NEWTOWN, Conn. - The Space Launch System (SLS) is part of NASA's flagship program to revitalize deep space exploration. Despite the inspiring mission, the SLS has a troubled history and lacks a clear guide for future usage.
For much of the program's history, controversy surrounded the SLS. Even after a compromise was reached in the FY10 budget to fund both the SLS and commercial launch vehicles, NASA and Congress continue to battle over funding. Republicans in Congress may be placated by the decision by the new Trump administration to increase funding for the SLS, reducing some of the controversy going forward.
Even as the program faces the benefit of potentially moderating controversy, delays continue to mount. Originally planned to launch in 2017, the first launch was pushed back to late 2018. Even then, delays continued, pushing the first launch to 2019 at the earliest. Delays have been caused by problems with the development of the Orion service module as well as the SLS core stage. However, most engineers say that there was no single debilitating delay. Instead, many smaller problems have cascaded to produce large years-long delays.
Despite these problems, not all is bleak for the SLS. NASA completed the System Requirements Review and System Definition Review in July 2012. The SLS successfully passed its Preliminary Design Review in July 2013. Flight software and avionics were tested in December 2013. Booster avionics tests took place in April 2014, followed by forward skirt tests in May 2014. In July 2014, Boeing was awarded a $2.8 billion contract to develop the SLS core stage. The program completed the KDP-C in August 2014 and the Critical Design Review was completed in October 2015. Progress on the engines and upper stage also continues. Ground qualification testing for the SRB took place in March 2015 and June 2016, and the RS-25 underwent ground tests in 2015 and 2016, while the Exploration Upper Stage (EUS) passed its preliminary design review (PDR) in January 2017.
NASA has also started to make progress on finding a role for the SLS as the agency lays out future exploration strategies. NASA would like to build a system of deep space transports that support a gateway near the Moon, which would serve astronauts and crewless missions to deep space. As the largest launch vehicle in government service, the SLS would play a major role building and supplying the deep space gateway.
The first SLS launch is now expected to take place in 2019. Another launch will occur in 2022, and launches will become more consistent after that, with a launch taking place about every other year throughout the 2020s and 2030s.