Huge fan of portableapps for too much years to count.
I find Previsat is not available as portableapps. Althought it is a cool soft, available on sourceforge, then I assume open source and maybe a good candidate for portableapps.com
PreviSat is a satellite tracking software for observing purposes. Very easy to use, it shows positions of artificial satellites in real-time or manual mode. PreviSat is able to make predictions of their passes, predictions of Iridium flares and several other calculations."