OrbitalHub

Wikipedia dicit:

ICESat-2 (Ice, Cloud, and land Elevation Satellite 2), part of NASA’s Earth Observing System, is a satellite mission for measuring ice sheet elevation and sea ice thickness, as well as land topography, vegetation characteristics, and clouds. ICESat-2, a follow-on to the ICESat mission, was launched on 15 September 2018 from Vandenberg Air Force Base in California, into a near-circular, near-polar orbit with an altitude of approximately 496 km (308 mi). It was designed to operate for three years and carry enough propellant for seven years. The satellite orbits Earth at a speed of 6.9 kilometers per second (4.3 mi/s).

The ICESat-2 mission is designed to provide elevation data needed to determine ice sheet mass balance as well as vegetation canopy information. It will provide topography measurements of cities, lakes and reservoirs, oceans and land surfaces around the globe, in addition to the polar-specific coverage. ICESat-2 also has the ability to detect seafloor topography up to 100 feet (30m) below the surface in clear watered coastal areas. Because the great changes of polar ice cover in global warming are not quantified, one of the main purposes of ICESat-2 is measuring the changing of the elevation of ice sheets by its laser system and lidar to quantify the influence of melting ice sheet in sea-level raising. Additionally, the high accuracy of multiple pulses allows collecting measurement of the heights of sea ice to analyze its change rate during the time.

The ICESat-2 spacecraft was built and tested by Northrop Grumman Innovation Systems in Gilbert, Arizona, while the on board instrument, ATLAS, was built and managed by Goddard Space Flight Center in Greenbelt, Maryland. The ATLAS instrument was designed and built by the center, and the bus was built by and integrated with the instrument by Orbital Sciences (later Orbital ATK). Orbital ATK, which was a global leader in aerospace and defense technologies, was acquired by the Northrop Grumman Corporation on June 6, 2018. The satellite was launched on a Delta II rocket provided by United Launch Alliance. This was the last launch of the Delta II rocket.

Video credit: Credit: NASA’s Scientific Visualization Studio/Kel Elkins (USRA): Lead Visualizer/Ryan Fitzgibbons (USRA): Lead Producer/Alek A. Petty (University of Maryland): Scientist/Thomas A. Neumann Ph.D. (NASA/GSFC): Scientist/Nathan T. Kurtz (NASA/GSFC): Scientist

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