Another major hardware component for Boeing's second Starliner spacecraft recently arrived at the company's assembly facility at NASA's Kennedy Space Center in Florida. The upper dome - basically one half of the Starliner pressure vessel - arrived at the Commercial Crew and Cargo Processing Facility, closely following the arrival of the lower dome and docking hatch in early May.

The three components will be outfitted separately with wiring and lines, avionics and other systems before the pieces are connected to form a complete Starliner the company is calling Spacecraft 1. From there, it will be outfitted with electrical and fluid systems before engineers will attach the outer thermal protection shielding and the base heat shield that will protect the crew during re-entry.

The upper and lower domes are distinctive with the honeycomb pattern machined into the aluminum to reduce weight and increase strength to handle the flight stresses. The domes are created using a weldless spin forming process that is then machined into the honeycomb pattern.

Later, engineers will use bolts to connect the upper and lower domes for final outfitting. It takes a team of Boeing suppliers across the country to develop the domes before they arrive in Florida, including Spincraft based in North Billerica, Massachusetts, performing the spin-form work, Janicki Industries in Layton, Utah, machining the lower domes and Major Tool and Machine in Indianapolis machining the upper domes.

This vehicle will be the first Starliner to fly in the company's pad abort test to prove the launch abort system planned for the spacecraft will be able to lift astronauts away from danger in the event of an emergency during launch operations. The test is planned to occur prior to true flight tests of the Starliner atop a United Launch Alliance Atlas V rocket.

NASA's Commercial Crew Program contracted Boeing to build the Starliner as part of the effort to return America's ability to launch crews to the International Space Station. The agency also selected SpaceX to build that company's Crew Dragon which will also deliver astronauts to the space station.

Currently, only Russian Soyuz spacecraft are able to take astronauts to the orbiting laboratory where research is under way in numerous disciplines that will improve life on Earth and to understand and find solutions for the challenges that astronauts will face in the future on deep space missions.

The work on this Starliner is beginning as the Boeing team finalizes construction of the first Starliner, a structural test article that will be used for ground testing. The NASA and Boeing teams will compare test results to the requirements and expectations for the spacecraft as it nears flight tests with and without crew members aboard.

After completion of assembly at Kennedy, the structural test article will be shipped to Huntington Beach, California, where it will be subjected to numerous structural tests including a modal survey, critical load conditions, structural integrity, ordnance-actuated shock levels and the performance of the system that will separate the crew module from the service module.

Thermal, vacuum, and electronic interference chambers will be used to evaluate aspects of the Starliner's ability to withstand the rigors of flying astronauts in the hazardous environment of low-Earth orbit. The service module for the test article was shipped at the end of May to Huntington Beach and is expected to be joined by the spacecraft in June.

The service module, which is discarded at the end of the mission just before the Starliner and crew descend into Earth's atmosphere and land, holds propellant tanks along with the four large launch abort system engines that will push a Starliner and its astronauts out of danger in the unlikely event of an emergency during launch countdown or on ascent into space.

Starliners will fly into space aboard Atlas V rockets built by United Launch Alliance. Space Launch Complex 41 at Cape Canaveral Air Force Station, a few miles south of the Starliner assembly building, is being modified to host astronauts to enter the spacecraft and their ground support team ahead of a launch.

The Crew Access Tower's main structure is complete and the Crew Access Arm will be installed later this year. Boeing is targeting 2017 for an uncrewed orbital flight, then a flight test with astronauts in early 2018 that will dock with the space station before returning to Earth.