Recap of EOSS-121


photo by Chris Rand, KB0QQW

EOSS-121 flying formation


photo by Kjirsten(KJ) Wright



photo by Marty Griffin, WA0GEH

LAUNCH DATE: August 4th, 2007
LAUNCH TIME: 07:31 am MDT (13:31 UTC)
LAUNCH SITE: Deer Trail, CO (directions)

Pre-flight Prediction and Actual Track

Predict vs. Actual

Blue = Actual Track
Green = Predicted Ascent Phase
Red = Predicted Descent Phase

Map made with MapPoint
Prediction made with Balloon Track


Predict vs. Actual

Green Track = Ascent
Red Track = Descent
Prediction and Actual tracks made with Balloon Track

Maps by Google Earth

Launch Site - Deer Trail
Launch Point: 39.61137� lat.   -104.04255� long.
Grid: X=16.19 Y=31.07
Ascent Rate: 1100 feet per minute
Descent Rate: 950 feet per minute
Altitude: 5205 feet
Predicted Landing Site
Landing Point: 39.70013� lat.  -103.58603� long.
Grid: X=40.4 Y=37.2
Altitude: 4500 feet
Flight Time: 123 Minutes
Bearing: 75.7� True
Range: 25.0 Mi.
Actual Landing Site
Landing Point: 39.63201� lat.  -103.9316� long.
Grid: X=22.1 Y=32.5
Bearing: 76.4� True
Range: 6.073 Mi.
Difference from Predicted to Actual Landing Site
Bearing: 255.8� True
Range: 18.961 Mi.


Prediction History for EOSS-121 AVAILABLE HERE

EOSS Flight Day Frequencies:

All Frequencies tentative until 7 days prior to flight

Global Frequencies

EOSS-121 Balloon Frequencies

  • Beacon
  • APRS
    • 144.340 MHz
      • ID: AE�SS-11
      • DIGI: EOSS
      • Node: BALNOD
      • APRS Time Slotted Every 30 seconds at 0:00 and 0:30
      • Telemetry once a minute
        • power up at 58 seconds past the GPS minute to properly slot telemetry
      • Sample Data

Radio Coverage:

  • Green, you should be able to work the payload systems.

  • Red, is the border of the received signal. Red appears jittery because it is depicted topographically. Thus, the red dots on the eastern half of the map but well within the maximum distance show hilly terrain behind (east) which reception is not possible.

This is a generic 95,000 ft ASL coverage map for flights that depart from the vicinity of our launch site. Flight day coverage may vary depending on upper air winds.

Flight Systems:


Balloon Manufacturer Kaysam
Balloon Type latex
Balloon Size 3000 gram
Payload 25.6 lbs.
Free Lift % calculated at fill
Ascent Rate 1100 fpm estimated
Descent Rate 950 fpm estimated
Parachute 10 ft
Peak Altitude determined after flight
Launch Conditions calm


Payload Configuration:

Tracking and Recovery Info:


Location X Y
Last Chance 40 40
Touchdown (see Prediction Page)


Tactical Callsigns

Tactical Callsign Name Notes
Alpha N0MPM and WG0E Mike and Colin Tracking and Recovery Coordinator
Bravo KC0UUO Rob with KJ  
Charlie KC0VJE Louis  
Delta KB0YRZ Chris  
Echo WB0DKT, KC0ZIE, KC6HXM Glenn,  Darren, Sam  
Foxtrot N0NDM and W0CBH Larry and Benjie  
Golf KB0QQW Chris and Caleb  
Hotel WA0GEH Marty  
Ground AE0SS Nick Ground Station


Internet Gateway Stations:

as seen on Findu.Com

For AE0SS-11

  • K0YG-3 - Mark Patton, Foxfield, CO
  • KB0TVJ-3 Russ Chadwick, Boulder, CO
  • KC0UUO - Rob Wright, Mobile T&R Station
  • N0EB-1 - Richard Beggs, Thornton, CO
  • N0PSJ - Christopher Holmes, Arvada, CO
  • WB0BLV - Leroy Sublett, Colorado Springs, CO
  • WY0F - Jack Barnard, Grand Island, NE

EOSS wishes to express our sincere appreciation to the stations above who iGated the balloon APRS telemetry onto the internet. You have all i-gated before but did you know I publish predictions for i-gates? I keep a list of everyone who has ever i-gated an EOSS balloon flight. You're all in the list so if you're wondering when the balloon will pop up over your horizon, check out this page for future flights.  Currently predictions are being made for 28 i-gates.

We are relying heavily on real time position information available on the net to allow the FAA controllers to have up to the minute location data to assist them in air traffic control.

Redundant stations for the balloon iGating provide excellent coverage. If you are able to iGate we invite you to join the Internet Gateway Team. Contact me ( to be put in touch with the coordinator. By joining the team, you are giving peace of mind to the iGate coordinator for that flight. He knows you'll be there and he can rely on you.

Naturally, anyone can iGate data onto the net and even if you aren't a member of the team we will welcome your contribution to the internet based tracking effort. If you callsign appears on the log, you'll be shown as a contributing station as those above are.

Having more than one station covering each APRS beacon means that should a station drop out momentarily, the others can often maintain the data flow.

Thanks again guys! The FAA (and EOSS) are very grateful for your assistance in this endeavor.

Future I-Gaters:

Check out the EOSS I-Gate page for information on how to participate and why we need you.

Current I-Gate Stations:

Guys, the prediction program used to determine the track of the balloon prior to flight can now output a prediction for the Rise, Closest Approach or maximum elevation, and Set of the balloon for each of your stations. I have posted a prediction page for stations that I have been able to discover geographic coordinates. See the I-Gate prediction page for an example. The page will not be updated daily, however, it will be updated the evening prior to flight for I-gate planning purposes.

I have often been asked by iGaters when they should expect to either start receiving signals (AOS) or expect to see those signals disappear (LOS). This prediction page should answer all those questions for you.


  • Colorado University - Space Grant Consortium - DemoSats

One rover 100% good deployment, a second almost made it out of its garage. Look for videos at some point in the future.

note: customers are welcome to submit detailed synopses of their flights or web links to their own web sites.


Launch Site

Flying - From the ground looking up

Recovery Area



Reports of video taken as rovers exited their garages. "Luckily", we flew a quick ascent and the payload systems returned to the ground ahead of schedule. Timers delayed the deployment of rovers allowing T&R teams and students to be on scene when their babies woke up and crawled about the countryside.



Spread Sheets

Mapping Files


by Rick von Glahn, N0KKZ