BEAR 1 & 2 Flight Capsule Construction

SM foam board was cut on a table saw
for the flight capsule.

 
Pieces were held together with masking tape while being dry fitted and then glued with epoxy resin.
Extremely light (0.6 ounce) fiberglass cloth was applied after lightly sanding the foam pieces.

The cloth is cut to size and positioned on box.
Epoxy resin, thinned with 99% isopropyl alcohol to cream consistency is applied, starting at the center and working towards the edges.

Thinning the resin makes it easier to apply and also reduces the amount which is applied and therefore the weight of the finished capsule as well.
A close-up of one of the corners showing how nicely the light cloth flows around a corner with out any creases.
To provide strain relief for the supporting cords, 3 pieces of nylon rod were cut and drilled out to accept the supporting cords diameter. External threads were then cut to help the epoxy adhere that was used to glue them into the holes drilled in the side panels of the foam box.

Here glass cloth is being applied to the exterior of the box.

Box is 12" in diameter, 8" high and constructed of 1" thick foam board.

Completed box weight was 219 grams (7.7 oz).
33.9 grams (1.2 oz) of this weight is the glass cloth and epoxy resin.

The covering adds strength, protects the foam from impact damage and the additional 15% weight is well worth it if the box is going to be used again. (the extra weight is actually <5% when the other capsule components, like the antennas and parachute, are considered.
Finished Flight Capsule
with APRS and
Cross-Band Repeater
Antennas

 

Prior to the BEAR-1 flight, the
payload capsule hung in the back yard for several days while operating the APRS tracker continuously on several different battery choices to determine how long each would last.

 

 

Below - Capsule with APRS tracker
and room for a cross-band repeater,
camera and other future equipment
The 2 antenna feed-lines for the APRS tracker & Cross-Band Repeater are laid in grooves that allow installing the lid and maintaining a good seal.

GPS antenna is placed within a styrofoam shelf just under the lid.
 

BEAR was aboard
and ready to go.
BEAR-1 package just before being launched.

 

 

 

    

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