Correct me if I am wrong but I thought you could log an attended to any space event cache and get the souvenir. The following is from OP's Geocaching in Space page.
6. Do I have to attend an official space event, to receive the "Geocaching in Space" souvenir ?
No. If you log your "Attended" for any geocaching event, that is held on November 6th or November 7th 2013 and listed on Geocaching.com, you will receive the souvenir. Events on both days will help commemorate Geocaching in Space.
Confused!
