Kerbin 2 challenge

[SpaceOdissey]

A lot of people knows what is the Jool 5 challenge. I've know. Land on all the five moons and return to Kerbin but if you're starting KSP and you at least pro for dock and land on Mun and Minmus why not land on the two moons of Kerbin and get back to Kerbin?

 

Dificulty ranges:

Easy: Refuel allowed, Hyperedit allowed, all sizes allowed and no maximum weight allowed.

Normal: No Hyperedit, all sizes allowed, refuel allowed max weight 60 tons.

Difficult: No Hyperedit, max size 3.75 meters, no refuel and max weight is 40 tons.

LEGEND: Max size 1.25 meters, no refuel, max weight 20 tons only, no IRSU and no docking .

The Ultimate!: Maz size 0.625, no refuel, max weight 5 tons only, no IRSU and no docking No Hyperedit Obviously...

Stock mode!: ANY mod is not allowed even MechJeb or Kerbal engineer. let's say that is a Ultimate mode with pure stock KSP!

The Clock mode!: It's easy because all sizes are allowed, also Kerbal Engineer or MechJeb BUT! You need to complete this mission on 20 Days!

 

I've do it at the difficult mode. Can you complete the LEGEND mode or a very difficult mode?? Put below in comments 

Lot of thanks to TheGamerAlchemist who maked the challenge on YouTube! :

 Also thanks to Agencia Espacial Kanada - Kanadian Space Agency...! : 

And I forgot to share this thanks to Teil Teilnehmer! Who was the first to put it on Youtube !: 

 

Edited March 26, 2017 by SpaceOdissey
More modes. Shall we?

[ottothesilent]

I think I'll make an attempt at this one. Standard screenshots of craft, transit, and landings okay?

[Nicias]

I think this qualifies as legendary.

Full album: http://imgur.com/a/Xmkbm

Then in orbit with 3387 m/s dv.

On Minmus:

On the Mun:

and back home with 91 m/s spare.

Splashdown!

[SpaceOdissey]

9 hours ago, Nicias said:

I think this qualifies as legendary.

Full album: http://imgur.com/a/Xmkbm

Then in orbit with 3387 m/s dv.

On Minmus:

On the Mun:

and back home with 91 m/s spare.

Splashdown!

Really?! Did you complete the LEGEND mode?!  Amazing! 

[Superfluous J]

I made a 16ish tonner just now and got it into LKO and I *THINK* it has the dV to make the run. However I have no idea if my parachuteless, fuelless design will survive re-entry, especially because I don't even have the fuel to slow down upon return from Mun. Assuming I have the fuel to actually return from Mun.

I also don't know when I'll be able to actually complete the run.

Edited February 1, 2017 by 5thHorseman

[tseitsei89]

Here is an entry I made for another challenge a while back. It is extremely light and uses only 1.25m or smaller parts so should qualify for Legend category. I might have to try and see if Ultimate category can be done.

[CaptainTrebor]

I think I'll have a shot at this, considering I have a <0.7 tons SSTO, that with more fuel and therefore power should work.

[tseitsei89]

Hmm... the problem seems to be drag. Since there is no 0.625m fairing the craft will be extremely draggy. Plus you also have to do some "creative" solutions for re-enrty since service bays, fairings and all crew modules are 1.25m or bigger  And that creative re-entry solution will probably further increase your drag since it has to be big enough to hide the kerbal completely.... I wasn't able to (quickly) find a way to do all of this at once.

[Leafbaron]

is the ultimate difficulty even doable? The spark with 16 kN of thrust on the launch pad and if the vehicle is 5 tons only had .33gs accelerations. adding 4 to achieve the required thrust for lift off plus the other equipment needed would put your dry mass at roughly 1 ton. ln (5/1)*9.81*310 (averaging out atmospheric burn time with near vacuum isp) gives you roughly 4900 m/s of dv. 3500 to get to LKO, 853 to get to mun, 250 for orbit circulation, another 500-600 to land, then another 500-600 to orbit again, then another 100 to escape mun. then minmus. already we are at 5700 m/s of dV just to land and get back to orbit at the mun. If you time it right and use the ejection burn at the mun to encounter minmus, you'd need probably 80 ms to circularize at minmus then 160 to land. then 160 to orbit again then at least 180 to return back to kerbin. TOTAL DV is roughly 6280 m/s.  I suppose you could use the ion engine and achieve the proper thrust to land on the mun but then electric charge becomes worrisome. I don't think the ultimate challenge is doable i just don't see a way to achieve the required TWR and d/v requirements with only 5 tons. 

Edited February 1, 2017 by Leafbaron

[tseitsei89]

40 minutes ago, Leafbaron said:

is the ultimate difficulty even doable? The spark with 16 kN of thrust on the launch pad and if the vehicle is 5 tons only had .33gs accelerations. adding 4 to achieve the required thrust for lift off plus the other equipment needed would put your dry mass at roughly 1 ton. ln (5/1)*9.81*310 (averaging out atmospheric burn time with near vacuum isp) gives you roughly 4900 m/s of dv. 3500 to get to LKO, 853 to get to mun, 250 for orbit circulation, another 500-600 to land, then another 500-600 to orbit again, then another 100 to escape mun. then minmus. already we are at 5700 m/s of dV just to land and get back to orbit at the mun. If you time it right and use the ejection burn at the mun to encounter minmus, you'd need probably 80 ms to circularize at minmus then 160 to land. then 160 to orbit again then at least 180 to return back to kerbin. TOTAL DV is roughly 6280 m/s.  I suppose you could use the ion engine and achieve the proper thrust to land on the mun but then electric charge becomes worrisome. I don't think the ultimate challenge is doable i just don't see a way to achieve the required TWR and d/v requirements with only 5 tons. 

Weight limit is really not the problem. The lack of 0.625m parts is. We dont have any fairing or any good parts for re-entry + all parts are VERY draggy without the fairing. Plus all good airbreathing engines are 1.25m...

[W. Kerman]

I used this tool, and it's a bit outdated, but for that much delta V 

https://garycourt.github.io/korc/

It was spitting out designs just under 9 tons. I think this may by impossible.

 

 

(Looks at Turbopumped's videos)

....Alright, NEAR IMPOSSIBLE

[The_Rocketeer]

21 hours ago, Leafbaron said:

is the ultimate difficulty even doable? The spark with 16 kN of thrust on the launch pad and if the vehicle is 5 tons only had .33gs accelerations. adding 4 to achieve the required thrust for lift off plus the other equipment needed would put your dry mass at roughly 1 ton. ln (5/1)*9.81*310 (averaging out atmospheric burn time with near vacuum isp) gives you roughly 4900 m/s of dv. 3500 to get to LKO, 853 to get to mun, 250 for orbit circulation, another 500-600 to land, then another 500-600 to orbit again, then another 100 to escape mun. then minmus. already we are at 5700 m/s of dV just to land and get back to orbit at the mun. If you time it right and use the ejection burn at the mun to encounter minmus, you'd need probably 80 ms to circularize at minmus then 160 to land. then 160 to orbit again then at least 180 to return back to kerbin. TOTAL DV is roughly 6280 m/s.  I suppose you could use the ion engine and achieve the proper thrust to land on the mun but then electric charge becomes worrisome. I don't think the ultimate challenge is doable i just don't see a way to achieve the required TWR and d/v requirements with only 5 tons. 

Based on my experience and unfinished experiments, maybe vOv

But you're making some mistakes: the first is, don't go to Mun first. Do Minmus first, and do Mun when your mass is less so it uses less fuel.



EDIT: According to KER here are stats for my current ship:

3 Stages
4.86 t
6371 dV
1.22 TWR

Based on your numbers, that should do it.

Re-EDIT:

Ok, I just realised something that perhaps some of you didn't, or didn't realise something that some of you did.

@SpaceOdissey does the ship have to be manned? Since you have not made this an explicit criteria of the challenge, I had assumed no, but if I am wrong then everything above is irrelevant.

Edited February 2, 2017 by The_Rocketeer

[Nicias]

I did it with 6390 and finished with 91ms left over. So 6371 should be enough, if you can get to orbit with 3300 or so left.

[Leafbaron]

23 minutes ago, The_Rocketeer said:

Based on my experience and unfinished experiments, maybe vOv

But you're making some mistakes: the first is, don't go to Mun first. Do Minmus first, and do Mun when your mass is less so it uses less fuel.



EDIT: According to KER here are stats for my current ship:

3 Stages
4.86 t
6371 dV
1.22 TWR

Based on your numbers, that should do it.

Re-EDIT:

Ok, I just realised something that perhaps some of you didn't, or didn't realise something that some of you did.

@SpaceOdissey does the ship have to be manned? Since you have not made this an explicit criteria of the challenge, I had assumed no, but if I am wrong then everything above is irrelevant.

Im not sure if the order matters. gravity is gravity and it must be paid. if you were working with a lower TWR and it required the ship to be less full for the mun then i would say flip flop them. I just assumed it needed to be manned, but it does not explicitly say whether it needs to be or not. so long as your dry mass is .5 tons and your rocket as at least 310 isp average. you can achieve the required d/v to do it. but if you made one thats awesome!

I can't wait to see it. your dV margins are gonna be tighter than a drum in the texas heat. 

[The_Rocketeer]

54 minutes ago, Leafbaron said:

Im not sure if the order matters. gravity is gravity and it must be paid.

The order certainly matters. Almost all fuel will be burnt during ascent to Minmus altitude, so taking any of that fuel to the surface of Mun is a waste of dV. The fuel needed to return from Minmus will be less than the fuel needed to return from Mun under any circumstance, and reaching Mun SOI on the way down is only a matter of timing. Landing and taking off again from Mun will be considerably cheaper if not carrying any excess wet mass, and then you're back in freefall to Kerbin.

[Leafbaron]

3300-3500 to get to orbit, 960 to minmus, 80 to circularize, 170 to land, 170 to orbit again, 150 to escape minmus, 200-250 to cicularize at mun, 500-600 to land, 500-600 to take off, 200 to return to kerbin. total 6300-6500 total d/v. 

I still believe the order doesn't matter. we are in an energy debt to gravity and it must be paid. 

[The_Rocketeer]

1 hour ago, Leafbaron said:

We are in an energy debt to Kerbin's gravity and it must be paid. 

Fixed that for you. The cost to Kerbin's gravity is the same whatever the order. However, when we descend into another gravity well, we create a new debt commeasurate to both the strength of the gravity field and the mass of our vessel at the time that we do so.

Mun's gravity is stronger than Minmus', so when we travel around with a big bag of money (fuel) with which to pay our expenses (dV), it simply costs more to bring the money to pay for both to Mun than it does to bring the same money to Minmus, because the money is heavier on Mun, and the cost of bringing it is greater per coin.

Anyway, try it out. Build a rocket that can do the round trip, and try it both ways. Best way to learn.

Edited February 2, 2017 by The_Rocketeer

[Nicias]

But, you gave to lift more extra fuel off minmus so even though it is less per unit of fuel it is the same overall

[Superfluous J]

5 hours ago, Leafbaron said:

I still believe the order doesn't matter. we are in an energy debt to gravity and it must be paid.

You have the same (or similar) dV requirement for the 2 paths, but dV is not fuel. Going to Minmus first saves fuel because it uses less fuel to land and lift the "Mun fuel" on and off of Minmus than it does the "Minmus Fuel" on and off of Mun.

The good news here is you don't have to trust anybody. Hack a ship with - say - 5000 m/s of dV in it and a decent TWR into LKO, make a named quicksave, and then do the mission going to Mun first. When you have a periapsis within Kerbin's atmosphere check your dV left over. Then do the same mission, going to Minmus first, and check your dV again when you've got a periapsis within Kerbin's atmosphere.

Unless you're doing something blatanty inefficient in the "Minmus first" run, it'll win every time.

[Leafbaron]

doing it right now. 

[Leafbaron]

Here's the link to the Mun first run - http://imgur.com/a/tH1De,  6,954 m/s dV I set everything up and Mech Jeb executed for consistencies sake. 

Here's the link to the Minmus first run - http://imgur.com/a/TOwnS, 6978 m/s dV, I apoligize, i didn't get all the photos  for this run, thought i was hitting F1 but i didn't capture dV readings after every manuever. Starting craft was the same as in mun first mission. total dv invac on launch pad was 8327 m/s 

I just quicksaved when i was in orbit of kerbin. then started each run from there. when i did the minmus run i hyper edited craft to 0 inclination with minmus orbit, i assume if you were doing minmus first you would launch into matching planes with minmus. so there was no plane change to encounter minmus. 

I flew both missions with identical efficiency, and the difference is negligible. Fuel is dV, what do you think goes out the back of the rocket to make you move? the mass of the fuel is being thrown out the back of the rocket at high velocity. fuel IS your potential for change in velocity. 

Edited February 3, 2017 by Leafbaron

[Gordon Fecyk]

Low-Tech Space Plane and 4.5 t Lander to Kerbin 2

I wanted to see if I could lift a suitable craft to LKO with @Thrimm's LTS Kestrel, modified for Ferram Aerospace. This was my first complete result. All craft and crew returned to KSC undamaged and unharmed, even if it took fifty-five Kerbin days or so. Note that this version of FAR is the dev build and aero behaviour may change with the final release.

The Craft: LTS Kestrel-FC:

42 tonnes including 4.5 tonne lander. No parts higher than Tier 5 tech, I think. I'll try to shave two tonnes off somewhere to qualify for 'Difficult.'

The Lander: "Lawn Chair v2:"

Just over 4.5 tonnes, with small reaction wheel, battery, antenna, FL-T800 tank and Spark engine. Command seat only inside Mk1 service bay.

I'll link to the remaining pictures rather than create a huge picture post. I don't use Imgur and I thought albums were still broken.

• Val prepares by pocketing two flags
• Val loads up into the Service Bay
• Jeb treats this thing like a fighter on an aircraft carrier
• Lighting afterburners at 35 degrees pitch
• Lighting main engines at 18 km up
• MECO at 75 km AP
• Closing orbit with just 240 m/s dV
• Deploying our lander
• Plotting Mun assist to Minmus, saves at least 100 m/s (even if it does make the trip 30 days longer!)
• Course correction at Mun PE
• Minmus insertion
• Minmus landing
• Minmus Flag (Milestone reached!)
• Minmus transfer to the Mun
• Mun insertion
• Mun landing
• Mun Flag (Milestone reached!)
• Mun transfer to the Kestrel
• Low Kerbin Orbit insertion and deciding to let Kestrel do the rendezvous instead
• Jeb plotting lander rendezvous (eight hours faster than letting Val do it)
• Val completing rendezvous and pushing the lander into the bay (She closed one of the doors to align the craft)
• After fifty days or so Val gets a comfy seat
• Set a course for home, Jeb
• Re-entry was surprisingly sedate when there's a load closer to the front
• Oops, Jeb overshot (it was either that or risk destroying air frame trying to turn at Mach 2)
• Is this a runway or an aircraft carrier?
• From Mach 1 to zero in about ten gees (ouch!) (This also would have killed the KSP 1.1.3 wheels)
• In the end, ship, lander and crew safe at home (and didn't need to reload once!)

I have video of all of this, but it'll take some time to cut. The craft is in the FAR Craft Repository thread at the Spacecraft Exchange.

 

Edited February 4, 2017 by Gordon Fecyk
Added FAR dev build disclaimer

[Gordon Fecyk]

9 hours ago, Leafbaron said:

Fuel is dV, what do you think goes out the back of the rocket to make you move? the mass of the fuel is being thrown out the back of the rocket at high velocity. fuel IS your potential for change in velocity.

I have a problem with this assertion after flying my attempt last night.

It appeared to take three times more time to do my Minmus insertion at 161 m/s (1m 33s) than it did to do my Mun insertion at 207 m/s (30s). Granted, this is the stock estimated burn time, but this is usually close enough and these are based on full thrust. By Mun insertion, I had just-slightly-less than half of my fuel remaining.

[The_Rocketeer]

17 hours ago, Leafbaron said:

Fuel is dV, what do you think goes out the back of the rocket to make you move? the mass of the fuel is being thrown out the back of the rocket at high velocity. fuel IS your potential for change in velocity. 

As I pointed out previously, dV requirement/cost/demand depends also on local gravity. It will take less fuel-mass-thrown-out-the-back-of-the-rocket to move the same vessel mass on Minmus than it will on Mun. Your experiment results are interesting, but I would like to see your methodology before accepting it as a groundbreaking development in our understanding. Perhaps there is something about the 'closed loop' flightpath that @5thHorseman and I are overlooking, but I doubt it.

 

@SpaceOdissey still waiting for clarification on the manned/unmanned question.

Edited February 3, 2017 by The_Rocketeer
Disambiguation

[The_Rocketeer]

26 minutes ago, Gordon Fecyk said:

I have a problem with this assertion after flying my attempt last night.

It appeared to take three times more time to do my Minmus insertion at 161 m/s (1m 33s) than it did to do my Mun insertion at 207 m/s (30s). Granted, this is the stock estimated burn time, but this is usually close enough and these are based on full thrust. By Mun insertion, I had just-slightly-less than half of my fuel remaining.

@Gordon Fecyk could you clarify what the problem with the assertion is?

There are a lot of reasons why a less-than-efficient Minmus insertion will be much more costly than a less-than-efficient Mun insertion, but the most likely candidate for your current experience is that you are not launching your mission to account for Minmus' orbital inclination. This can be eliminated by timing your launch or angling your launch trajectory so that you don't need to make an additional plane change manoeuvre after reaching orbit.

If you haven't done this, your Minmus insertion burn will include a large allowance for plane-change, which is a very inefficient way to reach Minmus. By comparison, Mun's orbital inclination is 0, so you never need to change planes and therefore never risk using extra fuel as long as you launched into a vaguely equatorial orbit.