Human spaceflight returns to US soil Wednesday

Following a Flight Readiness Review on Thursday, NASA’s SpaceX Demo-2 mission was cleared to proceed toward liftoff on the first crewed flight of the agency’s Commercial Crew Program. The mission follows the un-crewed Demo-1 mission. It also marks the first launch of humans from American soil since the final space shuttle mission lifted off on July 8, 2011.

Launch of the SpaceX Falcon 9 rocket and Crew Dragon spacecraft, carrying NASA astronauts Robert Behnken and Douglas Hurley to the International Space Station, is scheduled for Wednesday at 4:33 p.m. EDT from Launch Complex 39A at Kennedy Space Center in Florida.

While much of the process is the same, many things will look different.

The mission will launch from the the same historic launch pad that has launched 82 shuttle and 12 Apollo missions. Following the 2017 removal of the rotating service structure which provided access to the shuttle's cargo bay, a sleek new Crew Access Arm was added for crews to board the capsule.

One of the biggest changes SpaceX vehicles bring is in how they are brought together and brought to the launch pad.

Space Shuttles were "stacked" in the massive Vehicle Assembly Building and remained vertical as they were rolled out along the 3-mile path to the pad.

Space-X vehicles are assembled in a Horizontal Integration Facility (HIF) just outside LC39A fences. There Dragon capsules and other payloads are mated to the Falcon 9 rocket and remain horizontal as they are moved about four football fields to the pad where they are lifted to a vertical position.

To Hollywood costume designer Jose Fernandez, who also created the superhero costumes for Wonder Woman, Wolverine and Captain America: Civil War, this next generation of space suit doesn't just look good, it accommodates the needs of this next generation spacecraft.

While the flight deck of each space shuttle orbiter had more than 1,000 buttons, switches and other controls, most control of the Crew Dragon can be accessed through three flat screens. The additional 38 buttons beneath the screen are intended to provide backup control.

Gloves are touch-screen compatible and helmets were custom 3D printed. The suits provide flame-resistance and protection from capsule depressurization as well as cooling and communications.

When STS-9 brought larger crews and a need for a larger transport in 1983, Airstream modified a 28-foot Excella motor home which served through STS-135 in 2011.

Both versions of the astrovan are on display at the Kennedy Space Center Visitor Complex.

On Wednesday, astronauts will arrive in an electric vehicle. A pair of standard Tesla Model X vehicles with NASA logos and license plates that read "ISS BND" will ferry astronauts to the launch pad.

The NASA "meatball" on the doors and the red NASA logotype in use between 1975 and 1992 affectionately known as the "the worm" across the rear window. Also look for a worm logo on the Falcon 9 rocket.

Astronauts Hurley and Behnken indicated during a Friday press conference that they were planning to spend some time this Memorial Day weekend at the Beach House, one of the few original buildings left at Cape Canaveral when it was purchased in 1963 as a part of expansion of what would become the Kennedy Space Center.

Astronauts often name their spacecraft to honor individuals. Astronauts Hurley and Behnken indicated during a Friday press conference that they would continue this tradition, revealing their chosen name in the coming days.

NASA TV will provide extensive live coverage of Demo-2 events, all times are EDT.

Air Force forecasters at the Cape Canaveral Air Force Station will provide launch weather forecasts as they have going back to the shuttle days and beyond. Forecasters will be watching potential for winds, precipitation and lightning, not just for Florida but 50 locations along the flight path extending to Northern Ireland.

Launch delays most often come from weather concerns, especially when humans are onboard. Even wave height is being monitored to ensure that if crews have to abort the launch while in flight, they can come down into sea conditions that will keep them safe until rescue arrives.

This is also an instantaneous launch, which means there is no wiggle room in the launch window. Any delays will require the launch team to stand down until the following day.

In a word: don't.

“The challenge that we’re up against right now is we want to keep everybody safe,” NASA Administrator Jim Bridenstine said. “we’re asking people not to travel to the Kennedy Space Center