The 10th annual Zero Robotics High School Finals took place January 27 onboard the International Space Station. Students from three countries uploaded their code to the ISS and watched a live webcast of Synchronized Position, Hold, Engage, Reorient Experimental Satellites (SPHERES) robots carrying out their programs in microgravity. This year’s challenge required the robots to attempt “hooking in space,” in the words of Dr. Alvar Saenz-Otero, who leads the Zero Robotics project and directs the MIT Space Systems Laboratory. The on-station referees for the tournament were NASA astronaut Anne McClain and Russian cosmonaut Oleg Kononenko.
SPHERES are floating soccer-ball-sized robots propelled by puffs of gas from small carbon dioxide canisters. Since they first got to the ISS in 2006, crew members have used SPHERES in more than 100 investigations. Some experiments use individual robots and some use multiple robots operating in sync.
This year’s Zero Robotics competition was the first experiment in which one robot attempted to hook and tow another robot. The robots were fitted with customized plastic hooks designed at MIT and 3D-printed onboard the ISS using the Made in Space Additive Manufacturing Facility! Installed on the ISS in 2013, this microgravity 3D printer has proven useful for producing custom components that the crew can use immediately.
This year’s challenge, ECO-SPHERES, deals with the growing hazard of space junk in low Earth orbit. To reduce the risk of collisions, researchers are testing several solutions for moving or destroying debris in orbit. Before the tournament got underway on Monday, engineer Hans Zachrau from Airbus spoke to student teams gathered at Kennedy Space Center. He discussed some of the solutions being developed for space debris removal, including RemoveDEBRIS, a refrigerator-sized spacecraft that shoots a net with weighted electromagnets around its edges that can capture and maneuver a target object. Here is the actual raw video of this technology being tested in low Earth orbit in 2018:
Apart from the net approach, debris can be removed by attaching to it and dragging it to a new location. That is the idea behind the hook-and-tow challenge in the competition.
This year’s challenge was extremely difficult. The students cannot control the SPHERES by remote control the way a hobbyist flies a drone quadcopter. The SPHERES carry out pre-programmed movements with limited ability to respond to unexpected changes. The programming all comes down to geometry and math.
In the challenge, the target is the red SPHERES robot, which floats helplessly in midair because debris has damaged its thrusters. The slightest bump will send it gliding away with no ability to correct its course. The player robot must approach the target from a distance, slow down at exactly the right time, rotate to align the hooks, and then change direction to tow the target toward the safe zone.
Add in dozens of impossible-to-control factors such as imperfect CO2 pressure in the SPHERES’ thrusters and variations in air currents within the station, and it’s not surprising that what worked in simulation did not work perfectly in real life. None of the teams fully succeeded in hooking the target robot. Only a few achieved hook-to-hook contact. But every partial success was a remarkable achievement for these high school teams!
Both of the winning alliances are groups of American and Italian students. First place went to Naughty Dark Spaghetti and second place went to Hit or Miss. Congratulations to all the participants!