If you have young children of a certain age, especially boys, you know that they are fascinated by very large machines, such as trucks, trains and construction equipment. Well, I may be a middle-aged adult, but I’m still captivated by really big machines.
Recently, I had the chance to interview Jean-Gillesthe NASA operations manager in charge of perhaps the biggest machine on the planet and certainly the biggest material handling machine, NASA Crawler-Transporter 2. Weighing 6.65 million pounds, with a payload capacity of 18 million pounds, it is billed as the largest tracked vehicle on Earth. Think of it as the Argentinosaurus of machines, an AGV like no other. “You have no idea until you stand next to its size,” says Giles, whose official title is Crawler Element Operations Manager, Exploration Ground Systems, NASA’s John F. Kennedy Space Center. It’s a fitting headline for a guy who oversees such a big machine, something he’s been doing for ten years. You can Click here to view a video link from Business Insider.
If NASA sticks to an August 15 launch schedule, the robot will begin a midnight journey around August 9 from the Crawler yard, where the vehicle lives, to the launch pad. It’s only 4.2 miles – I’ll explain the details in a moment – but it takes between 8 and 12 hours with the vehicle going at around 1 mile per hour. Fuel efficiency was not a priority when designing the vehicle: the Crawler will burn around 530 gallons of diesel while driving. Given the price of diesel at the pump, you can do the math. Driving the Thing isn’t without stress considering the size of the payload and the precision required to position it within a quarter of an inch at the launch pad. Giles says NASA changes operators every 45 to 60 minutes.
The crawler has a long history. Like the B-52 bomber, which first entered service in 1952 and is still in service, the Crawler has been delivering payloads for NASA since the 1960s. “I like to tell people that even though we have completely rebuilt the launch pad and the Vehicle Assembly Building (VAB), where we build the spacecraft, the thing that brings us to the platform is 57-year-old equipment that is still working today,” said said Giles.
Even more impressive, the original design by the Marion Power Shovel Company with components from Rockwell International was made on paper with state-of-the-art tools around 1964: pencils, T-squares and slide rules. Two crawlers were originally built to move the Apollo Saturn V moon rocket at a cost of $16 million each. When they were assembled at the Kennedy Space Center site in 1965 – they were too big to transport – they were the largest self-propelled ground vehicles in the world. The first mission took place on August 26, 1967, when a robot was used to transport a VAB spacecraft to a launch pad for an Apollo 4 mission.
The Apollo program called for a payload of 12 million pounds. But when the shuttle program ended, NASA realized that the next launcher “was going to be bigger than anything we’ve ever done. We were given a target weight of 18 million pounds, which is 50% more than what it was designed for,” Giles said. To achieve this, NASA installed a new braking system, new gearboxes and additional welded steel. The project lasted two and a half years. “When scientists from the Ames Research Center came to evaluate the vehicle, they realized that the original designers had given us several safety factors, which allowed us to modify the vehicle,” Grimes said.
Today, the caterpillars are maintained and operated by the Jacobs Engineering Group, which also trains and employs drivers. And not just anyone can be a driver. For starts, a pilot must be an engineer from an accredited institution. Before they can drive, drivers must learn to operate, troubleshoot and maintain hydraulic, mechanical and electrical systems and spend time in the control room. If they pass, they are eligible to go to driving school and learn how to maneuver the vehicle through straights, curves, docking and, most importantly, the 5 degree incline that leads to the ramp launch, the most painful. part of the trip. “It takes a good two years to become a certified pilot,” Giles said.
Back to the trip. As we said, it starts in the middle of the night a good two or three days before launch. From the track yard, the vehicle travels to the VAB, a 550-foot-tall building where spacecraft are assembled, to pick up its load. The spacecraft is assembled above its mobile launch pad, so the robot rolls underneath. When it does, the team begins the process of lifting the 18-inch launch pad to transfer it to the robot. It takes about half an hour, with about 20 people posted around the perimeter to watch for danger.
Once the mobile launch pad and vehicle are in place, the crawler begins its arduous journey to the launch pad. By the time he reaches his destination, the hours have passed, the drivers are exhausted, everyone is tense, and now the most stressful part of the trip begins. “When we get to the bottom of the launch pad, we have to go up the incline,” Giles said. “It’s got to be precise, or we’ve got to get it back down the slope and start over.” There are gravity and leveling issues. The motors must be running at peak performance and the driver is guided by a laser to line up perfectly where they need to be on the pad. In the old days, before lasers, they used a rope.
Once the vehicle is in place, things need to be connected and disconnected so the rocket can be removed from the platform. Once all of this is done, the team receives the signal that they can lower the spacecraft into place. It takes at least half an hour, followed by several connections and disconnections before the robot descends the hill with the empty mobile launch pad as its payload.
The crawler at the launch pad.
But the team is not yet formed. The crawler will stay outside the pad door for the next two to three days to make sure everything is going well. From there it waits in a mobile service structure midway between the launch pad and the track yard until the launch takes place. Finally, once the vehicle is in the air, the mobile launch platform is brought back to the VAB and the crawler to the tank farm. Basically it’s about 4 days to do a round trip of about 10 miles.
After 10 years on the team, I asked Giles what he has left the most. He said it was the fact that they could be so precise with something so huge. “Our tolerances are tight,” he said. “We have to be within a quarter inch of where we’re supposed to be, or we have to spend half an hour coming back down the hill and trying again,” he said. “Fortunately, we usually succeed.”
He added: “When you’re next to this beast when it’s running, it’s constant noise, vibration, dust and heat. If you are a mechanic or an engineer, you are at home. It’s great equipment. »
About the Author
Bob Trebilcock Bob Trebilcock, Managing Editor, has covered material handling, technology, logistics and supply chain topics for nearly 30 years. In addition to Supply Chain Management Review, he is also editor of Modern Materials Handling. A graduate of Bowling Green State University, Trebilcock lives in Keene, NH. He can be reached at 603-357-0484.