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Flight #4 - 2002b

Flight Parameters
Launch Date/Time Thursday, 2 May, 2002 at 9:00am
Alternative Date 6 or 7 May 2002
Launch Site Wiley School (38º 04.6'N, 97º 56.9'W) in Hutchinson, KS
Primary Transmitter / Antenna VX-1R HT running APRS on 144.39MHz / Vertically polarized dipole
Backup Transmitter / Antenna PC Electronics 1.5W ATV Transmitter on 434.00MHz / Horizontally polarized Little Wheel antenna.
Backup Transmitter / Antenna Keyed oscillator on 147.55MHz (no modulation) / Horizontally polarized dipole
Balloon / Gas Kaymont 1200gram / 240 cu feet of Helium
Estimated Burst Altitude 93,000' MSL
Estimated Ascent Rate 1300' per minute
Estimated Descent Rate Approx. 1400' per minute at touchdown
Capsule(s) weight 5lb 11oz (2577g) including parachute, rigging, batteries, etc...
Chase Frequencies 147.12+, 146.82-, 146.52MHz, 7.2535MHz


Flight Results

The school launch was basically a text-book launch and recovery. Most systems worked flawlessly, but we did have a few surprises. The kids loved the event and I think we left a very good impression on them.

Flight Statistics
Launch Date/Time Thursday, 2 May, 2002 at 9:41am
Launch Site Wiley School (38º 04.29'N, 97º 54.65'W) in Hutchinson, KS
Burst Altitude 104,150ft (31,745m) MSL
Average Ascent Rate 1196ft/min (6.08m/s)
Measured Descent Rate Approx. 870ft/min (4.42m/s) at touchdown
Touchdown Site 7 miles northeast of Emporia, KS (38º 29.3877'N, 96º 06.6215'W)
Touchdown Time Thursday, 2 May, 2002 at 11:43pm
Recovery Time Thursday, 2 May, 2002 at 12:03pm
Distance Traveled 102 miles as the crow flies
Total Flight Time 2 hours 02 minutes
Downloads Lat/Lon File, Flight Analysis



Lessons Learned

  • Having dedicated APRS tracking stations ready to go helped the pre-launch stress. Zack's FT-2700 and TNC are mounted inside of a tool box with antenna, power, and data connections on the side. APRS setup took about two minutes instead of 10-20 minutes when I was robbing parts from other systems around the house. I think it's also far more reliable since I don't have a bunch of exposed connections.
  • The Little Wheel antenna seemed to perform fairly well, but we still aren't seeing the distance we were hoping for. I think an investment in a large antenna and a good pre-amp is the next step.
  • I had been over-estimating our descent rate. This was the first flight where we good data logs just before touchdown. In the past, we had estimated about 1400ft/min but it appears from the initial analysis, that we are actually slowing to under 900ft/min.
  • The APS camera exposed almost all frames of film while still sitting on the ground. This was the same problem we saw on PT2002a. The problem is related to RFI and we thought we had improved the situation, but apparently not. The next step is shield cables and possibly an opto-isolator on the shutter button.
  • We again increased the number of packets sent per minute which helped our overall tracking ability. We now transmit GPGGA, GPRMC, wait 30 seconds, GPGGA, GPRMC, telemetry packet, wait another 30 seconds. This configuration produces a lot of traffic, but gives us reliable positioning information every 30 seconds.
  • The 50lb-test Kevlar SpiderLine 'weak link' was again broken upon recovery. Since we had not had a valid sucessful test (i.e. 2002a), we flew with a slightly longer 50lb-test monofilament backup. The monofilament was not broken, but the Kevlar line broke right at the knot where it was epoxied.