This is probably old news to you ARISS guys`, but I thought I would report on a little experiment I tried yesterday: putting my TH-D72 on 145.825 during an ISS pass.
Yesterday morning included a pass with max elevation of 56 degrees, so I screwed in the rubber duck, set the radio for APRS, and waited. As expected, I had no trouble hearing ISS. Six stations relayed by the ISS digi showed up on my list. However, also as expected but a little disappointing, ISS didn't hear me. Several high power fixed stations drowned out any QRP stations who might have been there. They appeared to be operating automatically, I won't mention any calls here, but if you're one of them, you know who you are. My grid square is DM41..
73 Ray W2RS