HD Video From the Edge of Space, On the Cheap

SoundDoc75 links to a page describing the motivations and problem-solving behind "a 10-minute HD video taken on August 24th with a Canon Vixia HF20 HD camera suspended from a 1500g hydrogen balloon and launched near Edmonton, Alberta. This is the first known amateur video taken from this height — 107,145 feet."

Comments

Re:"Edge of Space" is 100 km

[jguthrie]

100Km is about 328,000 feet. That's why Space Ship One had a tail number of N328KF.

Also, the North Texas Balloon Team and the South Texas Balloon Project routinely (with launches approximately annually) send balloons with video cameras to altitudes in excess of 100,000 feet. Those are just the two balloon projects I'm familiar with. I am sure there are others because it's not particularly hard to do.

So, this is pure ho-hum to me. Let me know when they've done it a couple of dozen times.

Re:Valve

[TheHawke]

Weight restrictions vs performance. The envelope is filled to 25% capacity with helium, then released. As the balloon ascends, the gas expands, filling the envelope completely. Once it reaches altitude, it will stay there until either the membrane fails or programmed cutter severs the the tether, letting the payload descend back to the ground. A release valve would prolong the flight, but with amateur rides like this, they usually let it ride up until it bursts at a calculated altitude from the overpressure. 100K feet is impressive and the video is stunning.

Re:First amateurs? Not quite!

[the 99th penguin]

The Apollo astronauts were trained by a professional photographer on how to use the custom (Hasselbak or something close to that.) cameras for use on the moon.

They were modified Hasselblad cameras (a very nice medium format film camera). They brought the film back but left the cameras on the moon.

Re:legal? safe? ATC?

[fatboy]

I am a member of the Tennessee Balloon Group. We had a parachute failure on one of our flights. TABEL-5 if I remember correctly. It burned in at a whopping 55 MPH and landed in a tree. We only launch if the predicted burst and landing is over a rural area.

Re:"Edge of Space" is 100 km

[bcrowell]

The boundary of space is conventionally defined at 100 km, or about 260,000 feet. Sending a weather balloon to 107,000 feet is nice, but it's only 40% of the way to the "edge of space." Which, of course, you could have realized just by thinking about it. We define "space" as meaning "above the sensible atmosphere," and if you get there in a balloon, it couldn't be above the atmosphere.

It's an exponential decay. There is no sharp cutoff. Nothing special happens at 100 km. The scale height of the earth's atmosphere is about 7 km, so the pressure at 107,000 ft (32 km) is about 10^-2 of what it is at the surface, while the pressure at 100 km is about 10^-6 of surface pressure. It's not like somewhere in between 10^-2 atm and 10^-6 atm there's a mystical barrier that suddenly makes balloon flight impossible. It just gets harder and harder; to stay aloft with a given volume of hydrogen, a balloon at 100 km would have to have 10^-4 of the weight of a balloon that's neutrally buoyant at 32 km. It just happens to be difficult to make a balloon with sufficiently thin walls, high strength, and low surface-to-volume ratio.

If you watch the (very cool) video, the sky is black, there is no sound, and the curvature of the earth is extremely obvious. I would call that the "edge of space" -- for some definitions of "edge of space." There's not some international standards body that defines terms like "edge of space."