Some time ago, I gave a little advice to someone involved in the MESSENGER - MErcury Surface, Space ENvironment, GEochemistry, and Ranging satellite project. Not exactly a huge contribution, but it helped them out of a tricky situation with the on-board computer. It was enough so I was sent an official T-shirt, the equivalent of a mission patch as being part of the team. Which was rather kind of them, considering my miniscule contribution.
Here's a view from MESSENGER now
From Space Daily :
A day after its successful flyby of Mercury, the Messenger spacecraft turned toward Earth on Tuesday and began downloading the 500 megabytes of data that had been stored on the solid-state recorder during the encounter.We only had 200 or so Megabytes of storage on FedSat, but as we were out of ground contact for all but 15-20 mins a day, the principles were the same.
All of those data, including 1,213 images from the Mercury Dual Imaging System (MDIS) cameras, have now been received by the Science Operations Center at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
Preliminary analysis of these data by the Messenger Science Team has confirmed that all seven Messenger instruments are healthy and operated as planned during the flyby.
So I am claiming about one t-shirt's worth of the credit for that.