Just three weeks ahead of liftoff, NASA and launch provider United Launch Alliance (ULA) announced that NASA’s Mars 2020 rover, Perseverance, and its Martian helicopter sidekick, Ingenuity, were mated with the Atlas V 541 rocket that will kick off the seven-month journey to the Red Planet. The precious cargo encapsulated inside of a protective payload fairing was carefully hoisted by crane operators to rest atop the Atlas V rocket. The payload joins the Atlas V common core booster, four solid rocket boosters, and the Centaur upper stage to achieve the stack’s final flight configuration height of 197 feet (60 meters).

The final stacking procedure was completed inside of the Vertical Integration Facility (VIF) at Cape Canaveral Air Force Station’s Space Launch Complex 41 (SLC-41). The rocket and payload will remain inside the protective structure and complete final check out tests until it is time quite literally roll to the launchpad. Crane operators first set down the payload for a soft touch to begin final full physical and electrical connection. The spacecraft and rocket will undergo integrated electrical testing as well as a battery of other tests as separate spacecraft and simultaneously as one complete unit.

On Friday (July 10), ULA president and chief executive officer, Tory Bruno, stated on Twitter that the Integrated Systems Test (IST) had been completed successfully. According to a previous mission statement posted to the ULA blog site, the IST is a typical pre-launch run down of the various connected systems between the spacecraft and launch vehicle to “verify proper functionality of launch vehicle systems, (and) conduct a simulated countdown and run through the launch sequence.”

The launch vehicle and integrated payload will remain inside the VIF undergoing mission-specific activities and final system checkouts over the next two weeks. Once all pre-flight activities have been successfully completed, approximately two days ahead of the scheduled launch attempt, the entire stack located on top of the Mobile Launch Platform will make the 1,800ft (550 meters) trip to the SLC-41 launchpad which will take about forty-minutes on a modified railway.

Known as an astrobiology mission and outfitted with seven instruments, the Perseverance rover will conduct new science, sample collection, and test new technology in search of ancient microbial life on the distant planet. The rover will spend the length of one Martian year – two Earth years – exploring the region around its landing site. It will collect and cache samples of the Martian surface to possibly be collected and returned to Earth by future joint missions currently under consideration by NASA and the European Space Agency.

The first interplanetary helicopter, Ingenuity, is a small 4-pound (1.8 kilograms) autonomous solar-powered aircraft that will conduct a series of experimental test flights. Ingenuity is traveling to Mars solely for a demonstrative mission and is not connected to the Perseverance rover by any means other than hitching a ride to the Red Planet. The new technology will demonstrate an ability to create lift in the thin atmosphere and lower gravity environment of Mars to help inform future aerial exploration and science delivery missions.

Currently, NASA and ULA are targeting the launch of the interplanetary mission on July 30th at 7:50 am EDT/4:50 PDT. Should they be necessary, multiple backup launch opportunities are available until the close of the interplanetary launch window on August 15th. Regardless of the launch date, after a seven-month-long, 290 million mile (467 million kilometers) journey – the rover and helicopter will arrive at Mars’s Jezero Crater, the home to an ancient Martian river delta, for a landing attempt on February 18, 2021. The landing date is perhaps even more crucial than the launch date as mission planners must take into account landing site lighting and temperature conditions and the locations of Mars-orbiting satellites required to relay crucial mission-specific information back to Earth.

Should the launch have to abort, and the 2020 window is missed completely, the robots will have to wait until 2022 when Earth’s orbit lines up just right with that of Mars, and the next interplanetary launch window opens up.