mobile launcher platform

File:LUT -1 being moved to VAB - January, 1966 (48260918472).jpg]]

From 1967 to 2011, three platforms were used at the LC-39 to support NASA's launch vehicles at the Kennedy Space Center. Formerly called Mobile Launchers (ML), the mobile launcher platforms were constructed for transporting and launching the Saturn V rocket for the Apollo program lunar landing missions of the 1960s and 1970s. Each ML originally had a single exhaust vent for the Saturn V's engines. The Mobile Launchers also featured a {{convert|380|ft|m|adj=mid|-tall}} Launch Umbilical Tower (LUT) with nine swing arms that permitted servicing of the vehicle on the launch pad, and swung away from it at launch.

The Mobile Launchers were built by Ingalls Iron Works. The swing arms were constructed by Hayes International.

After the Apollo program, the bases of the Mobile Launchers were modified for the Space Shuttle. The Launch Umbilical Towers from ML-2 and ML-3 were removed. Portions of these tower structures were erected at the two launch pads, 39A and 39B. These permanent structures were known as the Fixed Service Structures (FSS). The LUT from ML-1 was taken apart and stored in the Kennedy Space Center's industrial area. Efforts to preserve the LUT in the 1990s failed due to a lack of funding, and it was scrapped.{{Cite web|url=http://www.collectspace.com/news/news-020404a.html|title=Apollo tower proposed as monument {{!}} collectSPACE|website=collectSPACE.com|access-date=2019-12-11}}

In addition to removal of the umbilical towers, each Shuttle-era MLP was extensively reconfigured with the addition of two Tail Service Masts (TSM), one on either side of the main engine exhaust vent. These {{convert|31|ft|m|abbr=on|order=flip}} masts contained the feed lines through which liquid hydrogen (LH₂) and liquid oxygen (LOX) were loaded into the shuttle's external fuel tank, as well as electrical hookups and flares that were used to burn off any ambient hydrogen vapors at the launch site immediately prior to Main Engine start.{{Cite journal|last=Dandage|first=S. R.|title=Design and Development of the Space Shuttle Tail Service Masts|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790013204.pdf|journal=NASA Goddard Space Flight Center|date=28 April 1977|volume=Goddard Space Flight Center The 11th Aerospace Mech. Symp|pages=1–12|via=NASA NTRS}}

The main engines vented their exhaust through the original opening used for the Saturn rocket exhaust. Two additional exhaust ports were added to vent exhaust from the Space Shuttle Solid Rocket Boosters (SRBs) that flanked the external fuel tank.

The Space Shuttle assembly was held to the MLP at eight holddown points using large studs, four on the aft skirt of each Solid Rocket Booster. Immediately before SRB ignition, frangible nuts attached to the top of these studs were detonated, releasing the Shuttle assembly from the platform.{{cite web |url=http://www.nasa.gov/sites/default/files/290339main_8-388221J.pdf |title=Space Shuttle Solid Rocket Booster: Frangible Nut Crossover System |publisher=NASA |first=Steve |last=Roy |date=November 2008 |access-date=September 28, 2016 |id=NP-2008-09-143-MSFC |archive-url=https://web.archive.org/web/20170202220813/https://www.nasa.gov/sites/default/files/290339main_8-388221J.pdf |archive-date=February 2, 2017 |url-status=live}}

Each MLP weighed {{convert|8.23|e6lb|t|abbr=off}} unloaded and roughly {{convert|11|e6lb|t|abbr=off}} with an unfueled Shuttle aboard, measured {{convert|160|by|135|ft}}, and was {{convert|25|ft}} high. They were carried by one of two crawler-transporters (CT), which measure {{convert|131|by|114|ft}}, and {{convert|20|ft}} high. Each crawler weighs about {{convert|6|e6lb|t|abbr=off}} unloaded, has a maximum speed of about {{convert|1|mph}} loaded, and has a leveling system designed to keep the launch vehicle vertical while negotiating the 5 percent grade (slope) leading to the top of the launch pad. Two {{convert|2750|hp|MW}} diesel engines power each crawler.{{cite web |url=http://www-pao.ksc.nasa.gov/kscpao/nasafact/pdf/countdow.pdf |title=Countdown! NASA Launch Vehicles and Facilities |publisher=NASA |pages=16–17 |date=October 1991 |access-date=August 21, 2013 |id=PMS 018-B, section 3 |url-status=dead |archive-url=https://web.archive.org/web/20050127071338/http://www-pao.ksc.nasa.gov/kscpao/nasafact/pdf/countdow.pdf |archive-date=January 27, 2005 }}

The MLPs were designed as part of NASA's strategy for vertical assembly and transport of space vehicles. Vertical assembly allows the preparation of the spacecraft in a ready-for-launch position, and avoids the additional step of lifting or craning a horizontally-assembled vehicle onto the launchpad (as the engineers of the Soviet space program chose to do).

File:Mobile launcher platform.jpg]]

Construction of the Mobile Launcher Platform-1 (MLP-1) (formerly called the Mobile Launcher-3 or ML-3) began in 1964 and was completed with the installation of the Launch Umbilical Tower hammerhead crane on 1 March 1965.{{cite web|url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch13-3.html|title=The Swing-Arm Controversy|last=Benson|first=Charles D|author2=Faherty, William B|work=Moonport: A History of Apollo Launch Facilities and Operations|publisher=NASA History Office|access-date=2009-03-25|archive-date=2022-10-04|archive-url=https://web.archive.org/web/20221004025058/https://www.hq.nasa.gov/office/pao/History/SP-4204/ch13-3.html|url-status=dead}} The swing arms were added at a later date.

The ML-3 was used for five crewed Apollo launches; Apollo 10, Apollo 13, Apollo 15, Apollo 16 and Apollo 17.

Following the launch of Apollo 17, the ML-3 was the first of the Mobile Launchers to be converted for use by the Space Shuttle. The Launch Umbilical Tower was dismantled and later partially reassembled on LC-39A{{Cite web|url=https://www.nasa.gov/centers/kennedy/images/content/479677main_108-KSC-77P-160.jpg|title=Photo of ML2/LUT2 on LC-39A AFTER the FSS was constructed.|access-date=2019-12-29|archive-date=2016-03-28|archive-url=https://web.archive.org/web/20160328082653/http://www.nasa.gov/centers/kennedy/images/content/479677main_108-KSC-77P-160.jpg|url-status=dead}} as that pad's Fixed Service Structure (FSS) and the base of the launch platform was modified to accommodate the locations of engines on the Shuttle. The platform was redesignated MLP-1.

In total, the MLP-1 was used for 52 Shuttle launches between 1981 and 2009. It was used for the first Space Shuttle launch, STS-1, in April 1981. Following the launch of STS-119 in March 2009, it was transferred to the Constellation program. The platform was used only for the Ares I-X and the MLP-1 suffered substantial damage. The canceled Ares I-Y would have used the same MLP.{{Cite web|url=https://www.nasaspaceflight.com/2009/10/pad-39b-suffers-substantial-damage-ares-i-x-parachute-update/|title=Pad 39B suffers substantial damage from Ares I-X launch - Parachute update|date=2009-10-31|website=NASASpaceFlight.com|language=en-US|access-date=2019-12-11}}{{Cite web|url=https://www.nasaspaceflight.com/2008/07/ares-i-rollercoaster-ees-continues-to-evolve/|title=Ares I Rollercoaster EES continues to evolve|date=2008-07-08|website=NASASpaceFlight.com|language=en-US|access-date=2019-12-11}} However, the Constellation program was canceled and the MLP was left unused.

Following the STS-135, usable parts from the MLP-1 were removed and stored in the Vehicle Assembly Building, with no plans to use the MLP again.{{Cite web|url=https://www.nasa.gov/exploration/systems/ground/mlp_hardware.html|title=NASA - Mobile Launcher Platforms Prepped for New Generation|last=KSC|first=Anna Heiney|website=www.nasa.gov|language=en|access-date=2018-08-28|archive-date=2019-04-20|archive-url=https://web.archive.org/web/20190420060651/https://www.nasa.gov/exploration/systems/ground/mlp_hardware.html|url-status=dead}}

In 2021, NASA began rolling out Mobile Launch Platform-1 on Crawler transporter-2 with a concrete ballast on the top to condition the crawlerway to handle the combined weight of the Space Launch System and Orion spacecraft in the future.{{Cite tweet |author=NASA's Exploration Ground Systems |user=NASAGroundSys |number=1384500006611128321 |title=Crawler transporter-2 and mobile launch platform 1 with concrete ballast completing the crawlerway conditioning recently. 25.5 million pounds were applied to the crawlerway to ready it for the massive weight of the @NASA_SLS and @NASA_Orion stack for Artemis I.}} NASA stated that re-conditioning of the crawlerway will be required periodically in the future, and MLP-1 will be retained for that purpose. MLP-1 will be stored in High Bay 1 of the Vehicle Assembly Building when not in use for crawlerway maintenance.{{Cite web|url=http://www.collectspace.com/news/news-011921a-mobile-launch-platform-2-demolition.html|title=Out of space, NASA is demolishing Apollo, shuttle launch platform |website=www.collectspace.com|language=en|date=19 January 2021|access-date=19 November 2021}}{{cite web|url=https://bigthink.com/the-present/mobile-launcher-nasa/|title=NASA is destroying this iconic launcher platform|website=bigthink.com|date=22 January 2021|access-date=19 November 2021}}

File:Atlantis on Crawler Transporter on its way to pad 39A.jpg]]

Mobile Launcher Platform-2 (MLP-2) (formerly called the Mobile Launcher-2 or ML-2) was used for the uncrewed Apollo 6 mission, followed by three crewed Apollo launches; Apollo 9, Apollo 12 and Apollo 14. It was subsequently used for the launch of Skylab on a Saturn V in 1973.

Following the launch of Skylab, ML-2 was the second of the Mobile Launchers to be converted for use by the Space Shuttle. The Launch Umbilical Tower was dismantled and partially reassembled to become the LC-39B{{cite web|url=https://www.nasa.gov/centers/kennedy/images/content/479677main_108-KSC-77P-160.jpg|title=Photo of ML2/LUT2 on LC-39A AFTER the FSS was constructed.|access-date=2019-12-29|archive-date=2016-03-28|archive-url=https://web.archive.org/web/20160328082653/http://www.nasa.gov/centers/kennedy/images/content/479677main_108-KSC-77P-160.jpg|url-status=dead}} Fixed Service Structure (FSS), and the base of the launch platform was modified to accommodate the locations of engines on the Shuttle. The platform was redesignated MLP-2.

In total, MLP-2 was used for 44 Shuttle launches, starting in 1983. All of the orbiters except {{OV|102|full=no}} made their maiden flights from MLP-2. It was also the launch site for the ill-fated STS-51L mission, when {{OV|099}} disintegrated shortly after launch, killing all seven crew members.{{cite web |title=Apollo to OmegA: NASA signs over legacy launcher for new rocket {{!}} collectSPACE |url=http://www.collectspace.com/news/news-081619a-northrop-grumman-omega-mlp-vab.html |website=collectSPACE.com |access-date=21 January 2020}}

Following the Space Shuttle retirement, NASA kept the MLP-2 for liquid-propellant rockets, but in January 2021, NASA announced that due to lack of storage space, the massive structure would be demolished.{{Cite web|url=http://www.collectspace.com/news/news-011921a-mobile-launch-platform-2-demolition.html|title=Out of space, NASA is demolishing Apollo, shuttle launch platform |website=www.collectspace.com|language=en|access-date=2021-01-20}}

File:Apollo 11 rollout (KSC-69PC-0234).jpg is carried atop the ML-1 in the lead-up to Apollo 11]]

The first launch from the Mobile Launcher Platform-3 (MLP-3) (formerly called the Mobile Launcher-1 or ML-1) was the maiden flight of the Saturn V, and the first launch from LC-39, Apollo 4. Following this, it was used for two crewed Apollo launches: Apollo 8 and Apollo 11. After NASA decided to move Saturn IB launches from LC-34 to LC-39B, the ML-1 was modified by the addition of a structure known as the Milkstool, which allowed the Saturn IB to use the same Launch Umbilical Tower as the much larger Saturn V. Three crewed flights to Skylab, and the Apollo launch for the Apollo-Soyuz Test Project, were conducted from the ML-1 using the Milkstool.

Prior to the scrapping of the LUT in 2004, there was a campaign to rebuild and preserve it as a memorial to Project Apollo.{{cite web|url=http://www.savethelut.org/|title=Welcome Page|date=2004-02-12|publisher=Save the LUT Campaign|access-date=2009-03-26|archive-date=2019-10-28|archive-url=https://web.archive.org/web/20191028070746/http://www.savethelut.org/|url-status=dead}} The crew access arm is preserved at the Kennedy Space Center Visitor Complex on the upper level of the gift shop.{{Cite web|url=http://www.collectspace.com/news/news-062918a-kennedy-space-shop-apollo11-gantry.html|title=Apollo 11 gantry arm lands in NASA gift shop (but not for sale) {{!}} collectSPACE|website=collectSPACE.com|access-date=2018-08-28}}

Following the launch of Apollo-Soyuz, ML-1 was the last Mobile Launcher to be converted for use by the Space Shuttle. The LUT and Milkstool were dismantled and placed into storage, and the base of the launch platform was modified to accommodate the locations of engines on the shuttle. The platform was redesignated MLP-3.

In total, MLP-3 was used for 29 Shuttle launches, starting in 1990. It was the least used of the three MLPs. Following the Space Shuttle retirement, NASA kept the MLP-3 for solid-propellant rockets.

Usage of MLP-3 to launch the OmegA rocket was granted to Orbital ATK (later bought out by Northrop Grumman) following discussions in 2016,{{cite web |last=Clark |first=Stephen |url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/ |title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher |work=Spaceflight Now |date=April 21, 2016 |access-date=September 11, 2020}} and later formalized through a Reimbursable Space Act Agreement in August 2019.{{cite web |url=https://www.nasa.gov/sites/default/files/atoms/files/kennedy_annual_report_fy19_web.pdf |title=2019 Kennedy Space Center Annual Report |work=NASA |pages=12–17 |date=November 19, 2019 |access-date=September 11, 2020}} Under the Agreement, Vehicle Assembly Building High Bay 2 would be used to assemble the rocket, while MLP-3 and crawler-transporter 1 would be used to move the rocket to LC-39B for launch. From 2019 to 2020, the OmegA launch tower was under construction on MLP-3. Following the cancellation of OmegA in September 2020, work began to demolish the half-completed launch tower.{{cite web |last=Bergin |first=Chris |url=https://www.nasaspaceflight.com/2020/09/omega-mlp-ksc-39b-multi-user-pad/ |title=OmegA Launch Tower to be demolished as KSC 39B fails to become a multi-user pad |work=NASASpaceFlight |date=September 11, 2020 |access-date=September 11, 2020}} As of January 2021, MLP-3 is planned to be placed in storage in High Bay 2 of the Vehicle Assembly Building. In 2023, MLP-3 was demolished to make room in High Bay 2 for other NASA operations.{{Cite web |title=NASA platform used to launch Apollo 11 to the moon set for demolition |url=http://www.collectspace.com/news/news-050823a-mobile-launch-platform-3-demolition.html |access-date=2024-12-13 |website=collectSPACE.com}}

File:Mobile Launcher for SLS in August 2015.jpg

{{main|Exploration Ground Systems#Launch platforms}}

Between 2009 and 2010, a mobile launcher platform called the Mobile Launcher-1 (ML-1) was constructed as part of the Constellation program. Since the cancellation of the program in 2010, ML-1 was converted for the Space Launch System Block 1, with various phases of construction between 2013 and 2018. The total cost of the ML-1 is estimated to be $1 billion.{{cite web|first1=Chris|last1=Bergin|access-date=2020-09-12|title=Second SLS Mobile Launcher preps for construction as hardware arrives at KSC|url=https://www.nasaspaceflight.com/2020/07/second-ml-preps-construction-hardware-ksc/|date=2020-07-06}}

The biggest modification to the ML-1 was on the platform's base, where engineers increased the size of a {{convert|22|ft2}} exhaust duct to a rectangle stretching {{convert|60|by|30|ft}} 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 {{convert|25|ft}} high, {{convert|158|ft}} long, and {{convert|133|ft}} wide.{{cite web|title=NASA Facts: Mobile Launcher |url=https://www.nasa.gov/sites/default/files/718660main_mobile-launcher.pdf|publisher=NASA|access-date=November 20, 2022}} The ML-1 also features a {{convert|355|ft|m|adj=mid|-tall}} Launch Umbilical Tower (LUT) with several arms that permit servicing of the SLS on the launch pad, and swing away from it at launch.

File:SLS Block 1B with launch tower.jpg

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 was originally estimated to be $450 million, however cost overruns have seen this increase to a projected $1.8 to $2.7 billion, and a delay until 2027 or 2029. {{cite report|title=Final Report - IG-24-016 - NASA's Management of the Mobile Launcher 2 Project

|url=https://oig.nasa.gov/wp-content/uploads/2024/08/ig-24-016.pdf|publisher=NASA|date=August 27, 2024 |access-date=February 23, 2025}}

File:Atlas V rollout with LRO and LCROSS.jpg]]

The Atlas V utilizes an MLP when launching from SLC-41. The rocket is stacked on its MLP in the {{convert|85.4|m|ft|adj=mid|-tall|order=flip}} Vertical Integration Facility (VIF), and is then rolled-out over {{convert|550|m|yd|order=flip}} to the launch pad.{{cite web |title=Atlas 5 Data Sheet |url=https://www.spacelaunchreport.com/atlas5.html |website=www.spacelaunchreport.com |access-date=24 November 2019}} The design of this MLP is derived from the MLPs used by the Titan III and IV rockets.

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.{{cite web |last1=Vobejda |first1=W. F. |last2=Rothermel |first2=L. J. |title=Positioning and Aligning the 250 Ton Solid Rocket Motors for Titan IIIC |url=https://commons.erau.edu/cgi/viewcontent.cgi?article=3080&context=space-congress-proceedings |access-date=24 November 2019 |page=258 |format=pdf |date=7 March 1966}}

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){{cite web | url=https://blog.ulalaunch.com/blog/vulcan-centaur-first-demonstration-of-launch-day-completed | title=Vulcan: First demonstration of launch day completed }} stands {{convert|183|ft|m|abbr=on}} tall, and when complete will weigh {{convert|1.3|e6lb|t|abbr=off}}. 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. {{As of|2019|October|24|df=US|post=,}} the basic structure has been completed, but the umbilicals and equipment have yet to be installed.{{cite web |title=Construction milestone achieved for Vulcan's launch platform |url=https://www.ulalaunch.com/explore/blog-detail/blog/2019/10/24/construction-milestone-achieved-for-vulcan's-launch-platform |website=www.ulalaunch.com |access-date=24 November 2019 |date=24 October 2019}} As of 2024, there are two VLP’s allowing for parallel processing.{{Cite news |title=The addition of Vulcan Launch Platform-2, or VLP-2, will help establish Lane 2 |newspaper=X (Formerly Twitter) |url=https://x.com/ulalaunch/status/1792636845794140642 }}

File:Full view of GSLV-F08 on Mobile Launch Pedestal proceeding towards the Umbilical Tower.jpg rocket is carried atop the Mobile Launch Pedestal to the Second Launch Pad]]

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.{{cite web|access-date=2020-09-11|title=GSLV-F08/GSAT-6A Mission Gallery - ISRO|url=https://www.isro.gov.in/gslv-f08-gsat-6a-mission/gslv-f08-gsat-6a-mission-gallery|website=www.isro.gov.in|archive-date=2020-08-04|archive-url=https://web.archive.org/web/20200804123802/https://www.isro.gov.in/gslv-f08-gsat-6a-mission/gslv-f08-gsat-6a-mission-gallery|url-status=dead}} The rockets are stacked on the Mobile Launch Pedestal in the Vehicle Assembly Building (VAB; not to be confused with the NASA building with the same name), and are then rolled-out towards the launch pad.{{Cite web |url=http://www.isro.org/GroundFacilities/launchfacility.aspx|title=Launch Facility|publisher=Indian Space Research Organisation|access-date=11 September 2020|url-status=dead |archive-url=https://web.archive.org/web/20100417071046/http://www.isro.org/GroundFacilities/launchfacility.aspx|archive-date=17 April 2010|df=dmy-all}}

{{Main|Sound suppression system}}

Once delivered to the pad, the mobile launcher platform is connected to the larger sound suppression system by large pipes which deliver a deluge of water from an adjacent water tower. Six {{convert|12|ft|m|adj=mid|-high}} towers known as "rainbirds" spray water over the MLP and into the flame deflector trenches below it, absorbing acoustic waves. The suppression system reduced the acoustic sound level to approximately 142 dB.{{Cite web |url=https://www.nasa.gov/mission_pages/shuttle/launch/sound-suppression-system.html |title=Sound Suppression System |series=Space Shuttle |publisher=NASA |last=Warnock |first=Lynda |access-date=October 23, 2019 |archive-date=August 10, 2020 |archive-url=https://web.archive.org/web/20200810203904/https://www.nasa.gov/mission_pages/shuttle/launch/sound-suppression-system.html |url-status=dead }}

{{NASA}}

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{{Commons category|Mobile launcher platforms}}

• {{HAER |survey=FL-4 |id=fl0302 |title=Mobile Launcher One, Kennedy Space Center, Titusville, Brevard County, FL |photos=46 |data=4 |cap=4}}

{{Apollo program hardware}}

{{Space Shuttle}}

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Category:Rocket launch technologies