THE CHALLENGE
Upgrading one-of-a-kind undercarriages on the world’s largest self-powered land vehicles
The U.S. National Aeronautics Space Administration (NASA) needed to upgrade one of the twin Crawler Transporters, the largest self-powered land vehicles on Earth, to carry a new generation of bigger, more powerful rockets and spacecraft to and from the launch pad at Kennedy Space Center (KSC) in Florida. This upgrade of the Crawler-Transporter 2 (CT-2) included improving the four massive undercarriages for total loads surpassing 21 million pounds, better lubrication and longer operational life.
The complex retrofit upgrade of the CT-2 undercarriages involved the custom manufacturing of more than 1,300 improved components, removing the old parts, on-site line boring of 88 lower roller bores and faces to tight tolerances specified by the NASA Ames Research Center, and installation of the upgraded custom assemblies.
The project held significant risk in terms of what the disassembly process would reveal—the undercarriages of these unique machines, based on 1960’s Marion power shovels, hadn’t been taken taken apart since the crawlers were built 50 years ago.
NASA needed a contractor with the right expertise and capabilities for this incredibly specialized job.
IMPACT ON NASA OPERATIONS
CT-2 technology needed improvements to support the future of space exploration
The undercarriage upgrade of CT-2 was space-mission critical for keeping up with the evolution of spacecraft and NASA programs. The project left zero room for error in eliminating the possibility of unplanned crawler downtime that could jeopardize launch schedules, budgets, and the power supply and function of critical systems that ultimately ensure astronaut safety.
L&H won the contract for the CT-2 undercarriage retrofit upgrade based on our abilities not only to custom-manufacture components meeting NASA’s tight tolerance requirements but also to install those components in the field, dependent on precise field-machining capabilities.
THE SOLUTION
State-of-the-art machining and rigorous quality assurance from start to finish
The NASA Crawler-Transporter 2 has four undercarriages with 11 sets of lower roller bores on two sides, for a total of 88. The entire lower roller assembly installed into each bore includes a shaft, bushing, outer boss extension, and pins.
L&H took a test-and-prove approach to estimating the costs of the two-year project, building a mockup and testing machining times to anticipate challenges. These preliminary steps also enabled L&H to recommend design improvements for better undercarriage performance.
During boring and installation of the roller assemblies, L&H stationed a quality assurance specialist on-site at KSC to ensure compliance with NASA’s tight tolerance specifications of +/- 0.0002”. Because of our advanced machining capabilities, we were also able to machine the roller assembly shafts to a finer surface finish than required.
L&H upgraded the first two undercarriages, tested and proved the assemblies, then implemented process improvements that increased the reliability, safety and speed of upgrading the second set of undercarriages. This enabled us to beat the projected schedule safely while delivering a top-quality product.
“Working with L&H has been a very positive experience. Everything we’ve seen is very much a can-do type attitude, and the quality of the work has been top-notch. [Of the companies that bid on the project] L&H was the only one that had the ability to or was proposing to do all of the work in-house, in other words all of the manufacturing as well as the installation.”
—Gary French, Mechanical Engineer, NASA – Ames Research Center
THE RESULTS
L&H successfully updated the CT-2 undercarriages to carry next-generation spacecraft
In the ultimate test of our precision manufacturing and field machining capabilities, L&H completed the retrofit upgrade of the massive NASACrawler-Transporter 2 undercarriages ahead of schedule, within budget, and with quality surpassing the original project specifications, successfully increasing the payload of the world’s largest self-powered land transport vehicle by 6 million pounds.
Additionally, our success on this project led to a second project for the CT-2 upgrade, rebuilding all of the machine’s propel transmissions, another intricate, high-precision upgrade for this one-of-a-kind machine.
“L&H comes through. They deliver. Their quality, their dedication to getting the job done correctly the first time is there.”
— Dave Cunneen, Project Manager – CT-2 Upgrade, QinetiQ – North America