Spaceflight Insider

Kennedy Space Center highlights progress of SLS’ Mobile Launcher

A view of the sky from NASA's Mobile Launcher. Photo Credit: Michael / Seeley

A view of the sky from NASA’s Mobile Launcher. Photo Credit: Michael / Seeley

KENNEDY SPACE CENTER, Fla — NASA hosted an event near the agency’s Kennedy Space Center Launch Complex 39B providing an update on upgrades that have been made to the Mobile Launcher or “ML”. The structure has been in a state of ongoing development since the close of the Space Shuttle program in 2011. Now, it is being refurbished to help enable the agency’s human deep space exploration ambitions.

“One of the things that you don’t see on the ML right now are the umbilicals; the umbilicals are the arms that support the vehicle, and they pass commodities back and forth between the vehicle – those will be the last thing that we put on,” the Mobile Launcher Element Project Manager Eric Ernst said. “They’re still undergoing fabrication, they will go through the Launch Equipment Test Facility for qualification testing before they come to us, and then we’ll install them out here.”

Shots from the tour of the Mobile Launch Platform that will launch the SLS rocket. Photo Credit Michael Seeley SpaceFlight Insider

The Mobile Launcher has been renovated from its previous use with the Ares I rocket to support the new Space Launch System. Photo Credit: Michael Seeley / SpaceFlight Insider

During the Thursday, Aug. 19 interview, Ernst noted the difficulty involved in such an effort.

“That will be a big crane event to accomplish because these are big, heavy arms,” Ernst said.

He went on to say that the total cost of the project stood at present at about $211 million. When all is said and done, the total cost to have the Mobile Launcher able to support NASA’s new Space Launch System (SLS) super heavy-lift rocket should stand at approximately $350 million.

“We have just finished a major structural steel upgrade; the original launcher was built to support Ares, a much lighter vehicle. So, the first step we took was to adapt the ML to handle a much larger and heavier vehicle,” Ernst said.

Engineers working on the project had to deconstruct the ML’s base and then rebuild it, with the capability of supporting the far larger SLS booster. When fully fueled, it is estimated that the SLS rocket will weigh in at approximately five and a half million lbs (2,494,758 kg). By comparison, engineers working on this project estimated that Ares I weighed about 2 million lbs (907,184 kg).

“The structural engineering guys had quite a challenge – they had to take the entire structure from the tower forward apart, without it falling over, without it moving, without it settling, and then rebuild it. So, we went through a large redesign effort and a lot of analyses, our construction contractor went through a lot of shop work to deal with, to support the Mobile Launcher during the construction phase, and this is the culmination of all of that work – we literally are finishing up this week,” Ernst said gesturing up toward the ML.

To get the Mobile Launcher ready to handle SLS, engineers had to complete about a year’s worth of design work, it then took them about a year and a half to finish the current stage of construction.

NASA is hoping that its ongoing efforts will not meet the same fate as its last crew-rated deep space initiative (the now-cancelled Constellation Program). During the seven years and roughly $9 billion that started when then-President Bush announced NASA would redirect its energies to points beyond low-Earth orbit (LEO), the space agency invested considerable effort with new vehicles being developed and tested to send crews to the Moon, Mars, and points beyond.

It was not to be, however. President Barack Obama attempted to cancel all elements of Constellation. Congress felt that all of that effort should not go to waste. The Orion Multi-Purpose Crew Vehicle, now simply referred to as Orion, was saved. Meanwhile, the Ares V heavy-lift booster was revamped, redesigned, and is now, essentially, the SLS.

Private firms are currently developing spacecraft, most notably, SpaceX’s Dragon and Boeing’s CST-100 spacecraft; they will be tasked with delivering astronauts to LEO. In theory, NASA should now be free to pick up the task it had set down on December 19, 1972 – sending astronauts to points beyond Earth’s gravitational sphere of influence.

In terms of the ML, the next stage of development involves the inclusion of the various equipment meant to support the SLS launch vehicle. Electrical, fluid, and cryogenics components will now be incorporated into the Mobile Launcher in preparation for the first flight of SLS, Exploration Mission 1 or “EM-1” – currently slated to take place in November of 2018.

The Mobile Launcher had to be modified from a booster with a single with a single thrust chamber - for one with three. Photo Credit: Micheal Howard / SpaceFlight Insider

The Mobile Launcher had to be modified from a booster with a single thrust chamber – for one with three. Photo Credit: Micheal Howard / SpaceFlight Insider


Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

Reader Comments

Wouldn’t it have been better to simply continue manufacturing the boosters and external tank of the “Space Transportation System” shuttle, and replace the 100 ton orbiter with payload?

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