ISRO's Rendezvous, Space docking and Berthing Experiment

[FalconSlayers]

View: https://x.com/sdhrthmp/status/1847179739774988317

 

[Indx TechStyle]

Moved post above from main thread to create this one.
It sucks that I have been too occupied with life for an year now and have not been able to update the sections.
Kicking off long the pending threads.

View: https://x.com/ISROSpaceflight/status/1575842366027862016

View: https://x.com/ISROSpaceflight/status/1575842375330541569

View: https://x.com/ISROSpaceflight/status/1575842382016544768

 

[Indx TechStyle]

• Summarizing as acquisition of capability of connecting two in orbit spacecrafts temporarily or permanently.
• Essential tech for making a modular space station like MIR, ISS and Tiangong.

Quoted Ohsin from her Reddit.
Proposed Rendezvous and Docking Experiment.

From Outcome budget 2013-14^PDF

Overview of Twelfth Five Year Plan 2012-2017
. . .
4.13 In order to demonstrate emerging new technology developments, a series of experimental satellites have been planned. One of the major missions being the technology demonstration related to Docking and Rendezvous. These satellites will be flown on the PSLV missions as auxiliary or co- passenger satellites

Also from abstract of paper submitted at International Astronautical Federation.

All credits to Ohsin from NSF.

ISRO is planning an on-orbit Rendezvous Docking experiment in the near future, to develop and demonstrate the technology needed for rendezvous docking. In this experiment, two IMS(Indian Micro Satellite) Spacecrafts, one designated as target and the other designated as chaser, are launched by a PSLV launcher into two slightly different orbits. No communication link between the target and chaser during the far range rendezvous phase in which relative separation is around 50km to 5km range is envisaged and this phase is a ground guided phase. In the docking phase of the mission, docking sensors such as Laser Range Finder during the relative separation of 5 km to 0.25km, Docking Camera during the relative separation of 300m to 1m ,Visual Camera for real time imaging during the relative separation of 1m to docking are used respectively.

Source
And then I stumbled onto this MITAA newsletterPDF with a feature on Dr K Sivan. It also mentions a paper co authored by him titled "Performance Evaluation of a Vision Sensor in 3D Virtual Environment for Rendezvous and Docking Application"
Full(PDF): http://ieeexplore.ieee.org.sci-hub.org/xpl/articleDetails.jsp?tp=&arnumber=6461671
Wonder when this will happen..
Edit(18 Feb 2016 ):
In UIM 2015 Dr. M. Annadurai mentioned future Rendezvous & Docking Mission / Formation Flying using Microsats


View: https://youtu.be/aC1RPMUeyWw?si=9CdW2bVH7hTa0ZLN

Above snippet was extracted from http://livestream.nrsc.gov.in/plenary.html 46 min onward.
Also mentioned in video "A Journey from ARYABHATA to ASTROSAT" @ 12m5s.
http://www.isac.gov.in/media/A2A.webm
Edit (26 Feb 2016):
Official name is SpaDEx (Space Docking Experiment)
https://in.linkedin.com/in/ravikumar-lagisetty-3214b615

 

[Indx TechStyle]

Copied Antariksh Blogspot. Not using quotes for easier readability (no COPYVIO intended).

Wednesday, July 31, 2013
ISRO Rendezvous & Docking experiment Update
As mentioned previously on this blog, ISRO has been working on a rendezvous and docking (RVD) experiment mission involving two IMS (Indian Micro Satellite) series spacecrafts. ISAC, a ISRO centre, has been involved in developing navigation and guidance algorithm for RVD. In this experiment, two IMS Spacecrafts, one designated as target and the other designated as chaser, will be launched by a PSLV launcher into two slightly different orbits. There will be no communication link between the target and chaser during the far range rendezvous phase in which relative separation between the spacecrafts will be around 50km to 5km range and this phase will be a ground guided phase. In the docking phase of the mission, docking sensors such as Laser Range Finder during the relative separation of 5 km to 0.25km, Docking Camera during the relative separation of 300m to 1m ,Visual Camera for real time imaging during the relative separation of 1m to docking will be used respectively.

For the purpose of testing and verification of vision based docking algorithms before a real world implementation is carried out, ISRO has developed a 3D simulation environment that is being used to simulate docking phase of the mission. A snap of the simulation is presented in the Figure below.

[td][/td] [td]3D Simulation of Chaser and Target to test vision based RVD. (credit ISRO, [1])[/td]

​

Targeted Applications of RVD: RVD technology is one of many enabling technologies for ISRO's human space flight program. Another promising application of this technology will be increasing age of ISRO's satellites like that from IRS, INSAT and IRNSS systems. RVD technology will allow a resupply (fuel, power pack etc) spacecraft to dock with a satellite in orbit and allow for replenishment of fuel and power pack, thereby increasing satellites age. To facilitate this, as per my research, ISRO has been designing its newest satellite bus called I-6K, which is a unified bus with modular design ,multi EV panels and scalable structure (Bus module & payload module). A modular design will allow easy and fast replacement of bus module in the orbit by the resupply space craft. The resupply spacecraft might itself be a new bus module (with fuel, power pack etc.) that will dock with the payload module in the orbit after the old bus module undocks.



[1] Gladwin J, et al., Performance Evaluation of a Vision Sensor in 3D Virtual Environment for Rendezvous and Docking Application.

 

[Indx TechStyle]

Reference budget from older Lok Sabha Query.

 

[Indx TechStyle]

 

[Indx TechStyle]

@haldilal I am taking liberty to move SPADEX related posts here if you don't mind.

 

[Aaj Ka Hero]

View: https://x.com/Rethik_D/status/1849720610814824557

 

[Indx TechStyle]

ISRO gearing up for space docking mission by December end: Somanath​

 

[fire starter]

View: https://x.com/ISROSpaceflight/status/1869699504418554292?t=0hmSW38wO9YcuUAQw5OypQ&s=19

 

[Anonymous Bharata]

View: https://x.com/isro/status/1870407942060527960

 

[fire starter]

View: https://x.com/BhatShricharan/status/1870439921007415592?t=PZBbrCWOp_Y970xY-Kk1Qw&s=19

 

[Indx TechStyle]

SPADEX from ISRO page, link embedded.
Copyright: SRO
SpaDeX Mission
December 21, 2024

SpaDeX mission is a cost-effective technology demonstrator mission for the demonstration of in-space docking using two small spacecraft launched by PSLV. This technology is essential for India’s space ambitions such as Indian on Moon, sample return from the Moon, the building and operation of Bharatiya Antariksh Station (BAS), etc. In-space docking technology is essential when multiple rocket launches are required to achieve common mission objectives. Through this mission, India is marching towards becoming the fourth country in the world to have space docking technology.
Objectives:

The primary objective of the SpaDeX mission is to develop and demonstrate the technology needed for rendezvous, docking, and undocking of two small spacecraft (SDX01, which is the Chaser, and SDX02, the Target, nominally) in a low-Earth circular orbit. Secondary objectives include:

• Demonstration of the transfer of electric power between the docked spacecraft, which is essential for future applications such as in-space robotics,
• Composite spacecraft control, and
• Payload operations after undocking.

Mission Concept:

The SpaDeX mission consists of two small spacecraft (about 220 kg each) to be launched by PSLV-C60, independently and simultaneously, into a 470 km circular orbit at 55° inclination, with a local time cycle of about 66 days. The demonstrated precision of the PSLV vehicle will be utilized to give a small relative velocity between the Target and Chaser spacecraft at the time of separation from the launch vehicle. This incremental velocity will allow the Target spacecraft to build a 10-20 km inter-satellite separation with respect to the Chaser within a day. At this point, the relative velocity between the Target will be compensated using the propulsion system of the Target spacecraft.

At the end of this drift arrest maneuver, the Target and Chaser will be in the same orbit with identical velocity but separated by about 20 km, known as Far Rendezvous. With a similar strategy of introducing and then compensating for a small relative velocity between the two spacecraft, the Chaser will approach the Target with progressively reduced inter-satellite distances of 5 km, 1.5 km, 500 m, 225 m, 15 m, and 3 m, ultimately leading to the docking of the two spacecraft. After successful docking and rigidization, electrical power transfer between the two satellites will be demonstrated before undocking and separation of the two satellites to start the operation of their respective payloads for the expected mission life of up to two years.
New Technologies:

The indigenous technologies developed for enabling this docking mission are as follows:

• Docking mechanism,
• A suite of four rendezvous and docking sensors,
• Power transfer technology,
• Indigenous novel autonomous rendezvous and docking strategy,
• Inter-satellite communication link (ISL) for autonomous communication between spacecraft, incorporated with inbuilt intelligence to know the states of the other spacecraft,
• GNSS-based Novel Relative Orbit Determination and Propagation (RODP) processor to determine the relative position and velocity of the other spacecraft,
• Simulation test beds for both hardware and software design validation and testing.

In addition, SpaDeX, because of its small size and mass, is even more challenging due to the finer precision required for the rendezvous and docking maneuvers compared to docking two large spacecraft. This mission will be a forerunner for autonomous docking needed for future lunar missions like Chandrayaan-4 without the support of GNSS from Earth.
Docking Mechanism:

The docking mechanism is a low-impact docking system (approach velocity is in the order of 10 mm/s), androgynous (docking systems are identical for both spacecraft, Chaser & Target), and is a peripheral docking system (concept similar to the International Docking System Standard used by other agencies for human missions). The mechanism is smaller (450 mm) with one degree of freedom for extension and uses two motors compared to the IDSS (800 mm) on a hexapod with 24 motors. Multiple test beds were established to test the hardware and software simulation of the docking kinematics to verify and finalise the docking approach parameters.
Sensor Suite:

The additional sensor suite in this mission includes Laser Range Finder (LRF) and Corner Cube Retro Reflectors to work for a range of 6000 to 200 m for determining range (R). The set of Rendezvous Sensors (RS) is used in the range of 2000 to 250 m and from 250-10 m. RS provides the relative position (x, y, z) while LRF determines both relative position and velocity independently.

Proximity and Docking Sensor (PDS) provides relative position and velocity over a range of 30 m to 0.4 m. Laser Diodes (LDs) are used as targets for RS & PDS. A video monitor is used in the 20 to 0.5 m range and it will capture the video of the docking event. A Mechanism Entry Sensor (MES) is used from 8 cm to 4 cm to detect chaser entry into the target spacecraft during docking. Multiple test beds were used to calibrate and validate these sensors before accepting them for the mission.
ISL-Enabled GNSS-Based RODP:

Like all ISRO satellites in low-Earth orbit, both the SpaDeX spacecraft carry a differential GNSS-based Satellite Positioning System (SPS), which provides PNT (Position, Navigation, and Timing) solutions for the satellites. In SpaDeX, a novel RODP processor is included in the SPS receiver, which allows accurate determination of the relative position and velocity of the Chaser and the Target. By subtracting the carrier phase measurements from the same GNSS satellites in both Chaser and Target SPS receivers, highly accurate relative states of the two satellites are determined. The VHF/UHF transceivers in both satellites aid this process by transferring the GNSS satellite measurements from one satellite to the other. Hardware and software test beds, including closed-loop verifications, were carried out to characterise the RODP performance.
Rendezvous and Docking Algorithms:

Up to an inter-satellite distance (ISD) of 5 km, standard orbit maintenance and attitude control algorithms employed in ISRO LEO spacecraft are used. As the spacecraft are in circular orbit, and any addition or reduction of velocity to the satellites will result in orbit change, the V-bar strategy using n-Pulse, Glideslope and PV guidance algorithms are employed to reduce the ISD between the satellites, hold at fixed ISDs to evaluate the sensors and software, and finally docking. These algorithms were converted into software for achieving the rendezvous and docking. These software solutions were tested and validated in multiple digital, hardware-in-loop, onboard-in-loop, software-in-loop, and robotic simulations.
Post-Docking Activities:

After the docking and undocking events, the spacecrafts will be separated and used for application missions.

• A High-Resolution Camera (HRC) with a 4.5 m IGFOV and a swath of 9.2 x 9.2 km (snapshot mode) and 9.2 x 4.6 km (video mode) from a 450 km altitude is mounted in SDX01. This is a miniature version of the surveillance camera developed by SAC/ISRO.
• A Miniature Multi-Spectral Payload (MMX) is mounted in SDX02, developed by SAC/ISRO. This has four VNIR bands (B1/B2/B3/B4) at 450 nm to 860 nm and a 25 m IGFOV with a swath of 100 km from a 450 km altitude. The imaging is useful for natural resource monitoring and vegetation studies.
• A Radiation Monitor (RadMon) payload is mounted in SDX02, which will measure radiation dose encountered in space. This will help in generation of a radiation database for future Total Ionization Dosimeter (TID) and Single Event Upset (SEU) measurements for space science studies, with applications in human spaceflight.

Spacecraft Development:

The SpaDeX spacecraft were designed and realized by the UR Rao Satellite Centre (URSC) with the support of other ISRO centers (VSSC, LPSC, SAC, IISU, and LEOS). The spacecraft, in its orbital phase, will be controlled from ISTRAC using ISRO ground stations and other externally hired ground stations. The full integration and testing of the satellite were carried out at M/s Ananth Technologies, Bangalore, under the supervision of URSC. Presently, after completing all tests and clearances, the spacecraft has moved from URSC to SDSC and is undergoing preparations for launch.

 

[Indx TechStyle]

We are seeing a different looking payload fairing on an Indian rocket for first time in past few decades (next one will be towered fairing of HLVM3).

 

[Anants]

We are seeing a different looking payload fairing on an Indian rocket for first time in past few decades (next one will be towered fairing of HLVM3).
View attachment 19209
View attachment 19210

For a moment I thought It was interstage dome. Did not realise it was last stage payload faring. Very unique. I doubt we have seen similar fairing design elsewhere in world?

 

[Indx TechStyle]

For a moment I thought It was interstage dome. Did not realise it was last stage payload faring. Very unique. I doubt we have seen similar fairing design elsewhere in world?

Don't think like this one but there are plenty of othet unique or surreal payload fairings around world.

 

[Anonymous Bharata]

We are seeing a different looking payload fairing on an Indian rocket for first time in past few decades (next one will be towered fairing of HLVM3).
View attachment 19209
View attachment 19210

Its not payload fairing, it's just a temporary cap, to avoid the exposure of PS4 stage to outside environment as PSLV is transported from PIF to FLP.

Integration of Satellite happens on FLP, not in PIF