Studying Earth’s extended magnetosphere (geotail)plasma around Moon
Oct 03, 2019
Our Sun emits a continuous out-flowing 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.
The figure shows the change in intensity of particle events (believed to be mostly electrons), sometimes as much as 10 times the levels outside the geotail, indicating complex interplay with the magnetic field.
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.
Studying Earth’s extended magnetosphere (geotail)plasma around Moon - ISRO
This experiment is a continuation of the same geotail study experiments initially conducted by the Chandrayan-1 using the Chandrayaan-1 X-ray Spectrometer(C1XS). The instrument used by the CY-2 is an evolution of the original C1XS called the Chandrayaan-2 Large Area Soft X-ray Spectrometer(CLASS).
You can read about those CY-1 experiments here :
http://prints.iiap.res.in/bitstream... while in lunar orbit by the Chandryaan 1.pdf
More on the CLASS :
Mapping lunar surface chemistry: new prospects with the Chandrayaan-2 Large Area Soft x-ray Spectrometer (CLASS) - INSPIRE-HEP
Here are some photos of the CLASS :
Solar flare observed by the Solar X-ray Monitor on Chandrayaan-2
Oct 10, 2019
Many violent phenomena continuously keep occurring on surface of the Sun and its atmosphere known as the corona. This solar activity follows an eleven-year cycle, which means, it goes through its 'solar maxima' and 'solar minima' once every eleven years. While the cumulative emission of solar X-rays emitted over a year varies with the solar cycle, these are often punctuated with extremely large x-ray intensity variations over very short periods, few minutes to hours. Such episodes are known as solar flares.
Chandrayaan-2 orbiter utilizes X-rays emitted by the Sun in a clever way to study elements on the lunar surface. Solar X-rays excite atoms of constituent elements on the lunar surface. These atoms when de-excited emit their characteristic X-rays (a fingerprint of each atom). By detecting these characteristic X-rays, it becomes possible to identify various major elements of the lunar surface. However, in order to determine their concentration, it is essential to have simultaneous knowledge of the incident solar X-ray spectrum.
The Chandrayaan-2 orbiter carries two instruments, Chandrayaan 2 Large Area Soft X-ray Spectrometer (CLASS) and Solar X-ray Monitor (XSM), to measure the lunar elemental composition using this technique. Here, the CLASS payload detects the characteristic lines from the lunar surface and the XSM payload simultaneously measures the solar X-ray spectrum.
Currently, the solar cycle is heading towards minima and the Sun has been extremely quiet for past few months. On 30th September 2019 00:00 UTC - 1st October 2019 23:59 UTC, a series of small flares were observed by XSM.
The figure shows the solar X-ray flux as measured by XSM (in blue) during this period, and for comparison, the flux measured by X-ray sensor on the Geostationary Operational Environmental Satellite (GOES-15) is also shown (in orange), which is considered the standard for solar X-ray intensity measurement.It shows that XSM is able to detect the intensity variations of the Sun much beyond the sensitivity limit of GOES. The gaps seen in GOES light curve around 09:00 UTC are due to instrumental artifacts. The GOES data was obtained from the National Center for Environmental Information of National Oceanic and Atmospheric Administration, USA.
Apart from the better sensitivity, XSM also measures the spectrum of solar X-ray in the energy range of 1 - 15 keV with highest energy resolution so far for any broadband solar X-ray spectrometer over intervals as short as 1 second.
Although this solar flare observed at present may not enable the study of the lunar surface composition due to the large angle between Sun, lunar surface and Chandrayaan-2 (close to 90 deg in this case against a desirable low value, close to zero), such XSM observations provide very useful data to understand various processes on the Sun.
Solar flare observed by the Solar X-ray Monitor on Chandrayaan-2 - ISRO
Oct 10, 2019
Many violent phenomena continuously keep occurring on surface of the Sun and its atmosphere known as the corona. This solar activity follows an eleven-year cycle, which means, it goes through its 'solar maxima' and 'solar minima' once every eleven years. While the cumulative emission of solar X-rays emitted over a year varies with the solar cycle, these are often punctuated with extremely large x-ray intensity variations over very short periods, few minutes to hours. Such episodes are known as solar flares.
Chandrayaan-2 orbiter utilizes X-rays emitted by the Sun in a clever way to study elements on the lunar surface. Solar X-rays excite atoms of constituent elements on the lunar surface. These atoms when de-excited emit their characteristic X-rays (a fingerprint of each atom). By detecting these characteristic X-rays, it becomes possible to identify various major elements of the lunar surface. However, in order to determine their concentration, it is essential to have simultaneous knowledge of the incident solar X-ray spectrum.
The Chandrayaan-2 orbiter carries two instruments, Chandrayaan 2 Large Area Soft X-ray Spectrometer (CLASS) and Solar X-ray Monitor (XSM), to measure the lunar elemental composition using this technique. Here, the CLASS payload detects the characteristic lines from the lunar surface and the XSM payload simultaneously measures the solar X-ray spectrum.
Currently, the solar cycle is heading towards minima and the Sun has been extremely quiet for past few months. On 30th September 2019 00:00 UTC - 1st October 2019 23:59 UTC, a series of small flares were observed by XSM.
The figure shows the solar X-ray flux as measured by XSM (in blue) during this period, and for comparison, the flux measured by X-ray sensor on the Geostationary Operational Environmental Satellite (GOES-15) is also shown (in orange), which is considered the standard for solar X-ray intensity measurement.It shows that XSM is able to detect the intensity variations of the Sun much beyond the sensitivity limit of GOES. The gaps seen in GOES light curve around 09:00 UTC are due to instrumental artifacts. The GOES data was obtained from the National Center for Environmental Information of National Oceanic and Atmospheric Administration, USA.
Apart from the better sensitivity, XSM also measures the spectrum of solar X-ray in the energy range of 1 - 15 keV with highest energy resolution so far for any broadband solar X-ray spectrometer over intervals as short as 1 second.
Although this solar flare observed at present may not enable the study of the lunar surface composition due to the large angle between Sun, lunar surface and Chandrayaan-2 (close to 90 deg in this case against a desirable low value, close to zero), such XSM observations provide very useful data to understand various processes on the Sun.
Solar flare observed by the Solar X-ray Monitor on Chandrayaan-2 - ISRO
Initial imaging and observations by Chandrayaan-2 Dual-Frequency Synthetic Aperture Radar (DF-SAR)
Oct 22, 2019
Moon has been continuously bombarded by meteorites, asteroids and comets since its formation. This has resulted in the formation of innumerable impact craters that form the most distinct geographic features on its surface. Impact craters are approximately circular depressions on the surface of the moon, ranging from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins.In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. The study of the nature, size, distribution and composition of impact craters and associated ejecta features reveal valuable information about the origin and evolution of craters. Weathering processes result in many of the crater physical features and ejecta material get covered by layers of regolith, making some of them undetectable using optical cameras. Synthetic Aperture Radar (SAR) is a powerful remote sensing instrument for studying planetary surfaces and subsurface due to the ability of the radar signal to penetrate the surface. It is also sensitive to the roughness, structure and composition of the surface material and the buried terrain.
Previous lunar-orbiting SAR systems such as the S-band hybrid-polarimetric SAR on ISRO’s Chandrayaan-1 and the S & X-band hybrid-polarimetric SAR on NASA’s LRO, provided valuable data on the scattering characterisation of ejecta materials of lunar impact craters. However, L & S band SAR on Chandraayan-2 is designed to produce greater details about the morphology and ejecta materials of impact craters due to its ability of imaging with higher resolution (2 - 75m slant range) and full-polarimetric modes in standalone as well as joint modes in S and L-band with wide range of incidence angle coverage (9.5° - 35°). In addition, the greater depth of penetration of L-band (3-5 meters) enables probing the buried terrain at greater depths. The L & S band SAR payload helps in unambiguously identifying and quantitatively estimating the lunar polar water-ice in permanently shadowed regions.
A convenient approach towards discerning the radar information is to prepare images using two derived parameters, ‘m’ the degree of polarization and ‘ä’ the relative phase between the transmit-receive polarized signals.
Figure 1 shows the m-ä decomposition images of the first datasets acquired over lunar south polar regions in L-band high-resolution (2m slant-range resolution) hybrid polarimetric mode. It produces colour composite images where ‘even-bounce’, ‘volume or diffused’ and ‘odd-bounce’ scatterings of a pixel are represented in red (R), green (G), and blue (B) image planes, respectively. It is important to note that the obtained resolution is one-order better than the earlier best by a lunar-radar.
Figure 1: Conceptual diagram explaining different types of Radar scattering mechanismson lunar surface and sub-surface
Figure-2 presents many interesting facts about the secondary craters of different ages and origins in the lunar south polar region. The yellowish tone around crater rims in the image shows ejecta fields. The distribution of ejecta fields, whether uniformly distributed in all directions or oriented towards a particular side of a crater, indicates the nature of the impact. The image shows craters of vertical impact and oblique impact on the top-right and bottom-right, respectively. Similarly, the roughness of the ejecta materials associated with the impact craters indicates the degree of weathering a crater has undergone. Three similar sized craters along a row on the bottom-right of the image shows examples of young crater, moderately weathered crater and an old degraded crater. Many of the ejecta fields seen in the image are not visible in high-resolution optical image over the same region, indicating the ejecta fields are buried beneath regolith layers.
Figure 2
Chandrayaan-2 Orbiter’s DF-SAR has been operated in full-polarimetry mode- a gold standard in SAR polarimetry, and is the first-ever by any planetary SAR instrument. Figure 3 shows an L-band fully-polarimetric, 20m slant-range resolution image of Pitiscus-T crater. The image is a colour composite of different transmit-receive polarization responses of the imaged region.
Figure-3
Initial imaging and observations by Chandrayaan-2 Dual-Frequency Synthetic Aperture Radar (DF-SAR) - ISRO
Oct 22, 2019
Moon has been continuously bombarded by meteorites, asteroids and comets since its formation. This has resulted in the formation of innumerable impact craters that form the most distinct geographic features on its surface. Impact craters are approximately circular depressions on the surface of the moon, ranging from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins.In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. The study of the nature, size, distribution and composition of impact craters and associated ejecta features reveal valuable information about the origin and evolution of craters. Weathering processes result in many of the crater physical features and ejecta material get covered by layers of regolith, making some of them undetectable using optical cameras. Synthetic Aperture Radar (SAR) is a powerful remote sensing instrument for studying planetary surfaces and subsurface due to the ability of the radar signal to penetrate the surface. It is also sensitive to the roughness, structure and composition of the surface material and the buried terrain.
Previous lunar-orbiting SAR systems such as the S-band hybrid-polarimetric SAR on ISRO’s Chandrayaan-1 and the S & X-band hybrid-polarimetric SAR on NASA’s LRO, provided valuable data on the scattering characterisation of ejecta materials of lunar impact craters. However, L & S band SAR on Chandraayan-2 is designed to produce greater details about the morphology and ejecta materials of impact craters due to its ability of imaging with higher resolution (2 - 75m slant range) and full-polarimetric modes in standalone as well as joint modes in S and L-band with wide range of incidence angle coverage (9.5° - 35°). In addition, the greater depth of penetration of L-band (3-5 meters) enables probing the buried terrain at greater depths. The L & S band SAR payload helps in unambiguously identifying and quantitatively estimating the lunar polar water-ice in permanently shadowed regions.
A convenient approach towards discerning the radar information is to prepare images using two derived parameters, ‘m’ the degree of polarization and ‘ä’ the relative phase between the transmit-receive polarized signals.
Figure 1 shows the m-ä decomposition images of the first datasets acquired over lunar south polar regions in L-band high-resolution (2m slant-range resolution) hybrid polarimetric mode. It produces colour composite images where ‘even-bounce’, ‘volume or diffused’ and ‘odd-bounce’ scatterings of a pixel are represented in red (R), green (G), and blue (B) image planes, respectively. It is important to note that the obtained resolution is one-order better than the earlier best by a lunar-radar.
Figure 1: Conceptual diagram explaining different types of Radar scattering mechanismson lunar surface and sub-surface
Figure-2 presents many interesting facts about the secondary craters of different ages and origins in the lunar south polar region. The yellowish tone around crater rims in the image shows ejecta fields. The distribution of ejecta fields, whether uniformly distributed in all directions or oriented towards a particular side of a crater, indicates the nature of the impact. The image shows craters of vertical impact and oblique impact on the top-right and bottom-right, respectively. Similarly, the roughness of the ejecta materials associated with the impact craters indicates the degree of weathering a crater has undergone. Three similar sized craters along a row on the bottom-right of the image shows examples of young crater, moderately weathered crater and an old degraded crater. Many of the ejecta fields seen in the image are not visible in high-resolution optical image over the same region, indicating the ejecta fields are buried beneath regolith layers.
Figure 2
Chandrayaan-2 Orbiter’s DF-SAR has been operated in full-polarimetry mode- a gold standard in SAR polarimetry, and is the first-ever by any planetary SAR instrument. Figure 3 shows an L-band fully-polarimetric, 20m slant-range resolution image of Pitiscus-T crater. The image is a colour composite of different transmit-receive polarization responses of the imaged region.
Figure-3
Initial imaging and observations by Chandrayaan-2 Dual-Frequency Synthetic Aperture Radar (DF-SAR) - ISRO
Vikram crash-landed on the moon’s due to a software glitch: ISRO’s internal report – Indian Defence Research Wing
Vikram crash-landed on the moon’s due to a software glitch
ISRO’s internal report Published November 17, 2019 | By admin SOURCE: THE WEEK A last-minute software glitch led to the failure of the Chandrayaan 2 mission. Vikram Lander crash-landed on the moon’s surface after its guidance software went kaput, according to an internal report presented to the Space Commission. The Indian Space Research Organisaiton (ISRO) designed Chandrayaan 2 to soft-land a probe on the moon, but the Vikram Lander lost control 500m short of the lunar surface and crashed. Efforts are on to locate the lander that was supposed to analyse the moon’s terrain and send back data for 14 days. The glitch was unexpected since the software was functioning well throughout the trial period.
The Vikram Lander successfully glided from a height of 30 kilometres to 5 kilometres. After this “rough braking,” the lander experienced trouble during the “fine braking,” the final stage in which the lander operated only one of its thrusters and slowed down to just 146m per second. The lander veered off its trajectory and crashed 750m away from the intended landing spot. The impact of the crash damaged the machinery on board and the lander went incommunicado.
ISRO’s internal committee, led by Liquid Propulsion System Centre director V. Narayanan, examined the moon’s surface. The committee was also supplied information from space agencies such as NASA. The ISRO has put in place a mission to rectify the mistakes and relaunch Chandrayaan 2 next November. The agency will build a new lander and rover, which will be linked to the Orbiter that is rotating around the moon.
Vikram crash-landed on the moon’s due to a software glitch
ISRO’s internal report Published November 17, 2019 | By admin SOURCE: THE WEEK A last-minute software glitch led to the failure of the Chandrayaan 2 mission. Vikram Lander crash-landed on the moon’s surface after its guidance software went kaput, according to an internal report presented to the Space Commission. The Indian Space Research Organisaiton (ISRO) designed Chandrayaan 2 to soft-land a probe on the moon, but the Vikram Lander lost control 500m short of the lunar surface and crashed. Efforts are on to locate the lander that was supposed to analyse the moon’s terrain and send back data for 14 days. The glitch was unexpected since the software was functioning well throughout the trial period.
The Vikram Lander successfully glided from a height of 30 kilometres to 5 kilometres. After this “rough braking,” the lander experienced trouble during the “fine braking,” the final stage in which the lander operated only one of its thrusters and slowed down to just 146m per second. The lander veered off its trajectory and crashed 750m away from the intended landing spot. The impact of the crash damaged the machinery on board and the lander went incommunicado.
ISRO’s internal committee, led by Liquid Propulsion System Centre director V. Narayanan, examined the moon’s surface. The committee was also supplied information from space agencies such as NASA. The ISRO has put in place a mission to rectify the mistakes and relaunch Chandrayaan 2 next November. The agency will build a new lander and rover, which will be linked to the Orbiter that is rotating around the moon.
“The method I used was very crude. Just have the images open side by side and go through pixel after pixel,” he added.
Shan did have few false positives. “Some of the differences I spotted turned out to be boulders. Then I learnt that reflections from natural objects on the lunar surface will be brighter. I used that information to discard other false positives,” he said.
On October 3, he tweeted tagging NASA and ISRO about a spot, which he believed could have part of the debris. On October 18, he emailed NASA. “But I couldn’t email ISRO since I did not have the right contact.” In the early hours of Tuesday, NASA confirmed his finding and emailed him.
Shan said his colleagues did not take him seriously when he told them that he was trying to find the Lander. “Now, I can go to office and tease them back,” he said jokingly.
He added that Chandrayaan 2 orbiter’s image are of far higher resolution than that of LRO. “If ISRO also makes images public like that of NASA, it will help more aficionados like me to be involved in, and possibly contribute to the research in some small way,” he said.
It was not rocket science, says Chennai techie who spotted Vikram Lander’s debris
Shan did have few false positives. “Some of the differences I spotted turned out to be boulders. Then I learnt that reflections from natural objects on the lunar surface will be brighter. I used that information to discard other false positives,” he said.
On October 3, he tweeted tagging NASA and ISRO about a spot, which he believed could have part of the debris. On October 18, he emailed NASA. “But I couldn’t email ISRO since I did not have the right contact.” In the early hours of Tuesday, NASA confirmed his finding and emailed him.
Shan said his colleagues did not take him seriously when he told them that he was trying to find the Lander. “Now, I can go to office and tease them back,” he said jokingly.
He added that Chandrayaan 2 orbiter’s image are of far higher resolution than that of LRO. “If ISRO also makes images public like that of NASA, it will help more aficionados like me to be involved in, and possibly contribute to the research in some small way,” he said.
It was not rocket science, says Chennai techie who spotted Vikram Lander’s debris
India's CHANDRAYAAN-2 is creating the highest resolution map we have of the moon
MARCH 11, 2020
By Jatan Mehta
India’s space organization, ISRO, launched Chandrayaan-2 to the Moon last year in July. While its lander Vikram crashed on the lunar surface on September 7, the Chandrayaan-2 orbiter continues to orbit the Moon.
The Chandrayaan-2 orbiter hosts an extensive set of instruments to map the Moon and now we get a peek at the data it has sent.
ISRO scientists had submitted a raft of initial results from the orbiter’s mapping instruments to present at the flagship 51st Lunar and Planetary Science Conference in March. This is an annual conference hosted in the United States where more than 2000 planetary scientists and students from across the world attend and present their latest work. However, due to concerns about the Novel Coronavirus, the conference has been cancelled.
Seeing A Crater In The Dark
Chandrayaan-2 orbiter has an optical camera called the Orbiter High-Resolution Camera (OHRC) which captures detailed images of the Moon. OHRC can image at a best resolution of 0.25 meters/pixel, beating NASA Lunar Reconnaissance Orbiter’s (LRO) best of 0.5 meters/pixel.
Back in October, we already saw OHRC flex its muscles by sending images where boulders less than 1 meter in size were clearly visible. And now OHRC has demonstrated imaging an area not directly illuminated by sunlight! It captured an image of a crater floor in shadow by seeing the dim light falling on it that has been reflected from the crater rim!
Left: Image of the lunar surface by the Chandrayaan-2 orbiter. Region R1 is part of a crater not receiving sunlight at the time of image capture. Right: Crater floor in the dark imaged by Chandrayaan-2’s OHRC by seeing the dim reflected light from the crater’s rim. Credit: ISRO
Moving ahead, this capability will be used to image insides of craters on the lunar poles, where sunlight never reaches. Mapping the terrain of polar craters is important because future lunar habitats are believed to be stationed near them, transporting water and other resources from inside them.
Highest Resolution 3D Maps
The Terrain Mapping Camera (TMC 2) onboard Chandrayaan-2 is a stereo imager, meaning it can capture 3D images. It does that by imaging the same site from three different angles, akin to NASA’s LRO, from a 3D image is constructed.
TMC 2 has beamed back images taken from 100 km above the lunar surface and the 3D views generated from them look great. Here is one of a crater and a wrinkled ridge, the latter being a tectonic feature.
Such images are very useful for understanding how lunar features form and get their shape. For example, a 3D image can help construct an accurate picture of the geometry of the impact that formed a crater.
3D view of a crater on the Moon generated from images captured by Chandrayaan-2 orbiter’s Terrain Mapping Camera
3D view of a wrinkled ridge on the Moon generated from images captured by Chandrayaan-2 orbiter’s Terrain Mapping Camera
Over time, Chandrayaan-2 will provide the highest resolution 3D images of the entire Moon, the best case resolution being 5 meters/pixel.
Enhanced Eyes In The Infrared
The Imaging Infrared Spectrometer (IIRS) on Chandrayaan-2 is the successor to the famous Moon Mineralogical Mapper (M3) instrument onboard Chandrayaan-1.
The M3 instrument, which was contributed by NASA, has been publicly acknowledged for its excellent mineral mapping capabilities and detection of water on the Moon. Noah Petro, Project Scientist for LRO, recently noted on Twitter:
“10 years ago today Chandrayaan-1 ended. I was so lucky to be a small part of that mission. The M3 instrument allowed us to take a huge step forward in learning about the composition of our 8th continent!” – Noah Petro, Project Scientist for LRO, on Twitter.
Both IIRS and M3 detect reflected sunlight from the Moon’s surface. Scientists identify minerals on the surface based on the patterns of these reflections. The IIRS boasts nearly twice the sensitivity of M3 in infrared light and the initial results demonstrate to that effect. Here are images of the Glauber crater as seen by IIRS and M3 respectively.
The Glauber crater on the Moon imaged in infrared by Chandrayaan-2’s IIRS and Chandrayaan-1’s M3 respectively
Thanks to M3, scientists now know that the lunar soil does hold trace amounts of water and hydroxyl molecules even in non-polar regions. IIRS onboard Chandrayaan-2 will map water concentrations in the lunar soil with improved sensitivity. Chandrayaan-2’s long-term observations aim to discern how the water content in the lunar soil changes in response to the lunar environment i.e. what the lunar water cycle looks like.
Note that all this is still less amount of water than the driest deserts on Earth. However, the lunar poles host appreciably more water. And that is where Chandrayaan-2’s radar comes into the picture.
Quantifying Water On The Moon
The Dual Frequency Synthetic Aperture Radar (DFSAR) onboard the Chandrayaan-2 orbiter is the successor to the Miniature Synthetic Aperture Radar (Mini-SAR) on Chandrayaan-1. DFSAR penetrates the Moon’s surface twice as deeper than Mini-SAR. Not just that, DFSAR also boasts a higher resolution than the radar onboard LRO called Mini-RF. The initial results demonstrate as much, comparing a DFSAR radar image of region with Mini-RF.
A region on the Moon imaged by ISRO Chandrayaan-2’s radar (leftmost), NASA LRO’s radar (centre) and LRO’s visible light camera.
With greater penetration depth and higher resolution than any prior instruments, Chandrayaan-2’s orbiter is in the process of adequately quantifying just how much water ice is trapped beneath the permanently dark crater floors on the Moon’s poles. Current estimates based on past observations suggest that the Moon’s poles host more than 600 billion kg of water ice, equivalent to at least 240,000 Olympic-sized swimming pools.
What’s Next ?
The lunar science and exploration communities agree that we can harness water ice on the Moon’s poles to power future lunar habitats. Using solar power generated by the habitats, we can also split the water ice into hydrogen and oxygen for use as rocket fuel.
But before we plan habitats at the Moon’s poles, we need to know more about the nature of water ice in these regions and how to access it given their terrain. The initial results from Chandrayaan-2 clearly show the promise of the highest resolution mapper ever sent to the Moon. ISRO has stated that Chandrayaan-2 will orbit the Moon for seven years and that should be ample time to fully map and quantify water and their host regions on the Moon.
Surface missions that explore these water-hosting permanently shadowed regions, like NASA’s upcoming VIPER rover, are the next logical step towards sustainable habitats on the Moon. As we develop technologies that tap into water ice on the Moon, we can colonize not just our celestial neighbour but the Solar System. We should be glad our Moon has plenty of water; we can’t keep dragging everything out of Earth’s gravitational well forever.
India's Chandrayaan 2 is Creating the Highest Resolution Map We Have of the Moon - Universe Today
MARCH 11, 2020
By Jatan Mehta
India’s space organization, ISRO, launched Chandrayaan-2 to the Moon last year in July. While its lander Vikram crashed on the lunar surface on September 7, the Chandrayaan-2 orbiter continues to orbit the Moon.
The Chandrayaan-2 orbiter hosts an extensive set of instruments to map the Moon and now we get a peek at the data it has sent.
ISRO scientists had submitted a raft of initial results from the orbiter’s mapping instruments to present at the flagship 51st Lunar and Planetary Science Conference in March. This is an annual conference hosted in the United States where more than 2000 planetary scientists and students from across the world attend and present their latest work. However, due to concerns about the Novel Coronavirus, the conference has been cancelled.
Seeing A Crater In The Dark
Chandrayaan-2 orbiter has an optical camera called the Orbiter High-Resolution Camera (OHRC) which captures detailed images of the Moon. OHRC can image at a best resolution of 0.25 meters/pixel, beating NASA Lunar Reconnaissance Orbiter’s (LRO) best of 0.5 meters/pixel.
Back in October, we already saw OHRC flex its muscles by sending images where boulders less than 1 meter in size were clearly visible. And now OHRC has demonstrated imaging an area not directly illuminated by sunlight! It captured an image of a crater floor in shadow by seeing the dim light falling on it that has been reflected from the crater rim!
Left: Image of the lunar surface by the Chandrayaan-2 orbiter. Region R1 is part of a crater not receiving sunlight at the time of image capture. Right: Crater floor in the dark imaged by Chandrayaan-2’s OHRC by seeing the dim reflected light from the crater’s rim. Credit: ISRO
Moving ahead, this capability will be used to image insides of craters on the lunar poles, where sunlight never reaches. Mapping the terrain of polar craters is important because future lunar habitats are believed to be stationed near them, transporting water and other resources from inside them.
Highest Resolution 3D Maps
The Terrain Mapping Camera (TMC 2) onboard Chandrayaan-2 is a stereo imager, meaning it can capture 3D images. It does that by imaging the same site from three different angles, akin to NASA’s LRO, from a 3D image is constructed.
TMC 2 has beamed back images taken from 100 km above the lunar surface and the 3D views generated from them look great. Here is one of a crater and a wrinkled ridge, the latter being a tectonic feature.
Such images are very useful for understanding how lunar features form and get their shape. For example, a 3D image can help construct an accurate picture of the geometry of the impact that formed a crater.
3D view of a crater on the Moon generated from images captured by Chandrayaan-2 orbiter’s Terrain Mapping Camera
3D view of a wrinkled ridge on the Moon generated from images captured by Chandrayaan-2 orbiter’s Terrain Mapping Camera
Over time, Chandrayaan-2 will provide the highest resolution 3D images of the entire Moon, the best case resolution being 5 meters/pixel.
Enhanced Eyes In The Infrared
The Imaging Infrared Spectrometer (IIRS) on Chandrayaan-2 is the successor to the famous Moon Mineralogical Mapper (M3) instrument onboard Chandrayaan-1.
The M3 instrument, which was contributed by NASA, has been publicly acknowledged for its excellent mineral mapping capabilities and detection of water on the Moon. Noah Petro, Project Scientist for LRO, recently noted on Twitter:
“10 years ago today Chandrayaan-1 ended. I was so lucky to be a small part of that mission. The M3 instrument allowed us to take a huge step forward in learning about the composition of our 8th continent!” – Noah Petro, Project Scientist for LRO, on Twitter.
Both IIRS and M3 detect reflected sunlight from the Moon’s surface. Scientists identify minerals on the surface based on the patterns of these reflections. The IIRS boasts nearly twice the sensitivity of M3 in infrared light and the initial results demonstrate to that effect. Here are images of the Glauber crater as seen by IIRS and M3 respectively.
The Glauber crater on the Moon imaged in infrared by Chandrayaan-2’s IIRS and Chandrayaan-1’s M3 respectively
Thanks to M3, scientists now know that the lunar soil does hold trace amounts of water and hydroxyl molecules even in non-polar regions. IIRS onboard Chandrayaan-2 will map water concentrations in the lunar soil with improved sensitivity. Chandrayaan-2’s long-term observations aim to discern how the water content in the lunar soil changes in response to the lunar environment i.e. what the lunar water cycle looks like.
Note that all this is still less amount of water than the driest deserts on Earth. However, the lunar poles host appreciably more water. And that is where Chandrayaan-2’s radar comes into the picture.
Quantifying Water On The Moon
The Dual Frequency Synthetic Aperture Radar (DFSAR) onboard the Chandrayaan-2 orbiter is the successor to the Miniature Synthetic Aperture Radar (Mini-SAR) on Chandrayaan-1. DFSAR penetrates the Moon’s surface twice as deeper than Mini-SAR. Not just that, DFSAR also boasts a higher resolution than the radar onboard LRO called Mini-RF. The initial results demonstrate as much, comparing a DFSAR radar image of region with Mini-RF.
A region on the Moon imaged by ISRO Chandrayaan-2’s radar (leftmost), NASA LRO’s radar (centre) and LRO’s visible light camera.
With greater penetration depth and higher resolution than any prior instruments, Chandrayaan-2’s orbiter is in the process of adequately quantifying just how much water ice is trapped beneath the permanently dark crater floors on the Moon’s poles. Current estimates based on past observations suggest that the Moon’s poles host more than 600 billion kg of water ice, equivalent to at least 240,000 Olympic-sized swimming pools.
What’s Next ?
The lunar science and exploration communities agree that we can harness water ice on the Moon’s poles to power future lunar habitats. Using solar power generated by the habitats, we can also split the water ice into hydrogen and oxygen for use as rocket fuel.
But before we plan habitats at the Moon’s poles, we need to know more about the nature of water ice in these regions and how to access it given their terrain. The initial results from Chandrayaan-2 clearly show the promise of the highest resolution mapper ever sent to the Moon. ISRO has stated that Chandrayaan-2 will orbit the Moon for seven years and that should be ample time to fully map and quantify water and their host regions on the Moon.
Surface missions that explore these water-hosting permanently shadowed regions, like NASA’s upcoming VIPER rover, are the next logical step towards sustainable habitats on the Moon. As we develop technologies that tap into water ice on the Moon, we can colonize not just our celestial neighbour but the Solar System. We should be glad our Moon has plenty of water; we can’t keep dragging everything out of Earth’s gravitational well forever.
India's Chandrayaan 2 is Creating the Highest Resolution Map We Have of the Moon - Universe Today
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Mystery of Chandrayaan 2: Vikram lander, Pragyan rover spotted? Techie awaits ISRO, NASA nod on debris lost in space
Shanmuga Subramanian, a Chennai-based techie and space enthusiast who was credited by NASA late last year for spotting the debris of India's Chandrayaan-2 moon probe - Vikram lander, has come up with his latest find. This time he claims to have possibly spotted the skeleton of the Vikram lander and also the Pragyan rover that might have rolled out onto the lunar surface. The claim is based on a similar method he had employed for the earlier find - by studying and comparing open source moon images shared by NASA. After having written to both ISRO and NASA, he is enthusiastically hoping for the best.
Notably, the Vikram lander had crash-landed near the south pole of the moon and had since been lost. Efforts are on to find the lost space technology on the surface of the moon.
Shanmuga Subramanian told WION that his earlier find was of the debris (perhaps a part of the payload that the Vikram lander was carrying on-board) from the crash landing, as also acknowledged by NASA. But this time around, he's likely to have located the outer shell of the Vikram lander and also the Pragyan rover which has rolled out onto the lunar surface. He has also tweeted out images of his possible find and mailed them to ISRO and NASA, who would be the best authorities to judge and confirm the possible find.
When asked about what led him to embark on this tedious search again, he says he was spending the recent weeks trying to locate other debris on the moon such as the first-ever probe sent by the erstwhile Soviet Union.
"Using an open-source NASA software I've been looking at various regions in-depth. The area was around where the earlier debris was spotted was also of particular interest" he told WION.
He says that the most interesting aspect was a few images clicked by NASA in January, that were made publicly available in May.
"This image was more illuminated due to the then prevailing lighting conditions in that region and enabled me to spot much more. Generally, that region is poorly lit. My latest find (possibly Vikram lander and Pragyan rover) is around 500-700 meters towards the right of the debris that I located last year" he says.
The image he has tweeted out has markings that point to the objects that are suspected to be the Vikram lander, the Pragyan rover, and also the possible tracks of the rover.
Leaving it up to ISRO to confirm, Subramanian suspects that the wheeled rover might have eventually rolled out from the lander after the crash landing.
"Maybe it was pre-programmed to roll out or maybe the lander received ISRO's command to roll our the rover. The lander and rover may have been communicating back and forth. But, perhaps this could have been a case of one-way communication. While the lander and rover could communicate, it was perhaps not able to relay the signals back to Earth after the harsh landing" he says.
WION also got the receipt of Subramanian's e-mail confirmed from ISRO chairman Dr.K.Sivan. "He has sent us the image and we have shared it with our experts for analysis," Dr. Sivan told WION.
India's second moon-probe Chandrayaan 2 was launched on July 22nd last year and had attempted a moon-landing on September 7th. However, the much-anticipated landing happened to end up in a crash landing, after ISRO lost contact with the Vikram lander, barely at an altitude of 2.1km from the lunar surface.
India is also working on Chandrayaan-3, the country's third moon probe, and it is expected to be launched sometime in 2021.
Shanmuga Subramanian, a Chennai-based techie and space enthusiast who was credited by NASA late last year for spotting the debris of India's Chandrayaan-2 moon probe - Vikram lander, has come up with his latest find. This time he claims to have possibly spotted the skeleton of the Vikram lander and also the Pragyan rover that might have rolled out onto the lunar surface. The claim is based on a similar method he had employed for the earlier find - by studying and comparing open source moon images shared by NASA. After having written to both ISRO and NASA, he is enthusiastically hoping for the best.
Notably, the Vikram lander had crash-landed near the south pole of the moon and had since been lost. Efforts are on to find the lost space technology on the surface of the moon.
Shanmuga Subramanian told WION that his earlier find was of the debris (perhaps a part of the payload that the Vikram lander was carrying on-board) from the crash landing, as also acknowledged by NASA. But this time around, he's likely to have located the outer shell of the Vikram lander and also the Pragyan rover which has rolled out onto the lunar surface. He has also tweeted out images of his possible find and mailed them to ISRO and NASA, who would be the best authorities to judge and confirm the possible find.
When asked about what led him to embark on this tedious search again, he says he was spending the recent weeks trying to locate other debris on the moon such as the first-ever probe sent by the erstwhile Soviet Union.
"Using an open-source NASA software I've been looking at various regions in-depth. The area was around where the earlier debris was spotted was also of particular interest" he told WION.
He says that the most interesting aspect was a few images clicked by NASA in January, that were made publicly available in May.
"This image was more illuminated due to the then prevailing lighting conditions in that region and enabled me to spot much more. Generally, that region is poorly lit. My latest find (possibly Vikram lander and Pragyan rover) is around 500-700 meters towards the right of the debris that I located last year" he says.
The image he has tweeted out has markings that point to the objects that are suspected to be the Vikram lander, the Pragyan rover, and also the possible tracks of the rover.
Leaving it up to ISRO to confirm, Subramanian suspects that the wheeled rover might have eventually rolled out from the lander after the crash landing.
"Maybe it was pre-programmed to roll out or maybe the lander received ISRO's command to roll our the rover. The lander and rover may have been communicating back and forth. But, perhaps this could have been a case of one-way communication. While the lander and rover could communicate, it was perhaps not able to relay the signals back to Earth after the harsh landing" he says.
WION also got the receipt of Subramanian's e-mail confirmed from ISRO chairman Dr.K.Sivan. "He has sent us the image and we have shared it with our experts for analysis," Dr. Sivan told WION.
India's second moon-probe Chandrayaan 2 was launched on July 22nd last year and had attempted a moon-landing on September 7th. However, the much-anticipated landing happened to end up in a crash landing, after ISRO lost contact with the Vikram lander, barely at an altitude of 2.1km from the lunar surface.
India is also working on Chandrayaan-3, the country's third moon probe, and it is expected to be launched sometime in 2021.
Mystery of Chandrayaan 2: Vikram lander, Pragyan rover spotted? Techie awaits ISRO, NASA nod on debris lost in space
As Chandrayaan-2's mystery continues even after a year post its launch, Shanmuga Subramanian, a Chennai-based techie and space enthusiast, has come up with his latest find after scanning debris lost in space. This time around, he's likely to have located the outer shell of the Vikram lander and...
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