▁charge ▁by ▁lic ensed ▁amateur ▁radio ▁operators ▁for ▁voice ▁( FM , ▁S SB ) ▁and ▁data ▁( AX . 2 5 , ▁packet ▁radio , ▁A PR S ) ▁communic ations . ▁Currently , ▁over ▁ 1 8 ▁fully ▁oper ational ▁amateur ▁radio ▁sat ell ites ▁are ▁in ▁orbit . ▁They ▁act ▁as ▁repe aters , ▁as ▁linear ▁trans pond ers , ▁and ▁as ▁store ▁and ▁forward ▁digital ▁rel ays . ▁ ▁Am ateur ▁radio ▁sat ell ites ▁have ▁helped ▁advance ▁the ▁science ▁of ▁satellite ▁communic ations . ▁Cont ribution s ▁include ▁the ▁launch ▁of ▁the ▁first ▁satellite ▁voice ▁trans ponder ▁( OS C AR ▁ 3 ) ▁and ▁the ▁development ▁of ▁highly ▁advanced ▁digital ▁" store - and - forward " ▁mess aging ▁trans ponder ▁techniques . ▁ ▁The ▁Am ateur ▁Radio ▁Sat ellite ▁community ▁is ▁very ▁active ▁in ▁building ▁sat ell ites ▁and ▁in ▁finding ▁launch ▁opportun ities . ▁List s ▁of ▁function ing ▁sat ell ites ▁need ▁updating ▁regularly , ▁as ▁new ▁sat ell ites ▁are ▁launched ▁and ▁older ▁ones ▁fail . ▁Current ▁information ▁is ▁published ▁by ▁A MS AT . ▁ ▁History ▁ ▁OS C AR ▁ 1 ▁▁ ▁The ▁first ▁amateur ▁satellite , ▁simply ▁named ▁OS C AR ▁ 1 , ▁was ▁launched ▁on ▁December ▁ 1 2 , ▁ 1 9 6 1 , ▁bare ly ▁four ▁years ▁after ▁the ▁launch ▁of ▁the ▁world ' s ▁first ▁satellite , ▁S put nik ▁I . ▁ ▁The ▁beginning ▁of ▁this ▁project ▁was ▁very ▁hum ble . ▁