On December 30 at 16:30 UTC, from the second launch pad of the Satish Dhawan Space Center on the island of Sriharikota in India, ISRO launched a PSLV-CA (Polar Satellite Launch Vehicle—Core Alone) carrying the two vehicles of the SPADEX (Space Docking Experiment) mission.
The launch took place regularly, and after 10 minutes, the two vehicles, Chaser and Target, were deployed in LEO orbit where they will perform, on January 7, the reciprocal approach and docking maneuvers in orbit, testing the related systems.
The mission represents a fundamental step for the development of the Gagayaan pilotable vehicle, whose inaugural launch is scheduled for 2025, and for the construction of the Indian orbital base BAS (Bharatiya Antariksha Station – Indian Space Station).
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The SPADEX mission
The primary objective of the SPAce Docking EXperiment mission is to develop an Indian autonomous technology for the approach and docking in low Earth orbit of two autonomous spacecraft called SDX01 and SDX02 of about 220 kg each.
To achieve this, the two spacecraft, equipped with the IDS (International Docking System), will carry out a series of maneuvers, lasting two days, in which they will successfully repeat several times the automatic approach and docking and the transfer of energy from one vehicle to the other.
In detail, the two androgynous mechanisms are a 1:2 scale representation of the actual system (400 mm in diameter against the 800 of the real system).
The automatic approach was carried out thanks to a positioning system with laser retroreflectors and a GNSS satellite positioning system.
After the separation of the two vehicles, the mission continues with other experiments mounted on the individual spacecraft consisting of a radiation detector (RadMon) and a multispectral detector (MMX) mounted on SDX02 and a high-resolution camera (HRC) mounted on both. The fourth stage of the PSLV (PS4) once separated from the load, began its mission as an autonomous satellite equipped with a series of experimental equipment for new technologies to be tested in space including a small mobile robotic arm (RRM-TD Relocatable Robotic Manipulator) and an innovative capture arm for space debris.
Hawt 🔥🔥
— SRI SAIDATTA (@nssdatta) December 27, 2024
SpaDEx Docking Animation
pic.twitter.com/FnppQUPzat
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The PSLV vehicle
The Polar Satellite Launch Vehicle is a proven modular launch system with four stages of the medium-light class, whose first flight took place in 2007. PSLV can be used both for the launch of loads in low orbit up to 3,200 kg and loads in the GTO (Geostationary transfer orbit) up to 1,425 kg.
There are currently three versions that differ in the number of lateral solid-fuel boosters attached to the first stage: the CA (Core alone), the one used for the SPADEX mission, has no boosters, while the G and XL both have 6 but of a different type: more powerful for the XL.
The central core consists of four stages of which the first and third are solid fueled, while the second and fourth are powered by hypergolic fuel.
It is a very reliable launcher, with 18 out of 18 successful launches, and economically competitive with a cost per launch of 15 million USD.
Two other versions were planned: the more powerful HP and the light 3S but the development was interrupted for the start of the reusable launcher program NGLV (Next-generation launch vehicle)
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