Mobile Launcher major modifications to begin for SLS

by Chris Bergin

The former Ares I Mobile Launcher (ML) will soon begin major modification work – pending the status of the government shutdown – ahead of its role with the Space Launch System (SLS). Work will begin with the demolition of the launch mount, which was designed with Ares I in mind, ahead of the installation of an array of umbilical connections.

SLS Mobile Launcher:

When SLS rolls out for the first time in 2017, the huge vehicle will be already mated to its Mobile Launcher, following a stacking and integration flow within the Vehicle Assembly Building (VAB).

Z3The stack and ML will depart the famous building atop of one of the modified Crawler Transporters, making the slow crawl to the modified “clean pad” at complex 39B, where engineers will making the numerous connections between the ML and the pad electrical, hydraulic and fuelling lines.

Following integration testing, SLS – with Orion – will be readied for launch.

The ML – designed by RS&H (base and structure), along with ASRC Aerospace Corporation (prop systems etc.) – consists of the main support structure that comprises the base, tower and facility ground support systems, which include power, communications, conditioned air, water for cooling, wash-down, and was designed with ignition over-pressure protection in mind.

Hensel Phelps engineers worked on the structure at the mobile launcher park site area just north of the VAB, with trestles and girders arriving by barge in February of 2009, beginning the opening phase of work to create a base platform – one which is lighter than the current Mobile Launch Platforms (MLPs) that previously hosted the Space Shuttle stack.

ML Under ConstructionWith the giant Launch Umbilical Tower (LUT), the total weight of the structure came in at around 9.5 million pounds, compared to the 8.2 million pounds for just the Shuttle’s MLP.

Fabrication of the 345-foot LUT begin in May of 2009, in preparation for being placed on top of the ML’s platform as the LUT’s base, prior to the addition of nine additional sections via a giant crane at the build site.

The installation of the first section was conducted on September 24, followed by a second section on October 15, a third on October 27, a fourth and fifth section in November, a sixth and seventh in December, followed by the final three sections, resulting all 10 sections being installed by January 28, 2010.

This was followed by the installation of the launch mount – highly specific for only the since-cancelled Ares I vehicle – on the platform in the Spring of 2010.

Ares 1 on ML with Roller Coaster EESHowever, the cancellation of the Constellation Program (CxP) resulted in the ML receiving its pink slip.

Parked up near the VAB, rumors of what would happen to the ML ranged from pulling the structure apart for scrap, through to a joke that was circulated throughout the KSC workforce claiming there was interest from Disney for turning it into a fun ride.

Ironically, Disney engineers had already worked with the KSC team on the roller coaster Emergency Egress System (EES) – a giant structure that is still in the running to be the EES for the SLS.

ML Launch Mount, via L2Although the ML is highly suited to the SLS vehicle, modifications – mainly to the Ares-specific elements of the structure, such as the launch mount – will be required, ahead of the Heavy Lift Launch Vehicle’s debut in 2017.

The launch mount will be the first major element of the ML to be redesigned, with “demolition” work set to be begin next month.

The start date will be dependent on the status of the government shutdown, which resulted in KSC contractors being locked out of the center on Tuesday.

“Modifications to the Ares 1 Mobile Launcher for SLS / NASA Contracting Office: The mobile launcher (ML) is undergoing a major upgrade in support of the Ground Systems Development and Operations Program. Construction activities at the ML east park site require the area to be designated a construction zone,” noted L2’s KSC status information.

“Modifications to the Mobile launcher will occur at the East Park Site and the surrounding area is a designated construction site and lay down yard for materials and equipment.”

Such modification planning has been taking place in addition to the umbilical set up required for SLS – a completely different set up to that planned for Ares I.

An array of connections will be installed during the modification work, from the bottom up, including two Tail Service Mast Umbilicals (TSMUs) – one for the Liquid Oxygen and one for the Liquid Hydrogen fuels to be used by SLS.

Z4New CAD images (acquired by L2) show the large structures – that will be key to fuelling the Heavy Lift Launch Vehicle (HLV) – will be placed near the aft of the vehicle, located on the same side of the vehicle, on the south side of the ML, opposite the umbilical tower.

Initial baseline configuration models indicate that the TSMUs will be placed +/- 12.7 degrees from Center Line (CL) with respect to the north/south CL of the vehicle – with the LO2 umbilical in the south west location and the LH2 umbilical in the south east location.

Also to be located on the ML’s Zero Deck will be two Aft Skirt Umbilical (ASU) units, both of which will provide electrical, GN2 purge, and data connections to the boosters during processing and countdown operations.

The twin Solid Rocket Boosters (SRBs) will be held down on the structure via Vehicle Support Posts (VSPs), providing a weight-of-vehicle-only support pedestal for the SRBs – with a Ground Support Equipment bolt inserted through the VSPs and SRB for rollout operations stability only.

No specific date has been provided as to when the modifications will be complete, although it is understood this element of the SLS Program will be ready in time to support the opening SLS launch in 2017.

(Images: Via NASA and L2 content from L2′s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site.)

(L2 is – as it has been for the past several years – providing full exclusive SLS and Exploration Planning coverage. To join L2, click here:

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