Stage separation dynamic analysis of upper stage of a multistage launch vehicle using retro rockets

K e y w o r d s J e t t i s o n i n g system, Retro-rocket, Jet damping, Pyro, Relative velocity, Relative distance, Launch vehicle. N O M E N C L A T U R E Az launch azimuth (deg) h altitude of separation (km) I inertia tensor (kg-m 2) t Time (s) mM, ms mass of the ongoing and spent bodies (kg) RE, Rp, Rs Earth's equatorial radius, polar radius, radius at the surface (km) r, q, p body angular velocity along yaw, pitch and roll axes (deg/s) X, Y, Z body axes yaw, pitch and roll ~oxt = (¢g + Fr+ ~j) total external force due to gravity, thrust, and jet damping (N) *Author to whom all correspondence should be addressed. The authors would like to thank the reviewers for their valuable suggestions to improve the clarity of the paper. 0895-7177/05/$ see front matter (~) 2005 Elsevier Ltd. All rights reserved. Typeset by ~4A&9-TEX doi: 10.1016/j.mcm.2005.02.001 850 D. JEYAKUMAR et al. Mext ~total external moment due to gravity, thrust and jet damping (N-m) d T F1 position vector in ECI frame (XI, YI, ZI) (m) ¢,0,¢ ~'c~ position vector of the body CG offset (m) aSGc velocity in the body frame (m/s) m" propellant mass flow rate (kg/s) e T thrust (N) t~ rT distance of thrust location from main body CG (m) ~/~ IcG distance of CG from nose tip along longitudinal axis (m) distance of thrust location from nose tip along longitudinal axis(m) distance of thrust location from vehicle longitudinal axis (m) body orientation angles along yaw, pitch and roll in LPI frame (deg) geocentric latitude of the launch station (deg) launch station longitude (deg) Earth's gravitational constant (.~3/s2) Earth's angular velocity (rad/s) 1. I N T R O D U C T I O N Launch vehicles almost always employ multistage using the concept of staging for boosting payload capabilities. This in turn requires jettisoning the spent stages. The dynamics of separating bodies has received the attention of several investigators [1-24]. Chubb [2] has constructed collision boundaries between two separating stages. Dwork [3] and Wilke [4] provide valuable insight into disturbances caused by separation mechanisms in a spinning setup. Considerable amount of aerodynamic data including stability derivatives have been generated for space shuttle type of configurations involving winged bodies [5,6]. The data so gathered have been utilized for separation dynamics investigation [8], Waterfall [9] investigated multispring system for separation and spinning and nonspinning bodies. Longren [10] analyzed spin stabilized rockets with guide shoes and rails constraining the lateral motion. Hurley and Carrie [11] reviewed the genesis of a four bar linkage separation system and carried out the analysis for separation of parallel staged shuttle vehicles. Subramanyam [13] developed a general model for spring assisted stage separation. Biwas [15] investigated several aspects of separation for strap-on from the launch vehicle. The aerodynamics of separation is rather complex due to relatively large angles of incidence, intricate geometry, and the involved interference phenomenon. Moraes Jr. et al. [16] have developed the Navier-stoke's code, which provided a good agreement with the experiments only on the nose part of the ongoing stage. Lochan et al. [17-20] have analyzed the separation dynamics of strapon boosters from the core rocket utilizing the wind tunnel simulation data for dynamic forces. Cheng [21] has developed an analytical procedure based on a coupled gas / structure model to simulate the fairing separation events. The procedure was validated by comparing the analysis results with full-scale payload fairing separation test data of Titan IV launch vehicle. Seongjin Choi et al. [22] have developed an efficient three-dimensional aerodynamic-dynamic coupled code to simulate the separation dynamics of strap-on boosters in the dense atmosphere. Jeyakumar and Biswas [23-25] have provided stage separation system design and dynamic analysis of ISRO launch vehicles. A typical launch vehicle may involve several separation events such as strap-on separation, stage separation, heat shield separation, ullage rocket separation and spacecraft separation (see Figure 1). In a multistage rocket configuration the most important event is staging. The staging process during the flight of a launch vehicle comprises of a series of events, which takes place in transferring the regime of an ongoing stage to that of the next stage. Obviously, the process commences from the detection of the burn out of the ongoing stage, and continues with the ignition of the next stage and the separation of the spent stage. Ignition of the next stage and the separation of the spent stage may takes place concurrently or with a time difference and in any order, depending on vehicle configuration and mission requirements, and they may be Stage Separation Dynamic Analysis 851 ORBIT SEPARATION OF J SPACECRAFT SEPARATION OF SPENT STAGE / ~ SEPARATION OF PAYLOAD FAIRING