[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

RE: OSCAR-E question

> As far as heat goes, this is basically the same physical layout as the
> microsats. If they had heat problems then there may be an
> issue but I am not aware of any problems.

The various Microsats (-16 thru -19, -26, -27 and -31) ran at temperatures
ranging from ~-2 deg C to ~+10 deg C thanks in large measure to the
excellent thermal design achieved by Dick Jansson, WD4FAB. Nearly all the
exposed surfaces are either solar cells or OSR (Optical Solar Reflective)
tape. OSR is a really shiny mirror-like metallized kapton tape.

If a satellite is too cold (like below about -10C), then the NiCd batteries
"freeze up", producing losing their good electrical properties. Temperatures
above ~+30C "cook" the batteries making them lose useable lifetime.

Steve is right that "Echo" is VERY similar to the original Microsats. The
size is slightly and fabrication techniques have experienced Darwinian
evolution. Solar panel (remember that the panels are a large part of the
exterior as seen by the sun) technology (new cells are more efficient and
they are fabricated in different sizes) has evolved so that the appearance
is a tad bit different. (But as the photos in Rick's article show, the
12-year  difference between the satellites is less than the difference
between a 1998 and 2002 Toyota!)

73 de Tom, W3IWI

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org