0.24's Cost-Effective Lifters Challenge

[Camaron]

So, now that economy is working, Cost efficiency can be a big thing.

But, I wonder, how much weight can one thrust into orbit with the cheapest Rocket?

The challenge is basic.

Who can get the most bang for their buck?

Rules:

1) All Stock parts, and all stock physics, with the exception of FAR, in the Recovery category only.

2) Autopilot will be allowed. It's not a piloting challenge, after all.

3) Your Payload may contain mod parts, but may not in any assist the launch.

4) FAR allowed, but ONLY in the divisions which count Cost Recovery.

5) You MAY use sandbox, but you must still prove what your ship cost.

6) Prove, through photos and video, that you actually did what you say you did.

7) The Payload should be detachable and left in orbit.

8) Engines, SRB's, RCS thrusters, and any fuel which are attached to the Payload may not be used to help the craft achieve orbit.

9) The final decoupler which separates the Payload from the Lifter, will not count against your Lifter's cost. If the decoupler sticks to the Payload, it will count for part of the weight. If it stays attached to the lifter, it will not count as part of the Payload weight. Separators or docks may also be used for this task as well, and will be treated and counted the same way as decouplers.

10) The Payload is not considered part of your costs. In some cases, it may be tricky to get your parts costs out from under the payload in VAB, but you're smart people. You'll figure it out.

The lifters which get the most weight into orbit per √, will be highest.

Your Score will simply be the Cost of your Lifter, divided by the Payload's weight in Tons. Lowest score wins.

Ultra-Lightweight Lifters Category, Payloads Up To 12 Tons, without Recovery

1) 882.892: gm537's Jet Lifter

1) 1,087.694: Mesklin's "Tavrida"

2) 1,588.298: Slugy's Lifter

3) 1,751.5203: Firerunner's "Can o' Boom"

4) 2,801.5564: Tweety's "1285kg Probe Lifter v2.1"

Lightweight Lifters Category, Payloads Up To 40 Tons, without Recovery

1) 1,144.173: Mesklin's "Tavrida X2"

2) 1522.775: gm537's Lifter

3)

Middleweight Lifters Category, Payloads Up To 120 Tons, without Recovery

1) 3,171.379: MadChris48's Lifter

2)

3)

Heavyweight Lifters Category, Payloads Over 120 Tons, without Recovery

1) 1593.617: gm537's Lifter

2)

3)

========================================================================

Ultra-Lightweight Lifters Category, Payloads Up To 12 Tons, with Recovery + FAR

1) 296.57: Tsynique's Shuttle

2)

3)

Lightweight Lifters Category, Payloads Up To 40 Tons, with Recovery + FAR

1) 22.9: gchristopher's Plane

2)

3)

Middleweight Lifters Category, Payloads Up To 120 Tons, with Recovery + FAR

1)

2)

3)

Heavyweight Lifters Category, Payloads Over 120 Tons, with Recovery + FAR

1)

2)

3)

Edited August 9, 2014 by Camaron

[UmbralRaptor]

Bleah, this is not off to a good start.

I like the idea, though not necessarily the categories. (If primarily because none of the lifters I use conveniently fall just under one of them). In general, I would also be interested in other sizes in terms of √/kg, and what ones require the least science.

[Camaron]

I'll make it more Generic, then. Good points.

[NikkyD]

Im am currently playing around with the same idea but...

Payload of 25 ton is a monster, thats a payload that can reach the outter edges of the system.

How about different categories ?!

- satellite 0.5t

- manned-orbit 1.5t

- munar-trip 4t

The weight is about what an avg module of that size should have.

if you like bulky monstar-rockets, add categories 10+t but keep the payload weight fixed.

(if its not in your interest, i can start my own challenge, just let me know)

[Camaron]

I like your idea. I can split this into "Heavy" and "Light". The original intention of this is to see who can get heavy loads into space without breaking the bank. anything less than ten is just too easy, in my opinion. I've built a single-launch ship that weighed 2,900 tons in orbit, so I really wouldn't call 25 "a monster". Will be updating the OP in the next few.

Keep in mind, the way the scoring works, you could very well top the charts with a half - ton payload, if it's done cheaply enough.

Edited July 21, 2014 by Camaron

[NikkyD]

right now my best attempt to get my 3.9t into 80k orbit costs roughly 7k

critical questions (or required rules) would be: the payload needs a decoupler thats for sure, does the dc cost toward the lifter or is it included in the payload ?!

What about launch-cranes, do they count ?

[NikkyD]

this is not gonna be fun.

Just checked. With a 'new' 82t kerbo and its ultra engine u get pretty much exactly 10t into orbit. You can try to build a setup with mainsails and the old tanks but you wont get very far.

[Camaron]

Like I said earlier, if you want to use a very light payload, you're free to do that. The score is a ratio of weight to cost, so pushing the upper limit of a weight category wouldn't help you, and doing the opposite won't be a disadvantage.

Added a rule for final decouplers.

Not sure what you mean by launch cranes. are you talking about clamps that put your ship up one or two hundred meters? I'll allow it, so long as the parts are stock, and you don't go completely overboard.

[PPR]

May I suggest some kind of standard payload? That way it will be easy to replicate and compare.

[Sandworm]

All stock parts, stock physics and mechjeb is allowed? That's rather limiting. I imagine all the entries for a given lift will be very similar. The real issue would be the assent profile more than the rocket design. You would have to make the lift extremely heavy to get much differentiation in entries but that leads to silly part-counts and pancake-shaped craft.

Stock+KW+FAR would make for a much more diverse set of entries.

[NikkyD]

@sandworm

thats what i meant. Above a certain weight the solutions will be pretty similar and other factors come into play.

The difficulty is to build something really small, because you lack parts resp. a decoupler more or less can break the bank.

And if the payload is in some ugly/tricky region it might be hard to find the right design which makes a good challenge

[Tweety]

This could be fun actually. Purely to see what I can come up with if nothing else. Reserving this for an entry I don't think I will win if people actually enter though.

[bhauth]

Solid fuel rockets are cheaper than liquid fuel tanks. Huh.

Edited July 23, 2014 by bhauth

[Tweety]

Ok so I had a quick go (only about 30 minutes) and managed to get a 1310kg satellite in a stable orbit for less than 11k from what I can remember. It can be optimised so as to save funds. I will post screenshots and craft file tomorrow night.

[bhauth]

I made a quick entry.

bhauth.com/files/cheap_skater.zip

511.015 tons

424.275 w/o payload

86.74 tons payload

17% mass fraction

√144882.5

√1670.31 / ton

Mechjeb will take it to a 75km orbit.

[Camaron]

Show us some pics, I'll be glad to put you up as the first contender!

[bhauth]

btw, I'm sure it's possible to do things cheaper by using more large solid boosters, because they're much cheaper than liquid fuel tanks. I just felt like using both solid and liquid engines.

[Laie]

The one problem I have with this is that I don't make orbit and circularize, and then detach the payload. If the lifter gets the payload to within ~500-1000m/s of a proper orbit, it has done it's duty. Now tell me how to submit this.

[Wanderfound]

I'll make it more Generic, then. Good points.

Make it cost after recovery if you want the spaceplane crew in. My heavy lifter costs √176,000 for a payload capacity of around 50 ton, but the only expense is a few thousand in fuel.

[Firerunner]

Made a quick entry for the light category with a payload of 11.84t. The insights re: costs of solid boosters for career mode were interesting, though I think I'd go with two solid booster stages and a larger recoverable circularization stage in practice. It also had around 600m dV left in the circularization stage in a 100km orbit, so obviously things could be optimized more.

Stats:

Total cost: 36,198

Payload cost:15,460

Lifter cost: 20,738

Payload fraction: 6.0%

Payload mass: 11.84t

Cost per t: 1,751.52

The "Can o' boom" lifter:

[Comrade Jenkens]

Cost per t: 1,751.52

That's way better than what I'm managing. I'm launching at roughly 11,000 per ton!

[bhauth]

Here's something with lower cost but lower payload fraction.

351.476 tons

39.49 tons payload = 11.2%

√45394.5 cost

1149.5/ton

http://i.imgur.com/LLUdyxU.jpg

bhauth.com/files/big_dumb_booster.zip

[Tweety]

So I have an entry which for some reason my I think is good for I can for the life of me figure out payload fractions or cost per ton. Ask me in the morning and I could do it so please humour me for now

I bring you lovely Kerbonauts...

The 1285kg Probe Lifter v2.1 (oh yeah I'm THAT good with names)

Javascript is disabled. View full album

The craft file: https://www.dropbox.com/s/hqex66gu17irhq2/1285kg%20Probe%20Lifter%20V2_1%20%288385K%29.craft

Please tell me if its not working since this is the first time I have used imgur and dropbox (I've had a very long day sorry)

Edit: As promised the math can be done with pen and paper in the morning

Lifter Cost: 4500 (5250 with mechjeb)

Payload fraction: 9.66%?

Cost per tonnage: 3502 (4086 with mechjeb)

I'm sure my calculation are correct but correct me if I'm wrong.

Edited July 24, 2014 by Tweety
I woke up and could do math.

[Camaron]

Make it cost after recovery if you want the spaceplane crew in. My heavy lifter costs √176,000 for a payload capacity of around 50 ton, but the only expense is a few thousand in fuel.

That would create radically different situations. If I did that, I would have to give spaceplanes their own section. It's a cool idea but it would be unfair against traditional lifters. Also, If I'm not mistaken dont the recovered parts yield less than 100% cashback?

Note: In the next few I will be posting the valid submissions into the rankings. There are three valid entries at this point, I believe.

Lastly, I will be converting the scoring to √-per-ton, which would not change ranking at all, but would offer much cleaner scoring numbers than what I had originally proposed.

Edited July 23, 2014 by Camaron

[Wanderfound]

Also, If I'm not mistaken dont the recovered parts yield less than 100% cashback?

If you land on KSC runway, you do indeed get 100% recovery (minus expended fuel). And because my spaceplanes are usually only burning oxidiser for a minute or two per flight, even the fuel bill is tiny.

Kerbal spaceplanes are outrageously cheap to fly. And the 100% recovery thing means that there's no need to economise (apart from crash risk). While everyone else has been working on stripped-back solid fuel budget lifters, I've been tooling around in tricked-out orbital sportscars.

The prototyping ain't cheap, however. I had half a million worth of heavy spaceplanes disintegrate on takeoff before I got the landing gear issues sorted. Fun to watch, though.