RSS/RO/RP-0 Get to orbit under 40T with the least amount of unlocked nodes

[John FX]

Simple challenge, very similar to ones that have been done before except this one is in Realism Overhaul /Real Solar System using Realistic Progression Zero.

The idea formed when I was playing career and needed to get an artificial satellite in orbit but only had a very limited amount of money and the basic launchpad. I needed to do it under 40t and tried very hard but due to tech limits (and controlling my craft with remotetech issues meaning I had no control in some places) I failed.

But only just.

So I thought about making a challenge to get into orbit under 40t but then I realised that with later tech it was probably quite easy so then I thought the challenge should be along the lines of what is the smallest amount of nodes you need to unlock in an RP-0 career to be able to get into orbit with the first launchpad (40t limit)?

So rules.

You must launch from the starting launchpad in Cape Canaveral, Florida, you must get to an orbit with a Pe of at least 140km.

No cheat menu except to show thermal info etc

Mechjeb allowed, this is a design challenge not a pilot challenge

You are allowed to add as much starting science as you like to unlock nodes, this is not an exercise in grinding. Be aware though that the more nodes you unlock the higher your score will be so choose carefully.

Anyone attempting to `game the rules` and find exploits will be excluded from the challenge. No infiniglide, kraken drive, ladder drive or similar (are those even things any more? I seem to remember bugfixes that dealt with a few of the exploits)

Most important, the part packs allowed (especially engines and tanks) are limited to the required ones that come with RO and the recommended mods (as CKAN defines them) not the suggested ones.

scoring

Your score will be the weight in tons on the launchpad multiplied by how many nodes you have unlocked in career. This means lower tech will usually beat lower weight.

Lower score is better. The maximum score is 40 tons x every node unlocked which looks to be around 150=6000

The minimum would be a single node multiplied by your weight which is limited to 40t so assuming a 40t craft your score would be 40

The node you start with counts as 1 node or the scoring would get silly.

ADDITIONAL RULE

Your score will be divided by your payload in tons to reward those who put more into orbit.

This means a single node, 40T on launchpad and a 2T payload would score (40x1)/2 which would be 20

 

Let me know any glaring omissions or any questions and above all, HAVE FUN!

 

SCOREBOARD

1, @Laie 2 nodes x 40T/0.75=107 points

2, @NathanKell 1 node x 39.049T/0.084=464.86904

3, @Teutooni 3 nodes 23T/0.085=545.78823

4, @a_schack 2 nodes x 32.025T/0.062=1033.06452

5, @Phineas Freak 4 nodes x 30.454T/0.019= 6411.36842

6,

7,

8,

9,

10,

 

As is the done thing I should relate my attempt, my submission was a failure, I nearly did it but I was about 300Dv short.

 

Edited March 22, 2016 by John FX
added new scores

[winged]

I remember that I've managed to build really silly, 6t rocket with RL10 as a core stage and high-tech (level 7 or so) )Procedural SRB as boosters. Payload ~10kg. However this would require many many tech nodes to unlock all components.

Vanguard -like, 10t rocket should be really easy to do with early tech.

 

Quote

needed to get an artificial satellite in orbit but only had a very limited amount of money

Low mass doesn't mean that it will be cheap, for example my silly 6t rocket was very expensive compared to heavier launch systems with the same capabilities.

[Phineas Freak]

@John FX i think that 40 tonnes are a lot for early orbital. Juno I had a GLOW of approximately 30 tonnes for orbiting Explorer 1 and Vanguard was 1/3 of that.

With only the minimum mods required for RO/RP-0, you need to unlock at least 3 nodes (Early Orbital Rocketry for the engines, Basic Construction for the "Default" procedural tanks and Basic Avionics for the Vanguard probe core). The tank upgrade could be considered as optional if you are willing to accept the increased inert mass of the "Fuselage/ServiceModule" type tanks.

Edited March 12, 2016 by Phineas Freak

[John FX]

5 hours ago, winged said:

I remember that I've managed to build really silly, 6t rocket with RL10 as a core stage and high-tech (level 7 or so) )Procedural SRB as boosters. Payload ~10kg. However this would require many many tech nodes to unlock all components.

Vanguard -like, 10t rocket should be really easy to do with early tech.

 

Low mass doesn't mean that it will be cheap, for example my silly 6t rocket was very expensive compared to heavier launch systems with the same capabilities.

And now you hopefully see why this is an interesting challenge. Sure it`s easy to get into orbit with a small rocket later in the tech tree but each node multiplies your score and so unlocking too many nodes is a losing move.

The financial cost of your rocket is not part of your score, it was just part of the events that lead me to think of this challenge.

I will look forward to your submission.

@Phineas Freak it is a lot but the lower you go with the least amount of unlocked nodes the better your score. It`s not a `can you do it` because it is totally possible, it`s how low can you go...

[Ravenchant]

You need Early Avionics and Early Orbital Rocketry at most. My entry would be disqualified due to Taerobee fins (and launching from Woomera), but 37.7 tons using a RD-103, AJ10-37 and three Baby Sergeants sends the 10-kilogram probe into orbit with some delta-v to spare

[Phineas Freak]

A simple entry, no fancy stuff.

Required tech nodes:

• Early Orbital Rocketry (RD - 103 engine)
• Basic Construction ("Default" procedural tank type)
• Basic Avionics (late Vanguard probe core)

1. Launch Vehicle:

Spoiler

The vehicle is modeled after a combination of the R-5 Pobeda and WRESAT and follows the same launch profile as with the Explorers 1-5.

The first stage is powered by an RD-103 engine, burning Ethanol (75% concentration) and liquid Oxygen (similar to the American NAA- 75-110 that was used on PGM-11 the Redstone). The second stage is a cluster of 12 Baby Sergeants and the third stage is a cluster of 4 Baby Sergeants. Small RCS pods (mounted on the instrument unit) provide 3-axis control and spin-up before second stage ignition.

The vehicle overall has enough payload capacity for approximately 35-40 Kg.

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2. Launch:

Spoiler

Just awaiting for the roll-out and sunrise!

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And we have a launch!

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The fins on the booster stage allows the rocket to remain naturally stable after launch (so stable that you actually have to initiate a gravity turn almost immediately after launch). After that, it can fly itself to orbit.

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MECO! We will wait a bit more before separating the IU (until it has passed 110 km, RCS cannot handle large aerodynamic loads).

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Separation of the second stage and the payload fairing. It will coast to apoapsis before igniting the Baby Sergeants.

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3. Orbit:

Spoiler

Before second stage ignition, the IU spins up to passively stabilize it for the rest of the flight.

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Separation and ignition of the second stage.

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Separation and ignition of the third (and final) stage. The payload will face some really high G forces but it is designed to withstand them without any problem.

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And we have an orbit! A bit wonky but for our first satellites getting them to orbit is our top priority.

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Edited February 14, 2019 by Phineas Freak
Remove images

[John FX]

Nicely done. Maybe I have underestimated the possibilities of the early game, hehe.

@Phineas Freak A weight of 30.454 multiplied by the three nodes gives you a score of 91.362

@Ravenchant Your entry would have been 37.5*2 which is 75 and would put you in the lead. I don`t think the fins make too much difference but you would need to launch from cape canaveral as it is only fair for everyone to have the same Dv requirements.

 

EDIT : Do you think that I should reduce the weight limit to encourage more `inventive` designs?

Edited March 14, 2016 by John FX

[Teutooni]

Made this vanguard-esque rocket carrying a 85-kg sputnik-ish thing to orbit. It is a bit of a tricky one to fly. Needs pretty decent gravity turn and the last stage is this silly solid booster stack with no guidance and 20-45 TWR - in order to get to orbit, it needs to point exactly prograde and be fired at apogee almost to the second. Still, it's just 23.4t and needs 2 nodes unlocked, I believe that is a score of 46.8? The real vanguard had only a few kg payload I believe, which could bring total weight down to historical ~10 tons. However, I thought it would kinda break the spirit of the challenge to send a structural part or something, so I took a lot more massive thing that beeps...

 

Oh and btw I hope procedural fuel tanks are ok? They are not strictly required by RO I believe...

 

Edited March 14, 2016 by Teutooni

[Ravenchant]

Now that I remember, @NathanKell did it without unlocking anything. If it's still possible to do, that may be the winning strategy

[NathanKell]

That design will likely have its engines shut down/exploded/etc by TestFlight for going over the burn time limits (the core and the first WAC upper). However, slightly shrinking the core and switching to air-lighting might (might!) be possible, although the dynamic pressure at core ignition might be prohibitive. You would also have to go to 3 WAC stages to keep their burn time low enough. Increasing delta V would also be possible, perhaps, by having only 1 Starting guidance unit on the core and then 1 each on the boosters. More expensive but the savings in core dry mass might make up for it.

 

It should be very possible to do by unlocking only 1 node, early avionics. That will lower the payload to orbit's dry mass (over the above example) enough to require a much smaller LV and perhaps only 1 WAC stage.

[Laie]

Maybe it's just too late for me to grasp it, but why do lighter rockets score less?

[NathanKell]

@John FX I suggest some sort of normalization for payload fraction. (Otherwise a tier 0 rocket that gets 60kg into orbit, since that's about the minimum payload, will not score more than a Vanguard that gets 8kg into orbit.)

 

Now, a quick followup. Here's a remade "Mirak" that I haven't tested yet, but will probably work.

There's a bit more I could shave off probably, and I also might need to add some solids to the upper for ullage--there may have to be a coast period. But at ~100m/s more than the prior version, and 1.2t to play with, it should be ok. This is with avionics per booster btw.

All tier 0, AFAICT, so that should be the thing to beat.

[NathanKell]

Update: So, it took some tricky flying, but I did manage it. Crashed KSP tho. >.>

Changes to the above rocket:

1. You have to light the core a couple seconds before booster burnout or drag will de-ullage you. That is at a survivable Q however if you use the MJ turn 90m/s start, 80km end, shape 60.

2. Added two small seps tot he lower of the two wac stages.

3. Modified upper staging sequence: Seps and decoupler/shrouds fire, then the lower wac stage lights. The upper wac stage lights and decouples at the same time (although you could light it a second early if you were being very careful).

Also, the flying is a bit tricky, because by the end of the core burn you need to keep level with the horizon but also use the A-4's thrust vanes to spin up a bit to keep that attitude stabilized, because you'll coast for about a minute and thirty seconds before separation and apogee kick (50s to apogee, where apogee was 160km for me on that flight before kick).

When I have a minute, after dinner, I'll refly it with a shot in orbit.

[NathanKell]

It's after dinner. Here's the result.

 

 

Now, if I had managed to keep closer to 0 degrees pitch (probably more like -1 at burnout so during coast it would raise to 0), and precess slightly less, that would be a perigee closer to 160km than what it is. But I'll take it.

 

Oh, and note: This is a risky LV. TestFlight will make something in it fail probably 50% of the time. But all engines are within their specified maximum burn times (or over by a half-second), and the air-lighting is workable even with TestFlight lowering air-light ignition chances (I tested).

One other note: This could be made rather easier to fly by adding a tiny nitrogen tank and some nitrogen attitude thrusters to the core. As the final orbit proved (flown by 90m/s start, 80km end, 60% shape, and Limit AoA to 3 degrees) there is breathing room in terms of delta V, so decreasing the mass ratio of the core slightly by adding some nitrogen (in a heavy tank >.>) and some thrusters wouldn't prevent orbit. And it would make aligning for kick far less finicky.

[John FX]

9 hours ago, Laie said:

Maybe it's just too late for me to grasp it, but why do lighter rockets score less?

Because a lower score is better. The best craft would be one with the lowest number of unlocked nodes, that weighs least, and has the largest payload.

@Teutooni the first node counts so you have 3 nodes unlocked (have updated the rules to make it a bit clearer) otherwise all node 0 scores would be 0. Also procedural tanks are fine. your score is now 545.78823

@NathanKell I think you have a good point about payload, I will adapt the rules so your score is divided by your payload in tons so a 40t rocket that requires only node 1 and a payload of 2T would score 20, this should reward players who put more into orbit and greatly discourage the use of a cubic strut for a payload, hehe.your score is 464.86904, currently the leading score

@Phineas Freak the start node counts so your node score was 4, adding the payload fraction as well unfortunately makes your score 6411.36842 putting you in third place

Apologies to those who have already entered previous to the payload scoring addition, if you think you can get a better score you are most welcome to submit another entry.

OP updated, looks fairly close at the top end. Can anybody knock @NathanKell from his leading spot? We`ll have to wait and see!

 

Edited March 18, 2016 by John FX

[NathanKell]

I (or anyone) could probably get the mass down to 37t, I think. As you saw from the shot there's probably 100-150m/s extra on that bird.

[Laie]

As I find it impossible to come up with a tier-0 vessel that's not basically a clone of NathanKell's, I'm now trying for a 16t Vanguard.

Update: 1000 x -80km. Grmph.

Edited March 18, 2016 by Laie

[NathanKell]

Another interesting approach would be Early Avionics only. I believe an LV could then be done for about 20 tonnes using tier 0 engines and tanks, but with the Early 1m instead of Starting, and the X-Ray core. That would, however, have a higher score than one might expect because the X-Ray core is ~8kg vs the 60kg of the sounding rocket core.

Oh, also @John FX I suggest you clarify "required / recommended" to "recommended / suggested" since I think that is the intent. That is, the mods RP-0 should not be played without (but will not, say, _crash_ without) vs the mods that can be added but are not needed for the normal experience.

[John FX]

28 minutes ago, NathanKell said:

Another interesting approach would be Early Avionics only. I believe an LV could then be done for about 20 tonnes using tier 0 engines and tanks, but with the Early 1m instead of Starting, and the X-Ray core. That would, however, have a higher score than one might expect because the X-Ray core is ~8kg vs the 60kg of the sounding rocket core.

Oh, also @John FX I suggest you clarify "required / recommended" to "recommended / suggested" since I think that is the intent. That is, the mods RP-0 should not be played without (but will not, say, _crash_ without) vs the mods that can be added but are not needed for the normal experience.

OP updated to be clearer about the mods for the challenge. Required and recommended mods are OK but not the suggested ones

[a_schack]

Excellent timing. This is exactly where I am in my current playthrough, so I thought I might as well share what I came up with. I had two design candidates, the Phantom 1a and the Phantom 1b competing to be the one I sent to orbit, and eventually the Phantom 1b was chosen, mainly for its simplicity and lower stage count compared to the Phantom 1a.

The payload weighs in at a whopping 62kg and consists of a sounding rocket telemetry unit, a thermometer and a procedural nosecone. The whole vehicle has a mass of 32.025t, but I'm not using parachutes to recover the booster stage. First stage is an NAA-75-100 A-6 burning for 140s followed by an AJ-10-37 burning for nearly the full rated burntime (114s), followed by two unguided stages: The first is spun up using rotated seperation motors and is running on an AJ-10-27 (60s) and finally an XASR-1 (56s). What makes this craft particularly good is that 3 out of the 4 engines run at less than their rated burn time, so are a lot less susceptible to failures.

Edit: This is using just the Early Orbital Rocketry and Start nodes.

I use MechJeb Ascent Guidance to launch my rockets, but I usually have to fiddle a lot with turn end altitude and turn shape, but not with this one. It just works. 40% turn shape, 160km altitude, turn start at 100m/s and end at 0 degrees. That got me into an orbit of 186x1828km. I was intentionally carrying extra delta-v since it was pretty cheap and I wanted a safety margin. This was afterall made for my playthrough and not for the contest.  
I can get it down to 31.8t if I drop the excess delta-v, but who's counting?

Pics: 

http://imgur.com/a/r29eA

Craft files:
https://drive.google.com/file/d/0B6QwuxB14qLjTmxSMXZhakFsMHM/view?usp=sharing
https://drive.google.com/file/d/0B6QwuxB14qLjUGUyOXoxVjA1VmM/view?usp=sharing

And bonus screenshot of the Phantom 1a, which was scrapped - that was also an A-6 followed by an AJ-10-37, then by two stages of AJ-10-27s and finally 11x + 3x +1x +1x Baby Sergeants:

Edited March 22, 2016 by a_schack
Add craft files

[Laie]

2+1 Vanguard for boosters, 3+1 WAC (in XASR config) for circularization. Craft file resides next to the picture for those who are interested.

Flies easily:
1) rather steep ascent, you ought to reach 180+km with the first two stages.
2) Abort (Backspace) some 2-4 seconds before the second stage is finished. This will cut the main engine. Verniers keep running, providing control and ullage. (Only manual control, though; or at least my MJ wouldn't do it after Main Engine Cutoff).
3) point at the horizon, ignite 3rd stage when time-to-apoapsis is about 40 seconds.

That's (2x16)/0.089 -> 359 points. Though I'm certain that the design could be much refined by moving more weight to the last stage.

Possibly important: I've done this with an RP-0 install that's about a week old; RP-0 has updated at least once in the mean time.

Edit to add: the basic design is sound. There's plenty room for error; one can easily add RCS thrusters for control and ullage so the vernier thing isn't necessary (hint: 2000 nitrogen are plenty). By shifting a little weight around between the tanks, I could get it down to a 14t lifter for a 100kg "payload". Though I don't know if it should count as payload if you shove as much tankage as possible into the last stage.

Other findings: a AJ10 upper stage doesn't seem to be worthwhile, ever, if you only have the most basic tanks.
 

Edited March 19, 2016 by Laie

[John FX]

Some good entries, well done, especially to @Laie who is now in pole position.

Edited March 19, 2016 by John FX

[Laie]

Because I can't leave good enough alone...

The vanguards are pretty good engines; the next node(s) don't provide a significant advantage (certainly not comparable to jumping from A4 to Vanguard in the first place). So I tried moving the avionics to the final stage and powering it with a vanguard as well. It would almost, but not quite, work out.

Then I noticed the Heinkel cockpit. Which weighs the same as a probe core, has unlimited control (saving me 600kg of avionics on the first stage) and a 400l integrated fuel tank (15kg saved on the last stage). Ladies and gentlemen, I present you the Skinny Minnie:

(clicking the pic should give you the full-size view with readable numbers)

I can't help that it looks like an Alessi juicer. Also, yes, that's 17 WACs on the first stage. If you only have 9200m/s no matter how you roll it, a high TWR on takeoff becomes necessary. I'd also like to point out how the four boosters are actually two pairs, burning out a few seconds after each other; in the mean time one can hot-stage the center engines while pulling only a very gentle 1.2g.

It's not obvious from the screenshots, but the launch was a little too steep to begin with. I went prograde-1 immediately after tanking the picture, then gradually pitched up later in the ascent. The last vanguard stage was pulling prograde+12 for most of the time in order to push me to a 150km apoapsis. Trying to get there in one smooth prograde-only burn I'd be a few hundred m/s short for circularization; by doing a shallow launch first, then pitching up later, I obviously gained more horizontal speed overall so the pod could circularize (and then some).

So now I claim 750kg to orbit with a 40t launcher and two techs, or 107 points.

Sadly, the only way of getting my brave kerbonauts back to earth is revert to launch. Which I will now do.

[John FX]

That`s impressive. A tenfold increase in payload and getting a kerbal into orbit.

That is going to be very hard to beat.

Well done. Will update OP later today, have to tidy for the landlord visiting.

Edited March 21, 2016 by John FX

[Laie]

 

6 hours ago, John FX said:

Will update OP later today, have to tidy for the landlord visiting.

No worries; and lest I forget: thank you very much for posing this challenge. It's been fun, and on top of that I've learned a thing or two.