Suggested Searches

Doug Caldwell Talks About the Data Pipeline for the TESS Mission

Season 1Apr 13, 2018

A conversation with Doug Caldwell, instrument scientist for the Kepler Space Telescope, and who’s now working on NASA’s next planet-hunting mission— the Transiting Exoplanet Survey Satellite or TESS.

Doug Caldwell

A conversation with Doug Caldwell, instrument scientist for the Kepler Space Telescope, and who’s now working on NASA’s next planet-hunting mission— the Transiting Exoplanet Survey Satellite or TESS.


Michele Johnson: (Host)You’re listening to NASA in Silicon Valley, a conversational podcast where we explore all the amazing work being done out of Ames Research Center. I’m Michele Johnson, filling in for Matt Buffington for this week’s 86th episode. Our guest today is Doug Caldwell, the instrument scientist for the Kepler Space Telescope, and who’s now working on NASA’s next planet-hunting mission— the Transiting Exoplanet Survey Satellite or TESS for the acronym inclined. TESS is launching early next week (Monday — April 16). Doug and his team will be standing by ready to examine the first data coming down from the new spacecraft. He’s helping to develop the software to process what we’re all hoping will be the next greatest hit, following Kepler, in exoplanet discoveries. With that in mind, let’s listen to our conversation with Doug Caldwell.

Michele: So, Doug, there’s a story behind everyone’s journey to NASA. How did you get here?

Doug Caldwell: It started a while ago when my fiance actually got a job out here after graduate school. And I came out looking for a job and had been applying for postdocs after I finished my astronomy degree. I actually got invited to a chocolate tasting by Jack Lissauer, who’s one of the co-investigators on the Kepler mission. We were just chatting and he was asking me, “What are you doing here? What are you doing?” I told him I was looking for a job and he said, “You should talk to this guy, Bill Borucki. He’s got this little telescope at Lick Observatory in San Jose nearby that he’s looking for people to help out with and help observe. I thought, “That sounds interesting. Something to do.”

So I talked to Bill, and he was keen to recruit people to help him out. And so I started working on this Vulcan Telescope, which was a small telescope, looking for planets around other stars. I started as an observer. And then I started working on the software to do the data analysis and helping to keep the instrument working and running. All this whole project was really sort of a testbed or prototype for the Kepler mission, which was being planned and proposed.

Host: This Project Vulcan, you said.

Doug Caldwell: Yeah.

Host: That’s an interesting name.

Doug Caldwell: Yeah, it was chosen not for Mr. Spock’s home world, but in the early 1900s people thought there was another planet on the other side of the sun sort of mirroring Mercury’s orbit, and it was called Planet Vulcan. And so, since our little telescope could only see big planets in short period orbits around their stars, we decided to name it after that planet.

Host: Fantastic. You mentioned Spock, too. I remember reading something about a Spock character in the story of Vulcan.

Doug Caldwell: Yeah, there was a Spock. I’m not sure if it as a he or she. It’s this very small dome that we got donated by the observatory that Bill and the team had to fix up and put in a new floor and fix the holes in the roof, and it was already inhabited by mice and other creatures. Mr. Spock was one of the little mice who ended up living inside one of our computers and chewing some of the cables and causing problems every few months of us having to go up and change out some hardware.

Host: So, we have chocolate so far, we have Vulcan, we have Spock the Mouse. Boy Doug, this is a very interesting start. What’s next?

Doug Caldwell: So what’s next was as this Vulcan Project was going on, the real goal, again, was to do this kind of search for planets. This was the science goal was to find planets ideally that could potentially be like the earth around other stars, to find out if they existed or not. Bill Borucki had this idea that he put forth in, I think, first in 1983 that you could do this from space with a telescope to observe stars. And so, the Kepler mission had been proposed to NASA to do this job several times, and I started helping to support the proposal that went in in 2000 and ultimately got accepted by NASA.

Host: Let me ask you, just in case people are just tuning in, what is Kepler?

Doug Caldwell: Kepler is a telescope that NASA launched with the goal of finding out whether planets, small like the Earth, are common or rare in our galaxy. And teaser, cut to the end, the answer is they’re common, and that’s what Kepler found. And so, that’s a really exciting fundamental science result that we didn’t know. Even 10 years ago we started to have inklings, but really, we know for sure now.

Host: Right, right.

Doug Caldwell: So my job, was to take the work we had done for Vulcan, which was a little, tiny ground-based telescope using a camera lens to look for these kinds of planets around other stars and show that what we had learned from there could help translate into operating Kepler, being able to observe lots of stars, analyze all the data, look at the results, find potential planets, and then follow up and decide if we really believe what we had found or not.

Host: A camera, tell us a little bit more about that and what that means, because this was early days of this technology. Right?

Doug Caldwell: Yeah, sort of. Kepler and Vulcan both are measuring the brightness of a star that they’re looking at, and they’re looking at a lot of stars. What they’re trying to find out is if a planet happens to pass in front of that star, as seen from us it’ll block part of the light from the star and the star will get a little bit dimmer.

Host: Okay.

Doug Caldwell:And so, the way we do that is we just take pictures of the stars. With Kepler, it’s every 30 minutes we take a picture and we downlink those pictures to the Earth, and we measure the brightness of each star in each picture, and we say, “Did it get a little bit dimmer?” And if the answer is yes, we say, “Okay, maybe that’s potentially a planet passing in front of it.

Host: And how much dimmer? What are we talking about, because these stars are pretty far away?

Doug Caldwell: The stars are far away. It turns out it ends up being it’s the fraction of the star that gets blocked by the planet. It’s the ratio of the area of the planet to the area of the star. So a big planet like Jupiter going around the Sun, Jupiter is about 1 percent the area of the sun, so it blocks about 1 percent or 1 part in a hundred of the Sun’s light.

Host: Okay.

Doug Caldwell: A small planet like the Earth is much smaller, obviously, and blocks only about 1 part in 12,000 of the Sun’s light. So, Earth going in front of a star like the Sun seen from far away would change the brightness of the star by 1 part in 12,000, or in Kepler-land, we like to measure things in parts per million.

Host: How many parts per million?

Doug Caldwell: Earth going in front of the Sun is 84 parts per million. So that means that if the Sun’s brightness is a million units, when the Earth goes in front of it – I have to do the math in my head now – it’s 999,916. It’s only a very little bit dimmer.

Host: Imagining all these numbers. Okay.

Doug Caldwell: Yeah, so the Sun is a big spotlight and you have something like a tiny little fly flying in front of it, and you’re trying not to see the fly but to measure, “That light got a little bit dimmer,” and that’s Kepler’s job.

Host: I heard an analogy once, like looking at a car, the headlight of a car the distance, a mile or 10 miles away, and a gnat crossing in front of it and being able to detect the change in brightness of that light.

Doug Caldwell: Yeah, so that’s what Kepler is doing. That’s a pretty good analogy. I’d have to measure the size of a gnat and a headlight to see if it’s exactly accurate, but you get the idea. it’s a very small change. And we have to do that for planets like the Earth, we only see this signal when the planet goes in front of its star.

And so, if we were looking at something that was – the system matched ours where you had an Earth orbiting in a 1-year period orbit, and that signal would only last about 12 or 13 hours. It takes about 12 or 13 hours for the Earth to cross the disc of the sun, and then you have to wait a whole year to see it again. So you have to see this very small change and be able to measure it over the scale of a year or 2 years or 3 years, and that was what Kepler was designed to do.

Host: But like our Sun, most stars are active and have star spots. Right? Don’t those also come into play and change the brightness of a star? How do you disentangle that?

Doug Caldwell: They do. Generally, the changes in the brightness of a star just by its natural star spots and as its magnetic cycles are changing are much bigger than this 84 parts per million. The 2 key things that really help us in looking for these signals – we call them transits when the planet goes in front of the star – that they are generally a fairly short timescale. Like I said, for Earth it’s about 12 or 13 hours. For a planet in closer, it can be an hour to a few hours. And on those timescales, stars are pretty stable.

And then the other thing that really helps us is we know that as planets are orbiting their star, they move according to Kepler’s laws, which is where we got the name. And so, they’re very periodic. And so, if we see a signal and then we see a comparable signal again in one year, that could easily just be two noisy things lining up. But if we see it again –

Host: 2 noisy thing?

Doug Caldwell: 2 star spots maybe, or just random fluctuations of the star.

Host: Okay.

Doug Caldwell:But if we see another one exactly the same time later, now we’ve seen 3 things that are periodic.

Host: 3 times the charm?

Doug Caldwell: 3 times is the charm, and 4 times, and 5 and 6 and 7 is really a super charm. And so, the more we see, the more confidence we have in being able to say, “This is really something orbiting around the star rather than just some change in the star,” which wouldn’t be as periodic.

Host: Now let’s go back to you and your specific role and being the instrument scientist. The instrument, the telescope, the part that you’re responsible for, tell us a little bit more about that and how those – Because as understand, it’s like what was in the early days of the digital camera, these lenses.

Doug Caldwell: Yeah, so as we mentioned earlier, the way we’re doing this, the way we’re measuring this brightness, is with a camera. It’s a digital camera. Kepler is a digital camera with 94 megapixels, 95 megapixels, 95 million pixels. It’s a big camera. Especially when it was originally designed and built in the early 2000s, it was very big. It’s taking a picture of the stars, as I said, every 30 minutes. And we just get this very boring picture of the stars. Once you’ve seen it, it’s kind of like, okay, those are the same stars you’ve been looking at for 4 years. But what we want to do is, again, measure this change in brightness.

So, the important thing about Kepler’s camera is that it’s very stable. We know how it behaves very well as it takes these pictures. It doesn’t introduce a lot of changes in brightness. It’s not moving around a lot on the sky. My job as Instrument Scientist, especially during the development and testing of the Kepler instrument, was to check that as we were building the instrument, this camera, and putting it together that it was really going to be able to do what we wanted it to do.

And so, Ball Aerospace is the company that built Kepler, and they had an excellent team that was putting this together and doing testing. My job was supporting them and trying to understand when we saw something during a test, was it okay? Was it going to still do what we wanted it to do scientifically. As you build any large complicated thing, things aren’t quite what you thought or you run into issues.

Host: And it’s something never before done. Right? You didn’t have a previous example that you could turn to and say, “Okay, this is what it means,” or, “This is what it should look like.” You and the team are kind of making this up as you go, or I should say learning as you went along.

Doug Caldwell: Yeah. There had been these digital cameras in use in astronomy and in other places for a while, but we were really trying a different use of it. We didn’t want to take really pretty pictures like Hubble does with high resolution and detail. We wanted to take a very stable picture over a long time.

Host: Right.

Doug Caldwell: And that was the question of how stable can this be. And so, that was what we were really testing.

Host: Because you were trying to measure that precision of the fluctuation in brightness.

Doug Caldwell: This very small change in brightness when the Earth goes in front of the Sun, yeah.

Host: So, the Kepler Space Telescope is still up in orbit collecting data, but as a new mission, K2. Now you as the Instrument Scientist, have you had to make any adjustments? What does that mean for a new mission, because it’s looking at new fields of view, it’s doing something entirely different than what the previous had done. What does that mean for your job?

Doug Caldwell: Yeah, one of the main parts of my job during Kepler was to make sure nothing changed. We really wanted this thing to be stable. “Put the instrument up there and don’t touch it, don’t change anything.” When we came to K2, it was like, “Okay, now we have to change everything.” And so, it was a big turnaround in our viewpoint of how we ran things. But we really wanted to optimize to make this instrument the best it could be in this new mission where it’s now pointing in a different direction every 90 days. We’re looking at a lot of different kinds of starts that we had been looking at in Kepler.

Host: Did you have to make any adjustments to the telescope, like the instrument itself then?

Doug Caldwell: We did, yeah. There were a lot of operational changes just to fly it in this new mode. I wasn’t so directly involved in them. But what we did have to do was in Kepler the telescope was very stable. And the main thing that changed was as it orbited the Sun the temperature would change slowly as the telescope went around the Sun. And that was one of our biggest sources of noise in the data of things that cause us problems in looking for planets. In K2, that change happens much faster and is larger. So, we end up having to remove more instrumental effects that show up in the data.

Host: What are instrumental effects?

Doug Caldwell: Two biggest are as the Sun moves around, the parts of the telescope that it’s hitting, the temperatures change and the focus of the telescope changes. And so, as the stars go in and out of focus, their brightness changes.

Host: Okay.

Doug Caldwell: It’s not changing because a planet is going in front of them. It’s changing because the telescope is changing. So we need to be able to remove that. The other big effect is that, again, as the telescope is changing its orientation with respect to the Sun, the electronics are getting warmer and cooler. Kepler’s fancy digital camera has some artifacts in its electronics that we learn to live with during Kepler, and now those are showing up. They’re strongly dependent on the temperature of the electronics. And so, we’re seeing those effects more prominently in K2. We also had to make some operational changes to allow us to look at different sets of stars with more or less pixels that we devote to each star.

Host: There’s a couple different ways of doing follow up and studying the stars and using ground-based telescopes, so those that are on the ground and looking up through the atmosphere of Earth and then those in space like Kepler. What’s it like to operate a telescope in space? From your vantage point as an Instrument Scientist, what are some of the challenges or opportunities that come along with being in space?

Doug Caldwell: Of course, the biggest challenge is you’ve built this thing and put it on a rocket and sent it away. So, you can’t touch it and you can’t tweak it, except to the extent that you can adjust things, parameters and how it operates, but you can’t change out resisters or anything like that. So that means you really have to be confident when you launch it that it’s going to work.

The real advantage is being in space really puts you in a different class of the kind of precision that you can do in these kind of measurements. We had been working on this Vulcan telescope, and other people had been doing ground-based searches for transits on the ground, looking through the atmosphere and the Sun is rising and setting.

Host: Right, okay.

Doug Caldwell: We had observed and other groups had observed a number of transiting planets before Kepler launched, a few tens, and they were seen from the ground. They were big, they were the size of Jupiter. We had all looked at them and understood. They’re very complicated and hard to get out of the data. When we launched Kepler, there was one of those transiting planets that was in the Kepler field of view. We knew that in advance.

I remember Kepler launched. We went through commissioning, which is basically checking out the instrument, making sure it’s going to work. And then we took 10 days of data that were supposed to be like the real science operation so we could check out our data analysis and that we could actually do this for real once we started up. We downlink those 10 days of data, and this known transiting planet was one of the targets we looked at, of course.

I remember a group of us were up in Building 244 here at NASA Ames sitting in front of the computer when these data came in. We quickly put together the measurement of these brightness of this one target, the light curve of this star for 10 days. Up until this point, we had built this instrument and tested it, and we were pretty confident that it was going to work. But everyone was sort of, “Well, it’s probably going to work.”

Host: This is the test. This is the truth. Right?

Doug Caldwell: And this is it. When we saw this light curve, this measurement of brightness from this one known transiting planet – HAT-P-7 it’s called – we were just stunned. The data were so beautiful. It looked like a model that people used to simulate these transiting planets, and we just couldn’t believe it. We saw the big drop in brightness, big, like one percent, drop in brightness. So that’s a thousand parts per million in Kepler-land.

Host: So Jupiter sized.

Doug Caldwell: Yeah, Jupiter sized.

Host: Okay.

Doug Caldwell: We saw this big drop in brightness as the planet went in front of its star. And then we looked a little more carefully. It’s a short period planet that orbits in three days, I think. At the halfway point, when the planet was going behind the star we saw another drop-in brightness. We sort of puzzled at that for a few seconds, and actually the discoverer had mentioned that this might be possible with Kepler.

We were seeing the light from the planet that when it went behind its star we no longer saw that light. The total system of star plus planet was a little bit brighter than just the star. And so, we were seeing the reflected light of this planet as it went away. The depth of that signal was about a hundred parts per million. When we saw that, we all knew, okay, this machine we built can do it, it can work, it can find Earth. So that was very exciting.

Host: Was that a fist bump, high five, or a hug moment?

Doug Caldwell: It definitely was, yeah. It was very exciting. We were just, “Ah.” Kind of relief and excitement. It’s like, “Okay, it worked. Good.”

Host: Yay. Wow, wow. We talked a lot about Kepler and K2, but there’s another mission coming up that you’ve also been working on, NASA’s next exoplanet hunting mission.

Doug Caldwell: Yeah.

Host: It’s launching in about, what, 13 days from today?

Doug Caldwell: It is 13 days, yes. Less than 2 weeks.

Host: So TESS, the TESS, Transiting Exoplanet Survey Satellite.

Doug Caldwell: Yes.

Host: Wow, so what’s your role on that?

Doug Caldwell: TESS, my role is working mainly on the data analysis end. The TESS Science Processing Operations Center, SPOC, another Spock, will be here at NASA Ames, and this is where it will get the data down from the spacecraft, take the pixels, the images, of all these stars, measure their brightnesses, and search through the measurements for transiting planets. And then ship the results out to the public and to the science team for further analysis at that point. So, my role in helping the SPOC here for tests is to work with the scientists and the pipeline development scientists.

Host: Pipeline development scientists?

Doug Caldwell: The software programmers who are building the data analysis pipeline. And try to make sure that they each understand what they’re doing and that the software they’re building does what the scientists want to do, and the scientists understand what they’re’ getting out of the pipeline.

Host: Right. Now this is a familiar pipeline though.

Doug Caldwell: It is very familiar. It’s based on the Kepler data analysis pipeline. TESS is a very different instrument than Kepler, but basically it’s the same thing. It’s a digital camera looking at stars, taking pictures and measuring the brightness. Once the data comes down, the formats are a little different, the numbers of stars are a little different, but it’s essentially the same goal. We want to measure the brightness of lots of stars, remove any effects that are caused by the instrument, and then search for planets.

Host: Did you work on the instrument part of TESS as well?

Doug Caldwell: I didn’t work on the instrument part of TESS. That was built at MIT. I’ve been trying to help to take some of the characteristics they’ve learned about the instrument testing and make sure that they’re in the pipeline for fixing them, for correcting them as we need to.

Host: Sure, sure. You said you’re working on the pipeline processing part, so getting the data ready so we can hand that off to the scientists and the public at large to go and play with and then search for planets. TESS is looking for planets in the same way that Kepler was looking for planets, but they’re a little bit different. They’re closer to home?

Doug Caldwell: It is different, yeah. Kepler was, during the main Kepler mission, looking at one patch of the sky at about 170,000 stars that it stared at for 4 years, the same set of stars. We were really looking for, ideally, planets that took about a year to go around their star that was like the Sun and were like the size of the Earth. What Kepler found – you shouldn’t forget about this – is that there are lots of planets out there. Basically, every star in the sky has planets.

Host: Yeah, it’s easy to forget. They’re so commonplace. Another planet discovery. Fantastic. Right? But really when you started on this, that was not it at all. There as a belief, but now there’s a knowing.

Doug Caldwell: Now there’s a knowing. And we also know not only are there more planets than stars in the sky, but there are a lot of planets that are small like the earth and potentially habitable, meaning they’re at about the right distance from their star where they’re at a comfortable temperature.

Host: Is that what TESS is looking for then? What kind of planets will TESS be looking for?

Doug Caldwell: Kepler found these planets far away, and now we know they’re there. And so, TESS is doing an all sky survey. It’s going to look at the entire sky and look at the nearest stars and try and find stars nearby us that have planets. We know planets are out there. Now we want to say, “Okay, they’re common. Does this star have one? Does this star have one?” TESS is going to make a catalogue of all the nearest stars.

Host: Why is that important? What is near important?

Doug Caldwell: Near is important because that lets you do a lot more science on the planet you find using other telescopes on the ground or in space. And so, NASA is launching the James Webb Space Telescope coming up soon. One of its goals is to be able to actually measure atmospheres of these planets.

Host: What are we measuring the atmospheres for?

Doug Caldwell: Ultimately we’d like to see if we can find indications of life in the atmosphere.

Host: Okay.

Doug Caldwell: We want to start by saying can we find things like water and carbon dioxide. Do they even have an atmosphere?

Host: Will TESS be able to do that? What will TESS tell us?

Doug Caldwell: TESS won’t measure atmospheres. But what it will do is it will find planets that James Webb will be able to measure the atmospheres of.

Host: Okay. All right. Great.

Doug Caldwell: So TESS’s goal is to find a number of targets the James Webb can follow up on, and also big telescopes on the ground can follow up on. It’s easier for a big telescope to learn a lot about a specific planet that’s nearby, but it’s hard for a big telescope to find a nearby planet when it has to look all over the sky. So TESS’s job is to find all these planets for further follow up.

Host: Okay. Wow. We mentioned earlier, launch is right around the corner, less than two weeks away. Is that something you’re heading out to?

Doug Caldwell: It is. I am going. I’m heading down there. My daughter, who is now twelve, has spring break that week. And so, we’re going to see the launch.

Host: Good job.

Doug Caldwell: She last was in Florida in 2009 for the Kepler launch when she was only five, or I guess four. She doesn’t really remember it. But it’s very exciting, and it’s going to be an interesting time. Kepler had a relatively sedate operations process. We would take data for 3 months and then downlink it and work on it. TESS is downlinking data every month on a new field of view. Kepler looked at the same field for 4 years, so we didn’t have to learn all these new stars. TESS, every month we’re going to have a new set of stars, and the speed of getting that processing done and out to the community is going to be much more intense.

Host: Okay. All right. How long does it take to get the data down? How long will it take to get the data down from the TESS spacecraft and turned over then for the scientific community to analyze? Are we talking months or is this weeks?

Doug Caldwell: TESS is orbiting the Earth, unlike Kepler which is orbiting the Sun, not the Earth. TESS is orbiting the Earth in about a 13-day period orbit, like half the Moon’s orbit. And every 13 days it downlinks the data and takes several hours, and then it collects another set of 13 days of data. You end up with about 27 days of data on one patch of the sky, and then it moves to a new part of the sky and you get 27 more days. The data come down at the end of the 27 days. The pipeline in recent testing, we’ve been seeing that the pipeline is working really fast. There have been improvements from Kepler.

Host: There’s a lot more data coming down, too. Right? TESS is really collecting a lot.

Doug Caldwell: There’s a lot more data coming down, and so we need to be faster.

Host: And in the order of a lot.

Doug Caldwell: A lot, yeah. A lot.

Host: Because there’s not as many stars. It’s something like 15,000 stars or so compared to Kepler’s 150,000, but it’s taking measurements every 10?

Doug Caldwell: It’s taking every 2 minutes unlike Kepler’s 30 minutes.

Host: Right.

Doug Caldwell: It’s also going to be taking what we call it in Kepler a full frame image, the whole sky, the whole field of its camera, every 20 minutes and downlinking that. And so, there’s a lot of data that’s coming out of TESS. Those full field, full frame images will be really useful for doing all kinds of science, because you can see things like supernovae going off in places you weren’t necessarily looking for planets.

And this 2-minute data from TESS of all these stars, will come down and be processed. We will search for planets in that and deliver that data to the archive. I think you asked the time for that. I think the official time is from the date the data gets down, we have 3 months to getting in the archive. We really expect to be able to do much faster than that.

Host: Fantastic.

Doug Caldwell:And then we have to be able to keep up. It’s 3 months, but then we have to be able to do that every month. But I think the timing looks like it’s probably going to be much quicker.

Host: That sounds very exciting.

Doug Caldwell: In the early days I’m sure we’ll see things in the data, they’ll be like, “Oh.” We’ll have to make changes in the pipeline, so we might want the full 3 months. But I think once we’re in operations we should be quicker.

Host: What’s the takeaway from TESS? What are we hoping to find or what’s TESS’s number one goal?

Doug Caldwell: It’s number one goal is to find something like 50 good targets for James Webb where good is a nearby planet that we have a size from TESS because we know how much light it blocked, and a mass from a ground-based follow up on it.

Host: Now are we talking about an Earth sized planet in an Earth-like orbit?

Doug Caldwell: It won’t be Earth-like orbits in the sense that when you orbit they’re closer because TESS is only looking at a patch of the sky for 27 days.

Host: Okay.

Doug Caldwell: Except one part of TESS, TESS has 4 cameras that are looking essentially from the horizon to the zenith straight up. As it rotates, it just moves that whole fan of cameras over 1 block and looks at the next part of the sky. But the camera that’s looking straight up is essentially just rotating around. So, the stars that are at the ecliptic poles, the north and south, will be observed for a full year. It looks for one year at the Southern Hemisphere and then it flips upside down – or right-side up, I guess – and then looks for one year at the Northern Hemisphere.

Host: I see. Wow.

Doug Caldwell: But the pole stars will be observed for longer so we can see longer period planets in those, and that’s also the James Webb continuous viewing zone. So those are good places for James Webb to look at things, too.

Host: Fantastic. Good. I guess you’re getting ready to pack your bags and head off to the space coast to see another launch. Do you remember these feelings from more than 9 years ago?

Doug Caldwell: Yeah, it’s been a while.

Host: Yeah.

Doug Caldwell: I do, definitely I do. It’s amazing. Any big project like this, years and years of work have gone into it before it ever starts taking the data, which is what we really want. Putting all that work on top of a rocket and launching it is kind of scary. I remember a number of us were down at the Kepler launch. Being there, it was a night launch, it was beautiful.

Host: I’ve seen the photos.

Doug Caldwell: It went up and you could see this amazing rocket going off into space and everything looked great and we were all very happy. But we were all a little bit edgy still because we knew that the rocket went up and went out of site, but did the spacecraft turn on. We had all prearranged to have a robocall at the time.

Host: Robocall?

Doug Caldwell: We had given the operations people our cellphone numbers, and they were going to send out a notice when they first heard back from Kepler. I forget the exact time, but I think it was about 45 minutes after launch when the spacecraft had been released from the rocket and powered on and it transmitted back the “I’m alive” message. We were all kind of celebrating but on edge a little bit. And then suddenly in this party’s cellphones rang at once, and everybody pulled out their cellphone and looks. It was, “Acquisition of signal,” and everyone is like, “Yay!” Kepler was alive. And then we could start working then.

Host: Now the work began after all those years of development and testing and making it through launch, the most dangerous part, and you had gotten the signal, it’s time to work.

Doug Caldwell: I’m confident TESS will have the same kind of success and it’ll be, I’m sure, very exciting too when know it’s up and working and we can really start getting this great data.

Host: That’s super fun. Wow. We talked a lot about a lot of things, Doug. Anything else you wanted to share and mention?

Doug Caldwell: I just think it’s just been really great to be on this project. I certainly feel very lucky that I got into this field of astronomy, in some ways stumbled into it, very early on and this exoplanet science, which didn’t exist in 1995 when I was in graduate school.

Host: That was the year of the first discovery.

Doug Caldwell: That was the year of the first discovery of an extrasolar planet. Not transiting, sorry. Extrasolar planet.

Host: Around a Sun-like star. Yeah.

Doug Caldwell: It’s around a Sun-like star. To now when it’s very well established. I think it’s very popular, it’s very exciting. We’re really answering a question that you don’t have to be a PhD in astronomy to understand why we might want to know this. Are we alone? Are there other Earths out there? We’re really taking a step towards doing that. And so, I’ve been really fortunate and happy that I could do some small part to help in that process.

Host: Fantastic, thank you. I think we’ll wrap it up for today then. If you have any questions, we’re at NASA Ames and we’re using #NASASiliconValley. Send us your questions and comments and we’ll get them to Doug and get back to you.

Also, we’re a NASA podcast, but we’re not the only NASA podcast. Don’t forget to check out Houston We Have a Podcast and Gravity Assist. The best way to hear all the NASA content is to subscribe to our omnibus RSS feed NASACast, or visit the NASA app.

Doug, thanks again for coming in. It was really fun to chat with you and I’m so excited that you’re working on this new mission and are going to be off to see another launch.

Doug Caldwell: You’re welcome, Michele, and thanks for having me.

Host: My pleasure.