[amsat-bb] Re: ARISSat-1 Deployment Scrubbed

Stephen E. Belter seb at wintek.com
Wed Aug 3 09:20:58 PDT 2011

Tough decisions.

ARISSat-1 was taken to the ISS on a Progress vessel with 50-ohm terminations (dummy loads) installed on both antenna connectors.  At the ISS, the terminations were to be removed and the 2M (long transmit) antenna and 70 cm (short receive) antenna installed.  The ARISSat-1 tests used a coax cable to an ISS external antenna connected to the 2M connector on the top of the satellite.

The video of the spacewalk clearly showed the 2M antenna installed.  

>From a very brief head-on video shot, it appeared that the 70 cm antenna wasn't installed.  I don't remember the size of the terminator, so I can't say if the 70 cm terminator was present, or if the antenna had been installed but broken, or if the connector wasn't terminated.  My *guess* is that the terminator is still installed.

If launched as is, I think the downlink on 2M should work with the telemetry (BPSK-1000, CW, FM voice recordings, and SSTV).  What won't work is the U/v transponder.

Watching the video made it very clear how hard it is to handle the satellite "carefully".  So the risk (specifically mentioned by one of the cosmonauts) is that the solar panels won't survive taking the satellite back into the ISS to install the antenna and launch another day.  

One other potential scenario would be to remove the 70 cm terminator (if it is attached to the connector) and launching today.  There is a *slim* chance that high-powered ground stations might be able to be heard by the U/v transponder.

Tough decisions.

73, Steve N9IP
Steve Belter

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On Behalf Of B J
Sent: Wednesday, August 03, 2011 11:36 AM
To: amsat-bb at amsat.org
Subject: [amsat-bb] ARISSat-1 Deployment Scrubbed

Apparently, an antenna went missing so it's not known if ARISSat will be transmitting properly.  Deployment might occur later during this EVA pending a decision from mission control.


Bernhard VA6BMJ @ DO33FL

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