Focus on Details Paying Off for CST-100

 A scale model of a Boeing CST-100 on a United Launch Alliance Atlas V is tested inside a wind tunnel to evaluate the design and see how it will behave during launch and ascent into orbit. (Credit: The Boeing Company)
A scale model of a Boeing CST-100 on a United Launch Alliance Atlas V is tested inside a wind tunnel to evaluate the design and see how it will behave during launch and ascent into orbit. (Credit: The Boeing Company)

By Steven Siceloff,
NASA’s Kennedy Space Center

The Boeing Company in Houston is performing ongoing work to advance the design of the CST-100, a capsule and service module, in between meeting major milestones for NASA’s Commercial Crew Program. Boeing is one of three companies working with NASA to develop space transportation systems capable of flying astronauts to and from low-Earth orbit and the International Space Station later this decade.

“Now we’re seeing real flight-designed parts,” said John Mulholland, vice president and general manager of Commercial Program for Boeing. “We’re getting ready to move in with tooling to assemble a structural test article. We’ll be receiving our first piece of flight-designed hardware later this year. It’s getting exciting to watch real hardware coming off the manufacturing line.”

Boeing is working toward building a test version of the CST-100 at NASA’s Kennedy Space Center in Florida. The company plans to lease one of the facilities that formerly processed space shuttles for launch. Engineers and technicians will practice their procedures for assembling and processing the new spacecraft.

According to Mulholland, Boeing is focused on proving designs of the spacecraft are correct, from the big picture to the smallest element. That goes for plans covering the ground equipment that will support the spacecraft on the launch pad, plus operational plans for launch atop a United Launch Alliance Atlas V rocket and recovery.

“This phase is really a grind and it’s all focused on detailed execution and final design release,” Mulholland said. “It’s really interesting to sit back and watch the team evolve, which they’ve had to do really quickly.”

An important element in the project is a series of milestones and detailed evaluations, which include wind tunnel tests and design reviews that look at parts and systems large and small. Recent progress included a critical design review for the CST-100’s side hatch counterbalance, a device that makes opening and closing the door to the spacecraft less strenuous.

Boeing’s James “J.J.” Johnson, who leads the testing and evaluations of the CST-100, said designers do not see anything problematic at this point.

Wind tunnel testing at NASA’s Ames Research Center in California evaluated an 8-foot-long, 700-pound model of the CST-100 and the rocket it will fly on, the Atlas V. It experienced winds simulating flight at speeds from Mach .4 to Mach 1.3, well above the speed of sound. That speed, known as the transonic region, is where rockets typically encounter the most stress of launch since it occurs in the thick parts of the atmosphere inside a minute of launch.

“We wanted to see if our shape on an Atlas was viable,” Johnson said. “The information looks real good.”

Upcoming wind tunnel sessions are planned to test the spacecraft design and handling under different scenarios, including a launch abort and emergency landing.

Designers will develop models of the CST-100 as it will look riding on a dual-engine Centaur upper stage to find out what to expect during the spacecraft’s ascent to orbit. Dual-engine Centaurs helped send dozens of satellites and probes into orbit. Launching astronauts and launching aboard an Atlas V will be important firsts for the engine.

Johnson said the team will make about 8,000 test runs and gather more than 20,000 data points to find out how the spacecraft will separate from the Centaur, how the two will behave together as the engines fire and numerous situations in between.

In addition to the sophisticated hardware under development, engineers are making strides on the complex software needed to operate the spacecraft through every phase of flight.

“Flight software has historically been a hurdle that bites you late, so there is a lot of focus on our team to make sure we get that developed early,” Mulholland said.

The CST-100 computers are expected to perform many tasks autonomously, including rendezvous and docking with a space station or another spacecraft.

Under Space Act Agreements with NASA, Boeing is paid for successfully reaching certain milestones. NASA is closely involved with much of the work and contributes technical expertise throughout the process.

“We have really focused on making sure we hold schedule wherever we can,” Mulholland said. “What’s been really satisfying is that through May, every milestone we’ve completed on or ahead of schedule, which is really somewhat unique in a development program at this stage.”

The latest round of CCP agreements, known as the Commercial Crew Integrated Capability (CCiCap), ends with a successful critical design review of the entire space transportation system, clearing the way for the company to build the spacecraft for flight demonstrations.

NASA’s other CCiCap partners, Space Exploration Technologies Corporation (SpaceX) and Sierra Nevada Corporation, also are deep into development work on their respective space transportation systems: the Dragon and Falcon 9 integrated system and Dream Chaser and Atlas V combination.

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