An undocking glitch has delayed the departure of three astronauts from the international space station aboard a Soyuz spacecraft. NASA today said the trio – two Russians and one American- are now scheduled to return to Earth early tomorrow. They are expected to land in Kazakhstan. The delay means another day in space for Cmdr.Alexander Skvortsov and flight engineers Mikhail Kornienko and Tracy Caldwell Dyson. NASA said the opening hooks and latches on the docking port did not release. The preliminary evaluation by the Russians was that the micro-switches that interface with the Soyuz malfunctioned. The Russian flight controllers have developed a backup plan, and the resident crew of three is working to fix the malfunction.