There is just-in-time delivery, and there is just-in-time delivery.

In the middle of a battle, in the brief pauses between firefights, is a time to take stock of just what, exactly, makes the next hour more survivable. It could be everything from another case of ammunition for guns running low, a few gallons of water for people dehydrated by the heat and action of battle, a box of Meals-Ready-to-Eat. Without a means to get that cargo there, in time, and ideally without risking any further life in the process, the inventory of needs becomes an unfulfilled wishlist.

For the Navy, drones might just be the means to the last-mile delivery.

The Tactical Resupply Unmanned Aircraft System (TRUAS) competition challenged companies to develop a drone that could deliver at least 60 pounds of cargo to people at little over 6 miles away. This includes the above-mentioned water and MREs and ammunition, and anything else that a Marine company, platoon, or squad might need but be unable to retrieve on its own in a safe or timely manner.

To test the drones, the the Navy held a fly-off competition from Jan. 27-31 at Yuma Proving Ground in Arizona, focused on existing small drones. It is important that the drones not just be capable of delivering their cargo to Marines, but that they do so autonomously, without the need to occupy a human pilot for the duration of the mission.

A total of $225,000 was awarded from the competition. Of that, the $100,000 first place prize went to SURVICE Engineering, a company that has been turning hoverbike designs into logistics platforms for at least half a decade. Second place and $75,000 went to Chartis Federal, and Autonodyne took home $50,000 and third place. Also participating in the January competition were AirBuoyant, Bell Textron and Pacific Aerospace Consulting.

Next for the drones is determining requirements for prototypes, acquiring prototypes for testing, and possibly having the Marine Corps test the drones by fiscal year 2021. That is not a particularly fast clock for drone development in the commercial world, but it is a fair clip for military acquisitions, especially of devices based on so much commercial tech.

Watch one of the drones in action below:

Kelsey Atherton blogs about military technology for C4ISRNET, Fifth Domain, Defense News, and Military Times. He previously wrote for Popular Science, and also created, solicited, and edited content for a group blog on political science fiction and international security.