Boeing’s CST-100 takes shape at former NASA facility

Joe Latrell

The Commercial Crew transportation Capability (CCtCap) phase of NASA’s Commercial Crew Program continues to advance at a steady pace. This week, two major components arrived for Boeing’s Crew Space Transportation 100 (CST-100) spacecraft at a processing facility located at NASA’s Kennedy Space Center in Florida. The arrival of these parts marks just the latest step in the space agency’s efforts to cede the responsibility of sending crews into orbit via spacecraft produced by private firms.

The components that arrived at KSC are two domes that will form the pressure shell of the new spacecraft.

This version of the vehicle is known as the Structural Test Article or STA. It is designed to test the design for effectiveness. It will also be used in a pad abort test similar to the one performed by SpaceX with their crewed Dragon vehicle.

The STA is not designed to carry astronauts. Instead, it will fly with an extensive collection of sensors and data-gathering equipment. Getting a crew to safety in the event of an emergency is a critical requirement for the Commercial Crew Program.

Work on the STA is being performed at the former Orbital Processing Facility 3 where NASA’s shuttles were processed before heading to the VLA for mating with the boosters. Boeing has refurbished the facility to test and validate manufacturing and processing methods for the CST-100. Once the STA version of the CST-100 is complete, it will travel to Huntington Beach, California, for further testing and evaluations.

The STA main structure was friction-stir welded into a single upper and lower hull component. The assembled unit was then machined to the finished thickness. Friction-stir welding is a relatively new technique used in aerospace. Instead of using a traditional weld system that adds material, stir welding uses a computer-guided high-speed bit (similar to a drill bit) to fuse the parts together.

Championed by the now-defunct Eclipse Aviation, friction-stir welding has the advantage of a stronger bond that is less likely to fail due to weak or brittle spots caused by overheating. Since the manufacturing is computer-controlled, there is less material waste as well. The main structure is now being outfitted with flight critical components.

The CST-100 is Boeing’s entry that was selected for the Commercial Crew program. The vehicle is designed to carry up to seven astronauts and cargo to the International Space Station (ISS). It will use the new NASA Docking System, which is compatible with the International Docking Adapter (IDA) standard. Emergency abort will be provided by Rocketdyne RS-88 engines. The heat shield used to protect the craft during re-entry is a new design known as the Boeing Lightweight Ablator (BLA).

A test article of the CST-100 has already been drop tested from 11,000 feet (3,350 meters). A pad abort test is next followed by an unmanned test flight – both are currently slated to take place in early 2017. Crewed flights to the ISS should begin in late 2017. NASA recently selected the astronauts who will fly the first commercial crew missions; they were Robert Behnken, Eric Boe, Douglas Hurley, and Sunita Williams.

Cape Canaveral’s Space Launch Complex 41, only a few miles from the processing facility, is being re-engineered to accommodate a crew-rated access tower. The CST-100 will launch atop the United Launch Alliance Atlas V rocket from this site.