Meet the heavy vehicle drivers helping take a rocket to the moon


At Big Rigs we’ve always been humbled by the number of overseas readers we have and their generous feedback, but we reckon this approach just about takes the cake in our 30th anniversary year.

Impressed by Aussie truckies’ many transport feats highlighted in Big Rigs, America’s space agency, the National Aeronautics and Space Administration (NASA), reached out to share an exclusive chat with the drivers of its Crawler-Transporter 2, the Earth’s largest tracked vehicle.

The 3016-tonne behemoth has been carrying rockets to the launch pad at John F. Kennedy Space Centre in Florida for the last 57 years, including Apollo 11 that landed the first men on the moon in 1969.

Next month, the Crawler is tasked with another historical mission: transporting the 6,713,167kg Space Launch System Rocket and Orion spacecraft – cradled in its mobile launcher – to the launch pad for fuelling and flight into the cosmos as part of the Artemis program, of which Australia is now considered an important partner.

The first stage, Artemis 1, will not carry astronauts but is seen as a crucial precursor to deep space crewed missions slated for coming years, which will also see the first woman walk on the moon by mid-decade.

To mark the milestone March launch – a ‘wet dress rehearsal’ is scheduled for late February – Big Rigs sat down with Crawler drivers Sam Dove, 63, and Breanne Rohloff, 24, who work for NASA contractor Jacobs, to find out more.

What’s it like to be a NASA Crawler driver?

Sam: It dominates whatever’s around it. You can feel the massive machine as it comes by, it shakes the ground a little bit… it would just amaze you; the size and the complexity of the world’s biggest tracked-vehicle. Think of something that’s moving very slow – around 1.2-1.3km/h – moving this massive rocket down the road. It’s fun to get up every day and come out and work on the Crawler.

Breanne: Mind-blowing. When I looked up at the Crawler moving for the first time I was in awe, just taking in the size and power it has. Every day is different on the Crawler, and there’s a lot of parts and pieces to learn and become proficient in.

Crawler driver Breanne Rohloff, 24.

How’d you land in jobs that only a few humans in the universe occupy?

Breanne: This is my first full time job out of college. I did an internship at the space centre while in college and looked to come back out here after graduating.

Sam: I grew up in West Virginia as a farm boy, served four years in the U.S. Air Force and then went to college. After, I was fortunate enough to get a job at the Kennedy Space Centre in 1987. I spent the first 10 years in design engineering, and then moved to operations where I became a Crawler engineer and driver. So, it wasn’t just something that I stepped off the street and did. It took time, training, education, and experience. It’s really not something comparable to what a lot of folks see.

Breanne: You must have an engineering degree and complete an extensive on-the-job training program. Kennedy currently has eight certified drivers and one more in training.

How many people does it take to operate?

Breanne: The team is about 30 engineers and technicians that huddle up a few hours before a roll to the launch pad to review the operation, talk safety, and discuss who’s in charge of each task. We switch positions through-out the roll to keep fresh eyes on the systems, we all work together to execute a successful rollout.

Sam: There are at least 10 engineers and 20 technicians on or around the Crawler at any time. You’ll have an engineer that is the test conductor, an engineer operating the jacking equalisation and leveling system, and two engineers as the primary and secondary drivers. Technicians will staff the engine rooms, the pump room and roving hydraulics positions. There will also be four to five technicians on the ground to help with guidance and to watch over systems/equipment. It’s a specialised team for the world’s largest tracked-vehicle.

Experienced driver Sam Dove, 63, looks forward to coming to work every day.

How does the team start the rocket mover?

Sam: The first thing that lets you know we’re starting up is the use of compressed air to start the ALCO engines. Then, the second set of engines start. After that, power transfer occurs. Then the hydraulics and support systems are started. It really has a sound all of its own. You need to be attuned to what the equipment sounds like and if it’s not running right you can almost immediately tell when you need to start looking at something.

Breanne: Hauling a billion-dollar spacecraft to the launch pad starts just like any other vehicle that moves – with start-up sequences in the control room, power transfer, the push of a button, and the twist of a knob in the cab.

The beast only goes 1.5km/h. Is that speed monotonous?

Sam: Oh, no. Boredom is not something that you have on the Crawler. You’re watching where you’re going, where you’ve been, where you’re at, the speed, what your steering angle is and many other parameters. You must be aware all of the time because if the Crawler catches you not paying attention, it will remind you.

Breanne: We may crawl slow but that doesn’t equal an easy drive. Driving the Crawler is a bit like steering a large ship, and when the rocket is onboard, it will be like steering a large ship with a skyscraper on top. You’re constantly making small steering corrections, even when you’re moving straight.

Sam: Since the vehicle is only designed to make six-degree turns, drivers need to start turning well in advance when approaching curves on the Crawler way – the 6.7km river-rock ‘road’ the Crawler travels on to the launch pad.

Breanne: Being a certified Crawler driver is not just learning how to drive the machine. You must also under- stand and be able to operate the Crawler’s other major subsystems. After one to two years of on-the-job training, we drivers-in-training will be on our way to becoming a certified Crawler driver.

What’s surprising about a rollout of the rocket to the launch pad?

Sam: The amount of planning and coordination that goes into each operation.

Breanne: We’re also constantly on the lookout for wild animals: bobcats, alligators, turtles, snakes, wild hogs, coyotes, etc. You just sit there thinking, please don’t move into the Crawler way. If they do, you need to stop the Crawler and get the wildlife out of the way.

Sam: There was a 12-foot alligator that was under one of the trucks. We had to call the wildlife officer to come and pull that gator out. You could compare the wildlife officer to Steve Irwin, he just reached under the vehicle, grabbed that gator by the tail, pulled it out, trussed it up and released it at a remote location on the space centre.

Breanne: And then there is the tale of the tortoise and the Crawler – less well known than The Tortoise and the Hare fable.

Sam: We have had numerous encounters with turtles, tortoises from time to time.

Breanne and Sam may crawl slow, but it’s never an easy drive.

The tortoise and the Crawler were both heading up the ramp, side by side?

Sam: We have had turtles walk beside of us and cut in front of us, behind us, etc. The Crawler usually vibrates the ground and scares the turtle out of the ground. They don’t stay close very long. They usually get moved to safety by one of the crew.

The whole ride down the Crawler way is leading up to the most crucial and technical moment when the Crawler approaches the launch site.

The Crawler transits up the pad slope (ramp) and then places the rocket, with its launcher, precisely onto the launch mounts.

Breanne: And that’s when things get exciting and everyone becomes even more focused.

Sam: By far the most stressful part of any roll-out is going up the pad slope. All the systems have to work, the team has to be on top of its game for the operation to be successful.

Breanne: The first time I was on the Crawler when we pulled up the pad slope I was just observing. But seeing other engineers, the more experienced ones drive up, I felt nervous just being in there with them. You must be very precise on the slope and on the pad surface. There is very little margin for error.

Sam: When we go up the slope, it’s all hands-on deck. Everybody is on station in an assigned area. All the engines have to be running at their peak performance. There’ll be technicians standing by watching every gauge and every fluid level as we’re rolling. If we were to go up that ramp and then lose power for some reason, we would have to stop and hold on the pad slope. Not a good day at all.

The Crawler is on a 5-degree slope, but the rocket needs to stay completely level, so the jacking, equalisation, and leveling system kicks into high gear. By that time, the Crawler is going even slower than normal?

Sam: Slope speed is .56km/h, or less. Once we get on top of the pad, the speed is .39km/h, or less.  As we get closer to the mounts, we jack up to the proper height to go over the mounts and stay aligned to the docking laser. Once we have stopped and everything is leveled, we will set the whole Mobile Launcher/SLS/Orion stack on the pad launch mounts, usually within .3 cm.

Do you have any Crawler team traditions after a successful rocket roll-out?

Sam:  At one time, after hard down, we broke out chips and salsa. Unfortunately, now, with Covid protocols, and our assigned tasks, we most likely will not be able to have the post-roll-out snack.

Breanne: That’s okay, I’m not a big fan of salsa!

Breanne, you’re on the ground floor of NASA’s new Artemis generation yet Sam was the Space Shuttle generation… what is the take-away?

Breanne: NASA’s Artemis missions are only possible because of Sam and the thousands of others who put in the work and launched 135 shuttle missions. We’re on the cusp of returning to the deep space because of Sam’s generation’s dedication to exploration.

Sam: The Crawler moved the Apollo/Saturn rockets and Space Shuttles to the pad, so NASA’s dedication goes back many generations. Now we will be moving SLS/Orion to the launch pad. We’re all a part of a team that believes in what we do. It will take all of our efforts, experience, knowledge, and energy, as a team, to accomplish our return to the moon successfully. I fully expect that Breanne and the other young engineers will learn, excel, and make meaningful contributions to this program as we return to the deep space exploration. We all stand on the shoulders of giants before us.

Breanne: And besides all of us at NASA, we have many international partners that are contributing. Australia is now an Artemis partner to build a moon rover, so this program will include people of various generations from many countries to benefit all of us humans.

Fast facts:

  • Weighing in at 3016 metric tonnes, the Crawler’s weight is equivalent to 20 fully-loaded 777 airplanes and it can carry 7 empty BelAZ 75710 Dump Trucks.
  • The Crawler Transporters were designed by Bucyrus Erie Company and built by Marion Power Shovel Company at a cost of US$14 million in the 1960s and became the largest self-powered land vehicle in the world.
  • The Crawler Transporter vehicle measures 40m x 35m. The height from ground level to the platform is adjustable from 6.1 to 7.9m, and it has eight tracks, two on each corner. Each track, which is adjustable, consists of 57 shoes – each weigh 907kg.
  • The Crawler Transporter is powered by four, GE 1000kW (1,341hp) DC generators, these in turn, are driven by two 2,050kW (2,750hp) V16 ALCO 251C diesel engines. The Crawler’s diesel fuel tanks hold 19,000 litres of diesel fuel, and under load it burns 296 litres per kilometre.
  • Takes over eight hours of driving to get from the Vehicle Assembly Building (VAB) to Launch Pad 39B at a speed of less than 1.6km/h. Drivers will swap out every 45 to 60 minutes to prevent fatigue.

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