Two astronaut walkways, actually called “crew access arms,” are now installed at their respective launch pads in Florida, bringing NASA’s Commercial Crew Program one step closer to crewed flights. They are the first new crew access arms to be built at the cape since the Apollo era.
Crew access arms are basically walkways that astronauts use to board the space capsule they will be riding in, similar to the jetways that connect airport lounges and airliners. They consist of the walkway, itself and the white room. Attachment of the crew access arms is essential to the overall mission.
White Rooms are a longstanding fixture of human flights into space by NASA. They are basically clean rooms that prevent contaminants such as dirt, dust or stray hair from getting inside a spacecraft where, in zero-gravity, the contaminants could float up and jam behind instrument panels or be inhaled by astronauts.
Space Launch Complex 41 – Boeing CST-100 Starliner
The Crew Access Arm and White Room for Boeing’s CST-100 Starliner were attached to the Crew Access Tower at Cape Canaveral Air Force Station’s Space Launch Complex 41 on August 14, 2018.
Standing about 200-feet-tall, the Crew Access Tower was built for Boeing and ULA by Hensel Phelps and numerous other companies. It was erected in modular sections that had been built four miles away and outfitted with stairs, cable trays, and other fixtures. The work took about three months.
The steel Crew Access Arm and aluminum White Room together reach about 50 feet and weigh about 90,000 pounds. An environmental seal also will be added at the end of the White Room to fill the gap between the spacecraft and white room and provide for a pressurized clean room around the Starliner hatch.
The walkway and white room still have to go through tests, and a mock CST-100 has been put in place as it would at the launch pad to complete the evaluations. Once tested, the arm will act as a bridge from the tower to the spacecraft at the top of the rocket, almost 200 feet above the launch platform.
Launch Pad 39A – SpaceX crew Dragon
On Monday, August 20, the walkway astronauts will use to board SpaceX’s Crew Dragon capsule before missions to the International Space Station was added to historic launch pad 39A.
Readers may remember that SpaceX leased the launch facility, the former site of Saturn 5 and space shuttle blastoffs, from NASA in 2014. Since that time, SpaceX has modified pad 39A to facilitate the launch of the company’s Falcon 9 and Falcon Heavy rockets.
Because the Falcon 9 is so much taller than the Space Shuttle, the crew access arm was installed at the 195 foot level on the launch tower, several stories higher than what was used for the Space Shuttle.
The shuttle-era rotating service structure at pad 39A had been demolished piece-by-piece over the past several years, leaving the launch tower as the only original structure. The pad’s fixed tower was needed for the crew access arm. Falcon 9’s assembly hangar was built over the crawler-way once used for Saturn 5 rockets and space shuttles moving to the launch pad.
SpaceX constructed their own retractable structure that serves as a Falcon 9 transporter, erector and umbilical tower. The company plans to launch the first uncrewed Crew Dragon spacecraft on a test flight to the space station as soon as November.
