- Why in news
- On 9 January 2026, DRDO's Hyderabad-based DRDL ground-tested an actively cooled full-scale scramjet combustor for over 12 minutes at its SCPT facility. It is a step in India's hypersonic cruise missile programme.
- What it is
- A scramjet is an air-breathing engine that burns fuel in a supersonic airflow. It has no rotating compressor and takes oxygen from the atmosphere, so it needs no onboard oxidiser. A hypersonic cruise missile uses such an engine to fly at more than Mach 5 for long periods.
- Who tested it
- DRDL, the Hyderabad-based DRDO laboratory, ran the test. The combustor and test facility were designed by DRDL and built by industry partners.
- Earlier test
- A subscale long-duration test was held on 25 April 2025.
- Speed class
- A hypersonic cruise missile can exceed five times the speed of sound, over 6,100 km/hr, for extended periods.
- Engine principle
- The engine is air-breathing and uses supersonic combustion to sustain long-duration flight.
Don’t confuse with Scramjet vs ramjet: A ramjet burns fuel in subsonic airflow after slowing the air. A scramjet burns fuel in supersonic airflow.
Don’t confuse with Hypersonic cruise vs hypersonic glide vehicle: A cruise missile is powered by an air-breathing engine throughout flight. A glide vehicle is boosted by a rocket and then glides unpowered.
Defence: Prelims tests exercises (with whom), equipment (who makes it) and firsts.
No Mains angle on this one yet.
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.A scramjet engine takes oxygen from the atmosphere and has no rotating compressor.
- 2.The full-scale scramjet combustor ground test of January 2026 was the first long-duration test in the programme, with no earlier test.
- 3.A hypersonic cruise missile can fly at more than five times the speed of sound for extended periods.
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.The scramjet combustor was tested by DRDL, a DRDO laboratory based in Hyderabad.
True. DRDL, Hyderabad, conducted the test.
2.The ground test of the full-scale combustor ran for over 12 minutes.
True. The run time was over 12 minutes.
3.A scramjet engine carries its own oxidiser and uses a rotating compressor to burn fuel.
False. A scramjet is air-breathing, takes oxygen from the atmosphere, and has no rotating compressor.
4.The test described was the first long-duration test, with no earlier test of the programme.
False. It followed a subscale long-duration test on 25 April 2025.
5.The scramjet engine sustains flight through supersonic combustion.
True. Fuel burns in a supersonic airflow inside the combustor.
6.The combustor and test facility were designed and developed entirely by private industry, with no DRDO role.
False. DRDL designed and developed them; industry partners realised them.
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.