Some background info:
Since the end of the LVM3's R&D work ISRO had wanted a more powerful rocket. VSSC had showcased many concepts of heavy lift rockets to GoI with the hopes of securing funding. Initial concepts from 2015-16 were heavily reliant on proven propulsion technologies like solid rockets & hypergolic fueled engines. Essentially, they wanted to make a larger LVM3:
These concepts got no traction with the GoI. So, they went back to the drawing board. Around this time the CE-20 engine was flown & ISRO was making steady progress with the SCE-200 engine. VSSC assumed both the CE-20 & the SCE-200 engines would become operational pretty quickly. So, they designed a new Heavy Lift Vehicle (HLV) that incorporated these new propulsion technologies. That's how we got with this:
VSSC continued to refine the HLV configuration. In the following years we saw many versions of this HLV:
Recent push for a new rocket:
Around 2017-18, the PM started pushing for the Gaganyaan mission. While the Gaganyaan mission can be performed by the LVM3, a more sustained human spaceflight mission with space stations & all would require a more powerful rocket. This rocket was tentatively named Next Generation Launch Vehicle (NGLV) & the Project was named "Soorya".
Thus, the HLV project went from a concept study to a project that the GoI was looking to fund. By late 2019 it was becoming clear to ISRO that the issues with the SCE-200 engine were bigger than previously anticipated. It's not likely that the engine would become operational before 2025. Therefore, basing a future LV on this engine would greatly delay that project too. The SCE-200 is a Kerolox engine & would thus build up a lot of soot. Refurbishing & reusing such an engine is very expensive. So, a re-usable stage with this engine wasn't possible.
Technology development:
1. Engines:
Globally there is a clear shift towards Methalox engines for next gen launchers. In the US you had SpaceX & Blue Origin, in Europe they have the Prometheus engine & the Ariane Next launcher. ISRO tested the gas generator of the CE-20 engine with Methalox propellant & found it compatible.
LPSC quickly modified the powerhead of the CE-20 engine to accept Methalox propellant.
This was used as a technology demonstrator engine & also as a steppingstone to build a more powerful engine.
ISRO proposed building 2 Methalox engines. One would be 100 ton thrust range for lower stages & another for upper stages.
The engines are going to be a gas generator cycle type. Since GGs are easier to make & ISRO has a lot of experience with this cycle. Recently LPSC put out a tender for laser powder bed fusion 3D printing of a subscale thrust chamber of the future 100 ton thrust methalox engine.
This engine will progress quickly. The design is a scaled-up eversion of the CE-20 & all testing facilities are available in house.
Specs of the 100-ton engine:
continued below...
Since the end of the LVM3's R&D work ISRO had wanted a more powerful rocket. VSSC had showcased many concepts of heavy lift rockets to GoI with the hopes of securing funding. Initial concepts from 2015-16 were heavily reliant on proven propulsion technologies like solid rockets & hypergolic fueled engines. Essentially, they wanted to make a larger LVM3:
These concepts got no traction with the GoI. So, they went back to the drawing board. Around this time the CE-20 engine was flown & ISRO was making steady progress with the SCE-200 engine. VSSC assumed both the CE-20 & the SCE-200 engines would become operational pretty quickly. So, they designed a new Heavy Lift Vehicle (HLV) that incorporated these new propulsion technologies. That's how we got with this:
VSSC continued to refine the HLV configuration. In the following years we saw many versions of this HLV:
Recent push for a new rocket:
Around 2017-18, the PM started pushing for the Gaganyaan mission. While the Gaganyaan mission can be performed by the LVM3, a more sustained human spaceflight mission with space stations & all would require a more powerful rocket. This rocket was tentatively named Next Generation Launch Vehicle (NGLV) & the Project was named "Soorya".
Thus, the HLV project went from a concept study to a project that the GoI was looking to fund. By late 2019 it was becoming clear to ISRO that the issues with the SCE-200 engine were bigger than previously anticipated. It's not likely that the engine would become operational before 2025. Therefore, basing a future LV on this engine would greatly delay that project too. The SCE-200 is a Kerolox engine & would thus build up a lot of soot. Refurbishing & reusing such an engine is very expensive. So, a re-usable stage with this engine wasn't possible.
Technology development:
1. Engines:
Globally there is a clear shift towards Methalox engines for next gen launchers. In the US you had SpaceX & Blue Origin, in Europe they have the Prometheus engine & the Ariane Next launcher. ISRO tested the gas generator of the CE-20 engine with Methalox propellant & found it compatible.
LPSC quickly modified the powerhead of the CE-20 engine to accept Methalox propellant.
This was used as a technology demonstrator engine & also as a steppingstone to build a more powerful engine.
ISRO proposed building 2 Methalox engines. One would be 100 ton thrust range for lower stages & another for upper stages.
The engines are going to be a gas generator cycle type. Since GGs are easier to make & ISRO has a lot of experience with this cycle. Recently LPSC put out a tender for laser powder bed fusion 3D printing of a subscale thrust chamber of the future 100 ton thrust methalox engine.
This engine will progress quickly. The design is a scaled-up eversion of the CE-20 & all testing facilities are available in house.
Specs of the 100-ton engine:
continued below...
