Crawler Transporter 2 has been upgraded to support the additional weight of the SLS rocket. Photo credit: Mike Howard / SpaceFlight Insider
CAPE CANAVERAL, Fla — Officials from NASA’s Kennedy Space Center rolled out the newly renovated Crawler Transporter 2 (CT-2) on Monday, Feb. 23, 2015. The 6.5-million-pound CT-2 will carry a 10.3-million-pound mobile launcher with the 4.4-million-pound Space Launch System (SLS) booster (without liquid propellants), resulting in a massive, 21.2-million-pound vehicle lumbering along to the launch pad at Launch Complex 39B.
For more than two years, NASA’s CT-2 has been undergoing a major overhal in the Kennedy Space Center’s Vehicle Assembly Building (VAB). Recent work has included preparations to install upgraded components that will enable the crawler to carry the greater loads anticipated with the agency’s new rocket designed to take astronauts beyond low-Earth orbit (LEO) for the first time since the early 1970s.
“We removed and replaced the roller-bearing assemblies,” said Mary Hanna, CT project manager in the Vehicle Integration and Launch Branch of GSDO. “These upgrades are designed to make sure the crawler will support us for another 50 years,” she said. “Many of the older parts were wearing out from years of use.”
The renovations were supported by NASA’s Test and Operations Support Contract by Jacobs Technology Inc., NASA’s Engineering Support Contract by QinetiQ Inc., both at Kennedy, as well as Mammoet Inc. of Houston, and L&H Industrial Inc. of Gillette, Wyo.
“L&H is producing the rollers, shaft assemblies, sleeves and other hardware needed,” Hanna said. “Altogether, that amounted to about a half-million pounds of steel being delivered here at Kennedy.”
Technicians from Jacobs performed the work of removing the crawler treads prior to Mammoet jacking and cribbing the corners. L&H then removed the old roller bearing assemblies and inspected the structure and integrity of openings.
When asked how she felt about working on a project that was such a big part of both space history and future missions, Hanna said, “I’ve been working on the crawler for three years now. It has a great deal of history, from Saturn V to Skylab to Shuttle. It was a very moving experience just to be apart of the final shuttle missions and now to prepare the transporter for the future. It’s mind-boggling to be a part of this.”
“There weren’t many changes needed, but the new assemblies will help the crawler carry the heavier load,” Hanna said. “The newer system will also be better lubricated and that should provide a longer operational life.”
NASA has used the crawler since the 60s during the Apollo Program where the massive Saturn V booster would trundle atop the machines out to Launch Complex 39 where the rocket was used to send crews to the Moon. After decades of use, the crawlers have encountered their fair share of wear.
“When you have that much metal-on-metal carrying such huge loads, there is a tremendous amount of heat and friction,” Hanna said. “That creates much of the wear and tear that we see on the crawlers. The improvements will keep the crawler running for a long time.”
Future modifications to extend the lifetime of CT-2′s systems include upgrades to the jacking, equalization and leveling cylinders. This will increase their load-carrying capacity and reliability.
Other work completed includes replacement of electronics, cables, tubing, hydraulic components, as well as cleaning of fuel tanks and hydraulic systems.
If everything goes according to plan, the crawler-transporters will deliver the first SLS to LC-39B in 2018, where it will conduct its first test flight. During this mission, dubbed Exploration Mission 1 or “EM-1,” SLS will ferry NASA’s new crew-rated Orion spacecraft on a journey around the Moon. This is in preparation for missions to an asteroid and, one day, the planet Mars.
Video courtesy of Bill Jelen/Spaceflight Insider
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La  fête les 50 ans des ''crawler-transporters'', deux imposants véhicules à chenilles conçus dans les années 60 pour le  d'exploration de la . Le rôle des ''crawlers'' est de déplacer le lanceur du bâtiment d'assemblage jusqu'au pas de tir, qu'il met 6 heures à atteindre grâce à 6 moteurs diesels de  consommant  par heure.

Depuis, ces engins de  ont été modifiés pour accueillir les navettes spatiales et sont en cours d'amélioration pour assurer leur compatibilité avec le futur ''Space Launch System'' (SLS), actuellement en développement. Pour célébrer cet anniversaire, la NASA a proposé aux journalistes de suivre le ''crawler'' n°2 lors d'une démonstration.

, a déclaré John Giles, responsable de l'engin. , a-t-il ajouté.


Fichier:Apollo Saturn 500F and VAB.jpg|Un crawler transportant le lanceur Saturn V lors d'essais en juin 1966.
Fichier:STS-114 rollout.jpg|La navette ''Discovery'' acheminée jusqu'au pas de tir en juin 2005.