ISRO General News and Updates

[mahesh]

according to ISRO's K. Sivan, Director , IRNSS H1 along with the heatshield and fourth stage would fall back, re-enter and burnout about 40 to 60days.
"The perigee will come down in course of time. Once the perigee touches 100 km then the rate of PSLV's heat shield-satellite assembly's fall towards the earth will be faster."
The exact spot where the satellite housed inside the heat shield will fall will be known around 36 hours before the actual impact.

 

[Vijyes]

according to ISRO's K. Sivan, Director , IRNSS H1 along with the heatshield and fourth stage would fall back, re-enter and burnout about 40 to 60days.
"The perigee will come down in course of time. Once the perigee touches 100 km then the rate of PSLV's heat shield-satellite assembly's fall towards the earth will be faster."
The exact spot where the satellite housed inside the heat shield will fall will be known around 36 hours before the actual impact.

So, it can crash onto someone? Wow! That would be bad. The heat shield may prevent burn out of the satellite and it may become a spiraling meteorite

 

[mahesh]

So, it can crash onto someone? Wow! That would be bad. The heat shield may prevent burn out of the satellite and it may become a spiraling meteorite

Given the orbit in which it is, it is suppose to fall in waters. Even they say the same.

Sent from my irisX8 using Tapatalk

 

[kurup]

^^^^ We should see this as an oppertunity to do a US193 with this sat .

 

[Vijyes]

^^^^ We should see this as an oppertunity to do a US193 with this sat .

Is it possible to shoot down satellites spiralling uncontrollably to the earth just like that? Satellites with stable orbit is a different ballgame.

 

[kurup]

Is it possible to shoot down satellites spiralling uncontrollably to the earth just like that? Satellites with stable orbit is a different ballgame.

Theoretically possible if you are able to predict the trajectory correctly .

US did it in 2008 ....... https://en.wikipedia.org/wiki/USA-193

 

[S.Balaji]

Payload fairing ie heat shield is attached to last stage with Payload adapter which doesn't have thermal protection.
Payload module while on decaying trajectory will undergo a tumble on atmosphere reentry with the breach in Payload adapter initiating burn up.There wont be any debris impact on the ground even from the thermal protected heat shield due to explosion caused by satellite fuel causing heat shield to fragment and burn up.

 

[S.Balaji]

Payload fairing/ heat shield with adapter at the bottom

 

[Cutting Edge 2]

An update on C39 mission.

Analysis is still going on but early data suggests that there might be some issue with explosives or controller. Maybe a glitch in computer code sending commands to controller. Final picture will emerge when full analysis is complete.

 

[Trinetra]

An update on C39 mission.

Analysis is still going on but early data suggests that there might be some issue with explosives or controller. Maybe a glitch in computer code sending commands to controller. Final picture will emerge when full analysis is complete.

Is this an official analysis of ISRO? i would suggest if code problem is der then we should start considering the Chinese involvement in this..

 

[Prayash]

Haze Removal Algorithm developed for Cartosat Images
High resolution optical imaging Earth Observation Satellite (EOS) systems such as CARTOSAT provide multi-spectral remote sensing data in the visible and near-infrared (VNIR) wavelengths of the order of sub-meter to few-meters. These datasets can be used in a variety of applications, particularly associated with precise mapping, monitoring and change detection of earth’s surface, if top of the atmosphere (TOA) measurements can be properly compensated for atmospheric absorption and scattering effects. Existing physics based atmospheric correction (AC) algorithms for multi/hyper-spectral remote sensing data over land involves simultaneous use of visible and short-wave infrared (SWIR) channels to derive aerosol information. Hence, such algorithms cannot be used for AC of data acquired by VNIR sensors to derive “surface reflectance”.

Towards this, Space Applications Centre, Ahmedabad has developed a new algorithm for AC of high resolution VNIR remote sensing data in which aerosol information is retrieved from sensor measurements in VNIR channels and by selecting appropriate aerosol optical properties from a set of defined aerosol models. The algorithm uses lookup tables generated with vector radiative transfer calculations. Derived aerosol information and pre-computed lookup tables are employed to derive surface reflectance. Good quality surface reflectances have been obtained when this algorithm was applied on Cartosat-2 Series Satellite data. It is found that this algorithm significantly removes the haze from the images, making surface features distinctly visible, and hence more useable for qualitative as well as quantitative analysis and further applications.

Following figures illustrate the drastically improved quality of the images after applying the AC algorithms, where contribution of light due to molecular scattering and scattering from thick layer of aerosol to the sensor measurement at top the of the atmosphere is removed:

Parts of Ahmedabad as viewed from Cartosat-2 Series Satellite on 03/11/2016

Cartosat-2 Series Satellite View of Ahmedabad , Satellite Area on 03/11/2016

Cartosat-2 Series Satellite View of Delhi Encompassing IGI Airport on 01/11/2016

Cartosat-2 Series Satellite View of Krasnensky District, Belgorod Oblast, Russia on 01/07/2017

Cartosat-2 Series Satellite View of Jhang District in the Punjab Province of Pakistan on 01/07/2017

 

[charlie]

CE 20 test ..........................................

 

[Prayash]

GUJARAT I-T DEPT USES ISRO SATELLITE IMAGES TO NAIL TAX DEFAULTER
http://ahmedabadmirror.indiatimes.c...il-tax-defaulter/amp_articleshow/60704681.cms

 

[Indx TechStyle]

Story of the Week
Monitoring Larsen C Rift propagation, Calving and Iceberg Deformation: through VEDAS developed Automatic Technique

Antarctica, the southernmost continent, is an ice-covered land mass. 90% of world’s fresh water is in Antarctica. It is broadly divided in to East Antarctica and West Antarctica. Antarctic Peninsula is one of the test beds for monitoring climate variation. The broader categories of ice features of Antarctica include ice sheet (ice layer covering landmass over an extensive period), ice shelf (Floating sheet of ice permanently attached to land mass), iceberg (the floating land ice), glaciers (slowly moving ice mass), ice rise (grounded ice shelf) and sea ice (frozen ocean water).

Larsen C is the fourth largest ice shelf in Antarctica. A rift is a large through fracture that propagates transverse to ice flow direction and acts as a precursor to ice calving. Initially, small cracks form due to longitudinal stress which results into crevasses and finally forms the rift. The rift propagation and calving (the disintegration) of ice into ice berg are natural phenomena in the Antarctic ice margins. Global warming may be attributed as one of the causative factors for the unusual fast rift propagation in the Larsen C in the recent past. This region has thus been the focus of many scientific studies, and regular research related observations. The Larsen C Ice Shelf covers an area of approximately 50,000 square kilometres between Jason Peninsula in the North and Hearst Island in the South. The large scale disintegration of ice shelf into ice bergs and rift propagation has focussed limelight on Larsen C ice shelves during the last decades.

A huge portion of the Larsen C ice shelf (~50,000 square kilometers) in Antarctic Peninsula calved away to an iceberg of area ~6200 square kilometers between 10th July and 12th July, 2017. The iceberg is named as A 68 by scientific community. This event is closely monitored by Team AMHTDG/EPSA/SAC since February 2017, ever since news of the possible detachment of Larsen C from the landmass started appearing on internet and the results of rift was reported by SAC, through SACNET, VYOM and VEDAS. This has created interest among the scientists working in the field of cryosphere science.

An automatic technique was subsequently developed for detecting and monitoring calving events and rift propagation at Larsen C using available SAR data. C band SAR data from Sentinel-1(repeat cycle of 12 days) is made available at a regular interval through https://scihub.copernicus.eu/dhus Copernicus site by European Space Agency. A software module was developed to download and unzip the data automatically from the Copernicus site. A software module developed will check for the data and update the process. The same module is being modified to accommodate the SCATSAT-1 high resolution product (2 km) data which will be soon available in VEDAS and can be used for future RISAT series of data sets.

India, with its two Indian Antarctic research stations Maitri and Bharati, have also been contributing in routine scientific expeditions and scientific research. A similar Monitoring System will be available at VEDAS pertaining to Bharati and Maitri, during the next Indian Scientific Expedition to Antarctica during December 2017 – April 2018. The module for automatic downloading of Sentinel 1 data every 12 days, and monitoring of the region was developed by SAC.

Story of the Week - Archive
Sep 19, 2017 : Monitoring Larsen C Rift propagation, Calving and Iceberg Deformation: through VEDAS developed Automatic Technique
Sep 11, 2017 : NARL Studies tropical tropopause aerosol layer using in-situ observations in collaboration with NASA
Aug 28, 2017 : Haze Removal Algorithm developed for Cartosat Images
Aug 22, 2017 : National Workshop on Popularisation of Remote Sensing Based Maps and Geo-spatial Information
Aug 14, 2017 : ISRO Organises an Outreach Programme in Hindi at Ranchi
Aug 08, 2017 : ISRO Develops Optical Imaging Detector Array for Hyperspectral Imaging Applications
Aug 01, 2017 : Flood Monitoring using SCATSAT-1 Satellite

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[NeXoft007]

Located at Satish Dhawan Space Centre. Is that OTH radar under construction?
Coordinates - 13.717241,80.172609

 

[aliyah]

cant u ppl tell in simple words what it does in end and in very short

 

[Kyubi]

cant u ppl tell in simple words what it does in end and in very short

Over-the-horizon radar, or OTH (sometimes called beyond the horizon, or BTH), is a type of radar system with the ability to detect targets at very long ranges, typically hundreds to thousands of kilometres, beyond the radar horizon, which is the distance limit for ordinary radar.

-wikipedia

Sent from my SM-G935F using Tapatalk

 

[NeXoft007]

cant u ppl tell in simple words what it does in end and in very short

OTH is different than other radars. Its coverage shape is like that of a half donut or arc shape coverage. Which means it can't track anything near its area, but far away. That's because OTH radar radiations hits the ionosphere and reflects back to the area we want to be under surveillance (like a mirror)

 

[Indx TechStyle]

Story of the Week - Indian Space Research Organization
Operationalisation of Thunderstorm Nowcasting Services over NE Region using DWR data

North Eastern Space Applications Centre (NESAC) has been providing thunderstorm nowcasting (forecasting up to 4 hours) services for North Eastern Region (NER) of India since 2015 under the North Eastern Regional node for Disaster Risk Reduction (NER-DRR) initiatives. This was done using the data from satellite imager and sounder onboard INSAT-3D / INSAT-3DR, automatic weather station data, and by analysing numerical weather forecast data. However, it was difficult to detect, track and forecast using this data alone as most of the thunderstorms being localised event, extending only over a few tens of km and having lifetime of less than one hour. The availability of DWR data has opened a new window for precise identification of thunderstorm weather systems, track them and forecast the probable areas which may get affected, albeit with lesser lead time.

The first S-band dual polarimetric Doppler Weather Radar (DWR) was installed at Cherrapunjee, Meghalaya which was dedicated to nation by Shri Narendra Modi, Hon’ble Prime Minister of India on May 27, 2016. NESAC is operating the DWR continuously since then, and the data is made available in near real time for public through the MOSDAC (Meteorological and Oceanographic data archival centre) and IMD websites. The DWR is calibrated at regular intervals and the data and products are being validated. It has unobstructed coverage for the entire state of Meghalaya, Tripura, Southern Assam, and part of Mizoram and Manipur. For the western and central Assam region, the DWR has coverage beyond 3 degree elevation only. The DWR also sees large part of India’s neighboring country, Bangladesh. The radar completes one volume scan in 11 minutes, comprising of 360 degree azimuth scan for 10 elevation angles ranging from 0.5 to 21 degrees. It also allows sector scan (in both azimuth and elevation) for high temporal observation of any event. The DWR covers a distance of 250 km (up to 500 km only for Z) with spatial resolution of 300 m.

Thunderstorm is a pre-monsoon season (April-May) phenomenon over the NER of India. The data collected by the DWR during 2016 was used to understand the thunderstorm and storm signatures and calibrate the nowcasting model. During 2017 the nowcasting service was made operational. Severe thunderstorm nowcasting services for Southern Assam, Meghalaya, and Tripura were done primarily using the DWR data and for the rest of the NER, the earlier methodology was used. In addition to the Z (radar reflectivity), S (spectral width) and V (velocity) data collected by the DWR, extensive use of the polarimetric data like ZDR(differential reflectivity) and ρHV(Correlation coefficient) were also made to differentiate thunderstorm clouds from non-thunderstorm clouds.

Almost all the thunderstorms affecting Meghalaya, southern Assam, and Tripura could be identified using the data from Cherrapunjee DWR during the pre-monsoon season of 2017. The spectral width (S) data was used to characterise the internal turbulence within a cloud system that helped in quantifying the storm potential (S>5) of a particular cloud. Hail potential could also be identified using ZDR(ranging from 0.5 to - 0.5) and ρHV(~0.9) data. The radar reflectivity, Z and its vertical profile (Max Z plots) was the backbone of thunderstorm identification and identification of individual storm cells in large cloud bands that appear in satellite imageries. All clouds having Z value more than 40 dBZ could become a thunder cloud and were tracked in real time. Z of 50-56 dBZ was categorised as severe thunderstorm and Z of more than 56 dBZ was categorised as very severe thunderstorm with hail. The reflectivity and velocity of clouds were studied to track every individual storm and forecast the likely affected areas within certain time intervals, based on sustenance potential of such storms, estimated by analysing the local atmospheric condition.

The use of the Cherrapunjee DWR data has improved the thunderstorm nowcasting accuracy over Meghalaya, Southern Assam, and Tripura states. Altogether 48 severe and very severe thunderstorms were forecasted in these three states during April 1 to June 15, 2017 period. The accuracy of nowcasting was more than 90% with lead time varying from 30 minutes to more than 2 hours. The nowcasting services were disseminated through NER-DRR website and also through direct communication to the concerned at state level.

The DWR, Cherrapunjee coverage for elevation angle of 3 degree (left). Calibration of the DWR using metal sphere attached to hydrogen gas filled balloon & Pisharoty sonde (right)

A squall line formed over Meghalaya, Southern Assam, and Manipur which is clearly identified using DWR data (left). INSAT-3D TIR1 channel image of the same time is also shown (right). The DWR data helped in identifying the individual storm cloud cells in a large cloud band as seen in satellite image

Max V (left) and Max S (right) data from DWR, Cherrapunjee. Max V is used to estimate the velocity at which a weather system is moving and Max S gives an idea about the internal turbulence within cloud system

Story of the Week - Archive
Sep 25, 2017 : Operationalisation of Thunderstorm Nowcasting Services over NE Region using DWR data
Sep 19, 2017 : Monitoring Larsen C Rift propagation, Calving and Iceberg Deformation: through VEDAS developed Automatic Technique
Sep 11, 2017 : NARL Studies tropical tropopause aerosol layer using in-situ observations in collaboration with NASA
Aug 28, 2017 : Haze Removal Algorithm developed for Cartosat Images
Aug 22, 2017 : National Workshop on Popularisation of Remote Sensing Based Maps and Geo-spatial Information
Aug 14, 2017 : ISRO Organises an Outreach Programme in Hindi at Ranchi
Aug 08, 2017 : ISRO Develops Optical Imaging Detector Array for Hyperspectral Imaging Applications

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[Anikastha]

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