Article

LPSU13 Dragahedron                                    June 11, 2009

This LPSU (ME406) team built a control box that could quickly (~1min.) attach rigidly to the balloon eliminating spin during flight. It worked. Observations from the 8th story of the parking structure downtown following the launch proved it out and we got it on film. Another notable innovation was a skewer mount used for the GPS which always kept it skyward no matter what the box orientation. But the ‘mission’ is named after a rigid, always deployed, tetrahedron tied to the payload dubbed a Dragahedron. It served as our parachute and worked perfectly—at least this time. We will make several of these for different payload masses and keep flying them too until disaster strikes. The final report for the project is attached below.

In general the launch went without a hitch. But it was a little less exciting in that we only received position updates every 15 minutes or more. As a result, we were somewhat relaxed, trusted the predictions phoned to us that morning by Donovan and just drove up to the thing hanging in a tree near the road in beautiful countryside 20miles nearly due west from PSU!

That doesn’t mean everything worked. Only one thing didn’t--and it bugs me bad…On the 'Images' page is a plot of the altitude data from the Wintec WBT-201 GPS. This device was to store the high resolution gps information for download after retrieval—it was not used for tracking. I was told it would log all GPS elevations. Others don’t. Well, it certainly has a hard cutoff at about 107,000ft, which was a total bummer for this flight because otherwise we may have broken our own altitude record on accident. The magnified view at right shows the apex history and some extrapolations. Assuming a 5 minute dwell (common) near the peak elevation prior to rupture, we would estimate about a 124,000ft elevation at rupture. We think for sure the balloon went over 120,000, but how much more? We’ll have to do it again and that’s ok with me.

The images are stunning. A few sweet images are attached: got the balloon and the moon and plenty of other beautiful scenes way above 100,000ft. Ben has used them to construct a 360º panorama of a typical NW cloudscape. I want to go where these balloons go. It is beautiful up there.

Here are the stats…

LPSU13…3000g latex balloon, Hydrogen filled, ~2.5lb free lift
Max alt. >120,000, <124,000ft (no official value)

Single Box: uniquely rigidly mounted to balloon containing OrbiTRAX SX1 low rate (1 per 15min) transmitting GPS on an internal self righting mount, high rate onboard non-transmitting GPS (WBT-201), 2 12.1Mpx hacked cameras vertically oriented and 180º from each other focused on horizon, heater/battery: 1922g.
No parachute, but a ‘Dragahedron’, coined by Jenna Faulkner. It’s a rigid, always deployed tetrahedron sized to work like a parachute but never suffer from deployment problems: 145g
Dog tracker: 110g
Total payload (incl. tape): 2.38kg (5.23lb)

Launch time: 5:57:02 PDT, 6/11/2009
Ave. rise rate: 913ft/min
Max. elevation recorded: not measured, est.> 120,000ft, < 124,000ft
Final descent rate: 2400ft/min (impact at about 27mph)
Max descent velocity: not measured
Landing time: 8:38:40 PDT
Total flight time: 161min
Ground distance: 20.2 miles West! A first.

People…
LPSU Team: Ben Semerjian, Max Gibson, Jenn Falkner, Michelle Hancock
LPSU: Launch: Yongkang Chen, Ben Semerjian, Donald Bell, Jenna Faulkner, Max Gibson, Michelle Hancock, MMW, and LPSU Alumn Donovan Finnestad (in command center)
LPSU: Recovery: Yongkang Chen, Ben Semerjian, Max Gibson, MMW, Jenna Faulkner, Donald Bell.