BallastHalo

To test the ballast system espcially the X-valves that we are using on the Atlantic Halo missions.

The mission will use a latex balloon with a small vent in the neck, over time the amount of helium will decrease therefore reducing the lift, this will causes the ascent rate to decrease.

Using the ballast system it should be possible to drop ballast to compensate for the loss of helium causing the balloon and its payload to float.

After a period of time the ballast system will drop the remainder of its ballast which will result in more free lift and the balloon will continue to rise to burst.

Aim is to test the feasibility of putting a vent in a latex balloon

Will use a simple flight computer (arduino, gps, radio, cutdown) and a vent will be constructed that will be placed in the neck of the balloon once it has been inflated. The vent will have a small hole which will allow helium to slowly escape until the ascent rate decreases sufficiently to result in neutral bouyancy and the balloon floating.

Will need to cutdown from the balloon to avoid the balloon descending slowly and causing trouble on landing. On cutdown the balloon will then rise again and burst while the payload descends

Need to descend on a particular flight profile (such as time of day for launch etc)

Flickr Stream

Payload Box complete

Cutdown finished and tested.

Launch - 17/07/09, Churchill

AVRmetrix - custom PCB with Atmega168, Radiometrix NTX2 and 3.3v Power supply

Ublox RCJ-LJ GPS module (TIM-LF Chipset)

Cutdown board - Power supply, relay, nichrome wire

Balloon - 1500g, vent - based on WB8ELK earlier experiements 1/16th” hole

Parachute

Read GPS using tinyGPS library and parse the data

Send data over radio using rjharrison's RTTY Code

Every minute calculate ascent rate

Cutdown logic:

17/07/09

Launched

Ascended at 5m/s,

Didn't achieve float

Burst at ~35000m

Landed near Haverhill - retrieved at night

Telem Log

KML file

Note - lost telemetry during flight - went to eat hence large gap, most likely scenario is that it continued to ascend up rather then float.

int altitude overflowed → needs to be fixed

Need a slower ascent rate to achieve float (2-3m/s)

Don't drop the payload out of the window

18/07/09 - 19/07/09, 10hrs 50min flight

Launch pictures - simonvc Flickr

Launch videos - simonvc youtube

Flight was launched from Churchill at pretty much exactly 18:00GMT and ascended at a rate of 2-3m/s

Float was achieved at ~21.15 GMT at an altitude of 27450m which was maintained for 7hrs 15mins (with a decrease of 500m)

GPS lost lock at 22:45GMT (possibly due to being too cold) and restarted at 04:09GMT (warming by the sun)

Balloon burst 04:12GMT and descended by parachute landing 53.085,-2.176 and was found by Laurence up a tree

At present planning a rescue

Telem Log Part1

Telem Log Part2

KML file

Code

Really need temperature sensor onboard

http://www.sensor-networks.org/index.php?page=0827727742