It’s bad enough when something goes wrong with a complicated $ 2 billion physics experiment on Earth. These challenges are considerably greater when said physics experiment takes place on the International Space Station, orbiting 250 miles above the Earth’s surface. Thanks to the efforts of the intrepid ISS crew, who carried out a series of spacewalks to perform repairs, a damaged particle detector has been given new life.
Among the stars, a new six-part documentary series on Disney +, chronicles the challenges the crew faced on this mission over the course of two years. The series also chronicles the last space flight of veteran NASA astronaut Chris Cassidy, which occurred just as the COVID-19 pandemic was putting the world on lockdown. “Just kidding that three years ago I knew I was going to quarantine in March 2020 as planned,” Cassidy told Ars. “I just didn’t know the whole world would join me there.”
As we previously reported, the Alpha Magnetic Spectrometer (AMS) is a particle detector that was launched to the International Space Station in 2011 during the Space Shuttle’s penultimate flight. The machine has been collecting data regularly over the past six years, as it examines a variety of particles from many sources, including dark matter collisions.
Invented by Nobel Laureate (and AMS Principal Investigator) Samuel CC Ting, AMS consists of layers of smaller detectors and is designed to measure the energy and trajectory of cosmic ray particles, including high energy photons, electrons and positrons (antimatter of the electron partners). The instrument also contains a bank of high quality magnets that guide the path of electrically charged particles and help separate the contributions of different types of particles. The detectors allow researchers to distinguish between positrons and protons (which have an equal positive charge but different mass), electrons (which are negatively charged), and other particles.
In 2014, the AMS team announced the results of its first 18 months of data collection. They turned out to be frustratingly ambiguous. As Matthew Francis wrote for Ars at the time, “While the AMS-02 found an excess of a certain type of particle expected from some dark matter annihilation models, this excess did not carry characteristics predicted for a dark matter signature. So something interesting is going on in the AMS-02 data, but the chances of dark matter being the cause seem a little low. ” Still, physicists hoped that additional data collected at even higher energies could yield more conclusive results.
But then the experiment encountered a potential problem. In 2017, scientists monitoring the $ 2 billion AMS instrument noticed an increase in the “degradation” of several of the pumps that operate the thermal cooling system on its silicon tracker. Three of the four pumps had essentially failed. Only one is needed, but the cooling system had lost all its redundancy. Eventually, the fourth pump also showed signs of failure.
The physicists associated with the experiment therefore began to work with a team from NASA to design a long-term strategy that would extend the life of the AMS. They knew that installing a new group of pumps would require quite a bit of work, including removing the insulation. All of this required multiple spacewalks. ESA astronaut Luca Parmitano and NASA astronaut Andrew Morgan were the designated astronauts for the mission, with the help of NASA astronauts Christina Koch and Jessica Meir, who were responsible for operating the robotic arm. from inside the ISS.
Even though he was on Earth, filmmaker Ben Turner was on hand to capture everything on camera for posterity, including video diaries and live footage. The executive producer and director of Among the stars admits a long-standing obsession with spaceflight, and one of the highlights of his directorial career was filming a music video for One Direction at NASA. The experience whetted his appetite for more. “As a documentary maker, I have the ability to walk into cool places, tell the story of cool people and try to see the world through their eyes,” he said. “I had the ambition to do this with NASA for a long time.”
He got his chance when one of his business partners, James Corden (aka the voice of Peter Rabbit), was chatting with Peter Rabbit director Will Gluck on set. Gluck mentioned that he had met Cassidy. Knowing that Turner was a huge space fan, Corden put Gluck in touch with Turner for an introduction to the astronaut. Cassidy quickly got involved in the project.