GAO Finds Concerns About Structural Integrity of SLS Mobile Launcher

Mobile crawler transporter (Credit: NASA)

Updated May 5 at 12:53 p.m. PDT with information about funding for a second Mobile Launcher.

by Douglas Messier
Managing Editor

There are “emerging concerns about the structural integrity of the Mobile Launcher’s base” from which NASA’s Space Launch System (SLS) and Orion spacecraft will lift off, according to a new government assessment.

The Government Accountability Office (GAO) found that “loads models have indicated low stress margins in critical locations in the Mobile Launcher base. The program attributed this issue to an error in their model.

“The program is currently designing structural reinforcements for the base of the Mobile Launcher and hydraulics pedestals for the launch pad,” the report stated. “Program officials stated this approach could be completed within the program’s existing schedule.”

A source familiar with the project said the flawed model was done by steel contractor RS&H. The company analyzed the modifications required when NASA switched from the Constellation launcher to SLS.

“The margins were negative in some cases, and modifications will be significant, but are going well and there should be no schedule impact,” according to a source, who requested anonymity because he was not authorized to speak to the media.

The problem was discovered by NASA and Jacobs Space Operations Group, which is a contractor on the program. The source said the space agency and Jacobs designed some “clever fixes based on NASA program heritage.”

In March, President Donald Trump signed a spending bill that provides $350 million to NASA for fiscal year 2018 for the construction of a second Mobile Launcher.

The information about the Mobile Launcher’s structural integrity problems was included in GAO’s new report, “NASA: Assessments of Major Projects.” The assessments found that nine of 17 projects surveyed have experienced cost or schedule growth.

The Mobile Launcher is part of NASA’s Exploration Ground Systems (EGS) program, which has experienced cost increases and schedule delays. The total cost overrun depends upon the launch date for the Exploration Mission-1 (EM-1), which will test SLS and an automated version of the Orion spacecraft.

“The new launch readiness date for EM-1 is now December 2019, but NASA has allocated 6 months of schedule reserve to June 2020 for possible manufacturing and production schedule risks. This represents a delay of 13-19 months for EM-1,” the report stated.

“The life-cycle cost estimate for EGS is approximately $3.1 billion to the December 2019 date and $3.2 billion to June 2020, or 11.8 to 14.9 percent above the project’s committed baseline,” the assessment added.

The GAO assessment said EGS’s two major software development efforts—Spaceport Command and Control System (SCCS) and Ground Flight Application Software (GFAS)—are the program’s main schedule drivers.

“GFAS continues to face challenges due to late deliveries from the SLS and Orion programs and delays in SCCS; however, program officials stated they have been heavily focused on resolving SCCS challenges,” the assessment found.

“EGS is restructuring the Systems Engineering and Integration organization, augmenting hardware, and hiring more staff,” the report added. “Program officials noted that a challenge in this restructuring is hiring because NASA is competing for software developers with the local aerospace economy.”

The GAO also found that verification and validation activities have begun for the Mobile Launcher even though ground support equipment and umbilical installation projects are still underway.

“For example, 15 percent of the Mobile Launcher’s umbilicals and launch accessories still have to complete testing,” the report stated. “Program officials previously said this concurrency increases risk because of uncertainties regarding how systems not yet installed may affect the systems already installed.”

The GAO’s assessment of EGS is reproduced below.

NASA: Assessments of Major Projects
Government Accountability Office
May 1, 2018
Full Report

Exploration Ground Systems

The Exploration Ground Systems (EGS) program is modernizing and upgrading infrastructure at the Kennedy Space Center and developing software needed to integrate, process, and launch the Space Launch System (SLS) and Orion Multi-Purpose Crew Vehicle (Orion). The EGS program consists of several major construction and facilities projects including the Mobile Launcher, Crawler Transporter, Vehicle Assembly Building, and launch pad, all of which need to be complete before the first uncrewed exploration mission using the SLS and Orion vehicles.

Project Summary

In December 2017, NASA announced a new schedule and cost estimate for the EGS program, after determining that the November 2018 launch readiness date for Exploration Mission-1 (EM-1) was no longer feasible. NASA is now planning to a launch readiness date of December 2019, with 6 months of schedule reserve to a June 2020 date. The life-cycle cost estimate for EGS is approximately $3.1 billion to the December 2019 date and $3.2 billion to June 2020.

The program’s schedule is currently driven by its two major software development efforts, both of which are undergoing technical challenges. For example, the ground control system is in the process of transitioning to a new contractor and is undergoing organizational changes.

In addition, while the program has made progress with major projects such as the Vehicle Assembly Building and Launch Pad 39B, the Mobile Launcher is continuing to have technical challenges. Fifteen percent of the Mobile Launcher’s accessories and umbilicals still have to complete testing, and there are emerging concerns about the structural integrity of the Mobile Launcher’s base.

Cost and Schedule Status

Credit: GAO

In December 2017, NASA announced a new schedule and cost estimate for the EGS program, after determining that the November 2018 launch readiness date for Exploration Mission-1 (EM-1) was no longer feasible.

In April 2017, we found that the date was likely unachievable for all three human spaceflight programs — EGS, the Space Launch System, and the Orion Multi-Purpose Crew Vehicle — due to technical challenges continuing to cause schedule delays and the programs having little to no schedule reserve to the EM-1 date, meaning they would have to complete all remaining work with little margin for error for unexpected challenges that could arise.

The new launch readiness date for EM-1 is now December 2019, but NASA has allocated 6 months of schedule reserve to June 2020 for possible manufacturing and production schedule risks. This represents a delay of 13-19 months for EM-1. The life-cycle cost estimate for EGS is approximately $3.1 billion to the December 2019 date and $3.2 billion to June 2020, or 11.8 to 14.9 percent above the project’s committed baseline.

Technology

EGS’s two major software development efforts—Spaceport Command and Control System (SCCS), which will operate and monitor ground equipment, and Ground Flight Application Software (GFAS), which will interface with flight systems and ground crews—are the program’s primary schedule drivers, and the program has recently restructured the organization of the SCCS in order to address gaps in systems engineering processes, among other concerns.

EGS’s other major software development effort, GFAS, continues to face challenges due to late deliveries from the SLS and Orion programs and delays in SCCS; however, program officials stated they have been heavily focused on resolving SCCS challenges. According to program officials, increased processing needs combined with unplanned rework led to higher complexity in the SCCS system. This complexity in turn led to a program review of SCCS, which found gaps in the system development process and in SCCS’s organizational structures.

As a result of these issues, EGS is restructuring the Systems Engineering and Integration organization, augmenting hardware, and hiring more staff. Program officials noted that a challenge in this restructuring is hiring because NASA is competing for software developers with the local aerospace economy.

The program is also executing a pre-planned transition that moves SCCS under the same contractor as GFAS and will shift the SCCS development structure to smaller deliverables that can be released more often. A senior NASA official said that EGS’s software development is a top issue leading up to EM-1, and that as a result, the EGS Associate Program Manager was temporarily reassigned to exclusively manage enhancements to the EGS software development effort.

Design

The EGS program has made progress on several projects, including the Vehicle Assembly Building and Launch Pad 39B, but technical challenges continue with the Mobile Launcher. The Mobile Launcher supports the assembly, testing, and servicing of the SLS rocket and provides the platform on which SLS and Orion will launch.

The program has started verification and validation activities for the Mobile Launcher, while ground support equipment and umbilical installation projects are still underway. For example, 15 percent of the Mobile Launcher’s umbilicals and launch accessories still have to complete testing. Program officials previously said this concurrency increases risk because of uncertainties regarding how systems not yet installed may affect the systems already installed.

In November 2017, EGS reported that loads models have indicated low stress margins in critical locations in the Mobile Launcher base. The program attributed this issue to an error in their model. The program is currently designing structural reinforcements for the base of the Mobile Launcher and hydraulics pedestals for the launch pad. Program officials stated this approach could be completed within the program’s existing schedule.

Project Office Comments

In commenting on a draft of this assessment, EGS program officials said the vast majority of EGS development and production content is on track for EM-1 and work is proceeding for the first flight of crew on Exploration Mission-2. In addition, officials said EGS has strengthened its ground software development plans to reflect expected deliveries from other programs. Program officials also provided
technical comments, which were incorporated as appropriate.