Indian Space Program: News & Discussion - Sept 2016

shiv · Post by **shiv** » 09 Sep 2016 12:39

juvva wrote:^Around 44:15 in the launch video, I noticed, what looks like loss of data, the altitude and velocity plots stopped updating for a few seconds.

Drinks intarval

Venu · Post by **Venu** » 09 Sep 2016 12:48

Suraj wrote: Congrats to the ISRO! In the video at 28:47, for the first time I see shock diamonds / Mach rings forming out of the boosters . I don't recall seeing these before. Cool visuals!

Not new, they can be observed in the previous flights as well.

srin · Post by **srin** » 09 Sep 2016 12:49

This was the first time I noticed the "cryogenic engine authorisation" at 274.1 seconds. What's the purpose ? No other engine ignition requires authorisation ...

thammu · Post by **thammu** » 09 Sep 2016 12:54

SSridhar wrote
...PSLV puts the payloads into a polar orbit which is at 90deg to the GSO and at altitudes of only ~700 Kms....

Sorry, what I meant was -- GSLV can release all the polar load at ~700 Kms, and then go ahead to GTO. Or carry more tonnage to 700 kms than a PSLV.

juvva · Post by **juvva** » 09 Sep 2016 13:46

prasannasimha wrote:
juvva wrote:^Around 44:15 in the launch video, I noticed, what looks like loss of data, the altitude and velocity plots stopped updating for a few seconds.
That is jsut a recording glitch we could see it continuously when watching it live

I don't think so, remember seeing it during the live broadcast also.

SSridhar · Post by **SSridhar** » 09 Sep 2016 13:56

juvva wrote:I don't think so, remember seeing it during the live broadcast also.

It has happened in some earlier flights also. Probably a glitch in communication between Brunei ISTRAC station & SDSC.

SSridhar · Post by **SSridhar** » 09 Sep 2016 14:10

thammu wrote:Sorry, what I meant was -- GSLV can release all the polar load at ~700 Kms, and then go ahead to GTO. Or carry more tonnage to 700 kms than a PSLV.

The orbital requirements are vastly different. If you look at the flight profile of GSLV here, you will find that the satellite is released at an altitude of 213.51 Kms with a velocity of ~10 Kms/s. while PSLV's profile is that the fourth stage engine cuts-off at 650 Kms (followed by satellite release) with a velocity of ~ 7.5 Kms/s. The GSLV is a shallow launch compared to PSLV. GSLV is an elliptic orbit with an apogee of 36000 Kms and a perigee of 170 Kms and nearly west-to-east, while PSLV payloads are in circular orbit of ~700 Kms north-south. GTO flights are later circularized by LAM firings to be at 36000 Kms but initial injection of payload is at 170 Kms where GSLV mission ends.

SSridhar · Post by **SSridhar** » 09 Sep 2016 14:29

Just wanted to highlight the precision with which the GTO orbit has been achieved :

INSAT-3DR satellite is now orbiting the Earth with a perigee (nearest point to Earth) of 169.76 km and an apogee (farthest point to Earth) of 36,080.5 km with an orbital inclination of 20.62 deg with respect to the equator.

The Brochure talks of targetted perigee of 170 ± 5 Kms, apogee 35975 ± 675 Kms and inclination 20.61 ± 0.1 deg (though the F05 brochure does not mention the variation for inclination, I have used the figure from earlier launches)

thammu · Post by **thammu** » 09 Sep 2016 15:11

SSridhar wrote:The orbital requirements are vastly different....

Thanks. Understood now.

prasannasimha · Post by **prasannasimha** » 09 Sep 2016 17:18

Changing orbital planes requires a huge delta V budget Turning a rocket through 90 degrees will incur a huge amount of fuel budget it may not be economically and practically feasible in the commercial sense. They rotate the rocket in certain small angles during multiple satellite launches but these are just orientation changes but the basic path of the spacecraft remains the same.

hanumadu · Post by **hanumadu** » 09 Sep 2016 17:35

vina wrote:ISRO is talking about reuse of stages like SpaceX and also multiple restart capabilities of their cryogenic engines so that they can be used for deep space missions and also to fly satellites directly to GEO and not just inject them into GTO.

Well, it looks like the ULA with their new Vulcan launcher is approaching this a bit differently. For one ,they are bringing back via mid air capture, just the engine of the booster and are getting rid of the hydrazine and helium and batteries by having an IC engine in the cryogenic upperstage and pretty much have a cryogenic engine that is probably usable for months together allowing them to do all sorts of stuff.

Maybe the ULA approach seems easier to achieve for ISRO within a shorter time than trying the space X kind of recovery of stage via a flyback and vertical landing (which is complex, failure prone and has a penalty in payload carried.), maybe, we can fix parasails on the engines shed from the stage and fly them to land in northern sri lanka instead of trying to capture it mid air via helicopter like ULA.

IIRC, I remember you saying that the RLV is the harder and time consuming option and the spaceX way is not hi fi, but quicker and easily achievable. Now that ISRO Is doing the space X thing, you are saying its too complex and want them to follow yet another approach. They may very well do it, but the savings of just saving the engine may not be much.

Varoon Shekhar · Post by **Varoon Shekhar** » 09 Sep 2016 19:13

Shekhar Gupta in rediff has made a sweeping remark about the PSLV, in a general attack on India's acceptance of mediocrity. "The world has moved on", with respect to the PSLV, but what does that have to with the particularity and value of the PSLV? If Gupta were making an informed technical criticism about the various stages of the rocket, that would be fine. This is just a mindless jibe, with no acknowledgement of the achievements of the vehicle for specific satellites and orbits. And for launching 10 or 20 satellites at once. Or a Mars mission.

rgosain · Post by **rgosain** » 09 Sep 2016 21:47

Varoon Shekhar wrote:Shekhar Gupta in rediff has made a sweeping remark about the PSLV, in a general attack on India's acceptance of mediocrity. "The world has moved on", with respect to the PSLV, but what does that have to with the particularity and value of the PSLV? If Gupta were making an informed technical criticism about the various stages of the rocket, that would be fine. This is just a mindless jibe, with no acknowledgement of the achievements of the vehicle for specific satellites and orbits. And for launching 10 or 20 satellites at once. Or a Mars mission.

Maybe it is Rediff and its esteemed writer who needs to move on from spraying its readers with this level of uninformed manure. If ever a writer of an article needed to be reminded of Mark twain's statement about keeping one's mouth shut and not leaving the world in doubt about the ignorance and stupidity of his output, it is this guy.

So Proton-Soyuz (1964), Delta, Titan (1960-1970 s vintage), Zenit, even space-X's Falcon has its origins in the 1980.. perhaps Gupta should tell them all to move on.

Bheeshma · Post by **Bheeshma** » 09 Sep 2016 22:16

Isn't this shekat coup-ta of the coup against mickey mouse singh fame?

Mollick.R · Post by **Mollick.R** » 10 Sep 2016 02:10

A novice question

The cryo stage of last GSLV vehicle was having a blackish appearance. I think previously it used to different (smooth white finish). Read somewhere this was a special material or painting developed by ISRO for cooling the cryo fuel.

If any gurus of forum can explain a bit more.

Amber G. · Post by **Amber G.** » 10 Sep 2016 05:27

^^^"White "finish" can reflect radiation (from sun) and can keep the temperature low. Theoretically/ideally we want good paint reflecting most of the radiation and can keep the temp around/below 50K ( the freezing point of oxygen). But like everything else nothing is simple and process is complex. I do not know much about this wrt to ISRO so have to ask around but meanwhile this (from nasa document) may give some background..
Cryogenic Selective Surfaces

NIAC study we discovered a novel coating we call “Solar White” that, when used in deep space, is predicted to reflect more than 99.9% of the sun’s energy. We have shown analytically that a sphere covered with a 10 mm thick coating of Solar White and located far from the Earth and at 1 Astronomical Unit from the Sun can achieve a steady state temperature below 50 K, the freezing point of oxygen. The ramifications of such a coating are broad and significant, ranging from enabling long-term cryogenic storage to allowing passive high temperature superconductor operation in space. However, the development of these coatings is only at a theoretical modeling stage. The next two significant steps required to advance this breakthrough technology are to fabricate these coatings and test their performance. Construction of rigid versions of the coatings may be difficult...<snip> ,

-

vina · Post by **vina** » 10 Sep 2016 10:33

hanumadu wrote:They may very well do it, but the savings of just saving the engine may not be much.

The rationale for the ULA reusing just the engine block is this. In a launch vehicle, by value, approx 75% is the lower stage and out of which 70% of value is the engines. So net net , by bring back just the engine block of the lower stages alone and reusing it,you are reusing 50% of the value of the vehicle.

The easiest and quickest way to reuse for ISRO might be what ULA is trying to do and not what Space X and Blue Origin are trying to by flying back /landing entire stages precisely at sea on a barge, which is a much tougher engineering problem. Plucking it out of the sky via a helicopter is far easier.

hanumadu · Post by **hanumadu** » 10 Sep 2016 10:50

vina wrote:
hanumadu wrote:They may very well do it, but the savings of just saving the engine may not be much.
The rationale for the ULA reusing just the engine block is this. In a launch vehicle, by value, approx 75% is the lower stage and out of which 70% of value is the engines. So net net , by bring back just the engine block of the lower stages alone and reusing it,you are reusing 50% of the value of the vehicle.

The easiest and quickest way to reuse for ISRO might be what ULA is trying to do and not what Space X and Blue Origin are trying to by flying back /landing entire stages precisely at sea on a barge, which is a much tougher engineering problem. Plucking it out of the sky via a helicopter is far easier.

I thought the rationale of RLV was to save the upper stage as avionics was the most expensive part.

prasannasimha · Post by **prasannasimha** » 10 Sep 2016 18:03

^ the cryo stage always had a black cover. They keep a thermofoam cover over various parts of all the stages which are the white shards that fall off when the vehicle launches

abhik · Post by **abhik** » 10 Sep 2016 18:14

Pretty sure that the engines are the most expensive part (at least in liquid fueled rockets). And I don't think anybody (including SpaceX) has any concrete plans to bring back the upper stage in the near future.
As far as ULA's proposal to reuse just the engines by "snatching" it from mid-air being easier than SpaceX's approach, It's just at PPT-giri stage and might never see the light of day.

vina · Post by **vina** » 10 Sep 2016 18:31

As far as ULA's proposal to reuse just the engines by "snatching" it from mid-air being easier than SpaceX's approach, It's just at PPT-giri stage and might never see the light of day.

Not true. ULA is just repositioning something that has been used for a LOOONG time. In the Atlas series, they had something called Stage and a Half , where the boosters (which are attached to a common stage) fall off after providing thrust, while the sustainers continue. And the "balloon" tank structure of the Atlas to this day remains the most efficient mass fraction for a tank despite all the advances in materials and the balloon tank is just a stainless steel structure.

In addition, what ULA is repositioning is a very old, well used (but now obsolete thing, since film cameras from spy satellites dont need to be returned to earth) system called Mid Air Retrieval, which now has capacity do it for upto 10 tons.

So ULA is just reaching back deep into it's own heritage and positioning well proven systems that worked in the past. No major new fundamental R&D required like landing a full stage vertically on a postage sized barge in the middle of a heaving ocean .
Check out this legacy footage

Gyan · Post by **Gyan** » 10 Sep 2016 20:35

There is interesting talk by Mr. Somnath of ISRO at https://www.youtube.com/watch?v=iHgn5m139uA

Does someone have access to clear pictures of the slides. There is huge lot of info inthe slides which has been released for the first time by ISRO in public domain. The Camera work in this video seems to be very poor.

dhiraj · Post by **dhiraj** » 10 Sep 2016 22:37

http://www.isro.gov.in/gslv-f05-insat-3 ... lift-video

GSLV-F05 Lift off Video

prasannasimha · Post by **prasannasimha** » 10 Sep 2016 23:33

Capturing a small film roll and capturing an engine may be pretty different in requirements . In fact this was much older they used to pick up and drop mail using a hook system much before this on various islands off the coast of Britain

Hitesh · Post by **Hitesh** » 11 Sep 2016 05:12

How long is the life span of the engine being used for the rockets? Remember they are exposed to extremely high heat and g-forces that you cannot really trust the structural integrity of the engine. You have to keep testing the engine like 100 times to declare that it is safe for being reusable. The problem with that approach, it is a very costly approach to test.

Why can't you just mass manufacture the engine and the parts that go with it and use extreme precision assembly? That will lower the costs drastically. If you use a handmade custom made approach, it is very expensive in the long run.

If I was ULA or SpaceX, I would create a rocket that could launch anywhere from 2 ton to 10 ton to polar orbit or GTO orbit using a mixture of add on boosters depending on the configuration of the payload or create a line of rocket with standard payload rackets that can accommodate a number of satellites and just offer tickets for rides. I am guessing that approach would allow such a rocket to be mass manufactured and lower the cost drastically.

Gyan · Post by **Gyan** » 11 Sep 2016 16:48

Gyan wrote:There is interesting talk by Mr. Somnath of ISRO at https://www.youtube.com/watch?v=iHgn5m139uA

Does someone have access to clear pictures of the slides. There is huge lot of info inthe slides which has been released for the first time by ISRO in public domain. The Camera work in this video seems to be very poor.

Cross post from a friendly forum, Can the experts comment, whether this info is correct?

I was trying to read the slides by busting my eyes. Some information and guess work is as follows:-

Basically the lecture is on theme that with Semi Cryo engine being achieved next year, we have all the building blocks of heavy engines. The possible configuration being discusse are variants of GSLV Mark-3. GSLV Mark-3 will itself carry 4tons (?) to GTO. Its further variant would be modified first stage which will consist of Single SC200 as core stage and two enhanced solid booster S250 as strap ons. The Upper stage will remain as Cryo Engine CE20/C27. This rocket may have a launch capacity to GTO of 6tons (?). Further modification will be to add a Cryo stage in middle consisting of two CE20/C27 engines. This rocket may have a launch capacity to GTO of 10tons (?).

The another line which will be pursued would be clustering 5 Semi Cryo 200 stages which is likely to happen/be tested around 2024 and will be called SC500. This HLV will consist of first stage of SC500 and CE20/C25 as upper stage. This rocket may have a launch capacity to GTO of 6tons (?).Its further variant would be modified first stage which will consist of clustered SC500 as core stage and two enhanced solid booster S250 as strap ons. The Upper stage will remain as Cryo Engine CE20/C27. This rocket may have a launch capacity to GTO of 8tons (?). Further modification will be modified first stage which will consist of clustered SC500 as core stage and four clustered SC500 as strap ons. This rocket may have a launch capacity to GTO of 12tons (?).

While Simultaneously ION engines are being pursued for satellites which will reduce their weight by half. So the heavy variety of Indian HLV would be able to launch a satellite that would equivalent to 24 tons satellite of today (apart from natural progression and sophistication of electronics).

prashanth · Post by **prashanth** » 11 Sep 2016 18:29

dhiraj wrote:http://www.isro.gov.in/gslv-f05-insat-3 ... lift-video

GSLV-F05 Lift off Video

Thanks for posting. Can observe solid booster burnout (2:10) and strap-on burnouts (2:48).

abhik · Post by **abhik** » 11 Sep 2016 18:55

Gyan wrote:
Gyan wrote:There is interesting talk by Mr. Somnath of ISRO at https://www.youtube.com/watch?v=iHgn5m139uA

...
Cross post from a friendly forum, Can the experts comment, whether this info is correct?

...

Some of those payload numbers are way off (or at least I hope they are). An SC500 lower stage with 5 SCE200 clustered engines would make the launch vehicle comparable (but heavier and more powerful) to the SpaceX Falcon9. 6t to GTO should be achievable, even with first stage reusability. Adding two S250s boosters will increase the weight of the launch vehicle to 1,100-1,200t, so 8t to GTO seems rather low. On the other hand a SC500 with 4 similar boosters will a close to 3,000t monster, payload to GTO should be at least 40-50t.

Gyan · Post by **Gyan** » 11 Sep 2016 23:40

Have a look at the video and see what you can make out. Perhaps we might get a better estimate of figures

Amber G. · Post by **Amber G.** » 12 Sep 2016 01:27

Gyan wrote:There is interesting talk by Mr. Somnath of ISRO at https://www.youtube.com/watch?v=iHgn5m139uA

and ..

dhiraj wrote:http://www.isro.gov.in/gslv-f05-insat-3 ... lift-video
GSLV-F05 Lift off Video

Thanks for posting the video.. was fun to watch specially since our family got to enjoy zero-g ride in "vomit comet" recently.
(certainly worth the experience -- explaining physics

and seeing things behave as they should)

SriKumar · Post by **SriKumar** » 12 Sep 2016 08:15

prashanth wrote:
dhiraj wrote:http://www.isro.gov.in/gslv-f05-insat-3 ... lift-video

GSLV-F05 Lift off Video

THis video has a continuous call-out 'yaw normal' for the first several seconds of launch. I've not heard this anywhere except for the RLV launch where the RLV- a non-cylinder, stood exposed to atmosphere. Any reason why this particular craft needed to be checked for yaw (relative to PSLVs and earlier GSLVs)...where yaw was not checked this carefully.

prasannasimha · Post by **prasannasimha** » 12 Sep 2016 09:12

The rocket was performing a yaw maneuver at that time and that was being called out.

SriKumar · Post by **SriKumar** » 12 Sep 2016 09:54

Any links that given any details on this? The call-out started at about 4 seconds after it lifted off.
Atleast visually, the trajectory did not seem that different from other rocket launches this early in the launch.

prashanth · Post by **prashanth** » 12 Sep 2016 11:36

abhik wrote:
Gyan wrote: Cross post from a friendly forum, Can the experts comment, whether this info is correct?
Some of those payload numbers are way off (or at least I hope they are). An SC500 lower stage with 5 SCE200 clustered engines would make the launch vehicle comparable (but heavier and more powerful) to the SpaceX Falcon9. 6t to GTO should be achievable, even with first stage reusability. Adding two S250s boosters will increase the weight of the launch vehicle to 1,100-1,200t, so 8t to GTO seems rather low. On the other hand a SC500 with 4 similar boosters will a close to 3,000t monster, payload to GTO should be at least 40-50t.

All of these are possible with the development of SC200 engine. A significant part of presentation contained slides showing boosters and stages made of SC200, individually or in clusters. No wonder they are pursuing this engine at full speed and expect to test the first prototype within a year from now.
Once mastered, they will replace L110 with a semi-cryo stage in LVM3. This increases payload capacity from 4T to 6T, and removes the necessity of toxic hypergolic fuels.
Using the same reason, what about PSLV and GSLV MK2 then? Will be sad if they discontinue PSLV. This vehicle gave ISRO the prestige they have today.
PS: Mr. Somnath also reveals that human rated vehicles would not have solid boosters, in future.

vina · Post by **vina** » 12 Sep 2016 13:52

Its further variant would be modified first stage which will consist of Single SC200 as core stage and two enhanced solid booster S250 as strap ons. The Upper stage will remain as Cryo Engine CE20/C27. This rocket may have a launch capacity to GTO of 6tons (?)

This is a product strategy that makes sense in the 80s, but not in a world where you have everyone talking of reuse and rolling out timelines and product plans.

SpaceX, Blue Origin, ULA and Ariane are all talking re-use. In fact, Ariane's concept is strikingly similar to ULA's . Check out Adeline .

ISRO needs to let go with it's fascination of large solids for base config in a launcher family. That should be reserved for heavy lift booster versions only. The base config should have enough oomph form it's liquid lower stages (with reuse /recover) to put a 5 Ton to GTO orbit. Cluster two of those SC200 into the L110 instead of the WeakAsses and that you will have a very efficient 2 stage to orbit vehicle of 5 ton GTO.

Gyan · Post by **Gyan** » 12 Sep 2016 13:59

In the video, at one point there was a statement to the effect that these stages are inherently reusable. (So whether to recover them or not will be considered on cost benefit ratio)

Gyan · Post by **Gyan** » 12 Sep 2016 14:01

I think SSalvi was connected to ISRO. Can admins contact him and ask him if it is possible to get better copies / view of slides? After all ISRO wants to put out this info.

Gyan · Post by **Gyan** » 12 Sep 2016 15:05

Corrected on basis of some internet surfing:-

The another line which will be pursued would be clustering 5 Semi Cryo 200 stages which is likely to happen/be tested around 2024 and will be called SC500. This HLV will consist of first stage of SC500 and CE20/C27 as upper stage. This rocket may have a launch capacity to GTO of 8tons (?).Its further variant would be modified first stage which will consist of clustered SC500 as core stage and two enhanced solid booster S250 as strap ons. The Upper stage will remain as Cryo Engine CE20/C27. This rocket may have a launch capacity to GTO of 10tons (?). Further modification will be modified first stage which will consist of clustered SC500 as core stage and two clustered SC500 as strap ons. This rocket may have a launch capacity to GTO of 25 tons (?).

symontk · Post by **symontk** » 12 Sep 2016 18:08

prasannasimha wrote:The rocket was performing a yaw maneuver at that time and that was being called out.

Ability to execute yaw means that ISRO have increased confidence on the vehicle. Yaw is important for all equatorial launches, to deliver heavier payloads, otherwise the LAM have to do more job on that. It also refers to better control given by the launch vehicle

dhiraj · Post by **dhiraj** » 12 Sep 2016 19:39

disha wrote:
dhiraj wrote:Hopefully we have a 65 m, 2*S250 SRBs, 2 MN Semi - cryo core , 2* C-25 vehicle with 10 tonne GTO capacity within next 10 yr feasible...

http://www.business-standard.com/articl ... 575_1.html
And what will we do with such a monstrosity for commercial applications? Just curious.

GSAT-11 to be launched next year through Ariane is already 5.6 tonne. Who knows the future requirement.

Hopefully many may have already read it, still sharing (good read)
http://www.frontline.in/static/html/fl2 ... 404300.htm