GSLV-Mk III launch program/post-launch analysis

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Re: GSLV-Mk III launch program/post-launch analysis

Postby abhik » 07 Jun 2017 22:48

shiv wrote:
abhik wrote:4t to GTO is proven, 6t will be proven very soon. So why this sudden yearning for miniaturization and light sats?

That is easily explained. Someone said ISRO should plan ahead. Fine. But as far as I can tell all the plans seem to be suggestions to copy what others are doing today. 10 ton capability already exists with Ariane and others. So OK we get 6 tons tomorrow and 10 tons later.

What will others do later. 15 tons? 20 tons? 50 tons? There has to be some practical limit to the weight that can be lifted with reasonable effort to 36,000 km. What are we going to do when we reach that limit?

Robotic docking is already in practice. Moving one satellite close to another for docking or colliding with it is also no longer unreachable tech. What would prevent a 16 ton satellite being built in 4 x 4 ton modules to be docked in space to make one big 16 ton satellite. Do we have to wait till we reach 16 ton capability or send it to French Guyana?

That is what I call as thinking ahead. That is all. If you have any well informed thoughts on this I would be happy to hear them.


AFAIK the only things that have been assembled in space because it was too big to launch all at once are the ISS and its Russian predecessors, with the former costing more than $100 billion to build. And docking spacecraft is far from routine, it's mostly used in human spaceflight (ISS resupply missions etc.) and unheard of in the commercial domain. Also ISRO has no experience in docking or assembling in space.
Besides we far from having reached the "practical limit" of what can be launched to space. In another 10 years we might have a launcher that can launch over 500t to space.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby LokeshC » 07 Jun 2017 22:51

In 10 years robotics, miniaturization and AI will make satellites and space stations look unrecognizable from how they look today. I dont usually throw out the "I know better" card, but I say this only because I work in a related area.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby shiv » 07 Jun 2017 23:11

abhik wrote:AFAIK the only things that have been assembled in space because it was too big to launch all at once are the ISS and its Russian predecessors, with the former costing more than $100 billion to build. And docking spacecraft is far from routine, it's mostly used in human spaceflight (ISS resupply missions etc.) and unheard of in the commercial domain. Also ISRO has no experience in docking or assembling in space.


Docking in space for resupply is routine stuff for existing space stations. I think two 4 ton satellites can be docked to make an 8 ton satellite. any reason why this is not possible? If no one else is doing it. We could start. That would give us a lead over others. Why simply run after heavier and heavier launchers just because others are doing it?

Besides we far from having reached the "practical limit" of what can be launched to space. In another 10 years we might have a launcher that can launch over 500t to space.


I don't actually believe this - having heard from the 1960s that we will have colonies in space by the 1990s. Those people who made those claims are now unavailable to be questioned for making wild claims.

GSLV weighed 640 tons at launch and put 3 tons in orbit - a ratio of over 1:200. At best a 500 ton satellite will require a 50,000 ton launcher.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby prasannasimha » 07 Jun 2017 23:18

ISRO is already planning a satellite docking refueling experiment. It serves two purposes. One - satellite rrefueling and second is to finetune docking practice for actual orbital rendezvouz for human flight needs

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Re: GSLV-Mk III launch program/post-launch analysis

Postby prasannasimha » 07 Jun 2017 23:20

Image

Image

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Re: GSLV-Mk III launch program/post-launch analysis

Postby prasannasimha » 07 Jun 2017 23:24

The above is officially called the SPADEX experiment

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Re: GSLV-Mk III launch program/post-launch analysis

Postby disha » 08 Jun 2017 02:29

rsingh wrote:Question to knowledgeable: Do other countries (China, Russia and US) also bring brochures, show live parameters where every nut-bolt is open to public scrutiny?


US & ESA do. Russia is opaque and China is even worst. No one is sure if their rockets actually succeed and if so by how much.

There is a good reason why the entire nano-sat market currently is cornered by PSLV. *RELIABILITY*.

Here is the rub., Chinese MARS probe was lost with Phobos-Grunt. The launcher was a Zenit rocket. It never left earth orbit. The launch in 2011 was 2 years before ISRO's mangalyaan launch. It has been 6 years since., and even if Chinese launch today - it will not reach the Mars orbit till 2019/2020. By then Mangalyaan would be 5 year older and completing its mission.

What happened to their "big" payload capacity? Where is it?

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Re: GSLV-Mk III launch program/post-launch analysis

Postby nirav » 08 Jun 2017 02:35

^ :rotfl:

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Re: GSLV-Mk III launch program/post-launch analysis

Postby disha » 08 Jun 2017 02:41

Future:

1. Swarms of pico-/micro-/nano-/mini- satellites creating a mesh- framework for a particular purpose is going to be a reality.
2. Miniaturization is a reality. So is newer and newer avenues of space applications which create newer requirements.
3. Docking is routine. In fact., moon mission in 1969 required undocking/redocking in LTO. ISS is modular and has been assembled using many pieces. It was not launched in one go.
3.1. As Prassanasimha'ji posted., ISRO is already planning SPADEX (they also had HEX with SLV launcher, which was deemed obsolete because of its limited capability!)

New innovations and new challenges are a reality. The biggest challenge is to mine a near earth asteroid and get back the minerals. That should be the goal. And then mastering propulsion which is 10% speed of light.

The drive to bigger capacity for GEO was started in early 90s., since it was assumed that the GEO sats will always be >5 ton. Further the launch reliability was iffy., so to reduce cost - it was thought that one can piggy back another payload. That is design for >8 ton and one can have two sat of 4t launches in one campaign. Heavy payload definitely has its benefits. And it has its costs.

But the most important goal is not heavy payload., but RELIABILITY at a significant COST saving.

If I have a rocket which costs $10/pound to send it to GEO with 100% success and frequently., I will be heavily booked. Since that is 1000x cheaper than booking through the 6-tonne payload launcher.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Hari Seldon » 08 Jun 2017 03:19

disha wrote:If I have a rocket which costs $10/pound to send it to GEO with 100% success and frequently., I will be heavily booked. Since that is 1000x cheaper than booking through the 6-tonne payload launcher.


Will require SSTO + reusability for such ridiculously low costs.

Or a space elevato kinda setup.

Or energy too cheap to meter crammed into ultra-high power density - a fusion derived power pack, basically.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby SSSalvi » 08 Jun 2017 05:33

naruto wrote:
SSridhar wrote:The brochure says that expected apogee was 35973 Kms, perigee 170 Kms & inclination 21.5 deg. Though ISRO has not yet announced the orbital parameters, which is unusual, it has been reported that attained orbit has been 163 x 34 592 km and inclination was 21.537 deg.

The satellite tracking website n2yo gives the following:
Perigee: 155 kms
Apogee: 34577.8 kms
Inclination: 21.7 °
http://www.n2yo.com/satellite/?s=42747


Video shows attained velocity @947.8 sec to be 9.8 kms/sec whereas the brochure says the velocity at last stage shutdown as 10.2 kms/sec .. surely the performance is less than planned. Overall the automated system seems to have decided to perform operations 10 seconds earlier than the brochure ( which anyway is a tentative value ).
Also there are two models used to define Earth which many a times create a small confusion in calculating the Altitude. ( both are correct and give consistent results in their own system ).
Inclination is matching the planned value 21.5 deg.

-----
A few notings after going thru the thead ( situations do not allow me to read in Indian realtime and use my tools to do my maths .. 1 year old computer gone kaput + can't afford repair here in $$$ + din/raat difference etc ):

- NORAD tracks optically the objects ( even ISRO has a facility in the Lord's town ) among other methods
- Launch inclination is the rocket angle at launch time and is always brought to 0 deg after 2nd or 3rd maneuver ( in case of GTO launch from SHAR )

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Varoon Shekhar » 08 Jun 2017 06:39

Why hasn't the ISRO site reported any orbit raising? By now, 2 days after a launch, at least one is done and mentioned on the site.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby vina » 08 Jun 2017 06:47

SSSalvi wrote: Also there are two models used to define Earth which many a times create a small confusion in calculating the Altitude. ( both are correct and give consistent results in their own system ).


Interesting. Please explain.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby shravanp » 08 Jun 2017 07:31

Gurus, anybody has good hd quality images of mk3 right during liftoff? Would like to have it as wall paper. I am still not done over the euphoria.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Amber G. » 08 Jun 2017 07:51

vina wrote:
SSSalvi wrote: Also there are two models used to define Earth which many a times create a small confusion in calculating the Altitude. ( both are correct and give consistent results in their own system ).


Interesting. Please explain.

Vina et al -
Perigee (and apogee) are sometimes incorrectly (or sloppily) used by layman people - when the correct term might be 'altitude'.

The orbit is elliptical -- one of the focus is at CENTER of the earth -- and the perigee/apogee is measured from the center of the earth. This makes orbit calculation easier.

To get appox value of altitude one subtracts radius of earth from perigee -- assuming earth is a perfect sphere.

But earth is not a perfect sphere. The polar radius is smaller than equatorial radius. Thus subtracting the "average" radius will only give approximate result. One makes correction by taking oblateness of earth into account. Now one gets that distance as measured from surface (rather than center).

There are models (For example see https://en.wikipedia.org/wiki/World_Geodetic_System#WGS84) which are used to make correction due to non-spherical shape of the earth.

Hope this helps.

(For equatorial orbits the offset does not vary much .. for a polar orbit , one really have to know the latitude if you need accuracy more than 20-30 Km)

*** For those who are interested in basics ...
Once one uses ellipsoid fit (that is assumes earth is not a perfect sphere but flattened around 1/298) simple math (geometry of ellipse) gives very accurate answer. The "correction" (differences in height between the geoid (more accurate or actual value) and ellipsoid (theoretical value from above) is less than 0.1 Km ...Not important if you are doing calculation with pen and paper .. Very important if you are using GPS.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby SSSalvi » 08 Jun 2017 08:19

^
That is right.

What we call as perigee is actually an ALTITUDE from the Earth's surface when the satellite is nearest to Earth.

Now a question arises : What is meant by Earth's surface?

Depending on the user

- some take it as MSL ( we still use it extensively because SOI was referring to all heights ' from Mean Sea Level ' till a few years ago due to British Era heritage),
- Some find a average of overall globe dimensions and use it as a mean radius,
- some use a mathematical model ( Harmonics ) to describe the shape of Earth and find the Earth's dimension .. popular now a days ( due to near match with physical dimensions ) is called as SGP4 and a lot of good explanation is available in net about it. Advantage : Easy to use in computer programs

I recently ( Last month .. there was another GSLV launch ) had posted orbit parameters in another forum while someone claimed that the altitude was less than what I had ( and it was very near to pre-launch published values ) .. then after a few nok-zhoks with ' goras ' it turned out that the on line calculator that the other poster used to refer used a different model .. the difference was almost 35 kms in Perigee and Apogee ( Farthest point frpm Earth )

At this moment : for GSAT 19

n2yo website gives :
Perigee: 155.0 km
Apogee: 34,577.8 km
Inclination: 21.7 °

while http://www.satellite-calculations.com/T ... racker.htm gives:
147.8 kms and 34570.5Kms

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Varoon Shekhar » 08 Jun 2017 08:52

Some good news!

http://isro.gov.in/update/08-jun-2017/f ... ly-carried
Quote

The first orbit raising operation of GSAT-19 Satellite has been successfully carried out by LAM Engine firing for 116 sec from 14:03 hr IST on June 06, 2017.

Orbit Determination results from this LAM firing are:

Apogee X perigee height was changed to 35938 km X 172.77 km.
Inclination is 21.56 deg.
Orbital period is 10 hr 33 min.



http://isro.gov.in/update/08-jun-2017/s ... ly-carried
Quote

The second orbit raising operation of GSAT-19 Satellite has been successfully carried out by LAM Engine firing for 5538 sec from 15:44 hr IST on June 07, 2017.

Orbit Determination results from this LAM firing are:

Apogee X perigee height was changed to 35840 km X 10287 km.
Inclination is 7.02 deg.
Orbital period is 13 hr 58 min.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby vina » 08 Jun 2017 09:32

Amber G. wrote:Perigee (and apogee) are sometimes incorrectly (or sloppily) used by layman people - when the correct term might be 'altitude'

Hope this helps..


SSSalvi wrote:What we call as perigee is actually an ALTITUDE from the Earth's surface when the satellite is nearest to Earth.

Now a question arises : What is meant by Earth's surface?


Thanks AmberG and SSSalvi. While I knew that the earth is actually prolate and not a perfect sphere , I had never imagined that this could lead to "confusion" in perigee and apogee as I had assumed that would mean wrt MSL (as all other Aero related standards do, for instance even altitude when you climb a mountain is wrt. MSL) and that it was "standardised" .

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Re: GSLV-Mk III launch program/post-launch analysis

Postby vina » 08 Jun 2017 10:02

shiv wrote:The Boeing 747 - A 380 example is relevant in that Airbus felt that 747 was long in tooth and decided to put in a competitor. Boeing decided to stay out. A 380 is not doing well.

I am not sure that we are "competing". We are behind and are going to stay behind in a market that has many players who can loft heavier weights into orbit than us and private players who can do it cheaper. We are watching what others are doing and trying to catch up.

If we must look ahead we need to undercut or bypass the advantages that these players have. No point chasing them except to the extent we need for our own satellites - by the time we catch up they will be a step ahead in the game. This is true of all high-tech segments. We are not going to grab a monopoly segment of the market - which is what is needed to become a world leader.


Ah. Now we have strayed into Strategy & PissNess and more specifically into "Technology Strategy" , where I of course have the "Upper Hand" (with a vert long one at that ), so do let me expound or do "Vyakhyaanam" .

B747 vs A380 . This is a classic example of a strategy implementation (of a game theory based deterrence) of an entry barrier. It is done in all instances where 1) Fixed costs/ Entry costs are very high 2) The overall market size is limited 3) 1 and 2 together deter new entrants.

How so ? Well, it takes tremendous amount of money to develop and certify a plane of the size of A380 , the market for planes of those size is limited and so what happens, ONCE you develop it and bring it into service ? Well, for a potential new entrant into it, the incumbent costs are now SUNK costs, while for the new entrant, he has to recover full investment costs AND realise a profit. The incumbent can and WILL sell the planes at marginal cost if NEED be , and the new entrant will NEVER make a profit and wont even recover his investment.

So, for the first entrant , it guarantees, a monopoly position in that segment and decades of fat juicy profits and margins. This is exactly what Boeing did with the 747 , in the early 60s , when Boeing BET THE FARM on that plane and hence deterred competition in that segment and reigned unchallenged for 40 years, until new technology (composites and higher thrust and more efficient engines allowed twin engine planes A330, B777) allowed superior economics to a 4 engined all metal plane , and on the higher side was straddled by the A380 (with far newer tech), and hence fell between two stools.

Happens all the time in multiple industry. Is demand for a particular specialty chemical X million tons a year ?, Well, if you want to deter competition, the first entrant builds a plant of capacity 1.5 X million , they will deter any possible new entrant.

So how do you break into a market with such barriers erected (these kinds of things rely on economies of scale, the incumbent has lower costs due to economies of scale, while the entrant is sub-scale) is 1) Via technology distribution disrpution 2) Govt action /regulatory action to break economies of scale of incumbent.

1) If ISRO develops a reusable rocket plane with fundamentally different economics ie. does a disrputive innovation ( a term so beloved to VCs and other useless types like me , and so cliched) .I am not talking of Space X type, but rather more like the Paul Allen type of lofting a rocket to high altitude and launching.. as someone posted , a airfoil develops 7X it's drag as lift and far more efficient in lifting things than fitting a rocket to the Mushrraf) , it will disrupt the entire rocket launch business.

2) With existing technology & attendant economics, disrupt economies of scale. This anyway happens. The satellite launch business in NOT a competitive market , but rather protected franchises by national govt. The US wont let India launch their satellites, the Europeans wont let us launch their's neither will the Chinese nor Japanese. In fact there is an "understanding" between US , the EU and also China not to compete on price for satellite launch services.
a) So in that case, the only competitive segment is for 3 rd country / non govt launches. Here there is true price competition.
b) Market a) is allied with satellite building business, which too is again an "protected" business. (US wont allow satellite exports for launch in India).
c) In current tech . Basically put rules saying that all Indian TV broadcasts have to be India built and/or India launched satellites (all the Asian guys who lease transponders here will fall in line and buy ISRO satellites and launch from here) ..
d) Once you have a domestic market of size, you can have the volumes and economies to compete in a)

End of Vyhakyanam (OT).

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Amber G. » 08 Jun 2017 10:45

vina wrote:
Thanks AmberG and SSSalvi. While I knew that the earth is actually prolate and not a perfect sphere , I had never imagined that this could lead to "confusion" in perigee and apogee as I had assumed that would mean wrt MSL (as all other Aero related standards do, for instance even altitude when you climb a mountain is wrt. MSL) and that it was "standardised" .


Vinaji - To add some more (hope that is helpful)

To describe an orbit (generally people give six parameters regarding size, shape, inclination etc) one uses the center of the earth as reference, otherwise the calculations will be hard. For planes etc, it certainly makes sense to use MSL but not for satellites ..You want an accurate (and standard reference system) way to calculate it's position (without worrying irregularities of earth's surface).

(BTW for shape and size, standard is semi-major axis (a) and eccentricity (e) and so earth's/size and shape makes NO difference - and that's how GPS satellites calculate "their" own positions ).

Now if you use a GPS (or observe a satellite from a ground station) you have to find your own location with respect to center of the earth.

It's not only position but even velocity has some confusing part - (velocity wrt to ground or wrt to center of earth)

In practice, from ground station(s) one find's "relative position" (here altitude makes more sense) and "relative velocity" (the ground station is also moving with respect to center of earth - earth is spinning) one calculates the 6 parameters of the orbit which can be used to predict sat's future position.

Just one example, take a perfect circular orbit. Distance from center of earth is constant.. things are simple.

But the "altitude" will change.. (for polar orbits at pole it may be 30 Km less than at the equator).. worse still if you are not "exactly below" the calculation is even harder..Also note that you are moving much faster at the equator than at a pole, so even the speed of the sat will change if you are using relative velocity.

I don't even like altitude as standard as it does not help me to locate/calculate's sat's position. OTOH if I know the standard values ( orbit parameters) I can easily find the position knowing my long/latt on earth.

Hope this helps.

(I think the point is, for planes it makes sense to have altitude and ground speed as standard, for sats it- makes less sense, IMO)

***
BTW - using "average" value of radius - the error one gets is about 10-20 Km.. If you make first order of adjustment (that is assume average value of radius and flattening factor of 1/298 -- Newton used 300 I think) the error is less than a Km (or the order of 100 meters). If you use online data available you can have accuracy of about 1meter !!!

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Amber G. » 08 Jun 2017 11:24

SSSalvi wrote:^
That is right.

What we call as perigee is actually an ALTITUDE from the Earth's surface when the satellite is nearest to Earth.

Now a question arises : What is meant by Earth's surface?

Depending on the user

-
I recently ( Last month .. there was another GSLV launch ) had posted orbit parameters in another forum while someone claimed that the altitude was less than what I had ( and it was very near to pre-launch published values ) .. then after a few nok-zhoks with ' goras ' it turned out that the on line calculator that the other poster used to refer used a different model .. the difference was almost 35 kms in Perigee and Apogee ( Farthest point frpm Earth )

SSSji - Actually a few months ago (100+nano sats) )I also saw some "discrepancy" in one of the "perigee" you posted and what I calculated (calculation is simple enough - I was just using hand calculator - so I made a slight mistake) I was going to mention it then when I was putting some stuff about orbits but did not..but I digress :) ...

But this 35 Km difference "nok-zhok" looks like a plain error on the other person's part -- rather than using wrong "online" calculator.. the error is so high -- as if the model just used "average radius or "equatorial radius" wrongly .. because this is as big a discrepancy one can get!... heck one doesn't even need a calculator to come within 35Km accuracy.. IMO..

BTW Do you know if Chinese geoid data (2002?) is available or they still keep it to themselves?
Last edited by Amber G. on 08 Jun 2017 11:33, edited 1 time in total.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Singha » 08 Jun 2017 11:26

Do we use model of lam.engine on all sats? Anyone has pix and specs?

5500secs is a really long burn.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Neela » 08 Jun 2017 11:46

shiv wrote:The Boeing 747 - A 380 example is relevant in that Airbus felt that 747 was long in tooth and decided to put in a competitor. Boeing decided to stay out. A 380 is not doing well.

I am not sure that we are "competing". We are behind and are going to stay behind in a market that has many players who can loft heavier weights into orbit than us and private players who can do it cheaper. We are watching what others are doing and trying to catch up.

If we must look ahead we need to undercut or bypass the advantages that these players have. No point chasing them except to the extent we need for our own satellites - by the time we catch up they will be a step ahead in the game. This is true of all high-tech segments. We are not going to grab a monopoly segment of the market - which is what is needed to become a world leader.


Well Boeing is not sitting down idle . It is planning a extended version to increase seating to reach low 400s pax and closing the gap between A380 capacity.

Trying to compete in others ways does not obviate the need for ~10t to GTO. Just like an airline company which has mix of 20 seat turbo props to 450 seat A380s and chooses the aircraft based on the route, you need heavy lift vehicles and smaller ones.
And despite ion propulsion, the market for chemical propulsion for orbital corrections is not going to go away as the former cannot do it as quickly as the latter.
Also on miniaturization - If it gets smaller, then options will be pursued to combine functionality on satellites and this would drive the weight up. We should learn from Nokia's death.

Once a tech has been proven, the next step will always be "commoditization". Faster, cheaper, reliable and with options. The fact that ISRO is pursuing SC engines, thinking of clustering them clearly shows they serious in pursuing cheaper heavy lift capability. And ISRO's payload adaptor technology allows it to already compete in a niche area.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby SSridhar » 08 Jun 2017 12:20

Singha wrote:5500secs is a really long burn.

Usually, three LAM firings are needed to raise the perigee and reduce the inclination to place the payload into continuous visibility from Hasan and let it drift into its slot. Past history shows that 90 to 110 minutes is the order of first LAM firing, 40-50 mins for the second and ~5 mins for the third.

The LAM firing at apogee is also an out-of-plane manouevere to reduce the inclination and hence costly. Significant reduction of the inclination is achieved in the first LAM firing.

In GSAT-19's case, the first LAM would have been an in-plane perigee burn to raise the apogee.

This launch reminds me of the GSLV-F04 which put the INSAT-4CR at 168 X 34710 with 20.7deg inclination.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Singha » 08 Jun 2017 13:02

History has proven we need full spectrum caoability to be truly free of pressure. If we eschew 10t to gto a time will come when we need a lahncher for a urgent use case hut the cartel will punish us and extract tribute or reject outright.

Even if we use once in 2 yrs such a big ulv needs to ve designed and proven. The heavier configs of each launcher anyway are used sparingly....falcon9heavy has not even flown yet...vanilla falcons will launch much more

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Suraj » 08 Jun 2017 13:43

Congrats to ISRO on this accomplishment! Question to space watchers, who I hope will humor me since I'm an infrequent visitor here - why is GSAT-11 still scheduled for launch on Ariane-V next year when we have LVM3 now ? Too little lead time to set up launch schedule ?

Edit: turns out its probably a matter of mass - it's a 5.5 ton sat, the heaviest ever built in India. However they could switch the GSAT-17, which is 3.5 tons, to LVM3 .

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

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Re: GSLV-Mk III launch program/post-launch analysis

Postby symontk » 08 Jun 2017 13:45

Singha wrote:Do we use model of lam.engine on all sats? Anyone has pix and specs?

5500secs is a really long burn.


remember one of the PS4 engines in PSLV, LAM will look similar. If you think how PSLV "matured" from 450kgs GTO to 1500Kg GTO, one of the reason is the better LAM's

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Bart S » 08 Jun 2017 13:50

Suraj wrote:Congrats to ISRO on this accomplishment! Question to space watchers, who I hope will humor me since I'm an infrequent visitor here - why is GSAT-11 still scheduled for launch on Ariane-V next year when we have LVM3 now ? Too little lead time to set up launch schedule ?

Edit: turns out its probably a matter of mass - it's a 5.5 ton sat, the heaviest ever built in India. However they could switch the GSAT-17, which is 3.5 tons, to LVM3 .

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


That is correct, we don't have a productionised launch vehicle for that weight class yet.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby rahulm » 08 Jun 2017 13:52

Launches are contracted well in advance. LVM3 is still in development mode. ISRO achieved success in its maiden LVM3 launch but there is no way they are going to risk a satellite launch on a development vehicle.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Lilo » 08 Jun 2017 16:35

X-posting my post from few months back
Lilo wrote:space station ... military payloads(including payloads for impending weaponization of space) .. interplanetary probes(not the orbital insertion technology demonstration type) ... mars exploration & colonization .. moonshot & moonbase ... microgravity research ... Hubble telescope like basic astronomy & astrophysics research ...

All require reliable & cost effective & massive payload carrying rockets.

I don't get this 4 tonne to GTO is more than enough approach.Unless we want to keep on bragging about our sixth nation syndrome .

I don't want to hear that ISRO achieved this or that with a shoe string budget yay! kind of claims adnauseum. I think even folks at ISRO are tired to hear that .
Instead everyone must question why more budget is not alloted to ISRO for more bigger goals.Especially when we are going to be the 3rd largest economy in 15 years time.
It's not for H&D purpose that China is planning to raise a space station into orbit.
Has India been promised a piece of ISS real-estate to be smugly foregoing all the microgravity research in biotech & basic physics(nanotech) etc ? I don't think so.

viewtopic.php?p=2121554#p2121554

10 ton to GTO is the bare minimum with our tech levels.

The top dogs Massa , Russia Euro and China have already militarized space and going ahead will be doing boost phase intercepts on our missiles as and when needed.Only the suckers who lack launch capability to do anything about it still keep posturing publicly that the unverifiable outer space treaty still holds.We should know better.

Our predominantly missile based nuke detergent won't wash going ahead.

One can simply look at the number of classified mission payloads the US airforce ,NRO etc are lofting continuously. All are being claimed as classified "reconnaissance" payloads and their weights are not revealed - yet heavy versions of their heavy lift vehicles are used to lob them. Even the American sources guess each of these payloads may be weighing upward of 7 tons. I think they have long crossed the 10 ton mark.

ISRO needs to do the heavy lifting (pun intended) no two ways about it.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby vasu raya » 08 Jun 2017 19:29

With focus on increasing the launch frequency as stated by ISRO chief, they could take the incremental approach of converting the S200 SRBs each weighing some 30 odd tons to composites based to reduce the empty weight and add glide down wings to be reused for later missions, same with saving the engine sections of other stages, though so far a runway is missing at Sriharikota indicating no efforts in that direction

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Re: GSLV-Mk III launch program/post-launch analysis

Postby ramana » 09 Jun 2017 00:51

vasu raya, Only the Shuttle SRBs were reusable as they were made out of high strength alloy steel that could take the impact of sea surface.
Composite would shatter when it hits the sea surface. Adding glide wings to them to reduce the impact adds extra complexity. One more failure mode in the FMEA.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby disha » 09 Jun 2017 01:08

On the "10 ton to GTO capability"., I see there is a slide in narrative.

Nobody is saying we do *not* want that capability.

If India requires a giant payload capability., ISRO has-to and will deliver that giant payload capability.

And definitely not because some other nation has a big but useless payload capability and we must ape it because on this little corner of the forum we feel emasculated!

Point was and is and will always remain, to what end a launch capability should be. It boils down to two things: Reliability and Cost. For human spaceflight., it is Safety, Reliability and Cost.

---

Nobody has answered this question:

Chinese MARS probe was lost with Phobos-Grunt. The launcher was a (Russian) Zenit rocket. It never left earth orbit. The launch in 2011 was 2 years before ISRO's mangalyaan launch. It has been 6 years since., and even if Chinese launch today - it will not reach the Mars orbit till 2019/2020. By then Mangalyaan would be 5 year older and completing its mission.

What happened to their much vaunted "big" payload capacity? Where is it?


I do think that proponents of 10 ton to GTO "right now - otherwise sky will fall" do need to answer the above question.

---

I mentioned when GSLV Mk III launched successfully that now India is 10 years ahead of China. How so?

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Lilo » 09 Jun 2017 02:01

disha wrote:On the "10 ton to GTO capability"., I see there is a slide in narrative.
Nobody is saying we do *not* want that capability.
If India requires a giant payload capability., ISRO has-to and will deliver that giant payload capability.
And definitely not because some other nation has a big but useless payload capability and we must ape it because on this little corner of the forum we feel emasculated!

Point was and is and will always remain, to what end a launch capability should be. It boils down to two things: Reliability and Cost. For human spaceflight., it is Safety, Reliability and Cost.
---
Nobody has answered this question:
Chinese MARS probe was lost with Phobos-Grunt. The launcher was a (Russian) Zenit rocket. It never left earth orbit. The launch in 2011 was 2 years before ISRO's mangalyaan launch. It has been 6 years since., and even if Chinese launch today - it will not reach the Mars orbit till 2019/2020. By then Mangalyaan would be 5 year older and completing its mission.

What happened to their much vaunted "big" payload capacity? Where is it?

I do think that proponents of 10 ton to GTO "right now - otherwise sky will fall" do need to answer the above question.
---
I mentioned when GSLV Mk III launched successfully that now India is 10 years ahead of China. How so?

Disha ji,
If you dont want to address the post but rather want to address the poster then there is no point to posting.
This is BRF. Ergo any feminist can amble over and label every second post here as reflecting the poster's "fear of emasculation".
Dont bring in such stupid arguments and then claim "slide in narrative".

What's the new insights into Chinese capability in space? Ask any ISRO guy he is likely to say that Chinese are sitting pretty.
How will 10 ton to GTO materialize "right now" - will it fall from the sky ?
Who said that in first place?Twisted strawmen are just twisted strawmen.
My point was that 10 ton to GTO must be in the perspective plan as its achievable with scaling up current level of tech especially since SCE is on horizon.

A carefully brewed koolaid that ISRO's program is only for civilian purpose(like commercial sat launch etc) was in put in circulation by GoI - to tide over difficult times when sanctions and technology denial regimes were constricting our strategic programs.
Times have changed the military-strategic angle is not something taboo to discuss atleast in here.
The Raison d'être of space program is to address the military threats and opportunities space affords us.
Cost(upto a reasonable extent) and efficiency is secondary in acquiring such strategic capabilities - same with nuke sub same with nuke bomb.Strategic programs are not run with "shoe string budgets".
Disha wrote:Nobody is saying we do *not* want that capability.
If India requires a giant payload capability., ISRO has-to and will deliver that giant payload capability.
And definitely not because some other nation has a big but useless payload capability and we must ape it

^
Too much contradictory stuff - Even though its called "Space" India is not actually competing militarily in a vacumn. Just as the amount of mine shaft space has meaning only as a "relative" quantity similarly the amount of offensive/defensive military payload orbiting in space is a relative quantity.
In India's case its relative to US,China,Euro etc.
Last edited by Lilo on 09 Jun 2017 02:25, edited 1 time in total.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby nirav » 09 Jun 2017 02:24

10 tons to GTO is something that's needed and will happen,in due course of time.

The only problem is when people do some back of the envelope calculations (spreadsheet) and hate on ISRO endlessly.

The growth path of the MK3 - ULV is already established.
Exact details may not be in the public domain,yet.But it's a stated intent by ISRO.

With the CE20 only being flown once, the MK3 is still at a very nascent stage in its development cycle.Itll be a while before it reaches PSLV reliability levels. The reliability is of extreme importance as this platform and its future evolutionary variants will be responsible for our human spaceflight program.

For the moment, ISRO seems very comfortable with the solids. They will exploit their core competency in the SRB space until they achieve requisite and comparable competency and consistency in clustering,semi cryo and the cryos.

Till then if arianespace launches a few more heavier sats for us, the sky won't fall down.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Gyan » 09 Jun 2017 09:21

ISRO has already disclosed glide path to 16 tons GTO. I think it will work like this

GSLV MK-3 from 2020-2030 for 4-6 tons GTO

GSLV MK-3 with SC stage 2025-2035 6-10 tons

GSLV heavier rockets after 2030 as per requirement.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby rahulm » 09 Jun 2017 09:47

ISRO will very likely surprise us all by rapidly scaling desi launch capability.

In addition to the CE20/25 gas generator engine and stage respectively, CE 7.5 staged combustion engine we also have mastered liquid engine clustering. These 3 are building blocks.

Once SC200 is demonstrated we will have all the blocks to plug and play with mk3 until ULV comes online.

Mk3 took a long time to develop and has brought us to the inflection point from where we can scale in much shorter periods. This is why mk3 is a significant vehicle, a Pitama whose decendants will go far and beyond and, be known by different names much like the R7 Semyorka the great grand daddy of Russian launch vehicles that spawned the Sputnik, Soyuz,Luna, Vostok and Molniya.

SpaceX's stage recovery is impressive. Nice shock and awe.

ISRO has sweated blood and guts last 50 odd years. Next ten years and onwards are rewards unless a disruptive tech comes along.

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Re: GSLV-Mk III launch program/post-launch analysis

Postby Muns » 09 Jun 2017 10:28


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Re: GSLV-Mk III launch program/post-launch analysis

Postby Singha » 09 Jun 2017 12:25

can upper stage cryo stacking give benefits like a 2nd stage CE20 topped by a 3rd stage CE7.5 ? .... or the game is over and done with in the 1st stage power rating?

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Re: GSLV-Mk III launch program/post-launch analysis

Postby disha » 09 Jun 2017 12:42

Lilo'ji., no I did not personally address to you or meant to offend you. If I did unintentionally., I am sorry.

I just picked up on the '10 tons to GTO' since it is a compact nice phrase.

My problem is that I am sensitive to the statement on "bigger payload hence better" when time and history has proven again and again that it is not the case. It is interesting that the "bigger payload hence better space program" and by corollary India is behind is a statement that never goes away - we listened to that in 1993 and 25 years later we still have to listen to it.

At this point we must admit that "bigger payload hence better space program" is not a completely true statement. Or put it this way., a country's space program cannot be pigeon-holed into just one parameter called "big payload".

Once we get out of that mindset., we see several options open up before us. Like RLV, ULV, TSTO, SPADEX, iON thrusters are to just name a few.

For example., when high temperature superconductivity was discovered in 80s., concept of launching a space cargo using EMALS was immediately imagined. Here is what ISRO can do., investigate EMALS to launch space cargo. The same EMALS can be used for navy or for Indian railways., in a different form.

But if we ape US or Cheen., then we will lose sight of next innovation. US has a large private industry and an industrial base to sustain innovation in space by private ventures., India is not there yet. Hence the innovation for ISRO has to come from within. And to me., it will come if it looks at US/Cheen and asks "what could I have done different"?

And yes, the above qstn has been asked and the answer is Chandrayaan and Mangalyaan and AstroSat and the world's largest fleet of EO sats under a single agency.

I rest my case there.


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