SpaDeX: ISRO brings satellites within 3 metres in trial attempt
ISRO's maiden experiment of docking two satellites in space (450 km above earth) is inching closer to success with the Target and the Chaser satellites coming as close as three meters from each other following which they have been moved back to safe distances (20 km) again.
“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,” ISRO said in a post on X on Sunday.
SpaDeX Docking Update:
SpaDeX satellites holding position at 15m, capturing stunning photos and videos of each other! 🛰️🛰️
#SPADEX #ISRO pic.twitter.com/RICiEVP6qB
— ISRO (@isro) January 12, 2025
The Space Docking Experiment (SpaDeX) project has missed two announced schedules for docking experiments on January 7 and January 9.
The two satellites were originally supposed to dock on January 7. The experiment was deferred to January 9 after ISRO scientists felt that the process required further validation through ground simulations in view of an abort scenario identified by them.
A day ahead of the docking planned on January 9, the space agency initiated the drift on the Chaser spacecraft to move closer from 500 meter to 225 meter of the Target spacecraft.
But shortly after, ISRO announced another postponement of docking. It said while making a maneuver to reach 225 m between satellites, the drift was found to be more than expected, post non-visibility period.
On January 10, ISRO announced that the drift has been arrested and spacecrafts put in a slow drift course to move closer to each other. Since then the docking process has been making a steady progress.
ISRO launched the mission on December 30.
The PSLV C60 rocket, carrying two small satellites -- SDX01 (Chaser) and SDX02 (Target) -- along with 24 payloads, lifted off from the Satish Dhawan Space Centre in Sriharikota. About 15 minutes later, the two small spacecraft weighing about 220 kilogrammes each were launched into a 475-kilometre circular orbit, as intended.
The SpaDeX project is a cost-effective technology demonstrator mission for the demonstration of in-space docking using small spacecraft, according to ISRO.
A successful demonstration of SpaDeX will make India the fourth nation to master the complex technologies that are crucial for its future missions, such as the Bharatiya Antariksh Station and landing an astronaut on the moon.
In-space docking technology is essential when multiple rocket launches are required to achieve common mission objectives.
After successful docking, electrical power transfer between the two satellites will be demonstrated which will be followed by 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.
Chaser will work as surveillance satellite. 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 (Target), developed by SAC/ISRO. The imaging will be used for natural resource monitoring and vegetation studies.
A Radiation Monitor (RadMon) payload is also mounted in SDX02, which will measure radiation dose encountered in space.