Indian Space Program: News & Discussion

[a_bharat]

AgniKul Cosmos
@AgnikulCosmos
Humbled to share that we successfully test fired 3 semi-cryogenic rocket engines simultaneously, as a cluster. All the 3 engines are 3d printed as single pieces of hardware - designed and manufactured in-house at AgniKul Cosmos Rocket Factory - 1. As with all our propulsion systems, these 3 engines are also powered by electric motor driven pumps.

This test involved calibrating 6 pumps, 6 motors and tuning 6 speed control algorithms to work together in perfect sync to achieve uniform startup, steady state and shutdown performance across the entire system.

To the best of our knowledge, this is the first time such a test has been performed in India with semi cryogenic engines. We are extremely grateful to have the opportunity to be building world class, original space technology from India, for the world with the support of
@isro and @INSPACeIND

[uddu]

Dhawan-III | Static Test Fire | Skyroot Aerospace
National Science Day marks the discovery of the Raman Effect, encouraging young people across the country to continue pursuing their passions in STEM. Today feels like the right moment to share what we've been building to fuel further innovation at Skyroot.

Dhawan-III, our upgraded cryogenic rocket engine, just completed a 145-second endurance test on an indigenous mobile test stand built in-house.

This engine has been developed under the Aatmanirbhar Bharat ARISE-ANIC initiative with a focus on reusability and greener propulsion.

Happy National Science Day.

[sanjaykumar]

What do those shock diamond thingees signify?

[drnayar]

What do those shock diamond thingees signify?

Rocket engine exhaust often contains a distinctive pattern known as shock diamonds or Mach diamonds. These are a series of shock waves and expansion fans that increase and decrease, respectively, the supersonic exhaust gases’ pressure until it equalizes with atmospheric pressure. The bright glowing spots visible to the naked eye are caused by excess fuel in the exhaust igniting. As awesome as shock diamonds look, they’re actually an indication of inefficiencies in the rocket: first, because the exhaust is over- or underexpanded, and second, because combustion inside the engine is incomplete. Both factors reduce a rocket engine’s efficiency (and both are, to some extent, inescapable).

https://fyfluiddynamics.com/2015/10/roc ... stinctive/

[sanjaykumar]

Thanks. Often wondered.

[drnayar]

and they have use in assessing calibration of rocket engines and assessing performance

Pressure Matching: They appear when the exhaust pressure doesn't match the surrounding air. If an engine is designed for high altitude, it will show these diamonds at sea level because it is over-expanded.

Flow Verification: Engineers use high-speed schlieren photography to see these waves, confirming the exhaust is supersonic.

Performance Tuning: The angle and length of the diamonds allow engineers to calculate the exhaust Mach number and pressure ratios.

Combustion Efficiency: If diamonds are visible to the naked eye, it often means unburned fuel is reigniting in the shock waves, signaling incomplete combustion.

how they form :

Imbalance: Exhaust leaves the nozzle at a different pressure than the atmosphere.
Compression: The outside air "squeezes" the exhaust, creating a shock wave.
Expansion: The gas bounces back, expanding past the ideal point.
Repetition: This "bouncing" repeats, forming the diamond chain until the pressures eventually equalize

How nozzle shapes affect shaping [ or not]

Nozzle shape fundamentally changes how exhaust interacts with the atmosphere, which determines if and how shock diamonds appear. While traditional bells create fixed patterns, advanced shapes like aerospikes are designed to "self-correct" and minimize them.

1. Traditional Bell Nozzles (Static Patterns)
Bell nozzles are optimized for a single altitude. At any other altitude, the pressure mismatch creates visible shock diamonds.
Over-expanded (Low Altitude): The nozzle is "too big" for the high air pressure at sea level. The air "pinches" the exhaust inward as it leaves the nozzle, creating a series of inward-pointing shock waves that form the first diamond.
Under-expanded (High Altitude): The exhaust leaves at a higher pressure than the thin air and "billows" outward. It then snaps back inward due to expansion fans, creating diamonds that appear larger and further downstream.

2. Aerospike Nozzles (Minimal/Dynamic Patterns)
An aerospike engine is essentially a bell nozzle turned inside out.

Altitude Compensation: Instead of a fixed metal wall, it uses the ambient air pressure as one "wall" of the nozzle.
Diamond Suppression: Because the exhaust is always exposed to the atmosphere, it constantly adjusts its expansion to match the outside pressure. This means the exhaust is almost always "perfectly expanded," which theoretically eliminates or significantly reduces the pressure imbalances that cause shock diamonds.
Visual Difference: If diamonds do appear in an aerospike (such as in linear variants), they are often less distinct or only visible when viewed from specific angles (e.g., from the end of a linear spike).

3. Dual-Bell and E/D Nozzles
These are "hybrid" shapes designed to have two optimal points.

Dual-Bell: These have a "kink" in the nozzle wall. At low altitudes, the flow separates at this kink, creating a smaller effective nozzle and smaller, sharper shock diamonds. As the rocket climbs, the flow "attaches" to the full bell, and the diamonds shift to a larger pattern.

Expansion-Deflection (E/D): Uses a center pintle to push exhaust outward. This creates a hollow exhaust plume where shock diamonds might form in a ring or complex internal structure rather than a solid center chain.

[Zynda]

^^This is great post. Thanks

[Amber G.]

The loss of the IRNSS-1F atomic clock reduces the number of working navigation satellites below the minimum required for full NavIC service, exposing long-standing reliability issues in the system’s atomic clocks and creating pressure for India to launch replacement satellites.. ..

India's NavIC satellite system faces challenge as IRNSS-1F failed after atomic clock malfunction: what we know

India's NavIC GPS alternative faces challenges after satellite IRNSS-1F failed, reducing operational satellites to three. A minimum of four is needed for complete coverage. The Union government last year stated that only four of the 11 satellites deployed for the NavIC system were fully operational.

[Ashokk]

IRNSS-1F successfully completed its mission life of 10 years

IRNSS-1F satellite launched in March 2016 has completed its design mission life of 10 years on 10th March 2026.

On 13th March 2026, procured on-board Atomic clock stopped functioning. However, the satellite will continue to function in-orbit for various societal applications to provide one way broadcast messaging services.

[Ashokk]

ISRO conducts sea level test of cryogenic engine at 22 tonne thrust level with full area nozzle

ISRO successfully conducted a sea level hot test of its Cryogenic engine (CE20) at 22 tonne thrust using nozzle protection system and multi-element igniter, on March 10, 2026 at ISRO Propulsion Complex, Mahendragiri. Earlier, the sea level tests utilizing nozzle protection system was being carried out at 19 tonne thrust level.

The CE20 cryogenic engine powers the upper cryogenic stage of LVM3 launch vehicle. In order to enhance the payload capability of the LVM3 vehicle, future missions of LVM3 are planned to be operated with an uprated C32 stage with 22 tonne thrust for the CE20 engine. In view of this, the flight acceptance test of the CE20 engine also needs to be conducted at 22 tonne thrust level. Therefore, the present test qualified the sea level testing of the engine with a test duration of 165 seconds at 22t thrust level using the Nozzle Protection System (NPS). The performance of the engine as well as the test facility was as expected during the entire test duration.

Testing the CE20 engine at sea-level possess considerable challenges primarily due to high area ratio nozzle, which has an exit pressure of ~50 mbar. Main concern during testing at sea-level include flow separation inside the nozzle, which leads to severe vibrations & thermal problems at the flow separation plane leading to possible mechanical damage of the nozzle.

The Cryogenic engine utilized for this test has undergone a record maximum number of hot tests (20 No.s) successfully, that has enabled the demonstration of several key technologies using a single engine such as engine ignition using multi element igniter, ignition margin demonstration for Gaganyaan over a wide range of propellants tank pressure and pre-ignition chamber pressure, engine qualification for Gaganyaan at 20 tonne thrust level, demonstration & qualification of 22tonne thrust level operation, boot-strap mode starting of CE20 engine without start-up system for enabling re-start in flight, indigenous turbopumps bearings qualification, indigenous sensor qualification and Nozzle Protection System qualification for high area ratio nozzle hot test at sea level.

[Amber G.]

IRNSS-1F successfully completed its mission life of 10 years

IRNSS-1F satellite launched in March 2016 has completed its design mission life of 10 years on 10th March 2026.

On 13th March 2026, procured on-board Atomic clock stopped functioning. However, the satellite will continue to function in-orbit for various societal applications to provide one way broadcast messaging services.

Thanks. There is a post by me and many newspapers are carrying this news. Few comments, background and updates:

- The loss of the IRNSS-1F atomic clock reduces the number of working navigation satellites below the minimum required for full NavIC service, exposing long-standing reliability issues in the system’s atomic clocks and creating pressure for India to launch replacement satellites.

• India’s regional satellite navigation system NavIC has suffered a setback after the satellite IRNSS‑1F lost its final functioning atomic clock on 13 March 2026.
  The satellite had three rubidium atomic clocks, and two had already failed earlier. When the last one stopped working, the satellite could no longer provide navigation services.
  
  With this failure, only three NavIC satellites remain capable of providing positioning, navigation, and timing (PNT) services, while at least four are required to maintain full regional navigation coverage.
  
  Although the navigation function has stopped, the satellite will continue operating in orbit for limited services, such as one-way broadcast messaging.The failure also highlights a broader reliability problem in the NavIC constellation:
  
  Out of 11 satellites launched since 2013, several have suffered failures, mostly due to malfunctions of imported rubidium atomic clocks.
  
  As a result, the constellation has become critically depleted, making it harder for NavIC to provide continuous navigation coverage.

- Launching a Second-Generation NavIC Constellation (NVS series)

ISRO is replacing the early IRNSS satellites with next-generation satellites called the NVS series.

• Planned satellites: NVS-01, NVS-02, NVS-03, NVS-04, NVS-05
  These satellites have longer lifetimes (~12 years) and improved navigation payloads.
  The first one, NVS-01, was already launched in 2023.

[/list]
- Switching to Indigenous Atomic Clocks

• The biggest technical fix is replacing imported clocks with Indian-built rubidium atomic clocks.
  
  Early NavIC satellites used imported SpectraTime clocks, and many of them failed in orbit.
  To fix this, ISRO’s Space Applications Centre (Ahmedabad) developed the Indian Rubidium Atomic Frequency Standard (IRAFS).
  First flown on NVS-01.Designed specifically to avoid the reliability issues seen in the original satellites.
  This is probably the most important engineering change in the system.

- Rebuilding the Minimum Constellation

• For navigation, you need at least four working satellites to solve for position and time.
  After the failure of IRNSS-1F, only three satellites currently provide full navigation signals, which affects service reliability.

ISRO’s strategy

• Launch additional NVS satellites
  Replace aging IRNSS spacecraft
  Restore at least 4–7 operational satellites
  The original NavIC architecture was 7 satellites (3 GEO + 4 inclined geosynchronous).

- Expanding Signals for Civil Devices

• The new satellites also add a new L1 band signal (similar to GPS L1).
  
  This is important because it allows mass-market chipsets (phones, wearables, IoT) to support NavIC more easily.
  
  Earlier NavIC signals were mainly L5 and S-band, which limited adoption.

ISRO’s response is essentially a generation replacement strategy:

Replace aging IRNSS satellites
Use indigenous rubidium atomic clocks
Launch NVS-series satellites with longer lifetimes and additional signals
Restore the minimum navigation constellation

Time Line (My take/hope):
Phase 1 — Start of Second-Generation Satellites
2023 — NVS-01 launched, First second-generation NavIC satellite.

Launched 29 May 2023 using GSLV-F12, Indian-made rubidium atomic clock and new L1 civilian signal.

Phase 2 — Early Replacement Attempts

2025 — NVS-02 launched, Second satellite in the replacement series.
However it did not reach its intended operational orbit, limiting its usefulness for navigation.

So effectively, only NVS-01 is fully contributing so far.

Phase 3 — Main Replacement Wave

ISRO plans to launch three more satellites:

NVS-03, NVS-04, NVS-05

These are intended to restore the constellation strength and replace aging IRNSS spacecraft.

Expected timeframe:
launches through 2025–2026 (some may slip slightly depending on launch cadence).
2023 - NVS-01 - operational
2025 NVS-02 launched (limited/failed due to orbit issue)
2026 NVS-03 launch
2026 NVS-04 launch
2026+ NVS-05 launch

----
For those who are more interested in Physics/technical part:

Implication

- Even with the recent atomic-clock failure in IRNSS-1F, the constellation should recover because:
- 3–4 new satellites are in the pipeline
- The new satellites have better clocks and more redundancy
- Additional atomic clocks per satellite are planned for reliability.

Realistically, NavIC should regain a stable constellation around ~2026–2027 once several NVS satellites are in place.

Technical aside (interesting GNSS detail):

NavIC satellites are GEO + inclined geosynchronous, so each satellite covers a large part of the Indian region. That means only ~7 satellites are required, unlike ~24 for Global Positioning System or ~30 for Galileo.

Amber G.

[uddu]

ISRO tests CE-20 engine at 22-tonne thrust

[Prem Kumar]

IRNSS-1F successfully completed its mission life of 10 years

What's galling is the pathetic attempt at spin-doctoring by ISRO

Yes, IRNSS-F completed 10 years. But that's not the story. The story is that we are without a working IRNSS system, our so-called answer to GPS/GLONASS

Absolute crapshow by ISRO, Minister for Space & ultimately the buck stops with Modi

And there is the sabotage angle too, which our Govt has belatedly woken up to. Many of us here have been screaming about it for years now, though some posters in this very forum tried to pooh-pooh it as some conspiracy theory

[S_Madhukar]

And decade later we are still happy only with regional navigation? So we will wait for 12 years to be sure the new atomic clocks work as expected and then we might think of a global navigation network. For all you know spoofers for the enemy and sabotage at our end must have happened in parallel

[Prem Kumar]

As someone wise said: "It takes the same amount of energy to dream big as it does to dream small"

With the corollary that the former is hugely motivating, while the latter feels limiting

We are happy dreaming small, not ruffling feathers & playing it safe. Be it "Light" combat aircraft, which must strictly be followed only by "Medium" combat aircraft. Or Agni-5's successor being only 6000 Km Agni-6 with range carefully represented as avoiding Europe. Or our homegrown LLM be specific to Indian languages/content only

We will never become a superpower because the mental shift hasn't happened yet

[Amber G.]

NavIC is clearly going through a transition period with aging satellites, and replacement launches need to accelerate.

But describing the program as a “crapshow” or suggesting sabotage ignores the technical realities of satellite lifetimes, constellation scale, and the replacement satellites already being deployed.

Let me attemptto separate three different issues that are being mixed together: the technical reality of NavIC, program management, and the political narrative.

- 1. NavIC is degraded — but it isn’t “gone”
The constellation behind NavIC is indeed partially degraded because several satellites have reached end-of-life and some had rubidium atomic-clock failures (for example IRNSS‑1F).

However that does not mean the system has disappeared:

Some satellites are still broadcasting navigation and timing signals, Receivers can still combine them with other GNSS systems, Regional timing services continue to function.

So the statement that India is “without a working IRNSS system” is technically exaggerated.

2. Satellite aging is normal for navigation constellations
GNSS satellites typically have 10–12 year design lifetimes - The first NavIC satellites were launched 2013–2016, so they are exactly entering their replacement window now.

Galileo lost atomic clocks on multiple satellites shortly after deployment.
Global Positioning System has replaced several generations (Block II, IIR, IIF, III).

The difference is scale: GPS has 30+ satellites, while NavIC has 7, so failures look more dramatic.
3. Replacement satellites are already in progress
India has already begun the second-generation NavIC replacement program:
- Several additional NVS satellites are planned
-These introduce: Indian-built atomic clocks, L1 signal compatibility with global GNSS receivers

So the program is not stalled, but mid-transition between generations.

4. “No NavIC = no navigation” is incorrect
In practice, Indian military and civilian receivers already use multi-constellation GNSS. ( Global Positioning System, GLONASS, Galileo, BeiDou, NavIC

So even during NavIC gaps, navigation capability itself is not lost.
NavIC’s real purpose is strategic autonomy, not day-to-day positioning.

5. The sabotage claim
There is no publicly verified evidence that NavIC satellite failures were caused by sabotage.

The failures reported are consistent with: 5. The sabotage claim

There is no publicly verified evidence that NavIC satellite failures were caused by sabotage.

The failures reported so far are consistent with atomic clock reliability problems, which have occurred in other GNSS programs.

Until evidence appears, the sabotage narrative is speculation.

6. The “dreaming small” argument

This is more philosophical than technical.
-NavIC was intentionally designed as a regional system, not a global one, because:
-it required 7 satellites instead of ~30
-it cost an order of magnitude less
-it covered the region India actually needed.

Whether India should eventually build a global constellation is a policy question, not necessarily a technical failure.

[Amber G.]

What's galling is the pathetic attempt at spin-doctoring by ISRO

FWIW: For me, there are a few misconceptions stand out in those comment that people familiar with GNSS systems/Physics would right away notice. Let me expand it here:

1. Confusing “regional GNSS” with “inferior GNSS”
(It assumes that because NavIC is not global like Global Positioning System or GLONASS, it reflects a “small ambition”).

Misunderstanding the design philosophy.
NavIC was intentionally designed as a regional system: (~7 satellites instead of ~24–30, dramatically lower cost.

A global constellation would require roughly: (24–30 satellites, continuous replenishment launches global ground control infrastructure.)

Even large space powers took decades to build that scale.. Galileo required >€10 billion and 20+ years to reach near-full capability.

So NavIC’s regional design was a deliberate engineering trade-off, not a sign of “dreaming small”.


2. Assuming satellite failures mean the system concept failed
The comment treats the failure of satellites like IRNSS-1F as proof the entire system is a failure.

But early-generation failures are common in GNSS programs.
-Galileo had multiple atomic clock failures shortly after launch.
-Early Global Positioning System satellites had design problems and short lifetimes.

What matters is whether the program iterates and improves, which is exactly what the NVS replacement satellites are meant to do (new clocks, new signals, longer lifetimes).

So the current situation reflects a normal first-generation learning curve, not necessarily a systemic collapse.

In short that comment mixes up two things:

Regional design ≠ lack of ambition (it was a cost-optimized architecture).
First-generation satellite failures ≠ program failure (most GNSS constellations went through similar phases).

A more subtle misconception hidden in that comment that physicists or navigation engineers often notice immediately — it relates to how GNSS redundancy works and why a 7-satellite system always looks “fragile” compared with a 30-satellite one even when functioning exactly as designed.

The third misconception is about redundancy and scale in navigation constellations. The criticism assumes that if a few satellites fail, the system must be badly designed. But that misunderstanding comes from comparing very different constellation architectures.

- Global GNSS systems are massively redundant
GPS → ~31 operational satellites
GLONASS → ~24 satellites
Galileo → ~28 satellites.

A user typically sees 8–12 satellites simultaneously.

So if 2–3 satellites fail, the system still works perfectly.
The failures are absorbed by redundancy.

- NavIC was intentionally built with minimal satellites
- In contrast, NavIC was designed around seven satellites:

- 3 geostationary (GEO)
-4 inclined geosynchronous (IGSO).

Because these satellites remain over the same region, each one carries much more geometric importance.
A user may see only 4–5 satellites at a time.
So losing even one or two satellites can immediately affect navigation availability.
This does not necessarily mean the design failed — it simply reflects a low-redundancy architecture.

The advantage of this architecture was:
much lower cost, continuous coverage over India, strong signals for regional users, fewer launches needed.
Instead of building a global infrastructure, India built a regional navigation layer.



Because NavIC has only a few satellites, every failure becomes very visible.

If GPS loses one satellite, nobody notices.
If NavIC loses one satellite, the system may temporarily fall below ideal geometry.

The criticism implicitly assumes NavIC should behave like a 30-satellite global system.
But NavIC was designed as a 7-satellite regional system, so its redundancy and failure tolerance are inherently different.

For technical side, there is actually one legitimate criticism buried inside the debate that Indian engineers quietly acknowledge: the rubidium atomic clock reliability problem in the early NavIC satellites. That’s a genuinely interesting engineering story involving imported space clocks and qualification issues.. We talked about that earlier..

- Amber G.

[Amber G.]

Let me also comment for BRF's interests:

Even if NavIC temporarily drops below its ideal constellation size, India’s military navigation is not crippled, because it relies on layered systems:

We use: Multi-GNSS (GPS, GLONASS, etc.) Still have NavIC encrypted military signals, Inertial navigation systems, Ground augmentation networks, and Networked battlefield navigation ityadi..

It is no secret that there is clever workaround that still lets the military use NavIC effectively even if the constellation temporarily drops below ideal navigation geometry.

The trick is to use the satellites primarily as a precise timing reference, while position is obtained by other sensors.
Navigation in may ways fundamentally a timing problem --. You do NOT always need 4 satellites (If an accurate internal clock, or a separate position estimate)

Military platforms already know their position approximately (Inertial navigation systems, terrain matching etc).
GNSS then mainly provides clock synchronization and drift correction.

GEO satellites (RNSS-1C and IRNSS-1D.) are excellent timing beacons. This makes them ideal as regional timing transmitters.

So our military uses - ( even one or two NavIC satellites, systems can still do useful things_

Precision weapons (Navigate via INS, Periodically correct clock drift from NavIC timing signals, This dramatically reduces accumulated navigation error.


So accuracy of Missiles, UAV swarm coordination remain same.

(Drones need synchronized clocks for: data links cooperative targeting radar timing0

IOW: A NavIC satellite provides a common time reference. Secure battlefield timing

And these Timing signals support: encrypted communications radar networks electronic warfare systems.

Even if navigation accuracy degrades, timing remains extremely valuable.

6. A strategic advantage of NavIC's design Because several NavIC satellites are geostationary, India effectively has:

a regional atomic clock network in space.


NavIC’s fixed satellites provide continuous coverage of the same region, which is actually excellent for regional timing services.

In short:

Even if NavIC temporarily loses some navigation satellites:
its GEO satellites can still provide precise timing
military systems combine that with inertial navigation
weapons and platforms retain high accuracy

[Kanoji]

Let me also comment for BRF's interests:

Thank you Amber G ji for putting things in perspective. Very informative for mango people like me.

[Tanaji]

The launch cadence of ISRO has gone down after Covid which is worrying. We need a lower cost per kg to get to space and one that has quick turnaround time. The latter will be important if in war the enemy takes out satellites. This is only possible if we have a reusable booster. We dont need one in Starship class, PSLV G would be something to target . I am aware ISRO is looking into it but this needs to be higher priority…. The earlier argument that we are already cheap or our needs do not require a reusable launcher are no longer valid.

[Prem Kumar]

Amber G: you are putting lipstick on a pig. The failure to maintain enough satellites in orbit for a regional navigation system is a program management failure. Aided no doubt by sabotage and/or technical failures in launch systems. But in spite of launch failures, Plan B & C should have been in place - to use non-Indian launch vehicles

Having redundant systems like INS, MINGS etc doesn't hide the above failure

Having a somewhat-working but degraded NavIC doesn't hide the above failure. Its like AWS saying that users will experience outages & high latency, "but hey - some servers are working - so, we are not fully down!"

*******************

On a different note, I noticed a undercurrent in your posts across forums. There is no easy way to say this - so I will just say it straight. You seem to argue against people who point out to Indian inadequacies, which seems supportive at the surface. But I wonder if this isn't far more damaging to preparedness - being lulled into a false sense of complacency. I noticed this also in the Nuclear thread, where you opposed renewed testing, claiming that "simulations are enough", though India doesn't have 1/100th the data-points that US or USSR does (& even they think more testing is required)

Do you want Indian ambitions & capabilities curtailed and Indians being lulled with a sense of "look at what we have achieved. Lets dream no bigger"?

I don't know if your posts have this tone by design or if its accidental. Either way, they are damaging

I apologize if this is hurtful, but I need to know where you stand

*******************

None of this takes away from the high quality of your posts, especially in the Math forum, which I thoroughly enjoy

[Amber G.]

^^^@Kanoji, @Tanaji & @Prem Kumar - Thanks for your feedback. Some comments:

One important point, I agree with : constellation management is ultimately a program responsibility. For a regional system like NavIC, where margins are tight, delays in replacement launches and the IRNSS-1H failure did leave the system more exposed than it should have been. A more aggressive replenishment strategy—or faster contingency launches—would have reduced today’s gap. That’s a fair criticism.

Where I disagree is in calling the system a “failure” or invoking sabotage without evidence. What actually happened is much more mundane and well-understood: atomic clock reliability issues (as seen on IRNSS-1F and earlier satellites) combined with first-generation lifecycle timing. Even Galileo had similar clock failures early on. The difference is scale—NavIC’s small constellation makes every loss visible. That’s a design trade-off, not necessarily mismanagement.

On the “Plan B using foreign launchers” point: in principle, yes, that’s an option. In practice, for a strategic system tied to sovereignty, countries tend to avoid dependence on external launch providers except in extremis. It’s a trade-off between schedule robustness and strategic autonomy, not an obvious oversight.

The AWS analogy doesn’t quite fit either. Cloud systems are designed for near-zero downtime via massive redundancy. NavIC was explicitly designed as a low-cost regional system with minimal satellites, so it cannot have the same fault tolerance. It’s closer to a small, high-performance cluster than a hyperscale cloud.

On the broader point about “downplaying inadequacies”:

There’s a difference between denying problems and characterizing them correctly.

If there is a genuine engineering or program gap, it should be called out clearly (and here, the clock reliability and replenishment cadence are real issues).

But if something is being framed as a systemic collapse or conspiracy, when it’s actually a known technical failure mode, that needs correcting too.

Overstating failure can be just as misleading as understating it.

On nuclear testing / “simulations are enough” (since you mentioned it):

That’s a separate technical debate, and reasonable experts disagree. The key point there isn’t “no more testing ever,” but that modern stockpile stewardship combines legacy test data + simulation + subcritical experiments. Whether India has “enough data” is a quantitative question, not something that can be settled by analogy to the US or USSR alone.

IOW:

->Yes, there are program management lessons here (especially replacement timing).
->No, this is not a collapse or sabotage-driven failure—it’s a first-generation system hitting known technical limits.
-> And being precise about that is not about lowering ambition—it’s about understanding where to fix things properly.

Amber G.

[bala]

In terms of ISRO and India the issue is that India is not serious about catching up to the other 4 - US, Russia, China and EU. In every area India is lagging behind, though in some like Moon and Mars they are not too behind. India / ISRO require better powered rockets and a more frequent launching schedule which needs to happen in clockwork fashion with very very few failures. The PMO has to 10x the budgets for ISRO, DRDO, BARC. We need to think big because getting to #3 in the world requires stepping up big time. If you don't invest now then you will be in catch mode forever. Navic full fledged and worldwide is required, let us get past these regional junk.

[pravula]

This would be ideal opportunity to test out if we have any capacity to replace degraded/burnt up satellites during our scrimmages. Weren’t Agni series supposed to be able to launch satellites? Let’s see them deploy

[Amber G.]

This would be ideal opportunity to test out if we have any capacity to replace degraded/burnt up satellites during our scrimmages. Weren’t Agni series supposed to be able to launch satellites? Let’s see them deploy

That’s not really how it works. Agni series aren’t substitute launch vehicles for operational satellite deployment, and “scrimmage launches” aren’t a thing for maintaining a navigation constellation.

Also NavIC satellites with failed clocks aren’t “dead”; they’re still usable for messaging (e.g., weather/disaster alerts) even if not for precise navigation.

[pravula]

This would be ideal opportunity to test out if we have any capacity to replace degraded/burnt up satellites during our scrimmages. Weren’t Agni series supposed to be able to launch satellites? Let’s see them deploy

That’s not really how it works. Agni series aren’t substitute launch vehicles for operational satellite deployment, and “scrimmage launches” aren’t a thing for maintaining a navigation constellation.

Also NavIC satellites with failed clocks aren’t “dead”; they’re still usable for messaging (e.g., weather/disaster alerts) even if not for precise navigation.

You are missing the point of my comment. In a war, these nav satellites are going to be targeted and degraded. What is our plan? Just operate without them or launch replacements? If the first, then fine. If the second, we will have to launch from Agni series and the sats launched should be effective in what they do. This would be the time to test the full system imho.

[Tanaji]

NavIC issues could have been mitigated if we were capable of at the very least a higher launch cadence even without a reusable booster. A reusable booster allows us to overcome lack of resiliency that the NavIC was designed with as we could launch on short notice.

The NavIC thing is gross management failure as the resiliency constraints of the design were known at beginning. The programme should have allocated reserve launch funds and contingency sats at the outset itself. The situation now is that we cant launch more than 4-5 times a year, if that!

Our habit of dreaming of Chateau Rothschild wine using arrack money means neither do we enjoy arrack and nor do we get Chateau Rothschild. To top it all we justify it with jhugaad analogy.

To be fair, DoS needs more budget allocation but “laadli bahens” need to be funded so here we are.

[drnayar]

That’s not really how it works. Agni series aren’t substitute launch vehicles for operational satellite deployment, and “scrimmage launches” aren’t a thing for maintaining a navigation constellation.

Also NavIC satellites with failed clocks aren’t “dead”; they’re still usable for messaging (e.g., weather/disaster alerts) even if not for precise navigation.

You are missing the point of my comment. In a war, these nav satellites are going to be targeted and degraded. What is our plan? Just operate without them or launch replacements? If the first, then fine. If the second, we will have to launch from Agni series and the sats launched should be effective in what they do. This would be the time to test the full system imho.

Apparently there is a DRDO satellite launcher , why not use these for LEO satellites

[S_Madhukar]

…

Our habit of dreaming of Chateau Rothschild wine using arrack money means neither do we enjoy arrack and nor do we get Chateau Rothschild. To top it all we justify it with jhugaad analogy.

To be fair, DoS needs more budget allocation but “laadli bahens” need to be funded so here we are.

Couldn’t have said better !
This is exactly why despite NM’s personal equations western media not withstanding their lefty leanings doesn’t take us seriously. If I am a scientist or defence expert or university student in the West I would honestly question the lack of upward trajectory of our space milestones.

You crow you are the 4th largest economy yet the funding pattern matches a geriatric EU paying benefits instead of a young prowling China that wants to go places. We don’t even want to be #2 in Asia it seems.
Gandhian fasts on Sunday when you should be feasting on high quality nutrition to get ready for the week ahead !
Fits and starts and sudden stops does not give confidence.

The only explanation I think I see is Chinese sent an astronaut in 2003 and completed GPS in 2020s having started regional navigation around same time … that might make some think Gaganyaan should top all funding… mirroring China

[Amber G.]

That’s not really how it works. Agni series aren’t substitute launch vehicles for operational satellite deployment, and “scrimmage launches” aren’t a thing for maintaining a navigation constellation.

Also NavIC satellites with failed clocks aren’t “dead”; they’re still usable for messaging (e.g., weather/disaster alerts) even if not for precise navigation.

You are missing the point of my comment. In a war, these nav satellites are going to be targeted and degraded. What is our plan? Just operate without them or launch replacements? If the first, then fine. If the second, we will have to launch from Agni series and the sats launched should be effective in what they do. This would be the time to test the full system imho.

I’m not missing the point—I’m correcting the technical premise. NavIC is a first-generation regional GNSS; degraded ≠ useless, and some satellites still support timing/messaging (e.g., alerts) even if navigation is affected.

Using Agni series as a stand-in launch system isn’t a meaningful “Plan B”—that’s not how operational satellite replacement works. Wartime resilience comes from multi-GNSS use, INS backup, and planned replenishment launches, not improvised missile deployments.

“Test the full system” sounds good, but it has to be technically coherent—not just a slogan.

*****
On a broader point—I’m not arguing against criticism; I’m pushing back on technically incorrect criticism. Valid shortcomings (like clock reliability or replacement cadence in NavIC) absolutely should be called out. But misframing or exaggeration doesn’t improve preparedness—it obscures what actually needs fixing. I’m firmly pro-science and pro-capability: get the diagnosis right, and you get better outcomes—for India or anyone else.

You seem to argue against people who point out to Indian inadequacies, ...

...Do you want Indian ambitions & capabilities curtailed and Indians being lulled with a sense of "look at what we have achieved. Lets dream no bigger"?

I don't know if your posts have this tone by design or if its accidental. Either way, they are damaging

- Amber G. - pro-science, pro-capability, and precise about the facts.

[Amber G.]

NavIC issues could have been mitigated if we were capable of at the very least a higher launch cadence even without a reusable booster. A reusable booster allows us to overcome lack of resiliency that the NavIC was designed with as we could launch on short notice.

The NavIC thing is gross management failure as the resiliency constraints of the design were known at beginning. The programme should have allocated reserve launch funds and contingency sats at the outset itself. The situation now is that we cant launch more than 4-5 times a year, if that!
<snip>

There’s a fair point about replenishment cadence—a small constellation like NavIC does need on-orbit spares or faster replacement. But calling it a “gross management failure” is overstated. This is a first-generation system hitting known reliability and lifecycle limits, not a fundamentally flawed design.

For those with longer memory—during the Kargil War, India had no independent navigation or even real-time satellite imaging. The U.S. restricted access to Global Positioning System data, and India had to rely on limited alternatives via Russia and Israel for imagery and support.

From that position to building NavIC and an indigenous space-based PNT capability—even with current gaps—is a significant strategic shift.

Also, reusability isn’t the main lever here—cadence comes from satellite production, integration flow, and launch planning, not just the booster type. You can increase launch rate with expendables if the pipeline exists.

So yes—better contingency planning (spares, cadence) would have helped. But this is normal iteration on an initial architecture, not evidence that the design itself was a failure.

[Amber G.]

<snip>
Apparently there is a DRDO satellite launcher , why not use these for LEO satellites

AFAIK - There is no operational “DRDO satellite launcher”—you’re mixing up ASAT/missile tech with orbital launch, which are completely different problems; all Indian satellites are still launched via ISRO vehicles, not missiles.

(What some people refers is likely DRDO’s missile/ASAT capability, demonstrated in Mission Shakti. That used a modified interceptor missile to destroy a satellite in LEO—not to launch one.

- ASAT / ballistic missiles → intercept or destroy objects
- Launch vehicles (ISRO PSLV/GSLV) → place satellites into stable orbit

(Turning the former into a reliable orbital launcher is non-trivial and not operationally done.

Also - DRDO has built satellites (e.g., EMISAT) but these were launched by ISRO rockets, not DRDO systems.

[pravula]

You are missing the point of my comment. In a war, these nav satellites are going to be targeted and degraded. What is our plan? Just operate without them or launch replacements? If the first, then fine. If the second, we will have to launch from Agni series and the sats launched should be effective in what they do. This would be the time to test the full system imho.

I’m not missing the point—I’m correcting the technical premise. NavIC is a first-generation regional GNSS; degraded ≠ useless, and some satellites still support timing/messaging (e.g., alerts) even if navigation is affected.

Using Agni series as a stand-in launch system isn’t a meaningful “Plan B”—that’s not how operational satellite replacement works. Wartime resilience comes from multi-GNSS use, INS backup, and planned replenishment launches, not improvised missile deployments.

“Test the full system” sounds good, but it has to be technically coherent—not just a slogan.

*****
On a broader point—I’m not arguing against criticism; I’m pushing back on technically incorrect criticism. Valid shortcomings (like clock reliability or replacement cadence in NavIC) absolutely should be called out. But misframing or exaggeration doesn’t improve preparedness—it obscures what actually needs fixing. I’m firmly pro-science and pro-capability: get the diagnosis right, and you get better outcomes—for India or anyone else.

You seem to argue against people who point out to Indian inadequacies, ...

...Do you want Indian ambitions & capabilities curtailed and Indians being lulled with a sense of "look at what we have achieved. Lets dream no bigger"?

I don't know if your posts have this tone by design or if its accidental. Either way, they are damaging

- Amber G. - pro-science, pro-capability, and precise about the facts.

Nonsense. If a Nav cluster cannot provide Nav info, then it is useless for the job. It can still send some memes, jump up/down and relay eggplant emojis / MMS messages, but its useless for its task.

If we do not have a plan to launch under sat denial, then, we suck. FWIW, I think we have a plan to do so, I just dont know what it is if Agni series is not it.

[uddu]

I’m not missing the point—I’m correcting the technical premise. NavIC is a first-generation regional GNSS; degraded ≠ useless, and some satellites still support timing/messaging (e.g., alerts) even if navigation is affected.

Using Agni series as a stand-in launch system isn’t a meaningful “Plan B”—that’s not how operational satellite replacement works. Wartime resilience comes from multi-GNSS use, INS backup, and planned replenishment launches, not improvised missile deployments.

“Test the full system” sounds good, but it has to be technically coherent—not just a slogan.

*****
On a broader point—I’m not arguing against criticism; I’m pushing back on technically incorrect criticism. Valid shortcomings (like clock reliability or replacement cadence in NavIC) absolutely should be called out. But misframing or exaggeration doesn’t improve preparedness—it obscures what actually needs fixing. I’m firmly pro-science and pro-capability: get the diagnosis right, and you get better outcomes—for India or anyone else.



- Amber G. - pro-science, pro-capability, and precise about the facts.

Nonsense. If a Nav cluster cannot provide Nav info, then it is useless for the job. It can still send some memes, jump up/down and relay eggplant emojis / MMS messages, but its useless for its task.

If we do not have a plan to launch under sat denial, then, we suck. FWIW, I think we have a plan to do so, I just dont know what it is if Agni series is not it.

It seem to be a new missile
https://imp.news/space/veda-unmasked-in ... ion-80648/

[Amber G.]

.....
It seem to be a new missile
https://imp.news/space/veda-unmasked-in ... ion-80648/

Thanks. Good that you brought this up—BUT IMO “Project VEDA” sits right at the intersection of fact and hype.

In short - VEDA-type concepts (if real) are about small, rapid LEO launches, not a substitute for full-fledged orbital launch vehicles. There’s no evidence it’s operational yet, and certainly nothing deployed in real scenarios. It’s a future contingency capability, not something you can assume exists today

If interested my take - What’s likely real (in principle):

- There are credible reports of a DRDO concept called VEDA (Vehicle for Defence Application):

A mobile, solid-fuel rocket derived partly from missile tech
Intended for rapid/on-demand launch of small military satellites
(Possibly LEO payload ~1–2 tons (if it matures) - Conceptually, this fits a known military need)
==> “responsive space” / rapid reconstitution after ASAT attack

So the idea itself is not crazy. .. But here’s the reality check

Almost everything one is seeing (including that article) is:
-unofficial / speculative / loosely sourced
-not confirmed as an operational capability
-not demonstrated in real missions yet

(IOW 0 no evidence that, it has reached reliable orbital launch status or it can replace ISRO launch vehicles today
Key important technical nuance
(Even if VEDA exists / not out in open)

-It would be a small, responsive launcher, Not a replacement for PSLV/GSLV-class precision orbital insertion

Most likely limited to: LEO - small satellites - quick-and-dirty deployments

(It may complements—but does NOT replace—mainstream launch capability.)

The idea (rapid wartime launch) is valid and globally pursued - But even USA ( I am *very* familiar with) -is not advance (see note for perspective):

And it still doesn’t change the core point -
==> orbital launch ≠ missile launch, even if they share technology (Many things are different)

---
For perspective check out TacRL2 (2021)
The U.S. has been working on rapid launch for years under the United States Space Force and Defense Advanced Research Projects Agency.

It says Rocket launched within ~3 weeks of call-up
Demonstrated real “responsive launch”- Small payloads, quick turnaround

Still not “launch in hours” Requires pre-built satellites + ready rockets

==> Even the most advanced system is logistics-limited, not just rocket-limited

[Amber G.]

For those who are interested - Physics/technology wise why a missile launcher can not be used for satellite ?

Because the requirements are fundamentally different: a missile delivers a payload on a ballistic trajectory, whereas a satellite launcher must provide precise orbital insertion (velocity + direction) and a controlled final stage. Missiles lack the guidance precision, staging control, and payload environment needed for stable orbit—so using something like the Agni series as a satellite launcher isn’t practical.

[Amber G.]

<snip>
Nonsense. If a Nav cluster cannot provide Nav info, then it is useless for the job. It can still send some memes, jump up/down and relay eggplant emojis / MMS messages, but its useless for its task.

If we do not have a plan to launch under sat denial, then, we suck. FWIW, I think we have a plan to do so, I just dont know what it is if Agni series is not it.

“Nonsense” is dismissing the basics. A degraded NavIC isn’t “useless”—loss of navigation ≠ loss of function; satellites can still provide timing and messaging, which are operationally relevant. And no, the Agni series isn’t a plug-and-play satellite launcher. Push back is fine—but it should be grounded in how the system actually works, not in caricatures.

[pravula]

<snip>
Nonsense. If a Nav cluster cannot provide Nav info, then it is useless for the job. It can still send some memes, jump up/down and relay eggplant emojis / MMS messages, but its useless for its task.

If we do not have a plan to launch under sat denial, then, we suck. FWIW, I think we have a plan to do so, I just dont know what it is if Agni series is not it.

“Nonsense” is dismissing the basics. A degraded NavIC isn’t “useless”—loss of navigation ≠ loss of function; satellites can still provide timing and messaging, which are operationally relevant. And no, the Agni series isn’t a plug-and-play satellite launcher. Push back is fine—but it should be grounded in how the system actually works, not in caricatures.

I will have to disagree. You seem to have a view that if the sat can do anything, like perform a lungi dance, then is useful. For me, it’s a failure.

[Prem Kumar]

“Nonsense” is dismissing the basics. A degraded NavIC isn’t “useless”—loss of navigation ≠ loss of function; satellites can still provide timing and messaging, which are operationally relevant. And no, the Agni series isn’t a plug-and-play satellite launcher. Push back is fine—but it should be grounded in how the system actually works, not in caricatures.

These kinds of posts are why you appear to miss the point, either unintentionally or deliberately

NavIC is dead, or at least crippled. Its useless for missile navigation. Its shameful that we let it come to this

This is the simple truth. No amount of 1000 word explanations are going to change this basic fact

[drnayar]

FOBS ?
Dedicated launcher for spy sats ?