Step 5: Parachute
Once again, I like Amazon.com. Our friends over at Project Aether have designed a parachute that is just right for our needs. 
After many experimental trials with high altitude weather balloon payloads, we have arrived at this optimized parachute design. It allows for a stable parachute deployment at ~Mach 1 when the balloon initially bursts in the vacuum of near-space. The 36in diameter parachute is designed to yield a descent rate of 1500ft/min (15mph) once back into the thicker atmosphere near sea level.
The bright orange and white gives a high contrast for high visibility during flight and recovery phases. The Project Aether recovery chute is individually hand made in the USA with a 6 sided design using 1.9oz/sqyd (70 Denier) ripstop nylon. The silicone coated parachute makes the parachute waterproof on both sides and is lighter than standard polyurethane coated chutes.
The waterproofing ensures that the chute opens even if soaked in water or rain. All seams are sewn with nylon bonded thread using a durable 5-thread safety lock stitch, overcasting and finished with a clean seam. The shroud lines consist of MIL-C-5040 Type 1A military survival cord at a mere 1/16" in diameter yet has a tensile strength of 100lbs per line. Three reinforced xxx lines, using MIL-C-5040 Type 2A military survival cord, complete the chute at the top for easy in-line connection to weather balloon assemblies or rocket nose cone trains.