NASA said Wednesday the initial flight of its Space Launch System (SLS) heavy lift, exploration class rocket would be pushed back until no later than November 2018, 11 months after its original December 2017 goal.

The civil space agency said it performed a review called Key Decision Point C (KDP-C), which provided a development cost baseline of $7 billion for a 70-metric ton version of SLS. This runs from February 2014 through the first launch and a launch readiness schedule based on the November 2018 goal for first flight.

Artist's illustration of NASA's Space Launch System (SLS) heavy lift launch vehicle concept. Photo: NASA.
Artist’s illustration of NASA’s Space Launch System (SLS) heavy lift launch vehicle concept. Photo: NASA.

For its first test flight, SLS will be configured for the 70-metric ton lift capacity and will carry an uncrewed Orion spacecraft beyond low-earth orbit (LEO). In its most powerful configuration, SLS will provide a lift capability of 130 metric tons.

The Government Accountability Office (GAO) warned in a July report that NASA could miss its December 2017 goal because it was not on path to reach this milestone at the required confidence level of 70 percent, a key performance metric. GAO also noted, according SLS’ risk analysis, NASA’s funding plan could be $400 million short of what the program needed to launch by 2017 (Defense Daily, July 24).

NASA Associate Administrator Robert Lightfoot said Wednesday in a conference call the agency reached a 70 percent confidence level with its $7 billion budget and November 2018 launch goal. He added that SLS is the first time NASA reached 70 percent confidence for a human spaceflight program.

Lightfoot said SLS ground systems will be the next to go through a KDP-C evaluation, then the Orion multi-purpose crew vehicle in early 2015. Following those two milestones, Lightfoot said NASA will then bring the three elements together–rocket, Orion and ground systems–to assess readiness of the first launch.

SLS is NASA’s advanced, heavy-lift launch vehicle intended for deep space exploration to destinations including an asteroid and Mars. SLS will carry the Orion multi-purpose crew vehicle as well as important cargo, equipment and science experiments. Orion is scheduled to carry up to four astronauts beyond low earth orbit (LEO) on long-duration, deep space mission and include both crew and service modules and a launch abort system to significantly increase crew safety.

NASA said in its statement that the approval of SLS’ progression from formulation to development is something no other exploration class vehicle has achieved since the agency built the space shuttle. Lightfoot said in a statement SLS is on track to send humans to Mars by the 2030s.

The program delivered in April the first piece of flight hardware for Orion’s maiden flight, Exploration Flight Test-1, targeted for December. This stage adapter is of the same design that will be used on SLS’ first flight, called Exploration Mission-1. The next phase of development for SLS is the critical design review (CDR), a programmatic gate that reaffirms NASA’s confidence in the program planning and technical risk posture.

Commercial space company Space Exploration Technologies Corp. (SpaceX) is developing its own heavy lift launch vehicle called Falcon 9 Heavy with a first launch goal of 2015.