Last week NASA announced for the second time that it was pushing back the date. The rover launch was originally scheduled for 17 July, before being rescheduled for 20 July. The new shift from July 22 is necessary "because of a processing delay encountered during spacecraft encapsulation activities."
The #US space agency @NASA has delayed the launch of world's largest #spacetelescope 'James Webb Space Telescope' until May 2020; The most powerful space telescope ever built, the Webb telescope is considered to be the successor to NASA's 26-year-old #Hubble Space Telescope pic.twitter.com/NHsspbwjCC— Dhanraj Nathwani (@DhanrajNathwani) March 30, 2018
NASA expanded on the issue, saying, "There was a need for additional time to resolve a contamination problem in the ground support lines at NASA's Payload Hazardous Servicing Facility (PHSF)." NASA also released a photo of the packed-up rover at PHSF where it gets tucked into the fairings that will protect it during launch.
The slight delay is not a major concern as the start-up period extends until 11 Aug. The overall window however is critical. If NASA can't send the rover off in time, due to Earth's position in relation to Mars, it will have to wait until 2022 for its next chance.
Perseverance will take off from Florida's Cape Canaveral Air Force Station, with a United Launch Alliance Atlas V rocket assist. NASA is targeting a two-hour window for the July 22 launch starting at 6:35 am PT.
"Almost ready to go," a tweeted last week by the Perseverance rover team.
If everything goes well, on Feb. 18, 2021, Perseverance will arrive on the red planet to seek signs of past microbial life, drop off a helicopter and collect samples of Mars that may one day be brought back to Earth.