Vostok Observatory is a Grimoire card from the original Destiny (Destiny 1), found under Places → Earth. Grimoire cards held most of the game's lore and were read on Bungie.net and in the companion app, not in the game itself.
Card text
Vostok Observatory Historical Society welcomes [––] from the Gondola it is possible [––] late Soviet space programs were converted to [––] research facilities to study accelerated methods of colonization [––] kid’s holobadges to remember your trip.
Grimoire text written by Bungie, shown as it appears in the Destiny 1 game files.