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Lowest Cost to Orbit


Aiden.J
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3 hours ago, funk said:

Ehm... it's a SSTO every cost except fuel will be refunded when you land at KSC...

True, but thats not how i intended this to happen. It's total cost at launch, not total cost altogether.

3 hours ago, funk said:

cause it's basically the same what Wanderfound did.

It is, i'll update the leaderboards.

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19 minutes ago, GoSlash27 said:
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I couldn't quite catch @sevenperforce. $33,151/193,050 kg at launch = $0.172 /kg. Keeping in mind that this isn't actually an efficient lifter design by the usual standards, It's not a bad entry for this competition.

Best,
-Slashy

Not an SSTO either, but yeah, that's where I would have aimed if I'd been free to stage.

Although I think I would have used Thumpers; they have a lower wet mass/cost than any other SRB. However, they don't have quite the ISP for the final push into LKO, which is why I primarily used Kickbacks on my SSTO.

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2 minutes ago, sevenperforce said:

Not an SSTO either, but yeah, that's where I would have aimed if I'd been free to stage.

Although I think I would have used Thumpers; they have a lower wet mass/cost than any other SRB. However, they don't have quite the ISP for the final push into LKO, which is why I primarily used Kickbacks on my SSTO.

Actually, I think going SSTO gives you a bit of an advantage. SRBs are cheap and it doesn't matter how much "payload" gets orbited in the end. I'm still thinking too conventionally :D

I suspect this whole competition will be dominated by SRBs.

Best,
-Slashy

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3 minutes ago, GoSlash27 said:

Actually, I think going SSTO gives you a bit of an advantage. SRBs are cheap and it doesn't matter how much "payload" gets orbited in the end. I'm still thinking too conventionally :D

I suspect this whole competition will be dominated by SRBs.

Best,
-Slashy

Au contraire; going SSTO was a real pain. I must have flown that 20 times before I got the perfect ascent.

If I'd just done basic serially-staged Kickbacks, it would have been easy.

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19 minutes ago, sevenperforce said:

Au contraire; going SSTO was a real pain. I must have flown that 20 times before I got the perfect ascent.

If I'd just done basic serially-staged Kickbacks, it would have been easy.

Easier to fly, sure... but more expensive. I orbited some 15 tonnes of ore, which is actually more expensive per tonne than orbiting a fully loaded Kickback and it contributes nothing. Plus there's the cost of the decouplers & struts. If going for the ultimate cost/launch mass in this competition, I think the SRB SSTO is going to wind up cheapest.

Best,
-Slashy

Edited by GoSlash27
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On 1/28/2018 at 9:01 AM, Aiden.J said:

True, but thats not how i intended this to happen. It's total cost at launch, not total cost altogether.

If the entrant shows the funds recovered after returning to KSC, that should be deducted from the cost of the launch. That's the whole point of building a reusable vehicle in KSP. 

Separate leaderboards is a good way to go with that, but to keep it consistent with the game and many past challenges of this kind, you're best off reporting the cost based on the actual money spent and recovered in game.

i.e. Cost = [Cost at Launch] - [Cost of Payload] - [Amount Recovered] 

Otherwise your readers (like me), are very confused as to how a non-reusable entry did so much better than the reusable ones, and have to sift through your discussion before realizing, "oh, this guy ignored funds recovered. That doesn't match how KSP works." 

Obviously entrants should show the actual funds recovered screen, because you spend fuel getting back down, and accurately landing matters for the recovery percent, too. 

You've got separate leaderboards so you're not marginalizing the efforts of the non-recoverable people, but by ignoring the recovery amounts, you're misleading readers about the actual performance they'd get from the different crafts if they used them in their own games. 

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Oh well, I didn't notice this challenge had a deadline before I did it. Anyway, here's my entry, the Inexpensive Donkey. It's 100% solid fueled and uses overheat staging, because cubic octagonal struts are cheaper than decouplers. :sticktongue: It's also manned, since the Mk1 command pod is cheaper (and heavier!) than a low-tier probe core plus a small reaction wheel. It  weighs 37,595 kg at launch and costs 4,986 √, or just 0.132624 √ per kg.

The overheat staging actually almost ruined the flight, because there's something funny with the RT-5 Flea engine's plume that causes the strut not to heat up as it should. If you want to try this craft, I very much recommend using the move tool to pull the strut below the Flea engine down a notch or two, so that the game actually considers it to be in the plume.

Also, as a side effect of the hacky staging, KER miscalculates the delta-v, since it thinks I'm hauling all the spent stages with me to orbit. I didn't bother to do a manual calculation, but the true delta-v is surely well over 3400 m/s.

Screenshots:

Spoiler

IZ7jqyV.png

The Inexpensive Donkey in all its glory. A total of 16 parts massing 37,595 kg at a cost of just 4,986 kerbucks.

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On the launch pad. Jeb can't wait to test this.

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We have liftoff!

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First stage separation at T+1:07.

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Tilting over after first stage separation. I didn't tilt over quite enough at launch, and lacked the control authority to correct that while the first stage was attached, so I ended up flying the first part nearly vertically and had to correct for it later.

ImTiu0E.png

Apoapsis is in space, burning towards the horizon to gain orbital speed.

82CiAP2.png

Third stage ignites, second stage explodes. :) The maneuver node is roughly at apoapsis to provide a heading for Jeb to hold.

vxlNrnw.png

Burning to raise periapsis.

O5BNTkp.png

Third stage was almost enough to reach orbit. If I'd flown the gravity turn better, it might actually have been enough. Fortunately I've got one more stage left.

u2D7xQg.png

Final stage ignition at apoapsis. For some reason, the overheat staging isn't working this time. :( Fortunately, the Hammer engine eventually explodes, and despite some uncontrollable spinning, the remaining thrust in the fourth stage is enough to raise the periapsis over 100 km.

Sezz9at.png

There's a strut stuck in my engine. Why is there a strut stuck in my engine? :huh:

o19OBRJ.png

Oh well, made it to orbit anyway. Now, how do I get down again..? 

 

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On 1/22/2018 at 7:48 PM, Aiden.J said:

Hello! Today, your challenge is to achieve orbit with the most minimal cost to weight ratio.

RULES- 

NO CHEATING

No cheat menu (Alt-f12 menu)

No mods that add parts/change game mechanics (MechJeb and KER and the such are allowed)

No altering game files

Minimal part clipping (the screenshot of the rocket in the VAB/SPH must show the final design)

To find cost/weight ratio, simply divide cost by weight (in kg, not tons). (If the delta-v is below 3400 m/s, i will also add additional points where necessary, but i haven't figured out the formula :/)

PARAMETERS-

Orbit must be roughly equitorial, prograde respecting Kerbin's rotation, as well as have a periapsis of 100km+

To enter, include screenshots of the rocket/SSTO in the VAB/SPH, a screenshot of the rocket in suborbital flight in the atmosphere, as well as a screenshot of the rocket in it's final orbit.

*ALL SCREENSHOTS MUST INCLUDE KERBAL ENGINEER, OR SOMETHING THAT SHOWS WEIGHT, DELTA-V, AND OTHER PROPERTIES OF THE ROCKET*

Make sure to include a craft file, for others to reference, and I to judge. 

If you do not have access to KER or MechJeb, but wish to enter, please include a video of the launch.

Lastly, during orbit, please include a picture of the Map screen, showing the Periapsis and Apoapsis of the orbit, or have KER or MechJeb displaying the characteristics of the orbit.

MISCELLANEOUS-

MechJeb Link (compatible with 1.3.1)- https://www.curseforge.com/kerbal/ksp-mods/mechjeb

KER Link (should also be compatible with 1.3.1)- https://kerbal.curseforge.com/projects/kerbal-engineer-redu

Hard Mode- SSTO

Another Hard Mode- SRBs

Super Mode- Impress Me

I will list rankings in respective categories, but do not expect frequent updates. 

If i make any mistakes, or you'd like to suggest changes, please leave a comment.

The competition officially ends Sunday, the 28th of January, 2018, though i may update the rankings if i see a truly amazing rocket.

A payload submission is accepted, though not listed in this challenge.

REMINDERS-

Don't forget to check your staging

HAVE FUN

Leaderboards-

Payload (SSTO)- 

1. funk (1.737 per kg)

2. Wanderfound (2.330 √ per kg)

Payload (Staged Rocket)-

1.

Normal-

1.

Hard (SSTO)-

1.

Hard (SRB)-

1.

Super Hard- 

1. sevenperforce (0.164 per kg) (SSTO and SRBs)

Wait what would happen if we reused the entire rocket?

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