A hiker online asked me about when we might see a robotic "pack mule" to make long hikes easier. The big problem is energy (and noise) since right now the walking robots that exist use a lot of energy to travel, and most hikes involve some terrain you can't do on wheels.

He hoped for solar charging, but most hikers like to hike under cover away from the burning sun. The robot probably wants to be electric since nobody wants a loud engine on a pack robot on the trail. That's a problem.

For some, the idea of the pack robot goes against the self-sufficiency they seek hiking or camping. These ideas are not for you. If you like the idea of the hikes that have a series of stocked cabins spaced one day apart, you might be interested in what robots could do.

Flying drones

The first thing that came to mind was flying drones with a 25lb or so capacity. Near the end of your day's hike, you would find a suitable clearing on your map nearby, and summon the drone to it with as much of your overnight gear as it can carry. Sleeping pad, bag, light tent, fresh batteries, food etc. You would only have to carry your essentials, such as water, lunch, first aid, phone, emergency kit and whatever the drone can't handle.

In one mode the drone would stay there overnight, and fly the gear back to a charging station in the morning. The charging station could be on the grid, or it could just be a set of solar panels placed in suitable locations near the trail. The drone can wait there all day, charging. (There is an issue if it's a dark rainy day, though.) More likely, though, it flies to some station operated by a service, the same service that rented you this drone and maybe rents you the gear.

Another option would be for the drone to fly back empty to a grid or battery based station, then fly empty to you in the morning. That means more range, as such a drone will use a great deal less energy to fly unladen. This is less efficient on a total basis, though.

The drone could fly back to a service depot not just for an overnight charge, but it might even serve several campers if the trip is short. Since everybody wants to arrive at camp around the same time before sunset, and leave around the same time after sunrise, you can do this in a few different ways:

• You can only serve a small number of campers, depending on the distance to the campsites.
• With a more advanced drone, you can drop packages in clearings before campers get there, and definitely pick them up long after they leave. But that's a lot harder than having the human remove and attach the box on the drone. You must have no worries about theft.

Advanced ground robot

A ground robot could also do the trick of heading off unladen to get a recharge. With robot sensors, it can operate just fine in the night. It would need to be pretty silent if it will pass by other campers, which might not be easy.

The most efficient ground drone uses a combination of wheels and legs. There are a few designs which have legs with wheels on the end of them. When walking, they lock the rubber wheels and use them as feet. With all terrain wheels, such a robot could probably stay on wheels for a large portion of many trails, switching to leg mode only in the bush and over obstacles. With maps of the trails and your location it could even be slower than you in the bush and catch up on the flatter parts.

As long as the recharge stations are available and not too many miles from the campsites, it could get to them. Pure solar recharge is unlikely to work, but solar stations with batteries to handle the cloudy days could work. Another interesting option might be a small hydro generator that can be dropped into streams.

Reliability

The big issue of course, is can you depend on this system? What if weather, or breakdowns or other causes mean that the robot doesn't get your sleeping gear to you. Hopefully that's rare, and certainly rare without advance warning, but it's hard to make it impossible.

Some options then include:

• Emergency gear stations scattered in the territory. You may need to walk a couple of miles out of your way, even backtrack, but you could always get a sleeping bag and bivvy, dry food and water. They need to be monitored for theft.
• Not using this on hikes where you can't make your way to civilization in a day, including travel at night if need be, with what you carry on your back.
• Enough of an emergency kit on your back (space blanket, small sleeping sack) to handle an uncomfortable night, and not being more than a day away from return.
• A service that will come get you, or get gear to you, no matter what, and fully reliable radio/phone service to reach them.
• Not expecting to use such gear if severe weather is in the forecast, and not doing in places where the forecast might be that wrong. (ie. saying 100% good when in fact a severe storm could happen.)

The systems where a robot comes to you of course require a fully reliable communications network. Today many back country trails don't have that, but this will change with time.

The long hike in the future, for those who want the burden eased, will consist of a robotaxi ride to one trailhead, a hike with supplies delivered en route, and getting another robotaxi at a remote trailhead with no need to backtrack or loop.

Consequences

Of course, if you are going to have a service, why not just go back to the model of cabins spaced a day apart on the trail? Cabins are nicer to sleep in, but fix your schedule. Slower and faster hikers may not like them, and they often have to be booked long in advance. With robot delivery of your overnight kit, you can stop where you want, and there's no real limit on how many people can use the service, especially if you are willing to plan slightly in advance and aren't worried about theft.

Some would view this technology as a betrayal of what hiking is supposed to be about -- solitude and self-reliance. Even people who have highly resented the weight of their packs. Empty trails could become comparatively crowded. On the other hand, it would open up trails to people who otherwise would not be ready to hike them.

This will get even bigger if you combine this with "flying cars," which I have already written will have serious consequences as they give access to the wilderness to even the disabled and aged. They, and this, would allow anybody to hike even the most remote and difficult trail segments in the world. In the extreme, a hiker could be dropped off, hike, and sleep in a luxury hotel each night before being returned to the next good segment of the trail.