Astronauts participate in a Boeing/United Launch Alliance emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. The system features seats attached to slide wires which would carry astronauts and ground crew more than 1,300 feet away from the crew access tower in the unlikely event of an emergency prior to liftoff on launch day.

Astronaut Nicole Mann gets suited up for a Boeing/United Launch Alliance emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. The emergency egress system will allow for a safe evacuation in the unlikely event of an emergency on the launch pad on launch day. It can carry up to 20 people more than 1,300 feet away from the crew access tower and the launch vehicle.

Commercial Crew astronauts participate in a Boeing/United Launch Alliance (ULA) emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. The emergency egress system features folding seats attached to slide wires. In the unlikely event of an emergency prior to liftoff on launch day, each person on the Crew Access Tower would get his or her own seat and slide more than 1,300 feet to a safe area.

The 2017 class of astronaut candidates pose for a group photograph at United Launch Alliance's Space Launch Complex 41 at Cape Canaveral Air Force Station (CCAFS) in Florida during a familiarization tour. They also toured Kennedy Space Center facilities, including the Neil Armstrong Operations and Checkout Building high bay; the Launch Control Center, Launch Complex 39B, the Vehicle Assembly Building, Boeing's Commercial Crew and Cargo Facility, and SpaceX's Launch Complex 39A. The candidates will spend about two years getting to know the space station systems and learning how to spacewalk, speak Russian, control the International Space Station's robotic arm and fly T-38s, before they're eligible to be assigned to a mission.

Astronaut Suni Williams gets suited up in preparation for the Boeing/United Launch Alliance emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. The emergency egress system features seats that attach to slide wires. It can carry astronauts and ground crew more than 1,300 feet away from the crew access tower and the launch vehicle in the unlikely event of an emergency before liftoff.

The sun sets on Cape Canaveral Air Force Station’s Launch Complex 41 in Florida during a Boeing/United Launch Alliance (ULA) emergency egress system demonstration on June 19, 2018. The emergency egress system features folding seats attached to slide wires. In the unlikely event of an emergency on launch day prior to liftoff, each person on the Crew Access Tower would get his or her own seat and slide more than 1,300 feet to a safe area. The Boeing CST-100 Starliner will launch on a ULA Atlas V rocket, carrying astronauts to the International Space Station

The 2017 class of astronaut candidates are at United Launch Alliance's Space Launch Complex 41 at Cape Canaveral Air Force Station (CCAFS) in Florida for a familiarization tour. They are on the crew access tower that provides access to the crew access arm. They also toured facilities at Kennedy Space Center, including the Neil Armstrong Operations and Checkout Building high bay; the Launch Control Center, Launch Complex 39B, the Vehicle Assembly Building, Boeing's Commercial Crew and Cargo Facility, and SpaceX's Launch Complex 39A. The candidates will spend about two years getting to know the space station systems and learning how to spacewalk, speak Russian, control the International Space Station's robotic arm and fly T-38s, before they're eligible to be assigned to a mission.

The 2017 class of astronaut candidates are at United Launch Alliance's Space Launch Complex 41 at Cape Canaveral Air Force Station (CCAFS) in Florida for a familiarization tour. They also toured facilities at Kennedy Space Center, including the Neil Armstrong Operations and Checkout Building high bay; the Launch Control Center, Launch Complex 39B, the Vehicle Assembly Building, Boeing's Commercial Crew and Cargo Facility, and SpaceX's Launch Complex 39A. The candidates will spend about two years getting to know the space station systems and learning how to spacewalk, speak Russian, control the International Space Station's robotic arm and fly T-38s, before they're eligible to be assigned to a mission.

Chris Ferguson, Boeing’s Director of Crew and Mission Operations for their Commercial Crew Program, is helped into his suit in preparation for a Boeing/United Launch Alliance emergency egress system demonstration on June 19, 2018. A veteran of three space shuttle missions, he commanded Atlantis in STS-135, the final mission of the Space Shuttle Program. The demonstration was held at Launch Complex 41 at Cape Canaveral Air Force Station in Florida. The emergency egress system provides an escape route in the unlikely event of an emergency on the launch pad on launch day.

Astronauts participate in a Boeing/United Launch Alliance (ULA) emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. The system is designed to safely evacuate astronauts and ground crews in the unlikely event of an emergency on the launch pad on launch day. The Boeing CST-100 Starliner will launch on a ULA Atlas V rocket, carrying astronauts to the International Space Station.

An astronaut heads into a mine-resistant ambush protected vehicle, or MRAP, during a Boeing/United Launch Alliance emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. NASA’s MRAPs offer a mobile bunker for astronauts and ground crews, should they need to escape from the launch pad quickly in an emergency.

Two mine-resistant ambush protected vehicles, or MRAPs, sit ready to receive astronauts and ground crews during a Boeing/United Launch Alliance emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. The emergency egress system will provide an escape route in the unlikely event of an emergency on the launch pad on launch day.

NASA astronauts Bob Behnken and Suni Williams get suited up for a Boeing/United Launch Alliance emergency egress system demonstration at Cape Canaveral Air Force Station’s Launch Complex 41 in Florida on June 19, 2018. Behnken and other astronauts tested the system, which is designed to evacuate them safely in the unlikely event of an emergency on the launch pad on launch day. The Boeing CST-100 Starliner will launch on a ULA Atlas V rocket, carrying astronauts to the International Space Station.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket is seen on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

From left, NASA astronauts Barry “Butch” Wilmore and Suni Williams, Boeing Crew Flight Test (CFT) commander and pilot, speak with VIPs while watching Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket is seen on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket is seen on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket is seen on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

NASA astronaut Barry “Butch” Wilmore, Boeing Crew Flight Test (CFT) commander, watches Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket roll out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket is seen on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

NASA astronaut Barry “Butch” Wilmore, Boeing Crew Flight Test (CFT) commander, watches Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket roll out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket is seen on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket is seen on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.

Boeing’s Starliner spacecraft atop the United Launch Alliance Atlas V rocket rolls out from the Vertical Integration Facility to the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida on Saturday, May 4, 2024, ahead of NASA’s Boeing Crew Flight Test. As part of the agency’s Commercial Crew Program, NASA astronauts Butch Wilmore and Suni Williams are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff is scheduled for 10:34 p.m. ET Monday, May 6.