Mangalyaan's main engine test fired for 4 seconds.

William Robinson writes: Before the spacecraft is scheduled to enter Mars orbit, Indian Space Research Organisation (Isro) scientists reignited the Mars Orbiter Mission spacecraft's main engine for four seconds as a trial. The liquid apogee motor (LAM) engine has been idle for about 300 days since the spacecraft left the Earth's orbit on a Martian trajectory on December 1, 2013. The short-duration test was to ensure that the engine is in good shape for the 24-minute crucial manoeuvre on Wednesday.