2
$\begingroup$

Already in 2011 NASA Ames Research Center proposed a Mars mission called Red Dragon that would use a Falcon Heavy.
A SpaceX 2015 estimation was 2,000-4,000 kg to the surface of Mars with a soft retropopulsive landing of a variant of the Dragon capsule.
So a small bulldozer could be used as a payload instead.

A bulldozer is a continuous tracked tractor equipped with a substantial metal plate (blade) used to push large quantities of soil or rubble. It could be equipped at the rear with a jackhammer to break up very hard earth or rock.

On Mars a robotic bulldozer could break up sedimentary rock and very hard soil with the jackhammer and then remove it with the blade.

In this way layer by layer of the subsurface could be investigated by a present rover, and with a much larger area then that of a hole drilled by a rover alone.

Of course the bulldozer would need much more energy storage capacity, more like that of an electric sports car, to do it's job. But it needs only to work for less than an hour a day because the present rover will have enough new material to investigate for the rest of the day.

So if the bulldozer has a 10 kW engine, it needs not more than 10 kWh energy a day.
A RTG that has 500 W power can deliver 12 kWh each day to the storage batteries.

So because much more information about the historic past of Mars can be obtained by breaking up and removing the subsurface, why not use the assistance of a bulldozer ?

It is believed that large quantities of water and carbon dioxide ices remain frozen within the regolith in the equatorial parts of Mars. An intelligent bulldozer could prove this believe to be true !

| improve this question | |
$\endgroup$
  • 5
    $\begingroup$ I don't see a question here @Conelisinspace, you seem to be making a statement instead. Are you asking if there are plans to send a bulldozer to Mars, or whether it's a good idea? $\endgroup$ – GdD Apr 4 '18 at 10:48
  • 4
    $\begingroup$ Agreed, no question here. What would power this Mars-dozer anyway? $\endgroup$ – Organic Marble Apr 4 '18 at 11:44
  • 1
    $\begingroup$ The question is if not much more could be discovered by removing the regolith and upper layers by a bulldozer. $\endgroup$ – Cornelisinspace Apr 4 '18 at 13:08
  • 2
    $\begingroup$ Drilling holes would probably be easier and even give you information about the crust's composition quicker. The only value I see for a bulldozer is in constructing something, not in science. Imagine the regolith turns out to be just a few centimeters thick where you end up and then you hit solid stone… $\endgroup$ – DarkDust Apr 4 '18 at 14:04
  • 2
    $\begingroup$ continuous tracks are rejected for reliability reasons $\endgroup$ – JCRM Apr 5 '18 at 9:38
7
$\begingroup$

Edit: added 4th bullet.

Mars exploration is not limited by how much dirt we can move quickly. It is limited by:

  • the necessity to understand what we're looking at, so we can make sense of the data we receive
  • the necessity to get data in the correct context, by working systematically: first understand the surface, then drill so we can see what's underneath
  • the need to do everything under remote control, with too much delay to be able to do it live, so everything the rover does has to be planned and scripted.
  • the need to sample locations that are some distance apart. Geology doesn't change 'quickly': if you take one sample, it's not necessary to take another sample right next to it. The rock may all be the same for a large area. So you use aerial photography to divide the terrain into zones that are geologically similar, and you take samples from each zone. There's no need to stripmine the zone.

A bulldozer would not be very useful. Ever tried using a shovel to scrape a thin layer of dirt off pavement? That doesn't work very well. A 2-ton bulldozer can't break rock, so its blade will scrape the surface of the regolith.

Let's look at the Bobcat E10, the first small excavator I found. It weighs 1 ton and has a 7 kW engine. To power it, you'd need either large solar panels, batteries and a charging station (which would limit the vehicle to a few days' driving range), or nuclear power.

Curiosity's RTG produces 100 W, you'd need 70 of them for a total weight of 3 tons. NASA is working on a higher-power nuclear source, but the Kilopower project is in a very early stage.

Running a 7 kW engine for 10 hours on batteries means a 70 kWh battery, and that's a few hundred kg (comparable to the batteries used in current electric cars). 70 kWh of solar panel isn't small either, so you'll quickly run out of weight budget.

| improve this answer | |
$\endgroup$
  • $\begingroup$ A bulldozer with a jackhammer can break rocky sediments and an excavator is not a bulldozer, I've used your calculations to edit my question. $\endgroup$ – Cornelisinspace Apr 5 '18 at 9:44
  • $\begingroup$ Two-ton bulldozers are rare (and for good reason: they depend on weight to get the necessary traction to move large amounts of soil). These small excavators usually have a dozer blade on one side. The arm is a good place to attach the jackhammer (which also needs power, by the way). $\endgroup$ – Hobbes Apr 5 '18 at 9:54
  • $\begingroup$ I have to agree with your 4th bullet and excavators look more suitable for going deep at one place. Seems a good idea to attach a jackhammer, they could work alternately.and the robot decides how much rubble it can take in one time. But they don't have to work for more than one hour a day, so couldn't you revise your energy calculations ? $\endgroup$ – Cornelisinspace Apr 5 '18 at 15:16
  • $\begingroup$ Excellent answer! #3 is slightly nuanced by the answers to How much can the Mars rover Curiosity do autonomously, after four years of operation? but further nuanced back in the opposite direction by Who discovered “Egg Rock”? The Curiosity rover or people? $\endgroup$ – uhoh Apr 7 '18 at 3:25
4
$\begingroup$

There are some issues I have with using an intelligent bulldozer for exploration work on Mars.

Firstly, a bulldozer would be heavy and thus expensive to get to Mars. We don't know how competent the regolith on Mars is in various locations. If the bulldozer isn't strong enough it will achieve little.

A bulldozer might work well if the top of the bedrock is relatively flat, but there may be issues if it is undulating or corrugated.

The other issue I have is that regolith is important too and it has a story to tell and significant data can be extracted from it. Clearing away regolith in bulk, without having properly investigating the regolith, is not a good exploration technique. Something significant may be destroyed and data lost or compromised.

| improve this answer | |
$\endgroup$
  • $\begingroup$ Thank you for your comment. A small bulldozer would not be that heavy. According to Wikipedia, regolith is a layer of loose deposits, so a bulldozer could handle that. Of course regolith is important to investigate so clearing away bit by bit would be a good technique.The rover is there for careful investigation.An intelligent bulldozer could be sensitive for much resistance of the bedrock so it could adapt to the undulation. $\endgroup$ – Cornelisinspace Apr 4 '18 at 13:48
  • 1
    $\begingroup$ A small and light bulldozer will not be powerful enough to remove the regolith. Weight is needed to get high friction to the ground and thus high force to move the regolith. $\endgroup$ – Uwe Apr 4 '18 at 14:12
  • $\begingroup$ @Uwe Yes, tests would be needed to determine the necessary weight of the bulldozer. But would 2,000-4,000 kg not be enough ? $\endgroup$ – Cornelisinspace Apr 4 '18 at 16:15
  • 1
    $\begingroup$ @Conelisinspace It could travel light, then pick up and load some boulders or gravel as ballast; the operational weight could be much larger than the payload weight. This is an interesting idea! $\endgroup$ – uhoh Apr 7 '18 at 3:19
  • $\begingroup$ @ Yes, this ballast idea is interesting, but now i think, according to one of the answers, an excavator with the aid of a jackhammer is more suitable for digging, for instance to look for the water and carbon dioxide ices within the regolith ! $\endgroup$ – Cornelisinspace Apr 7 '18 at 9:47
3
$\begingroup$

A bulldozer may be useful to remove large volumes of regolith. But to take samples from ground, you only need to drill a small hole. You don't need a bulldozer to do this, a rover equipped with a drill and may be a small shovel on a robotic arm will do. It is possible to take several samples in close or larger distances just as necessary.

On Earth geological surveys of a place to build a large building don't use a bulldozer to examine the ground, they use a drill to see what is below surface.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.