Russian Vehicle Automated Rendezvous and Docking C Scott

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. merkle 1@jsc. nasa. gov

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

Russian AR&C System • Primary “Sensor” is Kurs Radar Antenna System – Long range (200 km 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) 3

Soyuz/Progress 4

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 • DV 1/DV 2 combination on orbits 4 and 5 is a maneuver to initiate the phasing rate • DV 3 on orbit 16 is a phasing adjust • DV 1 -DV 3 are ground targeted • DV 4/DV 5 combination on orbits 32 and 33 is an optimized intercept maneuver 5

Soyuz/Progress Rendezvous Profile In-plane view +Vbar ISS +XLVLH DV 5 @ 100 km OOP mnvr DV 3 DV 4 @ 400 km DV 1 DV 2 +Rbar +ZLVLH 6 Orbit Insertion

Soyuz/Progress Rendezvous Profile • AR&D nomenclature renames burns to Impulse 1 with DV 4 • 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 7

Soyuz/Progress Rendezvous Profile Out-of-plane view Impulse 1 (DV 4) +Vbar Impulse 2 (OOP mnvr) ISS +XLVLH +XOCK -Hbar +YLVLH +ZOCK Impulse 3 (DV 5) 8

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 9

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

Soyuz/Progress Rendezvous Profile In-plane view Berthing cone +Vbar ISS +XLVLH +XOCK 200 m 400 m +Rbar +ZLVLH -YOCK 11

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 12

5 P Docking Video 13

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 14

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 15

VIPe. R Attitude Constraints • • 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 4 R docking LVLH(0, -90, 180) +/- 15 deg acceptable through 3 A docking LVLH(0, 90, 180) +/-15 deg acceptable through Stage 6 A XPOP(0, 0, 0) +5/-15 deg acceptable through EATCS activation on 12 A. 1, i. e. 12 A. 1 docking • XPOP(0, 0, 180) +5/-15 deg acceptable through 3 A undocking 16

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 • Daylighting 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) 17

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 18

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. 19