EdgeOfSpaceProgram

From JimWIKI

Jim's Edge of Space Program

Welcome to the Wiki!

I have a long term plan to fly a payload to the edge of space and photograph the curvature of the earth. While there have been many examples of how this has already been achieved by dedicated individuals or teams who just get out there and do this, I'm far happier thinking of this as a long road trip across an undiscovered country, stopping off at all sorts of interesting places along the way.

To get a payload up to the edge of space will likely require a helium weather balloon as the main vehicle, carrying the payload, which returns to earth under a parachute. This is a well documented approach with notable successes. However, the major drawback for me is with the payload return to earth system. Most of the documented missions of this type are flown from sparsely populated areas where a landing zone of 100 square miles is perfectly acceptable. As I will be flying from the UK, where there is little in the way of desert, I need to implement some kind of autonomous guidance capability to the payload return system. Safety and Control are the primary drivers of this mission (followed by budget!); I don't want to be causing a multi-car pileup on the M6, shutting down Heathrow airspace or crashing through someone's glass conservatory.

It follows then that the first major task has got to be designing and testing the payload return system.

The PRS will follow an iterative development process, starting with simple dead weight drops from a test rig at low altitude to fully autonomous GPS guided descents from the highest altitude that can be practically achieved.

To create a platform for PRS testing, I am turning to another well documented and researched field, Kite Aerial Photography (KAP). This will be the first stop on my road trip to the edge of space!

The P.R.S. (Payload Return System) Plan

The PRS test platform will be developed using skills gained from learning about and participating in KAP. The steps involved will roughly be:

• Create PRS test platform
  • Develop and fly a KAP Rig
    • Determine and Purchase a suitable Kite able to carry a useful weight of payload in common wind conditions -done
    • Learn to fly the kite, develop good practices and safety, with no payload attached -done
    • fly with a dummy payload, such as a bottle of water to understand how this changes kite dynamics -done
    • fly with a camera, using a local CHDK script or intervolometer to take a sequence of images or shoot video -done
    • Create a Pan and Tilt Rig with Shutter control that will allow control from a ground station using 2.4Ghz Radio -in progress
  • Use the KAP rig to create the PRS drop test platform
    • Develop quick release mechanism, that will release a cable through servo actuation.
    • Drop a dead weight from the PRS test platform on command from the ground station via 2.4Ghz radio link
    • Confirm that the quick release mechanism will operate according to design in a variety of conditions.
    • Drop a dummy payload under a Ram-Air, Airfoil or similar Canopy
    • Understand the characteristics of the canopy, determine glide slope.
    • Move the radio and control systems of the rig to the payload, effectively detaching the rig from the line on command from the ground station
    • conduct drop tests with the camera attached to the rig shooting video of the quick release mechanism activating
  • Built steering control into the Payload
    • Add servo actuation of the braking flaps on the canopy to enable steering and braking.
    • add capability to the ground station to control in real time the actuation of the steering servos
    • Successfully guide the payload to a predetermined landing spot via manual steering control from the ground station
    • Iteratively increase altitude of the Rig to create longer payload flights.
  • Build Autonomous control into the payload
    • Add GPS to the Payload. Perhaps add barometric air pressure sensor to improve altitude determination
    • Build telemetry downlink to the base station.
    • conduct flight tests under manual control at modest altitudes to monitor telemetry
    • Begin to adapt 3rd party autopilot / UAV solutions to work with PRS input and output design. (candidates include ArduPilot and BlimpDuino)
    • Fly tests under manual control with autopilot in shadow mode
    • Fly tests with autopilot in control with incrementally increasing altitudes

Success Conditions

I'll consider success of this goal to be the controlled release of a payload (camera in video mode) at a significant altitude from a kite, in good weather conditions. It is then to be followed by an autonomously controlled descent under canopy and landing to within 100m of a predefined marker. This should be repeated no less than 5 times in a row without any significant failure of any component of the system or landing outside of the designated area.

Jim 18:06, 22 January 2009 (GMT)