EOSS-238/239/240 STEM Flight

This will be exempt balloon(s) supporting STEM programs in Colorado. Currently we have the following programs onboard:

These flights are scheduled to launch at 0700 (and every 15 minutes thereafter) on Saturday March 18, 2017. We have a number of launch sites from which to select, based on the predicted flight path dictated by the winds. Currently the best launch site appears to be Deer Trail, Colorado. Click on the link for maps and directions. As we get closer to the launch wind predictions may change and the launch site may have to change as well. Watch this website for updates. The current prediction is shown on the figure below (blue is going up, red is coming down).

Starting two weeks before the launch this flight path prediction will be updated daily. If the launch site is likely to change, it will be discussed then.

 Click on the Payload Plans below to see the details of each balloon.

Flight Coordinator: 
Event Date: 
Saturday, March 18, 2017 (All day)
Alt Launch Date: 
Sunday, March 19, 2017
Launch Site: 


An exempt balloon for Colorado Springs School

Balloon Type: 
1500g Totex latex balloon
5.8 ft orange and white nylon parachute with spreader ring
144.340 MHzKCØD-14APRS/Digi/DF EOSSTimeslotted at 0:00 and 0:30 seconds
147.555 MHzAEØSSCW/cutdownDF Beacon
145.360 MHzKØSCC-9APRS BeaconSecondary Beacon


An exempt balloon for Chatfield High School

Balloon Type: 
1500g Totex latex balloon
9 foot Rocketman High Altitude Balloon Payload Recovery Parachute
144.340 MHzAEØSS-8APRS BeaconTimeslotted at 0:10 and 0:40 seconds
144.950 MHzKEØBMV-11APRS/DF BeaconSecondary Beacon


An exempt balloon for the National Defense Industrial Association, coordinated by National Space Science & Technology Institute.

Two Payloads weighing a total of 5 pounds maximum. These payloads will contain physics and engineering experiemtns from High School students, 4th, 7th, and 8th graders.

Updated Payload Plan

Balloon Type: 
1500g Totex latex balloon
8.5 ft circumference Sphereachute with cutter and fast release
145.750 MHzKCØD-12APRS/DF/CutterSecondary Beacon
144.340 MHzKCØUUO-11APRS/DigipeaterTimeslotted at 0:20 and 0:50

Preflight Net:

  • 147.225 MHz CRA Repeater (107.2 Hz Tone) 8 pm MDT preceding night
  • 146.940 MHz (103.5 HZ Tone) RMRL Repeater if the CRA machine is down
  • 146.640 MHz (100 Hz Tone) DRL will serve as a backup frequency

Recovery Operations:

  • 449.450 MHz RMRL (103.5 Hz Tone)
  • 448.225 MHz (141.3 Hz Tone) Testing… PL verified 7/2/14
  • 446.100 MHz Field Simplex (Balloon #1)
  • 446.150 MHz Field Simplex (Balloon #2)
  • 446.200 MHz Field Simplex (Balloon #3)
  • 146.550 MHz Backup field simplex
  • 446.275 MHz Car drive-out frequency

Launch Site Simplex: 446.050 MHz

HF - Possible ops: 7.235 LSB

Tactical Calls: 
TacticalCall SignNameNotes