An exploding rocket started a fire that quickly burned through five hectares at Kyneton on March 30, triggering a number of community warnings.
A group of Monash University students were conducting an experiment with rocket engines when the grassfire took hold.
Emergency services were called to the scene at a property on Baynton Road about 2.40pm and quickly contained the blaze.
Winds at the time were gusting to 24 km/h and the terrain was dry on the edge of a plantation. The students had no firefighting equipment with them.
Police officers arrested a 22-year-old Mornington man and a 23-year-old Oakleigh South man at the scene.
They were interviewed and released pending further enquiries.
