I know an Astronaut

[Dave VK6KV]

Hi All,

Sorry (not really) for the cross post, and the chance to brag... But I know the NASA Astronaut currently flying his way towards the ISS on Soyuz MS-28. As does Randall VK6WR

(Dr) Chris Williams did a lot of boots-on-the-ground work with Randall and myself, and others, in building and developing the early Murchison Widefield Array radio telescope, a project which has kept me employed since March 2009 and allowed me the financial freedom to play Amateur Radio.

Go gett'em Chris!!

For those keen to watch, Soyuz MS-28 will dock with ISS in a little over an hour,... this link should work...

https://www.youtube.com/watch?v=71ffidjfuo0

And if you want to watch the (now historical) launch sequence here's another link - https://www.youtube.com/watch?v=gWhAbWnm_oM

Cheers, Dave VK6KV

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[Denis Brown]

Thanks for the heads up, Dave.

Best wishes to all for a successful mission!   What was Chris' role in the Murchison, by the way?

73

Denis

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[Dave Emrich]

Hi Denis, all

Chris helped develop and debug early code blocks to process data from before the "full" telescope was even built - while we were operating a 32-tile (*) prototype. He also built some on-the-fly code, at the telescope site, to determine the direction of an interfering signal late one afternoon, which was pinpointed to an experimental DTV transmitting tower built at Morawa... It was a privilege watching Chris think, code, design, consider, and solve some complex problems we had. Back at MIT in Boston Chris was a vital member of a team building the telescope control and data processing software and systems.

(*) A Tile is a group of 16 dual-polarisation (crossed) dipoles arranged in a 4 x 4 array on 25m^2 of builder's mesh. The signals from the 16 North-South dipoles are electronically delayed (switched through variable length delay lines) before being summed to form a "North South" beam pattern. Likewise, the signals from the East-West dipoles are delayed/summed to form an East-West beam. By electronically switching the delay steps, the beams can be steered around the sky.

The pre-prototype that Chris "cut his teeth on" consisted of 32 such tiles with very much manually operated control systems, covering a roughly circular area about 600m in diameter. The initial full telescope consisted of 128 (new) tiles arranged over an ellipse about 6km east/west and 4km north/south, and over time 128 more tiles were added bringing the east-west footprint out to over 9km east/west and 7km or so north-south.

Cheers, Dave Emrich

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