James Phillips (left) and Chad Cordill (right) use a roof bolting machine to secure with roof of the Sewell “R” coal mine in Yukon, W.Va.

An oil pump jack in a field adjacent to a sub-division near Fredrick, Colo.

Boeing and Lockheed Martin are developing a tanker drone, left, capable of refueling jet fighters in mid-flight.

This illustration made available by NASA on March 29, 2018 shows the twin Mars Cube One (MarCO) spacecraft flying over Mars with Earth and the sun in the distance. The MarCOs will be the first CubeSats – a kind of modular, mini-satellite – flown into deep space. They’re designed to fly along behind NASA’s InSight lander on its cruise to Mars.

FILE – In this Dec. 11, 2017 file photo, manatees swim with their calves at Blue Spring State Park in Orange City, Fla. According to Florida wildlife officials, there have been more manatee deaths so far in 2018 than all of last year. A total of 540 manatees have died through Aug. 12, whereas 538 died in 2017. Experts blame a cold snap at the beginning of the year and the toxic red tide algae in the Gulf of Mexico for the fatalities. About 100 deaths are blamed on red tide.