Indian Space Program: News & Discussion - Sept 2016

SSSalvi · Post by **SSSalvi** » 17 Feb 2017 11:26

Some prelim display of satellite release Geography:

from unfinished post at

http://indiaspaceactivity.blogspot.com/ ... es-on.html

Amber G. · Post by **Amber G.** » 17 Feb 2017 11:40

On a different note., I do want to point out that MIRV and launching multi-sats are not too dissimilar. Yes., different calculations go in each - but if you can inject a projectile into a precise orbit., you as well have the capability to inject projectile into a specific earth bound trajectory. And to that, you do point out the mastery in navigational, inertial guidance and rocket propulsions (and the algorithms to manage that) is what is rightly seen as capability. And the comparison ends there.

IMHO:

On the surface MIRV and launching multi-sats may not look "too dissimilar".. but I think a critical point is missed..

The preciseness need to inject projectiles into "specific earth orbit" is qualitatively or quantitatively is NOT (IMHO) similar. It is NOT the preciseness needed to, say, send Mangalyaan to Mars (cause slight miscalculation will make it a failure). You don't need (or even desire) any PARTICULAR orbit for any given satellite. This is VERY different for MIRV where you need each projectile to follow a VERY specific path.

Again, point is, for MIRV you need precise orbit .. exact path wrt to earth. NOT true for these nano-satallites..you need delta-V in right ball figure.. and inclination to equator in right window...In fact my guess is that precise orbit of any given projectile - wrt to earth's landmark (anywhere close to preciseness needed for say a Mangalyaan or a MIRV) is not the critical issue here----sure you want to orbit the earth and you want to make sure the perturbation due to earth's oblateness make it wobble with omega=360/year..so that you are sure that there is daylight for the camera but you really don't care exact spot (above a certain physical landmark on earth) that drone will end up any given predefined time.

To make it more clear - For multi-sats, If I know my rocket's altitude (height), velocity, and latitude (without knowing longitude, so I don't know what city lies below) I can a successful pushing of the nanos..obviously this is not sufficient for MIRV types..

Point I am making is not trivial.. hope that helps.

Amber G. · Post by **Amber G.** » 17 Feb 2017 11:50

SSSalvi wrote:Some prelim display of satellite release Geography:

from unfinished post at

http://indiaspaceactivity.blogspot.com/ ... es-on.html

Thanks. Will wait to read. Let me know if my assumption that all satallites (except obviously INS1A etc) ejected later are sun synchronous. Thanks.

amit · Post by **amit** » 17 Feb 2017 12:15

On a lighter note. Karma is a ba**ch!

juvva · Post by **juvva** » 17 Feb 2017 13:30

Final test of CUS before flight, on friday.....

http://www.newindianexpress.com/states/ ... 71170.html

Full duration flight test of GSLV’s cryogenic upper stage tomorrow
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“The performance of the engine at high altitude during the test was satisfactory and Friday’s test would be the last in the series before going for an actual rocket launch,” he said and added, “Already, earth-storable liquid core stage (L110) and solid strap-on-motors (S200) have been integrated and reached Sriharikota. C25 engine activity and integration is progressing in IPRC and should be ready for dispatch in couple of weeks.”

Gyan · Post by **Gyan** » 17 Feb 2017 16:13

Note - How quickly a successful ground test translates into test flight with ISRO

hnair · Post by **hnair** » 17 Feb 2017 16:17

amit wrote:On a lighter note. Karma is a ba**ch!

a tiny little whatsapp group of old school chums had something to do with this current cartoon, as well as that memorable swamping of NYT with 1000s of chaste malayalam script ghalis much to bewilderment of the Carrie Bradshaws and Truman Capotes that usually comment

Never forget

rsingh · Post by **rsingh** » 17 Feb 2017 19:30

disha wrote:^It is Multiple Independently Release Sats (MIRS) except the sats did not come back immediately and were no vehicles. And there in ends the conversation.

ISRO is a civilian space agency dedicated for peaceful exploration of space for the benefit of the humankind. Rest are transferred out. Like APJ Kalam.

PS: Launching a sat at a precise orbit, inclination and into a precise point is difficult than a ballistic shell, where the shells are injected at a precise trajectory, inclination into a precise box.

Like your arguments because most of the time these are backed by solid reasoning and logics (and science), but we can not be that sure in this case. ISRO will be atoot-ang of any sat- kill tech that we will have (or we have).salam

SSSalvi · Post by **SSSalvi** » 17 Feb 2017 19:43

@ AmberG

ALL sats are currently in SunSynch orbit ( 98 minute/ 15.2 orbits per day ).

If necessary then they will have to change the orbit.

SSSalvi · Post by **SSSalvi** » 17 Feb 2017 19:49

A question to vehicle experts:

Earlier PSLV launched sats even at 900 kms orbit @ equator.

This flight was a slow riser ... attained 500 kms @ about -20 deg Lat.

Is it due to vehicle constraint or deliberate?

Varoon Shekhar · Post by **Varoon Shekhar** » 17 Feb 2017 20:03

Does anyone know what will be the effect of the failure of the atomic clocks onboard IRNSS-1A, for the system as a whole? Will the area under coverage be reduced?

SSSalvi · Post by **SSSalvi** » 17 Feb 2017 20:06

It seems that ISRO data station BHARATI at Antarctic does not have a TTC ( S Band ) capability.

Otherwise that was a better choice to continue launch Telemetry after MAU.

( OR it could be because it has a only store and forward capability .. and not real time feedback capability )

rsingh · Post by **rsingh** » 17 Feb 2017 21:27

https://www.youtube.com/watch?v=2wps9XzF9us

Lot of usual shouting by anchor but there is one of ISRO scientist giving lots of tit-bits which were not publicised. It is in Hindi.
IST is not Indian Standard Time but Isro Standard Time.

Rishi Verma · Post by **Rishi Verma** » 17 Feb 2017 22:45

SSSJi, can you roughly tell where the empty C37 piece starts de-orbiting, by which mechanism does it fall back and burn up? Does it take less than a full orbit or several orbits to enter back into "atmosphere"? Thanks.

Amber G. · Post by **Amber G.** » 18 Feb 2017 01:11

SSSalvi wrote:A question to vehicle experts:

Earlier PSLV launched sats even at 900 kms orbit @ equator.

This flight was a slow riser ... attained 500 kms @ about -20 deg Lat.

Is it due to vehicle constraint or deliberate?

Not vehicle expert but can make an educated guess..

As you know, inclination of the orbit is carefully chosen to make sure the sats remain sun synchronous... This depends on altitude of the sats. Classical Newton's perturbation gives the precession speed proportional to J_2 (Oblateness constant), cos (i) (i= inclination), and inversely to the square of latus rectum (which is almost same a radius for near circular orbits)..In rough back of the envelop calculations.. cos (i) is proportional to (a)^7/2. (about .00008 times a^7/2 for earth when a is measured in Km's) ..

Most of such sats remain within 500-900 Km range for circular orbits (elliptical orbits are possible for higher altitude).. and latitude (and altitude) where push comes is demanded by such considerations and I guess must be deliberate.

krishGo · Post by **krishGo** » 18 Feb 2017 03:33

SSSalvi wrote:A question to vehicle experts:

Earlier PSLV launched sats even at 900 kms orbit @ equator.

This flight was a slow riser ... attained 500 kms @ about -20 deg Lat.

Is it due to vehicle constraint or deliberate?

It depends on the flight profile. Some examples from the launch broadcasts:

1. PSLVC-30 - Launched Astrosat into ~ 650 x 650 km near equatorial orbit

2. PSLV C-C311 /32 / C33 - Launched IRNSS into ~ 250 X 20,000 km GTO -

3. PSLV C34 - Polar circular orbit of 500 kms

Amber G. · Post by **Amber G.** » 18 Feb 2017 04:34

Varoon Shekhar wrote:Does anyone know what will be the effect of the failure of the atomic clocks onboard IRNSS-1A, for the system as a whole? Will the area under coverage be reduced?

I may not understand what exactly you mean by "effect" but let me point a few things here:
- With good/fast software, and communications with other reference sats (ground stations), I believe it is possible to calibrate errors and some usages can be found. (In theory if you have 4+ other stations which are accurate, you may be able use math so that IRNSS is not completely useless. I obviously do not know the effort involved and optimization (does new clocks cost less ?).. ityadi. Also if not *all* the clocks failed and backups are working.. system can limp along.

(For example my GPS has a quartz clock -- no where as precise as atomic clocks - but I can turn it into a much accurate (closer to an "atomic clock" ) if I can access 4-5 good sats with reference atomic clocks and my GPS has fast cpu and I if I can program it for this)

Of course, some with more background of IRNSS and type of clocks they are using..and the type of failure(s) and if there are there backups etc.. can give more detailed answer (I believe, but I may be wrong, the culprits are rubidium devices - which are less accurate than hydrogen masers )..
Added later - googling produced this:

With the failure of all three clocks – one primary and two backups – onboard IRNSS 1A, Kumar has said a replacement satellite, 1H, will be launched in the second half of 2017. It is unclear what caused the failure, although the issue is neither new nor likely to be unique. ..... Neither ESA nor ISRO have declared their respective constellations ineffective as a result. The IRNSS should be back to normal with the launch of 1H (for ESA ... hydrogen maser clock that failed has managed to restart itself but .. ISRO is also attempting to restart its clocks. Until such time, Kumar said the constellation will continue to work normally while the 1A provides fuzzy, imprecise measurements.

sudeepj · Post by **sudeepj** » 18 Feb 2017 05:25

Varoon Shekhar wrote:Does anyone know what will be the effect of the failure of the atomic clocks onboard IRNSS-1A, for the system as a whole? Will the area under coverage be reduced?

That Satellite will not be usable for positioning. That it cant be used will be indicated by a bit in the broadcasted data. It will be replaced by another kept in stock for such contingencies. It will have some effect in reducing the availability and coverage at the extremities of the coverage area.

Amber G. · Post by **Amber G.** » 18 Feb 2017 06:07

Meanwhile ISRO has a new fan - Elon Musk .. who tweeted Yeah, awesome achievement by ISRO. Very impressive!

SpaceX and ISRO are competitors of sorts in the business of commercial satellite launches.

In other tweets - he also was sort of bragging of his recent news - "SpaceX Will Fly a Rocket Back to Earth in Broad Daylight This Weekend" (ISRO does not use reusable rockets yet)

disha · Post by **disha** » 18 Feb 2017 08:10

KrishGo., thanks for the photos., answers SSSalvi's qstn. I did not have the photos but the answer remains the same - the flight profile is chosen for the mission. Some sats want to be at 800 km orbit and some sats in lower orbit etc. Note that two launches back PSLV launched two sats in different orbits.

In the C37 launch., after PS4 cutoff <- note the keyword 'cutoff' - the C37-PS4 stage will be at a higher orbit than the launched satellites and will stay there for 10 or so orbits before being "passivated" and brought back into a degenerate orbit. Hence for that 10 orbits., ISRO has a PS4-C37 satellite

PS4 (or for that matter all last stages of PSLV/GSLV Mk1/2/3) has extra fuel to compensate for any lower stage underperformance. The goal for all space launchers is reliability, accuracy and not efficiency! Particularly the cost of fuel is minuscule and if carrying extra fuel to compensate for any contingencies improves reliability then it is par for the course.

I am glad that ISRO is experimenting with PS4 stage as a satellite option. Attach four Solar panels and furlable antennas to that stage and it can become a space antenna. It already has fuel for orbit keeping and also powerful programmable electronics (with battery backup)! In short, ISRO can create its own deep space network!

---

AmberG., we all agree that Mian Musk is awesome and I have a Tesla parked in my garage. However please be careful of #mediapimps since they are now trying to set up "SpaceX as a competitor to ISRO" and trying to get Indians dhoti-shiver.

Here is one comment from a #mediapimp

Though ISRO too is developing its own reusable technology, it might not match the pace of SpaceX.

I think all the awesomeness of Mian Musk can be discussed in the international space discussion thread.

On the issue of MIRV vs. Multi-Sat launch., we can agree to disagree - it is a question & debate of slicing a hair longitudinally first and then latitudinally or slicing it latitudinally first and then longitudinally to get the best 'hair splitting' result. But if you get a chance, do talk to a real 'missile man' like the people who manned minuteman missiles on how targets are acquired and how the missiles are launched. And this we can take it up in missile thread.

arun · Post by **arun** » 18 Feb 2017 14:32

ISRO Press Release.

1.Cryogenic stage designated as C25 was tested for a flight duration of 640 seconds.

2.This Stage test marks a significant milestone as it is the last in series of engine and stage development hot tests before the first development flight of GSLV MkIII.

3.First development flight of GSLV MkIII-D1 targeted for April 2017.

Below linked press release has pictures and a video:

ISRO Successfully Tests its Cryogenic Stage (C25) for GSLV MkIII for the Flight Duration

arun · Post by **arun** » 18 Feb 2017 14:54

Now waiting for DRDO to successfully conclude the K4 launch.

sooraj · Post by **sooraj** » 18 Feb 2017 16:33

US military signs agreement with Sky and Space Global

The agreement with the US Department of Defence is for the provision of space situational awareness services and real time information to ensure the safety of the company's nano-satellites as they orbit the earth. It covers safety-related contingencies such as the avoidance of collisions, deorbiting, re-entry and end-of-life support.

In a development that augers well for the company, the Indian Space Research Organisation's Polar Satellite Launch Vehicle completed a world record launch of 104 satellites from their Indian space launcher vehicle earlier this week.

Sky and Space have booked a ride on the same launcher vehicle to catapult their first three miniature satellites into space from the Satish Dhawan Space Centre in Sriharikota, India.

The countdown to the milestone launch is part of Sky and Space Global's longer term plan to launch a full constellation of up to 200 nano-satellites from mid-2018.

The company is looking to provide satellite based voice, text and data services to industries such as shipping and aviation and remote regions with its nano-satellite technology, which is much smaller and cheaper, but just as effective to operate as traditional satellites.

sooraj · Post by **sooraj** » 18 Feb 2017 16:57

prasannasimha · Post by **prasannasimha** » 18 Feb 2017 19:42

http://www.isro.gov.in/sites/default/fi ... n_.mp4.mp4

kit · Post by **kit** » 18 Feb 2017 20:23

Out of curiosity sakes

.. how different is an MIRV bus from a multi payload injector adapter ???

kit · Post by **kit** » 18 Feb 2017 20:25

arun wrote:ISRO Press Release.

1.Cryogenic stage designated as C25 was tested for a flight duration of 640 seconds.

2.This Stage test marks a significant milestone as it is the last in series of engine and stage development hot tests before the first development flight of GSLV MkIII.

3.First development flight of GSLV MkIII-D1 targeted for April 2017.

Below linked press release has pictures and a video:

ISRO Successfully Tests its Cryogenic Stage (C25) for GSLV MkIII for the Flight Duration

are there test facilities to simulate space conditions for engine tests ??

prasannasimha · Post by **prasannasimha** » 18 Feb 2017 22:17

They do tests in a high altitude test facility. Not in a gravity/microgravity situation.

krishGo · Post by **krishGo** » 19 Feb 2017 01:03

kit wrote:
are there test facilities to simulate space conditions for engine tests ??

´

That is what HAT (High Altitude Test) facility is for. They allow the engine to be tested at simulated high altitudes. As we go up, the atmospheric pressure drops, so these facilities allow simulation of high altitudes by enclosing the stage / engine in a similar pressure environment. Wiki tells me that most such facilities operate with a chamber pressure of of 0.16 psia (vs the sea level pressure of around 15 psi) simulating an altitude of 100,000 feet. This is close enough to understand the functioning in space.

krishGo · Post by **krishGo** » 19 Feb 2017 01:26

kit wrote:Out of curiosity sakes .. how different is an MIRV bus from a multi payload injector adapter ???

I would say they are similar. The thing with multi payloads are, usually they are destined for similar orbits & that can be ensured by the interval between separation of different payloads. Obviously, you also have missions with multiple payloads destined for different orbits/inclinations, which are much more complex and requires restart capability in the upper stage (ISRO demonstrated such capability in PSLV in one of the recent missions). Although I am not an expert on MIRV, my understanding on them is that they are similar to case 1, where you release each reentry vehicle at different times (depending on where you want it to hit).

disha · Post by **disha** » 19 Feb 2017 01:50

This gem was caught in a chinese state op-ed on ISRO's current launch of 104 sats:

"On the whole, India's space technology still lags behind the US and China's. It has not yet formed a complete system. For instance, the engine of its rockets is not powerful enough to support large-scale space exploration."

Goal of any space exploration should be:

1. Safe, Robust and Reliable
2. Cost

Now people assume that ISRO is cheaper because it pays "less" to its rocket engineers and designers. That is not the case., it is cheaper because ISRO has modularized its rockets, engines, designs and and has built up a strong foundation and investing in it over the years. For example In this launch itself ISRO tested INS1 & INS 2 which is to test out its nano-satellite bus. Now say Bangaluru Engineering Univ., Kerala - can design a space application or test out a new payload (for eg. kalaripayatu camera) strap it down onto the nano-satellite bus, and line up for launch on one regular launch slot. Like a train timetable., just book your reservation and show up on appointed date and time [Launch on demand!]

This further lowers ISRO's cost., since it can now standardize on say PSOM-XL and do away with other strap-ons. Any spare capacity can be utilized for the nano-sats. And the small sat operators can have a reliable schedule to work off. Why will they go somewhere else when they have

1. Safe Robust and Reliable launcher
2. Cost effective

In effect., we just proved that bigger is not always better.

And interestingly with PSLV ISRO completed a successful Mars mission which other nations with "more powerful" boosters could not do.

It also does not negate the fact that ISRO requires powerful boosters. ISRO's next generation space launch vehicles will come at their own due time. Towards that GSLV-Mk3 is the stepping stone. That will be an important milestone.

Around GSLV-Mk3., one can have additional boosters attached, the CUS extended or core alone - creating what others call ULV

Bheeshma · Post by **Bheeshma** » 19 Feb 2017 02:34

When is the semi cryo engine scheduled for testing? I read 2017-18 somewhere and also wiki but couldn't find a timeline from ISRO.

ranjan.rao · Post by **ranjan.rao** » 19 Feb 2017 03:00

^^Disha excellent post, may I use it to share on fb?

krishGo · Post by **krishGo** » 19 Feb 2017 03:49

Bheeshma wrote:When is the semi cryo engine scheduled for testing? I read 2017-18 somewhere and also wiki but couldn't find a timeline from ISRO.

I remember reading somewhere that they would ready for testing by 2018 although I can find nothing on it. This the most recent official information on the SCE-200

http://pib.nic.in/newsite/PrintRelease.aspx?relid=157921

An advanced space launcher that can deliver ten-tonne and heavier communication satellites to space requires a booster stage with clustered Semicryogenic engines. After the successful qualification of the Semicryogenic engine, the development of the Semicryogenic booster stage with clustered engines is expected to be initiated.

They still have some way to go since, they had to build new test facilities in Mahendragiri to support engines of this thrust range. What was already there was rated only upto 1MN of thrust I believe. There was also reports of the engine tests being done in Russia until the new facilities in Mahendragiri becomes operational. The fabrication of the first engines for test are in progress as per last financial years annual report.

Bheeshma · Post by **Bheeshma** » 19 Feb 2017 04:45

Thanks Kris. Yes I also recall 2018 time frame. Anyway let them get GSLV-III ready in meantime. I assume ULV or GSLV-III with SCE will be launched by 2019-20 only.

disha · Post by **disha** » 19 Feb 2017 06:29

ranjan.rao wrote:^^Disha excellent post, may I use it to share on fb?

Rao'ji - you do not need my permission., so please feel free! On the contrary I am honoured.

krishGo · Post by **krishGo** » 19 Feb 2017 07:00

Bheeshma wrote:Thanks Kris. Yes I also recall 2018 time frame. Anyway let them get GSLV-III ready in meantime. I assume ULV or GSLV-III with SCE will be launched by 2019-20 only.

Well it depends. For one, we do not know what the ULV itself will exactly look like and what is exactly envisioned as part of the program. We have had reports, comments from ISRO, mentions a few times here and there but nothing concrete. If ULV (or one of its variants) its just a LVM3 with a SC200 core stage (as widely reported) than a launch in the mid 2020s would be possible. A conservative estimate would be that we would have the engine in some form by 2020 and semi cryogenic core stage by 2023 (important to mention that this will be the first time ISRO will be handling RP-1 in an actual stage).

I believe the steps being currently, to the best of my knowledge & reports in the public is:
1. Complete the fabrication & testing on SCE-200 and qualify the engine
2. Develop a stage SC200 with 200 tonnes of propellant around the SCE-200.
3. Replace the core of LVM3 which is L110 with the S200. => This is/could one of the ULVs

ISRO could take anywhere between 5-8 years to complete step 3, depending on the progress of each step.

Then there is the HLV program looked like a all new launch vehicle at least from the initial concepts provided by ISRO (need the CE-50 for upper stage & S250 boosters). If it is indeed the case, then the project has to be sanctioned formally and the launch of this HLV could go into the 2030s. This can only happen after step 2 or even step 3.

Hiten · Post by **Hiten** » 19 Feb 2017 08:35

Bheeshma wrote:When is the semi cryo engine scheduled for testing? I read 2017-18 somewhere and also wiki but couldn't find a timeline from ISRO.

ISRO Chairman had alluded to SCE test being hampered by testing infra, though the engine itself could be ready. 2016 was when he had alluded to

During the Q&A session that followed, when asked, he confirmed that development of India's Semi-Cryogenic Engine [SCE] is, "in a very advanced stage". He added that demonstration of the engine could take place, "within a matter of 1 year". There is, however, a need to build test-facilities for the engine, which is taking time, he said. It is looking to work around this issue by exploring, "alternate ways of doing the test using facilities which are existing elsewhere". Translated, ISRO would want to carry out its ground tests outside the country, quite like the way GTRE does with the Kaveri engine's flight testing in Russia, aboard its modified Il-76 test-bed.

http://www.aame.in/2015/08/first-protot ... genic.html

SwamyG · Post by **SwamyG** » 19 Feb 2017 09:45

https://swarajyamag.com/insta/indias-la ... ccessfully

INdigenous cryogenic test successful.

arun · Post by **arun** » 19 Feb 2017 10:59

Bheeshma wrote:When is the semi cryo engine scheduled for testing? I read 2017-18 somewhere and also wiki but couldn't find a timeline from ISRO.

Yes, thereabouts.

The latest information regards time line I have come across on the Semicryogenic SCE-200 / SC 160 stage dates back to a September 2016 article by Hindu quoting Dr. K. Sivan, Director VSSC.

Per that a GSLV Mk III aka LVM3 with the SCE-200 / SC 160 should launch end 2018. I presume this means that SCE-200 / SC 160 would replace the L110 stage.

Pre-project work on what is called the SCE-200 began about four years back. "We plan to have an [semi-cryogenic] engine and stage capable of flight by the end of 2018 and try it on the GSLV-MkIII.

This would readily boost Mk-III's maximum lifting capability from 4,000 kg to 6,000 kg,” Dr K. Sivan, Director of Vikram Sarabhai Space Centre at Thiruvanthapuram, the lead centre for launch vehicle development, said.

From The Hindu here:

Clicky