Indian space startup "EtherealX" is building a fully re-usable medium lift rocket. They are getting funded from Indo-US technology fund (INDUS-X):
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The Stallion engine shown above will be a "closed gas generator cycle". I am not sure what that means. Gas generator cycles by their very nature are open cycles. As in fuel & oxidizer is used to turn the main turbopump & feed the combustion chamber. The propellant used in running the turbopump is dumped overboard. Since we are losing this propellant, it is called an open cycle. A closed gas generator cycle is called an expander cycle. Why not just call it that? We will have to wait for more updates on this.
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Anyway, the Stallion is their lower stage engine. Thus, it is more powerful & more challenging. They are starting off their engine development with the smaller upper stage engine called "Pegasus".
They have 3D printed a prototype of the Thrust Chamber Assembly (TCA) of the "Pegasus" upper stage semi-cryogenic engine:
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The spaces of the engine are as follows:
Propellant: RP-1/LOX
Thrust: 40 kN (sea level)
Isp: 293 sec (sea level)
Cooling: Regenerative
The engine feed cycle is rather interesting. The company describes it as "A proprietary, all-new, indigenously developed rocket engine feed cycle: the Full Flow Segregated Cooling Cycle (FSCC)". But also says this TCA is the "The world’s first RP-1/LOX engine TCA that can also run on an expander cycle".
It seems to me that this FSCC is a modified variant of the dual expander cycle. If it is genuinely an all-new engine cycle, this would be the 1st by any Indian organization/company. We will have to wait & see on that front.
They are getting ready to test the Pegasus TCA:
Video if the Pegasus TCA test rig:
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It going to be very very tough, but I hope they can make this work. Can you imagine having reusable rocket with payload similar to the LVM3. It will be a game changer for our military & civilian needs.
Can EtherealX Become India’s SpaceX with Its Fully Reusable Rocket?
09 Jun'25 | By Tapanjana Rudra
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SUMMARY
- Spacetech startup EtherealX claims to have learned from the failures of SpaceX's Falcon launch and built its own technology to make medium-lift rockets fully reusable
- EtherealX has built its own re-entry algorithm, which is being tried out not only in its own test vehicles but also in test launches
- EtherealX has a $130Mn order book in place from satellite operators in the US, Japan, and some European countries
Late-winter frost was in full spell when a sleepy Polish town woke up to mysterious fireballs lighting up the obsidian sky on a February night.
Neither Helios was on an errand, nor a mythical dragon was on a recce of the Polish skies that night. Experts confirmed the next day that those were the wrecks of the upper stage of Falcon 9’s reusable launch vehicle that had failed to deorbit on time, malfunctioned, broke into pieces, and crashed down on earth like fireballs.
Elon Musk’s SpaceX grounded Falcon 9 rockets multiple times last year following anomalies in the recovery of their second stage or upper stage. From a liquid oxygen leak to a malfunction while grounding, the company has faced multiple failures while bringing the upper stage of its reusable rockets back to Earth.
"As California-headquartered SpaceX tries to comprehend the rocket science behind the failures, Bengaluru-based spacetech startup EtherealX claims to have learned from the Falcon fallacies. Lessons that the startup is using to build medium-lift fully reusable launch vehicles or rockets."
While deep-pocket giants like SpaceX, Blue Origin, and Rocket Lab have cracked the code of recovering the first stage or the booster stage of their medium-lift launch vehicles, but failed to make their satellite launch vehicles (SLVs) fully reusable for various tech constraints, EtherealX claims to be a pioneer in the Indian spacetech system to make rockets that can be reused fully.
EtherealX says it has built advanced hardware and software stacks, and worked around with the existing laws of physics to build its flagship Razor Crest Mk-1 that can be brought back to the launch pad after it docked a satellite into Low Earth Orbit (LEO), Geostationary Transfer Orbit (GTO), or following a trans-lunar injection (TLI).
With an eye on global markets, EtherealX plans its first commercial launch in 2027 to capture a major share of the Indian spacetech market that’s set to surpass $44 Bn by 2030.
The Making of EtherealX: From Vedas to Falcon Fallacies
As a child, Manu Nair was deeply inspired by the Vedas and was intrigued by celestial matters. He wanted to grow up to explore the mysteries of the cosmos. After his graduation in engineering from the BML Munjal University, he interned at the Human Space Flight Centre of the Indian Space Research Organisation (ISRO) in late 2019. He met Shubhayu Sardar there.
Before the ISRO assignment, Nair had the opportunity to work closely with commercial space flight planning as a part of NASA-supported Project PoSSUM (Polar Suborbital Science in the Upper Mesosphere). By late 2020, he joined Indian spacetech startup Manastu Space’s executive team and met Prashanth Sharma, who was heading propulsions in the company.
Nair introduced Sharma to Sardar at a dinner a year later. That’s where the entire game changed for the trio. Sharma turned down an offer from the US-based Rocket Lab, Sardar quit ISRO, and Nair called off his plans to join an American company.
The three space enthusiasts teamed up and the seed of EtherealX germinated in 2022.
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“That night at the dinner, the fundamental question we asked was why we still did not have resilient or multi-polar launch infrastructure. Even as launch costs had come down over the last few decades, mathematically, there should have been an oversupply of launch vehicles, but that was not the case. Launch was not a solved problem at all. It was an extremely polarised market where over 80% of all launches were being done by one vehicle, one company, and one demography,” Nair, the CEO of the spacetech startup, shared with Inc42.
They realised that most companies were not operating in the right segment of launch vehicles or did not follow the right approach, which was causing trouble for the satellite operators who had to wait long for launches. The idea was also to solve for unit economics.
"The answer was reusability. That was the core idea of the spacetech startup."
It wasn’t anything novel. The first reusable rocket, the Space Shuttle, was developed by NASA. Since 1981, the Space Shuttle fleet undertook 135 missions, inspiring generations of scientists.
The Space Shuttle comprised an external tank, two solid rocket boosters on the sides, and an orbiter. Only the external tank could not be recovered after launch. The solid rocket boosters landed in the ocean that NASA retrieved, inspected, refurbished, and reused, while the orbiter returned to Earth and landed like an airplane after completing its space mission.
"SpaceX created history in 2015 when it became the world’s first to bring back its Falcon 9 rocket in a soft touchdown during an orbital launch. “SpaceX too has had multiple failures. The company goes public stating the cause of the failure, but never discloses how they fixed it. We spotted the errors and framed our strategy based on what not to do. At EtherealX, we started off with the mitigation strategies for the issues SpaceX was facing,” Nair said."
It was almost impossible to replicate the SpaceX model, given that the company has a vertically integrated business. The EtherealX founders started building proprietary technology from the ground up that could recover both the booster stage and upper stage of the rockets – going one step ahead of what SpaceX has achieved so far, according to the CEO.
EtherealX has so far carried out a few private tests of its launch vehicle engine, while its fully reusable launch vehicle is still under testing and designing. It has recently signed an agreement with In-Space for facilitating the testing of its engines with ISRO. Its first hot fire will be done at its own facility in November, when the engine will be fired up and operated in a controlled environment for its performance and safety checks.
The company raised $5 Mn in a seed round last year from YourNest VC, BIG Global Investments, BlueHill Capital, and Golden Sparrow Ventures, to proceed with the final tests and qualification of the vehicle engine.
The Tech Edge: Spotting SpaceX Gaps
A two-stage-to-orbit (TSTO) launch vehicle has two main parts – the first or the booster stage and the upper or the second stage. Whether it’s SpaceX’s Falcon 9 or Blue Origin’s New Glenn or EtherealX’s Razon Crest – all medium-lift rockets have the same architecture.
After a rocket blasts off, there is the main engine cut off (MECO) stage, which SpaceX typically performs at an altitude of 80 km above the ground. It provides the initial acceleration and lift for the rocket. After MECO, the upper stage engine does the firing, and with enough velocity already built in it, the stage reaches the desired orbit for a satellite launch.
"Nair explained that the hardware capabilities can be reimagined in building these stages to achieve complete reusability. Technical challenges, however, stay on in bringing back the booster – a problem that lies in realigning the algorithm in flight software."
EtherealX has built its own re-entry algorithm, which is being tried out not only in its own test vehicles but also in test launches. “During every launch done by SpaceX, because it’s public information, we run our algorithm during relanding and predict before the launch when the booster is going to turn over, when it’s going to come back, when the boost back burn is going to happen,” Nair said.
He claimed that in the fourth run of its algorithm, its predictions reached a 100% perfection. The startup is collecting more data and polishing its existing algorithm each day.
Most vehicles face hardware issues due to the engine heat while re-entering the Earth’s atmosphere, often causing damage to the rockets. EtherealX has built a rocket engine feed cycle that would use the heat generated by the vehicles during their re-entry to the Earth’s atmosphere as the source to again run the engines.
The company will use a ‘source-sink mechanism’ to channel the re-entry heat for re-use. Nair did not elaborate on the mechanism further because the technology is proprietary and awaits patent approval.
"Most companies are still struggling with the technology that can recover the upper stage. EtherealX claims that it has solved that problem with a ballistic plus skip atmospheric re-entry. “For the upper stage to come back, it will be a free fall with some controlled direction till a certain altitude, and then we will power the engines to perform a cross range manoeuvre for the last bit,” Nair said, without explaining it further."
He, however, accepted that this was only in theory so far. While EtherealX is confident of the safe recovery of its booster stage, the credibility of its biggest value proposition, the upper stage recovery, remains dicey until a few flights are successful.
This USP is also directly linked to its business model, and hence, revenue and profitability. In case of a failure to recover the upper stage its margins will be hit. “But it won’t stop us from making money, and we’re confident that even if by the third or fourth launch we can achieve a full recovery level, it’s going to be a win-win for us and the end user.”
Razon Crest can carry 24.8 tonnes of payload in the non-reusable configuration. As a fully reusable vehicle, it can carry 8 tonnes in LEO and 1.6 tonnes in GTO. In a partially reusable configuration, the rocket can carry 22.8 tonnes in LEO, 8.3 tonnes in GTO, and 4.2 tonnes during trans-lunar injection.
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Mapping The Skies: From Stargazing To A $130 Mn Order Book
EtherealX has a $130 Mn order book in place from satellite operators in the US, Japan, and some European countries.
"The startup plans to charge anywhere between $350 and $2,000 per kg, based on various configurations. If things pan out as planned, it is expected to see revenue coming in by early 2027 ahead of the planned launches."
From here on, the company is taking steady steps to reach its commercial launch target on time. To ensure the tests are done as planned, EtherealX is working towards the completion of its 16-acre test facility in Tamil Nadu within a few months. It is also aiming to carry out an upper stage cycle testing next year.
As the sky gets crowded with an increasing number of spacetech ventures vying for a slice of the $466.1 Bn global market, EtherealX is trying to stand out from US startup Stoke Space, which is also working on building fully reusable launch vehicles, or homegrown Agnikul, working in this broader domain of launch vehicles for small to medium satellite launches, with its technology edge that allows a much higher payload.
Dreaming it big – taking on giants like SpaceX and Blue Origin – EtherealX has reached a crucial point where its ability to raise more capital and succeed in on-ground tests will decide both the fate of the company as well as that of the country’s burgeoning spacetech ecosystem.
[Edited By Kumar Chatterjee]
Can EtherealX Become India’s SpaceX With Its Fully Reusable Rocket?
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