Recap of EOSS-50

All reports, corrections and additions to this recap are welcome.

LAUNCH DATE: April 21, 2001
LAUNCH TIME: 15:45 UTC - 09:45 MDT
LAUNCH SITE: Windsor, Colorado, (Directions Here)

Leave Denver Colorado on I-25 north bound. Proceed to the Windsor exit (Exit Number 262). Proceed East on State Road 392 approximately 1.3 miles to county road 3. Take county road 3 south a few hundred yards. The launch site will be on the east side of the road. Numerous vehicles with antennae will undoubtedly mark the spot.


  • 40.4744 Degrees N. Latitude
  • 104.9628 Degrees W. Longitude

Landing Site Coordinates:

We have recovered the packages. They were found in a field by the property owner. And, he graciously followed the please return instructions on the payload and contacted Pioneer Astronautics. Currently I only have a very rough latitude, longitude pair for the recovery site. It is essentially the mailing address for the land owner. Perhaps we will obtain better coordinates in the future.

  • 41� 54.3' N. Latitude
  • 103� 05.53' W. Longitude

PRIMARY INTEGRATOR: Pioneer Astronautics, Dr. Robert Zubrin [KC�IIK], Gary Snyder [N7QAM], Mark Caviezel [KC�JHQ], �Mars Micro Balloon Probe�.


  • This is the seventh of many planned EOSS flights for 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.
  • Additionally, two 600 gram �Grape� drag balloons will fly to help stabilize
    the payload on decent while deploying the micro balloon.  This experimental
    drag balloon concept will be deployed on Mars missions if successful.

Net Frequencies:

Preflight Foxhunter Net:  

  • 147.225 MHz Colorado Repeater Association, 8:00PM the preceding night

Launch Site: 

  • Simplex 146.550 MHz

HF Net: 7.235 MHz, Bruce NA0BR

Tracking Team:

  • 449.450 MHz Rocky Mountain Radio League (RMRL) (pending approval)
  • 146.58 MHz Simplex Field Frequency

Payload Frequencies:


  • Callsign: KC�IIK-11
  • 145.600 MHz - $GPGGA NMEA Sentence


  • 147.455 MHz CW tone and carrier


  • 426.250 MHz AM

Pioneer Astronautics RECAP

Mark Caviezel provided an excellent recap of the flight from Pioneer's perspective.


Hi everyone;

The EOSS had two flights this past Saturday, the 21st of April, 2001. We did work both flights with Kevin Shoemaker, Pete Goldman, Robert Slate & another fellow who's name I don't have present. Also Eric Richards made a cameo appearance.

From a DSES viewpoint, the exercise generally went real good with good to excellent ATV reception until the ATV battery died somewhere near the state line not to long after burst. (An EOSS inspection revealed a battery failed when it should not have.)

From a EOSS viewpoint, the results were mixed. The first flight, EOSS-49 accomplished it's mission and was recovered. The second flight, EOSS-50 made altitude, lost telemetry at burst at 104,000 ft and we lost the beacon about 20 minutes from touchdown and it has not been recovered. The tracking and recovery teams seem to have never heard the beacon.

Two errors prevented this from being a perfect flight. The first was that although the video is at 426.250 MHz the radio needs to be tuned to 430.750 MHz +/- 1 MHz. I understand that this is due to the way the ICOM tunes the video. We actually need to tune to the audio carrier frequency which is about 4 MHz higher than the video. We knew this before launch but did not do so until after launch so we missed the launch.

The second error was an (about) 10 degree bearing error from the GPS prediction to actual. The balloon location is received via telemetry and Slate moves the cursor on his Garmin 3 GPS to that location. The Garmin then shows a bearing. It worked very well on EOSS-47 but not on this flight. The Garmin is set for true, not magnetic and the dish selsyns are correct. The Garmin bearing would be say 53 degrees when the target was found at +/- 42 degrees. No cause has been determined yet.

I suppose a third error could be mentioned where Slate started tearing down the gear before the second flight ended. Sorry Kevin...

The main VCR worked, but not as well as the cam-corder. If not for the cam-corder, the video tape quality would have lowered the success level. I believe a head cleaning is in order. Incidentally, video failures on the last two flights, #47 & 48, seem to have been EOSS problems, not DSES failures. We do need to get audio on the VCR tape, preferably packet & tracking/recovery.

From a hardware viewpoint, we did pretty good. Wind was again an issue but both a lower gear ratio and working and controllable brakes should take care of that.

We also installed an old RG-8U cable thru the wavequide on the upper pylon from the feed to the base of the tower. This is to provide both DC power to the feed and to provide a ground for the feed point hardware. The waveguide also needs to be grounded at both ends. Unless someone has a better idea, we're going to terminate the RG-8U at the box at the feed box with an RG-259 bulkhead connector. We did not use this cable on this flight.

At least one of the VF drives does generate some hash on the video, probably the one sitting next to the VCR. A PLC in the shack did not but it wasn't wired to anything. Since both VF drives will be installed in a shielded box inside the tower this situation should be resolved.

Pete verified that his controller still operates the elevation drive via the PC and is going to wire the new azimuth drive to it also. At that time PARATRAK will be back in service.

After the ATV signal tracking was complete and the RG-8U was installed we used the dish to track the 2 meter beacon of EOSS-50 with the 70cm hardware. We were successful and the feedpoint pre-amp did help, but I hope that 2 meter hardware would perform better.

Robert Slate, N0TQN


Plain Text TNC Log file

Spreadsheet of TNC data