1. Russian Vehicle Automated Rendezvous and Docking C. Scott Merkle NASA Johnson Space Center Aeroscience and Flight Mechanics Division 5/22-23/2002, AR&C Working Group S. Merkle/281-483-2946 c.s.merkle1@jsc.nasa.gov

2. 2 Soyuz/Progress Rendezvous and Docking Profile Russian Vehicle & ISS Constraints Big Lesson Learned (M-34 Mir Collision)

3. 3 Russian AR&C System Primary “Sensor” is Kurs Radar Antenna System –Long range (200km to 200 meters) via omni-directional antennas Range, range rate, bearing –Short range (200 meters to dock) via active and passive fixed and gyro-stabilized scanning antennas. Range, range rate, relative attitude Data Management System –3 independent fault tolerant computers –IVHM system allows for pre-programmed aborts Docking Contact Conditions –Closing Translational Rate 0.2 m/s –Angular rates < 1 deg/sec –Lateral Misalignments < 0.3 m Manual Takeover –Soyuz pilot can take over rendezvous at any time during approach –Unmanned Progress can be remote piloted via TORU system (from 200 meters)

4. 4 Soyuz/Progress

5. 5 Soyuz/Progress Rendezvous Profile Soyuz/Progress use a 34 orbit rendezvous profile based on an initial phase angle of 240-330 degrees, culminating with nominal docking on Daily Orbit 2 of the third flight day Maneuver profile made up of three maneuvers consisting of five burns “DV#” nomenclature is that used by Ballistics DV1/DV2 combination on orbits 4 and 5 is a maneuver to initiate the phasing rate DV3 on orbit 16 is a phasing adjust DV1-DV3 are ground targeted DV4/DV5 combination on orbits 32 and 33 is an optimized intercept maneuver

6. 6 Soyuz/Progress Rendezvous Profile +Vbar +Rbar ISS DV5 @ 100 km DV4 @ 400km DV3 DV2 DV1 Orbit Insertion OOP mnvr In-plane view +X LVLH +Z LVLH

7. 7 Soyuz/Progress Rendezvous Profile AR&D nomenclature renames burns to Impulse 1 with DV4 Impulses 1-6 are calculated onboard Soyuz/Progress –Impulses 1-2 based on state vectors uplinked –Impulses 3-6 based on state vectors updated with Kurs data Offset targeting scheme allows Soyuz/Progress to pass by ISS safely if no burns are performed after the intercept maneuver Russians chose offset target out-of-plane (OOP) due to this axis having the smallest dispersions; initial offset is 1000 meters –Impulse 1 includes OOP rate null, driving planar crossing to 1/4 rev later –Impulse 2 is an OOP burn performed at/near planar crossing to drive OOP miss distance to desired range –Thus Impulse 3 (1/4 rev later) and target point at ISS altitude (3/4 rev later) occur at the OOP maximum

8. 8 Soyuz/Progress Rendezvous Profile +Vbar -Hbar ISS Impulse 3 (DV5) Impulse 1 (DV4) Impulse 2 (OOP mnvr) Out-of-plane view +X LVLH +Y LVLH +X OCK +Z OCK

9. 9 Soyuz/Progress Rendezvous Profile OOP direction (north or south) will always be the same as the sun side of the orbit, in order to keep the target (ISS) lit for visual monitoring Impulses 4-6 are braking burns which also remove the OOP component –Impulse 4 targets for 3/4 of the initial OOP offset –Impulses 5-6 target for 300 meters OOP At a range of 400 meters, AR&D software transitions to the flyaround mode, in which it begins looking for the Kurs directional antennas on the docking port –During this mode, the range is reduced to 200 meters A flag can be set that tells the software to approach to a nadir port or to an aft port if ISS is near LVLH (0,0,0), but capability maintained to go to a port at any ISS attitude

10. 10 Soyuz/Progress Rendezvous Profile +Rbar +Vbar ISS Impulse 5 Impulse 4 Impulse 6 In-plane view 200 m Impulse 4 Approach to aft port Approach to nadir port Impulse 5 Impulse 6

11. 11 Soyuz/Progress Rendezvous Profile +Rbar +Vbar ISS +X LVLH +X OCK +Z LVLH -Y OCK Berthing cone 400 m 200 m In-plane view

12. 12 Soyuz/Progress Rendezvous Profile Once aligned with the docking port, the Soyuz/Progress will stationkeep at a range of 120-200 meters until it receives the command to continue When this command is received, the Soyuz/Progress AR&D software begins the berthing mode Range/range rate profile results in ~8 minute final approach along the docking port, depending on initial stationkeeping range

13. 13 5P Docking Video

14. 14 Russian Kurs-related Constraints Pre-positioning of ISS solar arrays and radiators must be complete 100 minutes prior to the planned docking time in order to minimize blockage and multipathing of the Kurs signal In combination with array pre-positioning, the maneuver to the docking attitude must also be complete 100 minutes prior to the planned docking time This time was chosen by the Russians in order to complete these operations prior to the time the Soyuz/Progress Kurs attempts to lock on to the ISS Kurs

15. 15 Russian Communication Constraints Russian ground comm is required for docking because MCC-M is prime for decision-making (including aborts) for both Soyuz and Progress, and they need telemetry and visual monitoring insight into the docking process If a relay satellite were available, only video would be made available to the ground via transfer from ISS because Soyuz/Progress do not currently have the capability to interact directly with a relay satellite –Note that video with a data overlay is the only data being sent from Soyuz/Progress to ISS

16. 16 VIPeR Attitude Constraints ISS attitude constraints due to thermal limits on station system components. All attitudes are YPR sequence LVLH(0,0,0) +/- 15 deg acceptable through end of program LVLH(180,0,0) +/- 15 deg acceptable through end of program LVLH(0,-90,0) +/- 15 deg acceptable through 4R docking LVLH(0,-90,180) +/- 15 deg acceptable through 3A docking LVLH(0,90,180) +/-15 deg acceptable through Stage 6A XPOP(0,0,0) +5/-15 deg acceptable through EATCS activation on 12A.1, i.e. 12A.1 docking XPOP(0,0,180) +5/-15 deg acceptable through 3A undocking

17. 17 Russian Lighting Constraints Required for visual monitoring of nominal berthing and docking modes and contingency manual takeover Dependent on docking target design, spotlight and videocamera and periscope capability Daylight lighting options –The target is lit by direct sunlight, with the sun in a 70-degree half-angle cone centered on the docking target standoff cross axis, but only in the half of this cone such that the Soyuz/Progress will not shadow the target at close ranges –The target is lit by Earthshine of intensity 20,000-30,000 lux, and the Sun-Earth-ISS angle is less than 70 degrees (i.e. ISS is not near the terminator)

18. 18 Russian Lighting Constraints Night lighting requirements/options –In all cases the docking port and target are lit by the Soyuz/Progress headlight –All external USOS lights must be turned off –The Soyuz/Progress must have completed the flyaround mode and be in stationkeeping when entering orbital night (applies to Soyuz relocations as well) –Soyuz will stationkeep and begin final approach from 100 meters rather than 120-200 meters –Progress will stationkeep and begin final approach from 50-75 meters rather than 120-200 meters; more constrained than Soyuz due to more limited capabilities of the TV camera

19. 19 Progress M-34 Collision Progress M-34 Collision in 1997 –Russian goal was to save money by eliminating hard to find Kurs radar boxes. –Plan was to conduct dockings from 8 km using remote station pilot –Cause of collision was multiple factors Poor pre-mission planning Inadequate training for pilot and “safety” engineer. Lack of independent range/bearing check (Kurs system purposely turned off). Ground uplink of old state vector put Progress way outside expected manual handover point.