Nexus is a network of computer terminals given by the MTC to scientists working on Overlord. It was designed by Larry Hammond, consisting of a central computer and 8 terminals. He also made a failsafe mechanism which would cause the whole system (and the satellite) to self-destroy.
Access to the Nexus requires a passcard and password. All terminals also had the game Pong installed, which loaded with the use of password pong.
Fletcher discovered several possible passwords: isbpho, ueqne, lasentolw, nodgar, gnop, nikg, oork, napw, ehcetmack, bmgtai, etsaelmatslctae, niktgh, clbak, tewih.
These mean: bishop, queen, stonewall, dragon, pong, king, rook, pawn, checkmate, gambit, stalemate, castle, knight, black, white.