SPaDEx Chaser, SPaDEx Target, POEM-4 – PSLV-C60 CA – Шрихарикота FLP – 30.12.2024 16:30 UTC

[zandr]

ISRO  @isro  ·  3h
SpaDeX Docking Update:

SpaDeX satellites holding position at 15m, capturing stunning photos and videos of each other!

Зависание на 15 м. Фото, видео.

[zandr]

https://x.com/isro/status/1878254580825497776

ISRO  @isro  ·  2h
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.

После сближения 3 м, разошлись. Анализируют.

[zandr]

Код Выделить Развернуть

https://www.youtube.com/watch?v=dVg64bXlCDg

https://www.youtube.com/watch?v=dVg64bXlCDg 1:10
SpaDeX in Space Docking satellites holding position at 15m
  Moter World

[zandr]

https://x.com/s2a_systems/status/1878347299081814464

s2a systems  @s2a_systems
The latest SpaDeX image from South America. The distance between the two satellites on 2025-01-12 at 07:26:17 UTC was about 4.3 km. So the satellites are back at safe distance, as stated by ISRO in their recent post:

Разошлись на 4,3 км.

[zandr]

s2a systems  @s2a_systems  ·  Jan 12
SpaDeX A & B on 2025-01-12, 18:27:02 UTC over Australia. Estimated distance between the two spacecraft near max elevation: ~10.9 km.

После расхождения на 11 км, начался новый этап сближения:
https://x.com/s2a_systems/status/1878867969813696816

s2a systems  @s2a_systems
SpaDeX A & SpaDeX B on 2025-01-13, 17:55:56 UTC during this evening's high elevation pass over Australia. Estimated distance between the two spacecraft near max elevation: ~1.6 km.

[zandr]

https://x.com/s2a_systems/status/1879106404973437252

s2a systems  @s2a_systems
The last SpaDeX update from South America for today. Estimated distance between the two spacecraft: ~1.5 km. Recorded at 2025-01-14, 09:38:47 UTC.

Держат дистанцию.

[zandr]

https://x.com/s2a_systems/status/1879337210681700826

s2a systems  @s2a_systems
SpaDeX low elevation pass over South America. The estimated distance between the two spacecraft is approximately 1.2 km. Recorded on 2025-01-15 at 00:53:35 UTC

Чуть ближе.
ISRO молчит.

[zandr]

s2a systems  @s2a_systems
SpaDeX A & B over South America on 2025-01-15 at 07:31:29 UTC. Estimated distance between the two spacecraft: ~900m.

[cross-track]

Эта музыка будет вечной
Если я заменю батарейки
Эта музыка будет, будет вечной
Эта музыка будет вечной
Если я заменю батарейки
Если я заменю батарейки (с)

[zandr]

https://x.com/iamkrishradha/status/1879072117196734790

Radha Krishna Kavuluru  @iamkrishradha
There has been some news for SPADEX docking "Window" closing in next few days. It was mentioned that SPADEX will no more be visible from ground stationsl This is wrong.
There are 2 main reasons , for this window and here are they breifly.
1) Power generated by solar panels in inclined orbit.
2) Continuous visibility for entire docking sequence.

Want to know more? Read on. (1/n) 
ps : all the analysis done by myself with opensource tracking data. Nothing official.

Спойлер

Okay so before going to actual reasons, let me show you RF Visibility of SPADEX over India. This is a direct indication of the news published in media being wrong.

Next going to power
(2/n)

Satellites are usually powered by Solar panels. The energy depends on the illuminated area ( depends on area of solar panels ) and illuminated time.

But here comes the tricky part. The earth hides sun for a certain period of orbit for every LEO Satellite ( imagine the satellite is in the night part of earth ).

For a usual Sun synchronous orbit , this period is mostly constant with every orbit taking 1.5 hour and eclipse time ( sun hidiing time ) being ~32 minutes

There is a very slight variation because of RAAN shifting , but we can neglect it for now.

Day / Night / Day / Night and the cycle continues. For example here is the total eclipse time per day ( for one year ) for RESOURCESAT-2 ( Sun sync. orbit ) - ISRO'S satellite.
(3/n)

But for inclined satellites , Like SPADEX/ISS , this eclipse time is not constant. Infact, this is the major benefit of inclination. There are certain times of the year where you can almost be lit by sun and certain times of the year when you're mostly in eclipse.

So here is a simulated Eclipse time per day for SPADEX
for the entire year. See the first valley??

That's saying SPADEX will have eclipse for only 30 minutes of day.

One week from today ( JAN 20 ) the eclipse time will go to 200 + minutes and then exponentially go to 500 minutes.

So this is the constraint. The next valley is only in MARCH. That too a very narrow one.

The conditions similar to the first window is only attainable again in JUNE ending.
(4/n)

Here is one week eclipse graph for on-going window.
Now yes sure, Resourcesat-2 operates with 400 minutes eclipse why can't spadex?

Well it depends on what the satellite is supposed to do.
Resourcesat-2 has to point nadir and turn on ccd for th day lit time. That's it ( other than health keeping )

But spadex, is all about so many subsystems and control system and "DOCKING"

+ The power storage ( batteries ) on both spacecraft may be entirely different.

My GUT feeling is that, ISRO planned the entire mission to be finished in this window and did not envision functioning in eclipses. ( as we will for sure have another window ) and saved on battery/mass in EPS.

This may be a mission constraint. Something that was planned for. So yeah , this is the window is what i can gather. 

+ There may also be a requirement for continuous visibility for entire docking sequence ( which will depend on the antennas they are having in hand , which i have no idea about , so can't model it ). But for sure we have many >25 degree passes and many >60 degree passes also.

So a major window constraint might be with power.

PS : All analysis personal and not  reviewed. May have mistakes. Deal with caution
(END)

[свернуть]

(иллюстрации пропущены)
Есть мнение (частное), что благоприятное окно закрылось, и надо ждать следующее.

[Rocinante]

https://x.com/ISROSpaceflight/status/1879736371889283363

ISRO has successfully docked 2 spacecrafts in Earth orbit for the first time!! 🛰🤝

This makes India the 4th nation to indigenously develop docking technology & it's also a crucial milestone for ISRO's future missions

https://x.com/isro/status/1879754403306967291

Post docking, control of two satellites as a single object is successful.

Undocking and power transfer checks to follow in coming days

https://x.com/indianspacepost/status/1879763063223795735

Successful SPADEX docking is the biggest thing happened to ISRO since Chandrayaan-3 and Aditya-L1.

Power transfer and cross attitude control demonstration yet to follow, but this is already a massive feat.

[спец]

Шутка из фейсбука.
Вы не можете просматривать это вложение.

[zandr]

https://x.com/isro/status/1879749119759311078

ISRO  @isro  ·  12h
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!

Без картинок (

[zandr]

Код Выделить Развернуть

https://www.youtube.com/watch?v=9REPYHXjBIo

https://www.youtube.com/watch?v=9REPYHXjBIo
SPADEX EVENT VIDEO
  ISRO Official
ISRO successfully completed docking of two SPADEX satellites (SDX-01 & SDX-02) in the early hours of 16 January, 2025.

Долгожданное видео
и экран подтверждения стыковки (все аплодируют)

Вы не можете просматривать это вложение.

[zandr]

https://timesofindia.indiatimes.com/science/isro-preps-for-more-docking-trials-with-same-spadex-sats-to-perfect-precision-in-space/amp_articleshow/117378839.cms

Isro preps for more docking trials with same SpaDeX sats to perfect precision in Space
^{Chethan Kumar | TNN | Jan 20, 2025, 08:48 IST}
BENGALURU: The Indian Space Research Organisation (Isro) is preparing for additional docking attempts with its recently (Jan 16) linked satellites, focusing on achieving greater precision in its automated docking capabilities.
M Sankaran, director of the UR Rao Satellite Centre (URSC), which spearheaded the Space Docking Experiment (SpaDeX) told TOI exclusively that the space agency is conducting detailed assessments of the docking accuracy before proceeding with the next phase of experiments.
"We have to gain more information about how accurately we have achieved this docking and how much more accuracy we can achieve," Sankaran said, emphasising that the actual act of docking is just one aspect of the mission.
"How accurately we are docking is important. We will make an assessment of how accurately we have docked and how much we can improve," he said.

Small separations
Isro, which launched the SpaDeX mission on Dec 30, with two 220kg satellites put in space as separate units, had achieved a peak a inter-satellite distance of 12.8km before initiating a series of mamanoeuvres that eventually culminated in the Jan 16 docking.
Isro employed a petal-based docking system, aligned with international standards including the International Docking System Standard (IDSS).
On whether the fuel remaining on the satellites were sufficient to carry out more docking attempts, Sankaran said that for the upcoming trials, Isro plans to separate the satellites by shorter distances, potentially not exceeding 100 metres, unlike the initial approach.
"Fuel consumption won't be a constraint for these experiments, as the focus will be on perfecting the final approach and docking mechanism rather than long-range maneuvers," Sankaran said.

Sensors & Sat Capture
The success of these operations relies on a sophisticated array of five different types of sensors, each activated at specific ranges. These sensors, which were evaluated at each step in the run-up to Isro's first successful attempt on Jan 16, are crucial to both the rendezvous and the eventual docking.
The Proximity and Docking Sensor (PDS) becomes operational from 20 meters, while other sensors work at varying distances – some at long range, others at 200 meters, and some specifically for close proximity operations.
The final phase of docking involves specialised mechanism entry sensors that detect when one satellite's petals enter the other satellite's mechanism.
"...After it enters, we have to trigger mechanisms to grab the satellite. Once it is entered, it should get trapped there. It should not go out," Sankaran explained.
Currently, Isro's team is analysing data from the successful docking and running simulations to prepare for the next attempt. While the exact timeline for satellite separation remains under review, Sankaran indicated it would take "a few days" as they carefully evaluate their options.

Mastery & future missions
The decision to activate the satellites' payloads between docking attempts remains flexible.
"If we can do what we want to do immediately, we will do those things and then turn on the payload later. If that is going to take time, then we will turn on the payload and go ahead with the other observations. When we are ready, we will do the docking experiment again," he added.
As reported by TOI, the successful docking achieved by Isro was the first step towards mastering the technology, which will have to be done multiple times in different configurations, before Isro could confidently use it for future missions like Chandrayaan-4 and India's own space station.
And, the planned additional trials will help Isro decide how future docking experiments are designed. For Chandrayaan-4, which requires docking to bring back samples, Isro will be operating spacecraft of different sizes, while docking for the space station would have different challenges.

Планируют развести на 100 метров и повторить стыковку.

[zandr]

Однако
https://x.com/s2a_systems/status/1891496114248892886

s2a systems  @s2a_systems
It's been some time since the last SpaDeX post - so here we go: SpaDeX A & B, still docked, during today's morning pass over South America, 2025-02-17 10:02:13 UTC.

до сих пор состыкованы.

[zandr]

https://x.com/s2a_systems/status/1900266474180170136

s2a systems  @s2a_systems
SpaDeX A & B (after successful undocking), during a low elevation pass over Australia, today 2025-03-13 at 19:03:44 UTC. Thx for the heads-up
@this_is_tckb

Разошлись.

[zandr]

Код Выделить Развернуть

https://www.youtube.com/watch?v=m0BTq12Ypr4

https://www.youtube.com/watch?v=m0BTq12Ypr4 4:54
ISRO SpaDex Mission's De-Docking Complete Footage #isro
  thebhp
ISRO Successfully Completes SpaDex Mission's De-Docking, Paving Way For Future Space Endeavors.
On Thursday, ISRO announced the successful completion of the SpaDex Mission's de-docking.
The undocking process involved a precise sequence of events, culminating in the separation of the SDX-01 (Chaser) and SDX-02 (Target) satellites that was launched on December 30 in 2024, using Polar Satellite Launch Vehicle (PSLV)-C60, from the Satish Dhawan Space Centre in Sriharikota. It included the successful extension of SDX-2, the planned release of Capture Lever 3, and the disengagement of the Capture Lever in SDX-2.
After these maneuvers, the decapture command was issued in both SDX-1 and SDX-2, leading to the successful separation of the satellites. ISRO successfully completed docking of the two SPADEX satellites (SDX-01 and SDX-02) in the early hours of January 16 this year, marking India's entry towards becoming the fourth country -alongside China, Russia and the United States-in the world to have space docking technology.

[zandr]

https://x.com/isro/status/1900077225476767766

ISRO  @isro
Spadex Undocking Successful!
Key sequence of events:

- SDX-2 extension successful
- Capture Lever 3 released as planned
- Capture Lever in SDX-2 disengaged
- Decapture command issued in SDX-1 & SDX-2

FINALLY, SUCCESSFUL UNDOCKING!
Congratulations, Team ISRO!