MLP-2: Launching NASAs Legacy for 50 Years

Our newest PlaneTag is more of a SpaceTag, but then again it never left earth. It just happened to be on hand for some of the most historic space launches of the 20th century. In fact, it launched the maiden voyage of every Space Shuttle (except Columbia) and launched several Apollo lunar missions and Skylab. Take a closer look at MLP-2 and find out how MotoArt acquired the material to create NASA MLP-2 PlaneTags.

What is the Mobile Launcher Platform?

The Mobile Launcher Platform, or MLP, is a two story structure which was originally built for NASA’s Apollo program to launch Saturn V rockets, and later to support the Space Shuttle stack during the build up and launch stages. The 6 million pound structure could support an additional 12 million pounds during assembly at the Vehicle Assembly Building (VAB), and while being transported to one of the Launch Pads. Once transported, the MLP served as the vehicle’s launch platform.

History of the Mobile Launcher

The Mobile Launcher was developed in 1963 to support NASA’s Apollo program. The aim of Apollo was to land mankind on the moon and return them safely to earth, and was successfully accomplished between 1968 to 1972. A Launch Operations Center (LOC) was developed at Cape Canaveral, Florida (now Cape Kennedy, home of the Kennedy Space Center), which would house Launch Complex 39, a Launch Control Center, and the VAB. The space vehicle (both the launch vehicle and spacecraft) would be assembled in the VAB on one of three Mobile Launchers (later called Mobile Launcher Platforms), then later moved to one of the several launch pads via crawler-transporter.

Saturn V Assembly

For the Saturn V launch vehicle, each stage was built by different manufacturers then shipped to the LOC for assembly. They were:

• S-IC first stage - Boeing, New Orleans, Louisiana
• S-II second stage - North American Aviation, Seal Beach, California
• S-IVB third stage - Douglas, Huntington Beach, California

The components were so large that two of them had to be shipped by barge. The S-IVB, the third stage was shipped by barge from California through the Panama Canal because it was too large and heavy to go by rail. That mode of transportation was later replaced by the Super Guppy.

At the VAB, the stages would then be placed horizontally and inspected, then assembled vertically. The Saturn V rockets were assembled this way rather than horizontally because it was felt that horizontal assembly would present too many engineering challenges.

Space Shuttle Assembly

After the Apollo program, the Mobile Launcher was then modified for use with the Space Shuttle. The Shuttle’s components were prepared for launch at the VAB.

• Orbiter - held the crew
• External Tank - held fuel for the main engines
• Solid Rocket Boosters - provided most of the lift

The SRBs would be attached to the External Tank, then Orbiter would next be mated to the external tank. This stack would be assembled on the MLP, then transported by crawler-transporter to the launch pad.

Watch this video about the MLP during the Space Shuttle Program.

MLP-2 History

MLP-2 was the second of three mobile launchers used by these programs. It was used for the following missions:

Apollo Program

As Mobile Launcher-2 (ML-2) with the Apollo Program

• Uncrewed Apollo 6 mission
• Apollo 9
• Apollo 12
• Apollo 14
• Launch of Skylab aboard a Saturn V in 1973

Space Shuttle Program

Redesignated Mobile Launcher Platform-2 (MLP-2) after conversion for use in the Space Shuttle Program

• Used for 44 Space Shuttle launches, beginning in 1983
• Every orbiter, except for Columbia, launched on their maiden flights from MLP-2
• Launch site of STS-51L (Space Shuttle Challenger) Liquid-propellant rocket launches

It was announced in January 2021 that NASA would be demolishing MLP-2 due to lack of storage space. Many aerospace enthusiasts, including MotoArt owner Dave Hall, saw the announcement and were intrigued.

MotoArt’s MLP-2

Hall was excited about the idea of having a part of such an integral part of the space program but even he was not sure where to start. He enlisted the help of two of the moderators of the fan page MotoArt PlaneTags Collections Paul Davies and Rob Schneider.

“I had seen the article posted, and I couldn't believe my eyes. I had grown up watching launches and following the Shuttle missions on TV. I had been to Cape Canaveral and took the bus tour around the complex. I had literally driven alongside the crawlerway and saw the Shuttle being escorted on an MLP. I could not believe that one of the iconic launch pads was being destroyed forever. What blew my mind even further was the fact that no one had expressed any interest in preserving her, not even the Smithsonian Museum.” - Paul Davies

Watch Dave, Paul, and Rob discuss over Zoom how they acquired the TSM from MLP-2.

Once they accessed MLP-2, the trio combed the structure to find the right material for what they envisioned.

“The first thing we noticed was how thick everything was. The door was ¾” steel. Everything was so unbelievably heavy. Once inside, it felt like we were walking around a bunker. Pipes, wires, access doors and electrical panels were everywhere… We kept saying, though, that all of those thin pieces just didn’t have any wow factor. We needed something from up top, something that would have been exposed to the launches themselves.” - Rob Schneider

What is a Tail Service Mast (TSM)?

On the MLP-2, there were two large devices which sat to either side of the main engine exhaust hole. The TSM provided umbilical connections to the orbiter - one side held a liquid-oxygen line and the other a liquid-hydrogen line - which fed the propellants from the launch pad tanks to the external tank. Other umbilicals carried helium, nitrogen, ground cooling, purge air, electrical power and comm links. The umbilicals retracted into the masts at launch and were protected from flames by protective hoods.

They were 15 feet long, 9 feet wide, and rose 31 feet above the MLP deck. They also housed six hydrogen burnoff pre-igniters, which were activated right before main engine ignition to ignite any free hydrogen that might cause rough combustion at the engine start.

“We started poking our heads into the TSM’s and measuring thicknesses of all the surfaces with our tape measures. As we were standing inside the TSM, we all came to the realization that the fuel lines laying on the ground, and the housing that we were inside was the last thing to touch Challenger. It became hallowed ground, and we were humbled by our surroundings. We knew that the TSM was what we had to make tags out of. We debated about how to make the trap doors work, measured the thicknesses of the blast doors, and the walls. Everything was thick, but we knew that we had found our material.” - Paul Davies

Manufacturing MLP-2 Planetags

The material from the TSMs had to be cut down then shipped to Mojave for handling. Once those logistical challenges were over, there were new ones to overcome. The manufacturing process for these special PlaneTags was unlike any other one before it. “We thought we had a devil of a time with our SR-71 and L-1011 PlaneTags, but this was far beyond anything we had ever worked with before,” said Hall.

The team was used to working with aluminum, not ½ inch thick hardened steel. They could not be cut or lasered in the usual manner with the equipment used in most other PlaneTag manufacturing. A new process had to be worked out to cut out the thick pieces and etch them. The packaging was also a challenge. Paper could not support such a heavy PlaneTag, so the team came up with the idea of creating a display card from aluminum.

NASA MLP-2 PlaneTags

Although the MLP-2 never left the earth, the newest PlaneTags are truly out of this world. This special edition PlaneTag will be numbered to 20,000. They are individually cut, polished and etched, then attached to an aluminum display card with a strong earth magnet. Although they can’t be used as a luggage tag or custom engraved, they are a beautiful memento of the United States’ space program of the 20th century and will make an incredible, one-of-a-kind collectible for any NASA or aerospace collector.

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