FLIGHT RECAP OF EOSS-34

LAUNCH DATE: April 25, 1998
LAUNCH TIME: 14:03 UTC - 08:03 MST
LAUNCH SITE: Windsor Colorado

• 40 deg 28.526" North Latitude
• 104 deg 57.678" West Longitude

TOUCHDOWN COORDINATES:

• currently unavailable

TRACK: 77 Degrees, Approx 51 Miles

PREDICTED TRACK: 77 Degrees, 57.5 Miles

FLIGHT EXPERIMENT: Systems Tests
PROJECT INTEGRATOR: EOSS

FREQUENCIES:

• Launch Site:
  • Simplex 146.550 MHz
• Telemetry:
  • 144.340 MHz FM (1 Watt output) - The Packet telemetry stream is in ax.25 format at 1200 baud and is readable in plain english for the most part.
• GPS (independent package - AA0P-11)
  • 144.390 MHz with EOSS digi on board
• ATV:
  • EOSS Shuttle Video - 426.250 MHz AM (1 Watt output) - NTSC video
• Foxhunters:
  • 449.450 MHz Rocky Mountain Radio League
  • 146.58 MHz Simplex Field Frequency

notes:

ATV:

• The Amateur Video Signals from the payload worked just fine.

Flight Recaps

Here are a series of pictures by Tom Isenberg, N0KSR

by Larry Cerney, N0STZ

• Well, the morning was not the best. With a very poor weather forecast for the weekend, I didn't expect to get the flight off. The day started with light rain in the early morning hours and there was some talk about scrubbing the flight. With a number of students from CU Boulder counting on the flight for data for their class, we pushed on to the launch site in Windsor CO and hoped for the best.

  We checked the local Doppler Radar and saw that the shower activity was from Denver south. The northern part of the state was clear of rain. This was confirmed as EOSS member headed north to drier roads and clearing skies. By the time we all had gathered at the launch site, it was just another "Beautiful Day In Colorado".

  The flight was in support of freshmen students at CU Boulder in Astro Engineering (?) who will be designing our satellites and space craft in the next century. The plan was to give the students a real time telemetry downstream with raw data of temperature and pressure as well as GPS data in NMEA sentences for them to decode and manipulate.

  The flight lifted off a few minutes after the planned 0800 launch time and with only a small problem with the still balky onboard GPS. GPS lost lock early in the flight, but came around and worked well the rest of the flight.

  The balloon burst at 84,000 feet, a little earlier then planned and landed a little short of the expected touchdown. The balloon traveled about 51 miles at about 77 degrees from the launch site and landed about five miles SE of Keota CO.

  Three teams of hunters, myself included, were able to get under the balloon on descent and watch the balloon land in a field about 100 yards off the road we were on. Balloon flights just don't get any better then this one. We took pictures, picked up the payload and beacons and were back in Greeley CO for lunch by 1130.

  Great job by all those involved!

  Next flight, EOSS-35, in Laramie, WY and a try for a high altitude record (for us).

Another View of EOSS-34

Author : Slate, 5 May 1998
Subject : EOSS-34 flight of 25 April, 1998

On the 25th of April the Edge of Space Science (EOSS) group launched their 34th mission from a site about 3 miles west of Windsor Colorado on a flight that took it 48.6 miles at a bearing of 74 degrees to a point between the town of Keota and Hwy-14 in the Pawnee grasslands of northern Colorado.

The DSES tracked this flight with the upper dish from the launch at 26.7 miles, 32 degrees to touch down at 70.8 miles, 60 degrees recording alternately the APRS (automatic packet reporting system?) package and shuttle telemetry. The live 426 MHz ATV (amateur television downing) also was recorded.

The purpose of the DSES involvement was to test a new elevation drive, generator operation and to practice tracking. Also a new antenna feed was used for the first time. For the EOSS we hoped to provide a solid video copy of the ATV signal.

The results are as follows:

1. Although the bearing was known so the dish could be aimed the ATV signal could not be picked up while on the ground. This was expected due to terrain and curvature of the earth resulting in the launch site being over the horizon.

   The ATV down-converter having a VFO with poor indication of frequency did not help. Using the signal generator to center the VFO was not successful in the video mode. Local broadcast and other ATV signals added to the RF confusion.

   Just the same AOS (acquisition of signal) of the video was made shortly after launch as soon as the balloon cleared the radio horizon and LOS (loss of signal) occurred less than 1 minute before touchdown or at about a balloon altitude of about 1000 feet. For the duration of the flight the video quality was excellent unless disturbed intentionally by moving the dish or VFO or if neglect allowed the balloon to move out of the beam. Signal strength was never an issue.

   Referring to the GPS telemetry the maximum altitude achieved was about 85,000 feet. The maximum altitude achieved was lower than desired as the balloon apparently failed early. Dish angles at burst were not recorded so a math solution or confirmation is not available.

2. The new helical feed provided for the Falcon Gold project was used with a pre-amp at the feed. The signal quality and strength suggests that they both performed excellently. Compliments are in order for the builder of the feed.
3. The generator worked well. Once during the mission it did hick-up but only once and the cause is not known. The RPM dropped momentarily maybe 5% but then recovered immediately. I suspect that maybe some water is still present in the fuel system.
4. The 3 hp motor and variable frequency controller newly installed on the elevation drive performed like a dream with power required suggesting easy single phase performance. No new controls are installed and I suggest the building of a new control panel and interface to the old PC controller should be started asap.

   A rough review of slew rate performance indicates a base increase from 40 degrees per minute to about 50/55 degrees per minute with out applying any motor overspeed. LEOS (low earth orbiting satellites) are getting easier!

Critical review and comments:

1. AOS was difficult. Indirect QRM from several local stations really swamped us but a solution was present. Review of the video revealed telemetry on the audio subcarrier. If we had been listening for it we could have peaked up with the signal generator and nailed down the bearing and VFO tuning prior to launch. The telemetry was received prior to launch. I suspect that the video was there also, just in the mud.
2. APRS GPS bearings for aiming of the dish leaves something to be desired. The APRS package data was excellent and seemed quite accurate but the shuttle GPS was all over the map with errors around both 50 miles and 50 degrees.
3. On an exercise like this PC control may not be of much value unless the APRS GPS signals can be trusted. Just the same, I wish I had been able to record the dish activity for the duration of the flight. From this I could have derived/confirmed the maximum altitude among other trivial facts.
4. Experience with this exercise suggests that if all motors are converted to the VF drives (which we are now capable of doing) that 40 amps @ 208 VAC 3 phase will be more than adequate for operation of the site with both dishes slewing at the maximum rates.

   This compares to 96 amps minimum and 120 amps average to accomplish the same feat without the conversion. Note that peak current would be very significantly higher with the old drives.

   Although I did not have to employee it, I'm quite confident that the dish could have been stowed (in elevation) using the 115 vac power from my RV if the generator had failed.

   Comments? Reply to: slate@frii.com