OrbitalHub

Wikipedia dicit:

Extravehicular activity (EVA) is any activity done by an astronaut or cosmonaut outside a spacecraft beyond the Earth’s appreciable atmosphere. The term most commonly applies to a spacewalk made outside a craft orbiting Earth (such as the International Space Station). On March 18, 1965, Alexei Leonov became the first human to perform a spacewalk, exiting the capsule during the Voskhod 2 mission for 12 minutes and 9 seconds. The term also applied to lunar surface exploration (commonly known as moonwalks) performed by six pairs of American astronauts in the Apollo program from 1969 to 1972. On July 21, 1969, Neil Armstrong became the first human to perform a moonwalk, outside his lunar lander on Apollo 11 for 2 hours and 31 minutes. On the last three Moon missions astronauts also performed deep-space EVAs on the return to Earth, to retrieve film canisters from the outside of the spacecraft. Astronauts Pete Conrad, Joseph Kerwin, and Paul Weitz also used EVA in 1973 to repair launch damage to Skylab, the United States’ first space station.

A “Stand-up” EVA (SEVA) is when an astronaut does not fully leave a spacecraft, but is completely reliant on the spacesuit for environmental support. Its name derives from the astronaut “standing up” in the open hatch, usually to record or assist a spacewalking astronaut.

EVAs may be either tethered (the astronaut is connected to the spacecraft; oxygen and electrical power can be supplied through an umbilical cable; no propulsion is needed to return to the spacecraft), or untethered. Untethered spacewalks were only performed on three missions in 1984 using the Manned Maneuvering Unit (MMU), and on a flight test in 1994 of the Simplified Aid For EVA Rescue (SAFER), a safety device worn on tethered U.S. EVAs.

Video Credit: NASA Johnson

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Apollo 12 was the sixth crewed flight in the United States Apollo program and the second to land on the Moon. It was launched on November 14, 1969, from the Kennedy Space Center, Florida, four months after Apollo 11. Commander Charles “Pete” Conrad and Apollo Lunar Module Pilot Alan L. Bean performed just over one day and seven hours of lunar surface activity while Command Module Pilot Richard F. Gordon remained in lunar orbit. The landing site for the mission was located in the southeastern portion of the Ocean of Storms.

On November 19 Conrad and Bean achieved a precise landing at their expected location within walking distance of the site of the Surveyor 3 robotic probe, which had landed on April 20, 1967. They carried the first color television camera to the lunar surface on an Apollo flight, but transmission was lost after Bean accidentally pointed the camera at the Sun and the camera’s sensor was destroyed. On one of two moonwalks they visited Surveyor 3 and removed some parts for return to Earth.

Lunar Module Intrepid lifted off from the Moon on November 20 and docked with the command module, which then, after completing its 45th lunar orbit, traveled back to Earth. The Apollo 12 mission ended on November 24 with a successful splashdown.

Video Credit: NASA

Wikipedia dicit:

A transit of Mercury across the Sun takes place when the planet Mercury passes directly (transits) between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a transit, Mercury appears as a tiny black dot moving across the disk of the Sun.

Transits of Mercury with respect to Earth are much more frequent than transits of Venus, with about 13 or 14 per century, in part because Mercury is closer to the Sun and orbits it more rapidly.

The most common observation to be made at a transit is to record the times when the disk of Mercury appears to be in contact with the limb of the Sun. Those contacts are traditionally referred to as the 1st, 2nd, 3rd and 4th contacts – with the 2nd and 3rd contacts occurring when the disk of Mercury is fully on the disk of the sun. As a general rule, 1st and 4th contacts cannot be accurately detected, while 2nd and 3rd contacts are readily visible within the constraints of the Black Drop effect, irradiation, atmospheric conditions, and the quality of the optics being used.

Video Credit: NASA’s Goddard Space Flight Center/Genna Duberstein

Wikipedia dicit:

The Space Launch System (SLS) is a US super heavy-lift expendable launch vehicle, which is under development as of 2019. It is the primary launch vehicle of NASA’s deep space exploration plans, including the planned crewed lunar flights of the Artemis program and a possible follow-on human mission to Mars. SLS replaces the previous Ares V launch vehicle of 2005, although it shares a number of technologies and systems.

The initial SLS Block 1 is required by the US Congress to lift a payload of 95 metric tons (209,000 lb) to low Earth orbit (LEO), and will launch Artemis 1 and Artemis 2. The later Block 1B is intended to debut the Exploration Upper Stage and launch the Artemis 3 and the notional Artemis 4-8. Block 2 is planned to replace the initial Shuttle-derived boosters with advanced boosters and would have a LEO capability of more than 150 metric tons (330,000 lb), again as required by Congress. Block 2 is intended to enable crewed launches to Mars. The SLS will launch the Orion spacecraft and use the ground operations and launch facilities at NASA’s Kennedy Space Center in Florida.

Video Credit: Aerojet Rocketdyne

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The Neutron star Interior Composition Explorer (NICER) is a NASA Explorers program Mission of Opportunity dedicated to the study of the extraordinary gravitational, electromagnetic, and nuclear physics environments embodied by neutron stars, exploring the exotic states of matter where density and pressure are higher than in atomic nuclei. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft (0.2–12 keV) X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena, and the mechanisms that underlie the most powerful cosmic particle accelerators known. NICER will achieve these goals by deploying, following launch, an X-ray timing and spectroscopy instrument as an attached payload aboard the International Space Station (ISS).

Video Credit: NASA

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Mars 2020 is a Mars rover mission by NASA’s Mars Exploration Program with a planned launch on 17 July 2020, and touch down in Jezero crater on Mars on 18 February 2021.

The mission will seek signs of habitable conditions on Mars in the ancient past, and will also search for evidence—or biosignatures—of past microbial life. The rover is planned for launch in 2020 on an Atlas V-541, and the Jet Propulsion Laboratory will manage the mission. The mission is part of NASA’s Mars Exploration Program.

The Science Definition Team proposed that the rover collect and package as many as 31 samples of rock cores and surface soil for a later mission to bring back for definitive analysis on Earth. In 2015 they expanded the concept, planning to collect even more samples and distribute the tubes in small piles or caches across the surface of Mars.

In September 2013 NASA launched an Announcement of Opportunity for researchers to propose and develop the instruments needed, including the Sample Caching System. The science instruments for the mission were selected in July 2014 after an open competition based on the scientific objectives set one year earlier. The science conducted by the rover’s instruments will provide the context needed for detailed analyses of the returned samples. The chairman of the Science Definition Team stated that NASA does not presume that life ever existed on Mars, but given the recent Curiosity rover findings, past Martian life seems possible.

Video Credit: NASA