The momentum of certifying American space transportation systems capable of carrying astronauts to the International Space Station continued on pace as NASA took a comprehensive look at all of Boeing's ground-based system designs.

This Ground Segment Critical Design Review marks the second milestone in the company's Commercial Crew Transportation Capability (CCtCap) contract, NASA's Launch America initiative designed to return human spaceflight launches to the United States and end our reliance on Russia.

The three-week-long review covered Boeing's plans for constructing and processing its Crew Space Transportation System, called the CST-100, in a former orbiter processing facility at NASA's Kennedy Space Center in Florida, where Boeing will process its CST-100. It also covered the development of a nearby mission control center that would be the hub of the company's engineering operations.

"Along with facility designs, we looked at the operation processes," said Dave Allega, a lead in the Ground and Mission Operations Office of NASA's Commercial Crew Program.

"How would they be using those facilities? What is the flow? How are they going to build up their new spacecraft, get it ready to fly, put it on the launch vehicle and then operate it once it is there? Then, after landing, how will they go recover it and turn it around to go and do it again?"

A few dozen engineers, along with safety and health and human performance experts, took a deep dive into the various elements here on the ground that would support a crew mission to the station.

Even astronauts who could one day fly aboard the CST-100 participated in the review of these critical elements, such as how Boeing would test flight hardware, and assemble and integrate its spacecraft to the United Launch Alliance Atlas V rocket. They even looked at the equipment that would move the integrated stack to Cape Canaveral Air Force Station's Space Launch Complex 41.

"ULA has a long history of successful uncrewed commercial launches, and now they are highlighting what is different about flying a crew," said John Mulholland, Boeing Commercial Crew Program Manager.

Another critical piece of this review included how Boeing plans to train astronauts prior to missions and how the company will monitor crew members during all phases of the flight.

For example, the CST-100 spacecraft simulator the company built at its Houston Product Support Center will start to see a lot of action as more pilot-in-the-loop demonstrations are performed and crew training begins.

"The CST-100 will be a more simple vehicle to operate than the space shuttle, but the automation is complicated in and of itself, so we need to understand that automation and so does the crew," said Allega. "When Boeing trains our astronauts, they will have to balance simplicity, and giving the crew everything they need to know to manually operate the spacecraft just in case something goes wrong."

As part of its Launch America initiative, NASA selected Boeing and SpaceX to finalize their respective space transportation system designs, then build and fly test flights with crews to the station over the next few years.

For actual crew transportation missions to the ISS, the CCtCap contract requires crew handover to NASA within one hour of landing, which is why Boeing is looking at bringing the CST-100 home to land on terra-ferma in the Western United States using parachute and then utilizing airbags to soften the final touchdown.

This means for the first time since the end of NASA's Space Shuttle Program, agency managers, program managers and medical teams won't need to leave the United States to greet astronauts returning from space.

"This critical design review was validation to the NASA team that all of Boeing's ground segment plans are in place and are starting to match up to our certification requirements," said Kathy Lueders, manager of NASA's Commercial Crew Program. "This is a really good sign that we're marching at a good pace to reach our goal of certifying the system to fly to the space station."