We all know that the space shuttle needs a lot of fuel to fly into space, and the fuel is very heavy.
The currently decommissioned space shuttle has a total takeoff weight of 4.5 million pounds. Its weight comes mainly from boosters, external fuel tanks and fuel, plus the Mobile Launch Platform (MLP), and the entire assembly weighs 12.6 million pounds.
How to build a launch platform approaching 13 million pounds? How to build a transporter with an area equivalent to a baseball field?
For historical reasons, NASA developed the CT-1 and CT-2 tracked transporters . In 1967, the Saturn 5 launch vehicle sent Apollo 4 to space for the first time, and in 2011, the "Atlantis" space shuttle ignited and launched the final flight of the entire space shuttle. The biggest challenge they face is how to deal with the issue of the tracked transport vehicle equipped with the Space Launch System (SLS) rocket.
the beginning of the absurd
1964 Construction of a tracked hauler in Marion, Ohio
In the early 1960s, NASA considered several methods of transporting space vehicles, including rail and canal transport plans. Engineers were inspired by Bucyrus-Erie's massive "Big Hog" mining equipment (the "Big Hog" ran on a self-contained diesel-powered track with no connection to rail or water). In 1965, the Marion Shovel Company of Marion, Ohio, won a bid to design the Crawler- Transporters .
But 53 years ago, the crawler was built to transport Apollo spacecraft from the Kennedy Space Center's Equipment Assembly Building (VAB) to launch pads 39A and 39B, 3.4 and 4.2 miles away, respectively.
It takes about six hours for the crawler to travel from the equipment assembly building to the launch pad, and over the years, it has gone back and forth more than 300 times. The Saturn 5 launch vehicle sent Apollo 4 to space for the first time in 1967, and the space shuttle Atlantis flew STS-135 in 2011 (the 35th space shuttle mission to the International Space Station). ) is the last time. NASA estimates that each track has accumulated more than 2,200 miles on gravel.
View of the VAB (bottom) and launch pads A and B in 2005 , barely visible transporter tracks carrying the STS-114
The Crawler Transporter is the largest land motor vehicle ever built and its mission is to transport the Mobile Loading Platform to the Equipment Assembly Building and install the Mobile Launch Platform in a very on a high base .
Once the spacecraft and booster are assembled on the mobile launch platform, the track slides and secures the entire payload to its deck. The launch platform is restarted by equalizing and stabilizing the top heavy load through a laser guidance system and giant jacks.
The tracked hauler moves forward at a speed of 1 mph on the slow track covered with "Alabama River Rocks" in an Alabama quarry, spraying the rocks with water to avoid excess dust. As Road & Track magazine reported, the tracked hauler was "road tested" in the 1970s, and while it resembled a hulking mammoth, it moved every step with extreme precision, down to an eighth of an inch .
Since each launch site appears to be on top of a sloping pyramid, the transporter uses JEL to hold and secure the platform to the top. Engineers then drove it away to avoid damage during launch. Once the spacecraft is safely launched, the transport vehicle recovers the launch platform and returns to its original site.
original hybrid
In 1967, the first mission of the crawler transporter - moving the Saturn 5 rocket to the launch pad of Apollo 4
NASA program manager John Giles calls the tracked hauler a primitive hybrid. "We use generators to generate electricity, and electric motors propel the vehicle forward," he said in the journal Popular Mechanics.
This coincides with the Chevrolet Volt hybrid car concept. The crawler transporter has two V16 diesel engines at the front and rear respectively . Each end generates DC power, which is sent to 8 traction electric motors, which is enough to drive two "feet". Other diesels provide AC power for lights, computers and payloads. A huge bearing supports the two tracks. Each track contains 57 shoes, is 7.5 feet long, 1.5 feet wide, and weighs 2,100 pounds.
The 8-ton track of the transporter slaps the ground as it travels, and when a person sits on the vehicle, it feels a lot like moving slowly on a boat.
At the end of the space shuttle program in 2012, NASA extensively researched alternatives to older tracked vehicles, but concluded that they were still the most efficient way to load launch platforms, and China's space program agreed. This type of transporter is also used at the Wenchang Space Launch Site on Hainan Island, but its load is only one-third that of NASA's crawler transporter.
The future of crawler carriers
CT2 launches Launch Platform 39B during a trial run in 2015
The CT-2, which can carry 18 million pounds of payload , also needs to be upgraded with the advent of America's next-generation heavy-launch rocket, the SLS . The CT-2 adds new JEL, brakes, roller bearings, 16 transmissions and a Cummins V16 twin-turbo diesel. The CT-1 has little modification and will still be used to transport payloads for non-SLS launch rockets.
Initially the United States spent a total of $14 million to build the CT-1 and CT-2, and they did not experience much failure for more than 50 years, and are scheduled to serve another 20 years.
NASA engineers said that if they were upgraded again, it would add the top beam capacity to one of the transporters. Engineers signed their names on it and painted a 1965 Mustang emblem, viewing the CT as the most powerful hauler on the planet.
Original Author: Eric Tegler