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Power cycling is the act of turning a piece of equipment, usually a computer, off and then on again. Reasons for power cycling include having an electronic device reinitialize its set of configuration parameters or recover from an unresponsive state of its mission critical functionality, such as in a crash or hang situation. Power cycling can also be used to reset network activity inside a modem. It can also be among the first steps for troubleshooting an issue.
Power cycling can be done manually, usually using the power switch on the device, or remotely, through some type of external device connected to the power input. [1]
In the data center environment, remote control power cycling can usually be done through a power distribution unit, over the network. In the home environment, this can be done through home automation powerline communications. Most Internet Service Providers publish a "how-to" on their website showing their customers the correct procedure to power cycle their devices.[ citation needed ]
Power cycling is a common diagnostic procedure usually performed first when a computer system freezes. However, frequently power cycling a computer can cause thermal stress. [2] Reset has an equal effect on the software but may be less problematic for the hardware as power is not interrupted.
On all Apollo missions to the moon, the landing radar was required to acquire the surface before a landing could be attempted. But on Apollo 14, the landing radar was unable to lock on. Mission control told the astronauts to cycle the power. [3] They did, the radar locked on just in time, and the landing was completed. [4]
During the Rosetta mission to comet 67P/Churyumov–Gerasimenko, the Philae lander did not return the expected telemetry on awakening after arrival at the comet. The problem was diagnosed as "somehow a glitch in the electronics", engineers cycled the power, and the lander awoke correctly. [5]
During the launch of the billion dollar [6] AEHF-6 satellite on 26 March 2020 by an Atlas V rocket from Cape Canaveral Air Force Station, a hold was called at T-46 seconds due to hydraulic system not responding as expected. The launch crew turned it off and back on, and the launch proceeded normally. [7]
In 2023 the Interstellar Boundary Explorer spacecraft stopped responding to commands after an anomaly. When gentler techniques failed, NASA resorted to rebooting the spacecraft with the remote equivalent of a power cycle. [8]
Apollo 13 was the seventh crewed mission in the Apollo space program and the third meant to land on the Moon. The craft was launched from Kennedy Space Center on April 11, 1970, but the lunar landing was aborted after an oxygen tank in the service module (SM) ruptured two days into the mission, disabling its electrical and life-support system. The crew, supported by backup systems on the lunar module (LM), instead looped around the Moon in a circumlunar trajectory and returned safely to Earth on April 17. The mission was commanded by Jim Lovell, with Jack Swigert as command module (CM) pilot and Fred Haise as lunar module (LM) pilot. Swigert was a late replacement for Ken Mattingly, who was grounded after exposure to rubella.
Apollo 14 was the eighth crewed mission in the United States Apollo program, the third to land on the Moon, and the first to land in the lunar highlands. It was the last of the "H missions", landings at specific sites of scientific interest on the Moon for two-day stays with two lunar extravehicular activities.
Deep Space 1 (DS1) was a NASA technology demonstration spacecraft which flew by an asteroid and a comet. It was part of the New Millennium Program, dedicated to testing advanced technologies.
A spacecraft is a vehicle that is designed to fly and operate in outer space. Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle.
Ranger 3 was a space exploration mission conducted by NASA to study the Moon. The Ranger 3 robotic spacecraft was launched January 26, 1962 as part of the Ranger program. Due to a series of malfunctions, the spacecraft missed the Moon by 22,000 mi (35,000 km) and entered a heliocentric orbit.
The Apollo Lunar Module, originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed spacecraft to operate exclusively in the airless vacuum of space, and remains the only crewed vehicle to land anywhere beyond Earth.
Soyuz is a series of spacecraft which has been in service since the 1960s, having made more than 140 flights. It was designed for the Soviet space program by the Korolev Design Bureau. The Soyuz succeeded the Voskhod spacecraft and was originally built as part of the Soviet crewed lunar programs. It is launched on a Soyuz rocket from the Baikonur Cosmodrome in Kazakhstan. Between the 2011 retirement of the Space Shuttle and the 2020 demo flight of SpaceX Crew Dragon, the Soyuz served as the only means to ferry crew to or from the International Space Station, for which it remains heavily used. Although China did launch crewed Shenzhou flights during this time, none of them docked with the ISS.
AS-201, flown February 26, 1966, was the first uncrewed test flight of an entire production Block I Apollo command and service module and the Saturn IB launch vehicle. The spacecraft consisted of the second Block I command module and the first Block I service module. The suborbital flight was a partially successful demonstration of the service propulsion system and the reaction control systems of both modules, and successfully demonstrated the capability of the command module's heat shield to survive re-entry from low Earth orbit.
A countdown is a sequence of backward counting to indicate the time remaining before an event is scheduled to occur. NASA commonly employs the terms "L-minus" and "T-minus" during the preparation for and anticipation of a rocket launch, and even "E-minus" for events that involve spacecraft that are already in space, where the "T" could stand for "Test" or "Time", and the "E" stands for "Encounter", as with a comet or some other space object.
The Apollo primary guidance, navigation, and control system was a self-contained inertial guidance system that allowed Apollo spacecraft to carry out their missions when communications with Earth were interrupted, either as expected, when the spacecraft were behind the Moon, or in case of a communications failure. The Apollo command module (CM) and lunar module (LM), were each equipped with a version of PGNCS. PGNCS, and specifically its computer, were also the command center for all system inputs from the LM, including the alignment optical telescope, the radar system, the manual translation and rotation device inputs by the astronauts as well as other inputs from the LM systems.
Flight controllers are personnel who aid space flight by working in such Mission Control Centers as NASA's Mission Control Center or ESA's European Space Operations Centre. Flight controllers work at computer consoles and use telemetry to monitor various technical aspects of a space mission in real-time. Each controller is an expert in a specific area and constantly communicates with additional experts in the "back room". The flight director, who leads the flight controllers, monitors the activities of a team of flight controllers, and has overall responsibility for success and safety.
In a computer or data transmission system, a reset clears any pending errors or events and brings a system to normal condition or an initial state, usually in a controlled manner. It is usually done in response to an error condition when it is impossible or undesirable for a processing activity to proceed and all error recovery mechanisms fail. A computer storage program would normally perform a "reset" if a command times out and error recovery schemes like retry or abort also fail.
John Royer Garman was a computer engineer, former senior NASA executive and noted key figure of the Apollo 11 lunar landing. As a young specialist on duty during the final descent stage on 20 July 1969 he dealt with a series of computer alarms which could have caused the mission to be aborted.
The LK was a lunar module developed in the 1960s as a part of several Soviet crewed lunar programs. Its role was analogous to the American Apollo Lunar Module (LM). Three LK modules, of the T2K variant, were flown without crew in Earth orbit, but no LK ever reached the Moon. The development of the N1 launch vehicle required for the lunar flight suffered setbacks, and the first Moon landings were achieved by US astronauts on Apollo 11. As a result, having lost the Space Race, both the N1 and the LK programs were cancelled without any further development.
A rover is a planetary surface exploration device designed to move over the rough surface of a planet or other planetary mass celestial bodies. Some rovers have been designed as land vehicles to transport members of a human spaceflight crew; others have been partially or fully autonomous robots. Rovers are typically created to land on another planet via a lander-style spacecraft, tasked to collect information about the terrain, and to take crust samples such as dust, soil, rocks, and even liquids. They are essential tools in space exploration.
The Soyuz-TMA is a spacecraft used by the Russian Federal Space Agency for human spaceflight. It is a revision of the Soyuz spacecraft and was superseded in 2010 by the Soyuz TMA-M.(T – транспортный – Transportnyi – meaning transport, M – модифицированный – Modifitsirovannyi – meaning modified, A – антропометрический, – Antropometricheskii meaning anthropometric). The spacecraft features several changes to accommodate requirements requested by NASA in order to service the International Space Station, including more latitude in the height and weight of the crew and improved parachute systems. It is also the first expendable vehicle to feature a "glass cockpit". Soyuz-TMA looks identical to the earlier Soyuz-TM spacecraft on the outside, but interior differences allow it to accommodate taller occupants with new adjustable crew couches.
A gravity turn or zero-lift turn is a maneuver used in launching a spacecraft into, or descending from, an orbit around a celestial body such as a planet or a moon. It is a trajectory optimization that uses gravity to steer the vehicle onto its desired trajectory. It offers two main advantages over a trajectory controlled solely through the vehicle's own thrust. First, the thrust is not used to change the spacecraft's direction, so more of it is used to accelerate the vehicle into orbit. Second, and more importantly, during the initial ascent phase the vehicle can maintain low or even zero angle of attack. This minimizes transverse aerodynamic stress on the launch vehicle, allowing for a lighter launch vehicle.
NASA's Christopher C. Kraft Jr. Mission Control Center, also known by its radio callsign, Houston, is the facility at the Lyndon B. Johnson Space Center in Houston, Texas, that manages flight control for the United States human space program, currently involving astronauts aboard the International Space Station (ISS). The center is in Building 30 at the Johnson Space Center and is named after Christopher C. Kraft Jr., a NASA engineer and manager who was instrumental in establishing the agency's Mission Control operation, and was the first Flight Director.
Globus IMP instruments were spacecraft navigation instruments used in Soviet and Russian crewed spacecraft. The IMP acronym stems from the Russian expression Indicator of position in flight, but the instrument is informally referred to as the Globus. It displays the nadir of the spacecraft on a rotating terrestrial globe. It functions as an onboard, autonomous indicator of the spacecraft's location relative to Earth coordinates. An electro-mechanical device in the tradition of complex post-World War II clocks such as master clocks, the Globus IMP instrument incorporates hundreds of mechanical components common to horology. This instrument is a mechanical computer for navigation akin to the Norden bombsight. It mechanically computes complex functions and displays its output through mechanical displacements of the globe and other indicator components. It also modulates electric signals from other instruments.
A ground segment consists of all the ground-based elements of a space system used by operators and support personnel, as opposed to the space segment and user segment. The ground segment enables management of a spacecraft, and distribution of payload data and telemetry among interested parties on the ground. The primary elements of a ground segment are: