LAUNCH DATE: Sunday - October 1, 2000
LAUNCH TIME: 15:17 UTC - 09:17 MDT
LAUNCH SITE: Circle 8 Ranch (see map for directions)

note: the touchdown location is somewhat nebulous. After having recently (11/14/2005) extracted some data from an APRS+Plus log file I believe it is really:

  • 39.0395 N
  • 103.7465 W

These figures also line up with the last position of W5VSI in the black trackline below.

Black Line = APRS track
Blue Dots = Predicted Ascent Path
Red Dots = Predicted Descent Path

Balloon Track for Windows                                Version 1.6.5
Flight Recap
Sunday, October 01, 2000           EOSS-44          DEN_00_10_01_1200Z.dat
11:04:32 AM                    Circle 8 Ranch                   eoss44.ini
Winds DataFile
Station: DEN
Date: 1200Z  1 OCT 00
DataFile Status: Errors in Source File
Intact Records: 38
Corrupt Records: 2
Launch Site - Circle 8 Ranch
Launch Point: 39.3347� lat.   -104.5469� long.
Ascent Rate: 1112 feet per minute
Descent Rate: 1017 feet per minute
Altitude: 6632 feet
VOR Station - Falcon(FQF)
Latitude: 39.6867� lat.
Longitude: -104.6233� long.
Magnetic Offset: -10.0� from True Degrees
Maximums Enroute
Distance to LOS: 418.7 Mi.
Maximum Range: 59.3 Mi.
Maximum Winds: 92.1 mph from 315� at 39,379 feet altitude
Burst Data
Burst Point: 39.1804� lat.  -103.8412� long.
Burst Time: 85.8 minutes
Burst Altitude: 102,000 feet
Burst Bearing: 105.5�
Burst Range: 39.2 Mi.
Predicted Landing Site
Landing Point: 39.0773� lat.  -103.4898� long.
Altitude: 4873 feet
Flight Time: 124 Minutes
Bearing: 107.1� True
Range: 59.3 Mi.
Actual Landing Site
Landing Point: 39.0615� lat.  -103.8225� long. (probably incorrect, see above)
Bearing: 115.7� True
Range: 43.1 Mi.
Difference from Predicted to Actual Landing Site
Bearing: 266.6� True
Range: 17.9 Mi.


  • The �Mars Micro Balloon Probe� which will place a series of balloons in the Martian atmosphere. The objective of this flight are to test and develop inflatable gases from compounds that are normally liquids at Standard Temperature and Pressure (STP). The Mars surface pressure is simulated at 100,000 feet above sea level, thus the experiment on an EOSS balloon. This experiment will attempt to inflate balloons using various compounds. This will also permit a test of the deployment canisters required on Mars.

    On this flight, the deployment will take place during the descent phase. In order to simulate the descent rate expected at Mars, there will be three balloons inflated and attached to the payload train to provide drag during the descent phase. At maximum altitude, the 3000 gram balloon will be cut away, the three drag balloons will then provide a means to slow the descent from maximum altitude. Once the payload train reaches terminal velocity (30 to 50 meters per second) the Mars balloon deployment will begin. The entire payload train will then descend to around 30K feet at which point the three drag balloons will be cut away. The payload will descend to the ground slowed only by the parachute.

    The EOSS Shuttle II ATV camera will monitor the balloon deployment and inflation. Tune in for the excitement.


  • Pioneer Astronautics, Dr. Robert Zubrin, Dean Spieth, �Mars Micro Balloon Probe�.


  • Preflight Foxhunt Net 8 pm the night before flight
    • 147.225 MHz Colorado Repeater Association
  • Launch Site:
    • Simplex 146.550 MHz
  • Telemetry:
    • 144.340 MHz APRS, Temps in and out, housekeeping, generic navigation
  • ATV
    • 426.250 MHz NTSC video
  • Beacon
    • 147.555 MHz
  • APRS
    • APRS String on the output of the EOSS Shuttle II
  • Foxhunters:
    • 448.450 MHz Pikes Peak FM Association (pending approval)
    • 146.58 MHz Simplex Field Frequency
  • HF Net 7.235 MHz


From Larry, K0ANI

Well, EOSS-44 went off this morning (Oct 1, 2000) at 0917. This flight was a second flight to test inflation techniques for a possible Mars orbiting balloon. The theory being the atmosphere at 90 to 100 thousand feet is similar to that found on Mars. The attempt is to fill the Mars balloon with a liquid which will vaporize at that low atmospheric pressure. In this experiment, I believe methanol or wood alcohol was used. I didn't hear the outcome of the experiment, but the balloon to be filled was deployed.

In this experiment the balloon fill was to take place during decent. To slow the decent to small balloons were attached below the 3000 gram lift balloon. The two small balloon were to add drag and a small amount of lift to provide a slower decent rate than that seen after a normal burst of the lift balloon. Unfortunately, both small balloons burst during ascent.

The flight itself was interesting in that "Good old Shuttle II", which should have been retired some time ago, flew one more time. Tracking Shuttle II is becoming more and more interesting with its' cranky GPS sometimes working fine, other time showing the balloon in the next county.

Recovery went well. The payloads landed 43.2 miles at 116 degrees from the launch landing about 15 miles SSW of Limon, Colorado or about 20 miles NNW of the famous Punkin Center, Colorado.

EOSS-45 is due to fly in about two weeks. Stay tuned......

from Dean Spieth

This flight (EOSS44) was pretty much a disaster all around, but after the success of EOSS43 we can't complain too much. 

The flight should have been cancelled because the high surface winds made it impossible to weigh the lift of the main balloon as well as the small balloons. Unfortunately, all the balloons were obviously overfilled. The main 3000g balloon popped at 91kft, whereas the prior flight went to 107kft, and we should be able to go to over 110 kft with 12 lbs payload if we only filled them to 20% free lift (and still get 1000 fpm!). The two small drag balloons, 350g each, should have been 0.95m diameter at lift off with 100g of free lift, increasing to over 3 m at 100 kft - their burst diameter spec was 4.1 m, yet they burst below 90 kft. Kaymont assured us they should be OK despite their discoloration. Each small balloon should have only contributed 10% to the drag area of the main balloon. The shuttle GPS indicated 6700 ft elevation at liftoff, whereas preflight preparations assumed 5500 ft elevation which can contribute slightly to overfilling. I would like to know the actual elevation of the Circle 8 ranch.

The high surface winds and overfilling of the main balloon (estimate over 40% free lift based upon 1500 fpm ascent rate) caused quite a jerk at liftoff, so the camcorder shut down a few seconds after Merle and I let go. It was fully intact after landing, and had lots of battery life left. I have a few stills of the liftoff, taken from the ground, which show some very odd main balloon shapes, but I haven't scanned them in yet.

The HOBO data logger (less than one ounce) worked flawlessly again. The lowest pressure sensor data point was 0.308 volts, which corresponded to 91 kft based on EOSS43 data. It indicated coldest air temps of -70C consistent with radiosonde data taken that same day. Gary's (Pioneer) electronics box did not get below -20C this time. EOSS was able to record transmission signals from his box up to the burst altitude of 91 kft; however, his last GPS fix was at 75 kft (22817.7 meters), so if anyone has data from his GPS (145.6 MHz N7QAM) at higher altitudes we would like to know.

George, I believe, saw the descent. It would be nice to know if the parachute was fully opened at impact. Apparently the payloads were dragged upon landing on the ground, another reason not to launch on a windy day. By the way, I have an accurate weight on the "70 inch" orange chute plus its 18 inch ring; the value is 401 grams/454 g/lb = 0.88 lbs, not 1.2 lbs. I also verified this today with 400 grams of calibration weights.

That's all folks!



More comments are welcome for addition to this recap from Pioneer any chase team members or other participants.

Pictures are welcome. Please make them no larger than 640x480. It would be appreciated that they be JPEGed to 50% compression too if possible. But if they look bad with that compression, use your discretion. I'm trying to save download time in email. I often get dozens of pictures when I solicit like this.


Click this link for some Pictures from Tim Tonge


eos44tlm.zip contains:

  • Plain Text Tnc Log File = eoss44.txt
  • Street Atlas 8.0 map file = eoss44recap.sa8
  • APRS-Plus Log file = w5vsi.log

Ground Station TNC Log File = w5vsi_eoss44.log

Prediction data: