NASA's Commercial Crew Program is turning to a number of strategies to work through the complex challenges of engineering a new generation of rockets and spacecraft. Technical Interchange Meetings, for example, are providing program leaders an opportunity to gain a comprehensive understanding for the vehicles that private industry are designing and developing on their own before the agency's astronauts will climb aboard.

Called TIMs for short, the meetings bring together a rather small group of experts to do just what its namesake calls for, exchange technical information. Alliant Techsystems Inc., or ATK, which is developing its Liberty launch vehicle under NASA's Commercial Crew Development Round 2 (CCDev2) activities, most recently held a TIM on the software that controls all the avionics components, commanding them to work together to control the launch vehicle.

"A TIM is really just an opportunity to fill in any holes associated with a review of these systems," said Ken Tenbusch, the NASA partner manager working with ATK. "We might see something and both teams kind of recognize, hey, maybe we just need to talk this out and vet it out a little bit further with some of our technical teams. So, what it does is it just opens up that line of communication back and forth."

The software TIM was the latest in a series for ATK under CCDev2. Earlier TIMs involved the company's planned approach to certifying the rocket's launch abort system and providing analysis of thrust oscillation to show the company could reduce the acceleration astronauts would experience during launch compared to ATK's Ares I rocket design, which has a similar architecture to Liberty.

"It's kind of like trying to determine why your car might be getting 20 miles of gasoline per gallon instead of 30," said James Burnum, NASA's deputy partner manager working with ATK. "It may take four or five experts to pull together the full story, someone who knows about the engine, someone who knows about the fuel, someone who knows about tires."

Typically the meetings take place in an informal type setting with a range of 15 to 30 experts. On the NASA side, the program is able to pull from a wide range of talent, including safety and integration engineers or teams working on the Space Launch System, the heavy-lift rocket designed to expand human presence beyond low Earth orbit.

Tenbusch said these meetings are nothing new to the spaceflight industry. In fact, while Tenbusch worked with the space shuttle's external fuel tank and solid rocket boosters as an operations manager he participated in dozens of TIMs. The major difference, he said, is the wealth of information that's being shared.

"During shuttle, both sides of the house already knew the answers and we would just get together to make sure we fully understood how we got to those answers," Tenbusch said. "With commercial crew, we've gone a little bit further, we've learned a little bit more about the company's systems and subsystems because they're bringing more information to the table."

All of NASA's CCDev2 partners are giving the agency an in-depth look at their vehicles during the joint venture of establishing routine access to and from the International Space Station in a few years.

Last week, for instance, Space Exploration Technologies, known as SpaceX, hosted a TIM at its headquarters in Hawthorne, Calif., to talk about the current design state of the crewed version of its Dragon capsule. Future interchange meetings could focus on topics such as abort aerodynamic loads and performance, and humidity and carbon dioxide removal systems.

Tenbusch said the companies also are welcoming the constructive feedback NASA provides at these meetings based on its decades of human spaceflight experience and the tough lessons it has learned about keeping crews safe.

"These companies want to be safe," Tenbusch said. "They want to be successful. They have to be successful and there's been a lot of ground gained from these TIMs."

"Failure is not an option for the commercial folks as it could very well put them out of business," Burnum added. "So, they're not going about this in a loose, casual manner, they're being very diligent every step of the way."