A service structure is a permanent

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

framework or

tower A tower is a tall Nonbuilding structure, structure, taller than it is wide, often by a significant factor. Towers are distinguished from guyed mast, masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting ...

erected on a

rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...

launch pad A launch pad is an above-ground facility from which a rocket-powered missile or space vehicle is vertically launched. The term ''launch pad'' can be used to describe just the central launch platform (mobile launcher platform), or the entire c ...

that allows assembly, servicing, and crew onboarding of the

launch vehicle A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage ...

prior to liftoff. In

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

launches at the

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...

astronauts An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a List of human spaceflight programs, human spaceflight program to serve as a commander or crew member of a spa ...

enter the vehicle through a type of service structure called an " umbilical tower". Immediately before ignition of the rocket's

engines An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

, all connections between the tower and the craft are severed, and the connecting

bridges A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somet ...

swing away to prevent damage to structure and vehicle. An

elevator An elevator (American English) or lift (Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems suc ...

in the tower also allows maintenance crew to service the vehicle.

Kennedy Space Center

During the NASA

Space Shuttle program The Space Shuttle program was the fourth human spaceflight program carried out by the U.S. National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011. Its ...

, the structures at the

Launch Complex 39 Launch Complex 39 (LC-39) is a rocket launch site at the John F. Kennedy Space Center on Merritt Island, Florida, Merritt Island in Florida, United States. The site and its collection of facilities were originally built as the Apollo program's ...

pads contained a two-piece access tower system, the Fixed Service Structure (FSS) and the Rotating Service Structure (RSS). The FSS permitted access to the Shuttle via a retractable arm and a "beanie cap" to capture vented

liquid oxygen Liquid oxygen, sometimes abbreviated as LOX or LOXygen, is a clear cyan liquid form of dioxygen . It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an application which is ongoing. Physical ...

(LOX) from the

external fuel tank The Space Shuttle external tank (ET) was the component of the Space Shuttle launch vehicle that contained the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplied the fuel and oxidizer under pressure to the ...

. The RSS contained the Payload Changeout Room, which offered "clean" access to the orbiter's payload bay, protection from the elements, and protection in winds up to . The FSS on Pad 39A was repurposed the top of the umbilical tower of Mobile Launcher 2, while the FSS on 39B re-used the umbilical tower of Mobile Launcher 3. Mobile Launcher 3 would later become Mobile Launcher Platform 1 for the Shuttle. In 2011 NASA removed both the FSS and RSS from LC-39B to make way for a new generation of launch vehicles. In 2017-2018

SpaceX Space Exploration Technologies Corp., commonly referred to as SpaceX, is an America, American space technology company headquartered at the SpaceX Starbase, Starbase development site in Starbase, Texas. Since its founding in 2002, the compa ...

removed the RSS from LC-39A and modified the FSS for its new series of launch vehicles. Certain rockets such as the

Delta Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet * River delta, at a river mouth * Delta Air Lines, a major US carrier ...

and the

Saturn V The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had multistage rocket, three stages, and was powered by liquid-propel ...

use structures consisting of a fixed portion and a mobile portion; the former is the umbilical tower and the latter is known as the "mobile service tower" or "mobile service structure," but often referred to as a ''

gantry A gantry is an overhead bridge-like structure supporting equipment such as a crane, signals, or cameras. Devices and structures *Gantry (medical), cylindrical scanner assembly used for medical 3D-imaging or treatment *Gantry (transport), an over ...

''. This mobile structure is moved away from the vehicle several hours before launch.

White room

The white room was the small area used by

to access the spacecraft during human flights up through the

. The room takes its name from its white paint, which was used in

Project Gemini Project Gemini () was the second United States human spaceflight program to fly. Conducted after the first American crewed space program, Project Mercury, while the Apollo program was still in early development, Gemini was conceived in 1961 and ...

. The room was first used in

Project Mercury Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Un ...

. Its use and white color (since Gemini) continued through subsequent programs of Apollo and the Space Shuttle. Astronauts and closeout crew made their final preparations before liftoff, such as donning

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

packs, putting on

spacesuit A space suit (or spacesuit) is an environmental suit used for protection from the harsh Space environment, environment of outer space, mainly from its Vacuum (outer space), vacuum as a highly specialized pressure suit, but also its temperatu ...

helmets, and detaching portable

air-conditioning Air conditioning, often abbreviated as A/C (US) or air con (UK), is the process of removing heat from an enclosed space to achieve a more comfortable interior temperature, and in some cases, also controlling the humidity of internal air. Air c ...

units. In 2014, NASA planned to move the White Room to a museum. SpaceX launches use a rotating "Crew Access Arm" for . As of the 2020 Crew Dragon Demo-2 mission, SpaceX began calling the equivalent area of its Crew Access Arm at LC-39A the "White Room" in recognition of the original NASA structure's significance. On the first launch attempt, NASA and SpaceX flight crew began signing their respective "meatball"

NASA insignia The NASA has three official insignia, insignias, although the one with stylized red curved text (the "worm") was retired from official use from May 22, 1992, until April 3, 2020, when it was reinstated as a secondary logo. The three logos include ...

or SpaceX logos at the end of the Crew Access Arm, a practice which has become a tradition.

Baikonur Cosmodrome

Similarly, Soviet-and Russian-designed service structures such as those at

Baikonur Cosmodrome The Baikonur Cosmodrome is a spaceport operated by Russia within Kazakhstan. Located in the Kazakh city of Baikonur, it is the largest operational space launch facility in terms of area. All Russian Human spaceflight, crewed spaceflights are l ...

Site 31 feature rotating crane-like "tower arms" that stand upright to service and secure the vehicle. The tower arms then pivot outward away from the rocket at launch. https://blogs.esa.int/eolaunches/2012/09/14/metop-on-the-launch-pad/

References

{{Space Shuttle Rocket launch technologies Apollo program hardware Space Shuttle program