WASHINGTON, Dec. 8 (Xinhua) -- NASA and Boeing have completed Starliner's last parachute balloon drop test, ending a reliability campaign that will help strengthen the spacecraft's landing system ahead of crewed flights to and from the International Space Station.

The campaign, developed by both Boeing and NASA, used six balloon drop tests of a Starliner test article to gather supplemental performance data on the spacecraft's parachutes and landing system, according to a latest release of NASA.

Each drop test focused on a different set of adverse conditions and used pre-flown parachutes to evaluate reusability margins for future missions.

Starliner is the first American-made orbital crew capsule to land on land. The spacecraft uses a series of parachutes and airbags that deploy at specific altitudes allowing Starliner to touch down gently in the desert of the western United States.

NASA also will use the data gathered from the parachute testing to model Starliner parachute performance in different mission scenarios.

Boeing and NASA will continue collecting data on Starliner's parachutes through the spacecraft's second Orbital Flight Test ahead of crewed flights beginning in 2021, according to NASA.