EOSS Upcoming Flights
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04/04/2026 - 00:00 to 23:45
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04/11/2026 - 00:00 to 23:45
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04/18/2026 - 00:00 to 23:45
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05/02/2026 - 00:00 to 23:45
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05/04/2026 - 00:00 to 23:45
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05/09/2026 - 00:00 to 23:45
EOSS-381 &382 Colorado Space Grant Consortium Summer Launch - Recap
This will henceforth be known as the EOSS 381/382 Fog, Battery, Brakes, Fork Flights. Two 1500g balloons were launched from the Limon Soft Ball Fields on Saturday, August 2, 2025.
Students started arriving around 4:00 a.m. By 5:00 a.m., tables were up, the weigh-in had started, and we were watching the beautiful starry night sky with a few falling stars. The EOSS Team began arriving, and the FOG started rolling in. The payloads were strung as two 1500g balloons, with hopes we could combine them to fly one 3000g balloon. We put the launch "on hold" around 7:30 because of the fog. The FAA was notified, and we agreed to meet back at the launch site at 8:30 am to determine next steps. The fog was lifting, and we could see 5 miles. After calls to the weather forecasters and the FAA, we launched two 1500g balloons between 9:00 and 9:30. Trackers, as usual, located the landowner who permitted us to retrieve 381. The landowner took 2 EOSS members out in the deluxe 4-wheeler to retrieve 382.
EOSS member mileage reimbursement submission here
EOSS-381 - KC0D-1 Burst Altitude:94809 Ft
Landed: 39.02892, -103.11552
EOSS-382 - KC0D-2 Burst Altitude:96821 Ft
Landed: 39.02485, -103.15799
A huge thank you to everyone involved in Saturday's activities. With everything that was happening, we had a successful launch and recovery.
FOG-rolled in at 6 and out at 9
BATTERY- auxiliary battery in the Van almost caught fire
BRAKES- Alphas' brakes locked, and Mike ran Tracking & Recovery from the picnic tables at Hugo's Loaf & Jug
FORK- Payload retrieval - go to the fork in the road and wait for further instructions (see the photos below)
Recap Gallery:
Original Announcement:
This is one 3000g balloon or two 1500g balloons carrying student-built payloads from a variety of Colorado colleges participating in the Colorado Space Grant Consortium.
The launch site has been moved from Deer Trail to the Limon Softball Fields. This is because of summer winds winding back into DIA airspace.
- 06-19-2025Payload Plans Rev A posted
- 07-10-2025Payload Plans Rev B posted
- 07-30-2025Payload Plans Rev C posted
Predictions are shown at www.eoss.org/predict. Scroll to the correct date and launch site. Two weeks before the flight, predictions will start updating on a 24-hour basis.
Please indicate your ability to participate (or indicate if you cannot) on this flight here: https://forms.cloud.microsoft/r/Jnn9F8BM8G . You can look at the participation spreadsheet (if you are logged into Teams) here:
If clouds are greater than 5/10ths, the payload string will be split and flown on two 1500g (exempt) balloons as follows:
Event Date:
Saturday, August 2, 2025 - 00:00 to 23:45
Flight Coordinator:
KCØRPS
Launch Site:
Flights:
EOSS-381 Heavy
Carrying Colorado Space Grant Consortium student payloads
Balloon Type:
Totex 3000g Latex
Parachute:
12 ft Rocketman with Remote Release Charlie
Beacons:
| Frequency | Callsign | Type | Notes |
|---|---|---|---|
| 145.710 MHz | KCØD-3 | Remote Release/DF | Secondary Beacon |
| 144.340 MHz | AEØSS-4 | APRS/Digi AEØSS | Primary Beacon Timeslotted 0:13 & 0:43 |
Payload Plan:
FrequencyList:
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:
Repeaters:
• 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:
| Tactical | Call Sign | Name | Notes |
|---|---|---|---|
| Alpha | W9CN | Mike Pappas | with Jeff Deaton N0JD |
| Bravo | Kb0yrz | Chris Krengel | with Zach Price KF0LDI |
| Charlie | N0JPS | John Spainhower | with Jeremy Cook |
| Delta | K0sCC | Stephen Meer | |
| Echo | KE0UWC | Glenn Reker | with John KF0MBR |
| Foxtrot | NØMM | Doug Leber | |
| Golf | K0NKK | Nancy Koos | student escort |