"I think the appropriate reaction is 'mild curiosity' rather than 'worry.'"
The Progress MS-07 spacecraft before launch. The mysterious sensor is the black object on the forward edge in the upper-right corner of the photo. Image: RKK Energia
A Russian spacecraft on a routine mission to the International Space Station (ISS) apparently carried a surprise payload: a secretive sensor that experts said could be related to a controversial military initiative.
The spacecraft, which the Russian space agency designated Progress MS-07, blasted off from the Baikonur Cosmodrome in southern Kazakhstan on October 12. The main mission of the unmanned Progress rockets is to haul supplies to the ISS.
After unloading the supplies, the station crew tosses its garbage into the now-empty Progress capsule. The craft separates from the station and, after a couple of days, tumbles back to Earth and burns up.
Russia often takes advantage of those extra couple of days to position small satellites or perform brief experiments unrelated to the space station. Progress MS-07, for example, carried a small data-relay satellite and a miniature robot that's part of a Russian company's social media campaign.
But Progress MS-07 also carried a mysterious sensor, one that might have important military implications. Anatoly Zak, an author and space expert, was among the first to notice the sensor in official photos provided by RKK Energia, the Russian company that manufactured the expendable Progress MS-07 spacecraft.
Russian officials told Zak that the sensor was part of a "one-time scientific experiment," but otherwise declined to comment on the device's purpose. The Russian space agency Roscosmos did not immediately respond to an email from Motherboard requesting comment.
The space agency is probably telling the truth about the sensor—just not the whole truth. "The device is mounted on a location used by other scientific sensors in the past," James Oberg, the author of several books about space technology, told me.
But what kind of science did the sensor support? After all, weapons-development is a kind of science. "The fact that they are not discussing it is unusual, and maybe it's a test of some military-related sensor of some kind," said Jonathan McDowell, an independent space expert.