OrbitalHub

Wikipedia dicit:

The Solar and Heliospheric Observatory (SOHO) is a spacecraft built by a European industrial consortium led by Matra Marconi Space (now Airbus Defence and Space) that was launched on a Lockheed Martin Atlas II AS launch vehicle on December 2, 1995 to study the Sun. SOHO has also discovered over 3,000 comets. It began normal operations in May 1996. It is a joint project of international cooperation between the European Space Agency (ESA) and NASA. Originally planned as a two-year mission, SOHO continues to operate after over 25 years in space: the mission is extended until the end of 2020 with a likely extension until 2022.

In addition to its scientific mission, it is a main source of near-real-time solar data for space weather prediction. Along with Wind, ACE and DSCOVR, SOHO is one of four spacecraft in the vicinity of the Earth–Sun L1 point, a point of gravitational balance located approximately 0.99 astronomical unit (AU)s from the Sun and 0.01 AU from the Earth. In addition to its scientific contributions, SOHO is distinguished by being the first three-axis-stabilized spacecraft to use its reaction wheels as a kind of virtual gyroscope; the technique was adopted after an on-board emergency in 1998 that nearly resulted in the loss of the spacecraft.

Video credit: NASA Goddard

Wikipedia dicit:

In 2019, NASA’s James Webb Space Telescope celebrated the full mechanical and electrical assembly of the world’s largest, most powerful space science observatory ever built. Webb’s two halves have been physically put together and its wiring harnesses and electrical interfaces have been connected.

Following assembly, the Webb team moved on to successfully send deployment and tensioning commands to all five layers of its sunshield, which is designed to protect the observatory’s mirrors and scientific instruments from light and heat, primarily from the Sun.

Ensuring mission success for an observatory of this scale and complexity is a challenging endeavor. All of the telescope’s major components have been tested individually through simulated environments they would encounter during launch, and while orbiting a million miles away from Earth. Now that Webb is fully assembled, it must meet rigorous observatory-level standards. The complete spacecraft reacts and performs differently to testing environments than when its components are tested individually.

Following Webb’s successful sunshield deployment and tensioning test, team members have nearly finished the long process of perfectly folding the sunshield back into its stowed position for flight, which occupies a much smaller space than when it is fully deployed. Then, the observatory will be subjected to comprehensive electrical tests and one more set of mechanical tests that emulate the launch acoustic and vibration environment, followed by one final deployment and stowing cycle on the ground, before its flight into space. The James Webb Space Telescope is scheduled to launch in 2021.

Video credit: NASA’s Goddard Space Flight Center, Greenbelt, Md./Aaron E. Lepsch (ADNET): Technical Support/Michael McClare (KBRwyle): Videographer/Sophia Roberts (AIMM): Videographer/Michael P. Menzel (AIMM): Video Editor

NASA dicit:

A new study of observations from NASA’s Fermi Gamma-ray Space Telescope has discovered a faint but sprawling glow around a nearby pulsar. If visible to the human eye, this gamma-ray halo would appear larger in the sky than the famed Big Dipper star pattern. The halo suggests this same pulsar could be responsible for a decade-long puzzle about one type of cosmic particle arriving from beyond the solar system that is unusually abundant near Earth — positrons, the antimatter version of electrons.

A neutron star is the crushed core left behind when a star much more massive than the Sun runs out of fuel, collapses under its own weight and explodes as a supernova. We see some neutron stars as pulsars, rapidly spinning objects emitting beams of radio waves, light, X-rays and gamma rays that, much like a lighthouse, regularly sweep across our line of sight from Earth.

Geminga (pronounced geh-MING-a) is among the brightest pulsars at gamma-ray energies. To study its halo, scientists had to subtract out all other sources of gamma rays, including diffuse light produced by cosmic ray collisions with interstellar gas clouds. Ten different models of interstellar emission were evaluated. What remained when these sources were removed was a vast, oblong glow spanning some 20 degrees — about 40 times the apparent size of a full Moon — at an energy of 10 billion electron volts (GeV), and even larger at lower energies.

The team determined that Geminga alone could be responsible for as much as 20% of the high-energy positrons seen by other space experiments. Extrapolating this to the cumulative emission of positrons from all pulsars in our galaxy, the scientists say it’s clear that pulsars remain the best explanation for the observed excess of positrons.

Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (USRA): Producer/Francis Reddy (University of Maryland College Park): Science writer/Mattia Di Mauro (Catholic University of America): Visualizer/Mattia Di Mauro (Catholic University of America): Scientist

NASA dicit:

NASA’s Wide Field Infrared Survey Telescope, WFIRST, will capture the equivalent of 100 high-resolution Hubble images in a single shot, imaging large areas of the sky 1,000 times faster than Hubble. In several months, WFIRST could survey as much of the sky in near-infrared light—in just as much detail—as Hubble has over its entire three decades.

Although WFIRST has not yet opened its wide, keen eyes on the universe, astronomers are already running simulations to demonstrate what it will be able to see and plan their observations. The simulated image of a portion of our neighboring galaxy Andromeda (M31) provides a preview of the vast expanse and fine detail that can be covered with just a single pointing of WFIRST. Using information gleaned from hundreds of Hubble observations, the simulated image covers a swath roughly 34,000 light-years across, showcasing the red and infrared light of more than 50 million individual stars detectable with WFIRST.

While it may appear to be a somewhat haphazard arrangement of 18 separate images, the simulation actually represents a single shot. Eighteen square detectors, 16-megapixels each, make up WFIRST’s Wide Field Instrument (WFI) and give the telescope its unique window into space. With each pointing, WFIRST will cover an area roughly 1â…“ times that of the full Moon. By comparison, each individual infrared Hubble image covers an area less than 1% of the full Moon.

WFIRST is designed to collect the big data needed to tackle essential questions across a wide range of topics, including dark energy, exoplanets, and general astrophysics spanning from our solar system to the most distant galaxies in the observable universe. Over its 5-year planned lifetime, WFIRST is expected to amass more than 20 petabytes of information on thousands of planets, billions of stars, millions of galaxies, and the fundamental forces that govern the cosmos.

Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (USRA): Lead Producer/Ben Williams (U. Washington, Seattle): Visualizer/Scott Wiessinger (USRA): Narrator

NASA dicit:

In February 2020, NASA’s Solar Dynamics Observatory — SDO — is celebrating its 10th year in space. Over the past decade the spacecraft has kept a constant eye on the Sun, studying how the Sun creates solar activity and drives space weather — the dynamic conditions in space that impact the entire solar system, including Earth.

Since its launch on February 11, 2010, SDO has collected millions of scientific images of our nearest star, giving scientists new insights into its workings. SDO’s measurements of the Sun — from the interior to the atmosphere, magnetic field, and energy output — have greatly contributed to our understanding of our closest star. SDO’s images have also become iconic — if you’ve ever seen a close-up of activity on the Sun, it was likely from an SDO image.

Video credit: NASA’s Goddard Space Flight Center/Scott Wiessinger (USRA): Lead Producer/Mara Johnson-Groh (Wyle Information Systems): Science Writer/Barb Mattson (University of Maryland College Park): Narrator

NASA dicit:

NASA’s Solar Dynamics Observatory (SDO) stares at our sun in high-definition from space. Under the spacecraft’s constant gaze the sun’s invisible magnetic field betrays its presence by bending charged gas, or plasma, into entrancing patterns. In February 2012, SDO captured curious images in which plasma near the sun’s surface appears to swirl like debris in a tornado. But was the plasma really rotating? Some scientists believe the spinning is an illusion caused by a 2-D projection of 3-D motion, while others think it is truly twisting. Newer observations may show more clearly that some of the material is moving toward Earth while some is moving away, pointing to genuine rotation. If that’s the case, bunched magnetic fields at the sun’s surface could be causing the elaborate plasma dance by becoming tangled themselves.

Video credit: NASA’s Goddard Space Flight Center/Visualizer/Animator: Tom Bridgman (GST)/Producers: Michael Starobin (HTSI),Scott Wiessinger (USRA)/Scientists: Yang Su (University of Graz), Todd Hoeksema (Stanford)/Writer: Chris Cesare (USRA)