SLS & Orion Delays Have Multiple Causes

Artist concept of the Block I configuration of NASA’s Space Launch System.  (Credit: NASA)

The Government Accountability Office (GAO) 2017 assessment of NASA’s 21 largest programs contained a stark warning: the agency was in increasing danger of slipping the first flight (EM-1) of the Space Launch System (SLS) and Orion Multi-Purpose Crew Vehicle scheduled for November 2018.

But, by the time the assessment was published on May 16, it was already outdated: NASA officials had already announced a delay to an unspecified time in 2019.

The space agency’s deep space human exploration program is composed of three programs: SLS, Orion and the Exploration Ground Systems (EGS) needed to support flights. The total cost of the programs is $23.78 billion, which breaks down as follows:

  • Orion — $11.28 billion
  • SLS — $9.69 billion
  • EGS: $2.81 billion.

The GAO report found a range of challenges facing all three programs, including delays in delivery of the European-supplied service module (ESM) for Orion, cost increases and technical obstacles in developing the SLS massive core stage, and design issues with the ground systems.

“The late delivery of the European Space Agency (ESA)-contributed service module (ESM) is one of the main reasons that the Orion program is at risk of missing the planned EM-1 launch date,” the GAO report states.

“Since the ESM’s critical design review in June 2016, the ESM delivery date has been delayed by 8 months to September 2017 with a risk of an additional 2-month delay,” the report adds. “According to program officials, the delays are largely due to late deliveries to the service module contractor and underestimating the effort needed to complete the service module itself.”

The challenges with SLS development include the strength of core stage tank welds, the potential of debris impacting the engines during launch, and delays in writing software needed to control the booster.

“NASA officials indicated they have identified and corrected the root cause of low strength welds in the core stage tanks and that welding of test articles has resumed,” the report states. “NASA is also determining the extent to which new materials within the booster can withstand the structural stress of the SLS launch environment due to effects of long-term storage prior to launch.”

The EGS program has also been running behind schedule due to a number of technical challenges.

“The Mobile Launcher—which supports the assembly, testing, and servicing of the SLS rocket and provides the platform on which SLS and Orion will launch—has experienced multiple technical challenges and delays,” the report states. “For example, in last year’s assessment, we reported that there were design issues with a connection between the Mobile Launcher and SLS. According to EGS program officials, these issues are still being resolved.

“The program is also tracking several schedule risks related to launch equipment testing, ground support equipment installation, and analysis and testing of the Mobile Launcher,” the report adds.

As with SLS, the ground systems are also experiencing delays with software.

“The Ground Flight Application Software (GFAS)—software that will interface with flight systems and ground crews—continues to face challenges due to delays in the other main EGS software effort and late deliveries from the SLS and Orion programs,” the report states. “Over half of the GFAS software releases have been delivered; however according to EGS program officials, some content has been deferred due in part to Orion and SLS software delays.”

Excerpts from the GAO report on the three programs follow.

Orion

Credit: GAO

Developmental Partner

The late delivery of the European Space Agency (ESA)-contributed service module (ESM) is one of the main reasons that the Orion program is at risk of missing the planned EM-1 launch date. ESA is responsible for designing, developing, and providing a service module—which provides air, water, power, and propulsion to Orion during in-space flight—for EM-1 and EM-2, the first crewed mission.

Since the ESM’s critical design review in June 2016, the ESM delivery date has been delayed by 8 months to September 2017 with a risk of an additional 2-month delay. According to program officials, the delays are largely due to late deliveries to the service module contractor and underestimating the effort needed to complete the service module itself. If NASA cannot mitigate these delays, it will likely miss the planned EM-1 launch date. According to program offices, the program needs 12 months to integrate and test the ESM with the crew module following delivery from ESA.

NASA officials stated the complete Orion crew vehicle must be delivered to Kennedy Space Center by July 2018 to maintain the planned EM-1 launch readiness date. The ESM delivery delays have also affected Orion software development and may negatively affect EGS’s schedule, which needs Orion software and modeling data to perform integrated testing.

Design

The Orion program has made progress in a key outstanding area of the crew vehicle design—the heat shield. The program redesigned the heat shield to improve its structural strength and has nearly completed production of the heat shield blocks for EM-1.

The program previously switched from a single piece, or monolithic, heat shield design to one that employs blocks similar in concept to those used on the Space Shuttle. The program plans to complete testing that will verify the blocks properly adhere and bond to representative crew module hardware by May 2017.

Integration and Test

According to program officials, testing for EM-1 is proceeding according to plan, but looming schedule delays could have a cascading effect on EM-2 due to the program’s test strategy. The program plans to perform testing for EM-2 using flight hardware from EM-1 in order to reduce costs, but this could pose a schedule risk.

Program officials said that this plan places the program at risk of significant delays for EM-2 should the crew module suffer damage during the first mission. To mitigate this risk, program officials stated that they have set aside time between EM-1 and testing for EM-2 to refurbish the spacecraft’s avionics and replace damaged parts with spares. If EM-1 is delayed, the schedule risks for EM-2 would increase.

Funding

The Orion program’s internal EM-2 cost goal of $10.8 billion and launch readiness date of August 2021 is not supported by NASA’s planned budget requests. To stay on this schedule, NASA is counting on receiving more appropriated funds than it plans to request.

Space Launch System

Credit: GAO

Cost and Schedule Status

The core stage development is the pacing item for the SLS program and its schedule is aggressive. For example, there is no schedule reserve remaining for core stage development leading up to the “green run” test scheduled for October 2017. This test is the culmination of the development effort and includes the core stage flight article integrated with four RS-25 engines that NASA plans to fire for about 500 seconds in a simulated flight profile.

If the test does not occur as scheduled or the stage does not perform as expected, core stage delivery to Kennedy Space Center could be delayed beyond the currently scheduled date of March 2018. The program only has 20 days of reserve between the end of the test and the date the core stage is needed at Kennedy Space Center for the start of integration.

Design

In July 2016, we reported that the SLS program had matured the launch vehicle’s design, but it is still working to address known hardware and software challenges. The program’s current hardware challenges include the strength of the core stage tank welds and booster-related issues.

NASA officials indicated they have identified and corrected the root cause of low strength welds in the core stage tanks and that welding of test articles has resumed. NASA is also determining the extent to which new materials within the booster can withstand the structural stress of the SLS launch environment due to effects of long-term storage prior to launch.

In addition, the SLS program is assessing the potential risk of damage from booster debris impacting the engines during launch. The program has efforts underway to further analyze or mitigate these and other issues.

The SLS program also has encountered delays with the development of SLS flight software due to the late delivery of core stage avionics models needed for testing. These development delays consumed software schedule reserves and affected the maturity of the 12th software release. The program has 14 planned software releases. Program officials said that the final software release was moved from 2017 to 2018 to allow for more testing, among other reasons.

Integration and Test

The SLS program must complete two distinct levels of integration—integration of the SLS launch vehicle and cross-program integration of SLS with Orion and ground support systems—before it can achieve launch readiness in 2018. The integration period often reveals unforeseen challenges leading to cost growth and schedule delays.

Contractor

The value of the SLS core stage development contract increased by $962 million in February 2017. The SLS program and Boeing reached agreement to modify the scope of the contract to develop, test and deliver a new exploration upper stage for the vehicle that the program plans to use during Exploration Mission-2.

Exploration Ground Systems

Credit: GAO

Design and Technical

The EGS program has completed several projects, including the Crawler Transporter and Launch Vehicle Offline Processing facility, but technical challenges and delays with the remaining work could put the overall schedule at risk.

The Mobile Launcher—which supports the assembly, testing, and servicing of the SLS rocket and provides the platform on which SLS and Orion will launch—has experienced multiple technical challenges and delays. For example, in last year’s assessment, we reported that there were design issues with a connection between the Mobile Launcher and SLS. According to EGS program officials, these issues are still being resolved.

The program is also tracking several schedule risks related to launch equipment testing, ground support equipment installation, and analysis and testing of the Mobile Launcher. The EGS program does not have any reserves to accommodate further Mobile Launcher delays, and program officials stated that they have nearly exhausted other options to stay on schedule, such as adding extra shifts.

The EGS program has also experienced delays with the development and testing of one of its two main software efforts. The Ground Flight Application Software (GFAS)—software that will interface with flight systems and ground crews—continues to face challenges due to delays in the other main EGS software effort and late deliveries from the SLS and Orion programs. Over half of the GFAS software releases have been delivered; however according to EGS program officials, some content has been deferred due in part to Orion and SLS software delays.

Due to the ongoing delays, the program may complete GFAS development as late as August 2018—6 months later than previously planned. EGS officials said this delay will not interfere with integrated testing and operations with SLS and Orion because key parts of the software, such as the launch countdown capability, will not be needed until later in the integration process. The EGS program is still tracking a risk that GFAS may not be ready when needed and it has hired additional staff as part of its efforts to address this risk.

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