Though details of the space plane are kept on a need-to-know basis by officials, it has been reported that the craft is carrying in its payload an Advanced Structurally-Embedded Thermal Spreader.
In August, the space plane was spotted by Marco Langbroek, a Netherlands-based satellite tracker. Langbroek previously told Space.com that X-37B was flying at a very low altitude, somewhere between 193 and 202 miles up.
— Dr Marco Langbroek (@Marco_Langbroek) August 20, 2018
"Basically, only one type of object fits this: X-37B," he said of the craft he observed. "Previous X-37B missions we tracked also orbited at such very low altitudes. The object also has a similar brightness to previous OTV missions."
Langbroek works alongside a small group that tracks the plane's path.
Although it's unclear where the OTV-5 will land once its mission comes to a close, website Space Flight Insider reported that it's likely to land at the Shuttle Landing Facility in Florida, the same location where OTV-4 touched down in May 2017.