CHAPTER 15 SYSTEMS: ROBOTICS—THE CONSTRUCTION EQUIPMENT FOR THE INTERNATIONAL SPACE STATION 260 In 2004, the ground team uplinked approximately 3,500 commands to the MSS. This number is expected to rise to greater than 80,000 in 2018. Ground control does not employ hand controllers. Although the ROBOs could perform operations with hand controllers, the latency involved in issuing commands to the ISS via the Tracking and Data Relay Satellite System preclude them from performing the subtle motions required for operations using hand controllers. Therefore, personnel in the Mission Control do not “pilot” the arm like the crew does. Instead, flight controllers use pre-calculated, automatic sequences of instructions that tell each joint exactly how far to turn, at what rate, and in which order. During motion of the arm, the ROBO then monitors the system to verify it is executing the instructions correctly. These “ground control” operations use the various camera views available to Mission Control Center-Houston as well as computer depictions of where everything is in relation to each other, driven by real-time telemetry from the ISS, to provide in situ awareness for the flight controllers who are flying the arm. Crew, Houston, and Canadian Ground Control Working Together— A Case Study Another key capability of the arm is to capture visiting vehicles (see also Chapter 14)—a process that is performed symbiotically between the ground and crew, as illustrated by the example of the fifth H-II Transfer Vehicle (HTV) cargo mission to the ISS. On August 15, 2015, the Japan Aerospace Exploration Agency launched the HTV5 “Kounotori 5” resupply vehicle toward the ISS. Prior to the launch, flight controllers in Houston and Montreal attached the SSRMS to a PDGF on Node 2 and positioned it for the arrival of the visiting vehicle. After a couple days of free flight, HTV5 arrived underneath the space station and started slowly approaching the ISS on August 24 (Figure 14). Figure 14. HTV5 approaching the ISS from underneath in August 2015. Sunlight reflecting off shiny surfaces on the vehicle cause the starburst pattern. Over the course of a couple of hours, HTV5 moved closer to the ISS, orbiting just below the station (see “Are we there yet?” in Chapter 14). As the HTV moved closer, the crew on board the space station monitored the vehicle to verify it stayed within the approach corridor. The trajectory is designed such that HTV arrives at its station while keeping the position with its grapple fixture directly in front of the SSRMS LEE (Figure 15). From that point, the on-board crew members take over. They maneuver