There’s an enormous telescope at the South Pole. Measuring 32 feet in diameter, it’s the largest telescope dedicated to measuring cosmic microwave background radiation (CMB). The CMB consists of light particles left behind after the big bang, and astronomers can tell a lot about the evolution of the universe by measuring these cosmic microwaves. The South Pole Telescope (SPT) was designed specifically for this task.
You may be wondering why such an important telescope was built in one of the harshest environments on the planet. The sky is filled with moisture in the form of tiny droplets, like those that make clouds. When the air is cold, it can’t hold as many of these particles. Perhaps you’ve noticed that when you look at the night sky in the cold of winter, you see the moon and stars more clearly. Nowhere on Earth is colder than Antarctica, so it’s a perfect spot for setting up an enormous telescope.
Such a telescope still needs people to help operate and maintain it. The international team that supports the telescope is made up of people from all kinds of backgrounds and expertise, and due to the isolated nature of the job, they rotate collaboration members in to work there. Center for Astrophysical Surveys (CAPS) fellow Melanie Archipley has been studying SPT data since she began as a student, and she was given the opportunity to deploy to the telescope to supplement her work. Her advisor, and CAPS director, Joaquin Vieira, has been a member of the South Pole Telescope collaboration since his time as a student. He was a strong advocate for students interested in having the experience of working with the telescope and helped pique Archipley’s interest in going.
“It’s standard for many SPT collaboration members to have the chance to go to the South Pole,” Archipley says, “This telescope doesn’t have, for example, a full-time staff that would otherwise be manning the telescope, or maintaining it. Other sites around the world might have people like that.”
Archipley didn’t want to pass up such a unique opportunity when it came up. “Students doing their Ph.D. use the data but never go to the telescope,” she says. “I raised my hand in 2020 when I was in my third year, which is about when a student would go to the SPT if they were going to. But that was COVID. So that just did not happen. After a couple of years, I got my chance.”
Archipley flew down in late 2022, the summer for the southern hemisphere. Archipley had a lengthy stay in isolation, not unlike the isolation astronauts need to go into before they launch. “That was rough,” she said. “I spent two weeks in isolation due to COVID policies. And I thought that was the worst of it. But then I found out that I was going to be at McMurdo over Christmas. I hadn’t thought about it beforehand. It was an afterthought, this part of the process. But then you’re there, and there’s this whole town you couldn’t engage with, even friends I had made in Christchurch. It was just a lot of waiting because there was no work for me to do in McMurdo. It was a holding ground for people waiting to go to the South Pole. Then Christmas came around, and I couldn’t see my family. That was the lowest point for me.”
There was an upside to being isolated at a place like McMurdo station in Antarctica at Christmas. Because it’s so difficult and expensive to ship supplies to such a remote location, the price difference between lobster and peanut butter and jelly is negligible compared to the cost of getting it there.
“Christmas dinner at McMurdo was to the nines. Lobster and crab, and all these baked goods. Everything from the pastry chef was dangerous. I tried to limit myself to dessert only once a day. I told myself, you either pick lunch or dinner to get dessert. I did not stick to that at all because all the time it was amazing.”
Finally, with her isolation finished, it was time to go to the South Pole. When Archipley first arrived, the station was packed. The Admundson Scott station was at 98% capacity with nearly 150 people. The backlog of work that had to be done due to COVID delays kept the bustle going until winter approached. During the winter, Archipley says the station population drops to around 40. But this is also when some of the most important work is being done. Remember that the colder the skies, the better the view.
“We observe the sky during the summer, but our primary science happens during the winter due to contamination from the sun that happens in the summer. We are fully operating in the winter, just with fewer people. And we do SPT observations for the primary patch of the sky that we’re looking at. All the data that I’m using for my Ph.D. thesis, that’s taken during winter. We also do Event Horizon Telescope observations during the winter, where we fully switch out the secondary and tertiary mirrors and detectors to observe calibration sources for the black hole pictures that were very famous.”
Archipley’s days took on a specific cadence. Since she was in the South Pole, each day was very similar. “I would get up and first get coffee,” she said. “Because of the satellite internet schedule, we were limited in times when we could access the internet. The morning time during the summer was when the internet was up. If I had emails or work to check, or I wanted data from the north to work on that day, I had to get it early in the morning. My team would meet in the mornings to do our work that required internet access before lunch.”
Without internet access, Archipley busied herself with tasks around the station and work on the telescope. “I’d check in with the winter-overs and see what telescope tasks they wanted to do that day. I spent a lot of time in the beginning just trying to learn as much as I could from the winter-overs about how the telescope operated and its quirks. I wanted to learn the machine that I’ve been using data from all these years.”
Finally seeing the telescope in person was something of a dream for Archipley. “It was so magical to finally see the telescope,” she said. “It was just so cool to get a chance to be around it and see all of the weird things about how it moves, such as the power generation to make hundreds of tons of steel shift and to think about the real feat of engineering involved to create it. My background is in astrophysics. I’m studying the galaxies. It was a unique opportunity for me to get in touch with the engineering side of the telescope.”
While the telescope was the main reason Archipley made this trip, she got a lot of interesting opportunities to learn about how a station in such an isolated and harsh environment functions. She also ended up working on projects that connected back to UIUC.
“One thing that I got to help with that was really cool was the SPIDER recovery.” This spider isn’t the eight-legged creature you might be imagining. SPIDER is the name of an impressive balloon-borne instrument measuring primordial gravitational waves. The project has been running for almost a decade, and the most recent launch was headed up by Jeffrey Filippini, a UIUC physics and astronomy professor. “I got to watch the 2022 launch when I was at McMurdo,” Archipley said. “Then it came down while I was at the South Pole. The SPIDER team recovered all of the material, and then they needed volunteers to pack up hard drives, remove the trash pieces from the not trash, and bubblewrap these hard drives to send them back north. I spent a few afternoons doing that kind of work.”
Archipley learned some surprising things while at the South Pole. “Fire risk was a big deal,” she said. “Firefighters were very present all the time. There’s a whole team of them, and they are doing drills all the time, watching planes come and go. Because the station is literally just on kilometers of ice, it’s not grounded. That makes static electricity extremely dangerous. When a plane comes in, they use a spool of copper wire to ground the plane as best they can. Fire would be super dangerous because there’s no water.”
Archipley’s rotation wasn’t all work. When she wasn’t working on tasks or her Ph.D. thesis, she spent a lot of time with all the other people stationed there. They played cards and games to pass the time. They could work out in the on-site gym, and a popular location was the sauna. Her shifts were six days a week, but even with all she had to work on while there, she found time to run a half marathon for the first time.
“My favorite part about the experience was the telescope. But my second favorite was the South Pole Marathon. I was really stoked about it. It was an amazing challenge I gave myself. The altitude is basically twice the altitude of Denver. And the cold. A once-in-a-lifetime chance to do something like that. I was really very proud of myself and my team.”
When asked if she would recommend this work to others after her trip, Archipley wholeheartedly said yes, with a few caveats.
“You have to be in a certain place in your life to go. It’s really hard to stay connected to friends and family. When you’re down there, given the lack of internet and ways to communicate back home, you have to be of a mindset to handle it. You feel like you’re on another planet, you’re so separated. It really feels like a completely different life. But for people that have a couple of months where they’re thinking, where do I want to go next? Then you should definitely go because there’s nothing else like it. The experience in and of itself is amazing. The people who go down there are so unique and come from such different worlds and backgrounds. They make the experience like nothing else on earth.”
All photographs for this piece were taken and provided by Melanie Archipley unless otherwise noted.