How will tests ‘SOLVE’ Gaganyaan astronauts safe landing | Explained
The Indian Space Research Organisation (ISRO) successfully conducted the first ground test of the solid motor for the Sub-Orbital Launch Vehicle for Experiments (SOLVE) on 3 July 2026 at the Satish Dhawan Space Centre, Sriharikota.
All motor performance parameters met expected values during the test.
SOLVE is a purpose-built sub-orbital test vehicle designed to validate the parachute-based deceleration system that will be used to bring Gaganyaan's crew module safely to splashdown.
The test marks a significant milestone in ISRO's systematic qualification of the Gaganyaan human spaceflight programme's re-entry and recovery chain.
Gaganyaan Programme — India's Human Spaceflight Mission
Gaganyaan is India's first crewed orbital spaceflight programme, being developed by ISRO under a mandate from the Union Government. The programme aims to demonstrate India's capability to send Indian astronauts (Gaganyatris) to low Earth orbit and return them safely. In its first crewed mission, three astronauts will orbit Earth at approximately 400 km altitude for up to seven days aboard the crew module. Four Indian Air Force pilots have been selected and trained as astronaut-candidates. The programme follows a phased approach: multiple uncrewed missions (including with a humanoid robot, Vyommitra) will precede the crewed flight. The first uncrewed orbital mission is expected in 2026; the crewed mission is currently expected no earlier than 2027.
Key Details
- Orbital altitude: ~400 km (low Earth orbit).
- Mission duration: Up to 7 days for the crewed mission.
- Crew: 2–3 astronauts per crewed mission.
- Crew module mass: approximately 5.3 tonnes.
- Launch vehicle: LVM3 (Launch Vehicle Mark-3, formerly GSLV Mk III).
- Astronaut candidates: Four IAF pilots selected; trained in Russia and India.
- Vyommitra: ISRO's humanoid space robot, to fly on uncrewed test missions.
- Crewed mission target: No earlier than 2027.
SOLVE's parachute validation tests are a mandatory qualification step before the crew module can be certified for carrying humans — the re-entry and recovery system is the last line of safety.
SOLVE — Sub-Orbital Launch Vehicle for Experiments
SOLVE (Sub-Orbital Launch Vehicle for Experiments) is a compact, solid-motor-based sub-orbital test vehicle developed by ISRO specifically to conduct integrated parachute validation tests for the Gaganyaan crew module. During test flights, SOLVE will carry a mass-representative dummy version of the crew module to altitudes of 10–17 km, after which the module is released to free-fall. Engineers then observe whether the sequenced parachute deployment successfully decelerates the module to safe splashdown speeds. The solid motor of SOLVE is derived from and modified based on the PSLV (Polar Satellite Launch Vehicle) strap-on motor, with key modifications including a slow-burn-rate propellant, a straight nozzle design, and a secondary injection thrust vector control (SITVC) system for attitude control during ascent.
Key Details
- Full form: Sub-Orbital Launch Vehicle for Experiments.
- Purpose: Integrated parachute validation for the Gaganyaan crew module deceleration system.
- Test altitude: 10–17 km (sub-orbital).
- Motor heritage: Derived from PSLV strap-on booster; modified with slow-burn propellant, straight nozzle, and SITVC.
- First solid motor ground test: 3 July 2026, Sriharikota — successful.
- Test site: Satish Dhawan Space Centre (SDSC), Sriharikota, Andhra Pradesh.
The July 2026 ground test is the first qualification milestone for SOLVE; successful flight tests with SOLVE will clear the parachute system for use on crewed Gaganyaan missions.
Gaganyaan Deceleration System — Parachute Sequence
Safe re-entry from orbit requires that the crew module, travelling at hypersonic speeds during atmospheric entry, be decelerated to a safe landing speed before splashdown in the sea. Gaganyaan's deceleration system uses a carefully sequenced deployment of ten parachutes to reduce the module's descent velocity from approximately 216 m/s (~700 km/h) during high-altitude descent to under 11 m/s (~30–40 km/h) at sea-level splashdown. The sequence is: (1) two apex cover separation parachutes deploy first to expose the parachute bay; (2) two drogue parachutes deploy to stabilise and initially decelerate the capsule; (3) three pilot parachutes then each extract one of three large main parachutes, which provide the primary deceleration down to splashdown speed. The crew module is recovered at sea by the Indian Navy.
Key Details
- Total parachutes in sequence: 10 (2 apex cover + 2 drogue + 3 pilot + 3 main).
- Entry velocity: ~216 m/s (approximately 700 km/h) during descent.
- Target splashdown speed: Under 11 m/s (~30 km/h).
- Splashdown medium: Sea (Bay of Bengal recovery zone); Indian Navy responsible for recovery.
- SOLVE's role: Carry and release a dummy crew module at 10–17 km to test this full parachute sequence in realistic conditions.
- Earlier milestone: ISRO successfully tested the drogue parachute system in December 2025.
SOLVE enables full integrated testing of this ten-parachute sequence in realistic flight conditions — a qualification requirement that cannot be adequately replicated in ground tests alone.
India's Space Programme — Institutional Framework
ISRO (Indian Space Research Organisation) is the primary space agency of India, functioning under the Department of Space, which reports directly to the Prime Minister. The Space Commission is the apex body for space policy. The IN-SPACe (Indian National Space Promotion and Authorisation Centre) was established in 2021 to regulate and promote private sector participation in space activities. NewSpace India Limited (NSIL) is the commercial arm of ISRO for operationalizing space missions. The Space Activities Bill (proposed) seeks to provide a statutory framework for India's space sector including liability, licensing, and private participation.
Key Details
- ISRO: Under Department of Space; reports to PM.
- IN-SPACe (2021): Regulatory body for private space sector.
- NSIL: Commercial and operational arm of ISRO.
- Human Spaceflight Centre (HSFC): ISRO centre dedicated to Gaganyaan programme management.
- India's first human in space: Rakesh Sharma, aboard Soviet Soyuz T-11 in 1984 — not an ISRO mission.
Gaganyaan will make India only the fourth country (after USA, USSR/Russia, and China) to independently launch humans to orbit — SOLVE tests are part of the critical path to that milestone.
- SOLVE stands for Sub-Orbital Launch Vehicle for Experiments.
- First SOLVE solid motor ground test: 3 July 2026, Sriharikota (SDSC-SHAR).
- SOLVE test altitude: 10–17 km (sub-orbital).
- SOLVE motor derived from PSLV strap-on booster, modified with slow-burn propellant and SITVC.
- Gaganyaan crew module mass: approximately 5.3 tonnes.
- Orbital altitude for crewed mission: 400 km.
- Mission duration (crewed): up to 7 days; crew size: 2–3 astronauts.
- Deceleration parachute sequence: 10 parachutes (2 apex + 2 drogue + 3 pilot + 3 main).
- Entry speed: ~216 m/s; target splashdown speed: under 11 m/s.
- First crewed Gaganyaan mission expected: no earlier than 2027.
- First uncrewed orbital test mission expected: 2026.
- Launch vehicle for Gaganyaan: LVM3 (GSLV Mk III).