Sites for launching large rockets are often equipped with a sound suppression system to absorb or deflect acoustic energy generated during a rocket launch. As engine exhaust gasses exceed the speed of sound, they collide with the ambient air and shockwaves are created, with noise levels approaching 200 db. This energy can be reflected by the launch platform and pad surfaces, and could potentially cause damage to the launch vehicle, payload, and crew. For instance, the maximum admissible overall sound power level (OASPL) for payload integrity is approximately 145 db. [1] Sound is dissipated by huge volumes of water distributed across the launch pad and launch platform during liftoff. [2] [3]
Water-based acoustic suppression systems are common on launch pads. They aid in reducing acoustic energy by injecting large quantities of water below the launch pad into the exhaust plume and in the area above the pad. Flame deflectors or flame trenches are designed to channel rocket exhaust away from the launch pad but also redirect acoustic energy away. [2] [4]
The launch pad built by the Soviet Union beginning in 1978 at the Baikonur Cosmodrome for launching the Energiya rocket included an elaborate sound suppression system which delivered a peak flow of 18 cubic metres (4,800 US gal) per second fed by three ground level reservoirs totaling 18,000 cubic metres (4,800,000 US gal). [5]
Data from the launch of STS-1 found an overpressure wave created by the shuttle's three SSME (now designated RS-25) liquid-fueled rocket engines and the four-segment solid rocket boosters contributed to the loss of sixteen and damage to an additional 148 thermal protection tiles prompting modifications to the Sound Suppression Water System (SSWS) installed at both launch pads at Kennedy Space Center's Launch Complex 39. [6] [7]
The resulting gravity fed system, used through the remainder of the program, began release from a 300,000-US-gallon (1.1-million-litre) water tower at the launch site 6.6 seconds before main engine start through 7 feet (2.1 m) diameter pipes connected to the mobile launch platform. Water flowed out six 12-foot-high (3.7 m) towers known as "rainbirds" onto the launch platform and flame trench below, emptying the system in 41 seconds [8] with a peak flow of reducing acoustic energy levels to approximately 142 dB. [9]
The massive white clouds that billowed around the shuttle at each launch were not smoke, but wet steam generated as the rocket exhaust boiled away huge quantities of water. [10]
Launch pad 0 at the Mid-Atlantic Spaceport at NASA's Wallops Flight Facility in Virginia is equipped with a 950,000 litres (250,000 US gal) water tower 307 feet (94 m) above the ground, among the tallest in the world. Engine exhaust exits through ring of water jets in the launch platform, directly beneath engine nozzles. The system is capable of delivering 4,000 US gallons (15 m3) per second. [11] [12] Additional storage tanks totaling 100,000 US gallons (380,000 L; 83,000 imp gal) may be added for static fire tests. Water not vaporized is held in a 1,200 square metres (13,000 sq ft) retention basin where it is tested before release. [13]
Following the retirement of the Space Shuttle program, pad B at launch complex 39 was upgraded for launches of the Space Launch System (SLS). SLS features an additional RS-25 liquid-fueled rocket engine along with an additional segment in each of its solid rocket boosters over the Space Shuttle program prompting upgrades to the system creating the Ignition Over-Pressure/Sound Suppression Water System (IOP/SS).
The control system was upgraded including replacement of nearly 250 miles (400 km) of copper cables with 57 miles (92 km) of fiber optic cable. Capacity was upgraded to 400,000 US gallons (1,500,000 L) with a peak flow rate of 1,100,000 US gallons (4,200,000 L) per minute. The upgrade system was tested in December 2018 with 450,000 US gallons (1,700,000 L). [14]
JAXA "seeks to achieve the world's quietest launch" from their Noshiro Rocket Testing Center in Akita with the installation of a sound suppression water system as well as sound absorbing walls. The H3 Scaled Acoustic Reduction Experiment completed in 2017 provided additional data about the noise generated during liftoff. [15] [16]
A rocket is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely from propellant carried within the vehicle; therefore a rocket can fly in the vacuum of space. Rockets work more efficiently in a vacuum and incur a loss of thrust due to the opposing pressure of the atmosphere.
An expendable launch system is a launch vehicle that can be launched only once, after which its components are either destroyed during reentry or discarded in space. ELVs typically consist of several rocket stages that are discarded sequentially as their fuel is exhausted and the vehicle gains altitude and speed. As of 2024, less and less satellites and human spacecraft are launched on ELVs in favor of reusable launch vehicles. However, there are many instances where a ELV may still have a compelling use case over a reusable vehicle. ELVs are simpler in design than reusable launch systems and therefore may have a lower production cost. Furthermore, an ELV can use its entire fuel supply to accelerate its payload, offering greater payloads. ELVs are proven technology in widespread use for many decades.
The Space Shuttle Solid Rocket Booster (SRB) was the first solid-propellant rocket to be used for primary propulsion on a vehicle used for human spaceflight. A pair of these provided 85% of the Space Shuttle's thrust at liftoff and for the first two minutes of ascent. After burnout, they were jettisoned and parachuted into the Atlantic Ocean where they were recovered, examined, refurbished, and reused.
A solid rocket booster (SRB) is a large solid propellant motor used to provide thrust in spacecraft launches from initial launch through the first ascent. Many launch vehicles, including the Atlas V, SLS and Space Shuttle, have used SRBs to give launch vehicles much of the thrust required to place the vehicle into orbit. The Space Shuttle used two Space Shuttle SRBs, which were the largest solid propellant motors ever built and the first designed for recovery and reuse. The propellant for each solid rocket motor on the Space Shuttle weighed approximately 500,000 kilograms.
The Aerojet Rocketdyne RS-25, also known as the Space Shuttle Main Engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is used on the Space Launch System (SLS).
The F-1, commonly known as Rocketdyne F-1, is a rocket engine developed by Rocketdyne. The engine uses a gas-generator cycle developed in the United States in the late 1950s and was used in the Saturn V rocket in the 1960s and early 1970s. Five F-1 engines were used in the S-IC first stage of each Saturn V, which served as the main launch vehicle of the Apollo program. The F-1 remains the most powerful single combustion chamber liquid-propellant rocket engine ever developed.
Wallops Flight Facility (WFF) is a rocket launch site on Wallops Island on the Eastern Shore of Virginia, United States, just east of the Delmarva Peninsula and approximately 100 miles (160 km) north-northeast of Norfolk. The facility is operated by the Goddard Space Flight Center in Greenbelt, Maryland, and primarily serves to support science and exploration missions for NASA and other Federal agencies. WFF includes an extensively instrumented range to support launches of more than a dozen types of sounding rockets; small expendable suborbital and orbital rockets; high-altitude balloon flights carrying scientific instruments for atmospheric and astronomical research; and, using its Research Airport, flight tests of aeronautical research aircraft, including unmanned aerial vehicles.
The crawler-transporters, formally known as the Missile Crawler Transporter Facilities, are a pair of tracked vehicles used to transport spacecraft from NASA's Vehicle Assembly Building (VAB) along the Crawlerway to Launch Complex 39. They were originally used to transport the Saturn IB and Saturn V rockets during the Apollo, Skylab and Apollo–Soyuz programs. They were then used to transport Space Shuttles from 1981 to 2011. The crawler-transporters carry vehicles on the mobile launcher platforms used by NASA, and after each launch return to the pad to take the platform back to the VAB.
Launch Complex 39 (LC-39) is a rocket launch site at the John F. Kennedy Space Center on Merritt Island in Florida, United States. The site and its collection of facilities were originally built as the Apollo program's "Moonport" and later modified for the Space Shuttle program.
A mobile launcher platform (MLP), also known as mobile launch platform, is a structure used to support a large multistage space vehicle which is assembled (stacked) vertically in an integration facility and then transported by a crawler-transporter (CT) to a launch pad. This becomes the support structure for launch.
The Orion Multi-Purpose Crew Vehicle is equipped with a launch escape system. Orion has several abort modes. Some of these may not use the LAS itself, but would use the second stage of the SLS, or even the Orion vehicle's own propulsion system instead.
Launch Complex 39B (LC-39B) is the second of Launch Complex 39's three launch pads, located at NASA's Kennedy Space Center in Merritt Island, Florida. The pad, along with Launch Complex 39A, was first designed for the Saturn V launch vehicle, which at the time was the United States' most powerful rocket. Typically used to launch NASA's crewed spaceflight missions since the late 1960s, the pad is currently configured for use by the agency's Space Launch System rocket, a Shuttle-derived launch vehicle which is currently used in the Artemis program and subsequent Moon to Mars campaigns. The pad had also been leased by NASA to aerospace company Northrop Grumman, for use as a launch site for their Shuttle-derived OmegA launch vehicle, for National Security Space Launch flights and commercial launches, before the OmegA program was cancelled.
The Conestoga was a launch vehicle design funded by Space Services Inc. of America (SSIA) of Houston, Texas. Conestoga originally consisted of surplus LGM-30 Minuteman stages with additional strap-on boosters, as required for larger payloads. It was the world's first privately funded commercial rocket, but was launched only three times between 1981 and 1995, before the program was shut down.
In rocketry, range safety or flight safety is ensured by monitoring the flight paths of missiles and launch vehicles, and enforcing strict guidelines for rocket construction and ground-based operations. Various measures are implemented to protect nearby people, buildings and infrastructure from the dangers of a rocket launch.
The retirement of NASA's Space Shuttle fleet took place from March to July 2011. Discovery was the first of the three active Space Shuttles to be retired, completing its final mission on March 9, 2011; Endeavour did so on June 1. The final shuttle mission was completed with the landing of Atlantis on July 21, 2011, closing the 30-year Space Shuttle program.
The Space Launch System (SLS) is an American super heavy-lift expendable launch vehicle used by NASA. As the primary launch vehicle of the Artemis Moon landing program, SLS is designed to launch the crewed Orion spacecraft on a trans-lunar trajectory. The first SLS launch was the uncrewed Artemis 1, which took place on 16 November 2022.
Orbital-3, also known as Orb-3, was an attempted flight of Cygnus, an automated cargo spacecraft developed by United States-based company Orbital Sciences, on 28 October 2014. The mission was intended to launch at 22:22:38 UTC that evening. This flight, which would have been its fourth to the International Space Station and the fifth of an Antares launch vehicle, resulted in the Antares rocket exploding seconds after liftoff.
The H3 Launch Vehicle is a Japanese expendable launch system. H3 launch vehicles are liquid-propellant rockets with strap-on solid rocket boosters and are launched from Tanegashima Space Center in Japan. Mitsubishi Heavy Industries (MHI) and JAXA are responsible for the design, manufacture, and operation of the H3. The H3 is the world's first rocket to use an expander bleed cycle for the first stage engine.
NASA's Exploration Ground Systems (EGS) Program is one of three programs based at NASA's Kennedy Space Center in Florida. EGS was established to develop and operate the systems and facilities necessary to process and launch rockets and spacecraft during assembly, transport and launch. EGS is preparing the infrastructure to support NASA's Space Launch System (SLS) rocket and its payloads, such as the Orion spacecraft for Artemis I. Artemis I is the first to launch in a series of increasingly complex missions that will enable human exploration to the Moon and Mars.
A flame deflector, flame diverter or flame trench is a structure or device designed to redirect or disperse the flame, heat, and exhaust gases produced by rocket engines or other propulsion systems. The amount of thrust generated by a rocket launch, along with the sound it produces during liftoff, can damage the launchpad and service structure, as well as the launch vehicle. The primary goal of the diverter is to prevent the flame from causing damage to equipment, infrastructure, or the surrounding environment. Flame diverters can be found at rocket launch sites and test stands where large volumes of exhaust gases are expelled during engine testing or vehicle launch.