This mission is an important step for ISRO as it will showcase its ability to dock two spacecraft in space.
India is gearing up for a major milestone in its space journey with the launch of the Space Docking Experiment (SpaDEX), planned for December 30, 2024. The mission will be carried out by the Indian Space Research Organisation (ISRO) using the Polar Satellite Launch Vehicle (PSLV-C60). The rocket is set to take off at 9:58 PM IST from the Satish Dhawan Space Centre in Sriharikota.
This mission is an important step for ISRO as it will showcase its ability to dock two spacecraft in space. This is a key technology for future space missions. The main goal is to design and test the systems needed for bringing two spacecraft together, docking them, and then separating them again.
Mission Summary and Goals
The SpaDEX mission will send two identical satellites into space, named Chaser (SDX01) and Target (SDX02) . Each satellite weighs about 220 kilograms .
The two satellites will be positioned in a circular orbit 470 km above Earth, at an angle of 55 degrees. The objectives of the mission are:
Showing accurate movements needed to bring the satellites close together and connect them.
Testing how electricity can be shared between two connected spacecraft.
functioning of the payload after the satellites separate, with the mission lasting up to two years.
Note : The term “payload” refers to the essential equipment or instruments carried by a spacecraft to perform its mission. It’s a critical part of the satellite, as it directly contributes to achieving the mission’s goals.
ISRO announced that the PSLV-C60 rocket has been fully assembled and moved to the First Launch Pad for final tests before the mission.
India’s Progress Toward a Space Station
The SpaDEX mission is an important step for India’s space exploration goals,” an ISRO official said. “It will make India the fourth country in the world to develop advanced docking technology.”
This technology is important for missions that need several launches to work together for a shared goal. It will be useful for tasks like repairing satellites, coordinating multiple spacecraft to fly in formation, and building complex structures in space, such as India’s planned space station, the Bharatiya Antariksh Station (BAS).
Creative Use of PSLV’s Fourth Stage : Apart from its docking goals, the mission will make use of the PSLV rocket’s used-up fourth stage, called POEM-4 (PSLV Orbital Experimental Module). Instead of letting it go to waste, this stage will be turned into a platform to carry out experiments in microgravity, helping scientists test and study various conditions in space.The mission will carry 24 payloads onboard, provided by various academic institutions and startups.
“PSLV’s Fourth Stage Transformed for Experiments”
The 4th stage of the PSLV rocket is the final part that helps place satellites into their orbits. Once its job is done, it usually becomes space junk, floating unused in orbit. However, ISRO has found a way to reuse it by turning it into a science platform called POEM. Now, instead of being wasted, it carries small experiments and tests in space, especially in microgravity. This makes better use of the rocket and reduces waste in space.
After placing satellites into their desired orbits, the PSLV’s 4th stage (PS4) remains in space with leftover fuel and onboard systems like batteries, solar panels, and communication equipment. ISRO modifies this stage to act as a platform for experiments. By attaching scientific instruments and sensors to it before launch, the stage can perform experiments in microgravity, test new technologies, or study space conditions. The fuel helps in minor adjustments, and its power systems keep the experiments running, turning the once-unused stage into a cost-effective space lab.
Mission Design and Implementation Strategy
The Chaser and Target will be released into orbit at the same time but as separate objects.
The PSLV rocket is very accurate, so it will make sure the satellites are placed in orbit with only a small difference in their speeds. This means the satellites will start off moving almost together, making it easier to control and manage their movements in space.
The Target satellite will use its onboard thrusters to slowly move away from the Chaser satellite, creating a distance of 10-20 kilometers between them. This phase is called the “Far Rendezvous” (a planned meeting or approach in space), where the satellites are far apart but still close enough to interact or prepare for the next steps in the mission.
The Chaser satellite will gradually move closer to the Target satellite in steps, reducing the distance between them to 5 kilometers, then 1.5 kilometers, then 500 meters, 225 meters, 15 meters, and finally 3 meters. At this final distance, the two satellites will connect, or “dock,” with each other. Once they are docked, the mission will test the transfer of power from one satellite to the other. After this test is complete, they will separate again to carry out other tasks with their payloads.
The Chaser satellite, is equipped with a powerful high-resolution camera. The Target satellite, is equipped with special tools to study Earth and space. It carries a multispectral sensor, which can capture detailed images in different light wavelengths. This helps monitor natural resources, track vegetation health, and study the environment. Additionally, it has a radiation monitor to measure space radiation, which will help scientists collect important data and build a database for future research.
Why SpaDEX Matters ?
The SpaDEX mission is more than just a technology test; it is an important step toward ISRO’s bigger plans. Learning how to dock spacecraft is essential for future goals like bringing back samples from the Moon, exploring other planets, and creating a long-term human presence in space.
India is working to join a small group of countries—the US, Russia, and China—that have successfully developed in-space docking technology. This mission highlights ISRO’s dedication to creating advanced space technology that is both effective and affordable.
For the first time, ISRO is sending a robotic arm into space to test how it can collect space debris. Along with this, India’s first astrobiology experiments (studies related to life in space and how living organisms survive in space conditions) created by students from RV College of Engineering in Bengaluru and Amity University in Mumbai, are also heading to space. These experiments are part of the 24 payloads that the POEM platform will carry.
Out of the 24 payloads, 14 come from ISRO’s Department of Space. One of these will focus on developing technologies to grow and sustain plants in space or on other planets. The remaining 10 payloads are from non-government organizations, including contributions from educational instit
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