The Venture Crew consisting of
high school students in Huntsville, Alabama are flying an experiment on the
Deep Space Test Bed balloon engineering test flight*. The experiment contains a very low frequency
(VLF) radio receiver and a video camera.
The VLF receiver is donated from the INSPIRE Project and
The Venture Crew’s experiment includes
simultaneous measurement on the ground with a newer donated INSPIRE
receiver and by other volunteer VLF enthusiasts around the
* The first science flight of the DSTB Facility will carry successfully proposed and peer-reviewed science team experiments to high altitude overAntarcticaeither later this year or next.
The DSTB gondola package was “hang tested” after
mating with its solar array skirt at the NSBF inFort
Nearly all of the experiments have been tested in preparation for the compatibility test. That includes the Venture Crew VLF/camera package. There are three possible antenna configurations I am currently considering. The first to be tested is to hang the antenna directly below the gondola. I will use the compatibility test to determine whether the flight telemetry system overloads the input to the VLF receiver. If it does, then during the compatibility test I will move the antenna to the end of one of the booms that are part of the gondola. That will move the antenna some 20 feet away from the gondola and the telemetry antenna. If neither of these configurations work, then I will be forced to use a short antenna (much less than the 50 feet currently planned) that hangs downward from the experiment package but not long enough to extend into the antenna pattern of the telemetry antenna.
The UC Berkeley gondola did not fly this morning; the winds were too strong. Consequently an attempt was made to perform the compatibility test for DSTB. The winds were too high for that to be done as well. The decision not to perform the full compatibility test was made after the main body of DSTP was brought outside the building. Some parts of the test were performed, but without the solar array skirt and without full operation of the instruments. The main gondola was fitted to the ballast weights and balanced. The gondola was raised as high as the launch vehicle could lift it in order to plan for the later full compatibility test. An isolation transformer was added to the Venture Crew video camera output. There was a problem with ground of the SIP to the gondola, but I believe the Venture Crew package was determined not to be the cause. Once this test is passed, no major changes are allowed on the package and planning starts for selecting a flight date.
Again the winds were too strong for UCB to fly and to perform the compatibility test. Since the local support crew has been up early for several days in a row, the decision was made to postpone the next attempt at a compatibility test until Tuesday, May 24.
The compatibility test took place this afternoon. The test was successful. Photographs have been added to the photo album from the test. Three recordings of the VLF are also included. These are wave files. During the first recording the gondola with solar array skirt was close to the ground and the SIP/CIP RF antenna were coiled up on the gondola and pointing in random directions. During the second wave file the gondola was raised and the RF antenna were deployed downward to a location just below the bottom of the solar array skirt. The VLF antenna remained deployed only down to just above the bottom of the solar array skirt. In the third test the VLF antenna was lowered to the ground with no other changes. During the first test I was able to determine that there was considerable noise in the downlink even after the VLF receiver was turned off. The noise appears to be coming from the CIP computer. The VLF receiver was turned off before the end of each recording.
I can see more interference in the last of three tests than in the second when the antenna was held above the RF antenna radiation patterns. That would lead to a VLF antenna length of perhaps 11 feet if that were the length flown. I am prepared to fly up to 15 meters of VLF antenna. The current situation is that I have suggested I want to deploy this longer length. I am reconsidering that request due to the enhanced noise at low frequencies with the antenna deployed into the RF antenna pattern. My initial reason to deploy to 15 meters is because all the local sources of interference are short wavelength and the desired signal wavelength is quite long comparatively. The longer VLF antenna might not pick up more local noise, but will pick up more natural noise with the longer length.
I have been told that we aren’t likely to launch for two weeks. We may hear more about that tomorrow. My plans for tomorrow are to replace the 9V lithium batteries in the Venture package and do the final wrap with light blocking film and white duct tape. I need to decide whether to stick with the current antenna deployment decision as well.
Today I will close out the Venture experiment package by
replacing the 9VDC lithium batteries with two that will fly with DSTB. That was done this morning. I have also cut out a foil wrap I will
install this afternoon with tape to protect the package from the Sun’s
heat. Later today and tomorrow we will
finish out the UAH eMass experiment package.
We are waiting on a couple of parts for that. By tomorrow I hope both are completely ready
for flight. We still expect UC Berkeley
to try to launch Saturday and our earliest opportunity to fly would be around
the middle of next week. I have added
images from the Venture Crew in
We closed out the UAH eMass experiment today. All the student experiments on DSTB are now
integrated and working. That is a big
relief. At the weather briefing they
reported a 40% change of showers tomorrow and not much better for
Saturday. Of course it therefore follows
that they will come out and pick up the UC Berkeley gondola with the launch
vehicle at in anticipation of
a possible launch tomorrow. That’s
what they are planning anyway. The
weather forecast starts to actually look good on Sunday and Monday. Maybe they can get it aloft at the start of
the new week. I gather that DSTB can be
anticipated to be on-deck to find good weather for launch about one week after
UC Berkeley launches. I also heard today
that they have extended the launch season at
As all reasonable people expected,
Some photographs from Michael Midekey’s
practice session yesterday at
As best I can tell,
As you all probably know by now, the UC Berkeley launched yesterday in the last morning. The next balloon package is FIRST. The first possible attempt for the next payload is Saturday. This will be re-evaluated and discussed at tomorrow's weather briefing. From the discussion today, Sunday actually look like a better chance of actually flying. If the next balloon happens to go on Saturday the first possible day DSTB would fly is Monday, but this is very, very optimistic.
Should any of the other participating individuals or groups wish to have information about themselves, their recording sites, or anything loaded into the photo gallery, please contact me at dennis.l.Gallagher@nasa.gov. I would be happy to put pictures and/or other information onto these web pages.
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