sevenperforce

Far From Home: Single Engine

38 posts in this topic

Posted (edited)

A recent trade embargo has caused a surge in prices for engine components. As a result, the Kerbal Space Program management has created a new rule: vehicles may use no more than a single engine, and it must be recovered intact.

Your goal is to get at least one Kerbal as far from home as possible, and return, on a single stock engine. This single engine must be your only means of propulsion. No ISRU or refueling is permitted (since any single-engine SSTO would then have an infinite score). No decoupler launching, cheats, infinite fuel, or anything gimmicky. Staging is fine; you can use drop tanks as desired. You only have to recover the Kerbal and the engine, and you can do so separately if desired. RCS can be used as long as it produces no prograde acceleration at any point (e.g., it can be used for attitude control and deorbiting but not for anything prograde).

After several entries, there will be one leaderboard organized into three levels: Atmospheric, Orbital, and Escape. In Atmospheric, your score is total distance traveled; in Orbital, your score is your apoapsis (with periapse over 70 km); in Escape, your score is your velocity at the edge of Kerbin's SOI. For all levels, you get a 150% multiplier for each additional Kerbal; for the latter two levels, you get a 2x multiplier for each world you land on.

LEADERBOARD

Level 3: Escape

Level 2: Orbital

  • @Dman0829 (83,553 km * 1.5^14 = 24,391,566 km)
  • @Aetharan (83,555 km)
  • sevenperforce (256 km * 1.5^1 = 384 km)

Level 3: Atmospheric

  • (no entries yet)
Edited by sevenperforce

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Question: Does Solid rocket boosters (of all size, including the Sepraton and LES) count as an engine or not?

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8 minutes ago, Jestersage said:

Question: Does Solid rocket boosters (of all size, including the Sepraton and LES) count as an engine or not?

Yes. If it pushes the craft in a prograde direction, it's an engine.

You can use sepratrons to help with stage separation if you want, as long as they don't produce prograde acceleration on the main vehicle.

I will edit the OP to note that RCS thrusters are fine as long as they aren't used for prograde acceleration at any time. They can be used for retrograde acceleration (e.g., deorbit burns). 

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Posted (edited)

Hold my beer.

 

Edited by icantmakemodels
Progress report #2
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55 minutes ago, icantmakemodels said:

EDIT: Am I allowed to use multiple engines as long as they're all together? e.g., a cluster of six "Vector" Engines

EDIT2: Are we allowed sepratrons, as long as they're for seperating?

No, you cannot cluster engines. You can only use one engine, and it must be stock. 

As I stated above, sepratrons and RCS thrusters are fine as long as they aren't used to thrust prograde. They can be used to thrust retrograde for your final deorbit burn if needed (for example, if you've jettisoned your engine for independent re-entry and you need to deorbit your capsule).

 

 

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What about recovering the engine and re-launching it? Or do I have to make a re-fueling rig?

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Posted (edited)

Apogee 83,553,434(could exit kerbins soi)

15 Kerbals

S3-KS 25x4 "mammoth" liquid fuel engine

Score 2,506,603,000

Video Evidence Coming

Edited by Dman0829

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5 minutes ago, icantmakemodels said:

What about recovering the engine and re-launching it? Or do I have to make a re-fueling rig?

No ISRU or fuel transfer. One launch.

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So as long as I launch the fuel, the refit rig, and everything else all at once, I'm good?

 

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12 minutes ago, icantmakemodels said:

So as long as I launch the fuel, the refit rig, and everything else all at once, I'm good?

 

On a single engine, sure.

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If you escape kerbin, how is it scored?

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26 minutes ago, zeta function said:

If you escape kerbin, how is it scored?

Highest velocity at escape, I suppose. But remember that you've got to actually return to Kerbin, so....

Here's my entry, just for fun. Obviously this could be way better.

256 kilometers!

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Posted (edited)

39 minutes ago, sevenperforce said:

Highest velocity at escape, I suppose. But remember that you've got to actually return to Kerbin, so....

 

if it is measured by highest velocity at escape, then Dman's score would drop a lot if he decided to escape instead, the only thing I can think of this moment is distance from kerbins orbit.

But that would be a large gain for a little velocity change.

Edited by zeta function
Not a very sound scoring system.

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I managed to get past duna, but then i burned up in re-entry.

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@sevenperforce Is a dual mode engine like the RAPIER ok?

1 hour ago, sevenperforce said:

Highest velocity at escape, I suppose. But remember that you've got to actually return to Kerbin, so....

For crafts that manage to escape Kerbin you could have a separate leaderboard with AP above Kerbol

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This is not a real entry, just a proof-of-concept.

Never underestimate the power of the Twin-Boar. With a couple of drop tanks, a Twin-Boar can give the single-kerbal capsule and some other payload over 6500 m/s of delta-v. After a bit too steep ascent, I had around 3250 m/s left at LKO.

silly_thing_1.jpeg

Kerbin's orbital period is 1 year. If you launch into interplanetary space with an integral number of years as the orbital period, you will encounter Kerbin after a single orbit. I chose an easy orbit, where the encounter is at the periapsis and the apoapsis is 1 year after the launch. This required a bit over 1280 m/s for the launch, and around 2 m/s for fine-tuning the encounter at the apoapsis.

I was left with almost 2000 m/s for managing the reentry and landing.

Spoiler

silly_thing_2.jpeg

That was necessary, as there is a lot of dry mass for the cross-section. On the other hand, because the Twin-Boar has a high impact tolerance, you don't have to carry enough parachutes for a safe landing. Especially if you manage to hit the ocean.

silly_thing_3.jpeg

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Posted (edited)

1 hour ago, zeta function said:

if it is measured by highest velocity at escape, then Dman's score would drop a lot if he decided to escape instead, the only thing I can think of this moment is distance from kerbins orbit.

But that would be a large gain for a little velocity change.

Escape automatically beats a high-apogee orbit, so increased velocity at escape is a pretty good metric.

6 minutes ago, Jouni said:

This is not a real entry, just a proof-of-concept.

Never underestimate the power of the Twin-Boar. With a couple of drop tanks, a Twin-Boar can give the single-kerbal capsule and some other payload over 6500 m/s of delta-v. After a bit too steep ascent, I had around 3250 m/s left at LKO.

Wow, very nice! Top of the leaderboard, you are.

What was your escape velocity?

I really should come up with a way to add a multiplier or alternate scoring mechanism for landings on other worlds.

I wonder what a Twin Boar could do for a horizontal-launch-with-staging, like I used.

Edited by sevenperforce

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So whats the definite scoring for out of kerbins soi. In theory any vessel with correct timing could make it to eeloo and return for almost no delta-v with gravity assists and returning much the same. This challenge might need to be redone or with some limitations or instead of including orbits use the total distance in the atmosphere on a single jet.

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Posted (edited)

Well, my first SSTO to actually, y'know, orbit has achieved an AP of 83,554,619m and returned in one piece!

And a suggestion for scoring wildly disparate entries:  Do three brackets.  1) No orbit?  Ground distance covered.  2) Kerbin orbit?  Highest AP.  3) Kerbol orbit?  Highest AP + PE.

Edited by Aetharan
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14 hours ago, ManEatingApe said:

@sevenperforce Is a dual mode engine like the RAPIER ok?

Absolutely. Any stock engine is fine. If you can get something off the ground with an ion engine, more power to you.

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Posted (edited)

How about for Kerbin-escape missions, score by Apoapsis above Kerbol -- the same way the K-Prize does it.

For scoring: Ditto @Aetharan

---

Still working on the infinite-range HMB craft. Although I think that the single-launch restriction is pointless since we can only have one engine anyway. How about "Infinite launches as long as you don're re-launch your single engine."

Edited by icantmakemodels

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29 minutes ago, icantmakemodels said:

Still working on the infinite-range HMB craft. Although I think that the single-launch restriction is pointless since we can only have one engine anyway. How about "Infinite launches as long as you don're re-launch your single engine."

Because you want to have the same craft come back and refuel using engineless tankers "launched" onto the runway? That wouldn't be allowed, no. That's why I said no refueling or ISRU. The point is to get as far as you can with only the fuel you can lift using a single engine.

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Posted (edited)

My evil plan:

1) Launch a tank into orbit.

2) Return to the runway.

3) Pick up another tank.

4) Repeat from step 1 as necessary

5) Launch jeb into orbit

6) Dock everything together

7) Go do a Jool-5 or something

8) Return home

 

At least make a multi-launch-refueled-still-no-isru leauge.

Edited by icantmakemodels
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1 hour ago, icantmakemodels said:

My evil plan:

1) Launch a tank into orbit.

2) Return to the runway.

3) Pick up another tank.

4) Repeat from step 1 as necessary

5) Launch jeb into orbit

6) Dock everything together

7) Go do a Jool-5 or something

8) Return home

 

At least make a multi-launch-refueled-still-no-isru leauge.

Well, that's not quite the spirit of the challenge; I said no refueling because I wanted people to use only the fuel they could get off the ground in a single launch. But don't let that stop you from making it!

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Posted (edited)

So, make a category for multi-launch-refueled-at-KSC and another for single-launch.

Problem solved.

Edited by icantmakemodels
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