Indian Space Program: News & Discussion

[KL Dubey]

Upto now the expectations on ISRO have been the following:
1. Provide domestic launch and satellite capabilities for strategic/ military programs which at least in theory cannot be outsourced
2. Provide domestic launch and satellite capabilities for commercial applications ( communications/ remote sensing )
3. Provide domestic capabilities for scientific research, Mars missions, humans in space, etc. ( non-commercial applications )

In the coming years, 1. sector will be eaten away by DSA, 2. sector will be eaten away by SpaceX/China or Indian private sector companies, ISRO will be left only with 3. which are always derided as white elephant/ vanity projects. And that is not a good place to be in. Hope the folks can see the writing on the wall and act in a more competitive manner to ensure future survival of the organization.

Your post is substantive and well written.

- I agree with the Dept of Space assessment ("Amber G" posted) that India will likely be a significant player in the space economy.

- However, I don't understand why ISRO has to become a "competitive" entity. It is not a private company or even a PSU, it's a government space research agency like NASA in the US, that adheres to the government's policy mandates.

- Yes, it is good that Bharat Sarkar has created DSA for routine operations (and presumably launches) of military assets. I am guessing ISRO does not need to do this any more.

- Yes, it will be great if Indian private sector steps up for vehicle and satellite production for military and commercial launches, in collaboration with ISRO and DSA.

- Yes, I am assuming ISRO will transition into the most challenging R&D that can't be done by application-focused organizations/companies, i.e. new vehicles (including reusable), moon/planetary exploration, manned space program, etc. The technology produced by ISRO would be expected to have a key advantage of low cost and reliable, like those they have already produced.

[Najunamar]

I was hearing a lot on how miniaturization will make all but the manned or interplanetary planetary missions less reliant on development of bigger rockets, is that no longer the case? Number 2, even if reusability of first stage plays a key role in reducing the cost of satellite launches, is the delta so big that ISRO is uncompetitive/ headed that way? I am surprised by the pessimistic statements in this board when just a few months back we were told India is making significant inroads into this lucrative market.

[SSSalvi]

8 Seeds germinate aboard PSLV C60 POEM -4:

https://www.youtube.com/watch?v=SidrS6NXuo4

[suryag]

am eagerly waiting for the Jan7th rendezvous/spadex experiment, JSR to that

[Amber G.]

I was hearing a lot on how miniaturization will make all but the manned or interplanetary planetary missions less reliant on development of bigger rockets, is that no longer the case? Number 2, even if reusability of first stage plays a key role in reducing the cost of satellite launches, is the delta so big that ISRO is uncompetitive/ headed that way?

FWIW: Miniaturization is indeed reducing the need for bigger rockets, (except for manned or interplanetary missions). Advances in technology have enabled smaller satellites and payloads, making launch vehicles like the SSLV) more viable.

However, reusability remains a crucial factor in reducing launch costs. While ISRO has made significant progress in reusability, particularly with RLV technology, the cost savings might not be substantial enough to offset the advantages of other launch providers.

But IMO ISRO is still competitive in the global launch market, especially with its reliable workhorse, the PSLV. India's has demonstrating its capabilities and cost-effectiveness .

Private players like Skyroot Aerospace and Agnikul Cosmos are innovating ...

So, while there might be concerns ...I would say .. ISRO's advancements in miniaturization, reusability, and international collaborations remains a significant player in the global space industry.

[SSSalvi]

am eagerly waiting for the Jan7th rendezvous/spadex experiment, JSR to that

Postponed to 9th.


https://twitter.com/isro/status/1876191202967785774

The SpaDeX Docking scheduled on 7th is now postponed to 9th.
The docking process requires further validation through ground simulations based on an abort scenario identified today.

[csaurabh]

I was hearing a lot on how miniaturization will make all but the manned or interplanetary planetary missions less reliant on development of bigger rockets, is that no longer the case? Number 2, even if reusability of first stage plays a key role in reducing the cost of satellite launches, is the delta so big that ISRO is uncompetitive/ headed that way? I am surprised by the pessimistic statements in this board when just a few months back we were told India is making significant inroads into this lucrative market.

Small satellite launch vehicles aren't as cost effective as you might think.
A launch on a small satellite launcher like Rocketlab Electron, costs ~20,000 $/kg, while on Falcon 9 it would cost $6,000/kg.

Why? It is kind of the same reason why a bus carrying 50 people is more cost efficient than a car carrying 5 people. Big launch vehicles are more cost effective than small launch vehicles. It means that even if the satellites get miniaturized, they still go on the bigger launchers, just on a sharing basis, rather than a dedicated launch just for them.

The problem with that method is that satellites get dumped into a random orbit based on the ride-share rather than where they actually want to go. But for many this is not a big problem compared to the cost effectiveness.

[Amber G.]

^^^^

I was hearing a lot on how miniaturization will make all but the manned or interplanetary planetary missions less reliant on development of bigger rockets, is that no longer the case? Number 2, even if reusability of first stage plays a key role in reducing the cost of satellite launches, is the delta so big that ISRO is uncompetitive/ headed that way? I am surprised by the pessimistic statements in this board when just a few months back we were told India is making significant inroads into this lucrative market.

Small satellite launch vehicles aren't as cost effective as you might think.
A launch on a small satellite launcher like Rocketlab Electron, costs ~20,000 $/kg, while on Falcon 9 it would cost $6,000/kg.

Why? It is kind of the same reason why a bus carrying 50 people is more cost efficient than a car carrying 5 people. Big launch vehicles are more cost effective than small launch vehicles. It means that even if the satellites get miniaturized, they still go on the bigger launchers, just on a sharing basis, rather than a dedicated launch just for them.

The problem with that method is that satellites get dumped into a random orbit based on the ride-share rather than where they actually want to go. But for many this is not a big problem compared to the cost effectiveness.

That's a valid point about economies of scale in launch vehicles. However, cost-effectiveness depends on various factors beyond just the launch vehicle's size.

For instance, consider why people prefer driving cars to work over taking buses - (I and virtually everyone here uses a car when they go to work). While buses might be more cost-effective for transporting large groups, cars offer flexibility, convenience, and personalized routes. Many people value these benefits over the cost savings of bus travel.

Similarly, in satellite launches, factors like mission requirements, orbit specificity, launch schedule, and payload constraints can make dedicated launches on smaller vehicles more attractive than ride-sharing on larger ones.

So the statement's accuracy depends not only on the current market prices and the specific launch services being compared. Here's a breakdown:

Rocket Lab's Electron launch vehicle: The cost per kilogram, as you said, is around $20,000-$30,000. However, this price can vary depending on the specific mission requirements, launch frequency, and other factors.

SpaceX's Falcon 9 launch vehicle: The cost per kilogram is indeed lower, around $6,000-$8,000, but this is often for a dedicated launch with a high-mass payload. For smaller payloads or rideshare missions, the cost per kilogram can be higher.

But - It's essential to note that small satellite launch vehicles like Electron offer dedicated launches for smaller payloads, providing more flexibility and control over the launch schedule. In contrast, larger launch vehicles like Falcon 9 often require smaller satellites to share the ride with larger payloads, which can lead to scheduling constraints and less flexibility.

So it all depends on the specific launch services and requirements being compared.

Added later: For perspective (quick google search):

Arianespace (Europe): The cost of launching payloads on Arianespace's Ariane 5 rocket is around $20,000 to $30,000 per kilogram to Geostationary Transfer Orbit (GTO) .
United Launch Alliance (USA): ULA's Atlas V rocket has a cost of around $10,000 to $20,000 per kilogram to LEO .
China Great Wall Industry Corporation (China): The cost of launching payloads on China's Long March rockets is around $10,000 to $20,000 per kilogram to LEO .
ISRO offers a competitive pricing of around $3,000 to $5,000 per kilogram to LEO .

[Amber G.]

New ISRO chairman Shri V Narayanan, Director LPSC


-- A good choice.
Dr. V Narayanan is a distinguished scientist and Director of the Liquid Propulsion Systems Centre (LPSC) at ISRO. He has played a crucial role in developing India's cryogenic propulsion systems, including the GSLV and the Chandrayaan-2 mission.

An alum of IIT (Kharagpur), recipient of several honors and has published extensively and delivered keynote speeches at various conferences and institutions.

[SSridhar]

While making a maneuver to reach 225 m between satellites the drift was found to be more than expected, post non-visibility period. The planned docking for 9th January 2024, is postponed. Satellites are safe - ISRO

[Ashokk]

https://x.com/isro/status/1877359114117885953

The drift has been arrested and spacecrafts put in a slow drift course to move closer to each other. By tomorrow, it is expected to reach initialisation conditions.

[Ashokk]

https://x.com/s2a_systems/status/1877342140939825286

Today’s SpaDeX pass over Australia. Recorded on 2025-01-09, 11:46:09 UTC. Estimated distance between the two spacecraft near max elevation was about 4.6 km.
Two light curves generated last night during the pass over South America between 02:19 and 02:17 UTC indicate that attitude control is intact for both satellites, which is consistent with the latest ISRO communication on X stating that the satellites are safe.

[Ashokk]

https://x.com/s2a_systems/status/1877636459663859857

SpaDeX A and B on 2025-01-10, 08:29:20 UTC. Estimated distance between the two spacecraft: about 1.5 km.

[SSridhar]

https://x.com/isro/status/1878057697070743897: (6:03 PM Jan 11, 2025)

SpaDeX Status Update:

Arrested at Inter Satellite Distance (ISD) of 230 m, all sensors are being evaluated. Spacecraft's health is normal.

[SSridhar]

https://x.com/isro/status/1878227290435604782 (5:17 AM Jan. 12, 2025)
SpaDeX Docking Update:

At 15m we see each other clearer and clearer, we are just 50 feet away for an exciting handshake

[SSridhar]

Another quick update from ISRO.

https://x.com/isro/status/1878254580825497776 (7:06 AM, Jan. 12, 2025)
SpaDeX Docking Update:

A trial attempt to reach up to 15 m and further to 3 m is done.

Moving back spacecrafts to safe distance

The docking process will be done after analysing data further.

Stay tuned for updates.

[prasannasimha]

We have to see if they do it this evening but looks unlikely. We may have to wait for the proximity sensor validation /recalibration for the less than 3-meter rendezvous before docking as this has to be a fully automated docking sequence

[drnayar]

i suppose all the encounters with docking attempts would generate a lot of data for future programmes than the very first attempt being successful ?

[suryag]

ohhh yes, we had terrible experience with our sensor suite when we were trying a similar system. WE used a combination of nfc, uwb and hall effect sensor for the final close proximity approach, why so many sensors ? well reliability wasnt uniform across and we needed multiple redundancies built in to take care of noise generated. In this particular case, am sure they are getting all that data back to base(god knows how behaviours change in space

[Ashokk]

https://x.com/s2a_systems/status/1878723791213441031

SpaDeX A & B on 2025-01-13, 08:33:51 UTC over South America. Estimated distance between the two spacecraft near max elevation: ~2.6 km.

[Ashokk]

ISRO's SpaDeX Satellites Docking Experiment May Get Delayed Till March

In the SpaDeX project, the two satellites have been placed in a low orbit and are travelling with a speed of 7 km per second. Now according to the experts, the problem with low flying satellites is that the spacecrafts position keeps changing with the earth's rotation, which further complicates the tracking tasks for the scientists.
As position keeps shifting, there is hardly a 15-20 minute window for the docking move.
Though the parameters up in the sky may allow the docking process for next few days, but if delayed for a longer period, the next favourable cycle may not arrive until March.

[Amber G.]

ISRO's SpaDeX Satellites Docking Experiment May Get Delayed Till March

In the SpaDeX project, the two satellites have been placed in a low orbit and are travelling with a speed of 7 km per second. Now according to the experts, the problem with low flying satellites is that the spacecrafts position keeps changing with the earth's rotation, which further complicates the tracking tasks for the scientists.
As position keeps shifting, there is hardly a 15-20 minute window for the docking move.
Though the parameters up in the sky may allow the docking process for next few days, but if delayed for a longer period, the next favourable cycle may not arrive until March.

To add/clarify/summarize the above ...(Hope this helps)

ISRO's SPADEX satellite docking experiment, initially planned for January, may be delayed until March due to orbital constraints. The experiment involves docking two satellites, SPADEX-1 and SPADEX-2, in a low Earth orbit (LEO). However, the current orbital positions of the satellites are not favorable for docking, and ISRO is waiting for a suitable window to perform the experiment. (Technically delay no big deal)

From an orbital mechanics perspective, the challenge lies in synchronizing the orbits of the two satellites to enable a safe and controlled docking maneuver. ISRO is likely waiting for a time .. for a minimal delta-v (change in velocity) requirement for docking. Once the optimal orbital configuration is achieved, ISRO can proceed with the docking experiment... This is a significant milestone in India's space technology development.

For perspective old times may remember - (Using google to make sure dates etc are correct):
Gemini 8 (1966): During the Gemini 8 mission, astronauts Neil Armstrong and David Scott experienced a stuck-on thruster, causing their spacecraft to spin wildly out of control. Although they managed to regain control, the docking maneuver with the Agena target vehicle was aborted.
... similar events have happened with others .. even recent:
-- China's Tiantan-1 (2020): space station module experienced a docking failure with the Tianzhou-2 cargo spacecraft due to a navigation system error. .. satellite docking remains complex.
(By all accounts, SPADEX satellite docking experiment is a significant milestone)

[RCase]

To add/clarify/summarize the above ...(Hope this helps)

ISRO's SPADEX satellite docking experiment, initially planned for January, may be delayed until March due to orbital constraints. The experiment involves docking two satellites, SPADEX-1 and SPADEX-2, in a low Earth orbit (LEO). However, the current orbital positions of the satellites are not favorable for docking, and ISRO is waiting for a suitable window to perform the experiment. (Technically delay no big deal)

Why is the suitable window of opportunity so far out (March)? If this were a manned mission or to supply a space station, wouldn't it be appropriate to get the docking done as fast as possible?

SpaceX has been sending cargo ships to dock with the International Space Station and make it seem routine. The Russians too have been docking their cargo ships with the ISS for quite a few years. Is it easier to get the docking done because there are humans in the ISS who can help with the maneuvering of the cargo ship?

[Ashokk]

Isro's SpaDeX satellites have fuel for docking, but not enough sunlight

The Indian Space Research Organisation (Isro) is currently facing challenges with its SpaDeX satellite mission, which has enough fuel for docking but will be hindered by insufficient sunlight in the coming days as the docking window begins to shorten.

Isro Chairman V. Narayanan has, however, reassured stating, "We are not in any hurry. We will complete the mission successfully and we are moving forward with caution. No problem with being late; satellites have enough fuel."

The Chaser satellite (SDX01) has approximately 4.5 kg of propellant remaining, sufficient for two docking and undocking manoeuvres.
However, the operational window for these manoeuvres is limited. The opportunity to dock will close on January 20 and will not reopen until March 25, leaving a gap of 65 days.

The delay in docking attempts is primarily due to the spacecraft's current position relative to sunlight exposure. The lack of adequate sunlight affects the solar panels' ability to generate the power necessary for operations.

As explained by former Isro scientist Manish Purohit, the Earth’s rotation shifts the spacecraft's footprint after each orbit, complicating tracking efforts.

With the satellites travelling at approximately 7 km/s, they complete an orbit in about 90 minutes, resulting in a limited time window for ground stations to maintain contact — typically just 15-20 minutes.

[Amber G.]

To add/clarify/summarize the above ...(Hope this helps)

ISRO's SPADEX satellite docking experiment, initially planned for January, may be delayed until March due to orbital constraints. The experiment involves docking two satellites, SPADEX-1 and SPADEX-2, in a low Earth orbit (LEO). However, the current orbital positions of the satellites are not favorable for docking, and ISRO is waiting for a suitable window to perform the experiment. (Technically delay no big deal)

Why is the suitable window of opportunity so far out (March)? If this were a manned mission or to supply a space station, wouldn't it be appropriate to get the docking done as fast as possible?

SpaceX has been sending cargo ships to dock with the International Space Station and make it seem routine. The Russians too have been docking their cargo ships with the ISS for quite a few years. Is it easier to get the docking done because there are humans in the ISS who can help with the maneuvering of the cargo ship?

Good question. As a physicist, I'll provide some general insights, though I don't have the exact details. Perhaps someone can offer more information from official sources or news articles. Based on my knowledge, here are some key points:

Comparison with ISS Docking Missions:
- SpaceX and Roscosmos have developed mature systems for ISS resupply, making these operations routine. The ISS maintains a stable orbit (relatively speaking), and docking procedures have been fine-tuned over decades. Automated docking systems, are robust and can operate autonomously, though crew presence on the ISS adds a layer of safety and contingency.

Human Presence is also a factor - While human assistance isn't strictly necessary for docking, having astronauts on the ISS allows for manual override and visual monitoring.

ISS resupply missions are operational, supporting a crewed station with a fixed schedule. SPADEX, by contrast, is a research and development mission,. This flexibility allows ISRO to prioritize mission success over speed. Not to mention energy cost (fuel -economy) is BIG priority.

Orbital Mechanics/ Constraints IMHO:

Windows: Docking two satellites in low Earth orbit (LEO) requires precise alignment of their orbits -- matching their altitude, inclination, and phase. (Unlike a space station like the ISS, which maintains a stable and predictable orbit, experimental satellites like SPADEX-1 and SPADEX-2 may have more limited orbital adjustments due to fuel constraints or operational design.) Finding a window might take weeks or even months. (No big deal) (see previous post by Ashokk - about fuel and solar panels)
- Delta-V Requirements: Complex maneuvers to synchronize the velocities of the two satellites, requiring small but precise adjustments (delta-V). Not *at all unusual* for ISRO to wait for natural orbital dynamics to reduce the energy (fuel) cost of these maneuvers..

Orbital Precession: Orbits in LEO are influenced by Earth's equatorial bulge, causing them to precess over time.

Demonstration vs. Operational Mission: Unlike manned missions or cargo resupply to the ISS, which have stringent timelines due to human needs or station operations, SPADEX is a technology demonstration. There is no immediate urgency, so ISRO can afford to wait for the optimal conditions to maximize the chances of success.

Keep in mind - SPADEX involves autonomous docking, a relatively new capability for ISRO. Extensive pre-mission testing, simulations, and software validation may be also be tested/validated/perfected.
Not to forget - ground-based support, such as tracking, telemetry, and command facilities, is also being validated. (See above post - 10-15 minutes window in each orbit )

[Najunamar]

Successfully docked!,,

[SSridhar]

https://x.com/isro/status/1879749119759311078: (10:04 AM Jan. 16, 2025)

SpaDeX Docking Update:

Docking Success

Spacecraft docking successfully completed! A historic moment.

Let’s walk through the SpaDeX docking process:

Manoeuvre from 15m to 3m hold point completed. Docking initiated with precision, leading to successful spacecraft capture. Retraction completed smoothly, followed by rigidisation for stability. Docking successfully completed.

India became the 4th country to achieve successful Space Docking.

Congratulations to the entire team! Congratulations to India!

[Amber G.]

NICE!
Echoing PM Modi (Twitter):

Congratulations to our scientists at @isro and the entire space fraternity for the successful demonstration of space docking of satellites. It is a significant stepping stone for India’s ambitious space missions in the years to come.

[Supratik]

Congrats

[drnayar]

So what happens now , ISRO could potentially repeat the same test after undocking till the satellite runs out of fuel ?

[chetak]

[Cyrano]

Awesome ISRO!

[sanjaykumar]

I did not think it would happen. Success is the sweeter coming after tribulation.

Well done dudes.

[Ashokk]

https://x.com/s2a_systems/status/1879934998398267400

Finally good weather again: SpaDeX A & B on 2025-01-16 at 16:18:53 UTC over Australia. Estimated distance between the two spacecraft: ~0 m .

Congratulations to ISRO's SpaDeX team for the successful docking!

Although we missed the docking due to weather conditions in the end, we hope we were able to contribute to visualizing this exciting process.

We would like to thank you for all the motivating and engaging feedback and comments here on X. It's really a great space community here.

[Amber G.]

xpost: (Meanwhile):
Elon Musk hosts India Global Forum Business Delegation at SpaceX's Starbase facility in Texas.

[Ashokk]

Docking Video from ISRO: https://x.com/isro/status/1880277647391137947

[Amber G.]

Echoing our PM Modi:

Meanwhile India's first private satellite constellation by PixxelVSpace showcases the exceptional talent of India's youth and highlights the expanding capabilities of our private sector in the space industry

.
<video>All three Fireflies are in orbit, ready to beam back a clearer, sharper view of our planet

[SSridhar]

Do the Fireflies triplets function like the Chinese Yaogan triplets for surveillance & triangulation purposes?

[Amber G.]

Do the Fireflies triplets function like the Chinese Yaogan triplets for surveillance & triangulation purposes?

SSridharji -
From what I know (willing to be corrected if there is more info) - The Yaogan satellites are known to be used for reconnaissance and surveillance, utilizing a triplet formation to enhance their capabilities. However, the primary mission objective of the Fireflies triplets, as stated by Pixxel, is to provide global Earth imaging and hyperspectral analysis for various applications, such as agriculture, environmental monitoring, and disaster response.

So without further details (from Pixxel) my take is: Fireflies triplets do not have any secondary surveillance or triangulation capabilities...

[SSridhar]

Thank you Amber ji.