"Doggy": high speed stock rover, sky-crane and carrier

[Warzouz]

"Doggy": high speed rover, sky-crane and carrier

(pictures are clickable - except this one...)

Doggy is a science probe rover which is designed be deployed on any planet or moon. Deployment is done with a specific skycrane : the Leash. Doggy comes by packs of 4 into the Pack Master which provide support and interplanetary transfer. Due to the number of PB-Nuke, the PackMaster is an expensive tool for exploring a body. Yet, it's nice and fun

Typical Doggy missions starts by setting the Pack Master into a polar orbit. From there, it can deploy Doggy rovers powered by their Leash. Deorbit and retro burn will land the Doggy. Then the Leash is undocked and Doggy is free to roam everywhere.

Doggy rover package
Download package : Doggy Pack (230kB)

• Doggy rover (subassembly)
• 4 Doggy rover with leashes (subassembly)
• 4 Leashed (subassembly)
• Pack Master unloaded (subassembly)
• Pack Master loaded (subassembly)
• 4 Doggy Packs (VAB ship)

Doggy, the rover
Doggy is a 1.1 ton rover equipped with rugged wheels for performance. It's full science probe with antenna and autonomous power supply. It's equipped with a reaction wheel for better control on low gravity bodies. Only rear wheels provide braking. Only forward wheels provide steering and motion. Doggy is powered by 2 RTG which let it run non stop. It can even send science while running. You may want to stop to recharge faster, but that's not mandatory.

Doggy has been tested on Kerbin for a 10m/s hard landing. Doggy has also been tested on Minmus, Duna, Mun, Eeloo, Eve, Laythe and Tylo. On Eve, it had landed on a 30° slope, and rolled to the bottom of the valley. On Laythe, highest speed on a 20° slope was reached at 55m/s, then braking has successfully slow down the rover. Let's say Doggy is very stable.

Doggy rover has also been tested on an extensive 550km trip on Eve at 20m/s on x3 physical timewarp without any crash. Also 30km trip on 5 to 20m/s on Mun (beware of ridges).

Important : remap WASD keys to numpad or arrows to allow control over roll, yaw and pitch using reaction wheel while jumping. This reduces flipping chances.

 
Unleashed Doggy front and back

Leash, the sky-crane
On the back of Doggy, there is a node designed to attach a sky-crane, a "Leash". Sky-cranes are used to land and deploy a Doggy rover. Leash is fitted with probe core, engine and/or chutes and heat shield. Leashes are not meant to be kept after landing. Decouple the leash and fire the engines, it'll go away and Doggy can run free.
There are 4 different Leashes

• Heavy Leash :  for Tylo, 2600m/s
• Medium Leash : for Vall, and Moho, 1510m/s
• Light Leash : for Duna and every other bodies, 730m/s.
• Atmospheric Leash : for Eve and Laythe (heat shield chutes and engines for 240m/s)

NB: the correct way to attach the crane is by having the OKTO2 logo toward the rear of the rover.

 

 
Light, Medium, Heavy and Atmospheric Leashes (on Doggy)

Pack Master, the polar orbital carrier
Pack Master is the Doggy carrier. It hosts 4 Doggies with their Leash. The carrier is equipped with a probe core, and non reusable science equipment. It's provided without engines, You only have to get a proper engine and fuel tanks to make it to your destination.

Pack Master configurations (without interplanetary stage) :

• Loaded Heavy Pack Master is 221 parts for 21.6T
• Loaded Medium Pack Master is 189 parts for 12.8T
• Loaded Light Pack Master is 181 parts for 10.1T
• Loaded Atmospheric Pack Master is 197 parts for 16.2T (instead of 300 parts!)

Pack Master loaded with Aero Leashed Doggies and with Medium Leashed Doggies

Flight operations

• Set the Pack Master on a polar orbit
• Use Pack Master material lab and Goo in high space and low space.
• Decouple the rovers one by one.
• Control from the probe core on the sky-crane and deorbit.
• For vacuum worlds and Duna, just do a regular retrograde landing.
• For atmospheric worlds (Eve and Laythe), set the rover prograde after deorbiting. To Avoid burning the wheels, roll the rover. When speed is safe, detach the heat shield and shake it loose. Head retrograde and trigger chutes.
• Always keep a bit of fuel to get rid of the crane.
• Lock brakes before landing. Activate lighting and control from frontal probe core.
• After landing, decouple the Leash and lift it, then go sideways (you may free engine gimbal).
• You can use the rover freely.
• SAS is not mandatory but it makes driving much easier, especially on low gravity worlds.
• On low gravity worlds, steer using SAS. On high gravity worlds, steer with the steering controls.
• When braking, you can also go backward and pitch up a bit to help wheel touch the ground.
• When jumping, use SAS to land parallel to the ground.
• When climbing, you can hit “6” to go to 4WD. That use more power but helps. Turn it down when you don't need it
• Have fun

 
Eve atmospheric reentry and rolling from a 30° mountain
 
Laythe speed record (55m/s on 22° slope) and Mun crater jump

Action groups

• 6 : Toggle 4WD
• 8 : Instant science
• 10 : Deploy antenna (cosmetic)

 

Feedback appreciated

Edited March 21, 2016 by Warzouz

[Majorjim!]

Very cute, and great craft presentation mate. Kudos! Can we have a 'puppy' version too?

[Warzouz]

37 minutes ago, Majorjim said:

Very cute, and great craft presentation mate. Kudos! Can we have a 'puppy' version too?

The puppy would have been the prototype

Edited March 19, 2016 by Warzouz

[Warzouz]

Well, after building the pack master with atmospheric sky-cranes, the ship (even incomplete) is about 300 parts. I think I've to simplify things...

 

EDIT : Crate Jumping (click to enlarge) any flying boulder

Edited March 20, 2016 by Warzouz

[Warzouz]

OK, the Doggy Pack is available.

I've doing some serious tweaking

• Rover : removed dorsal docking port and replaced by cubic strut
• Rover : Science are all individual (no symmetry). Action group 8 activate all 7 science experiments now.
• Rover : Lot of tweaking to get COM right on the cubic strut
• Rover : Wheels lowered to get better ground clearance
• Leash : Part reduction (removed secondary reaction wheel and some cubic struts)
• Atmospheric Leash : Only one heat shield, 2 big chutes instead of 7, most cubic struts removed.
• Pack Master:  Girders replaced by structural fuselage (nicer, simple lighter)

With those upgrades :

• Loaded Heavy Pack Master is 221 parts for 21.6T
• Loaded Medium Pack Master is 189 parts for 12.8T
• Loaded Light Pack Master is 181 parts for 10.1T
• Loaded Atmospheric Pack Master is 197 parts for 16.2T (instead of 300 parts!)

Of course you need a proper interplanetary stage.

EDIT : First topic revamped

Edited March 20, 2016 by Warzouz

[Warzouz]

I'm currently attempting a nightly 550km trip on Eve at 20m/s speed on x3 physical time warp using MechJeb Rover Autopilot.

EDIT : after more than one hour and 250km done, everything goes smoothly. I've tried to go to x4, but the rover blow every 30km. On the other hand, I'm testing with the previous prototype. The published version has a higher ground clearance. It could work at x4.

EDIT 2 : 560km done. I meet with the latest version of the rover which has higher ground clearance. It can drive at x4 at 20m/s (the rover can't really go faster)

Edited March 20, 2016 by Warzouz

[Majorjim!]

4 hours ago, Warzouz said:

I'm currently attempting a nightly 550km trip on Eve at 20m/s speed on x3 physical time warp using MechJeb Rover Autopilot.

EDIT : after more than one hour and 250km done, everything goes smoothly. I've tried to go to x4, but the rover blow every 30km. On the other hand, I'm testing with the previous prototype. The published version has a higher ground clearance. It could work at x4.

EDIT 2 : 560km done. I meet with the latest version of the rover which has higher ground clearance. It can drive at x4 at 20m/s (the rover can't really go faster)

That's awesome that it can time-warp and be stable man! Oh and I can click the un-clickable picture.

[Warzouz]

10 hours ago, Majorjim said:

That's awesome that it can time-warp and be stable man! Oh and I can click the un-clickable picture.

I did a test on Mun around a crater assembly, where I was playing/jumping around. I enabled MJ and plan a 30km loop around. It did well, except crossing those high cliffs (I had to slowdown manually). On regular terrain, I can still sustain 20m/s at x3 (it was also the prototype), but SAS control must be activated. It's not as smooth as Eve.

I also tested a Duna trip of 180km, again with the low clearance prototype. I had some issue because Duna terrain can be very hard. I remember finding a 35° slope which ended with a nearly 90° angle at the bottom. Needless to say that was hard at any speed.

Finally forward brake torque is set at 100. This maybe too high for lighter bodies than Duna.

It seems MJ does a very nice job driving around. The only issue is on low gravity worlds, it should use SAS to steer and not wheels : it's less risky and more efficient.

Finally, when you loose control on a too sharp turn and your rover starts spinning, it's always possible to recover, BUT the actions you have to do must be very quick and you may not have time to figure what to do to recover the rover. MJ does it quite nicely.

[Warzouz]

Some more test with the published version.

• Mun 100km, 20m/s, x4 : success
• Duna 120km, 24m/s, x4 : success
• I noticed that Duna don't even need the medium leash

[Warzouz]

In 1.1.2, this rover is working but power production is not enough any more. I should triple the RTG, which would make this rover too expensive...

[Warzouz]

Well, finally, the rover performs well on Mun with the original 2 RTG at 25m/s at x4 physical timewarp. Of course, MJ "rover autopilot" is recommended tokeep the rover on track. As always avoid craters by using the waypoints.

I'll do some more testing.

[Carraux]

Nice construction! Very well done!

This give me some ideas for my own design plans.

[Warzouz]

2 hours ago, Carraux said:

Nice construction! Very well done!

This give me some ideas for my own design plans.

Thx. I did some more testing on Eve (well I sent rover in my career). The required energy is much higher than on the Mun. 2 RTG are not enough for a 2WD rover.

BTW : the heatshield configuration doesn't work anymore. I always lost a wheel. The inflatable heatshield is mandatory now but works very well. It's much more bulky, though.