La sonda Voyager 2 della NASA risponde dallo Spazio interstellare: i responsabili della missione le hanno inviato un segnale e la sonda ha confermato di aver ricevuto la "chiamata" e ha eseguito i comandi. Lanciata nel 1977, la sonda due anni fa ha lasciato il Sistema Solare e ora è a più 18,8 miliardi di chilometri dalla Terra.
Il contatto è avvenuto per testare i nuovi componenti recentemente installati sulla Deep Space Station 43, l'unica antenna al mondo, che si trova a Canberra, in Australia, in grado di inviarle comandi. Da marzo scorso l'antenna non era operativa per un aggiornamento tecnico che ha riguardato anche due nuovi trasmettitori radio. Uno di questi, utilizzato per comunicare con Voyager 2, non era stato sostituito da oltre 47 anni.
A 43 anni dal lancio, la sonda continua a funzionare grazie ad una sorta di batteria nucleare (generatore termoelettrico a radioisotopi) che dovrebbe permetterle di restare ancora attiva fino al 2025. Se il suo viaggio nello Spazio dovesse continuare "indisturbato", tra 296'000 anni dovrebbe passare "vicino" alla stella Sirio, a una distanza di 4,3 anni luce.
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