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Subject: Space Technology

  • 2020 CD3: A mini-moon

     

     

    Astronomers have observed a small object orbiting Earth, which they have dubbed a “mini-moon” or the planet’s “second moon”.

    2020 CD3

    • The mini-moon was discovered by some astronomers at NASA-funded Catalina Sky Survey (CSS) in Arizona.
    • It is actually an asteroid, about the size of a car; its diameter is about 1.9-3.5 m.
    • And unlike our permanent Moon, the mini-moon is temporary; it will eventually break free of Earth’s orbit and go off on its own way.
    • Orbit integrations indicate that this object is temporarily bound to the Earth.
    • 2020 CD3 was captured into Earth’s orbit over three years ago.
    • For CSS, it is only the second such discovery. It previously discovered 2006 RH120, which orbited Earth for some time that year, before it escaped in 2007.

    Where do such moons come from?

    • When an asteroid’s orbit crosses Earth’s orbit, it can sometimes be captured into the latter orbit. This is what happened with 2020 CD3.
    • It is now orbiting at a distance farther from Earth. Such an asteroid is called a Temporarily Captured Object (TCO).
    • The orbit of such objects is unstable. They have to contend with the gravitational influence of our permanent Moon as well as that of the Sun.
    • Once caught in Earth’s orbit, such objects usually remain for a few years before they break free and go into independent orbit around the Sun.

  • NASA’s InSight Mission

     

    It’s now more than a year since NASA’s InSight lander mission touched down on Mars on November 26, 2018. This week, NASA published a report regarding findings on the Mars.

    About InSight Mission

    • The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport mission is a robotic lander designed to study the deep interior of the planet Mars.
    • It is the first mission dedicated to looking deep beneath the Martian surface.
    • Among its science tools are a seismometer for detecting quakes, sensors for gauging wind and air pressure, a magnetometer, and a heat flow probe designed to take the planet’s temperature.
    • The InSight mission is part of NASA’s Discovery Program.
    • It is being supported by a number of European partners, which include France’s Centre National d’Études Spatiales (CNES), the German Aerospace Center (DLR) and the United Kingdom Space Agency (UKSA).

    Key findings of the Mission

    Underground: rumbles

    • Mars trembles more often than expected, but also more mildly.
    • This emerged from readings of the ultra-sensitive seismometer, called the Seismic Experiment for Interior Structure (SEIS).
    • The instrument enables scientists to “hear” multiple trembling events from hundreds to thousands of miles away.
    • Mars doesn’t have tectonic plates like Earth, but it does have volcanically active regions that can cause rumbles.

    The surface: Magnetism

    • Billions of years ago, Mars had a magnetic field.
    • Although it is no longer present, it left behind what NASA describes as “ghosts” – magnetized rocks that are now between 61 m to several km below ground.
    • InSight is equipped with a magnetometer, which has detected magnetic signals.
    • At a Martian site called Homestead hollow, the magnetic signals are 10 times stronger than what was predicted earlier (based on data from orbiting spacecraft).

    In the wind: dust devils

    • InSight measures wind speed, direction and air pressure nearly continuously.
    • Weather sensors have detected thousands of passing whirlwinds, which are called dust devils when they pick up grit and become visible.
    • The site has more whirlwinds than any other place where a landing has been made on Mars while carrying weather sensors.
    • Despite all that activity in the wind and frequent imaging, InSight’s cameras have yet to see dust devils. But SEIS can feel these whirlwinds pulling on the surface.

    The core: still to come

    • InSight has two radios. One is for regularly sending and receiving data. The other radio, which is more powerful, is designed to measure the “wobble” of Mars as it spins.
    • This X-band radio, also known as the Rotation and Interior Structure Experiment (RISE), can eventually reveal whether the planet’s core is solid or liquid.
    • A solid core would cause Mars to wobble less than a liquid one would.
    • This first year of data is just a start, NASA said in the statement. When it is two years on Earth, Mars will have completed one year.

  • Habitable-zone Planet Finder (HPF)

     

    At 100 light-years from Earth, a low-mass star was sending signals in a pattern that suggested that an exoplanet was orbiting the star confirmed the Habitable-zone Planet Finder (HPF).

    Habitable-zone Planet Finder

    • NASA’s Kepler mission observed a dip in the host star’s light, suggesting that the planet was crossing in front of the star during its orbit.
    • To confirm, researchers turned to an instrument called Habitable-zone Planet Finder (HPF). It has confirmed that there is indeed an exoplanet.
    • HPF is an astronomical spectrograph, built by Penn State University scientists, and recently installed on the 10m Hobby-Eberly Telescope at McDonald Observatory in Texas.
    • The instrument is designed to detect and characterize planets in the habitable zone — the region around the star where a planet could sustain liquid water on its surface — around nearby low-mass stars.
    • The newly confirmed planet, called G 9-40b, is the first one validated by HPF. It is about twice the size of Earth and orbits its star once every six Earth-days.

    How it works

    • A spectrograph is an instrument that splits light into its component wavelengths.
    • Scientists then measure the properties of light over a specific portion of the spectrum and draw conclusions on what is responsible for the trends they observe.

    Why need HPF?

    • Kepler’s observations alone were not enough to confirm a planet. It was possible that a close stellar companion was responsible for the dip in the star’s light.
    • Precision spectroscopic observations from HPF ruled out this possibility.
    • Shooting a high-power laser into the air, researchers generated a “laser guide star”, and subsequent observations found no evidence of blending of light or other stellar companions.
    • Finally, using HPF, an analysis of a set of radial velocities helped provide estimates for the planet’s mass.

  • Aditya L1 Mission

     

    NASA’s Parker Solar Probe launched on August 12, 2018 has completed its fourth close approach — called perihelion very recently, whizzing past at about 3.93 lakh km/h, at a distance of only 18.6 million km from the Sun’s surface.

    Aditya L1: Exciting ahead

    • The ISRO is preparing to send its first scientific expedition to study the Sun.
    • Named Aditya-L1, the mission, expected to be launched early next year, will observe the Sun from a close distance, and try to obtain information about its atmosphere and magnetic field.
    • ISRO categorizes Aditya L1 as a 400 kg-class satellite that will be launched using the Polar Satellite Launch Vehicle (PSLV) in XL configuration.
    • The space-based observatory will have seven payloads (instruments) on board to study the Sun’s corona, solar emissions, solar winds and flares, and Coronal Mass Ejections (CMEs), and will carry out round-the-clock imaging of the Sun.
    • Aditya L1 will be ISRO’s second space-based astronomy mission after AstroSat, which was launched in September 2015.

    What is L1?

    • L1 refers to Lagrangian/Lagrange Point 1, one of five points in the orbital plane of the Earth-Sun system.
    • Lagrange Points, named after Italian-French mathematician Josephy-Louis Lagrange, are positions in space where the gravitational forces of a two-body system (like the Sun and the Earth) produce enhanced regions of attraction and repulsion.
    • These can be used by spacecraft to reduce fuel consumption needed to remain in position.
    • The L1 point is home to the Solar and Heliospheric Observatory Satellite (SOHO), an international collaboration project of NASA and the European Space Agency (ESA).
    • The L1 point is about 1.5 million km from Earth, or about one-hundredth of the way to the Sun.

    But why is studying the Sun important?

    • Every planet, including Earth and the exoplanets beyond the Solar System, evolves — and this evolution is governed by its parent star.
    • The solar weather and environment, which is determined by the processes taking place inside and around the sun, affects the weather of the entire system.
    • Variations in this weather can change the orbits of satellites or shorten their lives, interfere with or damage onboard electronics, and cause power blackouts and other disturbances on Earth.
    • Knowledge of solar events is key to understanding space weather.
    • To learn about and track Earth-directed storms, and to predict their impact, continuous solar observations are needed.
    • Every storm that emerges from the Sun and heads towards Earth passes through L1, and a satellite placed in the halo orbit around L1 of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/eclipses.

    Why are solar missions challenging?

    • What makes a solar mission challenging is the distance of the Sun from Earth (about 149 million km on average, compared to the only 3.84 lakh km to the Moon).
    • More importantly the super hot temperatures and radiations in the solar atmosphere make it difficult to study.
    • NASA’s Parker Solar Probe has already gone far closer — but it will be looking away from the Sun.
    • The earlier Helios 2 solar probe, a joint venture between NASA and space agency of erstwhile West Germany, went within 43 million km of the Sun’s surface in 1976.

    Problem of Heat

    • The Parker Solar Probe’s January 29 flyby was the closest the spacecraft has gone to the Sun in its planned seven-year journey so far.
    • Computer modelling estimates show that the temperature on the Sun-facing side of the probe’s heat shield, the Thermal Protection System, reached 612 degrees Celsius, even as the spacecraft and instruments behind the shield remained at about 30°C, NASA said.
    • During the spacecraft’s three closest perihelia in 2024-25, the TPS will see temperatures around 1370°C.

    Hurdles for Aditya L1

    • It will stay much farther away, and the heat is not expected to be a major concern for the instruments on board. But there are other challenges.
    • Many of the instruments and their components for this mission are being manufactured for the first time in the country, presenting as much of a challenge as an opportunity for India’s scientific, engineering, and space communities.
    • One such component is the highly polished mirrors which would be mounted on the space-based telescope.
    • Due to the risks involved, payloads in earlier ISRO missions have largely remained stationary in space; however, Aditya L1 will have some moving components, scientists said.

  • Supergiant star ‘Betelgeuse’

     

    Using the European Space Organization’s (ESO) Very Large Telescope (VLT), astronomers have noticed the unprecedented dimming of Betelgeuse.

     Betelgeuse

    • It is a red supergiant star (over 20 times bigger than the Sun) in the constellation Orion.
    • Along with the dimming, the star’s shape has been changing as well, as per recent photographs of the star taken using the VISIR instrument on the VLT.
    • Instead of appearing round, the star now appears to be “squashed into an ova”.

    Why is it significant?

    • Betelgeuse was born as a supermassive star millions of years ago and has been “dramatically” and “mysteriously” dimming for the last six months.
    • While Betelgeuse’s behaviour is out of the ordinary, it doesn’t mean that an eruption is imminent since astronomers predict the star to blast sometime (supernova explosion, which is the largest explosion to take place in space) in the next 100,000 years or so.

  • Discovery Program investigations by NASA

    NASA announced it has selected four Discovery Program investigations to develop concept studies for possible new missions.

    What are the new missions?

    • Two proposals are for trips to Venus, and one each is for Jupiter’s moon Io and Neptune’s moon Triton.
    • After the concept studies are completed in nine months, some missions ultimately may not be chosen to move forward.

    DAVINCI+

    • DAVINCI+ stands for Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus.
    • This will analyse Venus’s atmosphere to understand how it was formed and evolved, and if it ever had an ocean.
    • This will advance understanding of the formation of terrestrial planets.

    IVO

    • Io Volcano Observer is a proposal to explore Jupiter’s moon Io, which is extremely volcanically active.
    • This will try to find out how tidal forces shape planetary bodies.
    • The findings could further knowledge about the formation and evolution of rocky, terrestrial bodies and icy ocean worlds in the Solar System.

    TRIDENT

    This aims to explore Neptune’s icy moon, Triton, so that scientists can understand the development of habitable worlds in the Solar System.

    VERITAS

    Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy will aim to map Venus’s surface to find out why Venus developed so differently from Earth.

  • The ‘Pale Blue Dot’

     

    The Jet Propulsion Laboratory of the NASA published a new version of the image of Pale Blue Dot.

    Pale Blue Dot

    • The ‘Pale Blue Dot’ is one of the most iconic images in the history of astronomy.
    • It shows Earth as a single bright blue pixel in empty space within a strand of sun rays, some of which are scattering from and enlightening the planet.
    • The original image was taken by the Voyager 1 mission spacecraft on February 14, 1990 when it was just beyond Saturn.
    • At the behest of astronomer Carl Sagan, the cameras were turned towards Earth one final time to capture the image.
    • After this, the cameras and other instruments on the craft were turned off to ensure its longevity.

    About Voyager 1

    • Voyager 1 is a space probe launched by NASA on September 5, 1977.
    • Having operated for more than 42 years, the spacecraft still communicates with the Deep Space Network to receive routine commands and to transmit data to Earth.
    • At a distance of 148.67 AU (22.2 billion km) from Earth as of January 19, 2020 it is the most distant man-made object from Earth.
    • The probe’s objectives included flybys of Jupiter, Saturn, and Saturn’s largest moon, Titan.

    The Family Portrait of the Solar System

    • The Pale blue dot image was a part of series of 60 images designed to produce what the mission called the ‘Family Portrait of the Solar System’.
    • This sequence of camera-pointing commands returned images of six of the solar system’s planets, as well as the Sun.

  • SuperCam on Mars Rover 2020

     

    In its mission to Mars this summer, NASA is sending a new laser-toting robot called SuperCam as one of seven instruments aboard the Mars 2020 rover.

    SuperCam

    • Called SuperCam, the robot is used for studying mineralogy and chemistry from up to about 7 metres away.
    • It might help scientists find signs of fossilized microbial life on Mars.
    • SuperCam packs what would typically require several sizable pieces of equipment into something no bigger than a cereal box.
    • It fires a pulsed laser beam out of the rover’s mast to vaporise small portions of rock from a distance, providing information that will be essential to the mission’s success.

    NASA lists five things to know

    • From more than 7 m away, SuperCam can fire a laser to study rock targets smaller than a pencil point. That lets the rover study spots it can’t reach with its arm.
    • SuperCam looks at rock textures and chemicals to find those that formed or changed in water on Mars long ago.
    • SuperCam looks at different rock and “soil” types to find ones that could preserve signs of past microbial life on Mars — if any ever existed.
    • For the benefit of future explorers, SuperCam identifies which elements in the Martian dust may be harmful to humans.
    • Scientists can learn about how atmospheric molecules, water ice, and dust absorb or reflect solar radiation. This helps predict Martian weather better.

  • Solar Orbiter (SolO) Probe

     

    Yesterday, the Solar Orbiter, a collaborative mission between the European Space Agency and NASA to study the Sun, took off from Cape Canaveral in Florida.

    What is the Solar Orbiter?

    • Carrying four in situ instruments and six remote-sensing imagers, the Solar Orbiter (called SolO) will face the sun at approximately 42 million kilometres from its surface.
    • Before SolO, all solar imaging instruments have been within the ecliptic plane, in which all planets orbit and which is aligned with the sun’s equator.
    • The new spacecraft will use the gravity of Venus and Earth to swing itself out of the ecliptic plane, passing inside the orbit of Mercury, and will be able to get a bird’s eye view of the sun’s poles for the first time.

    Objectives of the mission

    • The Orbiter will take pictures using telescopes through a heat shield that is partly made of baked animal bones, to help it withstand temperatures of up to 600 degree Celsius.
    • By understanding the behaviour of the sun, the Orbiter aims to provide information on how the former would affect technology such as satellites, navigation systems, power grids, and telecommunication services.
    • The Orbiter will help scientists understand the sun’s dynamic behaviour, and solve mysteries such as the sunspot cycle, or why the star spews out high velocity charged particles through the solar system.
    • With more data on the global magnetic field of the star, scientists would be able to forecast space weather events.

    Earlier missions

    • In 1990, NASA and ESA had sent the Ulysses mission, which also passed over the sun’s poles but at much farther distances, and did not carry a camera.

  • Spitzer Space Telescope

     

    NASA’s Spitzer Mission, which studied the universe in infrared light for more than 16 years, will come to an end since it is low on fuel and has been drifting away from Earth for a few years now.

    Spitzer Space Telescope

    • The Spitzer Space Telescope is a space-borne observatory, one of the elements of NASA’s Great Observatories that include the Hubble Space Telescope and the Chandra X-Ray.
    • Using different infrared wavelengths, Spitzer was able to see and reveal features of the universe including objects that were too cold to emit visible light.
    • Apart from enabling researchers to see distant cold objects, Spitzer could also see through large amounts of gas using infrared wavelengths to find objects that may otherwise have been invisible to human beings.
    • These included exoplanets, brown dwarfs and cold matter found in the space between stars.
    • Spitzer was originally built to last for a minimum of 2.5 years, but it lasted in the “cold” phase for over 5.5 years. On May 15, 2009 the coolant was finally depleted and the “warm mission” began.

    Major discoveries

    • Spitzer also studied some of the most distant galaxies ever detected.
    • The light from these galaxies reached us after traveling for billions of years, enabling scientists “to see those objects as they were long, long ago”.
    • Hubble and Spitzer in 2016 identified and studied the most distant galaxy ever observed.
    • Using these two telescopes, scientists were able to see a bright infant galaxy as it was over 13.4 billion years ago, roughly 400 million years after the Big Bang, when the universe was less than 5% of its current age.
    • It assisted in the discovery of planets beyond our solar system, including the detection of seven Earth-size exo-planets orbiting the star TRAPPIST-1.
    • Three of its seven planets were located in the “habitable zone,” where the temperature might be right for liquid water to exist on the planets’ surfaces.

    Other landmarks

    • Spitzer has logged over 106,000 hours of observation time.
    • Thousands of scientists around the world have utilized Spitzer data in their studies, and Spitzer data is cited in more than 8,000 published papers.
    • Spitzer’s primary mission ended up lasting 5.5 years, during which time the spacecraft operated in a “cold phase,” with a supply of liquid helium cooling three onboard instruments to just above absolute zero.
    • The cooling system reduced excess heat from the instruments themselves that could contaminate their observations.
    • This gave Spitzer very high sensitivity for “cold” objects.
    • In July 2009, after Spitzer’s helium supply ran out, the spacecraft entered a so-called “warm phase.”
    • Spitzer’s main instrument, called the Infrared Array Camera (IRAC), has four cameras, two of which continue to operate in the warm phase with the same sensitivity they maintained during the cold phase.