Date: August 8, 2003
Launch Time: 09:14 AM PST
Objective: Test launch of ballooning system and methods.
NBS-03-02 Telemetry Data File (MS Excel)
Balloon Weight: 300g
Max Altitude: 34,488' (Above Sea Level)
Ascent Rate: 1090 ft/min (average)
Descent Rate (at landing): ~700 ft/sec (average)
Mission Range: 30.5 miles (linear distance)
Mission Duration: 56 minutes (liftoff to touchdown)
Conditions: Clear, ~80 F, very light NNE breeze on surface.
Summary: Our second mission attempt was successful on the whole. We decided to delay our departure from Reno until after the 5:00 AM weather data was obtained (online) because we noticed some large changes in predictions from day to day (so using the previous day's weather was risky). This got us to the launch site at around 7:45 AM. We decided to launch from very near Gerlach due to winds and ease of access to good roads. We aimed for a <30,000' maximum altitude because of wind speeds aloft getting high. This led us to use a 28 minute cutdown timer in order to keep it on the playa.
We had two APRS radios on board. Our "standard" Kenwood TH-D7A, and an Alinco DJ-C4 with a TinyTrak module. Both functioned perfectly for the first 16 minutes. At that point, the Alinco stopped sending packets. We suspect that the batteries ran out. We added this redundant payload at the last minute, and it had not been tested for battery life. It was not likely the Alinco or its batteries. We are not sure if there was difficulty with the TinyTrak or the GPS though (or their batteries). The telemetry details are "suspicious" and suggest a possible loss of GPS power.
The electronic camera did not have any pictures upon recovery. We are not sure why, because the relay/timer was firing periodically pre-launch and the batteries were not drained.
The payload descended more rapidly than our estimations predicted. We expected about 550 ft/min at touchdown, but saw closer to 700 ft/min. This may be due to the cut-out in our parachute that wasn't accounted for in the parachute performance software (LiftWin).
Overall, our primary objective was to receive telemetry during the entire mission, and recover the payload using the timed cutdown system. These objectives were accomplished without problem.
Panoramic view of the landing site. This one was pretty easy to find. We were able to drive to within about 1/2 mile and hiked from there. The last telemetry packet was pretty much right where we found it. Thankfully, it landed short of the "hill" (1200') in the background that was about 1/2 mile away. Had it landed on or overshot this hill, we may have lost telemetry before landing and needed to do some more serious hiking/climbing.
Mission Map. We launched from the lower left, near Gerlach. Landing was in the general middle of the Playa, but there is also a mountain there. The chase was not hard, and we probably just missed a visual observation of the landing. The last 1/2 mile of the recovery was very rough off-roading as the playa turned to desert dunes (etc.).
Readying for balloon fill. Top section of payload line is shown on the left, attached to lanyard ring and parachute. Cutdown burner is shown threaded in place for filling.
Readying the main payload bus module. We had difficulties with two of our 3 Kenwood TH-D7A radios. They weren't beaconing APRS data periodically. Fortunately, the third was working fine, saving us having to reset and re-program the radios at the launch site.
Filling is underway. Winds were very light, even at 9 AM. Immediately after this image was taken, the chase team hit the road to get downwind before launch.
After the chase, we found the payload in fairly good shape. The aluminum tubes running the cord were in the worst shape. Lots of bent tubes.
The payload chain upon recovery, before we messed with it.
The cutdown control box and the lanyard ring.
The cutdown control box, before final closure. We did
a few short tests before launch to confirm relays were firing, and then
we set the timer DIP switch settings accordingly before closing it up.
The cutdown system control board. Main functionality
is provided by a BASIC Stamp BS-2p. The delay is set mechanically through
the 8 switches (blue DIP) on the right, giving us 256 different settings
without having to re-program on-sight. The two relays (5Amp) are at the
top left (one is a backup). The lines running to the left go to the burn
battery & burn coils. During firing, approximately 2.2 amps flows
through coils with our chosen batteries (Lithium).
The burner unit consisting of two burn coils (inside)
and a protective case. The case prevents the coils from accidentally melting
or burning anything outside of the container (like the parachute).