ISRO General News and Updates

SKC

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Out of 10 pics taken on first day, 5 are of India and rest of Doha (Qatar) and Alexandriya (Egypt)
 

SanjeevM

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Just a point. Do remember that these pics are for commercial purpose. So just think of those which would be taken for strategic point of view and would be jealously guarded :drool:
The pictures for strategic purposes will be more closer or from same size? I mean it was said satellite images can see number plate of a car. Or identify presence of humans. So if there is a training camp in Pakistan, can we identify it from these pictures?
 

Chinmoy

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The pictures for strategic purposes will be more closer or from same size? I mean it was said satellite images can see number plate of a car. Or identify presence of humans. So if there is a training camp in Pakistan, can we identify it from these pictures?
As I said, this are commercial pics taken by the satellite. These are for general cartographic purposes and could be purchased by any agency for city or block development or any such issue. But for strategic purpose, the resolution would be much more then commercial one. As of now, the advertised resolution of CARTOSAT 2 is less then one meter.
 

mahesh

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The next launch is PSLV-C39 in August first week to place the navigational satellite IRNSS-1H in orbit which is a spare satellite at ground station and will be replacing the IRNSS-1A which has broken all 3 atomic clocks and rendering ineffective to its full capacity, but satellite is in good condition and it is now currently used only for messaging activities. (couldn't find what messaging but found later on - NavIC Messaging: Disaster Warning System not a huge task though)
As many as 45 rubidium atomic clocks were reportedly procured BY ISRO.

additional four more atomic clocks on the other six satellites are not performing as required - ( showing glitches )

ISRO chairman Kumar has indicated the number of satellites could go up from the originally envisaged 7 to 11 but it is not clear if this is a consequence of the failing clocks.
“Measures are being taken to correct the problems caused by the clocks in the launch of future satellites. The atomic clocks to be used in the other satellites have been modified to prevent malfunction,” a senior official in the programme said.

Asked about the failure of the additional clocks, an official ISRO spokesperson said, “We have not been told of any failures other than what has been stated by the ISRO chairman, which is three clocks on IRNSS-1A”

~ additional information ~

FEW NOTABLE THINKS ABOUT THESE ATOMIC CLOCKS

These (Rubidium Atomic Frequency Standard) atomic clocks however, inherent hardware problems on the rubidium atomic clocks in some of these. These clocks developed the same problems when used in the Galileo satellite system by the European Space Agency.
The European Space Agency reported last January that anomalies had occurred in three of 36 Rubidium Atomic Frequency Standard (RAFS) clocks in the 18-satellite Galileo system, although none of the satellites were affected. ESA had said, “These failures all seem to have a consistent signature, linked to probable short circuits, and possibly a particular test procedure performed on the ground.


They have been used in IRNSS despite warnings by senior officials within the system over their efficacy, said a source associated with the satellite navigation programme over the years. ISRO has glossed over this because only experts can find out when information from a satellite is incorrect.

SpectraTime have come to agree that “some refurbishment is required on the remaining RAFS clocks(Rubidium Atomic Frequency Standard Clock)” to be used in new Galileo satellites.
further “We are also in contact with India concerning this interaction and it looks like the behaviour is different on different satellites. It is really very difficult, but we are exchanging information.


Galileo satellite is equipped with four clocks. Two are Rubidium Atomic Frequency Standard (RAFS) clocks like those found in GPS and GLONASS satellites. The other two are the more accurate (and much more complex) Passive Hydrogen Maser (PHM) clocks

A PHM clock uses the properties of the hydrogen atom to serve as a frequency reference. It is a complex and high cost device but has a significantly higher precision than the Rubidium clock. Typically, PHM clocks are expected to have a 20-year lifetime.
20 years of life is too much :p (Even IRNSS have 10 years of life and ESA's GNSS have 12 years but given the random failures of atomic clock IRNSS failed within 3 years with all 3 of them but ESA's handling experience might have saved from failure of all clocks in 1 satellite. )
 

Cutting Edge 2

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Anybody knows the status of indegenious RAFS clock. It was under development as per NPL website.
http://www.nplindia.in/rubidium-atomic-clock-space
Its under development. Currently they are developing 2 variants of clocks. 1) is for ground operations and 2) for space operations. For space operations It will take at least a decade before it becomes mission ready.
Maybe 2025 circa?
 

Prashant12

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Isro develops ship-based tracking antenna terminal

BENGALURU: In order to cater to specific tracking requirements of launch vehicles and post-launch activity, Isro Telemetry, Tracking and Command Network (Istrac), Bengaluru, has designed and developed a 4.6-metre Ship Borne Transportable (SBT) Antenna Terminal that meets the launch vehicle telemetry, tracking and command (TTC) requirements.

Istrac is entrusted with the responsibility of providing tracking support for all satellite and launch vehicle missions of Isro, besides being mandated to provide space operations support for Deep Space Missions.
"For supporting Deep Space Missions, a large number of ground stations are required to provide Telemetry Tracking and Command (TTC) support during the launch and initial phase. Based on the launch vehicle trajectory and visibility requirement, many a time TTC stations are to be located mid-sea, where conventional Ground Station Antenna are not suitable," Isro said in a statement.

It was in this backdrop that Istrac developed a 4.6 metre SBT antenna terminal that meets the launch vehicle TTC requirements.


"The SBT Antenna system consists of 3-axis antenna mount, a motion simulator, reflector and feed, servo control systems and radio frequency electronics. Mechanical Systems Area (MSA) of Istrac made a detailed study of the technical requirements, availability of similar systems internationally and derived state-of-the-art specifications," Isro added.

The final system performance and validation was carried out by a sea trial. The antenna system was integrated on Sagar Manjusha Ship hired by the National Institute of Ocean Technology (NIOT). The ship was stationed at a specified observation point in Bay of Bengal and has successfully tracked the PSLV-C38 launch vehicle.

http://timesofindia.indiatimes.com/...ing-antenna-terminal/articleshow/59555161.cms
 

kunal1123

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ISRO gearing up for second prototype test of RLV-TD

By Tiki Rajwi | Express News Service | Published: 17th July 2017 08:23 AM |
Last Updated: 17th July 2017 08:24 AM | A+A A- |
THIRUVANANTHAPURAM: A little over a year since the successful flight test of the first prototype of the futuristic Reusable Launch Vehicle - Technology Demonstrator (RLV-TD), ISRO is gearing up for a second go. Only this time, the prototype will ‘land’ on land instead of water.
Work is progressing at the Vikram Sarabhai Space Centre (VSSC) here on the second RLV-TD. A senior officer associated with the project said the RLV-TD will almost be a ditto version of the first scaled-down RLV-TD with the only exception being it will have landing gear.
ISRO sources said it may take another year for the model to be ready. They said the present plan is to launch the RLV-TD from Sriharikota and land it on an undisclosed Air Force airfield in the eastern sector. This is yet to be finalised though, they said.

The unmanned RLV-TD comprises a space shuttle-like component fitted atop a booster rocket. The first RLV-TD weighing 1.5 tonnes, was successfully launched from Sriharikota on May 23 last year and splashed down in the Bay of Bengal from a height of 64.8 km.
While VSSC is primarily responsible for building the RLV-TD, the navigational equipment are being provided by the ISRO Inertial Systems Unit in Thiruvananthapuram and ISRO’s Satellite Applications Centre, Ahmedabad. Hindustan Aeronautics Ltd is responsible for the landing gear.
In fact, ISRO plans a series of TDs before attempting to build a fully-fledged vehicle that can be reused for launching satellites. A subsequent TD will possibly involve a slightly larger vehicle which will place a nano-satellite in the orbit.
 

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