Boeing has confirmed the completion of the Phase Two Spacecraft Safety Review of its Crew Space Transportation (CST)-100 spacecraft and the Critical Design Review (CDR) of the spacecraft's systems.

Boeing is developing the CST-100 as part of the U.S. National Aeronautics and Space Administration's (NASA) Commercial Crew Program. The spacecraft is intended to transport crew or cargo to Earth's lower orbital destinations like the International Space Station (ISS). The spacecraft is designed in a way to house to a maximum of seven-crew staff or a combination of both cargo and crew.

The Phase Two Spacecraft Safety Review comprised a total analysis of hazards that the spacecraft may get into, which involved recognizing life-threatening circumstances. The review also warranted that the design of the spacecraft reduces any possible safety risks. Boeing reveals that the completion of the review is a major milestone, which will enable the company to reach a final design for the spacecraft, its related components and launch vehicle.

Boeing suggests that software, propulsion, avionics, landing, docking and power systems were a part of the 44 separate CDRs, which was conducted for the overall review.

"The challenge of a CDR is to ensure all the pieces and sub-systems are working together," says John Mulholland, Boeing Commercial Crew program manager. "Integration of these systems is key. Now we look forward to bringing the CST-100 to life."

NASA also released a statement confirming the review conducted for CST-100. NASA confirmed that the CST-100 spacecraft design were per NASA's safety investigation process, which included details of the spacecraft hazard reports.

"The integrated critical design review demonstrated the design maturity of the integrated spacecraft, launch vehicle and ground systems are at their appropriate points," per a NASA statement.

It is very important for Boeing to have completed a key review of its design for the CST-100 spacecraft. The company is now the only one out of the four competitors to complete the work on time.

Blue Origin, SpaceX and Sierra Nevada Corporation are the other companies, which have partnered with NASA to develop spacecraft that are reliable, safe, and cost-effective to transport crew and cargo to the space.

Sierra Nevada Corporation and SpaceX have received extensions to complete their design reviews by May 2015, while Blue Origin is also working hard to put forward its design proposals to NASA.

A NASA spokesperson indicated that the space agency is planning to work with one or more companies towards the development of the next-generation spacecraft.