www.tjprc.org SCOPUS Indexed Journal editor@tjprc.org COMPARISION OF LIFITING RE-ENTRY AND BALLISITC RE-ENTRY A. RATHAN BABU 1 , P. VIJAY KUMAR 2 , B. PRAVEEN 3 & R. SURESH KUMAR 4 1,4 Assistant Professor, Department of Aeronautical Engineering, Institute of Aeronautical Engineering, Hyderabad, Telangana, India 2 Department of Aeronautical Engineering, Institute of Aeronautical Engineering, Hyderabad, Telangana, India 3 Assistant Professor, Department of Aeronautical Engineering, MLR Institute of Technology, Hyderabad, Telangana, India ABSTRACT This paper highlights comparison of lifting re-entry and ballistic re-entry. 3-D. O. F code is developed and used for comparing the different re-entries. The main objective of this paper is to minimize deceleration on re-entry body and find the optimal flight path angle ranges to escape under and overshoot conditions of re-entry. KEYWORDS: Lifting Re-entry, Ballistic Re-entry, Flight Path Angle & Drag Coefficient Received: Mar 12, 2018; Accepted: Apr 02, 2018; Published: Apr 26, 2018; Paper Id.: IJMPERDJUN201812 INTRODUCTION Re-entry is used for different purposes like planetary and interplanetary, and re-entry is categorized into three types i.e., lifting, ballistic, skip re-entry. During lifting re-entry lift coefficient is not zero and it is assumed to be a small value. In re-entry, the major aerodynamic force is a drag, which plays a major role in the decelerating body from high speeds in the order of 8-10 km/s to terminal velocity. During ballistic re-entry lift coefficient is zero and body fall on the surface of the planet under the influence of gravitational force. In skip re-entry, sometimes body lifts off and returns to its state. In this process, body possess lift at some instant such that P. E is increased and K. E is decreased for the conservation of total energy. During re-entry, body has a maximum deceleration which depends on initial flight path angle and entry velocity. If flight path angle is increased then body undergoes the steepest re-entry. For manned mission, re-entry deceleration level shouldn’t increase beyond ‘4g’ level. When a body is entering the planet’s atmosphere where density level is increased such that drag on the body will increase. Therefore, deceleration level is increased and heat load on the body will also increase. Deceleration level on the body is proportional to the square of the velocity and heat load on the body is proportional to the cube of velocity. Flow classification on the body is based on the Knudsen number(Kn)[4]. Kn≥10 is considered as (free-molecular), whereas 0.01≤Kn≤10 is considered (transition), and Kn<0.01[2] is considered as(continuum-flow) . =   (1) Original Article International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN (P): 2249-6890; ISSN (E): 2249-8001 Vol. 8, Issue 3, Jun 2018, 111-116 © TJPRC Pvt. Ltd