ISRO Project Surya: Next Generation Launch Vehicle (NGLV)

[Pundit Pikachu]

Wait a minute ! Who said we have to use methlox in upper stage ? Because I surely didn't !

My only question is why we don't build a 2 stage LV with reusable 1st stage. THAT'S IT

New glenn - 13.6 t to GTO

And BTW a 4-6t to GTO & 10-16t to LEO would suffice our 99% of needs

For God's sake mate, just read check all the five pages of the thread before doing whatever you are doing here.

Post in thread 'ISRO Project Surya: Next Generation Launch Vehicle (NGLV)'

Oct 7, 2024

Intresting thread by Indranil Roy on Why NGLV uses a cluster of 9 engines and went for a 3 stage design instead of the more conventional 2 stage approach


View: https://x.com/Indrani1_Roy/status/1752059713641120186

Thread by @Indrani1_Roy on Thread Reader App

@Indrani1_Roy: For me, NGLV is the most exciting developments from ISRO. Enough info has trickled out to make some educational guesses. Thank you @TitaniumSV5 for capturing the slide Dr. V. Narayanan, Director, LPSC...…

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• Pundit Pikachu

• 

View: https://m.youtube.com/watch?v=3zFzsnUQe-k

ISRO chief himself explained the reason for a 3 stage LV instead of a 2 stage one in this video at 34:24

 

[pipebomb]

Appreciate your reply

For God's sake mate, just read check all the five pages of the thread before doing whatever you are doing here

My question was in general and not in particularly for NGVL. I didn't know where to ask it and decided that this thread would be close enough

ISRO chief himself explained the reason for a 3 stage LV instead of a 2 stage one in this video at 34:24

Indranil didn't actually answer the question of why 3 stage are required unlike Somnath ji who did.

Somnath ji basically said that a 2 stage LV's spent stage would impact land mass of SE nations and also something about having to build a bigger upper stage something something

Now I am a bit confused because distance between Sriharikota and Thailand or Malaysia is approximately 2000km which is huge. For example a much bigger rocket than NGLV like new glenn with a 13.5t gto capacity only makes a 620 miles (1000km) down range landing on a barge in sea. Our requirement LV is much lower around 4-6t to gto. So our should be way less

Please keep in mind that reusable 1st stage landing involves deacceleration in both fly back and in sea landing

 

[Anonymous Bharata]

Wait a minute ! Who said we have to use methlox in upper stage ? Because I surely didn't !

My only question is why we don't build a 2 stage LV with reusable 1st stage. THAT'S IT

New glenn - 13.6 t to GTO

And BTW a 4-6t to GTO & 10-16t to LEO would suffice our 99% of needs

For 5T to GTO in Reusable mode, you need 10T to GTO in Expendable mode

So, inorder to achieve that requirement, using the LME-1100 ( a gas generator cycle engine, vac Isp of 335sec) you need to achieve very low structural factors, those numbers are very difficult to achieve even with advanced materials like Al-Li Alloy and precision manufacturing....it's simply impossible, hence ISRO choose 3 stage to Orbit....

As far as New Glenn is concerned, their engine is Oxidiser Rich Staged Combustion, hence it has higher Isp than our LME-1100 engine, hence they can achieve TSTO with higher structural factors

If you have lower ISp engine, then your rocket should have Lower Structural Factors to achieve same payload as that of Rocket with Higher Isp & Higher Structural Factors, hope you understand now

 

[pipebomb]

For 5T to GTO in Reusable mode, you need 10T to GTO in Expendable mode

So, inorder to achieve that requirement, using the LME-1100 ( a gas generator cycle engine, vac Isp of 335sec) you need to achieve very low structural factors, those numbers are very difficult to achieve even with advanced materials like Al-Li Alloy and precision manufacturing....it's simply impossible, hence ISRO choose 3 stage to Orbit....

As far as New Glenn is concerned, their engine is Oxidiser Rich Staged Combustion, hence it has higher Isp than our LME-1100 engine, hence they can achieve TSTO with higher structural factors

If you have lower ISp engine, then your rocket should have Lower Structural Factors to achieve same payload as that of Rocket with Higher Isp & Higher Structural Factors, hope you understand now

So you're saying using 3 stage has everything to do with ISP and little to nothing to do with spent stages. Correct me if I got that wrong

 

[ArjunMK1A]

The problem is simple.

1. Lost GISAT 1, EOS3 and EOS9 which is intended for Military purpose.
2. Indian Navigation Satellite project is in dire situation. 7 Failed rockets with 4 Operating. Serious problem with Navigation system required for Precision strikes.
3. Now upcoming SBS is 54 Satellite and we are planning to do it short period.

Now, loosing Satellite is part and parcel of the game. But if we replenish sooner than no issue. But we take years to do the replenishment. Top of that ISRO cannot do more than 6 launches per year.

It is better to start building Launchers in large scale since we have lot of Satellites to launch. 54 SBS with replacement for GSAT, EOS3, 9. Followed by further expansion of NVS series satellite. Current capability is 1500KM from Indian Border. We should start world wide service, since we can provide service to poor countries.


Also if we are allowing Private consortium to build PSLV. It is better to let them build GSLV MK2 and LVM3 for Commercial Satellite launching. At least they can prepare the OEM who can work with them when NGLV come into picture.

GOI chumps should open the purse.