The examples and perspective in this article may not represent a worldwide view of the subject.(July 2021) |
Launch vehicle system tests assess the readiness of a launch system to safely reach orbit. Launch vehicles undergo system tests before they launch. Wet dress rehearsals (WDR) and more extensive static fire tests prepare fully assembled launch vehicles and their associated ground support equipment (GSE) prior to launch. The spacecraft/payload may or may not be attached to the launch vehicle during the WDR or static fire, but sufficient elements of the rocket and all relevant ground support equipment are in place to help verify that the rocket is ready for flight.
Propellant load tests and static fire tests may also be done on prototype rocket stages, in which case no fully assembled launch vehicle is involved, as is the case of the SpaceX Starship stages, the booster Super Heavy and the second stage Starship.
A wet dress rehearsal [1] is called "wet" because the liquid propellant components (such as liquid oxygen, liquid hydrogen, etc.) are loaded into the rocket during the test. In a pure wet dress rehearsal the rocket engines are not ignited. Wet dress rehearsals may be used on production launch vehicles before each flight [2] or on prototypes under development. [3]
A static fire test includes a wet dress rehearsal and adds the step of firing the engines at full thrust. [3] The engine(s) are fired for a few seconds while the launch vehicle is held firmly attached to the launch mount. This tests engine startup while measuring pressure, temperature and propellant-flow gradients, and can be performed with or without payload. The data gathered in such tests may be used to form a unique (rocket- and engine-specific) set of criteria as part of the go/no-go decision tree in the launch software that is used on launch day. Some static fire tests have fired the engines for twelve [4] and even twenty seconds, [5] although shorter firings are more typical. [6] [7]
Many launch service providers do not regularly perform wet dress rehearsals on new launch vehicles; as of 2018 [update] some regularly perform wet dress rehearsals or even full static fire tests on the launch mount. For example, SpaceX typically performs a full static fire on every new booster and also on each reflown booster before every launch, sometimes more than once. In January 2018, SpaceX did two wet dress rehearsals on the Zuma Falcon 9 mission, and conducted multiple wet dress rehearsals on the Falcon Heavy launch vehicle which had its maiden launch on 6 February 2018. Both were explicitly booked as wet dress rehearsals, but with the option to proceed to a static fire test. The second wet dress rehearsal on 24 January 2018 led to a full 12-second static fire test of the 27 engines of the Falcon Heavy — a much longer static fire test than the typical 3–7 second duration tests SpaceX uses for the Falcon 9. [8]
Wet rehearsal and static fire tests can fail catastrophically, such as that which resulted in a pad explosion of a SpaceX Falcon 9 on September 1, 2016. [9] The failure resulted from a major breach of the cryogenic helium system of the second stage during propellant-loading operations. The explosion destroyed the rocket and its payload - the AMOS-6 satellite. Furthermore, due to extensive fire, the SLC-40 launch pad was heavily damaged and had to be rebuilt. [10] [11]
Static fire test failures have resulted in the unintentional launch of the test vehicle. On June 6th, 1952, Viking 8 broke loose of its moorings during a static fire test. After 55 seconds of flight, a command was sent to cut propulsion, and the rocket crashed 4 miles (6 km) or 5 miles (8 km) downrange. [12] : 172–181 On June 30th, 2024, during a static fire test of the first stage of the Space Pioneer Tianlong-3, a structural failure between the rocket and test stand resulted in an unintentional launch. [13] [14] The rocket landed and exploded in the nearby mountains.
A reusable launch vehicle has parts that can be recovered and reflown, while carrying payloads from the surface to outer space. Rocket stages are the most common launch vehicle parts aimed for reuse. Smaller parts such as rocket engines and boosters can also be reused, though reusable spacecraft may be launched on top of an expendable launch vehicle. Reusable launch vehicles do not need to make these parts for each launch, therefore reducing its launch cost significantly. However, these benefits are diminished by the cost of recovery and refurbishment.
A launch vehicle is typically a rocket-powered vehicle designed to carry a payload from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage rocket, but the term is more general and also encompasses vehicles like the Space Shuttle. Most launch vehicles operate from a launch pad, supported by a launch control center and systems such as vehicle assembly and fueling. Launch vehicles are engineered with advanced aerodynamics and technologies, which contribute to high operating costs.
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.
Falcon 9 is a partially reusable medium-lift launch vehicle that can carry cargo and crew into Earth orbit, designed, manufactured and launched by American aerospace company SpaceX. It can also be used as an expendable heavy-lift launch vehicle. The first Falcon 9 launch was on 4 June 2010. The first Falcon 9 commercial resupply mission to the International Space Station (ISS) launched on 8 October 2012. In 2020 it became the first commercial rocket to launch humans to orbit. In 2022, it became the U.S. rocket with the most launches in history and with a near perfect safety record, having suffered two flight failures.
Falcon Heavy is a heavy-lift launch vehicle with partial reusability that can carry cargo into Earth orbit, and beyond. It is designed, manufactured and launched by American aerospace company SpaceX.
SpaceX manufactures launch vehicles to operate its launch provider services and to execute its various exploration goals. SpaceX currently manufactures and operates the Falcon 9 Block 5 family of medium-lift launch vehicles and the Falcon Heavy family of heavy-lift launch vehicles – both of which are powered by SpaceX Merlin engines and employ VTVL technologies to reuse the first stage. As of 2024, the company is also developing the fully reusable Starship launch system, which will replace the Falcon 9 and Falcon Heavy.
SpaceX has privately funded the development of orbital launch systems that can be reused many times, similar to the reusability of aircraft. SpaceX has developed technologies over the last decade to facilitate full and rapid reuse of space launch vehicles. The project's long-term objectives include returning a launch vehicle first stage to the launch site within minutes and to return a second stage to the launch pad, following orbital realignment with the launch site and atmospheric reentry in up to 24 hours. SpaceX's long term goal would have been reusability of both stages of their orbital launch vehicle, and the first stage would be designed to allow reuse a few hours after return. Development of reusable second stages for Falcon 9 was later abandoned in favor of developing Starship, however, SpaceX developed reusable payload fairings for the Falcon 9.
Since the founding of SpaceX in 2002, the company has developed four families of rocket engines — Merlin, Kestrel, Draco and SuperDraco — and is currently developing another rocket engine: Raptor, and after 2020, a new line of methalox thrusters.
SES-9 is a geostationary communications satellite operated by SES It was launched from Cape Canaveral SLC-40 by a Falcon 9 Full Thrust launch vehicle on 4 March 2016.
Falcon 9 Full Thrust is a partially reusable, medium-lift launch vehicle, designed and manufactured by SpaceX. It is the third major version of the Falcon 9 family, designed starting in 2014, with its first launch operations in December 2015. It was later refined into the Block 4 and Block 5. As of 12 July 2024, all variants of the Falcon 9 Full Thrust had performed 334 launches without only one failure of Starlink Group 9-3. Based on the Laplace point estimate of reliability, this rocket is the most reliable orbital launch vehicle in operation.
Starship is a two-stage fully reusable super heavy-lift launch vehicle under development by SpaceX. As of July 2024, it is the most massive and powerful vehicle to ever fly. SpaceX has developed Starship with the intention of lowering launch costs using economies of scale. SpaceX aims to achieve this by reusing both rocket stages, increasing payload mass to orbit, increasing launch frequency, creating a mass-manufacturing pipeline and adapting it to a wide range of space missions. Starship is the latest project in SpaceX's reusable launch system development program and plan to colonize Mars.
Falcon 9 Block 5 is a partially reusable, human-rated, two-stage-to-orbit, medium-lift launch vehicle designed and manufactured in the United States by SpaceX. It is the fifth major version of the Falcon 9 family and the third version of the Falcon 9 Full Thrust. It is powered by Merlin 1D engines burning rocket-grade kerosene (RP-1) and liquid oxygen (LOX).
SpaceX Starship flight tests include fifteen launches to date of prototype rockets during 2019–2024 for the SpaceX Starship launch vehicle development program. Eleven test flights were of single-stage Starship spacecraft flying low-altitude tests (2019–2021), while four were orbital trajectory flights of the entire Starship launch vehicle (2023–2024), consisting of a Starship spacecraft second-stage prototype atop a Super Heavy first-stage booster prototype. None of the flights to date has carried an operational payload. Additional flight tests are planned in 2024.
Raptor is a family of rocket engines developed and manufactured by SpaceX. A notable trait of this engine family is the use of a full-flow staged combustion cycle (FFSC). They are powered by cryogenic liquid methane and liquid oxygen, a mixture known as methalox.
Super Heavy is the first stage of the SpaceX Starship super heavy-lift launch vehicle, which it composes in combination with the Starship second-stage. As of 2024, Super Heavy prototypes are being flight tested. Super Heavy flew for the first time on April 20, 2023, during the first orbital launch attempt of the Starship rocket.
Starship is a spacecraft and second stage under development by American aerospace company SpaceX. Stacked atop its booster, Super Heavy, it composes the similarly named Starship super heavy-lift space vehicle. The spacecraft is designed to transport both crew and cargo to a variety of destinations, including Earth orbit, the Moon, Mars, and beyond. It is intended to enable long duration interplanetary flights for a crew of up to 100 people. It will also be capable of point-to-point transport on Earth, enabling travel to anywhere in the world in less than an hour. Furthermore, the spacecraft will be used to refuel other Starship vehicles to allow them to reach higher orbits and other space destinations. Elon Musk, the CEO of SpaceX, estimated in a tweet that 8 launches would be needed to completely refuel a Starship in low Earth orbit, extrapolating this from Starship's payload to orbit and how much fuel a fully fueled Starship contains. To land on bodies without an atmosphere, such as the Moon, Starship will fire its engines and thrusters to slow down.
SpaceX Starship integrated flight test 3 (IFT-3) was the third integrated flight test of the SpaceX Starship launch vehicle. SpaceX performed the flight test on March 14, 2024.
The SpaceX Starship integrated flight test 4 (IFT-4) was the fourth integrated flight test of a prototype Starship launch vehicle, the world's most powerful rocket. The prototype vehicles flown were the Starship Ship 29 upper-stage and Super Heavy Booster 11. SpaceX performed the flight test on June 6, 2024.