WASHINGTON — A report from NASA’s Office of Inspector General (OIG) April 13 concluded that the first two missions of the Space Launch System rocket and Orion spacecraft will likely slip from their currently scheduled dates.

The report on NASA’s human exploration programs, the outcome of a nine-month audit by OIG, also recommended that NASA provide more details about its long-term plans to send humans to Mars, citing constrained budgets and the need to develop a number of key technologies to enable such missions.

NASA’s current schedule calls for the launch of the first SLS/Orion mission, Exploration Mission 1 (EM-1), no later than November 2018 without a crew. That would be followed by EM-2, the first SLS/Orion mission to carry astronauts, as soon as August 2021.

The OIG report, though, was skeptical NASA could maintain that schedule. “NASA’s first exploration missions – EM-1 and EM-2 – face multiple technical challenges that will likely delay their launch,” the report stated.

The report outlines a number of technical challenges that SLS, Orion and associated ground systems are facing that makes it unlikely NASA can maintain its current schedule for those missions. Work on SLS, it said, has consumed nearly all of the 11 months of schedule reserve it originally had. “With only 30 days of schedule reserves available, the SLS Program may be hard pressed to meet a November 2018 launch date,” OIG concluded.

Orion also faces issues. “NASA considers Orion to be one of the biggest challenges to meeting the EM-1 flight date of no later than November 2018,” the report stated. Delays in the development of the Orion service module, provided by the European Space Agency are the leading factor in the overall Orion delay, as well as technical risks involved with changes in the design of Orion’s heat shield.

In addition to SLS and Orion issues, the OIG report stated that work on ground systems at the Kennedy Space Center has only one month of schedule reserve remaining. Development of software needed for SLS, Orion and ground systems have also suffered delays that could delay the first SLS/Orion launch. “We are concerned NASA will not be able to resolve all necessary [exploration systems] software validation and verification efforts in time to meet a November 2018 launch date for EM-1,” OIG said in the report.

Recent events could exacerbate those delays. The report briefly mentions damage from a Feb. 7 tornado that hit the Michoud Assembly Facility in New Orleans. It estimated repairs to Michoud buildings could result in a two-month delay in work on the SLS, whose core stage is built there.

NASA officials have provided similar estimates on the potential delays caused by the tornado. “The tornado probably cost us two to three months,” said Bill Hill, deputy associate administrator for exploration systems development, in a March 29 presentation to the NASA Advisory Council’s Human Exploration and Operations Committee. “We’re still evaluating that and seeing what the options are.”

Another wild card that could delay EM-1 is a decision to put a crew on that first flight. NASA is currently examining such a move, which would delay the mission regardless of other technical issues. The target date for a crewed EM-1 mission is mid-2019, according to ground rules for that study cited in the OIG report.

The report said that, as of early April, the study about putting a crew on EM-1 was still in progress. “To achieve a crewed EM-1 flight, in our judgment NASA must address not only the additional risks associated with human travel but also a host of existing risks to planned missions,” OIG said in the report, citing work needed on Orion’s life support systems and a decision to either human-rate the Interim Cryogenic Propulsion Stage that will be used on EM-1 or accelerate work on the Exploration Upper Stage.

Beyond EM-1 and EM-2, OIG called on the agency to provide more details on future missions and technology requirements needed to enable the long-term goal of human missions to the surface of Mars. Only recently has NASA started to flesh out a manifest of future SLS/Orion missions, primarily for flights through the 2020s to develop a cislunar “gateway” station in preparations for Mars missions.

“While we agree that finalizing requirements for the Journey to Mars through 2046 is impractical at this point in time, we believe that adding more detail to the plan would help NASA focus funding priorities for the systems the Agency will need to develop to accomplish its goals,” the report stated.

That planning is needed soon because of concerns of a potential shortfall in funding. A comparison of projected budgets for NASA’s exploration programs, assuming they grow at only the rate of inflation, compared to the cost estimate from a Jet Propulsion Laboratory study of one proposed Mars mission architecture, found a gap of $18 billion from 2018 through 2026.

Another factor in that planning is a potential extension of the International Space Station beyond 2024, which could cost NASA $3 to 4 billion a year that would otherwise go to exploration programs.

“Whether to extend the ISS beyond 2024 is a critical decision for NASA and its Journey to Mars, particularly because of the funding shortfalls projected during the 2020s and the need for development of key systems during that time period,” the report argued.