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Indian Space Programme Discussion - Sept 2016

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abhik
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Re: Indian Space Programme Discussion - Sept 2016

Postby abhik » 27 Nov 2017 20:31

Indranil wrote:...Image
...

In the image, is the semi cryo engine a "vacuum" version (high expansion ratio) or "Sea Level" version - or will it have to be changed depending on the version?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Vips » 28 Nov 2017 22:18

Here comes the Sun Watcher - India's Aditya - L1.

Sometime in 2019 or 2020 India will send ISRO’s solar mission Aditya-L1 to a vantage point in space, known as the L1 Lagrange point, to do imaging and study of the sun. This launch will happen in the early part of the next solar cycle - an occurrence in which sunspots form on the face of the sun, growing in size and number and eventually diminishing, all over a period of eleven years. It will be a mission of many firsts.

The so-called L1 point is 1.5 million kilometres away. Here, due to the delicate balance of gravitational forces, the satellite will require very little energy to maintain its orbit. Also it will not be eclipsed from the sun. The 1,500-kg class satellite will be programmed to orbit this point and image the sun’s magnetic field from space for the very first time in the world. Scientists hope to capture the close-ups of the sun from here, uninterrupted by eclipses for years.

Few other space agencies have successfully placed their satellites at this location. Among the few, the Solar and Heliospheric Observatory (SOHO), a NASA-ESA collaboration involving America and Europe, and NASA’s Advanced Composition Explorer (ACE) are at L1 exclusively to study the sun and space weather, respectively. Aditya-L1 is expected to be the very first to study from space two months from the time of launch, the magnetic field of the sun’s corona. The corona is the outer layer that we see during total solar eclipses. It will be the first 100% Indian mission which will not only negotiate a challenging orbit, but will also benefit the global scientific community in understanding the sun.

Deeper look
Earlier, the NASA-ESA mission SOHO was launched in 1995, and while it made many discoveries, its coronagraph, meant to image the sun, broke down shortly after the mission commenced. Hence there is currently no satellite imaging the sun from space. Aditya-L1 will not only fill this gap it will also literally, look deeper into the sun than SOHO. “The nominal mission lifetime is expected to be five years, though it is expected to go on for much longer, perhaps even ten,” says Dipankar Banerjee from Indian Institute of Astrophysics (IIAP), Bengaluru, which is collaborating with ISRO on this project.

The mission will carry seven payloads,consisting of a coronagraph, equipment that will image the sun using ultraviolet filters, X-ray spectrometers, and particle samplers all being made within the country.

The largest payload, or instrument, aboard the satellite, will be the Visible Emission Line Coronagraph (VLEC). This can view the sun more closely than has been done before even by SOHO.

With this advantage, the instrument has the capacity to observe the loop-like magnetic structures that form in the corona, the outer layer of the sun. “This will be the first experiment to measure the coronal magnetic field from a space platform. This was not even done by SOHO,” says Dipankar Banerjee, the Science Working Group Chair of VELC.

Between them, the three payloads — VLEC, the Solar Ultraviolet Imaging Telescope (SUIT) and the X-ray spectrometers — can image the sun in all wavelengths.

Like seasonal changes on the earth, the sun experiences approximately eleven-year-long cycles during which sunspots, caused by the sun’s magnetic field, start forming, increase in the ascending phase and decrease in the descending phase towards the end of the cycle.

“Studying coronal mass ejections [a phenomenon that would correlate with high sunspot activity] is not the only objective. This study can also help us understand the coronal heating problem,” says Prof. Banerjee. The ‘coronal heating problem’ refers to the fact that the photosphere, a deeper layer of the sun, is at a much lower temperature than the outer layer, the corona. Since it is believed that the heating process happens from within, what causes this heating of the outer layer, the corona, remains a mystery. Observations by Aditya-L1 of the magnetic fields bubbling out of the photosphere into the corona will help shed light on this.

First proposed in 2008 as a 400 kg-class satellite with one scientific instrument, a coronagraph, the project has since changed and grown in size and scope. Aditya-L1 will carry seven payloads. Each of these will either image the sun or sample the space around it for traces of charged particles spewed out by the sun during coronal mass ejections.

The payloads alone will weigh close to 250 kg. The biggest of these is the VLEC, about 170 kg. The next is SUIT, weighing around 35 kg; others are much lighter. Orbiting about the L1 point, due to a play of gravitational forces acting on it, Aditya-L1 will require little energy to keep it in place.

The ultraviolet (UV) imaging payload will capture the sun using UV filters, something that is not possible from Earth. the wavelength range 200-400 nanometres. This is The range of ultraviolet light to be observed is prevented from entering the lower layers of the earth’s atmosphere by the ozone layer in the stratosphere. Ozone depletion can lead to this radiation filtering through to lower levels where it can have harmful effects. Since this radiation is stopped at the stratosphere, images of the sun in this wavelength cannot be obtained on earth. Therefore, this will be the first time a UV imaging of the sun will be done.

Durgesh Tripathi and A.N. Ramaprakash of Inter University Centre for Astronomy and Astrophysics (IUCAA) are the principal investigators for the SUIT payload. “When it was decided that the project expanded and the satellite was to be placed in L1 point, ISRO called for proposals for developing more instruments. The original payload was also improved to form the VLEC and six more payloads were added,” says Prof. Tripathi.

Apart from this, the two in situ particle-detection payloads - Aditya Solar wind Particle EXperiment (ASPEX) and Plasma Analyser Package for Aditya (PAPA) will study aspects that affect space weather. the origin of solar wind ions, their reaction to coronal mass ejections, the distribution of these in the heliosphere – the space around the sun that extends up to Pluto - and so on. The various payloads in Aditya-L1 will also study space weather.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 29 Nov 2017 01:09

^^^ With Aditya - from Langrage point L1 - not only sun but IMO watching earth will be nice too. Always sunlit face, same place..
Like this from L1: (NASA released to the world the first image of the sunlit side of Earth captured by the space agency's EPIC camera on NOAA's DSCOVR satellite. The camera has now recorded a full year of life on Earth from its orbit at Lagrange point 1
Enjoy:



Rakesh
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Re: Indian Space Programme Discussion - Sept 2016

Postby Rakesh » 30 Nov 2017 06:02

ISRO banks on private players as it plans series of satellite launches
http://www.business-standard.com/articl ... 319_1.html

The Indian agency is looking to rope in private participation to overcome barriers in the way of becoming a global player in the space arena.

Image

prasannasimha
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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 30 Nov 2017 23:47

Someone was asking about the Nozzle of the semicro engine - it is adapted for dense atmosphere penetration so is narrower relying on barometric presure to keep the flame compacter.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Manish_P » 01 Dec 2017 12:37

Youth from Powai slums becomes first ever Mumbaikar to qualify as ISRO scientist

Pratamesh Hirve, 25, is boldly going where no Mumbaikar has gone before. After years of burning the midnight oil in his humble 10X10 ft home at the Filterpada slums in Powai, the youth has become the first ever from the city to qualify for the elite Indian Space Research Organisation (ISRO). Now, he has the entire universe ahead of him.

Pratamesh's journey to the dizzying heights of space research is all the more amazing because of his humble beginnings. Living in a 10x10 house in the heavily populated Filterpada slums, it took every ounce of Pratamesh's willpower to focus on his studies and never lose sight of his goal.


"My aunt and parents had taken me for an aptitude test in south Mumbai. The specialist told my parents that my cousin brother had the aptitude for engineering, but that I should choose a career in Arts instead. I was upset, but refused to give up. I told my parents that no matter what, I would become an engineer, and they believed in me,"


Is that right? No one from Mumbai in ISRO! :cry: As a mumbaikar i feel :oops:

Anyway wish the young man the best for the future. May he make ISRO and the Nation proud.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 01 Dec 2017 13:02

^ Nonsense I know people from Mumbai who have joined ISRO

Manish_P
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Re: Indian Space Programme Discussion - Sept 2016

Postby Manish_P » 01 Dec 2017 14:50

I thought so too... guess it is the usual DDMitis

Anyway good work by the lad. May he do the country proud

In more (DDM) news - ISRO Wants Indian Engineers! :lol:

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Re: Indian Space Programme Discussion - Sept 2016

Postby JTull » 01 Dec 2017 15:58

Anyone who has worked in either knows that ISRO and BARC have common roots. It's silly to think there are no Mumbaikars in ISRO.

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Re: Indian Space Programme Discussion - Sept 2016

Postby symontk » 01 Dec 2017 20:21

JTull wrote:Anyone who has worked in either knows that ISRO and BARC have common roots. It's silly to think there are no Mumbaikars in ISRO.

There are several folks from MH, famous being, https://en.wikipedia.org/wiki/Vasant_Gowarikar

But may be no one from proper Mumbai

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Re: Indian Space Programme Discussion - Sept 2016

Postby Mihaylo » 02 Dec 2017 02:50

symontk wrote:
JTull wrote:Anyone who has worked in either knows that ISRO and BARC have common roots. It's silly to think there are no Mumbaikars in ISRO.

There are several folks from MH, famous being, https://en.wikipedia.org/wiki/Vasant_Gowarikar

But may be no one from proper Mumbai


To drill it down further, maybe none from the slums.

-M

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Re: Indian Space Programme Discussion - Sept 2016

Postby NRao » 05 Dec 2017 07:31

India, Japan Aim For Joint Moon Mission

NEW DELHI—India and Japan are planning a joint mission to the Moon—the second time the two countries have teamed up for a lunar probe.
The Indian Space Research Organization (ISRO) and Japan Aerospace Exploration Agency (JAXA) have started working out the contours of their collaborative mission. It is aimed at capturing samples of Moon rock for deeper observation.

“We are looking at a possible joint lunar mission,” ISRO Chairman A.S. Kiran Kumar said. “The plan is in a very preliminary stage. We are working on the details at the moment.”

JAXA President Naoki Okumura says that an “implementation agreement” will be finalized within the next two months.

The pre-phase studies to decide the mission’s focus should be clear in the next six months, he adds.

The heads of the two space agencies did not provide a time frame for the mission’s launch.

The plan is the result of a November 2016 agreement between the governments of India and Japan. At that time the prime ministers of both countries signed a deep space explorations agreement.

Team Indus—an aerospace startup based in the south Indian city of Bengaluru—is aiming to carry a Japanese rover on the Moon by March 2018. It is the first-ever private company to undertake such a mission.

The mission would be the third for both countries. Japan launched the Hiten Spacecraft in 1990, the country’s first lunar probe. In 2009, JAXA’s lunar orbiter spacecraft Selene impacted the lunar surface after successfully orbiting the Moon for a year and eight months.

India launched its first lunar probe in 2008 through Chandrayaan-1, which only orbited the Moon. The country is now planning an advanced version called Chandrayaan-2. It is a composite model comprising three crucial parts—the orbiter, lander and rover—with a set of sensors and communication equipment to help the three connect with each other.

In recent years, India and Japan have been working to enhance cooperation in space exploration and the use of outer space for future missions.

In January the two sides signed cooperative documents addressing lunar exploration, satellite navigation and X-ray astronomy.

The two countries are also discussing using their space technologies for weather monitoring and climate change studies.

With the latest agreement on the joint lunar mission, India and Japan will lead the space sector in the Asia-Pacific region.

“We hope we can do it as soon as possible,” Okumura said.

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Re: Indian Space Programme Discussion - Sept 2016

Postby srai » 05 Dec 2017 13:17

Manish_P wrote:Youth from Powai slums becomes first ever Mumbaikar to qualify as ISRO scientist

Pratamesh Hirve, 25, is boldly going where no Mumbaikar has gone before. After years of burning the midnight oil in his humble 10X10 ft home at the Filterpada slums in Powai, the youth has become the first ever from the city to qualify for the elite Indian Space Research Organisation (ISRO). Now, he has the entire universe ahead of him.

Pratamesh's journey to the dizzying heights of space research is all the more amazing because of his humble beginnings. Living in a 10x10 house in the heavily populated Filterpada slums, it took every ounce of Pratamesh's willpower to focus on his studies and never lose sight of his goal.


"My aunt and parents had taken me for an aptitude test in south Mumbai. The specialist told my parents that my cousin brother had the aptitude for engineering, but that I should choose a career in Arts instead. I was upset, but refused to give up. I told my parents that no matter what, I would become an engineer, and they believed in me,"


Is that right? No one from Mumbai in ISRO! :cry: As a mumbaikar i feel :oops:

Anyway wish the young man the best for the future. May he make ISRO and the Nation proud.

First from the Mumbaikar slums that is :wink:

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Re: Indian Space Programme Discussion - Sept 2016

Postby SKrishna » 12 Dec 2017 17:29

AW&ST is honouring ISRO and Planet Labs with their annual Laurate award in Operations category. :D :D

Other awardees are SpaceX in Launchers and Boeing in platform category.

Just received a mailer to this effect. So no link.. :-?

Another feather in ISRO's cap.



<edited for spelling>

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Re: Indian Space Programme Discussion - Sept 2016

Postby krishGo » 16 Dec 2017 18:10

abhik wrote:In the image, is the semi cryo engine a "vacuum" version (high expansion ratio) or "Sea Level" version - or will it have to be changed depending on the version?


SCE-200 will be an earth lit engine like most semi cryogenic engines. It will be a core stage engine (or even boosters in the future). It should probably operate in vacuum / near vacuum conditions only during the later last part of its life cycle. There are upper stage engines like the Merlin Vacuum which are specifically designed to be started and operate mainly in vacuum conditions.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 17 Dec 2017 00:42

Is there a lull in ISRO launches or am I missing launches?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Ashokk » 17 Dec 2017 01:34

ISRO to launch remote sensing satellite of Cartosat-2 series in January 2018
India: Indian space agency, ISRO will launch its latest remote sensing satellite of the Cartosat-2 series, along with 28 foreign satellites in the first week of January, according to a top ISRO official. Director of Thiruvananthapuram-based Vikram Sarabhai Space Centre (VSSC), K Sivan clarified that there will be no launch this month and that launch services, which halted after the unsuccessful launch of navigation satellite IRNSS-1H on August 31, will “resume in the first week of the new year”.

In an interview with Rakesh Sasibhushan, CMD, Antrix (the commercial arm of ISRO) told TOI: “The January launch payload will comprise a combination of one Cartosat, 25 nano-satellites, and three micro-satellites. Finland is the new customer this time. The rest co-passengers are from existing foreign customers. Most of these small satellites are from the US.”

The launch of Cartosat-2 by the PSLV C40 rocket is a follow-on mission of the Cartosat-2 series with the primary objective of providing high-resolution scene-specific spot imageries. The satellite, which carries panchromatic and multi-spectral cameras, is capable of delivering high-resolution data.

Sivan said, “After the Cartosat mission, the subsequent launch will be of Gsat-6A that will be lifted off by a GSLV Mk II rocket”. “The launch of navigation satellite IRNSS-1I, which will replace the first navigation satellite IRNSS-1A, whose three atomic clocks (meant to provide precise locational data) had stopped working last year, is planned in February or March,” he said, adding, “Next in line will be the Chandrayaan-2 mission, scheduled for launch in March.”

The series of satellite launches scheduled next year is in line with ISRO chairman A S Kiran Kumar’s recent statement to TOI that the space agency is planning to double the number of launches from eight to 10 to 18-20 annually. Kiran Kumar also said that though the space agency currently has “45 satellites in orbit, the country is significantly short of communication satellites. Therefore we have to maximise launches”.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 17 Dec 2017 21:00

4 launches till end march!
That is quite a speed of launches.

High capacity higher tonnage satellites will be needed if the transponder shortage is ever going to be addressed.
Just like the IAF's 42 squadron requirement, India's satellite transponder requirement is an unfulfilled task, which only goes up as the country rapidly develops and digitizes at this furious pace !
Looking forward to the GSLV Mk3 being fully functional and launching 4-6 tonner geo-sats

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Re: Indian Space Programme Discussion - Sept 2016

Postby Varoon Shekhar » 19 Dec 2017 21:27

http://www.newindianexpress.com/nation/ ... 30985.html

January 10/2018 launch for the next PSLV with about 29 satellites.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Varoon Shekhar » 19 Dec 2017 21:36

Gagan wrote:4 launches till end march!
That is quite a speed of launches.

if the transponder shortage is ever going to be addressed.
t, India's satellite transponder requirement is an unfulfilled task, which only goes up as the country rapidly develops and digitizes at this furious pace !


In the last 3 years, there have been quite a few geosynchronous comm sats launched, GSAT-16, GSAT-15, GSAT-18, GSAT-17, all by Ariane. Then the Indian launches, GSAT-14, GSAT-6, GSAT- 9 and GSAT-19. That's a pretty good list, though India still needs more. What's interesting is that it is hard to find information as to what satellite is broadcasting what TV channels, and how many channels. Or even what precisely these satellites are being used for. If it's for telecom, as opposed to I&B, why not just display that information somewhere.

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Re: Indian Space Programme Discussion - Sept 2016

Postby vasu raya » 30 Dec 2017 23:39

With the aim of 24*7 surveillance on the LoC given its difficult terrain and foliage, the following statement sums the problem,

http://idrw.org/india-has-42-satellites-but-needs-double-that-number-to-meet-its-basic-needs/#more-158320

Low-earth orbiting satellites used for surveillance take more than 90 minutes to go around the earth, underscoring the need for a large number of constellations of such satellites to look at specific spots for a finite period, he (Indian Space Research Organisation chief A.S. Kiran Kumar) added.


So far the Israel supplied RISAT-2 which has X-band SAR seems to be useful for surveillance and they improved on the resolution in their follow on Sats. If India can obtain Phalcon radars, would Israel be willing to give the latest X-band SAR sats? like the https://en.wikipedia.org/wiki/Ofek-11

another approach is having a constellation of micro sats that provide near continuous coverage and in real time of the whole region. ISRO is experimenting with IMS-A, B and they also have the famed 104 sat launch under their belt, only if they can manage to put SAR sensors with good enough resolution

Bridging these two approaches is a challenge and here they have a multi static operation with micro sats only being used as SAR receivers and Sentinel-1 like the Indian built Risat-1 is an emitter in C-band

https://www.researchgate.net/figure/259899025_Fig-1-Illustration-of-PICOSAR-constellation-following-Sentinel-1-satellite-at-a-safe-distance

if we are putting X-band seekers in missiles or fighter radars, can they develop such receive only micro sats for SAR?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 01 Jan 2018 00:11

contrast that with 15 ago when there would be dedicated thread on BRF for each pslv mission, and about 1 mission per year. :)

Any one has the Rocket simulator?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 01 Jan 2018 00:20

vasu raya wrote:.... another approach is having a constellation of micro sats that provide near continuous coverage and in real time of the whole region. ISRO is experimenting with IMS-A, B and they also have the famed 104 sat launch under their belt, only if they can manage to put SAR sensors with good enough resolution

Bridging these two approaches is a challenge and here they have a multi static operation with micro sats only being used as SAR receivers and Sentinel-1 like the Indian built Risat-1 is an emitter in C-band

https://www.researchgate.net/figure/259899025_Fig-1-Illustration-of-PICOSAR-constellation-following-Sentinel-1-satellite-at-a-safe-distance

if we are putting X-band seekers in missiles or fighter radars, can they develop such receive only micro sats for SAR?

Receiver (multi static style) is no issue, a little challange (all solvable ) to have receive phase coherence and to determine on the fly millimeter level posotion accuracy as the nano sat drifts in space. Some amount of antenna gain on nano sat will be useful (but that is slippery slope to weight gain).

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Re: Indian Space Programme Discussion - Sept 2016

Postby vasu raya » 01 Jan 2018 01:10

^^^
Thank you very much Haridas ji, resolution would be most important, however as was done with the flock nano sats, within a constellation they were having improved variants, such flexibility would mean it would be a continuous process of upgrades until there is a balance between resolution and weight. The on demand capability being developed would also mean less priority for weight but should not be going to the other extreme of 300kg radar sat with long lead time development.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 01 Jan 2018 12:49

abhik wrote:Isro's plan: A rocket that can be made in 3 days
As per this ISRO is developing a 100t launcher which will cost "1/10 of original manufacturing cost of PSLV", payload of 500-700kg and will be ready to launch by end of 2018 or early 2019. Was there reports of this earlier or did ISRO just pull a rabbit out of the hat?


Mini-PSLV with above weight and payload config is per known ISRO capability. First cut using typical stage mass ratios:
1. Booster, Solid fuel, 65 tonne (similar to ISRO proposed S60)
2. Second Stage, Solid fuel, 24 Tonne
3. Third Stage, Solid or Liquid, 1500 Kg

Will easily deliver 700Kg payload to 500 km SSO.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 01 Jan 2018 13:07

Sounds most plausible of all the speculations here.

1. Are you guessing, or do you know this?
2. Diameter?
3. Doesn't seem to reuse any of the current stages!!!

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 01 Jan 2018 13:19

^^^ Saar, just calculations.
First feasibility validation; next form fitting based on available information from public or chaiwalla source.

Reuse make sense when the rockets are comparable or just pure luck. If ISRO wants a rockets 1/10th the cost, 3 days to assemble, 1/3rd the weight and a very different payload/orbit performance, its as good as a new bird. Having conquered K2 climbing,going to Mt.Fuji is relatively cake walk, doesnt mean one will not have to put effort and sweat. But 100T tonne for 700 kg means no need to optimize stage for Mass Fraction, exotic manufacturing etc etc,

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 01 Jan 2018 13:37

Good. Valid reasons.

I was wondering how you were giving out such precise numbers like 24 tons etc.

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Re: Indian Space Programme Discussion - Sept 2016

Postby abhik » 01 Jan 2018 16:12

The PSLV 4th stage could possibly be used in single engine configuration for upper stage, though if only 2 solids are used in the lower stages might have to have better propellant mass fraction.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 01 Jan 2018 23:25

abhik wrote:The PSLV 4th stage could possibly be used in single engine configuration for upper stage, though if only 2 solids are used in the lower stages might have to have better propellant mass fraction.

That was my assumption too. Just scaled it to half the size. It's a He pressure fed liquid engine that is elegant for accurate final velocity impartment, apart from being cheap to make, like solid stages.

No saar no improvement assumed, lower 2 solid stages mass fraction same as early pslv confign.
Notice the first cut indicates 90 T configuration, so if one uses 100 ton c0nfig, MF need will be even lower.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 02 Jan 2018 03:20

When you said S60, I thought you were speaking of 60 tons of propellant mass. Were you not?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 02 Jan 2018 05:41

Yes. ISRO engine nomenclature generally reflects approx fuel in the stage in tonnes. All-up wt of stage thus is more, depending on MF.

I think the mini Pslv will be:
1. Booster 60 tonne, 2.8m dia, 9m long (2 segments instead of 5 segments of current pslv S139)
2. Second stage ~24 tonne, 2.8m dia, 5m long (1 segments version of current pslv S139). I think using PSLV 3rd stage based composite case engine will be more expensive and unnecessary high MF.
3. Upper stage ~1.5 tonne, 1.3m dia (single engine version of current pslv upper stage)

Much of experience , process n tooling of current pslv could be leveraged .

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 02 Jan 2018 06:20

IIRC the above configuration will have max aerodynamic stress at ~Mach 1.7 @~2.5 km altitude.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 02 Jan 2018 10:38

Well we don't have anything between the PSOMs and S139, so for a 100 ton rocket a new stage has to be built.

The 2.8 mtr dia is very interesting (if true). It allows reuse of tooling and process, but we are speaking of a very short and fat rocket. The entire rocket is as fat as the PSLV, but only as tall as its first stage!

I hope the second and third stage have a lower diameter.

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Re: Indian Space Programme Discussion - Sept 2016

Postby abhik » 02 Jan 2018 10:43

Haridas wrote:Yes. ISRO engine nomenclature generally reflects approx fuel in the stage in tonnes. All-up wt of stage thus is more, depending on MF.

I think the mini Pslv will be:
1. Booster 60 tonne, 2.8m dia, 9m long (2 segments instead of 5 segments of current pslv S139)
2. Second stage ~24 tonne, 2.8m dia, 5m long (1 segments version of current pslv S139). I think using PSLV 3rd stage based composite case engine will be more expensive and unnecessary high MF.
3. Upper stage ~1.5 tonne, 1.3m dia (single engine version of current pslv upper stage)

Much of experience , process n tooling of current pslv could be leveraged .

What you are saying is that they can get the same performance of pslv-3s by not only removing the 2nd liquid stage (as in the 3s) but also removing over half of the existing first stage AND not using composite casing for the middle solid - what gives? If this works then they can probably remove the 2nd stage liquid stage in the CA version and replace the 3rd stage solid with a larger solid and still get the same performance?

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Re: Indian Space Programme Discussion - Sept 2016

Postby symontk » 02 Jan 2018 10:59

abhik wrote:
Haridas wrote:Yes. ISRO engine nomenclature generally reflects approx fuel in the stage in tonnes. All-up wt of stage thus is more, depending on MF.

I think the mini Pslv will be:
1. Booster 60 tonne, 2.8m dia, 9m long (2 segments instead of 5 segments of current pslv S139)
2. Second stage ~24 tonne, 2.8m dia, 5m long (1 segments version of current pslv S139). I think using PSLV 3rd stage based composite case engine will be more expensive and unnecessary high MF.
3. Upper stage ~1.5 tonne, 1.3m dia (single engine version of current pslv upper stage)

Much of experience , process n tooling of current pslv could be leveraged .

What you are saying is that they can get the same performance of pslv-3s by not only removing the 2nd liquid stage (as in the 3s) but also removing over half of the existing first stage AND not using composite casing for the middle solid - what gives? If this works then they can probably remove the 2nd stage liquid stage in the CA version and replace the 3rd stage solid with a larger solid and still get the same performance?


The proposed Second stage is a new thing and without expensive or extensive testing, it will not fly. I presume ISRO will continue with proven PS3

1 stage - S60
2 stage - PS3 - improved ??
3 stage - PS4 - improved ??

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 02 Jan 2018 12:09

abhik wrote:What you are saying is that they can get the same performance of pslv-3s by not only removing the 2nd liquid stage (as in the 3s) but also removing over half of the existing first stage AND not using composite casing for the middle solid - what gives?

Sir, I just did the first cut calculation for 178 degree N launch without dog leg maneuvering, assuming cheap rocket will be launched from Sso optimized pad.

Yes CA is very unoptimized / overkill for small payload, thus their desire for cheaper config.

abhik wrote:If this works then they can probably remove the 2nd stage liquid stage in the CA version and replace the 3rd stage solid with a larger solid and still get the same performance?

Yes the limited Vikas thrust was imho a contributory reason for the small S8 stage. So yes one can replace the 3rd stage solid motor with heavier solid stage 2.8m dia and maybe just 2 or 3 segments of stage1 will be adequate. Reuse of 2.8m booster facility would be enticing.

I had always wondered why ISRO chose a smaller 2.0m dia for 3rd stage, instead of continuing with 2.8 m dia ! :shock: Maximizing std PSLV performance required fiber case 3rd stage, but that is not needed for smaller payload 100 t config.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 02 Jan 2018 12:19

symontk wrote:The proposed Second stage is a new thing and without expensive or extensive testing, it will not fly. I presume ISRO will continue with proven PS3

1 stage - S60
2 stage - PS3 - improved ??
3 stage - PS4 - improved ??

Its glass half full.... One can alternatively treat it as an improvement, becoz 2nd stage is essentially booster stage comprising tail and head segments only & inside 3 segments missing.

3rd stage could be stripped down version of PS4 (only one engine, smaller fuel tank and smaller helium tanks). Or to keep mass mfg concept, just keep the original PS4.


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