EOSS Upcoming Flights
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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
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06/20/2026 - 00:00 to 23:45
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10/31/2026 - 00:00 to 23:45
EOSS-374/375 Gateway to Space - Recap
Summary:
Two 1500g balloons were launched with exempt payload strings on Saturday, May 3, 2025 from Limon Colorado. This was the third attempt to launch the Gateway to Space payloads, delayed by weather. All class payloads flew, but sadly some students could not attend the launch because of final exams. The balloons flew as follows
- EOSS-374 - launched at 7:58am. The students watched the balloons from the launch site up through burst. The balloon burst at an altitude of 89,886 ft, and landed approximately 15 miles south of the launch site east of north/south Road 24 and east/west Road 2D (38.8808, -103.6035). This is northeast of Punkin Center. The walk in to the landing site was 1.2 miles each way.
- EOSS-375 - launched at 8:19am, burst at an altitude of 87,363 ft and landed within 0.75 miles of the other balloon (38.8913, -103.6068). The walk in was 1.3 miles each way.
EOSS member mileage reimbursement submission here
Recap Gallery:
Original Announcement:
Notice of Change: The launch site has been relocated to Limon Colorado Softball Fields, located 2 miles south of Limon on Highway 71. Maps are available here.
The Gateway flight is a 'GO' for Saturday, May 3, 2025. Two Lite balloons will be launched at 0800 and 0820 MST. Predictions are shown at www.eoss.org/predict. Scroll to the correct date and launch site.
Updated EOSS participation link for 5/3/2025: https://forms.office.com/r/ZGggXcDUMh . If you are signed into MS Teams, you can view the results spreadsheet here: EOSS Flight Day _May 3rd, 2025 (2) 1.xlsx
Scrubbed flight on April 26, 2025: Unfortunately the Gateway to Space flight was not possible on Saturday, April 26, 2025 from Windsor, Colorado. Ground fog limited visibiltiy, preventing a safe launch. After a 1.5 hour delay, conditions had worsened. In addition, reports and evidence of a GPS system degredation reduced the likelyhood of successful tracking and recovery of the two balloons that were to be launched. Pictures posted here. The launch is postponed one week until Saturday, May 3, 2025. The launch site will be determined and posted here.
EOSS member mileage reimbursement submission here
- 05-02-2025 Payload Plans Rev F posted
- 04-30-2025 Payload Plans Rev E posted
- 04-25-2025 Payload Plans Rev D posted
- 04-25-2025 Launch site updated
- 04-15-2025 Updated EOSS participation links posted
- 04-15-2025 Payload Plans Rev C posted
- 04-12-2025 Payload Plans Rev B posted
- 04-10-2025 Payload Plans Rev A posted
Event Date:
Saturday, May 3, 2025 - 00:00 to 23:45
Flight Coordinator:
KC0RPS
Launch Site:
Flights:
EOSS-374 Lite
This is one 1500g balloon
Balloon Type:
Totex 1500g Latex
Parachute:
12 ft Rocketman with Remote Release Adam
Beacons:
| Frequency | Callsign | Type | Notes |
|---|---|---|---|
| 144.905 MHz | KC0D-1 | Remote Release/DF | TOP, Secondary Beacon |
| 144.340 MHz | AE0SS-3 | APRS/Digi AEØSS | BOTTOM, Primary Beacon, Timeslot 0:20 & 0:50 |
Payload Plan:
EOSS-375 Lite
This is a 1500g balloon
Balloon Type:
Totex 1500g Latex
Parachute:
12 ft Rocketman with Remote Release Charlie
Beacons:
| Frequency | Callsign | Type | Notes |
|---|---|---|---|
| 145.710 MHz | KC0D-3 | APRS/DF | TOP, Secondary Beacon |
| 145.535 MHz | AE0SS-4 | APRS/DF | Flight Qualification |
| 144.340 MHz | AE0SS-2 | APRS/Digi DISC | BOTTOM beacon, timeslotted :08 & :38 |
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
Skyhub repeaters linked to the primary FM repeater (449.450 MHz):
- Limon (Cedar Point) - 447.650(-) MHz, 103.5 Hz
- Hugo - 447.150(-) MHz, 103.5 Hz
- Firstview - 447.600(-) MHz, 103.5 Hz
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, NØJD | Mike, Jeff | T&R Coordinator |
| Bravo | KBØYRZ | Chris | T&R Backup |
| Charlie | KCØRPS, KFØNLQ | Jim, Anne | Flight Coordinator, T&R |
| Delta | KØSCC, NØJPS | Stephen, John | Flight String Management & T&R |
| Echo | KEØUWC | Glenn | T&R |
| Foxtrot | NØNDM | Larry | Balloonmeister |
| Ground Station | N2XGL | Jeff, Randy | Ground Station, FAA Coordination |
| Golf | KØNKK | Nancy | Flight String & T&R |
| Hotel | KEØZJV | Matt | Gateway to Space |
TR Breakfast:
Limon IHOP in the Flying J truck stop at 6:30 am