Al’Jazeera :  NASA has announced a rare, health-related delay in its SpaceX rocket launch of four astronauts to the International Space Station, the second postponement of the mission in a week, citing an unspecified medical issue with one of the crew.
 NASA said on Monday the issue was “not a medical emergency and not related to COVID-19,” but the space agency declined to elaborate on the nature of the problem or say which astronaut was involved.
 The launch, originally set for Sunday but then postponed until this Wednesday because of unsuitable weather conditions, has now been rescheduled for Saturday night, NASA said. The last time NASA delayed a scheduled launch over a medical issue involving the crew was for a Space Shuttle Atlantis flight in 1990 when mission commander John Creighton fell ill. The countdown was halted for three days until he was cleared to fly, according to NASA. That delay was followed by two additional weather-related postponements.
 For the time being, the four crew members will remain under routine quarantine at the Cape as they continue launch preparations, NASA said.