OrbitalHub

NASA dixit:

“On Mars, wind rules. Wind has been shaping the Red Planet’s landscapes for billions of years and continues to do so today. Studies using both a NASA orbiter and a rover reveal its effects on scales grand to tiny on the strangely structured landscapes within Gale Crater.

NASA’s Curiosity Mars rover, on the lower slope of Mount Sharp — a layered mountain inside the crater — has begun a second campaign of investigating active sand dunes on the mountain’s northwestern flank. The rover also has been observing whirlwinds carrying dust and checking how far the wind moves grains of sand in a single day’s time.

Gale Crater observations by NASA’s Mars Reconnaissance Orbiter have confirmed long-term patterns and rates of wind erosion that help explain the oddity of having a layered mountain in the middle of an impact crater.

“The orbiter perspective gives us the bigger picture — on all sides of Mount Sharp and the regional context for Gale Crater. We combine that with the local detail and ground-truth we get from the rover,” said Mackenzie Day of the University of Texas, Austin, lead author of a research report in the journal Icarus about wind’s dominant role at Gale.

The combined observations show that wind patterns in the crater today differ from when winds from the north removed the material that once filled the space between Mount Sharp and the crater rim. Now, Mount Sharp itself has become a major factor in determining local wind directions. Wind shaped the mountain; now the mountain shapes the wind.

The Martian atmosphere is about a hundred times thinner than Earth’s, so winds on Mars exert much less force than winds on Earth. Time is the factor that makes Martian winds so dominant in shaping the landscape. Most forces that shape Earth’s landscapes — water that erodes and moves sediments, tectonic activity that builds mountains and recycles the planet’s crust, active volcanism — haven’t influenced Mars much for billions of years. Sand transported by wind, even if infrequent, can whittle away Martian landscapes over that much time.”

Video credit: NASA Jet Propulsion Laboratory

NASA dixit:

“July 27, 2009. The novel illumination geometry created around the time of Saturn’s August 2009 equinox allows moons orbiting in or near the plane of Saturn’s equatorial rings to cast shadows onto the rings. These scenes are possible only during the few months before and after Saturn’s equinox, which occurs only once in about 15 Earth years.

Pan (28 kilometers, or 17 miles across) orbits in the Encke Gap. This view looks toward the unilluminated side of the rings from about 34 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 839,000 kilometers (521,000 miles) from Pan and at a Sun-Pan-spacecraft, or phase, angle of 74 degrees. Image scale is 5 kilometers (3 miles) per pixel.”

“After almost 20 years in space, NASA’s Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale. Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn’s moon Titan, Cassini will leap over the planet’s icy rings and begin a series of 22 weekly dives between the planet and the rings.

No other mission has ever explored this unique region. What we learn from these final orbits will help to improve our understanding of how giant planets – and planetary systems everywhere – form and evolve.

On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.

Cassini’s Grand Finale is about so much more than the spacecraft’s final dive into Saturn. That dramatic event is the capstone of six months of daring exploration and scientific discovery. And those six months are the thrilling final chapter in a historic 20-year journey.”

Image credit: NASA

ESA dixit:

“Space debris – a journey to Earth takes the audience on a journey from the outer solar system back to our home planet. The objects encountered along the way are man made. Originally designed to explore the universe, these are now a challenge for modern space flight. An estimated number of 700,000 objects larger than 1 cm and 170 million objects larger than 1 mm are expected to reside in Earth orbits.

The video gives a closer look at the different regions used for space flight and explains how mitigation and removal measures could preserve future usage of these orbits.”

Video credit: ESA/ID&Sense/ONiRiXEL, CC BY-SA 3.0 IGO

NASA dixit:

“February 12, 2009. Wendy Darling famously helped Peter Pan catch his shadow, and now Cassini captures the shadow of another Pan: Saturn’s 30-kilometer (19-mile) wide moon inhabiting the Encke Gap. In the center of this image, the shadow of Pan is a short streak thrown over the edge of the A ring where Pan travels its path through the Encke Gap.

One of the happy results of Saturn’s 29-year revolution around the sun is the changing elevation of the sun seen from the planet, and the changing elevation of the shadows of the rings and moons that the sun’s apparent motion brings. As Saturn approaches equinox, the angle at which the ringplane is inclined away from the sun will continue to decrease until August 2009, when equinox will bring about an alignment of the plane containing the rings with the rays of the sun. Only around the time of equinox is a moon’s shadow cast on the rings rather than the planet. Between now and equinox in August, the shadows cast by the moons on the rings will grow longer with time.

Cassini scientists planned a series of observations to chronicle these sights, knowing that the resulting images could hold valuable information about vertical displacements in the rings and the orbital inclinations of the shadow-casting moons. These planned images of course hold another reward: the simple but spectacular depiction of the path of sunlight across the solar system.

The image was taken in visible light with NASA’s Cassini spacecraft narrow-angle camera. This view looks toward the un-illuminated side of the rings from about 55 degrees above the ringplane. The view was obtained at a distance of approximately 997,000 kilometers (619,000 miles) from Pan and at a sun-Pan-spacecraft, or phase, angle of 112 degrees. Image scale is 6 kilometers (4 miles) per pixel.”

“After almost 20 years in space, NASA’s Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale. Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn’s moon Titan, Cassini will leap over the planet’s icy rings and begin a series of 22 weekly dives between the planet and the rings.

No other mission has ever explored this unique region. What we learn from these final orbits will help to improve our understanding of how giant planets – and planetary systems everywhere – form and evolve.

On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.

Cassini’s Grand Finale is about so much more than the spacecraft’s final dive into Saturn. That dramatic event is the capstone of six months of daring exploration and scientific discovery. And those six months are the thrilling final chapter in a historic 20-year journey.”

Image credit: NASA

NASA Goddard dixit:

“From long, tapered jets to massive explosions of solar material and energy, eruptions on the sun come in many shapes and sizes. Since they erupt at such vastly different scales, jets and the massive clouds — called coronal mass ejections, or CMEs — were previously thought to be driven by different processes.

Scientists from Durham University in the United Kingdom and NASA now propose that a universal mechanism can explain the whole spectrum of solar eruptions. They used 3-D computer simulations to demonstrate that a variety of eruptions can theoretically be thought of as the same kind of event, only in different sizes and manifested in different ways.

The study was motivated by high-resolution observations of filaments from NASA’s Solar Dynamics Observatory, or SDO, and the joint Japan Aerospace Exploration Agency/NASA Hinode satellite. Filaments are dark, serpentine structures that are suspended above the sun’s surface and consist of dense, cold solar material. The onset of CME eruptions had long been known to be associated with filaments, but improved observations have recently shown that jets have similar filament-like structures before eruption too. So the scientists set out to see if they could get their computer simulations to link filaments to jet eruptions as well.

Solar scientists can use computer models like this to help round out their understanding of the observations they see through space telescopes. The models can be used to test different theories, essentially creating simulated experiments that cannot, of course, be performed on an actual star in real life.

The scientists call their proposed mechanism for how these filaments lead to eruptions the breakout model, for the way the stressed filament pushes relentlessly at — and ultimately breaks through — its magnetic restraints into space. They previously used this model to describe CMEs; in this study, the scientists adapted the model to smaller events and were able to reproduce jets in the computer simulations that match the SDO and Hinode observations. Such simulations provide additional confirmation to support the observations that first suggested coronal jets and CMEs are caused in the same way.”

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

Copenhagen Suborbitals dixit:

“In the summer of 2016, Copenhagen Suborbitals launched one of the most advanced liquid fueled rockets built by a team of volunteer amateurs. Follow the team close up during final preparations for the launch and during the launch of the Nexø I rocket. Enjoy.

Copenhagen Suborbitals is the world’s only manned, amateur space program, 100% crowdfunded and nonprofit. In the future, one of us will fly to space on a home built rocket.”

Video credit: Copenhagen Suborbitals