Hypersonic Weapons | 1 IDSA Occasional Paper No. 46 HYPERSONIC WEAPONS AJEY LELE 2 | Ajey Lele Institute for Defence Studies and Analyses, New Delhi. All rights reserved. No part of this publication may be reproduced, sorted in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photo-copying, recording or otherwise, without the prior permission of the Institute for Defence Studies and Analyses (IDSA). ISBN: 978-93-82169-76-5 First Published: July 2017 Price: Rs.120/- Published by: Institute for Defence Studies and Analyses No.1, Development Enclave, Rao Tula Ram Marg, Delhi Cantt., New Delhi - 110 010 Tel. (91-11) 2671-7983 Fax.(91-11) 2615 4191 E-mail:
[email protected] Website: http://www.idsa.in Cover & Layout by: Geeta Kumari Printed at: M/s Manipal Technologies Ltd. Hypersonic Weapons | 3 HYPERSONIC WEAPONS The proprieties of sound have fascinated humans for a long time. The first known theoretical treatise on sound was provided by Sir Isaac Newton in his Principia (1687). Since then, scientists have been researching on quantifying the speed of sound. The speed of sound estimated by Newton was around 15 per cent less than the actual (the standard value for speed of sound1 has been decided based on the experimentation carried out during 1963). On 14 October 1947, the sound barrier was broken for the first time in a manned level flight in a Bell X-1, piloted by Chuck Yeager. With this began the age of the supersonic aircraft. Objects which move at supersonic speeds2 actually travel faster than the speed of sound.