Blue Skies: Project History

Joachim Köppen DF3GJ Kiel/Strasbourg/Illkirch June 2004

• January 2004: SSP director Juan de Dalmau shows me images of the Zuni sounding rocket and suggests to think about science projects suitable for MSS and SSP students
• January 2004: after excluding what kind of science cannot be done at a maximum altitude of 8 km and imagining what can be done, the rough aim for the project is outlined, and submitted. Major questions to be solved are the choice of the photodetectors and the colour filters, as well as whether simple devices could measure colours with sufficient reliability
• February 2004: review of the proposed ideas. Blue Skies is found interesting enough for realization
• March 2004: construction of simple photometer with a LDR. Tests show that LDR is more suitable than photodiodes and -transistors which are too sensitive in the infrared. Measurements with the LDR photometer demonstrate that the colours of the sky at various meteorological conditions can easily and reliably be distinguished. The various hues of the blue clear sky seen at various elevations can be distinguished. A number of colour filters are tested, and it is found that good red and blue filters, along with a white comparison measurement provide a practical means for measuring the colours. UV and IR measurements are found not to be of sufficient importance to justify the additional expense.
• late March 2004: teleconference with other members of the sounding rocket experiments; visit by Cristian Serdean (Univ.Kent): showing that an eight-bit PIC would be ideal for providing the interface between the analog output of the photosensors and the digital storage of the data. Procurement of the LDRs and material for the filters.
• May-July 2004: Internships of Erling Håland and Oliver Teynor at the University of Adelaide. Construction of a test version of the sensors. Design and construction of the mechanical and electronics hardware for the flight version of the payload. Delays are caused by the manufacturer's late shipment of the PIC development board.
• July 2004: Erling Håland and Mark Ciotola (SSP student) develop the software for the PIC.
• July 2004: Integration of the payload by SSP students. Due to lack of time, only a functional test can be executed, but not a proper calibration of the sensors.
• 3 August 2004 at 10:55 local time: launch of the sounding rocket Z66 (ISU designation: Zuni 1) at Woomera. There is a low layer of grey clouds, and there are blue skies above, as seen on the onboard TV camera. After a flight of 5 min 4 sec, the payload is retrieved in excellent shape, but unfortunately no data was stored. Apparently, the software had been finished only in the night before the launch, and thus had no chance undergoing any rigorous testing ...