A launch countdown includes “L Minus” to indicate how far away liftoff is in hours and minutes, and “T Minus” to show a sequence of events built into the launch countdown.
March 30 (UPI) --NASA officials on Monday started the two-day countdown to the Artemis II mission launch, which will send a crew of four around the moon as they test the Space Launch System rocket and ...
NASA started the countdown clock for Artemis II while SpaceX lined up another launch with a record-setting booster.