SSTO to laythe and beyond

[Thomas H.]

I messed up the mobility enhancer, so had to hack gravity to get back on bord. And i was 800 m /s short for an low Laythe orbit.

apart from that it was 3 hours well spend.

[Val]

herbal space program said:

Nicely done. I suspected that with the new Mk1 fuselages making your plane out of only those would be the best move, and it looks like you've proven that to be correct. It looks also like having the 2 nukes instead of 1 offsets the extra weight by giving you enough vacuum TWR to burn the RAPIERs closed only a wee bit getting to LKO. I expect the 2-nuke design will also have a much better chance of getting you off Laythe without oxidizer than only 1 nuke would. I'm tempted to just scrap what I have and copy your design, but that wouldn't seem right.

Thank you

Here's my first time reaching Orbit with a 3:3 Rapier/Nerv setup.

5.1 km/s dV, but only 0.39 TWR, if MJ is right. KER says 0.5, but 0 dV. Not sure which is right. Hoping to improve it.

It's also reaching a size now where, I need to use struts to keep it from wobbling. Didn't use struts on any of the previous designs.

The look is inspired by the XB-70 Valkyrie.

 

Edited January 18, 2016 by Val
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[Red Iron Crown]

I messed up the mobility enhancer, so had to hack gravity to get back on bord. And i was 800 m /s short for an low Laythe orbit.

apart from that it was 3 hours well spend.

https://youtu.be/B0tEgSY7ToY

Impressive!

I've been trying to get my capture just right, best so far has a speed of 4.2km/s when hitting Laythe's atmosphere and I can choose between burning up or only scrubbing off a couple of hundred m/s. Yours seems to occur at a much more reasonable speed.

For those asking on the previous page about the spikes on the Rapiers on my design, they are shock cone intakes clipped into the engine for drag reduction. Overall I probably should have used small nose cones for lower dry mass.

[Val]

I made it to Laythe, using the 5.2 km/s dV, M-5 Space Hustler. Had a bit over 2.6 km/s left, when I landed at Laythe.

Will be interesting to see if I can get off Laythe without Oxidizer, and how much dV is left, if I can.

Craft file

Edited January 18, 2016 by Val
Forum upgrade formatting fubar

[Red Iron Crown]

Another quick update: Turns out getting back to orbit with my plane using LF only was fairly trivial, the Rapiers seem to be able to keep thrusting at higher altitudes than on Kerbin and the plane is much lighter so I was able to get up over 1600m/s on air-breathers alone. I managed to do a dead stick landing on Laythe and get back to orbit with just over 2km/s of dV remaining, should be enough for the return (I think a direct ejection from Laythe is only a bit over 1km/s).

On the surface:

Rapiers earning their keep on the way up:

Safely in LLO:

I'll do a more thorough report when/if I get back to Kerbin safely.

[PLAD]

Impressive SSTO's. I'm the one who came up with the way to get to Jool from LKO for about 1020 m/s, and it is interesting to see whether it is better to add 1km/s to your ship's dV or to take a convoluted route to Jool. The K-E-K-K-J route should be easier than it sounds here though. There might be a problem with the two time systems available in KSP- I used the 24/365 system for those flights and I think almost everyone uses the 6/426 system now. In 6/426 time you would leave LKO on Year 2 day 155 (with a normal V of -443m/s and a prograde v of 1039m/s from a 75x75km orbit) and flyby Eve on year 2 day 353.8. Then 2 Kerbin flybys on Y3 D330.2 and Y5 D330.4 and arriving at Jool around Y8 D217. You can leave Kerbin over a 48-hour window but you have to flyby Eve within about +/-6 hours of Y2 D353.8 for the final Kerbin flyby to work. I find it impossible to pull it all off without a node editor.

I once took an SSTO to Eeloo's surface and back but like everybody I've discovered that all my old jet ships don't work in 1.0x. Now I want to try this. Thanks Val for that album showing your craft development, that's gonna help.

[Val]

... Thanks Val for that album showing your craft development, that's gonna help.

You're very welcome. I'm glad it was of use to you.

I only made it, because, like most people, I like to boast about my accomplishments It's very rewarding when someone actually finds it interesting. So thank you very much for that

Anyway, I'm about to attempt my return journey.

...Turns out getting back to orbit with my plane using LF only was fairly trivial...

I guess I don't have to worry about taking off from Laythe then. It's just a question of whether I have enough dV left and can survive arrival at Kerbin.

Will report back in a few hours, I hope.

[Nefrums]

What is the TWR of that ship in LKO?

I've been trying the Rapier/Ion setup, and can get to LKO with ~6k dv left, but only a TWR of ~0.15

[Val]

What is the TWR of that ship in LKO?

I've been trying the Rapier/Ion setup, and can get to LKO with ~6k dv left, but only a TWR of ~0.15

Mine have TWR between 0.29 and 0.41. (I've added TWR data to my album now)

Mission Update: I didn't make it back to Kerbin.

I had ~1450 m/s dV in Laythe orbit, which wasn't, too bad. But a bit of butterfingers and bad decisions regarding gravity assists, meant I got stuck missing around 10 m/s dV to hit Kerbin atmosphere for capture. My last good save was Laythe orbit and it was too late to try again.

But with everything I learned from this trip, I think, I'll start a new attempt, with a smaller ship and less dV. Will probably try with the Lightning Strike Mk.2.

[Yukon0009]

Is there any trick behind how you guys manage to SSTO with so much dV left over?

Or is it just sheer amount of fuel?

[Val]

Is there any trick behind how you guys manage to SSTO with so much dV left over?

Or is it just sheer amount of fuel?

Light weight, low drag builds. No RCS, cargo or other parts that aren't absolutely necessary for the mission.

If you interested here's:

• An example SSTO craft with instructions. At least 3750 m/d dV in LKO if you replace the cargo bay with a long Mk2 LF tank.
  
• A long, boring and un-commentated video of launch and landing of a similar, but simpler to build craft.
  
  • But it shows what speeds, altitudes and climb angles are used to get to orbit.
    

[Red Iron Crown]

What is the TWR of that ship in LKO?

I've been trying the Rapier/Ion setup, and can get to LKO with ~6k dv left, but only a TWR of ~0.15

My Rapier/LV-N plane has a Kerbin-surface relative TWR of 0.23 once in orbit, about as low as I like to go even using periapsis kicking for the ejection. A TWR of 0.15 can be made to work but is tedious, many kicks will be required to eject efficiently.

Is there any trick behind how you guys manage to SSTO with so much dV left over?

Or is it just sheer amount of fuel?

For me the tricks are:

- Reduce drag, one stack per engine.

- Reduce dry mass, the only wasted mass on my design is a cockpit that is heavier than strictly necessary, plus a solar panel and radiator that I could have done without (these were more about reducing mission failure mode).

- Use wet wings for lift.

- Low initial TWR, the Rapiers are dead mass for most of the mission so I used as few as possible. Same with the LV-N, a high TWR is not necessary in orbit so one was enough.

- Use efficient tanks, the Mk1 LF fuselage has the best mass ratio of all LF tanks.

- Ascent profile, run those Rapiers for all they're worth in airbreathing mode to reduce the fuel needed to achieve orbit.

[selfish_meme]

My Rapier/LV-N plane has a Kerbin-surface relative TWR of 0.23 once in orbit, about as low as I like to go even using periapsis kicking for the ejection. A TWR of 0.15 can be made to work but is tedious, many kicks will be required to eject efficiently.

For me the tricks are:

- Reduce drag, one stack per engine.

- Reduce dry mass, the only wasted mass on my design is a cockpit that is heavier than strictly necessary, plus a solar panel and radiator that I could have done without (these were more about reducing mission failure mode).

- Use wet wings for lift.

- Low initial TWR, the Rapiers are dead mass for most of the mission so I used as few as possible. Same with the LV-N, a high TWR is not necessary in orbit so one was enough.

- Use efficient tanks, the Mk1 LF fuselage has the best mass ratio of all LF tanks.

- Ascent profile, run those Rapiers for all they're worth in airbreathing mode to reduce the fuel needed to achieve orbit.

You could use a mk2 cargo bay, mk2 probe core and command seat, lighter than a cockpit, you can also cram more fuel in. Like my Laythe lander for my Jool tour.

[Val]

For me the tricks are:

- Reduce drag, one stack per engine.

Yeah, I should have explained what I meant with low drag builds.

And to add to that:

• Avoid radial attachment, except for the 2 necessary ones, wings and additional stacks.
  
  • That means Struts and Fuel lines, too.
    

  [*]No unused stack attachment points.

  • I do make an exception for Nervas, because the auto-fairing can cause problems.
    

- Reduce dry mass, the only wasted mass on my design is a cockpit that is heavier than strictly necessary, plus a solar panel and radiator that I could have done without (these were more about reducing mission failure mode).

Oh. I'd completely forgotten about the Mk1 Pod. I originally discarded it because, I 'needed' my crafts to look a certain way.

- Use wet wings for lift.

I don't think wet wings reduce drag directly, but maybe indirectly, because of reduced part count. Is that what you meant?

- Use efficient tanks, the Mk1 LF fuselage has the best mass ratio of all LF tanks.

The difference between Mk2 fuel tanks, and Mk1s + wingparts for similar lift, is very small. 1% in favor of Mk1+wings, according to my calculations, which may be wrong.

But, if the above assumption about less parts = less drag, then maybe there's no difference at all or maybe it favors Mk2. I guess it depends on how much part count affects drag, and is really only applicable in edge cases with extreme fine tuning of wing area, which is only possible on larger builds, I guess.

Anyway, you gave me an idea for a new 1:1 design. Thank you

[Sharpy]

I wonder about a different thing Is it still "single stage" if you drop off a stage in orbit but come back later to pick it up on the way back?

[Red Iron Crown]

You could use a mk2 cargo bay, mk2 probe core and command seat, lighter than a cockpit, you can also cram more fuel in. Like my Laythe lander for my Jool tour.

I don't like using command seats for long term missions, bad enough that the poor kerbal has to live in a cramped cockpit for several years. That said, I did try such an arrangement with some utility parts in the bay as well and it is more mass efficient. I used the inline Mk1 as it's more aesthetically pleasing to me and I could still get enough delta-V.

Yeah, I should have explained what I meant with low drag builds.

And to add to that:

• Avoid radial attachment, except for the 2 necessary ones, wings and additional stacks.
  
  • That means Struts and Fuel lines, too.
    

  [*]No unused stack attachment points.

  • I do make an exception for Nervas, because the auto-fairing can cause problems.
    

I used a similar strategy, though the vessel I'm using has two struts, two fuel lines, a solar panel and a radiator attached radially. Only the struts were strictly necessary, though.

I don't think wet wings reduce drag directly, but maybe indirectly, because of reduced part count. Is that what you meant?

Sort of. Two delta wings and two strakes let me eliminate two LF fuselages, fueslages that would add to drag especially when off prograde. Since I needed wing area anyway it seemed like a good play to use those parts to eliminate others.

The difference between Mk2 fuel tanks, and Mk1s + wingparts for similar lift, is very small. 1% in favor of Mk1+wings, according to my calculations, which may be wrong.

But, if the above assumption about less parts = less drag, then maybe there's no difference at all or maybe it favors Mk2. I guess it depends on how much part count affects drag, and is really only applicable in edge cases with extreme fine tuning of wing area, which is only possible on larger builds, I guess.

In this particular case, I didn't need the additional lift provided by the Mk2 tanks so there wasn't additional wing carried by the Mk1 version, thus the Mk1 was more mass efficient. If I was marginal on lift then it could very well be that Mk2 parts would have been better.

[Val]

I wonder about a different thing Is it still "single stage" if you drop off a stage in orbit but come back later to pick it up on the way back?

If you have enough stages, that you can drop one and still have something left, then by definition, it isn't single stage Even if you pick the other stage up later.

[Nefrums]

I managed to get my ion powered space plane to laythe yesterday, only to find out that solar panels does not work very well there. Back to the drawing board..

[Red Iron Crown]

Single stage to Laythe and back complete!

Full imgur album. (59 pics)

Highlights:

• 46 parts and 39.4 tons. Craft file (all stock).
  
• Low TWR takeoff and ascent.
  
• Three periapsis kicks before Jool transfer ejection.
  
• Two gravity assists (Tylo, Laythe) and aerobraking for Laythe capture.
  
• Dead stick landing on Laythe and high TWR ascent.
  
• Single burn ejection for Kerbin with aerocapture.
  
• Landed safely at KSC.

Mods used:

• Kerbal Engineer Redux
  
• Transfer Window Planner
  
• PreciseNode
  
• Enhanced Navball
  
• Some visual mods.

Other mods installed but not used for this mission.

[Nefrums]

Well done! And nice looking ship!

What is the mod you have that makes the planets look good? I should get some of the mods you are using. I only use KER.

Now how will I beat that?? Land on other moons as well? Hmm.. 3 of Jools moons might be doable in a single SSTO

[Val]

Single stage to Laythe and back complete!

Gratz! Awesome job. And great pictures and captions.

I've not tried again, yet. Been working on my ultralight 1:1 designs. And now I'm going away on vacation for a week, so won't be doing anything KSP until I'm back home.

[Red Iron Crown]

What is the mod you have that makes the planets look good? I should get some of the mods you are using. I only use KER.

The atmospheric effects are from the EVE-WIP mod, it only has configs for Kerbin at the moment and still has some minor glitches but is very pretty. The others mentioned are mostly for convenience, Transfer Window Planner is basically alexmoon's web tool implemented in game, and PreciseNode lets you edit a maneuver node when you can't see it, which was very useful for setting up that double gravity assist capture at Jool.

Now how will I beat that?? Land on other moons as well? Hmm.. 3 of Jools moons might be doable in a single SSTO

To Tylo and back in a single stage would be most impressive.

[Nefrums]

Thanks, will have to check out those mods. the PreciseNode one seams handy.

I was very impressed with that double gravity assist. Was that very hard do set up?

And Tylo... No!

[Red Iron Crown]

I was very impressed with that double gravity assist. Was that very hard do set up?

Somewhat. I set the correction node for a few days after leaving Kerbin's SoI so I could fiddle without time pressure, and it took quite a bit of fiddling as I used the Tylo one to fix inclination, too. I was fortunate with the relative locations of the moons that such a favorable encounter was possible. The other trick was to thrust limit the LV-N as low as it could go, this allowed the burn to be completed very precisely (and in interplanetary space it hardly matters if the burn takes many minutes).

[Nefrums]

Will have to try to do that!

The spreadsheet in you sign will come in very handy. As i am struggling to get TWR above 0.08 in my ship. I experimenting with a 2/8 Raipier/Ion setup.