Flight #4 "Nautilus"
Launch Date: Saturday, July 17, 1999
July 20, 1999
Calculations put the altitude of the highest photo taken at 85,945 feet
July 19, 1999
Success!!
Flight #4, renamed "Nautilus", was launched from a farm near Northwood
North Dakota at 9:50 AM Central Time on July 17, 1999. Conditions were
perfect, with very little wind and almost no cloud cover. The stack consisted
of a 1200g latex weather balloon, our normal parachute (recycled golf umbrella),
and our second gondola. For this flight, the gondola was modified
to carry a second 35mm camera. With one camera pointed down and the other
out the side, our ability to discern the payload motion and orientation
as during the flight was enhanced. The cameras were fired via servo
and synchronized within one second of each other. The vertical Pentax
PC-55 camera again functioned perfectly, taking all 35 exposures of its
Kodak 100 ASA color print film (one exposure was used to test the camera
after loading). The horizontal Minolta camera only took 31 of its
exposures (it too had one photo taken to test after film load, and an
additional image taken during servo calibration the night before the
flight). What caused the malfunction is not known at this time (likely
candidates are a frozen camera, a frozen servo, frozen camera batteries,
or possibly a microcontroller glitch). In any case, the
flight photos turned out very well.
Despite our plans, we didn't have enough time to assembly the proposed
payload stabilizers, or integrate any student experiments. The experimental
section held unexposed 800 ASA color print film rolls on this flight.
Some of our group has been debating various artifacts in flight photos
from past missions, and we decided to see if the effects of altitude were
causing any unforseen changes in the chemistry of our 35mm film. The
film canisters from the flight will all be loaded into the same camera
back on earth and used in a normal fashion (along with other rolls from
the same batch that stayed on earth and will serve as controls), and any
differences in image quality will be noted.
The flight went according to plan, lasting about two hours from launch
to loss of signal. Since our payload was over the 4 pound weight limit,
we had to file a NOTAM with the FAA and activate it. When the estimated
time arrived for the balloon ascending through 60,000 feet came, we
contacted the FAA once again. This turned out to be a painless process,
and will likely be a part of all future flights (unless we can design a
mission weighing less than 4 pounds again). The payload proved difficult
to track down, but was finally heard by a Crookston, MN ham who had
weak signal gear. The payload was recovered from a shelter belt near
a farm by Gently, MN at about 8:00 PM Central Time.
By group consensus, this was the last flight for which we would use our
"Payload #2". Our beloved pink styrofoam box, bashed, abused, mistaken
for a bomb, and now held together mostly by duct tape, is simply too small
and too beat up to adequatly serve for future missions. A new gondola
has been constructed out of white foam (which is lighter than the pink),
and will likely hold the guts of our next mission.
July 15, 1999
The new horizontal 35mm camera is mounted, tested, and installed on the
payload. The
new software has been written and debugged, and is installed
on the microcontroller. NOTAMs have been filed, and everything looks good
for the planned Saturday (July 17) launch at 9:00 a.m. central time.
June 15, 1999
Planning is underway for Flight #4 of the High Altitude Balloon Project. With
the successful launch and recovery of Flight #3,
confidance is now higher regarding our ability to track and recover balloon
payloads.
At the planning meeting on June 15, many new ideas for payload experiments and
subsystems were discussed. Some of the ideas that will likely be integrated into
the next flight are:
- A second 35mm film camera, pointed horizontally or on some sort of steerable mount.
- An electronic barometer to sense and report altitude.
- A better electronic thermometer (the current ones seem to be suffering instability).
- Swing dampers and stabilizers to keep the gondola from swinging/spinning during flight.
- Smaller dust collectors.
- Student payloads.
- Radiation detector.
We will try to incorporate damper designs made by other balloon groups to
stop the payloads swinging/spinning movements. Perforated discs on outriggers
seem the best approach. Adding fins to stabilize descent and a swivel to
the parachute lines should help keep the spin managable to minimize bluring
on the camera shots. Parts have been ordered to build a prototype active
stabilization system using a gyroscope designed for model helicopters and
either compressed air jets or fans, but it is unlikely that this system
will be ready in time for Flight #4.
The student payloads will be designed by kids at a local youth science center,
and will most likely involve exposing seeds or insects to the near-space
environment. Emphasis will be on small size and light weight. For the radiation
detector, if time allows a miniature Gieger counter will be interfaced to the
flight computer. If this proves problematic, strips of photographic film
sandwiched between sheets of flourescent plastic will be used.
We will be adding these items to our second gondola, which has now survived two
flights. The design seems sound and robust, and we are only utilizing about 1/4
of its volume for equipment at the current time.
It is almost a certainty that adding these items to the gondola will put us
over the weight limit the FAA puts on unanounced balloon flights. We will
therefore need to add a radar reflector, auxilary cut-down mechanism (and
associated radio receiver and/or computer control circuit), file NOTAMs
(NOtice To AirMen), and keep the FAA informed of our planned flight parameters
and progress. While this will complicate matters, the experience and tools
we have gathered in previous flights will make it easier to manage than if we
started with heavy payloads.
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