A "rover" has become a kind of catch-all phrase for wheeled vehicles designed to operate on the Moon. The first Lunar rover were used on the later Apollo missions. These were basically open, unpressurized, two-man affairs, more akin to the performance of golf carts than to the wheeled vehicles that operate on and off road on Earth.
Rovers will be an important part for any future exploration of the moon, and will be indispensable tools in the creation and maintenance of a permanent manned outpost on Earth’s natural satellite.
Two teleoperated rovers were already landed on the moon by the Soviet Union in the early 1970s. Called Lunokhods (Russian for "moon walker"), these two rovers and the accompanying Zond series of lunar flyby missions were completely overshadowed by the Apollo missions and are now only a footnote in the history of space exploration.
Still, the Lunokhod rovers displayed proof of concept, and were the distant ancestors of modern rover vehicles on other worlds, particularly the Spirit and Opportunity rovers currently deployed on Mars. Future teleoperated and semi-autonomous lunar rovers, which will be deployed for both exploration and to help construct a future moonbase, will take advantage of the decades of development that has gone into this technology.
Though they are likely to be employed in a large variety of roles, lunar rovers will have some features in common. First among these will be systems that will help adapt the vehicle to the ever-present hazard of lunar dust. Deposited over millions of years by tens of thousands of major impact events, lunar dust is ever-present over much of the surface and of a much finer, rougher grain than similar substances on Earth, making it more corrosive. Within hours of landing on the moon, the Apollo astronauts had much of their spacesuits and equipment covered with the stuff, and because of its abrasive nature it quickly started scratching camera lenses and degraded environmental seals. To deal with this dust, meticulously constructed environmental seals will have to cover all major systems and moving parts, and these would likely have to be repaired and/or replaced at regular intervals.
Also to deal with traction issues regarding the dust as well as the lesser gravity, wheels on lunar vehicles will be of a slightly different character than most used on Earth. Like the wheels on "dune buggies", they will have to be overly-large for the vehicle size, or have special patterns or flanges on the wheel rims to channel and push the dust out of the way.
There is also no free oxygen on the moon, meaning conventional combustion engines are unviable. Most rovers will have to use electrical motors, and most will have solar panels to aid with battery recharging whenever possible.
Teleoperations for these vehicles will probably at first be located at mission control back on Earth. In essence providing additional "crewmembers" to the initial lunar expeditions by remote. The on-site crew would also be equipped with the means to direct the rovers, but most likely that would be a rarity on early missions. However, as a manned presence on the Moon grows, teleoperations will likely expand to stations on landers and moonbases themselves to give astronauts better on-site capabilities. As robotics technology improves, so rovers with simplified or repetitive tasks, such as laying solar panels, would be made semi-autonomous, meaning they will be able to perform their functions with only minimal human oversight.
The teleoperated and semi-autonomous rovers will perform a wide variety of function. As such, they are also likely to come in many different sizes, makes and models tailored to their specialized tasks. These may include, but are not limited, to:
--exploration and mapping
--maintenance and repair
--solar cell laying
--mobile science instruments
In fact, if a moonbase ever becomes a reality, the rovers on-site will likely outnumber the actual human astronauts there for years afterward. A specialized lunar habitat, called a motorpool module, was discussed in the Moonbase Modules article. Basically, it has a small rover-sized airlock, designed to let the base’s teleoperated rovers enter to a large workspace where they can be repaired and modified as needed by the base personnel in a human-friendly environment without the need for EVA.
Lunar rovers developed so far have been open-frame vehicles. They required operators and passengers to wear pressure suits.
A pressurized lunar rover will offer astronauts what basically amounts to a small habitat module on wheels. Whereas the open-frame rovers would be intended for short excursions around a landing site or moonbase, a pressurized rover would be meant for longer trips that would be outside the smaller vehicle’s range. In other words, a pressurized rover would be the lunar equivalent of an RV.
The RV/motorhome comparison isn’t a random one; the pressurized rover will be intended to provide life support for its crew from at least several days to several weeks. It will need all the features of a habitat module--power, life-support, recycling, radiation protection, sanitary facilities, airlock, work stations, sleeping cots, and so on. This is in addition to motor, transmission, driver’s station, etc. Like with modern RVs, they will by necessity have to be showcases of compact design and space conservation.
Pressurized rover are likely to be used on lunar missions requiring the presence of, or at least the oversight of, humans. Maintenance, construction, excavation, and raw science work a good distance away from the moonbase come to mind, as well as moving personnel among different surface facilities that are too far away for a lunar walk but aren’t quite far enough away to justify using a fuel-guzzling hopper.
On any extended mission away from the moonbase, it is likely a pressurized rover won’t be sent out all by itself. One or more teleoperated or semi-autonomous rovers will probably accompany it anywhere it roams over the lunar surface. Some advanced pressurized rovers may even carry its own robotic rovers in specialized bays.
NASA’s John Mankins’ Habot scheme would use large pressurized rovers linked together to form a the basis of the first moonbase. Even if the Habot idea isn’t pursued, however, it might be a good idea to design most pressurized rovers so they could link together through their airlocks, either on their sides or rears. This way, rovers crews can more readily share supplies or swap personnel, and render assistance in certain emergencies, without the need for EVA.
One of a pressurized rover’s chief functions in the latter years of a manned presence on the Moon will likely to serve space tourists needs. They would act pretty much as one would expect, filling the roles of tour buses and excursion vehicles.
It is assumed that once a moonbase is fully operational, one of its chief industries will be ore mining and lunar dust processing. Factories and refineries will have to be set up on the moonbase, and once these are in place a means of moving the extracted ore to them in quantity will be needed. Enter a large rover dedicated to hauling many tons of such material over the surface of the Moon.
In many ways, lunar cargo haulers will resemble their terrestrial brethren--semi-, tanker, and flatbed trucks of various sizes and load capacities--in overall design. However, like all lunar vehicles, cargo haulers will need specially designed wheels and suspension to deal with what at times could be very uneven terrain, as well as intricately-sealed systems to deal with the ever-present hazard of lunar dust.
Most cargo haulers on the moon will likely be teleoperated or semi-autonomous, able to move to and from the mining site to the processing center with out the need for a human presence. However, at least some of the cargo haulers may be outfitted with pressurized life-support cabins to fulfill specialized purposes that would require a human presence.
Lunar cargo haulers will also probably be able to carry larger cargo beds, or even be hauling long trains of cargo trailers behind it, as the lighter lunar gravity would allow it to handle a larger loads for the same amount of engine output than their Earth equivalents.
One of the great natural treasures of the Moon is its vast stores of Helium-3, a valuable component of fusion reactions, locked up in its surface soil and rocks. Some estimates put the total available supply of Helium-3 on the moon at over 1.1 million metric tons, enough to supply the world’s current energy needs for thousands of years.
However, the Helium-3 is present in only trace amounts in any one sample of soil. Processing a million tons of lunar regolith, for example, would only yield about 70 tons of Helium-3.
Moving megatons of rocks for such a tiny yield--even as potentially valuable a yield as Helium-3--is economically inefficient. It would be better not to waste so much time and energy moving the rocks all the way to a centralized facility, and then hauling the waste away again. The solution is to build a vehicle that could be moved from mining site to mining site to do the mineral processing on the spot. It after all takes much less effort to move a single factory facility than millions of tons of material. The vehicle would process the ore, build up a store of Helium-3 in tanks, and then load those tanks onto cargo haulers once full.
These vehicles when first introduced probably would be about the size of a train locomotive or larger, evoking somewhat visions of the Jawa sand crawler from Star Wars. However, as the technology was refined, they’d become smaller and sleeker and more efficient, probably no larger than a typical cargo hauler.
Very advanced version may even be all-in-one mining and processing vehicles--cutting into the regolith, hauling it aboard, processing it, and filling Helium-3 tanks all in the same mobile package.
Like cargo hualers, most mobile ore processors would either be teleoperated or semi-autonomous, though a few might have pressurized life support cabins for specialized uses by humans.
"Mining the Moon" by Harrison H. Schmitt, Popular Mechanics, October 2004
On The Web:
http://ares.jsc.nasa.gov/HumanExplore/Exploration/EXLibrary/docs/ApolloCat/Part1/LRV.htmhttp://www.thespacereview.com/article/127/1 http://www.frc.ri.cmu.edu/projects/lri/ http://www.abo.fi/~mlindroo/Station/Slides/sld049c.htm