An Affordable Space Program: making the reusable spacecraft pay off.

[DerMeister777]

Swifty: Don't give up! Your fleet and operation looks incredibly good. Maybe you could use a docking port on one side of the craft's bay, and then cover the other side with a few KAS struts. They'll take up whatever space is left over and keep the load steady. Just put a KAS container on the top of the payload, drop a Kerbal onto it, and let him attach struts after the payload has been docked.

That's why I made my system so brute force and simple. I don't like moving parts. And I suck at space planes and all...like a lot.

[Swifty]

The problem is not with the reuseable system. It works perfectly. It's with problems such as modules attached to kas winches disappearing. Crash to desktop on removing kas connection ports. And most importantly FAR aerodynamics breaking I.e. It stops calculating to forces on the aircraft making it completely unflyable - it just spins out of control....

If after fighting through KAS bugs (I've kind of worked out exactly what to do to avoid some of the crashes.) I the. Am faced with an aircraft that can no longer fly. So I have to respawn the aircraft with payload attached exactly as I'd done it with KAS everything is fine. But it just seems like a futile waste of effort bring and aircraft back, refuel, load cargo, recover aircraft with cargo, make new one in SPH fly mission, repeat. I've flown 4 modules up now and every time I've had to recover the aircraft and make it again due the FAR bug, and usually I've had to load the cargo twice due to crash to desktop during the loading the cargo....

If it went for all the bugs I'd have finished by now. I'm pleased with my reusable system, but disappointed it's not really reusable due to game bugs :-( I'm going to finish building the station but don't really feel it will qualify as an entry due to the above.

Edit: in summary avoid using KAS FAR combination whilst doing this challenge.

[PyroDesu]

I'll certainly try this one as soon as I get back to my KSP-capable computer, it looks fun (and I love stationbuilding). Might make SirJoab define a new rule or two, though - I plan on using the most Kerbal of launch systems if the correct mod is up-to-date.

[Pyranz]

I'm in the same postition as PyroDesu (I swear we don't know each other, the name similarity and situation is a weird conincidence). I was wondering if you could add a new category that expands on the cost effectiveness them a bit. Seeing as the cost of building the spacecraft is no longer an issue for those on the leaderboard (and it is just a challenge of persistance and computer ability), the focus should be shifted to reducing the massive amounts still spent on fuel. In the new category people can be judged on how much they get into orbit for every mass of fuel used. To work this out you simply add up fuel mass (in the launcher) on launch, and take away what you have when the refuel rover docks. You then divide the score (according to the current system) by the mass of the total fuel used and viola, you have a new scoring system which favours the efficient.

You should be allowed to take away fuel that is left in the space station, because any spare fuel you don't use and leave there hasn't been actually used, and is sort of a payload even if it wasn't intended.

TL;DR: a new, parallel scoring system could work by the equation:

[score on current sytem] / ( [total fuel mass used refueling] - [total fuel mass on station NOT delivered inside a payload] )

You could also have another one again, but it just measures average payload mass.

I don't want to sound bossy, it's just an idea that occured to me when I was reading this thread. I thought it might tackle the issue raised earlier about how any old reusable spacecraft can get huge scores by simply doing enough trips.

[DerMeister777]

I agree. I think there should be two leaderboards however, one for brute force tonnage. (Maybe tonnage per launch or total). Then you'd have a second for fuel efficiency.

[Rakaydos]

Or perhaps one for Refueling Costs per launch... how much does it cost to spawn the tanks you need to refuel.

[sdj64]

I think that the rationale behind the current scoring system not depending on mass of fuel is that fuel is very cheap compared to the cost of building and refurbishing rocket parts, making any rocket that can be reused without having to be recovered and refurbished (by clicking "recover vessel" and relaunching from the VAB) is a significant cost saving. Some quick google searching found that the cost of rocket fuel per launch is only about 5 percent or less of the total cost, though the numbers vary widely depending on the rocket used, of course.

[Damaske]

The Mass Key Shipyard will step up for this and will bring out our own space program. But as CEO Ii have a few questions.

How large is the station needing to be, was not clear on the part size of each section.

From what I've read you must recover any stages that have been dropped during ascent. I've added chutes to my dropped stages yet they vanish once I get X km away from them as in they no longer appear as debris. Nor have I found em on the surface of Kerban. There is also the subject of how to reattach decouples to remake the stack.

[DerMeister777]

Put a MechJeb module on each one and a tiny battery. That might work.

[Rakaydos]

From what I've read you must recover any stages that have been dropped during ascent. I've added chutes to my dropped stages yet they vanish once I get X km away from them as in they no longer appear as debris. Nor have I found em on the surface of Kerban. There is also the subject of how to reattach decouples to remake the stack.

You have to switch back to your booster before it drops below 23km, or the game will delete it. As for reattaching stages, that will require careful docking port engineering.

[gchristopher]

my dropped stages yet they vanish once I get X km away from them

Yep, this is hard. Everything within 2.3 km is still subject to physics simulation and can be switched to control, but farther than that, it goes to "on-rails" physics and will vanish as Rakaydos describes.

It is possible to have a reusable first stage if you find some way to preserve/land it in some combination that also gets subsequent stages away safely. One possible scenario might be to launch nearly vertical then separate stages. If the second stage has a high enough TWR, you might be able to accelerate it fast enough that you can switch back to the first stage, land it, then go to the tracking center and take control of the second stage before it reenters the atmosphere for a circularization burn.

Re: Discussion about different scoring systems:

Since this challenge is all about exploring neat designs that might matter in a future version of an unfinished game with regards to a economics that don't exist yet, pretty much any scoring system is going to be speculative and premature. I think it'd be okay to present attempts in the order completed, like the K-prize, or maybe try to categorize them?

The real point is:

A. You did it. This thing is HARD.

B. Whatever interesting/fun bits you discovered/created along the way.

I see SirJoab has already added little highlights of what each person did to the first post. That was going to be my only suggestion to change!

• Kasuha's system of chaining docking ports to create a flexible fuel line/anchor to align payloads with the VTOL lifter deserves a mention.
  
• Jasonden presented the first VTOL lifter to not use jets. (With the million 24-7S engines)
  
• 1greywind boasted a quick 22 minute fastest mission turnaround (wow) that must have made those 12 missions a lot less tedious.
  

[Pyranz]

I know any scoring system is going to be entirely speculative, but the issue is that currently it's based off of the total mass of what you have left in orbit. It doesn't encourage efficiency, which is ultimately the spirit of the challenge. And yes, managing to complete this is a major achievment, but everyone who has got a score has made this achievement, so that's why it's there, to compare the elite few who did it.

As for the fuel only being 5% of the total cost of a mission: that 5% is still a huge cost. And if you're using 10 tonnes of fuel for each tonne in orbit, you're still spending a lot of money.

[Rune]

@gchristopher:

I actually did most missions in the absolute minimum amount of time for a winged SSTO: I reloaded the SSTO as the station went around kerbin, launched as it came into the horizon to a direct rendezvous, go with it for half an orbit and land back at KSC to repeat the process: when you do the same thing more than ten times, then you repeat the whole thing, you get really, really good at it. In the end, the total construction time for my second station was very close to 9 orbits to drop 9 modules times around 30 minutes for each... 4.5 hours total click time. I expect a bit more since some other mission alarm clock is bound to have come up, but my kerbals set up their stations in a single work day.

As to scoring, I've already said it a lot of times, but it is at least consistent: the SSTO with the most payload capability gets the biggest score unless the other guys compensates with proportionally more flights. And even then there's the limit of bugs and patience, so no one is going to go much over 10 flights. Too late to change it now, and the "special comments" section with links to the entries allows all newcomers to make their own opinions. Just consider the leaderboard a payload comparsion.

I am seriously tempted to try this yet again with the newer, bigger brother of the Broadsword (x3 payload capability) and pulverize my record, both on efficiency and tonnage, only the "station" would be an ugly mess of orange tanks. Then again, as a depot to get fuel to move 'roids around...

Rune. Take that, ISS, with your 10+ construction years!

[Pyranz]

Getting massive payloads to orbit without staging is easy. Landing those launchers in ksc I easy once you know how, even more so now that parachutes can deploy one at a time. The new NASA update make stable crafts really easy with the bigger parts and the magical number "7" being changed. A wide skycrane with enough jets can lift any payload (provided it's not too fragile) and place it carefully on the landed launcher. A docking port on the side of the craft allows any wheeled rover to attach if you get the docking port positioned well for refueling.

There are so many genius ideas on this thread that score lowly because the result is the same as the person who made the unstaged Saturn rocket with parachutes.

The scoring is based too much on the final product, not the creation method. A space station costs the same on the ground no matter what. It's getting it into space that you're trying to reduce.

There should be categories for best efficiency, easiest turnaround, versatility, etc. Not best station in orbit.

@ Rune

Do the new broadsword! The last one was amazing and I know I'd love to see how it got even better.

[SirJoab]

...There are so many genius ideas on this thread that score lowly because the result is the same as the person who made the unstaged Saturn rocket with parachutes.

The scoring is based too much on the final product, not the creation method. A space station costs the same on the ground no matter what. It's getting it into space that you're trying to reduce...

I agree, but when I started this challenge I had no idea it would take on such a large and exotic scope! I'm trying to come up with a scoring system (and leaderboard) that would give more recognition to the enormous efforts and genius systems I have been seeing, but that's a difficult task! All I can say is keep it up guys, your stuff is amazing.

[Tarantulae]

I'm working on this, but have a question. You sadi the modules must be flown one at a time. Due to ground clearance issues, I'm designing a ship that carrys 2 modules at once, which then dock once in orbit. Would they count together as "1 module" or 2 since they are docked together?

It doesn't really matter I guess, but I was just curious.

[SirJoab]

They would count as one module... The rule could have read 'at least four round-trips' but I thought it would be simpler to define that as 'modules' rather than 'trips'.

[kmMango]

I believe cupcake did just that with one of his part-clipping super-VTOLs

[kmMango]

Ah, so much ingenuity. I never thought anybody would actually REUSE their reusable SSTOs.

[Fengist]

Been looking at this challenge since it came out and been testing ideas when I have time. I've seen a lot of you guys coming up with some pretty creative stuff and felt compelled to do something different.

Unfortunately, this is not an official entry. I simply don't have the time to deliver all the modules. RL sucks. However, I did get an RCS tug into orbit and I loaded before I launched to make sure loading was possible. I also landed back at KSC and started refueling my SSTO... erm VSSTO that is. So. In essence, my methodology works. It's just a lack of time to complete this. I may get some time in a few weeks and if I do, I'll send up a few more modules. In the meantime, it may provide some inspiration and some ideas. The only thing else I'd like to add to the ground crew is some sort of mobile platform that I can move up to the docking port so that I can use KAS struts to lock down anything I attach to it.

My SSTO is a VTOL. It's a design I came up with working on my VTOL challenge which I named Starfish. 6 SABRES (Rapiers cost me lots more fuel), 6 Turbofans, (to help get it off the ground and they're super efficient for cruising. Their spool time sucks so landing a VTOL with them is rough.) and 2 Atomics for orbital maneuvers. It has a flight crew of 2 and accommodations for an additional 2 Kerbals.

Bunch of screen shots, hope you like looking at pics. Enjoy.

Here I'm moving the Starfish2 from the VAB to a more centralized location.

A fuel tractor parked beside Starfish2

And here I'm using KAS for the refueling

And the cargo tractor.

Using a gantry to unload an RCS tug from the cargo tractor. The plan is to drop it straight down onto the Starfish's docking port. In case you're wondering, the tug is about 9 tons.

Ok, this sucks, the gantry is too short.

Solution? Build a bigger gantry.

Departing KSC

Another departing shot. Note both the SABRES and the turbofans are running.

Rear shot of the Starfish2. You may notice 4 rear facing air intakes. Found they come in handy when landing a VTOL.

RCS Tug solar panels deployed, ready for separation

Frontal shot after deorbit burn. The pink diamond is the RCS Tug

Night landing at KSC. Note: Only using the turbofans to land. Was running way low on fuel but that's exactly why I mounted them. Even with all 6 running, from deorbit burn to ground, I only used 13 LF. Unfortunately, they crap out at 13,000m or speeds above 350ish.

And fueling back up

Oh, and because I made it back with so little fuel (My SABRES flamed out and took me a gob of fuel to regain composure.) I HAD to deliver at least one more module just to see if this VTOL could catch up to an orbiting station and still land. It did with 775 LF left.

Edited April 26, 2014 by Fengist

[gchristopher]

I don't recognize a lot of the parts, but Starfish looks pretty cool! You know, you could have an awesome finished entry in two more flights, Fengist.

[Hodo]

Looks like bulk of the Starfish is B9 parts, there is some KAS in there, and the tracks mod, I can't remember the name of it.

[Fengist]

Mostly B9, stock and RBI tracks. I'll work on getting some more mods up in the next few days.

[Fengist]

Ok, I managed to find time to complete this challenge. Since I was going more for, can I do it, rather than a score, don't expect much in that department. In my previous post, I mentioned that I was pondering a way to get a Kerbal up to the clampotron that holds the cargo so I could bungee it down with some KAS struts. Well, I found a way to do it and in true Kerbal fashion, I went waaayyyy overboard. I made an elevator. I could explain how it works but you wouldn't believe me. So, I decided a video would give the full, 'OMG this man has lost his mind' affect.. Below that are a few more shots including an updated fuel/elevator truck I used for the final launch.

+5 Kerbals,

-3 refuelings

+4 modules

26 tons total

Score, 32 - barely passable.

Oh, and mods used:

B9, lots of B9

KAS, obviously

Multi-wheels (the tailgear from this mod are the bearings for the elevator)

RBI Tracks

Ion Pack (I used generators from this mod on the gantry and the tractors to power the winches. None are on the Starfish or the station)

Edited May 4, 2014 by Fengist

[SirJoab]

Beautiful! I really like the Starfish. Very Sci-Fi.

Here's your score:

+4 for 4 Modules

+26 for 26 Tons

-3 for 3 refuels

+5 for 5 Kerbals

+2 for style.

Total: 34 points.

I love the use of KAS, you really made this mod pay off.