GEO Imaging Satellite (GISAT)

[pipebomb]

I would like to know why all major space powers shifted or trying to shift to expander cycle engine for their upper hydrolox stage. Except isro, even blue origins is also developing a hydrolox expander cycle engine

 

[RoaringTigerHiddenDragon]

And finally, ISRO spends way too less. Even the Russians spend 3 times that of ISRO. I am pretty sure the government knows it is underspending in space. But I think they are reluctant to up the budget because they don’t believe in ISRO yet. Instead, they resorted to a pay cut causing scientists to leave ISRO. And have instituted the InSpace program to “help” ISRO.

https://static.toiimg.com/photo/imgsize-88009,msid-73808482/73808482.jpg

China spent 7 times more than India on space; US 13 times | India News - Times of India

India News: The Chinese government — whose push for the space programme has seen the Chinese space agency race ahead in the past few years — has spent seven times

timesofindia.indiatimes.com

 

[RoaringTigerHiddenDragon]

Some more information on the launch failure:

Indian rocket failure blamed on upper stage malfunction – Spaceflight Now

 

[RoaringTigerHiddenDragon]

SpaceX falcon9 versus ISRO GSLV Mk3..ISRO is way behind the Falcon9. Even the launch cost of a Falcon9 ($50 million) is less than the GSLV Mk3 ($63 million). How will ISRO compete at all? Impossible.

How does ISRO’s GSLV Mk-III fare against some of the world's most powerful rockets?

ISRO operates one of the most reliable and cost-effective launch platforms in the world.

www.firstpost.com

 

[RoaringTigerHiddenDragon]

I would like to know why all major space powers shifted or trying to shift to expander cycle engine for their upper hydrolox stage. Except isro, even blue origins is also developing a hydrolox expander cycle engine

Here’s a comparison of various cryogenic engines:

Cryogenic rocket engine - Wikipedia

en.wikipedia.org

Looks like CE7.5 type engines which replaced soviet union’s kvd1 have been retired everywhere. Looks like ‘staged combustion’ is an outdated technology other agencies don’t use anymore.

 

[Vamsi]

Here’s a comparison of various cryogenic engines:

Cryogenic rocket engine - Wikipedia

en.wikipedia.org

Looks like CE7.5 type engines which replaced soviet union’s kvd1 have been retired everywhere. Looks like ‘staged combustion’ is an outdated technology other agencies don’t use anymore.

staged combustion cycle is not outdated tech. It is the most efficient thermodynamic cycle when compared to others cycles. The problem is that it is also more complex when compared to other cycles

 

[Vamsi]

Instead of wasting money on useless schemes for filthy people this is where government should spend.

we are spending more than 1.5 lac crores and 2.5 lac crores on minority and SC/ST schemes, while ISRO and DRDO budgets are less than 15K crores each

 

[Vamsi]

I would like to know why all major space powers shifted or trying to shift to expander cycle engine for their upper hydrolox stage. Except isro, even blue origins is also developing a hydrolox expander cycle engine

Expander cycle is simple and cheap , but it is least efficient of all the cycles. What's the point of developing a new upper stage Cryo engine when we already have the most powerful one

 

[RoaringTigerHiddenDragon]

staged combustion cycle is not outdated tech. It is the most efficient thermodynamic cycle when compared to others cycles. The problem is that it is also more complex when compared to other cycles

Never ever use complex technology if simpler ones are available. This is perhaps why other agencies don’t use staged combustion cycle. Russia does not use KVD 1 (from which CE7.5 is derived) anymore. Plus CE7.5 is NOT the latest tech. That would be Full flow staged combustion that SpaceX’s Raptor deployed in 2019. CE7.5 is a fuel rich staged combustion and looks like no other agency uses this technology anymore. Perhaps the failure rate is high due to complexity and hence have not gone that route.
Oxidizer rich staged combustion is the most popular. The technology ISRO uses was developed in the 1970s and not used anymore and even to begin with only 3 or 4 engines used it compared to more than two dozen engines using oxidizer rich staged combustion cycle. Looks like ISRO may have gone for a complex technology because only Russia was ready to tech transfer cryogenic technology I.e. KVD1 fuel rich SC cycle. So ISRO may not have had any choice. But they could have tried to develop the safer oxidizer rich SC or full flow SC tech all these years. Why didn’t they?

Staged combustion cycle - Wikipedia

en.wikipedia.org

Here’s some literature on the various cycles:

https://ocw.mit.edu/courses/aeronautics-and-astronautics/16-512-rocket-propulsion-fall-2005/lecture-notes/lecture_25.pdf

Apparently the space shuttle used the staged combustion cycle.

 

[RoaringTigerHiddenDragon]

Looks like the reason ISRO might have postponed the HSP is because of low budgets. ISRO said they need $1.5 billion for HSP. Government gave them $180 million. Lol.

India faces big budget cut for new human spaceflight program

India's space agency wants to launch its own astronauts by August 2022, but this year's budget for the program may be one-third of what officials had hoped for.

www.space.com

 

[RoaringTigerHiddenDragon]

Very detailed article on how ISRO churns out low cost missions. A good read.

Chandrayaan-2: How ISRO churns out low-cost missions

ISRO has advantage over NASA in terms of manpower and infrastructure-running costs

www.theweek.in

 

[Vamsi]

Never ever use complex technology if simpler ones are available. This is perhaps why other agencies don’t use staged combustion cycle. Russia does not use KVD 1 (from which CE7.5 is derived) anymore. Plus CE7.5 is NOT the latest tech. That would be Full flow staged combustion that SpaceX’s Raptor deployed in 2019. CE7.5 is a fuel rich staged combustion and looks like no other agency uses this technology anymore. Perhaps the failure rate is high due to complexity and hence have not gone that route.
Oxidizer rich staged combustion is the most popular. The technology ISRO uses was developed in the 1970s and not used anymore and even to begin with only 3 or 4 engines used it compared to more than two dozen engines using oxidizer rich staged combustion cycle. Looks like ISRO may have gone for a complex technology because only Russia was ready to tech transfer cryogenic technology I.e. KVD1 fuel rich SC cycle. So ISRO may not have had any choice. But they could have tried to develop the safer oxidizer rich SC or full flow SC tech all these years. Why didn’t they?

Staged combustion cycle - Wikipedia

en.wikipedia.org

Here’s some literature on the various cycles:

https://ocw.mit.edu/courses/aeronautics-and-astronautics/16-512-rocket-propulsion-fall-2005/lecture-notes/lecture_25.pdf

Apparently the space shuttle used the staged combustion cycle.

Who said to you that Oxidizer Rich Staged Combustion Cycle is safe.No, It's not safe. Infact Oxidizer Rich Staged Combustion is far more complex than a fuel rich cycle , because in Oxidizer Rich cycle, the Oxygen rich mixture corrodes the metal with which it interacts. It's very difficult to master , that's the reason why Americans had failed to master the Oxidizer Rich cycle untill they bought the NK-33 engines after the end of cold war. Only the Russians were masters in Oxidizer Rich cycles. Hence our SCE-200 engine is based on RD-810 design which inturn derived from RD-170

 

[gslv markIII]

Here’s a comparison of various cryogenic engines:

Cryogenic rocket engine - Wikipedia

en.wikipedia.org

Looks like CE7.5 type engines which replaced soviet union’s kvd1 have been retired everywhere. Looks like ‘staged combustion’ is an outdated technology other agencies don’t use anymore.

Oh my my... Please check the specific impulse of staged combustion with gas generator & expander cycles.

 

[gslv markIII]

Expander cycle is simple and cheap , but it is least efficient of all the cycles. What's the point of developing a new upper stage Cryo engine when we already have the most powerful one

Least efficient in terms of specific impulse is the gas generator cycle. Expander cycle is comparable to staged combustion cycle.

Also it's a trade- off. That extra plumbing for expander cycle would add weight which may as well nullify any payload capacity you gain by using it.

 

[RoaringTigerHiddenDragon]

Who said to you that Oxidizer Rich Staged Combustion Cycle is safe.No, It's not safe. Infact Oxidizer Rich Staged Combustion is far more complex than a fuel rich cycle , because in Oxidizer Rich cycle, the Oxygen rich mixture corrodes the metal with which it interacts. It's very difficult to master , that's the reason why Americans had failed to master the Oxidizer Rich cycle untill they bought the NK-33 engines after the end of cold war. Only the Russians were masters in Oxidizer Rich cycles. Hence our SCE-200 engine is based on RD-810 design which inturn derived from RD-170

What? Did you see the link I put in there? Most engines use Oxidizer rich combustion cycle. Even blue origin for passenger travel to space. They are not going to use unsafe tech for human flights? The tech that ISRO uses, no one uses the fuel rich cycle. Why is that?

 

[gslv markIII]

SpaceX falcon9 versus ISRO GSLV Mk3..ISRO is way behind the Falcon9. Even the launch cost of a Falcon9 ($50 million) is less than the GSLV Mk3 ($63 million). How will ISRO compete at all? Impossible.

How does ISRO’s GSLV Mk-III fare against some of the world's most powerful rockets?

ISRO operates one of the most reliable and cost-effective launch platforms in the world.

www.firstpost.com

The cost is a little more than 300 crore, it will match up to the reused Falcon 9 with introduction of uprated cryogenic stage & SC120.

 

[RoaringTigerHiddenDragon]

Oh my my... Please check the specific impulse of staged combustion with gas generator & expander cycles.

We are talking within SC cycles - there are 3 types of SC cycles. See link I supplied. We will go by what is popular with space agencies. I am sure those guys know what is best. And clearly the CE7.5 technology is the least used or unpopular. And the full cycle SC appears to be the latest and most complex. Read the literature at a high level.

 

[RoaringTigerHiddenDragon]

The cost is a little more than 300 crore, it will match up to the reused Falcon 9 with introduction of uprated cryogenic stage & SC120.

View attachment 104665

Yeah that’s what the article says. Plus Falcon9 has been launched 52 times compared to two times for Mk3. You can kiss heavier launch market goodbye as SpaceX is going to corner 70-80% market share. Technology can also bring down costs. I think ISRO’s marketing of cheaper launch costs due to low manpower costs won’t last forever. Better figure out what needs to be done to compete against Falcon9, urgently.

 

[gslv markIII]

We are talking within SC cycles - there are 3 types of SC cycles. See link I supplied. We will go by what is popular with space agencies. I am sure those guys know what is best. And clearly the CE7.5 technology is the least used or unpopular. And the full cycle SC appears to be the latest and most complex. Read the literature at a high level.

I know there are three types.

The reason for ISRO choosing staged combustion cycle in the first place for the GSLV CUS instead of simpler GG cycle is because it was supposed to be replacement of the KVD 1 stage in form, fit and function.

FFSC is complex & is used in metholox engines. ORSC in kerolox engines as fuel have coking (soot deposition) issues.

Hydrogen do not have that problem. Hence FRSC for cryogenic engines.

 

[RoaringTigerHiddenDragon]

I know there are three types.

The reason for ISRO choosing staged combustion cycle in the first place for the GSLV CUS instead of simpler GG cycle is because it was supposed to be replacement of the KVD 1 stage in form, fit and function.

FFSC is complex & is used in metholox engines. ORSC in kerolox engines as fuel have coking (soot deposition) issues.

Hydrogen do not have that problem. Hence FRSC for cryogenic engines.

Yeah that’s what I am saying - we are stuck with an unpopular Russian technology. So now what? Can we develop an oxidizer SC tech or the latest full cycle tech?
Can we bring the Mk3 launch costs 30% cheaper than Falcon9?

Why is ISRO not openly discussing any of this, btw?