[HSIS] Launch Review

[Ethan Chew]

Hey All,

    Good analysis.  From what I found out about tracking;

   - When the GPS device says it is at a specific location, due to position
   update delays, that could mean the position 15 minutes ago.  So it is
   essential that you must not head towards the last position update, but wait
   for the payload position to become fixed before attempting recovery.  It
   would also benefit us to have a GPS on the tracker and a GPS on the balloon
   so their positions are known to base station people.  Altitude, speed and
   heading reporting is also helpful for determining the target's positions and
   what is happening to them.
   - Along with cell phones, ham radios will help with communication.
   - GPS is not 100% accurate.  A reported position could mean the payload
   is within 100 feet of defined position.  Also, the more cliffs/obstructions
   you have around you, there will be less GPS satellites recieved and GPS
   accuracy drops.
   - Recovery is not always ideal.  The payload can land in rough terrain
   and require you to do tree-climbing, rock/mountain climbing and/or hiking.
   Be sure to wear/prepare gear for such an expedition.  The trackers typically
   brought with them rope and ladders to reach such hard places.
   - Bring a driver's GPS (TomTom, etc.), a hand-held GPS and some kind of
   close-range tracking.  They will comnplement each other for different phases
   of the search (driving there, homing in and looking around the brush).  You
   can use these to home in to the position of the payload's reported GPS if
   you are using GPS tracking.
   - Not all roads to the payload show up on the GPS and offroading is
   sometimes a must.  Use off-road capable vehicles and bring a detailed map of
   the region of terrain and roads so you can find a path.
   - The locals are really quite friendly and familiar with balloon
   tracking, but be sure to respect private property lines and ask permission
   before entering.  Also, beware farm animals/dogs/bulls.  You do not want to
   enter their territory during a search.
   - Bill Brown may allow us to piggy back again.  We'll have to organize it
   with him.

Otherwise, our payload mostly stayed on and functional.  When I picked it
up, the phone was still on, but the camera had shut off.  (Batteries were
okay and full for both).  The software is the issue as the tracking
application on the phone shut down in-flight and the camera script stopped
working due to an inadvertent button trigger.

                 - Ethan

P.S. Good job guys.  We may not have gotten everything, but we did learn a
lot of valuable stuff about balloon flight.  Let's speak more at the
meeting.

On Sat, Apr 10, 2010 at 5:34 PM, Satyam Nayak <nayaksatyam at gmail.com> wrote:

> Positives: Nothing lost.
>
> Negatives: Nothing worked.
>
> Camera:
> Somehow stopped taking pics while still being packed. Need to determine if
> this was because of unintended button pushing or if it was because of too
> much flipping and turning while packing.
> The way it works with CHDK is that the shutter button starts and stops the
> script.
>
> For human convenience, the shutter buttons have a slightly higher profile,
> making them easy to click - and it is entirely possible that a zip tie dug
> into it once, and that caused it to pause the script.
>
> We need to find a way to package the camera such that none of the elements
> are pressing into any buttons.
>
> An ideal solution would be a foam enclosure of just the right size that we
> seal up after setting off the camera. I wonder if there is a way of doing
> this.
>
>
> Tracking / Cell phone:
> Stopped working even as we were packaging, but even if it had worked
> initially, we have no idea how it will hold up later on. I think everyone is
> in the favor of ditching the camera and going with radio chirpers. We need
> to investigate into this.
>
> Another thing is we need to make sure that the tracker keeps going for
> several hours, in case something goes wrong and our payload gets towed to
> another place. Even if it chirps once every 30 mins after the first few
> hours, we will at least have a general idea of where it is going.
>
> I am not exactly sure what the story for today was, I think Ethan can fill
> us in on the details.
>
> Packaging:
> The foam board backing is not a bad idea, but I think we need to pair it
> with something more structural for a standalone launch. We can even string
> them up separately like the way they did to the payloads today, that way we
> can use the best packaging for each module without compromising the other
> ones.
>
> It would also be nice to work out a design such that we can pre-assemble
> parts and put them together with relative ease once we put in the main
> components - since there really is no way around having to activate
> components just before the launch. I guess we should aim for a build time
> less than what it takes to inflate the balloon, so we can start as the
> balloon is being inflated, and have everything ready to go as by the time
> the balloon is ready.
>
> Component coupling:
> After today's experience I'd say that we want any component to rely as
> little as possible on any other component, to avoid catastrophic failures.
> We were not planning on any nonessential coupling any way, but I figured it
> was worth repeating.
>
>
> Overall, I think it was a good learning experience. It would have been
> nicer if at least the camera had worked, but this is at least much better
> than losing the payload without knowing that the camera had stopped working
> too. So all in all, given that both of our components failed, this is
> possibly the best outcome we could have had. We'll at least know much better
> when we send out our own standalone payload. Saved us a fair amount of money
> too.
>
> I am sure I am forgetting something, feel free to add your thoughts.
>
> Also Ethan probably has some observations from the tracking experience as
> well.
>
> -Satyam
>
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