DRAG0Nmon

Perseverance Rover Replica Challenge!

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Posted (edited)

With a historical launch this year of the Mars Perseverance Rover and the Ingenuity helicopter drone, space nerds have a lot to be excited for. To celebrate this momentous occasion, I'd like to see people's take on replicating this marvel of engineering in KSP. So the challenge is, Replicate the Mars 2020 Rover mission.

Rules: No cheating with debug menu or HyperEdit or anything related. DLC is fine, as is MechJeb (for info only), information mods, visual mods and TweakScale. I'll also be allowing Realism Overhaul as well RSS (Real Solar System) for those who want the added challenge of dealing with more Delta V requirements. No other part mods unless part of realism overhaul, and no other physics-altering mods other than RSS allowed.

How to win: Create a Duna rover (or Mars rover with RSS)  preferably resembling Perseverance, and a drone helicopter resembling Ingenuity (optional). Launch it on a rocket, preferably resembling an Atlas V, and land it on Duna (or Mars for RSS). OPTIONAL: Then, take your helicopter drone for a short flight and land it back on the red surface. Include a video of the mission or pictures of important parts of the mission.

Cant wait to see what you all come up with!

Also, if anyone wants to make a badge for this, I'll happily give them credit, as I am not much of an artist.

Good Luck!

 

Edited by DRAG0Nmon

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I'm interested. Just one thing - since this is generally for fun, what's wrong with using science related parts mods? For instance, Tarsier has a camera that fits this rover perfectly:

https://www.curseforge.com/kerbal/ksp-mods/tarsier-space-technology-continued

9CL3m22.png

Additionally, D-Magic has some of the experiments that are not included in the original or DLC content. I don't see how including these would make the challenge easier or unfair.

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@doggonemess The point is to try to create a stock replica of the rover, but since I allowed RSS, i figured I should just add Realism Overhaul since all those parts are designed and sized for RSS. That does look good though!

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Posted (edited)

Part of the reason for the limited interest might be that the difficulty curve feels kind of wonky. What I mean by that is that it's really easy to build something that kinda looks a bit like Perseverance, because KSP has a lot of similar looking stock / DLC parts built in. But for the parts that don't have decent stock look-alikes in KSP, building decent replicas of them gets really hard real quick. Especially if you don't (heavily over)use Tweakscale.

Take the wheels, for example. KSP of course has the Ruggedized Vehicular Wheels that look kinda similar to the ones on Perseverance, and if you just stick six of them on the rover, it'll look kinda like Perseverance from a distance. But if you try to actually recreate the rocker-bogie suspension and the cool-looking way the wheels attach to it… well, there just isn't anything like that in KSP, so about the only way would be to try to build the wheels and suspension yourself out of Breaking Ground robotics parts. Which might be doable, and making it work could actually be an interesting engineering challenge. But making it work and look authentic seems really hard. Especially if you want the rocker mechanism to actually work and tilt the rover body like it's supposed to.

Also, except for the Ingenuity drone helicopter, the Perseverance rover looks a lot like Curiosity. So I'd guess a lot of the people who might be interested in doing this have basically done it already.

Anyway, I figured the drone seemed kinda interesting, so I tried building a simple replica.

bJFCckz.png

Basically, what I wanted to test was whether I could hide the big ugly Breaking Ground rotors by clipping them inside the drone body. And it turns out I can. I'm kind of annoyed that I had to include a reaction wheel, but it was the only way I could get useful yaw control. In principle, it should be possible to control yaw just via differential throttle on the two rotors, but in practice stock KSP doesn't seem smart enough to do that. (Wouldn't be hard to write a kOS script to do it, though.)

And yes, it does fly. Not very long on just one battery, but then, neither does the real thing. :) Peak altitude on Duna is somewhere between 1.5 km and 2 km above datum, so better not land on a mountain. I could probably save a bit of weight and improve performance by reducing the motor size — 30% torque seems more than enough to max out the RPM limit even with a high blade pitch.

Edited by vyznev

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The rules were a little unclear, but do you have to make a replica or just a rover with a Duna/Mars helicopter. The rules say resembling, but how strongly does it have to resemble Perseverance.

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Posted (edited)

I would be really keen to have a go at this in RSS but will only do if Tweakscale is approved so I can mimic the mission more accurately.  Confirm Y/N.  

Edit:  Noted, it's in the OP as allowed so, Woohoo I am in!

An idea I had to make this more interesting is to mimic the sample collection with an ore container, and develop a second mission to collect the sample and return it to Earth.

Edited by jinnantonix

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Posted (edited)

Well this was fun, as my first rover mission I think it went well, I never had any interest in rover missions as I never saw the point in the stock game.

I tried to launch ingenuity as well, but came across a few issues which were taking a while to fix so didn't launch it.

This was on PS4 so no mods were used. I linked a video, the rover hits the Duna atmosphere at 5:36.  

 

Edited by MrThomnnus

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@catloaf I updated the rules so it isn't a requirement to resemble Perseverance

@MrThomnnus Excellent job! I like the use of a piston for the cables.

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Has anyone else seen @ShadowZones replica. Its... Big. That'll be hard to top without mods!

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This should help.

Here are some other mods I use for rovers:

and the breaking ground expansion.e

Ingenuity:

Adds Duna optimized rotor, however it's rotors are a little unrealistic an overpowered in comparison to the breaking ground ones.

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On 7/28/2020 at 1:15 AM, vyznev said:

Part of the reason for the limited interest might be that the difficulty curve feels kind of wonky. What I mean by that is that it's really easy to build something that kinda looks a bit like Perseverance, because KSP has a lot of similar looking stock / DLC parts built in. But for the parts that don't have decent stock look-alikes in KSP, building decent replicas of them gets really hard real quick. Especially if you don't (heavily over)use Tweakscale.

Take the wheels, for example. KSP of course has the Ruggedized Vehicular Wheels that look kinda similar to the ones on Perseverance, and if you just stick six of them on the rover, it'll look kinda like Perseverance from a distance. But if you try to actually recreate the rocker-bogie suspension and the cool-looking way the wheels attach to it… well, there just isn't anything like that in KSP, so about the only way would be to try to build the wheels and suspension yourself out of Breaking Ground robotics parts. Which might be doable, and making it work could actually be an interesting engineering challenge. But making it work and look authentic seems really hard. Especially if you want the rocker mechanism to actually work and tilt the rover body like it's supposed to.

Also, except for the Ingenuity drone helicopter, the Perseverance rover looks a lot like Curiosity. So I'd guess a lot of the people who might be interested in doing this have basically done it already.

Anyway, I figured the drone seemed kinda interesting, so I tried building a simple replica.

bJFCckz.png

Basically, what I wanted to test was whether I could hide the big ugly Breaking Ground rotors by clipping them inside the drone body. And it turns out I can. I'm kind of annoyed that I had to include a reaction wheel, but it was the only way I could get useful yaw control. In principle, it should be possible to control yaw just via differential throttle on the two rotors, but in practice stock KSP doesn't seem smart enough to do that. (Wouldn't be hard to write a kOS script to do it, though.)

And yes, it does fly. Not very long on just one battery, but then, neither does the real thing. :) Peak altitude on Duna is somewhere between 1.5 km and 2 km above datum, so better not land on a mountain. I could probably save a bit of weight and improve performance by reducing the motor size — 30% torque seems more than enough to max out the RPM limit even with a high blade pitch.

That is a great Ingenuity recreation!
I especially like the use of the antenna to hide the fact the blades are "hovering" above the body and the use of struts as landing gear.
I went with the small grip strips.

And yeah, flying is really only possible in the low atmospheric regions.
 

1 hour ago, catloaf said:

Has anyone else seen @ShadowZones replica. Its... Big. That'll be hard to top without mods!

Good thing I am not participating, then ;)

The size was something that came about due to the fact that there are no smaller parts than 0.625m ... Ingenuity's body is only 14cm in diameter and has a "wing span" of 120cm. With the smallest probe body I had to make Perseverance around it so large that then the fairing/head shield combo got big and then the cruise stage and then of course I ended up with a 120m Atlas V replica...

For the rover's wheels, I went with small rotors and the structural tubes. Luckily those were the size I needed them to be, but I think ruggedized wheels would have been roughly the same size but didn't nearly look as good.
 

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Posted (edited)

I would like to try launching ingenuity but having issues with the torque. Does anyone have any suggestions? I try videos but nothing seems to work.

 

Edited by MrThomnnus

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Hopefully the bumblebee rotor will be well sized enough to do a small ingenuity, however would be willing to have ingenuity off-scale and just do a kerbalized version, which is what I planned anyway. I can't find pictures, but it looks like the Duna blades are bumblebee scale, so they are probably even larger than the breaking ground ones.

8 hours ago, MrThomnnus said:

I would like to try launching ingenuity but having issues with the torque. Does anyone have any suggestions? I try videos but nothing seems to work.

 

Try messing with the blade pitch.

Yeah, I really didn't want to do it, but I think that tweak scale may be required even with mods. Oh well, if anyone here has modding skills it would be nice to have the smallest blades, rotors, probodyne qbe, smallest circular batteries and struts scaled down by a factor of 5.

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Posted (edited)

Below is my Ingenuity on Mars.  Flies brilliantly on Duna, but apparently in RSS, the Martian atmosphere is too thin for the stock parts.  Not surprising really, the Ingenuity IRL requires the blades to rotate at 2400 rpm, and for KSP the max is 460 rpm.  I tried hacking the part files, but can't find a way to increase the rpm or lift parameters.  Looks my RSS mission will not be including Ingenuity. :(

 

WIySdDh.png

Edited by jinnantonix

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4 hours ago, jinnantonix said:

Below is my Ingenuity on Mars.  Flies brilliantly on Duna, but apparently in RSS, the Martian atmosphere is too thin for the stock parts.  Not surprising really, the Ingenuity IRL requires the blades to rotate at 2400 rpm, and for KSP the max is 460 rpm.  I tried hacking the part files, but can't find a way to increase the rpm or lift parameters.  Looks my RSS mission will not be including Ingenuity. :(

 

WIySdDh.png

Use KAL-1000s to manipulate the RPM to go over the allowed maximum.

You can do the same with thrust level on engines, that leads to hilarious results, see Danny's video on Crew Dragon or his single stage to infinity.

Yes, you could consider it cheating... or just exploiting that the game allows you to do with the parts available.

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1 hour ago, ShadowZone said:

Use KAL-1000s to manipulate the RPM to go over the allowed maximum.

You can do the same with thrust level on engines, that leads to hilarious results, see Danny's video on Crew Dragon or his single stage to infinity.

Yes, you could consider it cheating... or just exploiting that the game allows you to do with the parts available.

But unlike thrust, 460 rpm is about the limit of the physics engine, so you may just discover a new kraken. Still, it should be entertaining

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13 hours ago, ShadowZone said:

Use KAL-1000s to manipulate the RPM to go over the allowed maximum.

I tried using the KAL-1000, but alas the RPM would not rise above 480, no matter what I did. What's more, the kraken awoke, eventually the blades would fly off in all directions.  Then I figured it out.  The Ingenuity is 2kg total mass IRL.  The answer was to mod the part config files, making the part mass roughly equivalent to real world.  Set torque = 5, and main throttle linked to RPM control.  Success!

22WUMvw.png

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Posted (edited)

Does anybody know the planned approach to Mars?  I have just completed the launch and transit, and now arriving at Mars, I have some options on how to do this.  I had been assuming that the craft simply entered the atmosphere and then lands directly, with a rather violent aerobrake from an entry speed of around 5600 m/s.  But i If I was NASA, I would choose for the craft to skim the upper atmosphere slowing down into a roughly circular orbit, then adjust to ensure more accurate positioning for the landing.  This has the advantage of placing less stress on the hear shield, with final entry speed of around 4100 m/s, however I am not sure if the cruise stage was designed to remain attached during aerobraking manoeuvres

mars2020cameras.jpg

Edited by jinnantonix

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No, the cruise stage is jettisoned before the vehicle enters Mars's atmosphere.

Tony Bela did an excellent infographic on the process:

 

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16 hours ago, ShadowZone said:

No, the cruise stage is jettisoned before the vehicle enters Mars's atmosphere.

Thanks, I will be assuming direct entry.

 

On 8/2/2020 at 1:01 PM, DRAG0Nmon said:

 

@MrThomnnus Excellent job! I like the use of a piston for the cables.

I tried using a piston, but it made the Descent stage and Rover assembly too tall.  Clipping it caused all kinds of unwanted explosions and disassembly during decoupling.  So I came up with another means of mimicking the cable lowering system on the descent stage

 

 

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Posted (edited)

Mars 2020 in Real Solar System. 

The emphasis is on dimensional accuracy, with all components similar in size, mass and performance to the real world (<+/-10% variance). 

 

 

Edited by jinnantonix

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On 7/28/2020 at 2:15 AM, vyznev said:

But if you try to actually recreate the rocker-bogie suspension and the cool-looking way the wheels attach to it… well, there just isn't anything like that in KSP, so about the only way would be to try to build the wheels and suspension yourself out of Breaking Ground robotics parts. Which might be doable, and making it work could actually be an interesting engineering challenge. But making it work and look authentic seems really hard. Especially if you want the rocker mechanism to actually work and tilt the rover body like it's supposed to.

So, after thinking about this a little, I decided to try building a rover with a working rocker-bogie suspension as a proof of concept:

VRPAB59.png

It's all built with BG robotics parts, no stock wheels. The only powered parts are the wheel rotors and the two servos at the front used for steering. (I believe Perseverance uses four wheel steering, but I was lazy and only made two of the six wheel steerable for this test rover.)

The real secret ingredient is the unpowered servo at the back of the rover body and the two grip pads attached to it, highlighted in the screenshot above. The grip pads have same-vessel interactions turned on, as do the four pads on the suspension that they're sandwiched between. What this simple mechanism does is implement the rocker part of the rocker-bogie suspension: it holds the pitch of the rover body at the average of the pitches of the two upper suspension arms on either side of it, thus allowing the body to match the approximate tilt of the terrain below it, even when said terrain is highly uneven:

NpTgRPu.png

Craft file here: https://pastebin.com/LV6crxNq

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17 minutes ago, vyznev said:

So, after thinking about this a little, I decided to try building a rover with a working rocker-bogie suspension as a proof of concept:

VRPAB59.png

It's all built with BG robotics parts, no stock wheels. The only powered parts are the wheel rotors and the two servos at the front used for steering. (I believe Perseverance uses four wheel steering, but I was lazy and only made two of the six wheel steerable for this test rover.)

The real secret ingredient is the unpowered servo at the back of the rover body and the two grip pads attached to it, highlighted in the screenshot above. The grip pads have same-vessel interactions turned on, as do the four pads on the suspension that they're sandwiched between. What this simple mechanism does is implement the rocker part of the rocker-bogie suspension: it holds the pitch of the rover body at the average of the pitches of the two upper suspension arms on either side of it, thus allowing the body to match the approximate tilt of the terrain below it, even when said terrain is highly uneven:

Looks good, I might try this myself using slightly different parts but with a similar concept.

How does the rover remain powered with six motors, are there batteries clipped into the main body?

 

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Posted (edited)
19 minutes ago, MrThomnnus said:

How does the rover remain powered with six motors, are there batteries clipped into the main body?

There's an RTG that you can see poking out of the rover body. The RoveMate body itself can store 120 units of power, so no separate batteries are needed. In practice, it seems that the BG motors are pretty power-efficient (and RTGs in KSP are, of course, unrealistically good). I've never noticed the stored charge dropping below max, even when running at top speed (which, for this particular rover, is around 7—10 m/s; beyond that the wheels start to get wonky), so apparently the single RTG is enough to satisfy their power draw.

Edited by vyznev

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