- Why in news
- On 23 March 2026, in a written Rajya Sabha reply, Dr. Jitendra Singh said ISRO is studying two follow-on docking experiments, SPADEX-2 and SPADEX-3.
- What it is
- SPADEX (Space Docking Experiment) is an ISRO mission that demonstrates rendezvous, docking and undocking of two small spacecraft in orbit. India launched it in December 2024 using PSLV. Docking is needed for crewed flights, crew transfer, and moving power or propellant between spacecraft.
- SPADEX-2
- A study for docking in a highly elliptical orbit, meant to match the Chandrayaan-4 lunar sample return mission. It includes sample transfer between two modules.
- SPADEX-3
- A study for docking in circular orbit between two pressurized modules, using the Bharatiya Docking System (BDS). It is a precursor for docking at the Bharatiya Space Station.
- Why docking matters
- Rendezvous and docking technology is critical for crewed missions, for crew transfer and for propellant, fluid and power transfer.
- Link to Gaganyaan
- Validating these technologies in orbit helps docking of the Gaganyaan module to stations like the Bharatiya Antariksh Station.
- Launch vehicle
- The first SPADEX mission was launched on ISRO's PSLV in December 2024.
Don’t confuse with SPADEX vs Gaganyaan: SPADEX demonstrates docking technology with small satellites. Gaganyaan is India's crewed spaceflight programme.
Science and technology: 57 Prelims questions since 2013; most test the concept behind the news, not the news itself. In Mains, 12 news-triggered questions.
Why it matters
- Docking skill is a base for the Bharatiya Antariksh Station, crew transfer and Chandrayaan-4 sample return.
Problems
- Docking in elliptical and circular orbits needs precise relative navigation and control, and must be proven step by step.
Way forward
- Involve academic institutes and national laboratories more in payloads and algorithms.
Put in your answer
Academic involvement: Academic institutes and national laboratories contributed to Aditya-L1 through payload realization.
- 2019Mains GS3 · Q6India's plan for its own space station and its benefits to the space programme
- 2017Mains GS3 · Q7Technological and logistical obstacles to India's manned space mission, critically examined
- 2025Prelims Q83Which of the space missions Axiom-4, SpaDeX and Gaganyaan involve docking?
UPSC’s own questions that come close to this issue, from our Prelims and Mains banks.
Prelims practice · Statements
Ours, not from a UPSC paper
Consider the following statements:
- 1.SPADEX-2, now under study by ISRO, replicates docking in a highly elliptical orbit in line with the Chandrayaan-4 lunar sample return mission.
- 2.SPADEX-3, now under study by ISRO, replicates docking in a highly elliptical orbit as a precursor to docking at the Bharatiya Space Station.
- 3.The proposed circular-orbit docking mission is to use the Bharatiya Docking System (BDS) between two pressurized modules.
Which of the statements given above is/are correct?
True or false?
1 of 6
Statements the way Prelims prints them. Say first, then see the fact.
1.SPADEX-2 is being studied to replicate docking in a highly elliptical orbit, relevant to the Chandrayaan-4 lunar sample return mission.
True. SPADEX-2 targets highly elliptical orbit docking for Chandrayaan-4.
2.SPADEX-3 is proposed to replicate docking in a highly elliptical orbit as a precursor to the Bharatiya Space Station.
False. SPADEX-3 replicates docking in circular orbit.
3.The upcoming docking mission with circular orbit objectives proposes to use the Bharatiya Docking System (BDS) between two pressurized modules.
True. BDS is to be used between two pressurized modules in circular orbit.
4.Rendezvous and docking technology is useful only for crew transfer and has no role in propellant or power transfer.
False. It also enables propellant, fluid and power transfer.
5.The first SPADEX mission was launched by ISRO on a GSLV Mk III vehicle.
False. It was launched on PSLV.
6.Academic institutions take part in Indian space missions only through commercial contracts and not through research proposals funded by the Department of Space.
False. They take part through identified research proposals funded by the Department.
Written by us from the release, not by UPSC; checked by a second model.
Worth revising until Prelims 2027: most news questions come within two years of the event.