Topic: Spaceflight (Page 2)

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πŸ”— J002E3

πŸ”— Spaceflight πŸ”— Astronomy

J002E3 is the designation given to an object in space discovered on September 3, 2002, by amateur astronomer Bill Yeung. Initially thought to be an asteroid, it has since been tentatively identified as the S-IVB third stage of the Apollo 12 Saturn V rocket (designated S-IVB-507), based on spectrographic evidence consistent with the titanium dioxide in the paint used on the rockets. The stage was intended to be injected into a permanent heliocentric orbit in November 1969, but is now believed instead to have gone into an unstable high Earth orbit which left Earth's proximity in 1971 and again in June 2003, with an approximately 40-year cycle between heliocentric and geocentric orbit.

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πŸ”— Apollo 15 postage stamp incident

πŸ”— United States πŸ”— Spaceflight πŸ”— Philately πŸ”— Guild of Copy Editors

The Apollo 15 postal covers incident, a 1972 NASA scandal, involved the astronauts of Apollo 15, who carried about 400 unauthorized postal covers into space and to the Moon's surface on the Lunar Module Falcon. Some of the envelopes were sold at high prices by West German stamp dealer Hermann Sieger, and are known as "Sieger covers". The crew of Apollo 15, David Scott, Alfred Worden and James Irwin, agreed to take payments for carrying the covers; though they returned the money, they were reprimanded by NASA. Amid much press coverage of the incident, the astronauts were called before a closed session of a Senate committee and never flew in space again.

The three astronauts and an acquaintance, Horst Eiermann, had agreed to have the covers made and taken into space. Each astronaut was to receive about $7,000. Scott arranged to have the covers postmarked on the morning of the Apollo 15 launch on July 26, 1971. They were packaged for space and brought to him as he prepared for liftoff. Due to an error, they were not included on the list of the personal items he was taking into space. The covers spent July 30 to August 2 on the Moon inside Falcon. On August 7, the date of splashdown, the covers were postmarked again on the recovery carrier USSΒ Okinawa. One hundred were sent to Eiermann (and passed on to Sieger); the remaining covers were divided among the astronauts.

Worden had agreed to carry 144 additional covers, largely for an acquaintance, F. Herrick Herrick; these had been approved for travel to space. Apollo 15 carried a total of approximately 641 covers. In late 1971, when NASA learned that the Herrick covers were being sold, the astronauts' supervisor, Deke Slayton, warned Worden to avoid further commercialization of what he had been allowed to take into space. After Slayton heard of the Sieger arrangement, he removed the three as backup crew members for Apollo 17, though the astronauts had by then refused compensation from Sieger and Eiermann. The Sieger matter became generally known in the newspapers in June 1972. There was widespread coverage; some said astronauts should not be allowed to reap personal profits from NASA missions.

By 1977, all three former astronauts had left NASA. In 1983, Worden sued, and the covers were returned to them. One of the postal covers given to Sieger sold for over $50,000 in 2014.

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πŸ”— Dyson sphere

πŸ”— Spaceflight πŸ”— Astronomy πŸ”— Engineering πŸ”— Astronomy/Astronomical objects

A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its power output. The concept is a thought experiment that attempts to explain how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Only a tiny fraction of a star's energy emissions reach the surface of any orbiting planet. Building structures encircling a star would enable a civilization to harvest far more energy.

The first contemporary description of the structure was by Olaf Stapledon in his science fiction novel Star Maker (1937), in which he described "every solar system... surrounded by a gauze of light traps, which focused the escaping solar energy for intelligent use." The concept was later popularized by Freeman Dyson in his 1960 paper "Search for Artificial Stellar Sources of Infrared Radiation." Dyson speculated that such structures would be the logical consequence of the escalating energy needs of a technological civilization and would be a necessity for its long-term survival. He proposed that searching for such structures could lead to the detection of advanced, intelligent extraterrestrial life. Different types of Dyson spheres and their energy-harvesting ability would correspond to levels of technological advancement on the Kardashev scale.

Since then, other variant designs involving building an artificial structure or series of structures to encompass a star have been proposed in exploratory engineering or described in science fiction under the name "Dyson sphere". These later proposals have not been limited to solar-power stations, with many involving habitation or industrial elements. Most fictional depictions describe a solid shell of matter enclosing a star, which was considered by Dyson himself the least plausible variant of the idea. In May 2013, at the Starship Century Symposium in San Diego, Dyson repeated his comments that he wished the concept had not been named after him.

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πŸ”— Apollo 11 50th Anniversary

πŸ”— Spaceflight πŸ”— Military history πŸ”— Military history/Military aviation πŸ”— Military history/Maritime warfare πŸ”— Moon πŸ”— Smithsonian Institution-related πŸ”— National Archives

Apollo 11 was the spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin formed the American crew that landed the Apollo Lunar Module Eagle on July 20, 1969, at 20:17 UTC. Armstrong became the first person to step onto the lunar surface six hours and 39 minutes later on July 21 at 02:56 UTC; Aldrin joined him 19 minutes later. They spent about two and a quarter hours together outside the spacecraft, and they collected 47.5 pounds (21.5Β kg) of lunar material to bring back to Earth. Command module pilot Michael Collins flew the Command Module Columbia alone in lunar orbit while they were on the Moon's surface. Armstrong and Aldrin spent 21 hours, 36 minutes on the lunar surface at a site they named Tranquility Base before lifting off to rejoin Columbia in lunar orbit.

Apollo 11 was launched by a Saturn V rocket from Kennedy Space Center on Merritt Island, Florida, on July 16 at 13:32 UTC, and it was the fifth crewed mission of NASA's Apollo program. The Apollo spacecraft had three parts: a command module (CM) with a cabin for the three astronauts, the only part that returned to Earth; a service module (SM), which supported the command module with propulsion, electrical power, oxygen, and water; and a lunar module (LM) that had two stagesβ€”a descent stage for landing on the Moon and an ascent stage to place the astronauts back into lunar orbit.

After being sent to the Moon by the Saturn V's third stage, the astronauts separated the spacecraft from it and traveled for three days until they entered lunar orbit. Armstrong and Aldrin then moved into Eagle and landed in the Sea of Tranquility on July 20. The astronauts used Eagle's ascent stage to lift off from the lunar surface and rejoin Collins in the command module. They jettisoned Eagle before they performed the maneuvers that propelled Columbia out of the last of its 30 lunar orbits onto a trajectory back to Earth. They returned to Earth and splashed down in the Pacific Ocean on July 24 after more than eight days in space.

Armstrong's first step onto the lunar surface was broadcast on live TV to a worldwide audience. He described the event as "one small step for [a] man, one giant leap for mankind." Apollo 11 effectively ended the Space Race and fulfilled a national goal proposed in 1961 by President John F. Kennedy: "before this decade is out, of landing a man on the Moon and returning him safely to the Earth."

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πŸ”— Flyby anomaly

πŸ”— Spaceflight πŸ”— Physics

The flyby anomaly is a discrepancy between current scientific models and the actual increase in speed (i.e. increase in kinetic energy) observed during a planetary flyby (usually of Earth) by a spacecraft. In multiple cases, spacecraft have been observed to gain greater speed than scientists had predicted, but thus far no convincing explanation has been found. This anomaly has been observed as shifts in the S-band and X-band Doppler and ranging telemetry. The largest discrepancy noticed during a flyby has been 13Β mm/s.

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πŸ”— Space Transportation System

πŸ”— United States πŸ”— Aviation πŸ”— Spaceflight πŸ”— Rocketry

The Space Transportation System (STS), also known internally to NASA as the Integrated Program Plan (IPP), was a proposed system of reusable manned space vehicles envisioned in 1969 to support extended operations beyond the Apollo program. (NASA appropriated the name for its Space Shuttle Program, the only component of the proposal to survive Congressional funding approval). The purpose of the system was twofold: to reduce the cost of spaceflight by replacing the current method of launching capsules on expendable rockets with reusable spacecraft; and to support ambitious follow-on programs including permanent orbiting space stations around the Earth and Moon, and a human landing mission to Mars.

In February 1969, President Richard Nixon appointed a Space Task Group headed by Vice President Spiro Agnew to recommend human space projects beyond Apollo. The group responded in September with the outline of the STS, and three different program levels of effort culminating with a human Mars landing by 1983 at the earliest, and by the end of the twentieth century at the latest. The system's major components consisted of:

  • A permanent space station module designed for 6 to 12 occupants, in a 270-nautical-mile (500Β km) low Earth orbit, and as a permanent lunar orbit station. Modules could be combined in Earth orbit to create a 50 to 100 person permanent station.
  • A chemically fueled Earth-to-station shuttle.
  • A chemically fueled space tug to move crew and equipment between Earth orbits as high as geosynchronous orbit, which could be adapted as a lunar orbit-to-surface shuttle.
  • A nuclear-powered ferry using the NERVA engine, to move crew, spacecraft and supplies between low Earth orbit and lunar orbit, geosynchronous orbit, or to other planets in the solar system.

The tug and ferry vehicles would be of a modular design, allowing them to be clustered and/or staged for large payloads or interplanetary missions. The system would be supported by permanent Earth and lunar orbital propellant depots. The Saturn V might still have been used as a heavy lift launch vehicle for the nuclear ferry and space station modules. A special "Mars Excursion Module" would be the only remaining vehicle necessary for a human Mars landing.

As Apollo accomplished its objective of landing the first men on the Moon, political support for further manned space activities began to wane, which was reflected in unwillingness of the Congress to provide funding for most of these extended activities. Based on this, Nixon rejected all parts of the program except the Space Shuttle, which inherited the STS name. As funded, the Shuttle was greatly scaled back from its planned degree of reusability, and deferred in time. The Shuttle first flew in 1981, and was retired in 2011.

A second part of the system, Space Station Freedom, was approved in the early 1980s and announced in 1984 by president Ronald Reagan. However, this also became politically unviable by 1993, and was replaced with the International Space Station (ISS), with substantial contribution by Russia. The ISS was completed in 2010.

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πŸ”— Starfish Prime, outer space nuclear test

πŸ”— United States πŸ”— Spaceflight πŸ”— Military history πŸ”— Military history/North American military history πŸ”— Military history/United States military history πŸ”— United States/Military history - U.S. military history πŸ”— Military history/Military science, technology, and theory πŸ”— Military history/Weaponry πŸ”— Micronesia πŸ”— Micronesia/Johnston Atoll

Starfish Prime was a July 9, 1962, high-altitude nuclear test conducted by the United States, a joint effort of the Atomic Energy Commission (AEC) and the Defense Atomic Support Agency. It was launched from Johnston Atoll and was the largest nuclear test conducted in outer space and one of five conducted by the US in space.

A Thor rocket carrying a W49 thermonuclear warhead (designed by Los Alamos Scientific Laboratory) and a Mk. 2 reentry vehicle was launched from Johnston Atoll in the Pacific Ocean, about 900 miles (1,450Β km) west-southwest of Hawaii. The explosion took place at an altitude of 250 miles (400Β km), above a point 19 miles (31Β km) southwest of Johnston Atoll. It produced a yield equivalent to 1.4Β megatonnes of TNT. The explosion was about 10Β° above the horizon as seen from Hawaii, at 11 PM Hawaii time.

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πŸ”— The Overview Effect

πŸ”— Spaceflight πŸ”— Psychology πŸ”— Spirituality

The overview effect is a cognitive shift in awareness reported by some astronauts during spaceflight, often while viewing the Earth from outer space.

It is the experience of seeing firsthand the reality of the Earth in space, which is immediately understood to be a tiny, fragile ball of life, "hanging in the void", shielded and nourished by a paper-thin atmosphere. From space, national boundaries vanish, the conflicts that divide people become less important, and the need to create a planetary society with the united will to protect this "pale blue dot" becomes both obvious and imperative.

The thing that really surprised me was that it [Earth] projected an air of fragility. And why, I don’t know. I don’t know to this day. I had a feeling it’s tiny, it’s shiny, it’s beautiful, it’s home, and it’s fragile.

Astronauts Michael Collins, Ron Garan, Rusty Schweikart, Edgar Mitchell, Tom Jones, Scott Kelly, James Irwin, Mike Massimino, AndrΓ© Kuipers, Chris Hadfield, and Sally Ride are all reported to have experienced the effect.

The term and concept were coined in 1987 by Frank White, who explored the theme in his book The Overview EffectΒ β€” Space Exploration and Human Evolution (Houghton-Mifflin, 1987), (AIAA, 1998).

In 2018, the SpaceBuzz project was created so "children around the world can also get to experience the Overview Effect." It was announced in a press release on December 20 by astronaut AndrΓ© Kuipers on the European Space Agency's (ESA) website. Spacebuzz aims to give children an overview effect like experience using virtual reality (VR) in order to have the same insight astronauts have when seeing planet Earth from space. Spacebuzz is a project started by the Overview Effect Foundation backed by ESA and the Netherlands Space Office..

In late 2019 it was reported that researchers at the University of Missouri aimed to reproduce the experience, with an isolation tank, half a tonne of Epsom salts, and a waterproof VR headset.

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πŸ”— Interplanetary Transport Network

πŸ”— Spaceflight πŸ”— Physics πŸ”— Systems πŸ”— Systems/Dynamical systems

The Interplanetary Transport Network (ITN) is a collection of gravitationally determined pathways through the Solar System that require very little energy for an object to follow. The ITN makes particular use of Lagrange points as locations where trajectories through space are redirected using little or no energy. These points have the peculiar property of allowing objects to orbit around them, despite lacking an object to orbit. While it would use little energy, transport along the network would take a long time.

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πŸ”— Porkchop plot

πŸ”— Spaceflight

A porkchop plot (also pork-chop plot) is a chart that shows contours of equal characteristic energy (C3) against combinations of launch date and arrival date for a particular interplanetary flight.

By examining the results of the porkchop plot, engineers can determine when launch opportunities exist (a launch window) that is compatible with the capabilities of a particular spacecraft. A given contour, called a porkchop curve, represents constant C3, and the center of the porkchop the optimal minimum C3. The orbital elements of the solution, where the fixed values are the departure date, the arrival date, and the length of the flight, were first solved mathematically in 1761 by Johann Heinrich Lambert, and the equation is generally known as Lambert's problem (or theorem).

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