EOSS-355/356/357 Metro State University Intro2Space & CU-Boulder Gateway to Space - Recap

On Sunday, 21 April 2024, three Lite (Exempt) balloons were launched from Deer Trail School in Deer Trail, Colorado.  Weather was cloudy, with a temperature of 32 degress in light Southeast winds.

EOSS-355, the first balloon, was for Metro State University Intro2Space Program, was a 3000 gram balloon launched at 0718 (ALL TIMES MDT) and ascended to 109,842 feet altitude when it released at 0847.  It landed at 0934 near Mt Pearl, CO at 38.9567 North, -102.7625 West.

EOSS-356, the second balloon was for the CU Gateway to Space Program, was a 1500 gram balloon launched at 0739 and ascended to 90,576 feet altitude when it released at 0850.  It landed at 0934 near Mt Pearl, CO at 38.9375 North, -102.9542 West.

EOSS-357, the third balloon was for the CU Gateway to Space Program, was a 1500 gram balloon launched at 0809 and ascended to 89,890 feet altitude when it burst at 0850.  It landed at 1002 near Mt Pearl, CO at 38.9527 North, -102.9959 West.

All payloads were sucessfully recovered in the field by the Students who built them.

 Link for EOSS mileage reimbursement  https://forms.gle/qJjy47iTHF5ywDPJ6

Original Announcement: 
  • 04-20-2024Payload Plans Rev F posted
  • 04-20-2024Tracker List UPDATED- WAØGEH
  • 04-19-2024Note Note! Due to deteriorating weather on Friday night/Saturday morning, the launch has been changed to Sunday 4/21/2024!

This is two 3000g balloons or one 3000g balloon and two 1500g balloons. One 3000g balloon is for MSU Intro2Space and the one 3000g balloon is for CU-Boulder Gateway to Space. If the skies are cloudy, the MSU 3000g balloon will fly with an Exempt payload string and the CU-Boulder balloon will be split into two 1500g balloons as follows:


Event Date: 
Saturday, April 20, 2024 - 00:00 to 23:45
Flight Coordinator: 
Launch Site: 
Punkin Center X=30, Y=20. Grid Test N 38.00, W 103.00 = X 67.5, Y 30.3

EOSS-355 Heavy

This is an Non-exempt payload string flown under a 3000g balloon for Metro State University Intro2Space students.

Balloon Type: 
Totex 3000g Latex
12 ft Rocketman with Remote Release Baker
144.905 MHzKC0D-1Remote Release/DFSecondary Beacon
144.340 MHzAE0SS-3APRS/Digi EØSSXPrimary Beacon Timeslotted 0:01 & 0:31
Payload Plan: 

EOSS-356 Heavy

This is a Non-exempt flight of a 3000g balloon carrying student-built payloads for University of Colorado - Boulder's Gateway to Space program.

Balloon Type: 
Totes 3000g Latex
12 foot Rocketman with Wireless Release Adam
144.340AEØSS-2DiscoveryJP02 APRS/DigiTime Slotted 0:11 & 0:41
145.535KCØD-2JPN-06 APRS/DF/Release
Payload Plan: 



EOSS Preflight Net @ 7 PM Mountain Time the preceding night:


The preflight net is hosted on the Fun Machine linked system https://www.we0fun.com/  

EchoLink *CANONCTY* conference and on the TGIF DMR Network Node: 1997 Talkgroup 815

Denver area Frequencies: 

    • 449.225 MHz (-5 MHz Offset, 141.3 Hz CTCSS) Mt Thorodin
    • 448.150 MHz (-5 MHz Offset, 141.3 Hz CTCSS) DIA
    • 449.975 Mhz (-5 MHz Offset, 100 Hz CTCSS) Westcreek
    • 447.525 MHz (-5 MHz Offset, 146.2 Hz CTCSS) Devils Head   

Back up Pre Flight Net Frequincies

        • 146.940 MHz (-600 KHz Offset, 103.5 Hz CTCSS) Rocky Mountain Radio League (RMRL) Repeater if the RMHAM machine is down
        • 146.640 MHz (-600 KHz Offset, 100.0 Hz CTCSS) Denver Radio League (DRL) Repeater will serve as a backup to the backup repeater 

Flight Day:
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

        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)

Digital Mobile Radio (DMR):

The decision as to which talkgroup use will be made by the EOSS RF Coordinator on a per flight basis.

  • Rocky Mountain Wide Network – Talk Group 700 - Rocky Mountain Ham Radio has approval to the use "Wide" for flight operations.
  • Central Colorado Regional Network – Talk Group 720 - On occasion, EOSS may use the Central Colorado Regional Network (Talk Group 720).

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

2M Direction Finding Frequencies:

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


Tactical Calls: 
TacticalCall SignNameNotes
AlphaWAØGEH, KFØPCWMarty, Doug L.
BravoW9CN, NØJPSMike, John Post Breakfast
CharlieKFØOGS, K5CFR, KN6OJJCU ARC: Wes, Charlie, NeetiPost Launch
DeltaKØSCC, KØBRAStephen, DougPost Launch
EchoKCØRPS, N1GUMJim, PeterFlight Coordinator
FoxtrotKCØL, K5PUPJohn, EileenFlight Coordinator - Texas
GolfK0NKK, N1GUMNancy, PeterPost Launch
Ground StationN2XGL, K5JKJeff, Tom, Randy
JulietNØNDMLarry Post Launch
KiloKEØUWC, KFØMBR, KFØNLQGlenn, John, Ann Post Launch
ZuluKEØZJVMatt, w/ CU StudentsPost Launch
HotelN3RJORandy Owens w/ MSU StudentsPost Launch
TR Breakfast: 
Tracker Breakfast will be at 6 AM at the Limon Flying J Truck stop IHOP.