With North Korea’s long-range rocket test earlier this month and an expected U.S. effort to seek a tough response at the United Nations, concerns have grown that Pyongyang might conduct its third nuclear test. Satellite photos as recent as December 13 show that Pyongyang is determined to maintain a state of readiness at the Punggye-ri nuclear test site where a third test is expected even in the dead of winter. That effort includes a previously unidentified structure that may be intended to protect data gathering equipment from inclement weather. Despite flooding last summer and fall that destroyed key elements of the infrastructure at the site, the North moved quickly to restore their ability to operate the complex. Subsequent images from December show continued activity.