Design, Development, Testing, and In-ftight ...

JOURNAL

OF SPACECRAFf

AND ROCKETS

VoL 49, No.4, July-August

2012

Design, Development, Testing, and In-ftight Qualification of a Parachute Recovery System G. Guidotti,* c. Richiello,t P. de Matteis," and G. Russo! Centro Italiano Ricerche Aerospaziali, 81043 Capua, Italy DOI: 1O.2514/l.A32163 Development of aerodynamic decelerators for aerospace applications is rather a complex and challenging endeavor, and it is even more so when it has to be conceived for winged systerns to be recovered off their flight in supersonic conditions. In the case of the Centro Italiano Ricerche Aerospaziali unmanned space vehicle Polluce, a somewhat revolutionary approach was adopted for acquisition or the parachute recovery system, based upon adoption of a terminal area energy management strategy and the use of a completely commerciaI off-the-shelf onestage-only parachute system used in generai aviation aìrcraft, The development process actually required implementation of a great engineering effort to customize the activation system, which in generaI aviation aircraft is usually performed only by the pilotin case of emergency. The parachute recovery system ofPolluce was successfuUy used during drop transonic flight test #2, ensuring a safe mission termination and the vehicle recovery after sea splashdown.

Nomenclature

II.

I.

Mission Description

Drop transonic flight test #2 consisted of three main phases (Figs. 2 and 4) [3]. In the ascent phase, a stratospheric balloon took the vebicle up to 24 km over a safety release area, ternporarily restricted to civil maritirne and air traffico In the maneuvered phase, the vehicle was released from the balloon and performed a 140 s gliding flight (no engine) accelerating up to about Mach 1.2; in this pha e, the onboard guidance system autonomously controlled the vehicle to fulfill the testing objectives (i.e., an angle-of-attack sweep at Mach maximum and double-bank maneuver for terminal area energy management sirnulation) and finally to decelerate the system with a pitch-up maneuver, driving it into the parachute operative envelope and sending to the onboard computer a flight-termination command for the parachute system activation. Finally, in the recovery phase, the vebicle was recovered off its flight path and was deceIerated by the parachute until splashdown into sea with a nose-down attitude andan impactspeedin therange of 7.5-8 m/s.

parachute clrag area

Introduction

RE unmanned space vehicles prograrn carri ed out by Centro Italiano Ricerche Aerospaziali (CIRA) in the framework of the Italian National Aerospace Research Program aims at provicling a farnily of experimental vebicles or f1ying test beds based on aerodynamically efficient winged configurations to carry out inf1ight testing and validation of novel technologies and liftingmaneuvered reentry capability for future spacecraft. The f1ying test bed platforms are exploited by drop flight tests via stratospheric baUoons (Figs. 1 and 2). Flight and m.ission operation aspects related to the low-atmosphere part of a reentry pattern are covered «40 km) using two vebicles (Fig. 3), with the main focus being investigation of aerodynam.ics, structures, and flight control at transonic and low supersonic speeds, which are typical of the approach and landing phase of a reentry vehicle [1,2]. Flying test bed #1 was dubbed Castore and performed its maiden flight in February 2007 in the Tyrrhenian Sea (Italy) after being released from a baUoon at an altitude of about 20 km. Ascent and flight were completed succe sfully, and the scientific and housekeeping data were recovered via telemetry. However, at the end of the rnission, the three-stage parachute system had a failure of the supersonic drogue, causing a free fall of the vehicle and its loss in the sea. Flying test bed #2, named Polluce (Fig. 3 and Table l), was ready in June 2007, and its experimental flight was originally planned for the beginning of 2008, although then it was reschedu1ed for the beginning of201O. The main requirement for the second vebicle was to develop a completely new parachute recovery system to guarantee the accomplishment of the second flight test by ensuring the vebicle recovery after the flight.

T

ID. A.

Polluce Recovery System

Description

The Polluce recovery system is composed of three main subsystems (Figs. 5 and 6): the parachute assembly, the rocket activation system, and the recovery system power unit. The parachute assernbly includes a commercial rocket-deployed parachute, usually installed on the general aviation aircraft Cessna-182, along with its canister equipped with CIRA-custornized brackets for ìts proper installation onto the vehic1e. The parachute is a 223 m2 extended-skirt round-canopy with slider reefìng. The rocket activation system is devoted to the parachute extraction and deployment. It includes the commerciai item rocket rnotor assembly BRS900F and the rocket activation device (solenoid type), which was engineered and developed by CIRA. The recovery system power unit is devoted to initiate and power the activation device, and it includes the batteries, the electronic board, the fìight safety pio, and the ground-arrning connector, It is a completely customized item.

Received 4 July 2011; revision received 14 October 2011; accepted for publication 22 October 2011. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. Ali rights reserved. Copies of this paper may be made for personal or internai use, on condition that the copier pay the $10.00 per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923; include the code 0022-4650/12 and $10.00 in correspondence with tbe CCC. 'Project Engineer, Space Access, Vehicles Division. "Project Manager, Space Access, Vehicles Division. iproject Manager, Propulsion Division. §Manager, Office for Institutional Relations Development.

ominal Operatìon and Functioning In the prelaunch phase, an arrning connector was screwed onto the recovery system power unit chassis to provide a fust arming of the unir. A flight safety pin also inserted onto the recovery system power unit is later extracted automatically from the chassis by means of a static line as the vehicle is released from the balloon chain, allowing for the definite arrning of the system. Then, at the end of the Polluce

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701

Fig. 2

Drop transonic

flight test #2: mission concept and scenario.

Fig. 1 Polluee'H'!I:1idi~ 21:. pr1d:21:mch.

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_ and altitude 7 km, a parachute• _. the onboard computer to the PU). This provides the current solenoid puller), which moves in ide the racket launch tube. '" the igniter and causing igniter r'"'"'-""':::' rhe firing of the main rocket. hute, causing its deployment -down and deceleration until sea

IY. A.

Fig. 3

somehow feature the main functions already foreseen in the previous one. Finally, the design had to be compliant with frozen mechanical and electrical interfaces, physical arrangement, as weli as constrained mass and volume budgets of the vehicle as a whole system. B.

The developmem recovery system was a challenge because of the neec itical subsystem, such as the one devoted to the reco by maintaining the ongoing test campaign schedule '" \ ith the mission and vehicle interface and layout Table 2). First, from a p _ .poìnt, the ftight test #2 campaign had to take piace 6 mon°l-the postftight analysis of the test #1, issued in lune _(Xr. TI actually imposed the need far a new recovery ) em erable choice for the Polluce vehicle because of the failure of tbe originai recovery system implemented on the Castore. The Cas re recovery ystem in fact was based on a complex three- tage parachute y tem conceived to be able to recover the vehicle ali along i fìight path, from high altitude and supersonic conditions up to the nominai fìight terrnination point at 10 km altitude and ~1a hO. - Second, far the Polluce. the budget was criticai because of the very high cost for the developmenr and qualifìcation that would arise in case a similar three- tage y tem had to be chosen. Third, concerning functionalities and performances. the new recovery system had to o

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Design Approach/Concept

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redundant architecrure was adopted, the main elements being: two rechargeable ~1~~1H batteries for redundancy, the electronic board with ali acUIaIO and control interfaces, the flight safety pin, and the ground-arming connector. The mechanical chassis was fully customized to arrange the unitinto the lirnited volume available in the rear bay of me vehi le. However, an effective thermal control design was also implemented.. based on thermal insulation and integrated heaters for high-altirude u e. Moreover, a reliability analysis was executed. yielding the excellent result of 0.999882. Dedicated electrical ground upporr equipment was also provided to allow onground t and prelaun h operation .

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Y. On-Ground

Qualification

On-ground qualificarion 'as necessary to verify the functional and performance oftbe id-based activation device typically used in industrial applicati - eli as of the completely custom recovery system power DL The two items were tested both as stand-alone de- ~ as an integrated assembly. Different tests were execured . ambient conditions, but also at relevant environrnent OI.K.ll~UU~ A.

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properly even at relevant environmental conditions, providing the rimely and successful activation of the igniter.

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Ambient t . r.erfaeing i ues as well as simple functional verificaricn ar araoìem temperature and pressure. A rocket mock-up was ying exactly the same firing mechanism as tbe ",._ During ambient tests, the activation device was first \ ed by an extemal power supply and then as activated ~ y tern power unit on a test bench (Fig. 13).

VI.

In-Flight Qualification

and Postflight Analysis

On 11 Aprii 2010, the Polluce successfully performed drop transonic flight test #2 test over the military test range in the Tyrrhenian Sea (Sardinia, Italy). After a 137 s nominai maneuveredautonomous flight, the onboard computer commanded the parachute activation, which occurred nominally at Mach 0.117 and altitude 5166

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y tem power unit was able and that the solenoid deviee ::xrllani·ism. further tests were executed -«"I~:T.!Inre t t chamber (Fig. 14) in the p ure of 1.0 atrn. The solenoid o se ors to record the temperature - were uccessful with respect to the 1OIl~'temoerarure. 1rh21 G;1e

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Finally, thermov 'ere performed to couple the inflight low-temperamre aod ure conditions and thus qualify on the ground for tbe aerosoace eavironment the overali design of the flightconflgurario '. ;herecO\'erysystempowerunit, the activation device, = mechanism (Fig. 15). The test arti le '-;re- tep thermal cycle as described in Table 6. All ofthe t "ed uece fully and demonstrated that the recovery . along with its thermal insulation as well as the coupled with the igniter worked

weli as from the analysi of flight data, it seems that the parachute recovery system worked proper1y in all its phases, that is: soJenoid activation and pull, rocket ignition, paraehute extraction, deployment, and inflation. Moreover, the system successfully performed the vehicle pitch down and deceleration, thus providing it with the nominal steady-state velocity to allow its safe recovery after sea splashdown (Figs. 16-19). Among the onboard instrumentation installed onto the vehicle, a digital three-axis accelerometer was included to measure the g-loads produced at the parachute activation. The acquired data provided pretty good evidence of the rocket shock, the parachute snatch, as well as the peak force and the steady-state deceleration produced during the whole process (Figs. 20 and 21). Moreover, the aforementioned one-dimensionaJ model of the parachute developed by CIRA was run again with the actual flight condition at which the parachute was deployed during flight #2. The simulation results (Fig. 22) show a peak force along the longitudinal

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automati m and qualifìcation grade required on space vehicles, as in the case of the activation and power supply components.

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axis of about 3.5 g vs an actual peak force produced during the ftight of about 3.7 g. Hence, there is a good agreement between the two values.

VIT. Conclusions The recovery system designed for the second ftying test bed, Polluce, in the framework of the ltalian space program, was successfulJy performed during the second drop transonic fìight test in April2010. The overall design process was carried out by the Centro Italiano Ricerche Aerospaziali project team after the failure of the system developed and implemented for the fìrst vehicle unit that flew in February 2007. The design relies upon the use of cornmercial offthe-shelf components grafted onto custom subsystem architecture for a recovery parachute system. The distinguishing features of this design are the adoption of a certified parachute and igniter components, currently applied to general aviation aircraft, and a customized automatic activation system. The overall design went through a complete ground qualification process before fìight, according to standard procedures used in space applications. Although developed to resolve the failure that occurred during the fìrst fìight, this custom design solution rnight have interesting, beneficial results for both space and aeronautical applications. Indeed, it has been proven that space-transportation-oriented applications can really benefit from the highly reliable aeronautical standard, as in the case of the parachute recovery system. On the other side, the aeronautical applications can benefit from the level of

The authors wish to acknowledge the supplier of the parachute assembly, the BRS Aerospace Company (United States) for their support during design and integration; the supplier of the power unit, the Technosystem Development Company (ltaly); and the ltalian authority of the military test range in the Tyrrhenian Sea (poligono Interforze Salto di Quirra, Sardinia). Finally, the authors wish to express their gratitude to the whole project team that made drop transonic flight test #2 a successo

References [I] Russo, G., ''USV Programme Progress and Perspectives," 3rd Intemational ARA Days, Association Aéronautique et Astronautique Française AA-1-2011-34, Arcachon (France), 2-4 May 2011. [2] Russo, G., ''USV Status 2011: New Steps Ahead,' 17th A1AA International Space Piane and Hypersonic Systems and Technoiogies Conference, AIAA Paper 2011-2242, San Francisco, CA, 11-14 Apr. 2011. [3] De Matteis, P., Marino, G., RichielJo, C, and Russo, G., "The Italian Unmanned Space Vehicle FTB_I Back to F1y: Experimental Objectives and Results of the DTFT _2 Mission,' 61 st International Astronautical Congress, IAC Paper IO-D9.2.8, Prague, Czech Republic, 27 Sepr.IOcr. 2010. [4] Corraro, F, Morani, G., Nebula, F, Cuciniello, G., and Palumbo, R., "GN&C Technology Innovations for TAEM: USV DTFf2 Mission Results,' 17th A1AA International Space Piane and Hypersonic Systems and Technologies Conference, AIAA Paper 2011-2262, San Francisco, CA, 11-14 Apr. 2011. [5] Knacke, T. W., Parachute Recovery Systems Design Manual, Ist ed., Para Publishing Co., Santa Barbara, CA, 1992. [6] Knacke, T. w., Ewing, E. G., and Bixby, H. w., "Recovery Systems Design Guide," AFFDL TR 78-151,1984. [7] Anderson, J. D. JI., Fundamentals of Aerodynamics, McGraw-Hill, New York, 2007. [8] Mohaghegh, F, and Jahannama, M. R., "Decisive Roll ofFilling Tirne on Classification of Parachute Types," Journal of Aircraft, VoI. 45, o. l, Jan.-Feb. 2008. [9] Pepper, W. B., and Maydew, C. R., "Aerodynamic Decelerators: An Engineering Review,' Journal of Aircraft, VoI. 8, o. I, Jan. 1971. [lO] Lee, K. c., "Modeling of Parachute Opening: An Experimental Investigation,' Journal of Aircraft, VoI. 26, NO.5, Feb. J 988.

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