MARY LOUISE KELLY, HOST:
New satellite images taken just two days after the Trump-Kim summit indicate North Korea has begun rebuilding a long-range rocket site. The site is in Tongchang-ri on the country's west coast. North Korea started disassembling it last year, but it did not finish the job. And the new imagery shows cranes, a roof under construction and other signs of activity. Now, it is not exactly clear when the rebuilding started. Was it before the Hanoi summit or more recently - which prompted us to wonder, how closely is the U.S. able to monitor nuclear and missile sites in North Korea?
Jeffrey Lewis is director of the East Asia Nonproliferation Program at the Middlebury Institute of International Studies, and he's with us now. Hi there.
JEFFREY LEWIS: It's a pleasure.
KELLY: So a point to note, which is these new images come from commercial satellite technology - my first question is, who owns these commercial satellites? Who decides what they're photographing?
LEWIS: These satellites are owned by private companies, and so the private companies decide although they have clients. And in some cases, those clients are governments. The United States government buys a lot of commercial satellite images. But in other cases, the clients are places like my employer - academic institutions that study the spread of nuclear weapons.
KELLY: So help us understand the questions about timing.
LEWIS: So this is a function of the two different types of images we have. That really beautiful high-resolution image - that picture was taken after the summit. And that clearly showed that the facility was being reconstructed. What a lot of us have now done is go back and use the lower-resolution images. And what we can see is that in mid-February, things started to change at the site, but we didn't really know what the nature of that activity was until we got the much better pictures.
KELLY: Is satellite intelligence more important when monitoring North Korea than it might be with some of the other countries where the U.S. is trying to keep track of capabilities? Russia comes to mind or Pakistan. But in those countries, there are more readily available other sources of intelligence - human intelligence, old-fashioned spies on the ground.
LEWIS: I think that's exactly right. A country like North Korea is essentially closed. If you want to know whether a facility is operating, the only way you're going to be able to answer that is by looking at it from space.
KELLY: The limitation being of course that you can't see what is happening underground. So it takes you only so far if you're trying to look at their nuclear capabilities, for example.
LEWIS: So that's true, although we're hoping it's going to get less true. The commercial sector is moving away from just taking optical images and is starting to deploy different kinds of sensors. So we have a partnership with Airbus, where we get radar images, which in some cases, actually allows us to see through roofs. And then there are companies that take thermal pictures, so we can see if a building is warm.
KELLY: Wow.
LEWIS: There's a variety of new technologies coming online.
KELLY: Talk to me about the cat-and-mouse game. North Korea knows that the U.S. is watching from space. So when they wheel cranes to a site that they had said they were dismantling, they know it's going to be seen and remarked upon. This is North Korea signaling.
LEWIS: I think that's right. I mean, there is no chance that the United States was going to miss this development. And the way that the North Koreans had taken it apart, they didn't box things up and put them away. They laid them out, - right? - so that they could clearly be seen from space. And you know, I think the message they're trying to send is pretty obvious.
KELLY: And what is it?
LEWIS: So in his New Year's speech, Kim Jong Un said that if sanctions were not removed from North Korea that they would have to find a new way to secure the country's well-being. And so perhaps the next thing North Korea will do if negotiations really have faltered, as they seem to have, is it might start putting satellites into space using rockets. That's not a violation of his pledge to end missile testing, but I do think it will be fairly provocative and upsetting to a lot of people in Washington.
KELLY: Jeffrey Lewis - he tracks North Korea and all those satellite images of it from his post at the Middlebury Institute of International Studies at Monterey, Calif. Jeffrey Lewis, thank you.
LEWIS: It was a pleasure. Transcript provided by NPR, Copyright NPR.