Indian Space Program: News & Discussion - Sept 2016

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby SSridhar » 26 Oct 2018 09:21

Review: The Leapfroggers - Jeff Foust, The Space Review
The Leapfroggers: An Insider's Account of ISRO
by Ved Prakash Sandlas
HarperCollins India, 2018
paperback, 248 pp.
ISBN 93-5277-941-X
US$19.99

In the United States, it’s commonplace for those involved in spaceflight to write memoirs about their careers: astronauts especially, but also others involved in the development and operation of launch vehicles and spacecraft. Those accounts can provide insiders’ perspectives on various programs, leavened with personal stories and anecdotes that offer a personal touch.

Such memoirs are less common in other nations’ space program, at least in English-language media, but that’s starting to change in India. The Leapfroggers by Ved Prakash Sandlas tells the story of his career in the Indian space agency ISRO, with a particular focus on the development of the country’s first orbital launch vehicle, the SLV-3. It follows on last year’s ISRO: A Personal History by R. Aravamudan, another ISRO official’s account of his work in the early days of India’s space program (see “Review: ISRO: A Personal History”, The Space Review, May 15, 2017).
Told that everything was going well and without any confusion, Abdul Kalam responded, “Come on then, let us create some confusion,” and the two then went and quizzed workers on various aspects of their work.

In The Leapfroggers, Sandlas joins the Indian space program in the late 1960s, working on sounding rockets at the Thumba Equatorial Rocket Launching Station. This leads to work on the SLV-3 rocket, which in July 1980 became the first Indian rocket to place a satellite in orbit (India’s first satellite had been launched on a Soviet rocket a few years earlier.) Sandlas would later go on to run the SLV-3 program through its final few launches as the country transitioned to larger vehicles, including the Polar Satellite Launch Vehicle (PSLV) that is the country’s primary launch vehicle today and the more powerful Geosynchronous Satellite Launch Vehicle (GSLV).

Like Aravamudan’s book, The Leapfroggers is not a thorough, academic history of India’s space program but rather a memoir filled with anecdotes—including many humorous ones—about his work and life. Some of the more interesting ones involve his work with A.P.J. Abdul Kalam, who initially managed the SLV-3 program and would have a long career with Indian space and missile efforts before becoming president of India late in life. “Accurate scheduling was never a priority for Abdul Kalam,” he recalls, noting complaints by some involved with the project for work, such as “unscheduled day-night forced activities.”

On another occasion, Sandlas recalled Abdul Kalam showing up one night and asking how preparations for an upcoming SLV-3 launch were going. Told that everything was going well and without any confusion, he responded, “Come on then, let us create some confusion,” and the two then went and quizzed workers on various aspects of their work. Sandlas endorsed this management approach where “problems should be deliberately triggered to become visible and propagate, so as to find optimal solutions.”

The title of the book comes from comments made by the founder of India’s space program, Vakram Sarabhai, who said country needed “the courage to leapfrog to state-of-the-art engineering and technology pursuits rather than [make] step-by-step scientific developments.” One can argue that India’s space program has followed more of a step-by-step approach: SLV-3 served as the basis for future launch vehicles with gradually increasing performance, whose development (particularly regarding variants of the GSLV) has taken longer than expected. India may not have leapfrogged its way to being one of the leading nations in spaceflight, but some of the early efforts chronicled in The Leapfroggers were essential to the country’s later achievements in space.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 26 Oct 2018 16:52

https://twitter.com/isro/status/1055778204412047360

Scaled down version of Vikram tested

Scaled-down version of #Chandrayaan2 Lander #Vikram completed critical Lander Actuator Performance Test. to demonstrate capabilities of nav, guidance & control system of Vikram for a safe, soft & precise landing on the Moon.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 28 Oct 2018 12:34

Gagan there is no retrorocket firing for water landing.It is only for hard landing
You can see the details of Apollo crew module and have a look at

https://en.wikipedia.org/wiki/Splashdown

The water acts as a cushion negating the need for terminal retro-thrusters..
In Soyuz and Chinese systems since they are landing on the steppe at the last moment retrorockets fire and decrease the speed for hitting the hard earth.
The innate difference is that you can still do a water landing at max of 11m/second (Apollo typically did it less than 9.7 m/second) whereas the speed for landing on a hard surface is much lower for the person to be able to withstand the shock (typically even a parachutist gets a shock equivalent to jumping off from 6-9 feet from the ground with approx 150 lb load and equal to 5m/second ). The Soyuz fires the landing rockets 2.6 feet above the ground to reduce the descent to 1.5 m/second.

it is all about the ability of the body top be bale to tolerate the descent impact forces.

The Americans and Indians choose water landing as a major part of the ascent and abort would have been over water and landing was also chosen over water whereas both Russia and China have to traverse a significant launch abort area over dry land and chose to recover also over land. Soyuz has ability for a water landing too.

orion was planned to have air cushions and terminal retro thrusters for dry landing but it has been given up in favor of water landing.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 28 Oct 2018 12:36

AdityaM wrote:https://www.isro.gov.in/flight-test-of-crew-escape-system-technology-demonstrator-lift-of-video

In this video of the Flight test of crew escape system, the crew pod is released from a height and free falls and splashes hard in the water. The same could happen somewhere over land as well.
So why let the crew pod land like a stone, rather than controlled descent till the very end. the free fall would injure a human occupant
I recall seeing a russian system video which which lands softly after parachutes are released


This is a drop test otherwise the parachute cuts off at landing. The g forces have to be studied to see impact if there is an issue wrt the parachutes.
They did preliminary drop tests with a heliciopter but this was a cut off drop test at a higher speed of descent.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vips » 31 Oct 2018 02:36

Isro-Nasa project finds black hole that spins near max possible rate.

The Indian Space Research Organisation’s (Isro) AstroSat, India’s first dedicated astronomy satellite, in coordination with The National Aeronautics and Space Administration’s (Nasa) Chandra X-ray Observatory has found that a black hole in the binary stellar system 4U 1630−47 spins at a rate that is close to the maximum possible rate.

Researchers said studying black holes with high spin rates is important as it paves the way to test the fundamental laws and theories of the universe, one of which is Albert Einstein’s theory of gravity – general relativity. The significance? Black holes generate the strongest gravitational force in the universe.

A black hole, which is an exotic but a very simple astronomical object, is created when a massive star dies and the matter gets squeezed into a tiny space under a heavy force of gravity, trapping in the light.

Using the X-ray data from AstroSat and Chandra, an international team of astronomers from multiple institutions led by the Tata Institute of Fundamental Research (TIFR) found that the spin rate of the black hole was about 0.9. The spin rate is a dimensionless unit ranging between 0 and 1.

The study comprising an international team of astronomers from multiple institutions and led by TIFR has been accepted for publication in The Astrophysical Journal, a peer-reviewed scientific journal of astrophysics and astronomy.

The findings are significant, said researchers, because so far, high spin rates of only about five black holes have been quantified accurately. Measurement by AstroSat-Chandra is one of them. This is one of the 20 black holes that have been discovered in our galaxy. Each of them about 10 times the mass of the Sun.

“As black holes get created, mass and spin rate are two properties that characterise them. Mass can be measured more easily as it has a long-range effect because of gravity as the black hole gets created,” said Sudip Bhattacharyya of TIFR, and principal investigator of Astrosat’s Soft X-ray Telescope (SXT).

“However, measurements especially of the spin rate are very difficult to make, and can be done only by high-quality X-ray observations in the correct state of the binary stellar system, in which the black hole is a gobbling matter from its companion star”, said the lead author Mayukh Pahari. Pahari started this work at TIFR, before joining a Royal Society-SERB Newton International Postdoctoral Fellow position at the University of Southampton in UK.

It was the indigenously built SXT and Large Area X-ray Proportional Counter (LAXPC) instruments on-board the Astrosat that first observed the black hole in a favourable state so as to be able to interpret the X-ray at the end of 2016. Following this, the Astrosat team requested director of Chandra X-ray Observatory to observe the same black hole. Having independently measured the spin rates of the black hole, the results from Astrosat were consistent with data from Chandra satellite, making the findings robust. Bhattacharyya said, “This is the first cooperation between India and the US using AstroSat and Chandra for black hole studies. Since it was very successful, other collaborations will also now be possible.”


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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Muns » 04 Nov 2018 12:42

Hello guys, we created a 101 video, on upcoming missions for ISRO to try and generate some interest and also popularize Modis vision for 2022 with launching the Indian Gaganaut into space.
To this extent we talked with Sachin of space organization in India which is really involved with teaching school kids about ISRO and upcoming missions. Asked him really a bunch of questions with regard to trying to promote various missions either launched or upcoming by ISRO

Topics are addressed as follows ;

1) Modis vision for launching Gaganaut into space by 2022. The fact that we have such a forward thinking Prime Minister.

2) The success of Mangalyaan, I tried to bring out some information regarding the methane sensor.( To be honest there is not much information online regarding results )

3) Astrosat and what its objectives really are.

4) Aditya and its mission to analyze the chronosphere of the sun.

5) Cartosat and its valuable half meter resolution when it comes to defense or public planning.

6) SV200 boosters and a basic outline of Avatar RLV.

7) New Indian companies and organizations that are apart from ISRO and maybe game changes in the times ahead.

All in all each of these topics as above are really touched upon and briefly explained. I'm not sure if any new gyan when it comes to real ISRO buffs, more of a real 101 for newbies.
Also please realize that it is a 40 minute video to try and explain all of the concepts above. However for space buffs I feel, they will still find it interesting.



www.india-aware.com

www.youtube.com/c/indiaaware

Sub and share...

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 11 Nov 2018 17:34

Seems that integration at the second launch pad is going on and the countdown for GSLV Mk !! launch is going ahead according to some Telugu paper(I could not read it but the news was in a reddit discussion)

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby SSridhar » 11 Nov 2018 18:18

The new cyclone in BoB is likely to cross the coast between Cuddalore & SHAR on 14th !

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vips » 11 Nov 2018 22:25

Isro to launch communication satellite specifically for J&K and NE on Nov 14.

Indian Space Research Organisation (Isro) is gearing up for the launch of a communication satellite on November 14 that is specifically meant for Jammu and Kashmir and northeastern regions.

Talking to TOI, Isro chairman K Sivan said, “Isro will launch Gsat-29 from Sriharikota on November 14. It is an advanced highthroughput communication satellite which will have two Ku and Ka operational payloads. The payloads are meant to provide communication services to J&K and northeastern regions under the ‘Digital India’ programme. The high-speed bandwidth will help bridge the digital divide in hinterland.” Sivan said Gsat-29 will be “lifted off by GSLV-MkIII rocket, which will be the second development flight of Isro’s heaviest rocket”.

Gsat29 will also serve as a platform for testing new space technologies. In addition to operational payloads, the Isro chief said the “satellite will also carry three demonstration technologies — Q and V bands, optical communication and a high-resolution camera. These new technologies will be tested for the first time for their use in future space missions”.

The chairman said India’s heaviest satellite Gsat-11 weighing over 5.7 tonnes, which was earlier recalled from French Guiana to check for any possible anomalies, “will now be launched from the European spaceport on December 4”. Gsat-11 is also a highthroughput communication satellite that will help usher in high-speed internet era in the country.

On the country’s highly ambitious Chandrayaan-II mission, Sivan said, “We are targeting to launch the Chandrayaan mission on January 3. If some slippage happens, we have the launch window till February 16. We can launch the mission any day before February 16.”

On lunar payloads, the chairman said, “The orbiter, lander and rover were being tested for the lunar mission. In fact, three-stage tests were conducted on the lander since last month. Some corrective measures were taken after the initial test. During the final phase of the lander actuator performance test, all on board systems like computer, software and propulsion systems were together tested at the Isro centre in Mahendragiri, Tamil Nadu and all the tests were successful.”

The assembling of the GSLV Mk III rocket, which will carry the lunar spacecraft, that usually takes 50 days, “will be done well in time before January 3”, the chairman said.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Rakesh » 11 Nov 2018 22:28

Rakesh Sharma: ISRO could emerge as the go-to agency for low-cost access to space
https://www.livemint.com/Leisure/ywH9C6 ... r-low.html

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby arun » 11 Nov 2018 22:44



Other forthcoming launches besides GSLV Mk III / GSAT 29 on November 14th are as follows per information attributed to VSSC Director S Somnath.

PSLV-C43 / HySIS plus 30 Nano Satellites on November 26th.

GSLV Mk II / GSAT 7A on December 14th.

Isro lines up 3 rocket launches in two months

Then off course GSLV Mk III / Chandrayaan II between Jan 3 and Feb 16 of 2019:

Vips wrote:Isro to launch communication satellite specifically for J&K and NE on Nov 14.

.........Rest Snipped.........

On the country’s highly ambitious Chandrayaan-II mission, Sivan said, “We are targeting to launch the Chandrayaan mission on January 3. If some slippage happens, we have the launch window till February 16. We can launch the mission any day before February 16.”

On lunar payloads, the chairman said, “The orbiter, lander and rover were being tested for the lunar mission. In fact, three-stage tests were conducted on the lander since last month. Some corrective measures were taken after the initial test. During the final phase of the lander actuator performance test, all on board systems like computer, software and propulsion systems were together tested at the Isro centre in Mahendragiri, Tamil Nadu and all the tests were successful.”

The assembling of the GSLV Mk III rocket, which will carry the lunar spacecraft, that usually takes 50 days, “will be done well in time before January 3”, the chairman said.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Varoon Shekhar » 11 Nov 2018 23:15

https://www.isro.gov.in/launcher/gslv-m ... 29-mission

ISRO has put up some information about the launch. A lift off on Wednesday will be subject to weather conditions. Cyclone brewing in Bay of Bengal.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby JayS » 12 Nov 2018 01:31

What parameters govern this launch window for Chandrayaan-2 which is till 16 Feb..? What stops the window at 16 Feb..?

Earth-Moon relative positioning should not be a big issue I would tend to think. Can't be weather too.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Kakarat » 12 Nov 2018 03:17

There is a possibility of the GSLV MKIII D2 getting postpone due to cyclone in Bay of Bengal, which according to current expected track will be in its flight path

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby SSridhar » 12 Nov 2018 08:49

JayS wrote:What parameters govern this launch window for Chandrayaan-2 which is till 16 Feb..? What stops the window at 16 Feb..?

Earth-Moon relative positioning should not be a big issue I would tend to think. Can't be weather too.

JayS, the distance between Earth & Moon (lunar perigee & apogee) constantly changes. Obviously, ISRO would like to reach the moon when it is nearest to earth. Chandrayan-I took 21 days to reach the moon in a series of orbit raising manoueveres. Chandrayan-II should also have a similar approach, may be more optimized now learning from the experience. On 9th Jan, moon is 406,117 km away and on 22nd Jan 2019 it would be only 357,342 km, a significant reduction of 50,000 Kms.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 12 Nov 2018 09:03

The window is determined by the need to have the best lighting conditions as the entire duration is one lunar day ie one fortnight. We are using solar panels and not an RTG so the rover can work only for 15 days.The launch has to occur to optimise insertion during the start of a lunar day. The latitude of landing site will significantly influence this.
Other things will include visibility from ground stations,flight fuel optimization to a lesser extent ( as we will be dping mulriole orbital raising maneuvers ) and other parameters.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby A Nandy » 12 Nov 2018 10:37

Isro looking at pool of 10 experiments in space

https://timesofindia.indiatimes.com/ind ... 582995.cms

The proposed orbit for the experiments is an earth-bound orbit at an altitude of about 400km around earth. “The enclosure for conducting the experiments will have normal room temperature (tentatively 0-4 degree Celsius) and pressure conditions (tentatively around one atmospheric pressure at sea level) experienced on earth,” Isro said.

However, payloads that need to be placed outside the enclosure will be subject to normal space environment — thermal, vacuum and radiation — conditions and instruments are required to be designed to survive vibration and acoustics loads during launch and return.

Since Isro is planning two kinds of payloads/instruments — internal and external — the agency also has the option of conducting experiments remotely. They can be commanded from the ground, if required.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby JayS » 12 Nov 2018 12:53

SSridhar wrote:
JayS wrote:What parameters govern this launch window for Chandrayaan-2 which is till 16 Feb..? What stops the window at 16 Feb..?

Earth-Moon relative positioning should not be a big issue I would tend to think. Can't be weather too.

JayS, the distance between Earth & Moon (lunar perigee & apogee) constantly changes. Obviously, ISRO would like to reach the moon when it is nearest to earth. Chandrayan-I took 21 days to reach the moon in a series of orbit raising manoueveres. Chandrayan-II should also have a similar approach, may be more optimized now learning from the experience. On 9th Jan, moon is 406,117 km away and on 22nd Jan 2019 it would be only 357,342 km, a significant reduction of 50,000 Kms.


But this is the change in distance due to eccentricity of Moon orbit, you have pointed out. Which means its a 1-month cycle. If ISRO says they can launch any day before 16 Feb if they miss intended date of 3 Jan, it means the mission is already programmed for any changes in the Moon position in the orbit. This cannot be the reason to stop the window at 16 Feb. Any restrictions due to Moon's position in its orbit should roughly have a monthly cycle too i.e. Moon's orbital period around Earth. As such in my opinion distance of 50k KM or position of Moon around Earth should not be a big restriction.

On the country’s highly ambitious Chandrayaan-II mission, Sivan said, “We are targeting to launch the Chandrayaan mission on January 3. If some slippage happens, we have the launch window till February 16. We can launch the mission any day before February 16.”


prasannasimha wrote:The window is determined by the need to have the best lighting conditions as the entire duration is one lunar day ie one fortnight. We are using solar panels and not an RTG so the rover can work only for 15 days.The launch has to occur to optimise insertion during the start of a lunar day. The latitude of landing site will significantly influence this.
Other things will include visibility from ground stations,flight fuel optimization to a lesser extent ( as we will be dping mulriole orbital raising maneuvers ) and other parameters.


Again, if ISRO says they can launch any day between 3 Jan to 16 Feb, this should be irrelevant as they seems to have mission planned to take into account the variations. You can always land of the day side of the moon on a fixed location when the day starts there, in a certain interval in every lunar day i.e. Earth Month. Then the window should be a few specific days each month, isn't it..? And not a continuous one from 3 Jan to 16 Feb. Interestingly the window is not even a full Lunar orbit period, its about 1.5 orbit periods. Which is what made me wonder.

All the factors you mentioned - visibility from ground station, fuel optimization etc should also have monthly cycle i.e. during specific days of each lunar month they should find optimum. Also ISRO has quite a bit of spare fuel anyhow, as we have seen from Mangalyaan mission, with all sort of contingencies accounted for already, giving good cushion.

So what exactly stops the window on 16th Feb. Does the Moon orbit changes (precession..?) in ways which would make things sub-optimal...?

PS: Quick googling tells me all the three precessions should have very small impact on the orbit during a period of say 2-3 months.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby A Nandy » 12 Nov 2018 21:01

Last edited by A Nandy on 12 Nov 2018 21:12, edited 1 time in total.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Rakesh » 12 Nov 2018 21:04

Beautiful picture. Gorgeous!

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby rsingh » 12 Nov 2018 22:04

Why on earth would somebody choose pink colour for such important installation?

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Prasad » 12 Nov 2018 22:33

Eh. I like it. Beautiful pictures.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Indranil » 13 Nov 2018 00:25

rsingh wrote:Why on earth would somebody choose pink colour for such important installation?

What's wrong with pink? I find the paint scheme very tasteful!

I grew up in "quarters" which were always painted (white-washed) pink. It was only when I moved to the west, and Bollywood started making insenstive one-tracked potrayal of gay people, that I realized that pink is not "manly".

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Amber G. » 13 Nov 2018 01:00

rsingh wrote:Why on earth would somebody choose pink colour for such important installation?

Many space agencies think Pink is cool..also
"Today the bright pink paint is helping NASA’s aeronautical innovators test new aircraft designs that could cut fuel use in half, pollution by some 75 percent and noise to nearly one-eighth of what it is today.-

Image

From (Nasa site):
Power of Pink Provides NASA with Pressure Pictures

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Rakesh » 13 Nov 2018 03:38

Indranil wrote:I grew up in "quarters" which were always painted (white-washed) pink. It was only when I moved to the west, and Bollywood started making insenstive one-tracked potrayal of gay people, that I realized that pink is not "manly".

At the bolded part :)

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 13 Nov 2018 06:41

I think the colr of the paint has no bearing on ISRO's functionality. Its a matter of artistic or architectural and individual perception. I did not even think of it nor was I botgered about it.on seeing the VAB. Lets stop discussing it

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vips » 13 Nov 2018 07:46

Kakarat wrote:There is a possibility of the GSLV MKIII D2 getting postpone due to cyclone in Bay of Bengal, which according to current expected track will be in its flight path


Cyclone 'Gaja' shifting track to align with Tamil Nadu coast.

Cyclone 'Gaja', which lies over West-Central and adjoining East-Central and South-East Bay of Bengal, has started shifting track, orienting itself towards the Tamil Nadu coast hundreds of kilometres away.

India Met Department (IMD) has located the cyclone to 730 km east­-north-east of Chennai and 820 km east­north-east of Nagapattinam, respectively to the North and South along the Tamil Nadu coast.

IMD has maintained its outlook for further movement of the system to the west-south-west and its intensification likely towards this evening and stay as such until tomorrow evening. Thereafter, while continuing to move west-south-west, it may weaken a round to being a conventional cyclone and cross the coast between Nagapattinam and Chennai by Thursday morning.

The US Joint Typhoon Warning Centre has suggested that the landfall could happen more towards the South of both Chennai and Puducherry, and hints Nagapattinam and neighbourhood as the target area.

But it doubted the prospects of the cyclone weakening on hitting the home stretch, and suggested that it could pack peak winds of 111 km/hr gusting to 138 km/hr at the time of landfall.

The US National Weather Centre sees the remnant of 'Gaja' crossing the South Peninsula and entering the Arabian Sea off Kerala-Karnataka and regaining traction for sometime.

A weather tracker employed by it is of the view that 'Gaja' could likely set a trend for the Bay waters to get surfed up by a follow-up weather system or two over the next 10 to 15 days.

According to IMD, North Coastal Tamil Nadu (including Chennai) and adjoining South Coastal Andhra Pradesh may start receiving rains generated by severe cyclone 'Gaja' from Wednesday evening.

Most places along the stretch would receive rain with heavy rain likely at isolated places, before the intensity of rainfall picks up on Thursday even as a weakened cyclone approaches the coast. During this phase, most places along North Tamil Nadu may receive rain with very to heavy heavy rain at a few places, while it will be extremely heavy (20 cm and above) at isolated places.

Rainfall at most places with very to very heavy falls is also indicated for South Coastal Tamil Nadu, South Coastal Andhra Pradesh and Rayalaseema on Thursday, the day of landfall. Squally winds with speed reaching 55 km/hr and gusting to 65 km/hr are likely to commence along and off North Tamil Nadu and Puducherry coasts and South Andhra Pradesh from Wednesday evening.

These could gradually become gale wind speeds reaching 90 km/hr gusting to 100 km/hr along and off North Tamil Nadu and Puducherry coasts from Wednesday night.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 13 Nov 2018 09:46

JayS have a look at this wrt lunar launch windows
https://history.nasa.gov/afj/launchwindow/lw1.html

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby JayS » 13 Nov 2018 14:07

prasannasimha wrote:JayS have a look at this wrt lunar launch windows
https://history.nasa.gov/afj/launchwindow/lw1.html


Thanks. A lot of interesting info. I only skimmed through it as of now. Will need to read it slowly to digest all of it. But a whole lot of factors dictating the terms here is due to the Manned mission requirements, some of which were rather stringent. Chandrayaan does not have to consider them and a few other factors can be accounted for due to better technology.

As far as the launch window is concerned, as I expected its few hours each day for few specific days in each lunar month. The space vehicle can always be parked in Earth orbit to wait until right moment for Trans Lunar orbit or by adjusting orbit raising maneuvers accordingly. (For the Apollo mission described in the link they had a restriction on parking orbits due to available battery life of only 13 hours, shouldn't be an issue for ISRO). This explains why ISRO can launch anyday between 3 Jan to 16Feb. They can park Chandrayaan in the earth orbit or adjust the orbit raising accordingly. But I am still looking for answer why not after Feb 16..?

Could that be due to some other planned launch from the same launch pad..?

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Prithwiraj » 13 Nov 2018 14:47

Our fasination with red flags being important. Amazing pics

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby arun » 13 Nov 2018 19:44

Image


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Re: Indian Space Program: News & Discussion - Sept 2016

Postby SaiK » 13 Nov 2018 20:02

rsingh wrote:Why on earth would somebody choose pink colour for such important installation?

I thought you would prepend on the "beautiful picture" showing no proper rain/storm water drainage system. :P .

let's have another naarmal nirmal launch.

--
ps: the pic wouldn't have been beautiful w/ that mirror image.
Last edited by SaiK on 13 Nov 2018 20:04, edited 1 time in total.

SSridhar
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Re: Indian Space Program: News & Discussion - Sept 2016

Postby SSridhar » 13 Nov 2018 20:03

There is one significant difference between NASA to moon and ISRO to moon. They have a Direct Transfer to Moon's orbit while we go in multiple orbit raising at perigee.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Varoon Shekhar » 13 Nov 2018 21:35

^^^
Is that ever a beautiful picture of the GSLV Mark 3. Is the SVAB now fully commissioned( colour scheme issue aside :-)) because there has been no official statement. The vehicle has more propellant loading in the core first stage and the cryogenic stage. The strap-on lengths have been increased from 25.3 m to 26.2 m. Probably HTVE are used in the liquid core stage.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby JayS » 13 Nov 2018 22:25

SSridhar wrote:There is one significant difference between NASA to moon and ISRO to moon. They have a Direct Transfer to Moon's orbit while we go in multiple orbit raising at perigee.

Hence I added mention to orbit raising in my post. The link provided by prasanna didnt have that one. But looks like NASA did have plan for parking orbit in case launch does not happen at optimal time for direct short to Moon.


Chandrayaan 1 Orbits. Shows parking orbit around Earth which is raised gradually till injection to trans Lunar orbit. Theoretically, once launched, Chandrayaan can wait in Earth parking orbit or Moon parking orbit or both til it has optimal moment for landing at designated point on the moon. If the plan is single shot to moon then launch window becomes rather critical.

Image

PS: I found this very nice video on how to calculate launch window for Saturn mission. Old Nasa video. Same info as the link by Prasanna, not as comprehensive though, but with nice graphical explanations. As per this, for one specific landing point there would be one day per month available. A few hours on that specific day. Thats considering direct launch to the Moon without waiting in parking orbits, I suppose.


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Re: Indian Space Program: News & Discussion - Sept 2016

Postby Indranil » 13 Nov 2018 22:56

Jay,

I don't know the real reason. A little short on time to find out. So, I am waiting for you to spoon feed. But, IIRC the savings is not a lot (in the order of about 50-100 kgs of fuel).

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby disha » 14 Nov 2018 00:39

JayS wrote:Could that be due to some other planned launch from the same launch pad..?


Tracking and communication. Particularly tracking and communication required by partner space agencies and tracking & comm stations. Each launch sequence needs a commitment on time and resource allocation from partner agencies/tracking stations. This is pure logistics.

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Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 14 Nov 2018 09:55

GSLVMk3D2 launch is planned for today . Webcast and DD will start and lsunch is at 5.08 IST


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