METHODS OF BALLISTIC SUPPORT AND SUPERVISION OF RESEARCH AND TECHNOLOGICAL EXPERIMENTS OF FOTON SC Jury. M. Ustalov RSC TsSKB-Progress, Samara, Russia Abstract A wide range of research and technological experiments within Russian and international space programs is made on Foton SC. Complication of experiments and research requires updating ballistic and navigation support (BNS) of SC flight. Results of updating methods, facilities and technologies of BNS, involved in Foton SC #11 and 12 flights, are presented. Methods and means of SC BNS provide for easy use of ballistic and navigation data in the interests of research and technological experiments. A wide range of research and technological experiments within Russian and international space programs is made on Foton SC, success (efficiency) of experiments requiring the reception of various ballistic information. Increase in scientific hardware, installed on Foton SC and complication of experiments and research, involving it, require continuous updating ballistic and navigation support of SC flight. Results of updating BNS methods, means, technologies in Foton SC #12, 13 flights are presented below. SC ballistic and navigation support is a complex of software methods, algorithms, computing hardware with software and administrative measures, designed for receiving the desired navigation and ballistic information with the required accuracy and within the required time and its delivery to the user. That s why Foton SC flight BNS targets can be divided into the following phases: ballistic-design justification phase; phase of development (optimization and adaptation) of timely SC BNS methods, facilities and technologies and supervision of research experiments; in-flight timely SC BNS phase, comprising determination and issue of ballistic information, required for planning and control over research and service hardware as well as for processing results of research experiments. Ballistic-design justification phase involves: selection of orbital parameters, estimation of ballistic SC life time in orbit to specified altitude limit, launch dates and time, in flight SC illumination estimation, SC flight track, mutual visibility conditions of SC/ground command station, SC and receiving station (RS), estimation of descent maneuver parameters and descent vehicle (DV) descent trajectories and estimation of DV landing point spread. This phase determines external conditions of experiments and input data for their planning, for example, SC flight altitude, values of aerodynamic impacts, SC light/shadow times, values of g-loads and velocity head at DV descent trajectory. As Foton SC is non-maneuverable, orbital parameter choice and ballistic life-time estimation (considering spread of orbital parameters when launched by launch vehicle, upper atmosphere density variations, res ulting from heliogeophysical factors) are made to determine conditions and time of programmed SC flight. It is well-known that minimization of residual microaccelerations is an important research and applied problem of design of space platforms for production of new materials in orbit. Microacceleration value essentially affects physical processes of new material production. That s why SC, involving experiments on material production procedure development, should have microacceleration level below 10-6 from acceleration of free fall. Aerodynamic component of microacceleration, affecting SC in flight, was studied within Foton SC ballistic-design justification in order to work out recommendations on orbital parameters. Research was made by numerical simulation of SC movement in orbit using developed procedures and software. In view of essential atmospheric density fluctuations, estimation of aerodynamic microacceleration component values was made using dynamic model of atmospheric density for the range of solar activity index change during the current (23 - d ) eleven-year cycle. We considered a class of orbits, where Soyuz LV launched SC with characteristics, close to Foton. Generalized results of aerodynamic microacceleration component estimations are given in Fig.1 for maximal mean yearly solar activity level F 0 = 200x10-22 W/(m 2 Hz) for the 23 -d eleven-year cycle. Proceeding from the planned launch period of the following Foton SC, Fig.1 also shows results of estimations of aerodynamic microacceleration component for maximal mean yearly solar activity level F 0 = 130x10-22 W/(m 2 Hz), which is expected in 2002, for recommended orbits /4/. As Foton #11, 12 operational orbit is elliptical with a perigee altitude of h p =226km and an apogee altitude of h a =394km, as seen from Fig.1, there is an essential (approximately of an order) change of aerodynamic acceleration component in flight orbits. According to research, orbits with h p =252-265km and H a =394-373km are recommended for advanced Foton SC, which enable to decrease maximal in-orbit aerodynamic microacceleration components and accordingly amplitude of its change more than twice. In terms of results of ballistic design justification, SC BNS/research experiment supervision methods, facilities and procedures are developed and verified. Trends of modification of Foton # 11 and 12 BNS methods, facilities and procedures resulted, in particular, from experiments with recoverable Mirka scientific hardware (Germany) on Foton-11 SC and Fluid-Pac hardware (European Space Agency) and TeleScience (Swedish Space Corporation) on Foton-12. Modification aims at timely delivery of the desired ballistic data to Client companies, performing experiments with scientific hardware. Structurally, Mirka hardware is sphere of 145-155 kg, 1m in diameter, mounted on Foton descent vehicle. Mirka deceleration is simultaneous with SC deceleration for DV descent by means of powder retrorocket engine (PRE).
Mirka separates from SC 45±1s and DV/adapter module (AM) separate 52 ±1.3s after decelerating pulse and PRE shut-off. After that Mirka and DV descend autonomously along ballistic trajectories until their parachute system deployment. During Foton-11 pre-launch processing within ballistic-design justification was proved possibility to carry out this experiment, namely were computed DV and hardware descend parameters, estimated their loading point separation and their relative distance between DV and hardware. Diagram and parameters of DV and Mirka hardware descent are presented in Fig. 2 with MDT meaning Moscow Decree Time. To provide timely BNS of SC Foton 11 flight was developed special software (SS) for computation of DV SC Foton and Mirka hardware descent ballistic data, DV and Mirka hardware descent trajectories parameters, positions of their landing points with their spread and mutual distancing estimation. SS is built taking into account computer modularity using high-level languages. To provide SS computation reliability input data entered by an operator is checked, warning messages and error messages are issued, data is protected from any kind of informational actions not foreseen in documentation. The developed SS was successfully serviced by TsSKB specialists in GCC operating ballistic center during SC Foton 11 flight. Checking, control and reception of data concerning results of experiments on FluidPac equipment is done with TeleScience equipment from ESRANGE RS in Kiruna, Sweden. Control implies transfer of SC Foton OP, RV and TD to ESRANGE PRS in order to?, 10-5 m/s 2 set ESRANGE aerial systems to bear on SC Foton with the required accuracy and time. The tasks of ESRANGE RS ballistic support are solved with TsSKB computer utilities and software. Records of ballistic information exchange were developed during SC Foton 12 pre-launch processing jointly with European Space Agency (ESA) (Table 1); as well were developed procedures of processing and transmission of ballistic data from TsSKB to ESRANGE RS. Diagram of SC Foton 12 ballistic data exchange is given in fig. 4. Optimization of methods of ballistic support and supervision of research and experiments for SC Foton, as well as timely delivery of necessary ballistic data is done with the Center of General Designer (Center of GD) facilities, based in TsSKB. Main functions of the Center of GD are the following: efficient interaction between the Client and TsSKB for joint decision-meking; provision of the Client with complete data concerning LV Soyuz and PL (SC with scientific hardware) status by telephone and by fax broadcasting of LV Soyuz launch and video imaging of LV Soyuz and SC flight scheme in real time timely registering of the flight process and issuing of express-report after injection of PL into orbit. Expedience and potency of the Center of GD for supervision of SC flight was proved during launches of SC Globalstar with LV Soyuz (with Kick Stage IKAR), during experimental launches of LV Soyuz with Kick Stage Fregat and during launches of SC Cluster-II of ESA. During SC processing and flights a structural supervision unit is established within GD- Center for ballistic-navigation support, which takes part in operational SC ballistic-navigation support together with nominal Ballistic Center (BC) of Ground Control Complex. Orbit parameters estimation of SC flight in BC is performed with the minimum use GCC measuring devices, which provides its economic efficiency. Following are performances of BNS software newly developed by TsSKB for Foton SC flight pattern ballistic performances estimation, simulation and display in a quasi real time and results of Foton SC use in the Center of General Designer. Structure of SC BNS software for computing hardware of GD-Center of is presented in fig. 5. Structure of computing hardware for SC BNS is in fig.6. It is a segment of GD-Center local network and includes corresponding means of data exchange. Ballistic data are delivered to ESRANGE RS by Internet e-mail using mail servers of special Simple Mail Transfer protocol (SMTP). It provides minimum transfer time. An assigned channel with modems that provide transmission rate 33,6 Kbod is used as a technical transmission. Similar ballistic data are transmitted to Information Telemetry Center of GD- Center by telephone channels. Foton SC BNS software consists of two main special complexes: - package of applied ballistic tasks for: prediction of loworbital SC center of mass motion for various gravitational potential and atmosphere density modals configuration, estimation of wide range parameters for multi-impulse maneuvers, DV descent parameters, as well as for estimation of SC flight track, SC illumination, SC visibility zones, orbital elements, TD (Target Designation) for Ground Stations antennae targeting to SC; - software for SC flight pattern simulation displaying results in a real (quasi-real) time. Software has the following functions: - display cyclogram of pre-launch operations at the launch site according to the reports (fig.7); - simulate and display Soyuz LV with Foton SC flight trajectory and cyclogram in real time (accomplished operations are colored as the reports from the launch site, according to Soyuz LV TM analysis, are received, fig.8); - simulate and display estimated and actual (after SC motion parameters specified according to the trajectory measurement results are received) Foton SC flight pattern for the preset time interval ( up to 20 days, fig.9); - estimate Foton SC flight track and RVZ (Radio Visibility Zone) of involved CMS and RS for the specified time interval (fig.9); - simulate and display parameters of Foton SC braking maneuver, DV descent trajectory, DV landing point coordinates and estimated ellipse of dispersion (fig.10); present graphically Foton SC flight track, CMS and RS RVZ, landing areas, DV descent tracks and estimated ellipse of distortion in Mercator projection on the map (fig.11,12). Information and necessary explanations are given in Russian or English.
Results of Foton LV with Foton SC flight pattern simulation are usually displayed in three main windows: Flight Pattern, Track and Orbit, where there are auxiliary information windows with tables of current orbit RVZ, estimated and current Foton SC orbit parameters, parameters for DV deorbiting, weather conditions in the estimated landing point. The main window Flight Pattern dynamically changes in time process. At first it displays launch date and time, cyclogram of pre-lunch procedures and video of Soyuz LV with Foton SC launch (fig.7), then cyclogram of Foton SC injection to orbit by LV, estimated trajectory of LV active flight leg, where Soyuz LV position is marked in a blue color, current estimated center of mass coordinates and LV program pitch angle in the initial-launch coordinate system, as well as flight height (fig.8). Figures 8-12 present current Greenwich Mean Time (GMT) and Decree Moscow Time (DMT). In Flight Pattern window LV active leg is followed by Foton SC orbital leg for the specified time interval (fig.9), which end with simulation and display of Foton SC braking maneuver (fig.10). Orbital leg of Flight Pattern window is followed by descent vehicle landing area, where Russian Federation (RF) landing site and manned SC landing site situated on the Russian and Kazakhstan territory are showed (fig.11). At the preset time DV landing area is substituted by the scheme of search actions in DV landing site. It presents DV landing coordinates and pictogram of search devices: planes, helicopters and off-road vehicles. As soon as data on DV actual landing point is delivered to the window operator records angular and linear coordinates of DV actual landing point (fig.12). Foton SC flight track is simulated in the main Track window in Mercator projection (fig.9). Involved CMS and RVZ, Earth surface illumination are presented graphically on the map. In Orbit window (fig.10) three-dimensional picture of the Earth with a Foton SC orbits is displayed. The picture may be shown in various aspects. Flight Pattern and Orbit windows provide formation of a window to issue nominal and operational reports on SC operation, which are delivered from the launch site and flight control center. The main windows can be displayed on the screen simultaneously, if necessary (fig.9,10). Thus, BNS methods and devices developed by TsSKB and tested in nominal situations provide comfortable conditions for ballistic-navigation data usage to run scientific and technological experiments.
TABLE 1 - RECORD OF BALLISTIC INFORMATION EXCHANGE Structure of the OP array Structure of the RV window array 1 orbit number 22 number 6 month date 1999 year 20 hour 42 min time 2.557910e01 sec 4.704129e03 x projections of position -4.769867e03 y vector of the S/C 0.000000e00 z center of mass, km 1 orbit number 22 number 6 month RV window start 1999 year date 20 hour 59 min RV window start 2.732987?01 sec time 22 number 6 month RV window end 1999 year date 2.091872e00 V x projections of velocity 2.192816e00 V y vector of the S/C 6.851682e00 V z center of mass, km/sec 8.000000e-03 ballistic factor (S), m 3 /kg s 2 6.680119e03 major semiaxis (a), km 1.233435e-02 eccentricity (e) 6.282389e01 inclination (i), degree 1.757938e02 longitude of the ascending node (Ω), degree 1.041396e02 perigee argument (ω π ), degree 2.807388å02 true anomaly (ϑ), degree 9999 end of the array. Structure of the TD array 1 orbit number 2.288815?02 azimuth, degree 0.000000?00 elevation, degree the first step 1.659724?03 distance, km...... 9.668327e01 azimuth, degree 0.000000?00 elevation, degree the last step 1.714234e03 distance, km 9999 end of the array. 21 hour 6 min RV window end 3.706397?01 sec time...... 9999 end of the array. f_start.fot name file 22 number 6 month launch date 1999 year 20 hour 42 min actual lift-off time 2.557910?01 se? 22 number 6 month separation date 1999 year 20 hour 42 min actual separation 2.557910?01 se? time 9999 end of the array.