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Mars Rover Perseverance Discussion Thread


cubinator
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2 hours ago, JoeSchmuckatelli said:

Okay - but when I watched 'The Martian'

they made weather on Mars look exciting.

 

Is Mars in Texas???

Well, now I see why Elon Musk moves to there.

Just was it necessary to bring the Martian weather as well?

 

Edited by kerbiloid
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So I nerded out yesterday evening and attemped to compute the hyperbolic trajectory that Perseverance followed to the entry interface. I used the data that was shown on mission control's readouts in the mission control livestream. I ended up having to make some simplifying assumptions but I arrived at an eccentricity of about 1.3 and a periapsis point about 130km below the Martian surface. The entry interface angle worked out to about 18 degrees. That's a bit steeper than the value of ~15 degrees that I heard quoted during the livestream. The data from the early part of the entry in the livestreams was still consistent with the vis-viva equation (i.e. aerobraking wasn't having a significant effect yet), so I don't think my numbers will be too far off. But it would be interesting to know the actual values. Anyone have any idea what they might have been?

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7 hours ago, tater said:

 

Next press conference is at 10:00 Pacific Time today. Hopefully they'll show them then?

 

Edited by PakledHostage
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25 minutes ago, PakledHostage said:

So I nerded out yesterday evening and attemped to compute the hyperbolic trajectory that Perseverance followed to the entry interface. I used the data that was shown on mission control's readouts in the mission control livestream. I ended up having to make some simplifying assumptions but I arrived at an eccentricity of about 1.3 and a periapsis point about 130km below the Martian surface. The entry interface angle worked out to about 18 degrees. That's a bit steeper than the value of ~15 degrees that I heard quoted during the livestream. The data from the early part of the entry in the livestreams was still consistent with the vis-viva equation (i.e. aerobraking wasn't having a significant effect yet), so I don't think my numbers will be too far off. But it would be interesting to know the actual values. Anyone have any idea what they might have been?

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Next press conference is at 10:00 Pacific Time today. Hopefully they'll show them then?

 

Wait - is there a video out already?  Your link is not yet live 

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1 hour ago, cubinator said:

When are we going to send a walker that can walk over the sand dunes and rough terrain instead of something with wheels?

Legs are slower, uses more power and is much less reliable than legs and even tracks. 
Benefit is that they handle rough terrain better. 

Robots are also not very agile negating lots of the benefits with legs, an cat has no problem with stairs but try to make an robot even with legs who handle something almost as tall as it. 

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Just now, magnemoe said:

Legs are slower, uses more power and is much less reliable than legs and even tracks. 
Benefit is that they handle rough terrain better. 

Robots are also not very agile negating lots of the benefits with legs, an cat has no problem with stairs but try to make an robot even with legs who handle something almost as tall as it. 

Quite true, however the robots are getting quite agile, I think it will be worth considering soon.

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1 minute ago, cubinator said:

Quite true, however the robots are getting quite agile, I think it will be worth considering soon.

Maybe. The military has already begun using robotic "dogs" for security on military air fields...

I suspect that before we begin using them on other worlds, unfortunately, there will be studies done to determine how they are able to handle the most inhospitable terrains and in unforgiving environments and situations on Earth, including combat roles.

As someone who teaches history at the university level, we often have a tendency to forget that it has always been the need for more advanced weaponry which catapults the scientific endeavors of humankind. Copper tools came about as flint knives and stone choppers were deemed as inferior weapons in combat. Copper gave way to bronze, bronze to iron, and iron to steel. And in each case, it was the need for weapons of war that catapulted the new technology into common use. By the success of copper weapons, copper sickles, copper fishing implements, and other copper based tools were developed until copper became commonly used. Then next, the development of bronze and so forth...

As robots become self-aware and can make self-preservation decisions, I suspect they will be utilized in space exploration and will become a powerful tool as we explore the solar system and other star systems in our galactic neighborhood. One of the problems with our current rovers is when they encounter something their programming isn't able to handle, they stop and are faced with a communications/instruction delay. Robots cannot simply "stand around" waiting for input as a wheeled rover can. If you watch the above video, there is still some obvious wobbliness in the design. The questions that must be answered are:

  • Can the robots handle extraterrestrial winds, such as the sustained winds on Mars (5 to 10 m/s or 11 to 22 mph) or Venus (80 to 100 m/s or 178 to 224 mph) ?
  • How will joints of the robot handle small and often microscopic debris, such as sands, blown into joints? Will the joints freeze up over time?
  • Would a "stand-by" mode involve some sort of squatting? What would be the long-term effects of frequent squats on the robot's joints?

There's probably many more questions which have to be asked before robots are sent out. I only mention those three because for my brain, those are the first ones which I thought of.

I'm sorry for the history lesson. It's what I do...

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8 minutes ago, adsii1970 said:

One of the problems with our current rovers is when they encounter something their programming isn't able to handle, they stop and are faced with a communications/instruction delay. Robots cannot simply "stand around" waiting for input as a wheeled rover can.

Well, autonomous mobility has been making leaps and bounds recently. Perseverance itself has software improvements that allow it to intelligently map terrain ahead and plan a course through it with minimal human intervention. And this sort of thing is already making its way into cars - you can already fall asleep at the wheel of your Tesla and the car will (probably) be able to handle it on its own.

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2 minutes ago, RealKerbal3x said:

Well, autonomous mobility has been making leaps and bounds recently. Perseverance itself has software improvements that allow it to intelligently map terrain ahead and plan a course through it with minimal human intervention. And this sort of thing is already making its way into cars - you can already fall asleep at the wheel of your Tesla and the car will (probably) be able to handle it on its own.

Not to the extent it would need to be for "legged" robots. And there's also the energy factor to consider. It takes less energy to make a wheel turn than it does to operate all the servos it takes to operate a robotic leg.

Do I see legged exploration robots in the future? Not for the next five years. But by the end of the decade, anything's possible...

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18 minutes ago, adsii1970 said:

I suspect that before we begin using them on other worlds, unfortunately, there will be studies done to determine how they are able to handle the most inhospitable terrains and in unforgiving environments and situations on Earth, including combat roles.

Oh I know what those robots are being designed for...I just hope they evolve empathy before they can commit themselves to such destructive endeavors.

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Haven't thoroughly searched, I admit, but do you know how far from the planned landing spot they actually got? Just curious.

Bet thy did better than me, last Duna landing about 350m from the targeted spot, and with KSP having scaled down 1:10, that would be 3.5km

Edited by VoidSquid
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3 minutes ago, VoidSquid said:

Haven't thoroughly searched, I admit, but do you know how far from the planned landing spot they actually got? Just curious.

Bet thy did better than me, last Duna landing about 350m from the ideal spot, and with KSP having scaled down 1:10, that would be 3.5km

They're 2 km from the delta's edge.

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