The Chandra X-ray telescope, now 25, offers a more “complete story of what the universe is doing”

On July 23, 1999, the Chandra X-Ray Observatory was launched into space aboard the shuttle Columbia, the first such mission to be commanded by a woman astronaut.

The Chandra telescope detects high-energy X-rays. In that way, it differs from the Hubble Space Telescope, which observes visible light, and the James Webb Space Telescope, which captures frequencies in the infrared range.

But NASA budget constraints could allow the mission to go dark in the coming years. To learn more about Chandra, Marketplace’s Meghan McCarty Carino spoke to its program manager, Megan Lin. The following is an edited transcript of their conversation.

Megan Lin: Chandra is unique in that it’s a telescope that collects X-ray data. So when NASA launched the Great Observatories program, it wanted to launch a satellite that could collect information in each part of the electromagnetic spectrum. So we’re used to looking up and seeing the amazing space that we can see with our eyes, but we’re only getting a small part of that story, there’s so much happening that we can’t see in the universe. So Chandra was designed to specifically look at X-rays, and X-rays that are emitted by objects in deep space. So that gives us information about some of the hottest and most energetic events that happen. So, for example, things like supernova, when a star explodes that releases a lot of X-ray, and we can learn a lot about that through studying it and looking at it with the Chandra X-Ray Observatory.

Meghan McCarty Carino: How has it contributed to science and our understanding of the universe?

Lin: Some of our greatest discoveries have been evidence that helped with the discovery of dark matter. And the fact that we’ve been a mission and have been observing for 25 years gives us a unique capability to observe objects multiple times and come back and revisit them years later. One of my favorite observations, we look at Cassiopeia. It was one of the first things Chandra observed, and we’ve gone back to it year after year. So what was a still image of what’s left over after a star exploded, we now have this video clip that you can see how the explosion has evolved over a human time scale, over 25 years, and we just learned so much from that and how the material moves and what the star was made of.

McCarty Carino: This launched 25 years ago this summer. Its launch was also historic, right? It was piloted by the first woman shuttle commander, Eileen M. Collins. Can you tell me more about its launch?

Lin: The launch too was historic in that Chandra, I believe, was one of the largest payloads ever launched from the space shuttle. So astronaut [Catherine] Coleman still lives in the area, and she comes and visits our team quite often. So she helped us to celebrate the 25th, and she was this payload specialist that helped to deploy Chandra out of the shuttle bay.

McCarty Carino: Now, as the program manager for Chandra, you have been at the helm maintaining and operating the X-ray telescope. What has that been like?

Lin: The day-to-day is interesting operating a spacecraft. You like when things are routine; routine means everything’s going well, but it’s still very exciting. I like to describe the job, it’s kind of like solving a giant puzzle to figure out what Chandra is going to do next week. So astronomers come up with these amazing ideas of things that they want to look up, that they want to observe in space, and we need to make those a reality. So you have all of these engineering constraints of what the vehicle can do, all of these science constraints of how you need to position the spacecraft to get the observation you’re after. And you assemble this really complex puzzle and then turn that into a series of software and code that the spacecraft understands, and then we can uplink that through the Deep Space Network, and we communicate with the spacecraft regularly to make sure that it’s doing what we expect, and to get all of that great science data down here and in the hands of the scientists.

McCarty Carino: I have to imagine that over 25 years, there’s been some wear and tear, some hiccups. I mean, this was a mission that was initially conceived to be only five years.

Lin: Yes, with a five-year prime mission, it’s amazing. We’ve gone 25 years, but I’m actually really impressed with how the spacecraft has held up. It is extended mission. It is aging. One of our main things on Chandra is as we get older, the material around the spacecraft gets darker, and it doesn’t reflect the light as much. So things get hotter on board, and that gives us more constraints that we have on the engineering side to maneuver the spacecraft, to keep all of the subsystems nice and cool while we’re taking these observations.

McCarty Carino: So what is the future of this mission? I understand the budget has been shrinking.

Lin: Well, I don’t know much about the budget, but in terms of the technical side of the spacecraft, I think Chandra has an amazing future ahead. Our team of engineers comes up with these amazing ideas to keep Chandra executing at its highest efficiencies and getting all of this great data. I mean, even just this year, we’ve seen the culmination of several major projects that have come together. So I mentioned that as things get hotter, it was becoming more restrictive for planning. But our propulsion team, they formed this working group. They got a number of people together from Northrop Grumman, from Smithsonian Astrophysical and from NASA, and they all put their heads together and brainstormed what ideas they could do to manage temperatures. And one of the restricting things was we have thrusters on board that get quite hot when we have to fire them. And they looked into, can we fire them hotter? Can we change the way we fire them? And it turns out they were able to do all of the above. So they looked back and pulled research from 1949, a study on the type of fuel we use, and justified using higher planning limits. They created a new flight software and new ground software to block hot thrusters and to update our firing algorithm to make it more efficient. And when they combine these things together, we got so much new capability on board Chandra. So we can now spend two times as long doing a single observation, which has just increased our efficiency and is giving us such great science return.

McCarty Carino: If this mission is eventually sort of sunsetted, what would that mean for science and astronomy?

Lin: I’m not sure for the big picture. I like to talk about what Chandra adds to the story right now. So when you see a lot of the photos in the media, I think we’re all used to seeing Hubble and James Webb photos coming down that are amazing, and we connect with those because they’re getting that visible information down. It’s what our eyes would see if we look. But if you look at the photo credit underneath that, you’ll often see a Chandra photo credit, or some of these other missions, because behind that they’re layering the X-ray data, and it’s just creating a more cohesive story, a complete story of what the universe is doing.

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NASA does plan to decrease funding in the coming years, effectively winding down the Chandra mission by 2029, according to a budget released in March. With limited resources, the agency plans to reallocate money to newer projects. Meanwhile, a grassroots effort is trying to drum up political support to save Chandra.