There are actually plenty of ftp-servers etc. in the U.S. and Europe, which host raw and pre-processed data of various instruments from old space exploration missions. Usually it is for free, although in a few cases one must leave a name and an e-mail-address before being granted access to the archives. Some of them host bits and pieces of old Soviet stuff too, such as data form Venera missions to Venus. But there is only very limited data on the internet as far as I have seen.
Does anyone know of websites, ftp-servers or similar, which host such data?
(I must admit, that I do not speak Russian, so I have a hard time googling through the depth of the Russian internet ...)