size of a exhaust duct to a rectangle stretching and strengthened the surrounding structure. SLS weighs more than twice as much as the planned Ares I rocket. The Ares I rocket would have featured a single solid-fueled first stage, while the SLS includes two large solid rocket boosters and a powerful core with four RS-25 engines. The base of the ML-1 is high, long, and wide. The ML-1 also features a Launch Umbilical Tower (LUT) with several arms that permit servicing of the SLS on the launch pad, and swing away from it at launch. In June 2019, NASA awarded a contract for the design and construction of the Mobile Launcher-2 (ML-2) for SLS Block 1B. Construction of the ML-2 began in July 2020, with the planned completion in 2023. The total cost of the ML-2 is estimated to be $450 million. Cape Canaveral Atlas V The Atlas V utilizes an MLP when launching from SLC-41. The rocket is stacked on its MLP in the Vertical Integration Facility (VIF), and is then rolled-out over to the launch pad. The design of this MLP is derived from the MLPs used by the Titan III and IV rockets. Titan III and Titan IV Titan III and Titan IV rockets launched from SLC-40 and SLC-41 utilized MLPs to decouple assembly of the launch vehicle from launch. This was meant to enable simultaneous assembly of multiple launch vehicles as part of the Titan's Integrate-Transfer-Launch (ITL) concept, allowing a high flight rate from a small number of launch pads. Vulcan United Launch Alliance's Vulcan will use an MLP similar in design to the one used by the Atlas V when launching from SLC-41, altered to support the former's larger design. The VLP (Vulcan Launch Platform) stands tall, and when complete will weigh . It will be equipped with various electronics, power-lines, and cables to support and control the rocket. For the initial Vulcan-Centaur configuration, the MLP will supply liquefied natural gas and liquid oxygen to the first stage, and liquid hydrogen and liquid oxygen to the Centaur upper stage. the basic structure has been completed, but the umbilicals and equipment have yet to be installed. Other uses Japanese H-IIA and H-IIB rockets utilize an MLP when launching from the Yoshinobu Launch Complex. The PSLV, GSLV, and GSLV Mark III rockets utilize an MLP called the Mobile Launch Pedestal. The rockets are stacked on the Mobile