Recap of EOSS-65

LAUNCH DATE: April 19, 2003
LAUNCH TIME: 08:58 am MDT, 14:58 UTC
LAUNCH SITE: Windsor, CO (directions)

Green = actual track
Purple = predicted ascent
Red = predicted descent

Launch Site - Windsor
Launch Point: 40.4737� lat.   -104.9635� long.
Ascent Rate: 1000 feet per minute
Descent Rate: 1100 feet per minute
Altitude: 5020 feet
Predicted Landing Site
Landing Point: 40.7336� lat.  -104.6164� long.
Altitude: 4500 feet
Flight Time: 125 Minutes
Bearing: 45.3� True
Range: 25.6 Mi.
Actual Landing Site
Landing Point: 40.5564� lat.  -104.8293� long.
Bearing: 50.9� True
Range: 9.1 Mi.
Difference from Predicted to Actual Landing Site
Bearing: 222.4� True
Range: 16.6 Mi.


  • HF Net during Flight
    • 7234 KHz
  • APRS
    • 144.340 MHz
      • Callsign W5VSI-11
      • Digi EOSS
      • Node BALNOD
  • APRS
    • 145.600 MHz
      • Callsign KC�JHQ-11
  • Beacon
    • 147.555 MHz
  • Tracking and Recovery Operations
    • 449.450 MHz 103.5 Hz tone RMRL Repeater
    • 146.550 MHz simplex (same simplex for field and launch ops)
  • Simplex at Launch Site
    • 146.550 MHz (same simplex for field and launch ops)

If an EOSS payload is highlighted, there is a link to an information page about that payload.

Payload Configuration:

Several Colorado University Space Grant Consortium Payloads:

Flight System:

Balloon Manufacturer Scientific Sales (Japanese balloon name coming soon)
Balloon Type latex
Balloon Size 1200 gram
Free Lift % 25%
Ascent Rate  1221.1 fpm calculated
Descent Rate  ~ 4000 fpm (adjusted to sea level) calculated
Peak Altitude 93,010.5 ft. max packet
Launch Conditions winds 15 Knots from the north

See NOTES below regarding payload train configuration

Tracking and Recovery Grid:

Here is the grid layout for EOSS-65

Location X coord Y coord
Greeley 17 35
Woodrow 75  4.5
Buckingham 55 48
Last Chance 75 -12.5
Launch 2.56 38.07
Pred Landing 17.6 51.4

Grid Calculator

  • Western Intersection of State Rd. 71 (N/S) with
  • County Rd. 14


  • 40� 36.615' N
  • 103� 40.614' W
  • Grid X = 70
  • Grid Y = 47.5

General Radio Footprint



James Cizek, KI�KN and Lee Inman, K�QED did the honors of iGating the packet APRS telemetry onto Thanks guys. Without you the FAA wouldn't be nearly the happy campers they are, now that they can watch the balloon systems via the web.


I'm posting audio of the entire flight's Tracking and Recovery effort. If you have never participated in a balloon launch you might find it interesting.

The links download MP3 files of the audio. It is quite compressed but still clear. There is a high background noise when no transmissions take place (AGC) :-(

93 minutes of audio in approximately 10 Mbytes of data spread across these 5 files.

  • Preflight - 1.1 MBytes, 9:26 minutes/seconds of pre liftoff audio
  • Ascent Phase One - 3 Mbytes, 25:46 min/sec of ascent
  • Ascent Phase Two - 3.3 Mbytes, 27:58 min/sec of further ascent traffic
  • Descent - 1.5 Mbytes, 12:21 min/sec The entire descent phase of the flight. It was REALLY moving.
  • Search - 1.9 Mbytes, 16:14 min/sec The entire search sequence from touchdown to the first visual sighting



Plain Text Log File

Spreadsheet File


  • Ascent rates. With a fouled parachute we achieved a pretty remarkable descent rate.

T&R Recap

Benjii Campbell, W�CBH

Well, I for one am tired and bummed. I have gone from the "Lawn Chair Larry" award on the last flight to the Largest Bearing Error on this flight. Wow, what fun! (NOT)

The wind was incredible. it was blowing steadily at over 20 mph at our bearing location.

We parked next to a large dumpster to get out of the wind, and then couldn't get good bearings. I am definitely going to change my hunting antenna after this one. I will not park next to a dumpster again either. We were about 20 yards from it, shouldn't have affected us that much.

I got better bearings from Mark's beacon with the enclosed antenna than the old, spin in the wind antenna beacon. Mike Morgan tried his Doppler, and got one good bearing out of the bunch. We should have used his instead of a consensus bearing, but that one was still over 15 degrees error or thereabouts.

Nick's program worked well except for the balloon x value on the grid locator. He is working on that, should be interesting to find out what and why there.

It was fun to watch the plots of the balloon location, even if it was 40 some miles east of the true location.

Flight Related Info