The Cheap and Cheerful Rocket Payload Challenge 1.0.5

[SanderB]

(1,590 + 3,700)/6.389 = 828$ / t if my calculations are correct, which if they're not they can be recalculated with the numbers KER shows. No tail fins, 80km orbit. I think this is it. Launching it is pretty simple once you have it tilted correctly in the VAB; launch, stage at burnout, maintain prograde (20 degrees) minimum pitch, circularize at 80km and separate payload. The tilt is the hardest part to design because the slightest change results in drastic differences to the ascent profile. If you change the payload only a little, everything changes.

My design can be currently gotten here: http://www.filedropper.com/03expendablelauncher

If I'm not mistaken this design is the most cost/t efficient for of all the vehicles with a 1.25m cross section (even though there is not a separate leaderboard for them as far as I know). There is space for a bit more efficiency but I didn't want to spend the time to fine tune it THAT much.

[Norcalplanner]

8 hours ago, Streetwind said:

Alright, I'm currently strapped for time at home, so forgive me for a bare minimum submission.

The "25 Science Lifter" in the VAB. The side-mounted SRBs are throttled to 72.5%, the center is 100% (this smoothes out the TWR curve). Surprisingly enough, this thing doesn't noticably wobble even without KJR installed. Lifter cost is 2,950 + 3,800 = 6,750 funds. Payload is 2,458 funds. Total cost is 9,208 funds.

The payload in orbit. It's an arbitrary mass simulator, not constrained by the tech limit the lifter has. It has an engine though, since this challenge heavily favors using the payload to contribute dV. That's why I didn't use one of the common booster setups I displayed before - those would simply not have the TWR to increase the payload further, even if the payload could contribute dV.

Payload contributed 4,616 - 4,142 = 474 m/s dV. Final mass in orbit is 7,006 kg out of an initial 8,060 kg. Periapsis altitude is 80,020 m.

Score comes out at 6,750 / 7.006 = 963.46 funds/ton, showing that it's quite possible to get into the triple digits even with only General Rocketry unlocked

 

Great rocket, Streetwind.  I like that you've come up with something that's cheap and accessible very early in career.  A little thin on the entry documentation, but I've been there IRL, so I understand.  Putting you on the leaderboard shortly.

[Norcalplanner]

Slashy,

I knew you couldn't let it stay above 900 funds/ton.  I look forward to whatever else you come up with.  Adding you to the leaderboard.

[Norcalplanner]

Nicely done, SanderB.  You're definitely the 1.25 meter leader, and also have the distinction of having the lowest absolute price for any lifter entered so far.  I learned a thing or two from your ascent profile, too.  Adding you to the leaderboard.

[Norcalplanner]

So I decided to make a craft just for this challenge.  The basic Orange Tank Refueler design got scaled up, with 1.5 more orange tanks added to the payload.  The lifter consists of a Mainsail sustainer with 16 Kickbacks on four radial decouplers.  Nose cones on the Kickbacks are omitted to hold down the cost.  I stole a page from some other entries and beefed up the reaction wheels in the payload to make it easier to turn.  In the end, we have the biggest challenge payload so far, and the first time ever that I've personally managed to crack the 800 funds/ton barrier with a rocket for a challenge.

Final score: 76,800 funds to lift 96.22 tons to orbit equals 798.17 funds/ton.

Full info is in the descriptions in the album.  Enjoy.

 

[Nich]

Well I wanted to see if the expensive engines could pay there weight and I have to say no.  I was not able to break 1000/ton until I "cheated"

157 dv left before I decoupled the tanks

no fuel used from the payload (I just realized I could have used 500 dv)

Total cost 138260

Payload cost 58220

Payload to orbit 136.26 tons

Giving 587 kerdits/ton

Even if you add the cost of the engine it is still only 770/ton so nothing to be ashamed of

 

HAHA did you enjoy your minute on top?

[Norcalplanner]

27 minutes ago, Nich said:

Well I wanted to see if the expensive engines could pay there weight and I have to say no.  I was not able to break 1000/ton until I "cheated"

157 dv left before I decoupled the tanks

no fuel used from the payload (I just realized I could have used 500 dv)

Total cost 138260

Payload cost 58220

Payload to orbit 136.26 tons

Giving 587 kerdits/ton

Even if you add the cost of the engine it is still only 770/ton so nothing to be ashamed of

 

HAHA did you enjoy your minute on top?

Nich, very creative staging.  Reminds me of that one Saturn V MLV variant which never got built that had four giant SRBs with liquid fuel tanks on top of them, feeding the central S-IC. 

However, I can't place this on the leaderboard yet.  The rules for the challenge are clear that an engine which is part of the payload can only add up to 500 m/s of delta V to the final orbital insertion of the craft, and only after detaching from the lifter.  While I don't have any clear indication of how much delta V that Rhino contributed, it looks like it drained four orange tanks, which was likely a lot more than 500 m/s.  To put it another way, asparagus staging (which your craft uses a variant of) isn't going to be allowed by the challenge rules because the center stack fires while still attached to the rest of the lifter, and provides a lot more than 500 m/s of delta V. 

That said, your basic design could be retained and still comply with the rules if you place the Rhino on a decoupler and stage it at the end, so that it's no longer part of the payload.  Unfortunately, that would reduce your payload mass by 9 tons and increase your lifter cost by 25,000 funds, which would affect your score.  Feel free to submit a revised design that complies with the rules. 

Again, full props for creativity, but this craft as it currently stands doesn't quite comply with the rules for this particular challenge.

[Temstar]

Since I'm known for big rockets and asparagus staging it would be remiss of me to not represent the vegetable growers in this challenge

Spoiler

The completed launch vehicle: Nova IIC with payload in the VAB. Total cost $327,320. Yes this is as far back as I can zoom out.


The payload, $87,270 on its own. So that means the launch vehicle is 327320 - 87270 = $240,050


Launch! That's just under 15,000kN (already compensated for atm Isp) of thrust coming out of the bottom of that rocket, or in another words, more than twice as powerful as the real life Saturn IB

First pair of boosters jettisoned at T+33.

Second pair of boosters jettisoned at T+1:17


Last pair of boosters jettisoned at T+2:22. I sure got my bang for my bucks with those two engines, look at them glow!
 

Main engine cut off at T+4:13. Payload delta-V is 6,422m/s.


Payload hot staging from booster core and beginning orbital insertion burn.


Payload coasting to AP after desired AP achieved.


Orbit immediately after payload insertion burn. Note that AP is on the other side of the planet more than 12 minutes of coasting away.


Payload circularisation burn at AP.

80km x 80km orbit achieved. Final payload delta-V is 6224m/s. 6422 - 6224 = 198m/s of delta-V spent by payload. Final payload mass to orbit is 262.50 tons.

$240,050 / 262.50 tons = $914.48 per ton to orbit. Not bad for all liquid rocket right?

Let's see, features of this rocket: I carried more payload to orbit than the current top seven entries on the leaderboard combined.

 

Edited January 28, 2016 by Temstar

[Nich]

Ok so here is my retry.  It really sucks compared to the previous entry

Did an absolutely perfect gravity turn too and it was so easy just turned to 15 degrees and turned off SAS until SRB ran out then followed prapagrade 

123.38t

Total Cost 130794

Payload Cost 37120

DV used out of the payload 158

759 funds/t

 

[Norcalplanner]

Temstar and Nich,

Two very nice looking entries, both breaking out the 3.75m parts and using fuel crossfeeding.  I'll look at these in detail later today when I'm not on my phone.

[GoSlash27]

Norcalplanner,

 FWIW, I'd recommend a change to the rules where the apoapsis must be at least 80km, the periapsis must be at least 1m, and the payload may not provide any DV. This would remove the problem with "gaming" the payload.

 As it stands, I believe i have a design that can break the $700 barrier within the current rules.

Best,
-Slashy

[Norcalplanner]

5 hours ago, GoSlash27 said:

Norcalplanner,

 FWIW, I'd recommend a change to the rules where the apoapsis must be at least 80km, the periapsis must be at least 1m, and the payload may not provide any DV. This would remove the problem with "gaming" the payload.

 As it stands, I believe i have a design that can break the $700 barrier within the current rules.

Best,
-Slashy

Slashy,

Thanks for the suggestion.

By my reckoning, the idea would essentially reduce the payload contribution to less than 100 m/s. While many folks on the forums wouldn't have any problem designing and flying a craft like that, it would likely scare away some players of intermediate skill. With the current leader not using any thrust from the payload, I'm also not sure that there's a need to tighten up the rules at this point.

I'll keep this idea in my back pocket with the others, ready to bring out if there starts to be a problem.

And I look forward to your new entry. :-)

Edited January 28, 2016 by Norcalplanner

[GoSlash27]

Norcalplanner,

 Here it comes!

The Cheep 18 lifter stack. 3 Kickbacks for the booster and a Poodle for the transstage.

Cost on the pad is $29,050

Cost of the payload is $17,300. This leaves $11,750 as the cost of the disposable stages.

Mass at the start of circularization is 20.09 tonnes.

Mass at end of circularization is 18.05 tonnes.

Isp of payload engine is 340s.

DV expended by payload is 340*9.81*ln(20.09/18.05) = 357 m/sec.

Expended cost is $11,750/ 18.05t = $650.97 per tonne.

I seriously think this is about the best I am capable of doing. I relied heavily on "gaming" this entry. A more realistic insertion stack based on this design would be more expensive, but still under $800 per tonne.

Best,
-Slashy

Edited January 28, 2016 by GoSlash27

[Norcalplanner]

Is that explosive decoupling I see? Wow, you really did game it on this one. I'll look at it in detail tonight.

[maccollo]

I will not let this stand! I must admit though, explosive staging was pretty neat. After seeing that I decided to use that too for my next entry because I thought I might be able to breach 600 funds/ton. I didn't, but I am only 0.4 tons away from doing it, so it might perhaps maybe be possible if I pull of a perfect launch.

Total cost: 87581 funds
Payload cost: 26319
Launcher cost: 61262
Payload mass in LEO: 102.6 metric tons
Funds per ton: 597.1
 

VAB screen dumbs:
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/launcher3.png
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/payload3.png

Launch video:
https://www.youtube.com/watch?v=_QRPhFu9d04

Edit: turns out I did crack 600. Counted the payload engine into the cost of the launcher, and therefore got a higher cost/ton value than I actually had.

Edited January 29, 2016 by maccollo
Accounting error

[GoSlash27]

16 minutes ago, maccollo said:

I will not let this stand! I must admit though, explosive staging was pretty neat. After seeing that I decided to use that too for my next entry because I thought I might be able to breach 600 funds/ton. I didn't, but I am only 0.4 tons away from doing it, so it might perhaps maybe be possible if I pull of a perfect launch.

Total cost: 87581 funds
Payload cost: 25019
Launcher cost: 62562
Payload mass in LEO: 102.6 metric tons
Funds per ton: 609.8
 

VAB screen dumbs:
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/launcher3.png
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/payload3.png

Launch video:
https://www.youtube.com/watch?v=_QRPhFu9d04

Outstanding!

 You hit on the same concept I was looking at last night; semi- asparagus staging. You use SRBs for propulsion while lifting drop tanks to feed the central core.

I couldn't make it work, but it looks like you've got it wired.

Congrats!

-Slashy

 

Edited January 29, 2016 by GoSlash27

[Meithan]

Impressive, @maccollo. So the "drop tanks", as Slashy calls them, empty before the SRBs burn out, right? How soon before (can't see video at the moment)? Because you're carrying empty tanks from that point until the SRB clusters separate. Why not use proper drop tanks?

In fact, why haven't we seen more asparagus designs? For rockets in that payload class, a radial decoupler and a fuel line are almost insignificant in terms of cost and mass. I guess it adds up?

Edited January 29, 2016 by Meithan

[maccollo]

@GoSlash27
It turns out I made an accounting error. I counted the payload engine into the cost of the launcher. When I corrected for that the cost/ton was just barely under 600, so I wont have to refly this thing over and over again to get a slightly more efficient launch. Hurray!

Edited January 29, 2016 by maccollo

[GoSlash27]

1 minute ago, Meithan said:

Impressive, @maccollo. So the "drop tanks", as Slashy calls them, empty before the SRBs burn out, right? How soon before (can't see video at the moment)? Because you're carrying empty tanks from that point until the SRB clusters separate. Why not use proper drop tanks?

In fact, why haven't we seen more asparagus designs? For rockets in that payload class, a radial decoupler and a fuel line are almost insignificant in terms of cost and mass. I guess it adds up?

Meithan,

 Thus far, no LF&O engine can hope to compete with solid fuel for cost- effectiveness. There may be a true asparagus design that can keep up in terms of "bang for the buck", but if so it's likely to be a very large lifter.

Best,

-Slashy

[Norcalplanner]

Gentlemen:

First, I finally found the link for the real proposed craft which used that technique of putting fuel tanks on top of radial SRBs - the Saturn V/4-260.  Check out the specs in the link - I get giddy thinking of what we could have done with that kind of lifting ability had the craft been built.

Second, I've come to the unfortunate conclusion that I have to put my foot down on the issue of explosive staging.  I know that this is KSP, not real life, but it's hard to simultaneously encourage a real-world responsible launch profile (small amount of delta V from the payload) while also allowing a completely unrealistic and near-suicidal staging system that nobody in their right mind would ever use IRL.

Therefore, I am amending the rules to specify that all staging must be done via a decoupler, stack separator, or docking port.  No further entries with explosive staging will be allowed.  Existing entries which have used explosive staging will be put on the leaderboard, but they're going to get the Barry Bonds asterisk treatment and be put in a special section.

Sorry to have to take the step, but one of the ideas with this challenge is to help equip KSPers with practical design ideas and good launch habits. 

[Norcalplanner]

11 hours ago, Temstar said:

Since I'm known for big rockets and asparagus staging it would be remiss of me to not represent the vegetable growers in this challenge

  Hide contents

The completed launch vehicle: Nova IIC with payload in the VAB. Total cost $327,320. Yes this is as far back as I can zoom out.


The payload, $87,270 on its own. So that means the launch vehicle is 327320 - 87270 = $240,050


Launch! That's just under 15,000kN (already compensated for atm Isp) of thrust coming out of the bottom of that rocket, or in another words, more than twice as powerful as the real life Saturn IB

First pair of boosters jettisoned at T+33.

Second pair of boosters jettisoned at T+1:17


Last pair of boosters jettisoned at T+2:22. I sure got my bang for my bucks with those two engines, look at them glow!
 

Main engine cut off at T+4:13. Payload delta-V is 6,422m/s.


Payload hot staging from booster core and beginning orbital insertion burn.


Payload coasting to AP after desired AP achieved.


Orbit immediately after payload insertion burn. Note that AP is on the other side of the planet more than 12 minutes of coasting away.


Payload circularisation burn at AP.

80km x 80km orbit achieved. Final payload delta-V is 6224m/s. 6422 - 6224 = 198m/s of delta-V spent by payload. Final payload mass to orbit is 262.50 tons.

$240,050 / 262.50 tons = $914.48 per ton to orbit. Not bad for all liquid rocket right?

Let's see, features of this rocket: I carried more payload to orbit than the current top seven entries on the leaderboard combined.

 

Great job, Temstar.  Best LFO entry so far, and it's nice to see a little 3.75m love.  Putting you on the leaderboard.

[Temstar]

I think I might have conceived a way to abuse the current rule set as it stands, and no it doesn't involve explosive staging. Will try to get the design to work tonight. It's making use of the old "payload vs upper stage" grey area thing again.

But yeah seen as you've already made a precedent for rule change, I suppose there's always the opportunity for more rule changes to fix rule lawyering / creative accounting.

[Norcalplanner]

3 hours ago, GoSlash27 said:

Norcalplanner,

 Here it comes!

The Cheep 18 lifter stack. 3 Kickbacks for the booster and a Poodle for the transstage.

Cost on the pad is $29,050

Cost of the payload is $17,300. This leaves $11,750 as the cost of the disposable stages.

Mass at the start of circularization is 20.09 tonnes.

Mass at end of circularization is 18.05 tonnes.

Isp of payload engine is 340s.

DV expended by payload is 340*9.81*ln(20.09/18.05) = 357 m/sec.

Expended cost is $11,750/ 18.05t = $650.97 per tonne.

I seriously think this is about the best I am capable of doing. I relied heavily on "gaming" this entry. A more realistic insertion stack based on this design would be more expensive, but still under $800 per tonne.

Best,
-Slashy

Slashy,

Very creative, and a great score.  As I indicated above, I've made the call to prohibit any further explosive staging entries, so this wonderfully low score will go in the asterisk section of the leaderboard.

[Norcalplanner]

1 hour ago, maccollo said:

I will not let this stand! I must admit though, explosive staging was pretty neat. After seeing that I decided to use that too for my next entry because I thought I might be able to breach 600 funds/ton. I didn't, but I am only 0.4 tons away from doing it, so it might perhaps maybe be possible if I pull of a perfect launch.

Total cost: 87581 funds
Payload cost: 26319
Launcher cost: 61262
Payload mass in LEO: 102.6 metric tons
Funds per ton: 597.1
 

VAB screen dumbs:
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/launcher3.png
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/payload3.png

Launch video:
https://www.youtube.com/watch?v=_QRPhFu9d04

Edit: turns out I did crack 600. Counted the payload engine into the cost of the launcher, and therefore got a higher cost/ton value than I actually had.

maccallo,

Very impressive achievement - I didn't think that anyone would be able to get below 700 funds/ton, let alone 600 funds/ton.  Well done.  As I stated above, I've made the call that future entries cannot use explosive staging, so you are now (and possibly forevermore) the winner of this particular challenge.  Your score will be placed at the top of the asterisk section of the leaderboard.

[Norcalplanner]

47 minutes ago, Temstar said:

I think I might have conceived a way to abuse the current rule set as it stands, and no it doesn't involve explosive staging. Will try to get the design to work tonight. It's making use of the old "payload vs upper stage" grey area thing again.

But yeah seen as you've already made a precedent for rule change, I suppose there's always the opportunity for more rule changes to fix rule lawyering / creative accounting.

If you're thinking about running fuel lines from the payload to the lifter so that they're not counted towards the cost of the lifter, but you get to count the empty fuel tank mass as part of the payload, then I'm afraid I'll need to put on the black hat again.  The intent is for a small, realistic circularization burn, not for launching an empty fuel depot.  If that was the intent, then the rules would allow for SSTOs to remain in one piece, as Nefrums asked about back in the second post.

I think I'll preemptively clarify that particular rule.