The Tunguska Airburst as an Energy and Altitude Budget: What Burst Height Does the Stated Energy Require?

This paper computes a complete entry budget for the Tunguska airburst, working only from published values and stated assumptions. The nominal body has a diameter of 60 metres at a bulk density of 2.70e+03 kilograms per cubic metre, giving an incoming mass of 3.05e+05 tonnes. At the published entry speed of 15 kilometres per second its kinetic energy is 8.21 megatonnes of TNT equivalent. At the characteristic altitude of 8 kilometres the exponential atmosphere has a density of 0.403 kilograms per cubic metre, the ram pressure on the body is 90.7 megapascals, the stagnation heating flux is 6.81e+05 megawatts per square metre, and the aerodynamic deceleration is 85.6 times terrestrial gravity. The ram pressure first reaches representative material strengths at computed altitudes of 57, 40.5 and 28.9 kilometres for the weakest, intermediate and strongest cases examined. All values are computed by the deposited program from the stated inputs; scenario calculations accompany every headline figure so that the sensitivity of each conclusion to its inputs is visible in the same record.