 0800 on Saturday 10/13/2018. Please have the payloads to the site for weigh-in and stringing by 0630. Flight and weather predictions are available for Deer Trail at the prediction link shown below.

Various tracking, prediction, and observations links are available at http://wxqa.com/eoss279.html .

One 1500g balloon for the Rocky Mountain Chapter of National Defense Industrial Association-sponsored student STEM payloads from multiple schools.

Balloon flight prediction is located at www.eoss.org/predict and will be updated on a daily basis. Click on the "GIF" link for the date and launch site of interest. We are planning to launch from Deer Trail Colorado at 8am on Saturday October 13th.

Event Date: 
Saturday, October 13, 2018 - 00:00
Flight Coordinator: 
Launch Site: 
Last Chance: x = 40, Y=30, Test: N 40.000, W103.00 Ans: X=71.3, Y=47.9

EOSS-279 Lite

This balloon will carry 160 student experiments from the following schools:

  • Texas Middle School
  • Mountainside Elementary
  • Monroe Elementary
  • Trailblazer Elementary - Gifted and Talented students
  • McAuliffe Elementary - Gifted and Talented students
Balloon Type: 
Totex 1500g Latex
10 foot nylon spherachute with fast release and thermal cutter
144.340 MHzKCØD-14APRS/Digi EOSSPrimary Beacon
144.905 MHzKEØBMV-11APRS/DF/CutterSecondary Beacon

EOSS Preflight Net @ 8 PM MDT preceding night:
        • 449.225 MHz (-5 MHz Offset, 141.3 Hz Tone )  RMHAM Repeater  
        • 146.940 MHz (-600 KHz Offset, 103.5 Hz Tone) RMRL Repeater if the RMHAM machine is down
        • 146.640 MHz (-600 KHz Offset, 100.0 Hz Tone) DRL Repeater will serve as a backup to the backup repeater 

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:
        • 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

2M Direction Finding Beacon Frequencies:

  • 144.340
  • 144.360
  • 144.905
  • 145.045
  • 145.535
  • 145.645
  • 145.710
  • 145.765


Tactical Calls: 
TacticalCall SignNameNotes
AlphaWAØGEH, KCØD. NØLPMarty, Mark, NickAlpha Team
BravoW9CN, KBØYRZ, NØJPSMike, Chris, JohnTrackers, Alpha Backup
CharlieKCØRPS, WØNFWJim, GeorgeFC, Trackers
DeltaKØSCCStephen, KallieLaunch. Trackers
EchoKEØORBJohn, NancyTracker
FoxtrotN6BA, KØLOBJeff, JimTracker
HotelKE7KCKTomPresident, Tracker
IndiaKE0NDW, KEØRDL, NB4VAnup, Colin, Braedon, Cody, OonaughTrackers, C-Base Students
JulietNØIXDoug, AmandaTrackers
TR Breakfast: 
Launch at 8:00, thanks Jim! Breakfast for the folks coming from the south will be at the IHOP in the Flying J Travel Center (north of I-70 at the first Limon exit [359]) at 5:30am, leave at 6:15 for another 90 miles of travel. This will work for the folks coming in from the south, not so good for teams coming in from the north who will venture straight out Highway 36. For those folks, we will gather for snacks at Anton. That store opens at 6:30. We will probably lose the 448.450 PPFMA repeater near Anton. Please call Alpha on 446.100 and maintain communications on that simplex frequency. It will be cold, so dress appropriately for the field recovery. Predict: 8 mi NNW of Kirk, CO (NS CR-K & EW CR-13) (X 91.1 Y 30.7) Weather forecast for Deer Trail at 0800 Saturday: Clear skies, cloud cover <10%, Visibility unlimited, Temperature 38, dew point 27, winds W @ 5 mph