The NASA Crawler is the largest self-powered vehicle in the world, and is built to carry billions of dollars of spaceships and rockets.
The Crawler-transporters have been used by NASA for more than 50 years to move space shuttles and rockets across a 6.4-kilometer (four-mile) stretch to the launch pad at Kennedy Space Center in Florida.
That 6.4 kilometers can take more than 11 hours at a slower than a turtle’s pace speed of 1.6km/h.
But the Crawler is not built for speed. It’s built to carry some serious weight.
And it’s got a big job ahead in the next few days – moving the Space Launch System (SLS) – which will be used to put humans back on the moon.
How big is the NASA Crawler-transporter?
- Weight: Nearly 3,000 tonnes (6.6 million pounds – about as heavy as 15 Statues of Liberties)
- Height: About 8m tall (26 feet)
- Length: 40m (131ft)
- Width: 35m (114ft)
- Load Capacity: Able to transport 8,164 tonnes (18 million pounds)
- That’s the weight of more than 20 fully loaded 777 airplanes
- Top speed – 3.26km/h (2mph) when unloaded and 1.6km/h (1mph) loaded
It sits on four double-tank tracks. Each one is longer than a bus.
The Crawler is so huge you could fit an entire baseball infield on its back.
And there’s not just one Crawler-transporter – NASA built two of them all the way back in 1965 at a cost of $14 million.
Adjusted for inflation, that’s about $130 million in 2022 money.
And even that sounds cheap for these incredible feats of engineering.
NASA currently uses Crawler-Transport 2 (CT-2) to move the SLS – the most powerful (and heaviest) rocket the agency has ever built.
To be able to handle the 97-meter (321-feet) tall and 2,500,000kg (5.5 million pounds) SLS, NASA had to carry out some upgrades on the 57-year-old Crawler.
In 2016 the CT-2 had its chassis strengthened and improved the 16 gearboxes so it was up to the task.
The Crawler and Artemis Moon program
CT-2 will be the workhorse of NASA’s multibillion-dollar push to get humans back on the Moon – the Artemis project.
The key piece to Artemis is the SLS rocket. It will be used in an upcoming fueling test this weekend, ferried to the launch pad by the CT-2.
If all goes well, the rocket will launch unpiloted Artemis 1 sometime this summer.
Artemis 1 will send an Orion crew capsule past the moon (and back).
Then Artemis 2 will take actual astronauts up (sometime in 2024).
The plan is to have the first Artemis moon landing in 2025.
The SLS is a two-stage booster rocket that generates 8.8 million pounds of thrust (more than the Apollo Saturn V rocket).
History of the Crawler
Speaking of the Saturn V, that icon of space exploration was the exact reason the Crawlers were built for in the first place.
They were made in the early 1960s to make sure the rockets could be safely transported to the launch pad without toppling over.
To do this the Crawlers use laser guidance and a leveling system to keep everything steady.
It’s not easy when there is a 5.0-degree incline at the end of the runway track to get to the launch pads.
If the crawler tilts a tiny two inches from where it’s programmed, the whole Crawler shuts down.
Probably for the best when billions of dollars are at risk.
What’s the biggest vehicle in the world?
The Crawlers are the largest self-powered vehicles in the world.
But there is a vehicle that’s larger: the Bagger 288.
The Bagger 288 is used to move earth, literally. It’s a $100 million mining machine that weighs 12,840 tons (28 million pounds).
It’s as tall as the Statue of Liberty.
The Bagger 288 is a bucket-wheel excavator that can move 10,000 dump truck loads of earth a day.
It’s powered by an external source but it’s not self-propelled like the NASA Crawler-Transporters.