Unfortunately, he only did one plaque.
"I subscribe to a Muggle bulletin which keeps me informed of progress on space travel. I didn't hear about Pioneer 10 until they reported its launch. But when I discovered that Pioneer 11 would also be leaving the Solar System forever," Professor Quirrell said, his grin the widest that Harry had yet seen from him, "I snuck into NASA, I did, and I cast a lovely little spell on that lovely golden plaque which will make it last a lot longer than it otherwise would."
Unless he lied.
Update: This post has also been superseded - new comments belong in the latest thread.
The second thread has now also exceeded 500 comments, so after 42 chapters of MoR it's time for a new thread.
From the first thread: