An Extended Vacation

[MagiMaster]

@Epthelyn, Is the Near Future VASIMR roughly similar in weight and Isp (at that thrust) to 120 ion thrusters? I haven't had a chance to look into it yet.

@Hakari, Do you have more pictures? I can't really tell what all's going on from just those three. Is this also using the Near Future Pack? And I don't really know what you mean about the crew transfer.

On a somewhat unrelated note, it looks like I'm going to have to start my attempt over. My lander is on Moho, but it doesn't have enough fuel to get off. I had more than twice the dV listed in the various dV maps, but even with mechanical assistance, it took too much to land. I might could have tried again, but I quicksaved just before take off.

Edited January 20, 2014 by MagiMaster
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[Hakari]

@Epthelyn, Is the Near Future VASMIR roughly similar in weight and Isp (at that thrust) to 120 ion thrusters? I haven't had a chance to look into it yet.

@Hakari, Do you have more pictures? I can't really tell what all's going on from just those three. Is this also using the Near Future Pack? And I don't really know what you mean about the crew transfer.

On a somewhat unrelated note, it looks like I'm going to have to start my attempt over. My lander is on Moho, but it doesn't have enough fuel to get off. I had more than twice the dV listed in the various dV maps, but even with mechanical assistance, it took too much to land. I might could have tried again, but I quicksaved just before take off.

with just NTR and chemical rockets.

mission profile is mostly the same, Moho>Eeloo, but then Jool and Duna flyby before returnning.

[MagiMaster]

I'll go ahead and add you to the leaderboard, but what all mods are you using? I can't tell if some of those are new parts or just new textures. Do you happen to have a picture of the two transferred crew returning?

[Hakari]

I'll go ahead and add you to the leaderboard, but what all mods are you using? I can't tell if some of those are new parts or just new textures. Do you happen to have a picture of the two transferred crew returning?

Mostly KW rocketry for tanks, space shuttle engine for the 3.75m main tank, and aerospike main launch engine. The nuke engine has a different red flame but that's just cosmetic.

As for the 2 kerbals switched out, they're still orbiting Eeloo I didn't return them yet, need another launch to do that.

I didn't think total mass accounted for the vehicles you dock with? And the crew transfer just to get them into the EVA seats?

Edited January 20, 2014 by Hakari

[Jasonden]

Okay, been working on this ever since I saw it on Friday I guess it was. I wanted a chance to try out the amazing Trajectory Optimizer, and this is it! I took gravity assists from Jool on the way out to Eeloo and then on the way back down to the inner solar system, too. Which is why the whole thing took me 15 years. OTOH I ended up having significantly overdesigned, with maybe 5000m/s dV left over once I got back to Kerbin.

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Mods: MechJeb2, PreciseNode, CrewManifest, TAC Fuel Balancer, KAS, StretchyTanks . . . probly others

[Hakari]

using all aerospike is not optimal because it has lower TWR, both weight and thrust will cause you to burn more fuel. You also had non-optimal staging with too many stages, and a huge upper stage.

Without FAR you should go for 2 or 3 traditional stages with roughly same dv, or a bunch of asparagus stages each with roughly same dv, and should be able to achieve orbit with 4500m/s, at a 7:1 launch mass ratio.

[Jasonden]

using all aerospike is not optimal

I just grabbed a rocket off my shelf -- was designing for the mission mostly, not the launch vehicle.

Interesting that everyone else seems to have gone for Moho first, not Eeloo like I did.

Edit: Just did a test run for the rocket; if I load it up I get a launch mass ratio of 708:108 with 4505dV. That seems competitive with what you're talking about. Seems the aerospikes do just fine.

Edited January 20, 2014 by Jasonden

[MagiMaster]

@Hakari, Ok. Thanks. The mass would be the total mass launched for the entire mission, including any refueling or crew transfers.

@Jasonden, Nice. With two orange tanks on just one nuclear engine some of those burns must have taken a ridiculously long time. It looks like you got the reused lander, the two flybys and the no orbital construction achievements.

[Hakari]

In that case there were two fuel probes at 430t each, 180t main vehicle, adding up to 1040t

[MagiMaster]

Thanks. I'll update the leaderboard. Does that include a craft to return the swapped crew members around Eeloo?

I've been playing around with the Near Future Pack a bit and while it's not easy to, it does look like you can build significantly higher dV craft with it.

Edited January 20, 2014 by MagiMaster

[Jasonden]

With two orange tanks on just one nuclear engine some of those burns must have taken a ridiculously long time.

Yes. Yes they did I was at 1 m/s^2 for quite a while. Its okay -- for a 2000 m/s burn I just set it up, put MechJeb on it, and get a cup of coffee.

[Kasuha]

After number of attempts I finally found a way how to do a reasonable gravity slingshot to Moho. 700 m/s braking burn looked almost unreal to me, with total of about 2700 m/s from high Kerbin orbit to Moho parking.

The rest of the journey should not be a big problem now.

[MagiMaster]

Good luck with the rest of the trip. I'm still stuck in the VAB redesigning my craft.

[Kasuha]

The ship has already climbed the Eve/Kerbin/Kerbin slingshot ladder from Moho and is about to run into Jool (in 7 years or so) but it takes time and I have only so much of it so I'll continue tomorrow. Hopefully it will still have enough fuel left for landing and return to Kerbin after it gets to Eeloo.

[Kasuha]

I finished the challenge, total MET was almost 7610 days so it was totally a very extended vacation for Jeb. Did it with my "standard" ship, not very optimized and it would normally not be able to do the task so it used series of gravity slingshots to get all the way to Eeloo. Only the hop from Eeloo back to Kerbin was straight.

I'll upload images during tomorrow.

[Kasuha]

Here we go. It was a nice lesson on gravity slingshots to me.

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[Alchemist]

Now I want to try...

The plan is:

1) Land on Eeloo

2) Land on Dres (alternate variant - Duna or Ike)

3) Meet another ship in Dres (or whatever) orbit, refuel and swap the crew.

4) Moho transfer with Eve gravity assist?

5) Land on Moho

6) Get back

Main ship definitely is my single launch to Moho design (probably a bit rearranged), during landings it leaves external tank in orbit.

[Jasonden]

Here we go. It was a nice lesson on gravity slingshots to me.

Nice -- with 6 nukes you certainly had better TWR than I did. Makes long burns much less painful

[chlue]

Hello, my entry with a 'Near Future Pack'-based ship.

total mass launched:

282.6t main ship

213.2t fuel ferry (over sized by a big margin)

91.7t crew transfer, because I forgot to put kerbals in the lander and realized this in a 900km orbit (Hopefully this ship does not count )

--> either 495.8 or 587.5t (Yes I know these numbers are quiet bad, but I was to lazy to optimize the launchers)

Mission should qualify for:

- Complete the mission.

- Land on Eeloo and Moho with the same lander.

- During the mission, fly by at least two different planets (Eve, Duna and Jool visited)

- Do the entire mission with no orbital construction. You can dock for refueling or crew transfer if you separate before making significant maneuvers.

- Land at least 5 kerbals on both planets.

total mission time: 7years, 213 days

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This was harder than I thought. The nearly 4.5k dv Moho circularisation burn caught me by surprise

Regarding the 'Near Future Pack'

I think it can be called quiet balanced, but the engines are surely superior to stock parts for high delta-v ships. Basically the ship feels a bit more like typical science fiction ships. Due to the high ISP the amount of propellant needed is low which makes droptanks quiet pointless. On the other hand the dry-weight is much higher (big batteries, heavy engines and nuclear reactors) so the TWR is quiet even (my had 0.22 to 0.28 over 12600 delta-v). This naturally leads to a fully reusable ship which only needs some refueling in between missions.

[MagiMaster]

Here we go. It was a nice lesson on gravity slingshots to me.

Man, how are yall getting so much dV with so many engines? I can't seem to get my designs to work out so well. Scoring wise, I may have to retweak the rules a bit since I'm pretty sure you started on this before I made the last few changes. But let's see, you reused the same lander, flew by Even and Jool, and did the mission without orbital construction. I need your total launch mass to put you on the scoreboard though.

[Mobjack]

This was harder than I thought. The nearly 4.5k dv Moho circularisation burn caught me by surprise

That happened the first time I tried to orbit Moho.

The secret is that you need to reach Moho's orbit at its periapsis. You will be traveling faster, but so will Moho and the speed will only be about a 2000 m/s difference.

When escaping from Moho, you should try to do it around its periapsis too.

Doing that will save you thousands of dV literally.

[Kasuha]

Man, how are yall getting so much dV with so many engines?

It's not that much dv in my case. I actually don't know how much it is, but usually that ship works for mission to just one planet (Moho or Eeloo). Doing anything I could to save dv for return was part of the challenge for me.

I need your total launch mass to put you on the scoreboard though.

Initial launch was 1319.98 t on launchpad

Ship with crew was 332.75 t on launchpad

Fully fueled and crewed ship in orbit before ejection burn was 163.04 t

[MagiMaster]

Hello, my entry with a 'Near Future Pack'-based ship.

total mass launched:

282.6t main ship

213.2t fuel ferry (over sized by a big margin)

91.7t crew transfer, because I forgot to put kerbals in the lander and realized this in a 900km orbit (Hopefully this ship does not count )

--> either 495.8 or 587.5t (Yes I know these numbers are quiet bad, but I was to lazy to optimize the launchers)

Mission should qualify for:

- Complete the mission.

- Land on Eeloo and Moho with the same lander.

- During the mission, fly by at least two different planets (Eve, Duna and Jool visited)

- Do the entire mission with no orbital construction. You can dock for refueling or crew transfer if you separate before making significant maneuvers.

- Land at least 5 kerbals on both planets.

total mission time: 7years, 213 days

This was harder than I thought. The nearly 4.5k dv Moho circularisation burn caught me by surprise

Regarding the 'Near Future Pack'

I think it can be called quiet balanced, but the engines are surely superior to stock parts for high delta-v ships. Basically the ship feels a bit more like typical science fiction ships. Due to the high ISP the amount of propellant needed is low which makes droptanks quiet pointless. On the other hand the dry-weight is much higher (big batteries, heavy engines and nuclear reactors) so the TWR is quiet even (my had 0.22 to 0.28 over 12600 delta-v). This naturally leads to a fully reusable ship which only needs some refueling in between missions.

I definitely like the Near Future Pack and I think it is fairly well balanced for general use, but for this mission in particular the really high Isp engines are just too big of an advantage.

Scoring wise, it looks like you got everything you say you did.

[chlue]

I definitely like the Near Future Pack and I think it is fairly well balanced for general use, but for this mission in particular the really high Isp engines are just too big of an advantage.

Yes I didn't mend to say that they are not better for this kind of mission (they clearly are), but there was some questions in this thread regarding the balancing of them and I wanted to share my findings. It is definite correct to put them on a different scoring board compared to stock parts.

[Alchemist]

*aproaching Eeloo at 2 km/s* I guess I overdid the fast intercept... Wait, that's Moho grade ship, it's designed for twice faster encounters!

Also, Kerbin-Eelo-Dres route takes 2 years. Even with the terribly inefficient faster transfers.

Current status:

Radon-1:

- Mission: main mission

- Status: Eeloo-Dres transfer

- Fuel: 23%

Radon-2:

- Mission: refueling and crew transfer

- Status: orbiting Dres

- Fuel: 60%

Full route: Kerbin - Eeloo - Dres (refuel/crew transfer) - Eve slingshot - Moho - Kerbin

Fuel estimate: adequate.

Worst case scenario - sending another craft with extra fuel to Moho