NASA's largest 2,700-ton rocket launcher

The over 50-year-old crawler carriage is refurbished and reinforced to transport NASA SLS missiles over a 7km distance to the launch pad.

When the giant missile SLS of the US Aeronautics Agency (NASA) performs its first mission, it will be taken to a launch pad by one of the largest vehicles on the planet. Controlling the vehicle requires a high degree of concentration, according to the BBC.

In the next two years, NASA plans to launch missiles in an unmanned 384,400km flight around the Moon. With the plan to build a space station, based on the Moon and Mars missions, the future of the astronaut program depends on the success of this flight.

Although SLS is a completely new missile, the multi-billion dollar 98m-high launcher will begin its journey at the Kennedy Space Center in Florida on a 50-year-old vehicle. The rocket escort team travels 7km to the launch pad and will be under great pressure.

"We have a feeling of pride when we carry the US space program on our backs," said Bob Myers, a member of NASA's massive two-wheel-drive fleet. "We only have one rocket, one launch and we don't want to spoil that launch."

The tracked vehicle was built in 1965 to transport Saturn 5 missiles carrying astronauts to the Moon and underwent revisions in the 1970s to transport shuttle spacecraft. Currently, one of the two vehicles has been refurbished and reinforced to serve the SLS missile. Despite some upgrades, the basic design of the carriage is 40 meters long, 35 meters high and weighs 2,700 tons.

"Sometimes we feel proud that tracked vehicles are made of rulers, not computers. The two vehicles are produced much better than today's vehicles and are more reliable , " Myers said.

The vehicle's specifications are impressive. Crawler vehicles operate thanks to two diesel engines that help run the generator to power 16 tow motors. Each corner has two tracks with 57 links. A sensor and lever system between the rack on the body and the rocket mounted above is always balanced throughout the journey along the gravel path and up the slope to the launch pad. The route from the assembly facility also includes many bends, meaning the track must be diverted.

"We have a team of contractors who make their way every time the carriage is ready to roll , " said John Giles, project manager of the crawler car. "When the carriage moved, it clenched on the road surface, causing gravel to crumble and shoot all over."

The vehicle is controlled from the cockpit protruding at the head and tail. When Myers first drove in 1982 to take the shuttle to the launch pad, he admitted it was an extremely stressful experience."I'm quite nervous, when you ship missiles, there's a clear sense of strength. It's not like driving a Volkswagen car," Myers said.

"The first drive is very scary and if there is a problem, we won't want to mention it for a very long time. It takes time to get used to the pressure and stress," Giles said.

NASA crawler rickshaw is one of the largest vehicles on the planet.(Photo: NASA).

Although the driver is supported by an observation team using walkie-talkies to monitor the movement of the crawler, the control has many similarities to drive. Driving using a small steering wheel with a diameter of 15cm, the clock displays the speed and brake pedal. All commands from the control panel are relatively simple to be imported into newly upgraded computer systems to ensure smooth hydraulic pump operation, enabling mechanical parts to be operated from the 1960s.

"The control system is relatively simple but has everything you need. There are many bends and many places to slow down on the journey, but it's a matter of experience and the observers will help you operate the car. " Myers explained.

Missile transportation is not something that can be done in a short time. Myers' team needs at least 7 hours to complete the journey to the launch pad. Along the way, once every two hours, the driver will change shifts but the caterpillars will still move continuously.

"We didn't stop until we got on the launch pad and unloaded the rocket. We didn't want to get bad weather and that's why we tried to get the job done as quickly and safely as we could. " Myers said.

The thousands-ton vehicle can run at 1.6 km / h is one of the greatest achievements of manufacturing engineers. NASA hopes two crawler vehicles can operate at least three decades. After the latest refurbishment, testing work is underway for the first launch of the SLS. Before transporting new missiles, the vehicle will test carrying concrete beams of similar weight.