Mars hopper concept 'is feasible'

 
Hopper concept

A UK team is developing its idea for a Mars "hopper" - a robot that can bound across the surface of the Red Planet.

At the moment, landing missions use wheels to move around, but their progress can be stymied by sand-traps, steep slopes and boulder fields.

A hopper would simply leap across these obstacles to the next safest, flat surface.

The research group is led from Leicester University and the Astrium space company.

They propose the use of a vehicle powered by a radioisotope thermal rocket engine.

It would work like this: carbon dioxide would be extracted from the Martian air, compressed and liquefied.

Pumped into a chamber and exposed to the intense heat from a radioactive source, the CO2 would then explosively expand through a nozzle.

Calculations suggest the thrust achieved could enable a one-tonne craft to leap a distance of up to 900m at a time.

"The advantage of this approach is that you have the ability to traverse more aggressive terrains but also that you have wider mobility - the possibility of traversing much greater distances than we have with even the very successful rovers," says Hugo Williams, from Leicester's Space Research Centre.

Imagine jumping into and out of craters and canyons, and taking samples from locations that are separated perhaps by many tens of kilometres.

The team first proposed its concept hopper three years ago. Since then, it has been working to refine its ideas.

In particular, the researchers have been putting detail into how the gas compression system would work and how one might go about building the legs.

The latter are a critical aspect of the whole design. Legs on current planetary landers tend to use crushable honeycomb material to dampen the impact at the moment of touchdown.

That's great if you have no intention of moving again, but a hopper would need a resettable landing gear so that it could make multiple landings.

The team has been looking at a system that employs few moving parts and none of the hydraulic fluids found typically in Earth vehicles.

CAD Hopper

"It's a magnetic system that many people might recall from science lessons at school," explains Mike Williams, a mission systems engineer at Astrium.

"When you drop a magnet down a copper tube, you expect it to fall under gravity but it falls very slowly because, as the magnet drops, it creates eddy currents that generate an opposing magnetic field.

"Our legs would use this approach - a very simple, elegant solution that produces a damping effect.

"Nothing is crushed, and there are no fluids, which means we would be very insensitive to the environment and cold temperatures."

The latest phase of research has been funded by the European Space Agency (Esa).

It has sketched out the architecture for a 1,000kg hopper with a leg span of about 4m. The main body would be about 2.5m across.

At this scale, you should be able to carry at least 20kg of science instrumentation.

The study has also thrown up areas that need a lot more work. For example, the system that collects and compresses the CO2 takes several weeks to produce a usable volume of propellant. To be truly practical, the production process needs to be shortened considerably.

"Although we have identified some limitations with various technologies, I think we've demonstrated such a mission is feasible," says Mike Williams.

"Often with these very early and novel concepts, you can show quite quickly that they are totally infeasible. That's certainly not the case here."

Mount Sharp The current Curiosity rover is trying to reach a mountain but has to drive around a dangerous sandtrap

Whether we ever see a hopper sent to Mars is another matter.

To date, wheeled rovers and static landers have been doing a great job. And if we do decide to go with another form of locomotion, there are plenty of competing ideas out there, including planes, balloons and even "tumbleweed" devices that would be blown across the Martian landscape in the wind.

But it's the job of scientists and engineers to constantly look over the horizon. In that vein, you'll recall the space penetrator concept for landing on the Jovian moon Europa that I wrote about in July.

"Where the hopper study goes next is difficult to say," Hugo Williams tells me. "But it's important to remember that the reason we do this kind of research is not necessarily to define a single mission concept but to come up with technologies that can be spun out to many other types of space mission or indeed to applications here on Earth."

 
Jonathan Amos, Science correspondent Article written by Jonathan Amos Jonathan Amos Science correspondent

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  • rate this
    +1

    Comment number 256.

    @255.Robert Lucien,
    Something along the lines of NERVA is only required if you want a full blown nuclear thermal rocket.
    What would be far more viable would be a small reactor in the 10kw range(100kW for a manned earth return vehicle) to produce electricity to synthesize fuel over a longer period time and use that fuel in more powerful chemical rockets.

  • rate this
    0

    Comment number 255.

    #254 cont
    I'm not saying that this vehicle is impossible but I think they need to replace that RTG with a full reactor. NERVA attained 500 megawatts in a 10 ton engine way back in 1971. - So maybe 10 megawatts (rough round figure) in a reactor weighing 100 to 200 Kg could be possible today.
    Be great if it is possible though - BTW weight could be reduced by using the same engine to get to Mars.

  • rate this
    0

    Comment number 254.

    A few basic calculations. Assuming a basic acceleration of 6 m/s^2 on a 1 ton vehicle requires 6 kN of thrust. With an exhaust velocity of 3 km/s, est that uses 2 Kg of gas per second and requires 10 megawatts.
    A 10-12 second lift burst (+ 2nd burst to land) could attain a height of ~ 350 m, maybe allowing a sideways drift of 600-700 m.
    The energy required some is 200+ megaJoules - that's a lot.

  • rate this
    0

    Comment number 253.

    And if, after a leap, it landed on its back?

  • rate this
    0

    Comment number 252.

    Isn't it about time we started looking into exploring some of the more potentially interesting places such as Europa and Ganymede, to name but two? Why the heck are we still exploring a planet we already know quite well, when there are are other bodies out there of which we know very little about but, by their currently known constitution, could potentially be so much more enlightening?

  • rate this
    +1

    Comment number 251.

    231.bluzz123
    7 Hours ago
    Can't they used a legged robot instead?Wouldn't that be more energy efficient?

    +++

    If walking or running used less energy, kangaroos would not hop.

    --------

    Try hopping for a mile and then tell me how efficient it is whilst collapsing in exhaustion. A 6-legged spider like design is needed that can hop when required.

  • rate this
    +2

    Comment number 250.

    Sounds daft enough to work - great idea. I imagine the people who proposed using a hovering crane to put down a lander were greeted with incredulity and that worked out fine.

  • rate this
    0

    Comment number 249.

    @246.Robert Lucien,
    Which is why until there is an established human/industrial presence on Mars, the fuel for reusable launch vehicles on Mars should be derived entirely from the martian atmosphere which is largely oxygen and carbon in the form of CO2,.. and then nitrogen. This gives options of carbon-monoxide or cyanogen as fuels, and oxygen or dinitrogen-tetroxide as oxidisers.

  • rate this
    0

    Comment number 248.

    231.bluzz123
    7 Hours ago
    Can't they used a legged robot instead?Wouldn't that be more energy efficient?

    +++

    If walking or running used less energy, kangaroos would not hop.

  • rate this
    -1

    Comment number 247.

    Never ceases to amaze me why we don't send some lichen covered rock or grass seed into some of the deeper craters. If we have a human goal to move off Earth we need life to start or appear on the target planet. It is stupid to keep sending sterile stuff ~ lets get stuff to rust and rot and emit to see if we can get an atmosphere ~ else save the money and solve UK energy problems !

  • rate this
    0

    Comment number 246.

    #242 andyg, #239, etc

    Forget about my iron/ railgun suggestion, I just redid the calculations and its completely out. I had forgotten why I abandoned the idea in the first place.

    Re the solid material method : I was assuming a machine with a sample collection arm and an internal oven. That RTG will need to have a pulse power of at least ~1 megawatt and will have a lot of spare heat/power.

  • rate this
    0

    Comment number 245.

    Personally, I do not think that such movement is feesable, it will require much more advances to other parts/instruments to withstand it + mishaps. It adds many complications.

    Maybe other way is to have a mother ship that moves slowly, with smaller lighter/faster work drone(s), that return to mother to deposit findings & re-charge, as mother moves, drone(s) can comb large surrounding areas

  • rate this
    +5

    Comment number 244.

    Predictably here we have the usual narrow minded "spend it on solving the problems here first" mantra. Many of the worlds worst problems are due to religion. No amount of money will stop people believing in the supernatural, the only hope is through education, inspiration and logical thinking exactly what amazing science projects such as this encourage....

  • rate this
    +1

    Comment number 243.

    @241
    Or between NASA which is American and ESA which is the European Space agence and employs about 2000 people. Also this is in collabaration with Astrium that employs about 12,000 throughout Europe and ~3,000 in the UK. This is not just a couple of lone accademics.

  • rate this
    +1

    Comment number 242.

    @239.Robert Lucien,
    Regardless of whether you want to get the gases from the atmosphere or ground you're still going to have to compress them or liquify them depending on how you want to store them. Extra ground heating equipment is just going to add cost, weight and complexity, it is better to get your propellant entirely from the atmosphere, e.g CO/O2 or C2N2/O2 or C2N2/N2O4

  • rate this
    0

    Comment number 241.

    It's probably a good idea to differentiate between projects proposed by NASA, a multi-billion dollar enterprise that employs thousands of scientists and has put men on the moon, and those of Leicester University's Space Research Centre, whose website lists a staff of two!

  • rate this
    +1

    Comment number 240.

    How about, a rover the size of Curiousity (if it is not broken then don't fix it) but with hundreds of cheap expendable 2cm drones, like insects, to go and look around. Perhaps like grass hoppers or else fired out from the rover, high enough to glide down to sites a few km away.

    And perhaps they can fly back to the roving hive to refuel.

    This way all your eggs are not so much in one basket.

  • rate this
    -1

    Comment number 239.

    237.andyg

    I think you're forgetting how thin the Martian atmosphere is, that compressor will need a lot of power and time to work. I was merely hypothesising other methods of extracting gas or useable material that might be more efficient. Basically with a lot of rocks if you heat them enough they will emit CO2 and other gases.
    Admittedly the compressor is simpler and cheaper though.

  • rate this
    +1

    Comment number 238.

    Here's a list of life saving inventions that started with the statement "This is a waste of time and money, lets do something worthwhile instead

  • rate this
    +1

    Comment number 237.

    @236.Robert Lucien,
    I try to keep it real here,. as in producing fuel exclusively from the martian atmosphere. Even the Mars Direct plan would have brought a small amount of hydrogen with it in order to produce methane and oxygen from the martian atmosphere. Taking stuff out of the ground would require far more infrastructure. Also Mars has a low enough escape velocity for reusable SSTO vehicles

 

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