The launch will take place on Wednesday at the John F. Kennedy Space Center on Merritt Island. President Richard Nixon was at KSC for the November 1969 launch of Apollo 12, the second mission to land astronauts on the moon.
The Demo-2 mission will be the final major step before NASA's Commercial Crew Program certifies Crew Dragon for operational, long-duration missions to the space station. Before leaving for Florida, Hurley said: "It's an incredible time for Nasa and the space programme as it again launches United States crews from Florida, hopefully in just a week from now".
Presidents have rarely attended NASA launches.
A similar fate could befall Trump and Pence. In addition to the risk of technical problems scrubbing a launch, weather forecasts are not promising, with one by the 45th Space Wing released May 23 projecting only a 40% chance of acceptable conditions.
Now that the flight readiness review and the static-fire test have been checked off the to-do list, the next big event on the agenda is Saturday's "dry dress rehearsal", which will involve going through the launch-day schedule without fueling up and firing the rocket.
NASA has also restricted the number of media credentials for the launch and changed media opportunities.
NASA still hasn't decided how long the astronauts will stay in space. NASA has provided special "virtual guest" content on its website and social media channels.
The two Nasa test pilots - Hurley and Behnken - will arrive on the launchpad about three hours before the launch in Tesla Model X Sports Car, ditching the traditional "Astrovan".
Local officials in Florida's Space Coast region have provided mixed messages.
In the age of coronavirus, Florida officials and NASA are split on whether it's a good idea for spectators to show up for next week's space launch. Such hotels would ordinarily be fully booked for a launch as significant as this. "It's only the fifth time that people have been launched on a new US spacecraft", John Logsdon, a professor emeritus at George Washington University's Space Policy Institute and former member of the NASA Advisory Council, told ABC News.
NASA astronauts are scheduled to fly on SpaceX's Crew Dragon spacecraft on May 27, lifting off from the Kennedy Space Center complex at Cape Canaveral. (Gregg Newton/AFP via Getty Images) A Falcon 9 SpaceX heavy rocket lifts off from pad 39A at the Kennedy Space Center in Cape Canaveral, Fla on February 6, 2018. "They're encouraging Americans to watch from afar, but I want to assure you that the president and I are looking forward, looking very much forward, to cheering you on".