Driving the world's largest vehicle will test your nerves and skills

Driving trucks and construction equipment can be challenging. Driving the world’s largest vehicle? Even more so.

NASA’s Crawler-Transporter II, the massive rocket hauler which weighs in at 6.6 million pounds unloaded, comes with quite a learning curve that calls for a high skillset from both the driver and a team of specialists that go along for the ride at the Kennedy Space Center on Merritt Island, Florida.

The youngest and sole female driver of NASA's crawler, 24-year-old Breanne Rohloff, said load impacts steering behavior. NASATwenty-four-year-old Breanne Rohloff, the crawler’s youngest-ever and only current female driver, pointed out that while the giant machine is “very exciting to drive” it comes with unique traits that have to be mastered to ensure the successful delivery of a multi-billion dollar rocket. First up is speed. There’s no pedal to the metal here. A dial is carefully rotated to the desired speed to ensure a slow and steady pace for a vehicle that tops out at 26 feet in height and spreads out far enough to fill a baseball infield.

“Typically we're not going any faster than .85, .82 miles an hour,” said Rohloff who, like other crawler specialists, works for NASA contractor Jacobs. “We can be going as slow .3 miles an hour over the road or even slower depending on load and depending on where we are [on the Crawlerway], whether we're in a turn, whether we're crossing one of our asphalt roads or whether we're going up the pad slope. You'll go slower when you're doing those things.”

Are we there yet? takes on new meaning with the crawler which inches along on four pairs of tracks. Each pair of tracks is called a truck and weighs in at one million pounds each (see photo below).

“The crawler can go so slow you can barely tell it's moving,” said NASA senior crawler systems engineer and driver Sam Dove.

While a battered Yugo could run laps around the crawler, top speed is not the objective.