OrbitalHub

Wikipedia dicit:

An electrically-powered spacecraft propulsion system uses electrical, and possibly also magnetic fields, to change the velocity of a spacecraft. Most of these kinds of spacecraft propulsion systems work by electrically expelling propellant (reaction mass) at high speed.

Electric thrusters typically use much less propellant than chemical rockets because they have a higher exhaust speed (operate at a higher specific impulse) than chemical rockets. Due to limited electric power the thrust is much weaker compared to chemical rockets, but electric propulsion can provide a small thrust for a long duration of time. Electric propulsion can achieve high speeds over long periods and thus can work better than chemical rockets for some deep space missions.

Electric propulsion is now a mature and widely used technology on spacecraft. Russian satellites have used electric propulsion for decades and it is predicted that by 2020, half of all new satellites will carry full electric propulsion. As of 2019, over 500 spacecraft operated throughout the Solar System use electric propulsion for station keeping, orbit raising, or primary propulsion. In the future, the most advanced electric thrusters may be able to impart a Delta-v of 100 km/s, which is enough to take a spacecraft to the outer planets of the Solar System (with nuclear power), but is insufficient for interstellar travel. An electric rocket with an external power source (transmissible through laser on the photovoltaic panels) has a theoretical possibility for interstellar flight. However, electric propulsion is not a method suitable for launches from the Earth’s surface, as the thrust for such systems is too weak.

Video credit: Aerojet Rocketdyne

NASA dicit:

Dragonfly is a NASA mission to explore the chemistry and habitability of Saturn’s largest moon, Titan. The fourth mission in the New Frontiers line, Dragonfly will send an autonomously-operated rotorcraft to visit dozens of sites on Titan, investigating the moon’s surface and shallow subsurface for organic molecules and possible biosignatures. To carry out its mission, Dragonfly is equipped with a neutron spectrometer, a drill system, and a mass spectrometer, allowing scientists to make a detailed survey of Titan’s chemical makeup. Dragonfly is scheduled to launch in 2026 and arrive at Titan in 2034.

Video credit: NASA’s Goddard Space Flight Center/Johns Hopkins APL/Dan Gallagher (USRA): Producer, Narrator, Writer/Jonathan North (USRA): Lead Animator/Melissa Trainer (NASA/GSFC): Lead Writer, Scientist/Michael Lentz (USRA): Animator/Ann Parsons (NASA/GSFC): Scientist/Elizabeth Turtle (Johns Hopkins University/APL): Scientist/Aaron E. Lepsch (ADNET): Technical Support/Music: “Clediss” by Thomas Stempfle and Tom Sue, “Downloading Landscapes” by Andrew Michael Britton and David Stephen Goldsmith

Wikipedia dicit:

Astrobiology, formerly known as exobiology, is an interdisciplinary scientific field concerned with the origins, early evolution, distribution, and future of life in the universe. Astrobiology considers the question of whether extraterrestrial life exists, and if it does, how humans can detect it.

Astrobiology makes use of molecular biology, biophysics, biochemistry, chemistry, astronomy, physical cosmology, exoplanetology and geology to investigate the possibility of life on other worlds and help recognize biospheres that might be different from that on Earth. The origin and early evolution of life is an inseparable part of the discipline of astrobiology. Astrobiology concerns itself with interpretation of existing scientific data, and although speculation is entertained to give context, astrobiology concerns itself primarily with hypotheses that fit firmly into existing scientific theories.

This interdisciplinary field encompasses research on the origin of planetary systems, origins of organic compounds in space, rock-water-carbon interactions, abiogenesis on Earth, planetary habitability, research on biosignatures for life detection, and studies on the potential for life to adapt to challenges on Earth and in outer space.

Video credit: NASA

NASA dicit:

Preparing to explore the surface of the Moon goes well beyond designing and building safe spacecraft and spacesuits. NASA also has to ensure the surface vehicles and suits have the mobility required to do science, and that astronauts have the tools they need to identify and scoop up rock and soil samples. Additionally, NASA astronauts are trained in geology, spending countless hours practicing doing science at locations on Earth that resemble regions they might see on the Moon. All this is done in an effort to establish a long-term presence on the Moon and to help answer some outstanding science questions about the history of Earth and of the solar system.

Video credit: NASA’s Goddard Space Flight Center/James Tralie (ADNET): Lead Producer, Lead Editor/Lonnie Shekhtman (ADNET): Lead Writer/Kelsey Young (NASA/GSFC): Scientist/Trevor Graff (Jacobs Technology): Scientist/Aaron E. Lepsch (ADNET): Technical Support/”Saana” and “Seasons” by Torsti Juhani Spoof from Universal Production Music

Wikipedia dicit:

A near-Earth object (NEO) is any small Solar System body whose orbit brings it to proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). If a NEO’s orbit crosses the Earth’s, and the object is larger than 140 meters (460 ft) across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets.

There are over 20,000 known near-Earth asteroids (NEAs), over a hundred short-period near-Earth comets (NECs), and a number of solar-orbiting spacecraft and meteoroids large enough to be tracked in space before striking the Earth. It is now widely accepted that collisions in the past have had a significant role in shaping the geological and biological history of the Earth. NEOs have become of increased interest since the 1980s because of greater awareness of the potential danger. Asteroids as small as 20 m can damage the local environment and populations. Larger asteroids penetrate the atmosphere to the surface of the Earth, producing craters if they impact a continent or tsunamis if they impact sea. Asteroid impact avoidance by deflection is possible in principle, and methods of mitigation are being researched.

Two scales, the Torino scale and the more complex Palermo scale, rate a risk based on how probable the orbit calculations of an identified NEO make an Earth impact and on how bad the consequences of such an impact would be. Some NEOs have had temporarily positive Torino or Palermo scale ratings after their discovery, but as of March 2018, more precise calculations based on longer observation arcs led in all cases to a reduction of the rating to or below 0.

Since 1998, the United States, the European Union, and other nations are scanning the sky for NEOs in an effort called Spaceguard. The initial US Congress mandate to NASA was to catalog at least 90% of NEOs that are at least 1 kilometre (0.62 mi) in diameter, which could cause a global catastrophe,and had been met by 2011. In later years, the survey effort has been expanded to smaller objects which have the potential for large-scale, though not global, damage.

Video credit: NASA

NASA dicit:

Measurements from NASAs Transiting Exoplanet Survey Satellite (TESS) have enabled astronomers to greatly improve their understanding of the bizarre environment of KELT-9 b, one of the hottest planets known. Located about 670 light-years away in the constellation Cygnus, KELT-9 b was discovered in 2017 because the planet passed in front of its star for a part of each orbit, an event called a transit. Transits regularly dim the stars light by a small but detectable amount.

Between July 18 and Sept. 11, 2019, as part of the mission’s yearlong campaign to observe the northern sky, TESS observed 27 transits of KELT-9 b, and these observations allowed the team to model the systems unusual star and its impact on the planet. KELT-9 b is a gas giant world about 1.8 times bigger than Jupiter, with 2.9 times its mass. Tidal forces have locked its rotation so the same side always faces its star. The planet swings around its star in just 36 hours on an orbit that carries it almost directly above both of the star’s poles.

The close orbit means the planet’s dayside temperature is around 7,800 degrees Fahrenheit (4,300 C), hotter than the surfaces of some stars. This intense heating also causes the planets atmosphere to stream away into space.

Its odd host star is about twice the size of the Sun and averages about 56 percent hotter. But it spins 38 times faster than the Sun, completing a full rotation in just 16 hours. Its rapid spin distorts the stars shape, flattening it at the poles and widening its midsection. This causes the stars poles to heat up and brighten while its equatorial region cools and dims, a phenomenon called gravity darkening. The result is a temperature difference across the stars surface of almost 1,500 F (800 C).

With each orbit, KELT-9 b twice experiences the full range of stellar temperatures, producing what amounts to a peculiar seasonal sequence. The planet experiences summer when it swings over each hot pole and winter when it passes over the stars cooler midsection. So KELT-9 b experiences two summers and two winters every year, with each season about nine hours.

KELT-9 b begins its transit near the star’s bright poles, and then blocks less and less light as it travels over the star’s dimmer equator. This asymmetry provides clues to the temperature and brightness changes across the stars surface, and they permitted the team to reconstruct the stars out-of-round shape, how its oriented in space, its range of surface temperatures, and other factors impacting the planet.

Video credit: NASA Goddard