Goliath Awaits……… On Mars.
That’s what I would like to see the headlines read someday soon.

A long time ago, in a website far far away, I came up with a concept for a Mars Rover called Big Al. Perhaps the name wasn’t catchy enough. So I have decided to call it, Goliath. Compared to the other Martian robotic rovers it would truly be a Goliath. The size of a large SUV, Goliath would be able to carry out some serious research on Mars, especially finding a suitable site for a Martian Colony.

Goliath would be a very large rover, about the size of a Ford Expedition, with many capabilities far greater than anything we have sent, or anything we have planned. I envision the drive mechanism to be eight wheel drive, with individual electric motors for each wheel. For simplicity and reliability, it would be a skid-steer design or centrally articulated.

Goliath would be capable of taking core samples down to at least 30 feet and be able to analyze the contents of the cores in great detail on board. It would be able to set seismic transducers, create significant seismic vibrations, and record seismic waves. Goliath would also be able to traverse open ground at about 40mph, using AI and multiple sensors to move safely and autonomously across open areas of the surface of Mars.

When Goliath and others like him have identified a suitable site for a viable colony, He will send a signal to Earth: “Goliath Awaits the human colonists.”

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And what launch vehicle is going to get it there? Remember, you not only have to loft the rover, but also the landing system and the in-flight hardware.

Fred

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"For shame, gentlemen, pack your evidence a little better against another time."
-- John Dryden, "The Vindication of The Duke of Guise" 1684

Yeah, that name's going to capture imaginations: Goliath... that's the big fat ungodly looser that was stopped by a little stone, right?

Needs some marketing rehab.

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Ares V?

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Aim high (but don't blow yourself up)!- Homer Hickam

In Soviet Russia, UFO report you!- Phil Plait

Carl Sagan may have seen a pale blue dot, but I see a sapphire.- Doug Phillips, Discovering Alabama.

Clear skies Maksutov.

Payload on the Martian surface of the largest versions of Delta IV or Atlas V are of the order of 5 tonnes. That is exclusive of EDL systems.

Jon

I guess you never saw the movie Goliath Awaits Whatever. Anyhow, I was hoping for a discussion on the feasibility and utility of such a rover, not petty nitpicking at the name. Goliath, Big Al, Big Foot, Tiny, whatever………

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The name was only an interesting, significant fact when you commented on it. When I commented on it, it was nitpicking. Petty nitpicking, no less.

Any other peculiar restrictions to the direction we might take the conversation?

Got a backup plan for a headline?

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<chuckle>
entertaining you two

In the meantime...

I agree. I'm sure NASA agrees too. A buttkicking rover would definetly help and sadly, only size can deliver the power needed for hard travelling and core tapping.

The trouble with it is the energy conversion. The larger the rover- the more energy needed to power it.

Nuclear power, of course.

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Hmmmm...

What about maintainance? Such a large investment isn't something you want to wear out or run down too quickly.

Have it built by Checker Motors Corp.

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I doubt very much whether nuclear is going to be feasible for a vehicle of this size. Much better to use fuel cells, you should be able to get perhaps 1000 km out of a single filling. if you link in with a series of ISPP plants you can get effectively infinite range.

Jon

Using lasers to power craft has been discussed in other threads recently, so this makes me think that perhaps it would be possible to have a satellite in aresynchronos orbit that collects solar energy and then uses lasers to transmit power to the rover. This might sound like a lot of trouble, but it would save on weight that would need to be landed and the satellite could be used for later missions. If Spirit and Opportunity are still going when it arrives it could give them an energy boost when needed.

Laser beamed power doesn't scale down well. The mass and bulk of the focusing optics remain the same regardless of how much or how little power is being transmitted. It depends on the distance, and unfortunately geosync (or aresync) orbit is a terribly long distance. Beamed power from space works best when you either need a short burst of LOTS of power (laser thermal rocket launch), or you can afford a collection of power satellites. These can operate from low orbit.

Otherwise, plain old solar power works better. With Mars in particular, there's also the issue of dust storms. These may reduce solar powered vehicles to low power, but they would utterly block lasers.

For a mars ground probe, solar power is pretty hard to beat. The only really good alternative I see is indirect solar power--rocket fuel. You'd love to have a solar powered rocket fuel refinery to supply return missions launching from Mars. All the necessary ingredients are in the atmosphere, you just need the storage tanks and the solar powered refining hardware. As long as you've got this keen little fuel refinery with an endless supply of fuel...you might as well use it to fuel a ground vehicle also.

Still, that limits you to a particular radius from the fuel refinery. Excellent for in detail exploration of a limited area, but solar power is still the way to go for global surveys.

Thought that "Goliath Awaits" sounded familiar. Is that why you chose the name Goliath?...so you could make that little "word play"??

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"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

Yep.

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Reality: What a concept!……………………..><Ç(((Ç°>

I perfer the tagline for Zathura:
Adventure is waiting
So simple, and yet so powerful.

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I want to go back to the moon.
I don't care which rocket you use, whichever one you pick, I'll like it, I swear.
"If you think the LHC will create black holes, you might as well believe Hobbits are at the bottom of your garden."- Dr. Mike Inglis
Rovers forever! - ToSeek

So, can we get off the name game and actually discuss the practicality of large, SUV sized rovers for Mars?

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Honestly I like the idea of a larger number of smaller probes better. I think we really need to plop some probes onto the polar caps to find out what's there. Maybe even seed a large area with graphite dust to see if ideas for Martian terraforming based on melting the caps might work someday.

Imagine a radioisotope heated probe that can melt its way down through a polar cap. It can take readings all the way down to the bottom. This "ice digger" could be a precursor proving mission for a Europa ocean explorer. Wouldn't that be awesome? It's not just some embiggened Spirit/Opportunity. It's a new sort of probe, exploring a new part of Mars, and which could lead to an exotic explorer for the only extraterrestrial ocean we know of!

Note that the Martian polar caps may be the ideal place for a Martian colony, offering incredible amounts of easily available water. They might also be crucial for one day terraforming Mars.

For starters I would not have 64 kph as a requirement. You don't want to drive at that sort of speed cross country. Especially on Mars. Twenty kph would be more than enough. Remember with your sensor suite the rover is going to spend much of its time sitting still. Just as the current rovers do.

Also I would not have a seismic system on board. Deploying geophones is very labour intensive. I suggest a ground penetrating radar in a snake dragged behind. Or, if you except some inefficiencies, in a belly mounted anetenna.

Mind you, for the complexity and cost of such a mission for only a little bit more you could have a human crew which could do ten times as much. I know which I would prefer.

Jon

To both IsaacKyo's post and yours.
I agree and disagree.

IsacKuo, smaller probes would be beneficial and useful. So would would one big large fat one. Why not use both to fulfill all your needs?

Jon, although most of the sensor readings would be taken at a stand still, being able to move quickly to other targets and further targets can be an asset.

I agree with your statement about human interaction. Landing on Mars. However a probe can also stay longer and therefore do more during that time. Again. Given time and planning- maybe both are the most practical.

Money, money, money, must be funny, in a rich man's world.
- Old Swedish proverb

A rover would benefit from aerial survallience of the surrounding area of higher resolution than an orbiter could likely provide. I don't know if this idea is impractical or just plain stupid, but a camera that gets a few minutes flight using compressed martian air could be useful. But compressing that much air would take a fair bit of energy.

The improvement is surprisingly small. A rover is likely to spend about 90% of its time standing still, especially if ti is going to do detailed site investigations. This rule seems to hold true for both crewed and robotic rovers. Imagine a goliath rover doing a 100 km traverse. If it could travel at 10 kph it could cover this in 10 hours, 20 kph 5 hours, 50 kph 2 hours. But it isn't simply driving, it is working. let's stay it investigates 10 sites on the way, 10 hours at each, that's 100 hours. Total time to do the traverse at the afore mentioned speeds is 110, 105, and 102 hours respectively.

The faster you go, the more power you need, the more sophisticated the AI, and the more rugged the construction. These are extensive things to build into your rover. All four a saving of a few percent in overal time.

Furthermore if you are collecting data, say EM, GPR, magnetometer, gravity, spectrometry, etc. when driving you will want to move slowly, probably walking pace. You don't want your rover bouncing about, it upsets the instrumentation.

Note that 10 kph on Mars is the equivalent of 17 kph on earth, equivalent terrestrial speed increases by a factor of 1.7 for every 1 kph of speed. Note that 62 kph on Mars is the equivalent of 107 on Earth. I have done a lot of off road driving in remote areas, and the rule is slow and careful. Ground as rough as much of Mars I would not want to go over 20 kph on if it were on Earth. On Mars I would take it even slower.

I agree. These are not either-or choices. Note too that a crewed pressurised rover will carry at lot of built in instrumentation and have ample power reserve. It would almost certainly be capable of robotic operation and could do a lot of work before a human crew arrive and after they leave.

Jon

It's hard to imagine a case where more than 30 cm resolution of HiRISE is needed. But a tethered aerobot with a small camera might fill the gap.

Jon

IsaacKuo,
As we have seen, small rovers are extremely limited in what they can do. We need more than pictures samples of the surface to determine optimum sites for settlements. Only a large, robust rover with heavy equipment can do that.

While the polar caps may be a good source of water, they would definitely not be a good location for settlements. Remember, the solar energy that reaches Mars is about ½ of that that reaches Earth. Solar energy will probably be the main power source for Martian colonies, so optimizing the location for maximum exposure will be one of the criteria.

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Reality: What a concept!……………………..><Ç(((Ç°>

Remember, at 144,798,465 km², the surface of Mars is nearly the same as the land surface of the Earth (148,939,100 km²). That is a LOT of territory to cover, and much of it will be open country with few if any interesting (or at least important) features. If you surveyed one square kilometer ever day, it would take 39, 671 years to survey Mars.

All the more reason for high speed travel between testing sites.

Good suggestion. I will incorporate that into my design.

I disagree. A human mission would cost many times more. Humans are fragile, high maintenance machines that require frequent rests. And while they are self-replicating, the manufacturing cycle is quite long, and the new machines cannot perform useful work for many years and require even higher maintenance.

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Reality: What a concept!……………………..><Ç(((Ç°>

Manned missions to Mars are inevitable. IMO, they cannot begin too soon. However, it is very important to find the best settlement sites before the first humans arrive for several reasons. First, survival will be tough enough with a base to work from. Just getting everything set up and functioning will take up all of everyone’s time. There won’t be time to go looking for a suitable site.

Second, all the supplies required for the colony will have to be sent ahead. It would be impractical to build the colony anywhere other than where the supplies are landed, especially if the robotic cargo vessels are pre-fitted and used as habitats.

Third, without such a base to work from in the first place, manned missions would have to be round trip, which more than doubles the cost.

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An orbiter does not require much energy to operate once it is in orbit. Also, the platform is more stable than any flying vehicle. A sufficiently high resolution camera mounted on an orbiter could do the job.

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That is an unlikely scenario for the first large rovers. We know that there are great expanses on Mars that are essentially flat, open ground. The purpose of the rover will not be detailed examination of the entire surface, that will come much later when we have colonies there. The purpose of the initial rovers will be detailed examination of potential settlement sites. These will almost certainly be near mountains and ravines, not on open flats. So there will be no need for the rover to make all those stops along the way.

Again, due to the mission of the rovers, the savings in time will be great. As for construction, Goliath had better be built damn tough. Failure is not an option. And of course, it would travel at a speed compatible with the terrain (marrain?) Flat open desert

Huh?????

So have I. Hills, gullies, and rocks require slow and easy. Flat open desert is great for 80mph.

Check our your current vehicle. Most of the room and features are designed for the passengers. Having a rover that had to have food, water, air, interior room, and other features that humans need would either reduce the usefulness to half, or double the size.

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