“NASA’s GPM Core Observatory satellite captured an image of Super Typhoon Yutu when it flew over the powerful storm just as the center was striking the central Northern Mariana Islands north of Guam. Early Thursday, October 25 local time, Super Typhoon Yutu crossed over the U.S. Commonwealth of the Northern Mariana Islands. It was the equivalent of a Category 5 hurricane. The National Weather Service in Guam said it was the strongest storm to hit any part of the U.S. this year.
The Global Precipitation Measurement mission or GPM core satellite, which is managed by both NASA and the Japan Aerospace Exploration Agency, JAXA analyzed Yutu on October 24 at 11:07 a.m. EDT (1507 UTC)/ 1:07 a.m. Guam Time, October 25. GPM estimated rain rates within Super Typhoon Yutu fusing data from two instruments aboard: the GPM Dual-frequency Precipitation Radar or DPR, which covered the inner part of the storm, and the GPM Microwave Imager or GMI that analyzed the outer swath, just as the center was passing over the Island of Tinian.”
“The New Shepard reusable launch system is a vertical-takeoff, vertical-landing (VTVL), suborbital crewed rocket that is being developed by Blue Origin as a commercial system for suborbital space tourism. Blue Origin is owned and led by Amazon.com founder and businessman Jeff Bezos and aerospace engineer Rob Meyerson.
The name New Shepard makes reference to the first American astronaut in space, Alan Shepard, one of the original NASA Mercury Seven astronauts, who ascended to space on a suborbital trajectory similar to that planned for New Shepard. Prototype engine and vehicle flights began in 2006, while full-scale engine development started in the early 2010s and was complete by 2015. Uncrewed flight testing of the complete New Shepard vehicle (propulsion module and space capsule) began in 2015. Flights with test passengers were planned for 2018, with commercial passenger flights initially planned to begin in 2018 as well.
On 23 November 2015, after reaching 100.5 km (62.4 mi) altitude (outer space), the New Shepard booster successfully performed a powered vertical soft landing, the first time a booster rocket had returned from space to make a successful vertical landing. The test program continued in 2016 and 2017 with four additional test flights made with the same vehicle (NS2) in 2016 and the first test flight of the new NS3 vehicle made in 2017.”
“As of October 2016, all methods of landing on Mars have required an aeroshell and parachute sequence for Mars atmospheric entry and descent, but after that there are three choices. A stationary lander can drop from the parachute back shell and ride retrorockets all the way down, but a rover cannot be burdened with rockets that serve no purpose after touchdown.
One method (for lighter rovers) is to enclose the rover in a tetrahedronal structure which in turn is enclosed in airbags. After the aeroshell drops off, the tetrahedron is lowered clear of the parachute back shell on a lanyard so that the airbags can inflate. Retrorockets on the back shell can slow descent. When it nears the ground, the tetrahedron is released to drop to the ground, using the airbags as shock absorbers. When it has come to rest, the tetrahedron opens to expose the rover.
If a rover is too heavy to use airbags, the retrorockets can be mounted on a sky crane. The sky crane drops from the parachute back shell and, as it nears the ground, the rover is lowered on a lanyard. When the rover touches ground, it cuts the lanyard so that the sky crane (with its rockets still firing) will crash well away from the rover.
For landers that are even heavier than the Curiosity rover (which required a 4.5 meter (15 feet) diameter aeroshell), engineers are developing a combination rigid-inflatable Low-Density Supersonic Decelerator that could be 8 meters (28 feet) in diameter. It would have to be accompanied by a proportionately larger parachute.”
“This visualization uses a digital 3D model of the Moon built from global elevation maps and image mosaics by NASA’s Lunar Reconnaissance Orbiter mission. It was created to accompany a performance of Claude Debussy’s Clair de Lune by the National Symphony Orchestra Pops, led by conductor Emil de Cou, at the Kennedy Center for the Performing Arts in Washington, DC, on June 1 and 2, 2018, as part of a celebration of NASA’s 60th anniversary.
The visuals were composed like a nature documentary, with clean cuts and a mostly stationary virtual camera. The viewer follows the Sun throughout a lunar day, seeing sunrises and then sunsets over prominent features on the Moon. The sprawling ray system surrounding Copernicus crater, for example, is revealed beneath receding shadows at sunrise and later slips back into darkness as night encroaches.”
“The Dawn mission was designed to study two large bodies in the asteroid belt in order to answer questions about the formation of the Solar System, as well as to test the performance of its ion drive in deep space. Ceres and Vesta were chosen as two contrasting protoplanets, the first one apparently “wet” (i.e. icy and cold) and the other “dry” (i.e. rocky), whose accretion was terminated by the formation of Jupiter. The two bodies provide a bridge in scientific understanding between the formation of rocky planets and the icy bodies of the Solar System, and under what conditions a rocky planet can hold water.
The International Astronomical Union (IAU) adopted a new definition of planet on August 24, 2006, which introduced the term “dwarf planet” for ellipsoidal worlds that were too small to qualify for planetary status by “clearing their orbital neighborhood” of other orbiting matter. Dawn is the first mission to study a dwarf planet, arriving at Ceres a few months before the arrival of the New Horizons probe at Pluto in July 2015.
Ceres comprises a third of the total mass of the asteroid belt. Its spectral characteristics suggest a composition similar to that of a water-rich carbonaceous chondrite. Vesta, a smaller, water-poor achondritic asteroid comprising a tenth of the mass of the asteroid belt, has experienced significant heating and differentiation. It shows signs of a metallic core, a Mars-like density and lunar-like basaltic flows.
Available evidence indicates that both bodies formed very early in the history of the Solar System, thereby retaining a record of events and processes from the time of the formation of the terrestrial planets. Radionuclide dating of pieces of meteorites thought to come from Vesta suggests that Vesta differentiated quickly, in three million years or less. Thermal evolution studies suggest that Ceres must have formed some time later, more than three million years after the formation of CAIs (the oldest known objects of Solar System origin).
Moreover, Vesta appears to be the source of many smaller objects in the Solar System. Most (but not all) V-type near-Earth asteroids, and some outer main-belt asteroids, have spectra similar to Vesta, and are thus known as vestoids. Five percent of the meteoritic samples found on Earth, the howardite–eucrite–diogenite (HED) meteorites, are thought to be the result of a collision or collisions with Vesta.
It is thought that Ceres may have a differentiated interior; its oblateness appears too small for an undifferentiated body, which indicates that it consists of a rocky core overlain with an icy mantle. There is a large collection of potential samples from Vesta accessible to scientists, in the form of over 1,400 HED meteorites, giving insight into Vesta geologic history and structure. Vesta is thought to consist of a metallic iron–nickel core, an overlying rocky olivine mantle and crust.”
“The stacked spacecraft will take seven years to position itself to enter Mercury orbit. During this time it will use solar-electric propulsion and nine gravity assists, flying past the Earth and Moon in April 2020, Venus in 2020 and 2021, and six Mercury flybys between 2021 and 2025.
The stacked spacecraft left Earth with an hyperbolic excess velocity of 3.475 km/s (2.159 mi/s). Initially the craft is placed in an orbit similar to that of the Earth. After both the spacecraft and the Earth completed one and a half orbits, it returns to Earth to perform a gravity-assist manoeuvre and is deflected towards Venus. Two consecutive Venus flybys reduce the perihelion nearly to Mercury distance with almost no need for thrust. A sequence of six Mercury flybys will lower the relative velocity to 1.76 km/s (1.09 mi/s). After the fourth Mercury flyby the craft will be in an orbit similar to that of Mercury and will remain in the general vicinity of Mercury. Four final thrust arcs reduce the relative velocity to the point where Mercury will “weakly” capture the spacecraft on 5 December 2025 into polar orbit. Only a small manoeuvre is needed to bring the craft into an orbit around Mercury with an apocentre of 178,000 km. The orbiters then separate and will adjust their orbits using chemical thrusters.”
Subscribe to blog posts using RSS
