GAO: JPL’s SWOT Mission Planning to Launch Ahead of Schedule

SWOT satellite (Credit: NASA JPL)

A Franco-American mission that will conduct a global survey of the Earth’s surface water is moving toward launching a year earlier than planned despite encountering technical challenges and and workforce shortages, according to an assessment by the Government Accountability Office (GAO).

The Surface Water and Ocean Topography (SWOT) satellite “will use its wide-swath radar altimetry technology to take repeated high-resolution measurements of the world’s oceans and freshwater bodies to develop a global survey,” the report stated.

“This survey will make it possible to estimate water discharge into rivers more accurately, and help improve flood prediction. It will also provide global measurements of ocean surface topography and variations in ocean currents, which will help improve weather and climate predictions,” the assessment added.

SWOT is a joint project of NASA and the French space agency, CNES. The Canadian Space Agency and the UK Space Agency are also participating in the project.

The GAO found the project is keeping within its cost baseline and still plans to launch aboard a Falcon 9 in April 2021, which is a year earlier than planned.

Engineers have encountered several technical problems, including with the satellite’s main instrument —  the Ka-Band Radar Interferometer (KaRIn).

“An engineering model of the KaRIn high voltage power supply was damaged during testing due to three electrical arcing events that were caused by manufacturing and handling of parts, and weaknesses in the packaging design,” the report stated.

“In addition, the project augmented the main beams that connect the instrument antennas to the spacecraft, which resulted in delays to releasing design drawings,” the assessment added. “The project discovered signal interference off the main beams that could distort KaRIn’s science measurements.”

There also have been workforce challenges.

“Further, in January 2018, the NASA Office of Inspector General found that the SWOT project, which is managed by the Jet Propulsion Laboratory, experienced workforce shortages in key fields to design and develop its instruments,” the report stated. “The report stated that the staffing problems were driven by conflicting priorities among several other Jet Propulsion Laboratory projects, including Mars 2020, that also needed those skills.”

The GAO’s assessment of the SWOT mission is below.

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

Surface Water and Ocean Topography

The Surface Water and Ocean Topography (SWOT) mission will use its wide-swath radar altimetry technology to take repeated high-resolution measurements of the world’s oceans and freshwater bodies to develop a global survey. This survey will make it possible to estimate water discharge into rivers more accurately, and help improve flood prediction. It will also provide global measurements of ocean surface topography and variations in ocean currents, which will help improve weather and climate predictions. SWOT is a joint project between NASA and the French Space Agency—the Centre National d’Etudes Spatiales (CNES).

Project Information

NASA Lead Center: Jet Propulsion Laboratory
International Partners: Centre National d’Etudes Spatiales (France), Canadian Space Agency (Canada), United Kingdom Space Agency (United Kingdom)
Launch Location: Vandenberg Air Force Base, CA
Launch Vehicle: Falcon 9
Mission Duration: 3 years
Requirement Derived from: 2007 Earth Science Decadal survey
Budget Portfolio: Science, Earth Science

Project Summary

The SWOT project continues to operate within its cost baseline and plans to launch in April 2021, a year earlier than its committed schedule baseline, despite encountering technical issues with its main instrument — the Ka-Band Radar Interferometer (KaRIn). An engineering model of the KaRIn high voltage power supply was damaged during testing due to three electrical arcing events that were caused by manufacturing and handling of parts, and weaknesses in the packaging design.

In addition, the project augmented the main beams that connect the instrument antennas to the spacecraft, which resulted in delays to releasing design drawings. The project discovered signal interference off the main beams that could distort KaRIn’s science measurements. Project officials said they planned to release about 90 percent of design drawings at the planned February 2018 critical design review, which is a best practice.

Cost and Schedule Status

Credit: GAO

The SWOT project continues to operate within its cost baseline and plans to launch in April 2021, a year earlier than its committed schedule baseline. The project is holding schedule reserves consistent with the level required by Jet Propulsion Laboratory policy, but did not meet cost reserve requirements in fiscal year 2017 due to costs associated with risk reduction activities and to stay on schedule. For example, project officials said they used cost reserves to build higher-fidelity engineering models and to secure a higher than planned workforce to execute fiscal year 2017 tasks.

However, the project was able to reconstitute some of its cost reserves due to lower than-expected launch vehicle costs and is meeting cost reserve requirements for fiscal year 2018 as of January 2018. The project is progressing toward its critical design review scheduled for February 2018.

Credit: GAO

Technology and Design

The project’s primary instrument—the Ka-Band Radar Interferometer (KaRIn)—continues to be the most complicated development effort and has experienced technical issues that have had cost and schedule implications. During testing, an engineering model of the KaRIn high voltage power supply (HVPS) was damaged due to three electrical arcing events that were caused by manufacturing and handling of parts as well as weaknesses in the packaging design.

To mitigate these events, the project repaired the electrical board within the engineering model with temporary fixes to support upcoming testing and built a second electrical board with enhanced handling procedures for a key thermal vacuum test in February 2018. As a result, HVPS development is driving the project’s schedule.

To maintain its current schedule, the project is building the HVPS flight model in parallel to its ongoing testing of the engineering model. The project determined this approach was less risky than delaying flight model development until engineering model testing is complete. The project is tracking a risk, however, that development of the flight model concurrently may cause late rework.

In addition, the project augmented the main beams that connect the instrument antennas to the spacecraft, which resulted in delays to releasing design drawings. The project discovered signal interference off the main beams that could distort KaRIn’s science measurements. To mitigate this risk, the project added a reflective plate to the main beam to minimize signal distortion and successfully held a mechanical critical design review with the modified main beam design. As a result, however, the project is 3 months behind schedule in releasing drawings for the modified design and is working with the Jet Propulsion Laboratory to secure additional staff to accelerate drawing production.

As of January 2018, SWOT released 87 percent of its expected drawings and project officials said they plan to release about 90 percent of design drawings at critical design review. Best practices show that releasing at least 90 percent of design drawings by this review can decrease a project’s risk of cost growth and schedule delays.

Other Issues to Be Monitored

After the project experienced challenges with one of the tools—AirSWOT—that it plans to use to help understand the data returned from the KaRIn instrument once SWOT is in orbit, the project selected two additional methods to augment ocean measurements. The project determined that the performance of AirSWOT, which is an airborne sensor, was likely to be insufficient and that heavy wave activity when collecting ocean data was the root cause of measurement abnormalities.

The project selected an airborne laser-based remote sensor along with a network of underwater gliders to augment the measurements from in-orbit satellites that were planned with AirSWOT. This approach successfully passed a technical peer review in December 2017 and the project plans to complete additional experiments using the selected approach to inform its calibration and validation plan.

Project Office Comments

In commenting on a draft of this assessment, project officials stated that SWOT is a challenging mission
making a first of a kind measurement of global surface water. Officials also stated the project has been advancing the heritage systems development allowing the project to focus on the challenging KaRIn development. The project is completing thorough testing of engineering models along with a series of technical reviews in preparation for the flight model development. The project’s focus remains on systematically rectifying technical issues while devising workarounds to maintain the overall milestones. SWOT officials also provided technical comments, which were incorporated as appropriate.