Measuring NASA—€™s space

January 2011 » Web Exclusive » PROJECT CASE STUDY
At the NASA Langley Research Center in Virginia, a team of positioning specialists uses 3D scanning to support operations, facilities management, and aerospace research.
John Stenmark, L.S.

For more than 90 years, the NASA Langley Research Center in Hampton, Va., has been at the forefront of America’s history of aviation and spaceflight. Founded in 1917, NASA Langley (LaRC) is the country’s oldest civilian facility for aeronautical and aerospace research. The base served as the initial home to Project Mercury, America’s first manned spaceflight program, and has participated in testing or development of virtually every type of aircraft flown by the U.S. military. With more than 290 buildings on 788 acres, LaRC is home to wind tunnels, test structures, and laboratories that conduct research on military and civilian air- and spacecraft. Because of LaRC’s size and variety of functions, the base facilities are constantly evolving. In order to support operations and facilities management, LaRC needs up-to-date spatial information on its buildings, structures, and equipment.

Much of LaRC’s spatial information is developed and managed by the Langley Center Operations Directorate’s (COD) Geographic Information Systems (GIS) team, led by Brad Ball. This group of measurement specialists and GIS professionals provide positioning and related services to Langley’s scientists, engineers, and facilities managers. Combining a variety of measurement technologies with visualization, data management, and GIS, the Langley team is opening new applications for positioning systems. One of the team’s most powerful tools for the future is expected to be 3D scanning. Capable of collecting thousands of individual 3D points in one second, 3D scanners have proven to be a fast, accurate way to collect detailed spatial information for LaRC’s broad variety of needs.

Scanning for building renovation
LaRC Building 1230 is one of the older structures on the base. Throughout the years, the building has undergone numerous modifications to support different uses and projects. But the building’s drawings have not kept pace with the changes. As a result, engineers and construction teams are forced to work with inaccurate information when managing and operating the facility. In preparation for an extensive remodel, all of the interior partitions were removed from one wing of the building. With the structural and mechanical features exposed, the LaRC GIS team used a Trimble GX 3D Scanner to scan the interior and exterior of the building. The information developed by the scanner will be used to develop a building information model (BIM) for the facility and to check existing plans and measurements.

Using true-color, high-density scanning, the crew scanned the entire building in less than a week. “We scanned the interior and exterior of the building and composited the scans together,” said Jason Hall, a GIS analyst on the Langley team. “We linked the interior scans by carrying control through stairwells.” They tied scans together using a combination of spherical and flat targets, which were placed to be intervisible from multiple instrument locations. The team used the Trimble GX survey-style workflow to connect the instrument stations in the field, eliminating the office work often needed to register the multiple scans together. Hall used Trimble PointScape software to manage the density and precision of the measurements.

It required scans from more than 15 locations to collect a complete picture of the building wing, which is approximately 74,000 square feet. At each location, the crew used the Trimble GX video camera to capture photographic images of the scene. The images can be “draped” over the point cloud to produce a 3D photorealistic image of the building, right down to individual bricks, bolts, and fittings. While still in the field, Hall merged the individual scans into a single point cloud for the entire wing.

Once the field work was complete, the LaRC team used Trimble RealWorks software to process and check the data. Then they extracted subsets and cross-sections that were sent to Autodesk Revit and other systems for use in developing design and construction plans. Langley increasingly uses BIM for its facilities management, and Ball said that the 3D scanner plays an important role in validating the building models. The scanner has become an important part of LaRC’s facilities management toolbox.

There is an extensive GIS at Langley, and a single geodetic coordinate system has been established for the entire base. Roads, utilities, and other structures are tied to the LaRC GIS, which includes base boundaries and surrounding areas. Because the scanner’s workflow makes it easy to connect scanned data to the LaRC coordinate system, it is straightforward to determine the physical relationship between a BIM component (interior or exterior) and its surrounding features. For the work at Building 1230, the team used real-time kinematic GPS (RTK) to establish exterior setup points for the scanner; the points were tied directly to the LaRC geodetic coordinate system.

Scanning Langley’s wind tunnels
The LaRC GIS team uses 3D scanning technology to support scientific research as well as facilities management. To assist with a recent project, the team used the Trimble GX to scan the test section in a Langley wind tunnel. (The test section is the portion of a wind tunnel that contains models and instrumentation to collect test data.) In this tunnel, the test section is approximately 60 feet long and 25 feet high. There is an overhead crane above the tunnel’s test section.

For most tests in the wind tunnel, models are placed into the tunnel’s air stream on a “sting,” which extends through the floor and into the tunnel’s test section. As part of a proposed new capability, NASA researchers wanted to evaluate suspending a model from the crane rails instead of using the sting. For the test to produce the necessary data, the researchers needed precise information about the relationship between the crane rails and the bottom and throat of the tunnel. Using the Trimble GX scanner, the team took three scans and collected roughly 3 million points in less than a day. After a processing and quality check using Trimble RealWorks, the point cloud was exported to DXF and AutoCAD formats. The researchers used the point cloud information to determine dimensions in the wind tunnel to a precision of 0.01 feet.

The LaRC GIS team also used the scanning system on a pair of older wind tunnels. The Langley Full-Scale Wind Tunnel, which was built in 1930, has a test section that is 30 feet high, 60 feet wide, and 56 feet long. After a lifetime that spanned tests of propeller-driven fighters through supersonic transports, the tunnel was decommissioned in 2009. The LaRC GIS team used the 3D scanner to capture a point cloud and images of the tunnel and its surrounding structure and equipment. The tunnel is to be demolished, and the scanned data will be used to develop detailed information about the historic device.

A second wind tunnel — the 8-foot Transonic Pressure Tunnel — also is slated for removal, and there are plans for its test section to be transferred to the Smithsonian Institution. Using the Trimble GX, the GIS team scanned the belly and sides of the test section. The information will be used to design a cradle to support the test section for storage and display.

The Ares launch abort system
In October 2009, NASA conducted the first flight test of its Ares 1-X rocket. The flight’s main objective was to test the new configuration of a solid rocket first stage with a liquid-fueled second stage. In order to provide a realistic test, the Aries 1-X needed to carry a payload that matched the manned crew capsule it will launch in the future. As one of their roles in the project, LaRC teams built a simulated upper stage, crew module, and launch abort tower for the rocket. While they were simple mock-ups, the elements had to be dimensionally correct to provide accurate data during the test.

The components of the upper stage mock-up were built at Langley and assembled in a hangar on the base. While each component had been measured individually, the LaRC fabrication team needed to confirm that the fully assembled upper stage was correctly aligned and met the design dimensions. With the spacecraft assembled in its vertical ”stack” or launch-ready configuration, Hall used the Trimble GX to collect and register four scans of the assembly, which was roughly 12 feet in diameter and 45 feet tall. He then used Trimble RealWorks to join the scans and create a 3D model of the assembly. The scans confirmed the alignment and provided a baseline model of the stack before it was shipped to Kennedy Space Center (KSC) in Florida. When the assembly arrived at KSC, teams there could use the LaRC baseline data to determine if any damage had occurred in transit.

In addition to scanning large objects and spaces with the Trimble GX, the LaRC team used a Trimble CX Scanner in an evaluation project in smaller, more congested areas. John Meyer, an engineer on the GIS team, said that the Trimble CX is well-suited for many applications at Langley, where measurement tasks often include surveys of rooms crammed with pipes, wiring, and equipment. “The scanner gives us a very accurate picture of complex situations,” Meyer said. “It’s especially useful in industrial situations where you have to document or plan upgrades or retrofits.” Because of differences in measurement technologies, there is no “one size fits all” scanner, and Ball sees the two scanners as complementary instruments that will broaden the LaRC GIS team’s effectiveness.

Team players
The LaRC GIS team uses its scanning and GIS technologies to help drive NASA as a whole, and frequently travels to other NASA facilities to share their expertise. As part of its role in facilities management, the LaRC team is active in space optimization and allocation planning based on georeferenced spatial information. They developed an approach to create plans for a facility move that will result in significant savings in time and costs. In 2009 the team received a Special Achievement in GIS award from Esri in recognition of its innovation and leadership in GIS and spatial data.

Through its creative use of scanning technology, the NASA Langley GIS team has developed the reputation of making accurate measurements of objects and facilities that otherwise would be very difficult to measure. “With this equipment, we deliver information that no one else can provide,” Meyer said. “The fact that we can supply measurements to a variety of disciplines is very important.” The technology already has demonstrated that it delivers significant time and cost savings on maintenance and remodel projects. Ball believes that 3D scanning technology is an exciting new tool for facilities management. In the hands of NASA’s capable, creative people, it also solves scientific and engineering problems quickly and efficiently. Once considered a luxury, 3D scanning is rapidly being included as a cornerstone of LaRC projects. From that foundation, innovation takes flight.

The LaRC GIS team used a Trimble GX scanner to scan the 60-foot-long by 25-foot-high test section in a Langley wind tunnel.
The test section of a second wind tunnel — the 8-foot Transonic Pressure Tunnel —is slated to be transferred to the Smithsonian Institution. The GIS team scanned the belly and sides of the test section to provide information for design of a cradle to support the test section for storage and display.
LaRC teams built a simulated upper stage, crew module, and launch abort tower for the first flight test of NASA’s Ares 1-X rocket. With the spacecraft assembled in its vertical ”stack” or launch-ready configuration, GIS Analyst Jason Hall used the Trimble GX to collect and register four scans of the assembly, which was roughly 12 feet in diameter and 45 feet tall.
Trimble RealWorks was used to join four scans and create a 3D model of the Ares 1-X upper stage, crew module, and launch abort tower. The scans provided a baseline model of the stack before it was shipped to Kennedy Space Center in Florida.

John Stenmark, L.S., is a writer and consultant working in the AEC and technical industries. He has more than 20 years experience in applying advanced technology to surveying and related disciplines.

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