3-Oct-2019: Chandrayaan-2, CLASS detects charged particles during the mission
Our Sun emits a continuous outflowing stream of electrons and protons into the solar system, called the solar wind. The solar wind plasma which has charged particles embedded in the extended magnetic field of the Sun, moves at speeds of a few hundred km per second. It interacts with solar system bodies including Earth and its moon. Since the Earth has a global magnetic field, it obstructs the solar wind plasma and this interaction results in the formation of a magnetic envelope around Earth, called the magnetosphere.
The Earth’s magnetosphere is compressed into a region approximately three to four times the Earth radius (~22000 km above the surface) on the side facing the Sun, but is stretched into a long tail (geotail) on the opposite side that goes beyond the orbit of Moon. Approximately, once every 29 days, Moon traverses the geotail for about 6 days centered around full moon. Thus Chandrayaan-2 also crosses this geotail and its instruments can study properties of geotail at a few hundred thousand kilometers from Earth.
The CLASS instrument on Chandrayaan-2 is designed to detect direct signatures of elements present in the lunar soil. This is best observed when a solar flare on the Sun provides a rich source of x-rays to illuminate the lunar surface; secondary x-ray emission resulting from this can be detected by CLASS to directly detect the presence of key elements like Na, Ca, Al, Si, Ti and Fe.
While this kind of “flash photography” requires one to await an opportune time for Sun to be active, CLASS in its first few days of observation, could detect charged particles and its intensity variations during its first passage through the geotail during Sept.
More detailed studies in future along with observations from other space missions, will enable a multi-point study, essential to unravel the “dance of electrons to the music of magnetic fields” around Moon.
23-Aug-2019: What's Mars Solar Conjunction, and Why Does It Matter?
NASA spacecraft at Mars are going to be on their own for a few weeks when the Sun comes between Mars and Earth, interrupting communications.
Mars and Earth will be on opposite sides of the Sun, a period known as Mars solar conjunction. The Sun expels hot, ionized gas from its corona, which extends far into space. During solar conjunction, this gas can interfere with radio signals when engineers try to communicate with spacecraft at Mars, corrupting commands and resulting in unexpected behavior from our deep space explorers. To be safe, engineers hold off on sending commands when Mars disappears far enough behind the Sun's corona that there's increased risk of radio interference.
Solar conjunction occurs every two years. This time, the hold on issuing commands - called a "command moratorium" - will run from Aug. 28 to Sept. 7, 2019. Some missions will have stopped commanding their spacecraft earlier in preparation for the moratorium.
Although some instruments aboard spacecraft - especially cameras that generate large amounts of data - will be inactive, all of NASA's Mars spacecraft will continue their science; they'll just have much simpler "to-do" lists than they normally would carry out.
On the surface of Mars, the Curiosity rover will stop driving, while the InSight lander won't move its robotic arm. Above Mars, both the Odyssey orbiter and the Mars Reconnaissance Orbiter will continue collecting data from Curiosity and InSight for return to Earth. However, only Odyssey will attempt to relay that data to Earth before conjunction ends. Meantime, another orbiter, MAVEN, will continue to collect its own science data but won't support any relay operations during this time.
All of this means that there will be a temporary pause in the stream of raw images available from Curiosity, InSight and the other Mars missions. Mars solar conjunction impacts operations of all spacecraft currently at Mars, not just NASA's.
Once conjunction is over, the spacecraft will beam the data they've collected to NASA's Deep Space Network, a system of massive Earth-based radio antennas managed by JPL. Engineers will spend about a week downloading the information before normal spacecraft operations resume.
If the teams monitoring these missions determine any of the collected science data are corrupted, they can usually have that data retransmitted after the moratorium ends on Sept. 7.
26-Feb-2019: NASA Selects Mission to Study Space Weather from Space Station
NASA has selected a new mission that will help scientists understand and, ultimately, forecast the vast space weather system around our planet. Space weather is important because it can have profound impacts – affecting technology and astronauts in space, disrupting radio communications and, at its most severe, overwhelming power grids.
The new experiment will, for the first time, obtain global observations of an important driver of space weather in a dynamic region of Earth’s upper atmosphere that can cause interference with radio and GPS communications.
The Atmospheric Waves Experiment (AWE) mission will cost $42 million and is planned to launch in August 2022, attached to the exterior of the Earth-orbiting International Space Station. From its space station perch, AWE will focus on colorful bands of light in Earth’s atmosphere, called airglow, to determine what combination of forces drive space weather in the upper atmosphere.
Researchers once thought that only the Sun’s constant outflow of ultraviolet light and particles, the solar wind, could affect the region. However, recently they have learned that solar variability is not enough to drive the changes observed, and Earth’s weather also must be having an effect. To help unravel that connection, AWE will investigate how waves in the lower atmosphere, caused by variations in the densities of different packets of air, impact the upper atmosphere.
AWE is a Mission of Opportunity under NASA’s Heliophysics Explorers Program, which conducts focused scientific research and develops instrumentation to fill the scientific gaps between the agency’s larger missions. Since the 1958 launch of NASA’s first satellite Explorer 1, which discovered Earth’s radiation belts, the Explorers Program has supported more than 90 missions. The Uhuru and Cosmic Background Explorer (COBE) missions led to Nobel prizes for their investigators.
The Explorers Program seeks innovative ideas for small and cost-constrained missions that can help unravel the mysteries of the universe and explore our place in it. This mission absolutely meets that standard with a creative and cost-effective mission to solve mysteries about Earth’s upper atmosphere.
AWE was selected for development based on its potential science value and the feasibility of its development plans.