0.24.X - The Easier Ion-to-Orbit Challenge

[thereaverofdarkness]

This challenge is like some others, but with gentler restrictions on some of those rookie designs. You can use a reasonable number of control surfaces and a bit of RCS like you might on any other ship. There are some restrictions on how these can be mounted, but you shouldn't have any issues with them if you aren't attempting to break the physics of the game. There are some "breaks in physics" that players routinely use without always realizing it, and you can take advantage of these within the challenge guidelines. This challenge should be easy for rookie spacecraft engineers to enter and place in, while it will discourage some of the more aggressive metagaming and physics exploitation often seen here done by the expert players. Experts are still welcome to compete as long as you play by the rules. Most of you rookies probably won't even need to read much past the next paragraph. I won't instantly disqualify someone for minor rule infractions, but will point them out and place them accordingly on the leaderboard. Just make sure you read the last paragraph on posting rules before you post!

TL;DR: ^

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The Challenge:

The basic challenge is to make it to Kerbin orbit on an ion-powered craft. To count as orbit, the periapsis must be at least 69,078 meters in altitude. Of course you don't have to reach orbit to score in the challenge, but anyone who does will be categorized separately from those who do not. This challenge is prompted by the new 0.24 PB-ION thruster which had its thrust boosted to 2kN. If you are not using version 0.24.X you may still play in the challenge but you'll want to alter your ion engines to be like those in the latest version.

Acceptable Propulsion:

Some mods are accepted for certain purposes. Your ion engines must be the stock PB-ION Electric Propulsion System with 0.25t mass, 2kN thrust, 4200 Isp, 8.729 electricity per second, and 0.485 xenon per second. You may use any style of RCS/translation controls you like, burning any type of fuel you like, provided they are operated with the translation controls (default IJKLHN) and have an Isp no higher than 260 at any altitude. RCS fuel you use must burn through mass as quickly as standard RCS. No fuel of any type other than electricity (that means no RCS fuel) may be collected during the flight unless you are outside Kerbin's atmosphere and you are collecting the fuel from a ship you are docked with.

Your net dV expenditure in getting to orbit must be at minimum 75% from your ion engines. No other RCS restrictions apply.

Allowed Control Surface Placement:

You may use wings and control surfaces from any mod, provided they use the same mass, lift, deflection range, and surface area ratios as the stock wings and control surfaces or those within B9 Aerospace. If Firespitter, FAR, or KW Rocketry have any fixed wings or control surfaces then those are also valid. Rotary wings/propellers are not allowed, including those you build with stock parts. You may use any number of physics-free parts provided the craft is within part number guidelines (details below, and very relaxed) and is clearly not using any of them to generate any significant amount of thrust. No infinigliding allowed. This is defined as a craft that needs no propulsion to stay afloat and can gradually increase its speed/altitude ratio without losing mass.

You may use as much wing space as you like. Control surfaces are limited to being placed on the trailing edge of wings only, except for a single allowed pair of control winglets placed near the front of the craft attached to the fuselage. No control surface may clip any other control surface. Your lift from control surfaces may not equal more than 1/2 of your lift from static wings. No parts may be attached onto a control surface.

Ferram Aerospace Research atmospheric physics is allowed and ranks separately from stock atmospheric physics.

Part Clipping:

Minor clipping of parts (mostly accidental) is allowed as long as it looks decent--I am aware this sounds a bit sketchy. I'll be the judge on whether the clipping is legal or not, but I'm pretty lenient. As long as you don't activate part clipping in the VAB/SPH, don't use any attachment nodes twice, and don't have large amounts of parts visually clipping into other parts, you should be fine. As long as I don't suspect you of trying to cheese the challenge, I won't pick on your craft. This challenge is for the rookies, after all.

Part Count:

Entries with 1000 parts or above are disqualified. Entries with 500-999 parts must pass my inspection, and will be disqualified if I suspect gratuitous exploitation of physics. If you have a high part count craft that you think fits within the spirit of the challenge, post anyway and mention why you think I should allow it. I might give it a special section of its own.

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How to post an entry:

Include pics of your craft showing all the parts as well as the craft both on the ground and at max altitude and/or surface velocity, or in orbit if you reached it. Detail pics may be the same pics as the demonstration pics. Video of the flight is excellent if you have a recorder. Craft files are excellent for settling disputes about validity. You are strongly advised to have a dV readout, such as Kerbal Engineer, to show how much dV you spent getting up there--the less, the better. Any mods you used need to be detailed in your post. Show your part count. If you are carrying illegal engines on your ship, make sure it's clear they are off for the whole trip and only count as cargo. Any dead weight counts as cargo. Brag about it! If you suspect your entry will be disqualified, post it anyway and explain your concerns. You'll probably get an entry in the leaderboard and at minimum you'll get an explanation from me of what I like/dislike about your design.

How entries rank on the leaderboard is just my personal opinion and so entry #1 isn't necessarily superior to entry #2, etc. Next to your entry I'll list your relevant stats such as max altitude and surface velocity, dV expenditure, cargo mass, whether or not you reached orbit/periapsis for almost orbits, and a few other things you want me to put in for you for bragging rights. For best results, present your relevant statistics in a list for me. More bragging rights will tend to improve your placement on the leaderboard.

MY ENTRIES (ALL STOCK):

1.) 27,971m, 795m/s, 60 parts

LEADERBOARD

STOCK PHYSICS

1.) GoSlash27 - sun periapsis 591,400km, final velocity 3425m/s - **ORBIT ACHIEVED**

2.) GoSlash27 - 44,630m, 2035m/s, same as below with more drop tanks

3.) GoSlash27 - 35,034m, 1550m/s, 201 parts, 2 xenon canister drop tanks

4.)

5.)

FERRAM AEROSPACE PHYSICS

1.) Yakky - **ORBIT ACHIEVED**

2.)

3.)

4.)

5.)

Edited August 17, 2014 by thereaverofdarkness

[GoSlash27]

Just to be clear, is this an SSTO challenge, or are we permitted to drop dead weight?

Best,

-Slashy

[Sirine]

This might take forever to reach orbit...

Op where is your proof of this can be done.

[zarakon]

This might take forever to reach orbit...

Op where is your proof of this can be done.

http://forum.kerbalspaceprogram.com/threads/75704-Reach-for-orbit-with-an-ion-glider%21

[Sirine]

http://forum.kerbalspaceprogram.com/threads/75704-Reach-for-orbit-with-an-ion-glider%21

Your net dV expenditure in getting to orbit must be at minimum 75% from your ion engines..

Check this out.

[MarvinKitFox]

Your net dV expenditure in getting to orbit must be at minimum 75% from your ion engines. No other RCS restrictions apply.

This restriction should be rephrased, as an upper limit in m/s for non-ion propulsion.

Reason:

As currently phrased, I could sit on the runway, burn my way through 3 tanks of xenon (about 15000 dV), and then go to orbit using 5000m/s of normal propulsion.

And yes, with the new rcs engines, all rcs restriction does is enforce slightly low isp engines, so it can be used as pretty normal propulsion.

[zarakon]

Check this out.

Everything in the thread I linked is 100% ion, other than maybe some minor infiniglide

[Sirine]

Everything in the thread I linked is 100% ion, other than maybe some minor infiniglide

Yeah, but you can't denied that expert like you will need to take more than 30mins just to get that plane to orbit Kerbin.

[rtxoff]

This restriction should be rephrased, as an upper limit in m/s for non-ion propulsion.

Reason:

As currently phrased, I could sit on the runway, burn my way through 3 tanks of xenon (about 15000 dV), and then go to orbit using 5000m/s of normal propulsion.

And yes, with the new rcs engines, all rcs restriction does is enforce slightly low isp engines, so it can be used as pretty normal propulsion.

I think it is phrased correctly

Your net dV expenditure in getting to orbit must be at minimum 75% from your ion engines.

, burning that xeon on the runway would not contribute to getting into orbit like the sentence says. So perfectly fine expressed IMO.

[thereaverofdarkness]

This restriction should be rephrased, as an upper limit in m/s for non-ion propulsion.

Reason:

As currently phrased, I could sit on the runway, burn my way through 3 tanks of xenon (about 15000 dV), and then go to orbit using 5000m/s of normal propulsion.

And yes, with the new rcs engines, all rcs restriction does is enforce slightly low isp engines, so it can be used as pretty normal propulsion.

What you use for something other than getting to orbit doesn't count. Also, any speed you have left over when you leave the runway counts toward your dV to orbit expenditure.

[thereaverofdarkness]

This might take forever to reach orbit...

Op where is your proof of this can be done.

You don't have to reach orbit to score. I'll be doing my own entry soon though. Mine will be in the OP but outside the leaderboard, due to the arbitrary nature of scoring.

Just to be clear, is this an SSTO challenge, or are we permitted to drop dead weight?

Best,

-Slashy

You can drop weight, but I actually don't think it'll help you much with an ion craft, and if you do rely on staging too much it won't get you very high on the leaderboard. I myself might even drop spent ion tanks, since they seem to go empty pretty fast now, but that won't reduce the craft weight by much.

Edited August 5, 2014 by thereaverofdarkness

[thereaverofdarkness]

Here's my first attempt. There might be more. The fourth image in the album is supposed to be the first.

My entry demonstrates a legal distribution of control surfaces for anyone who is curious. You can use all the side-mounted batteries and xenon tanks you want, as long as you don't clip them or go over the part count. I am told they have no mass in flight, which is why I chose to use only in-line xenon and batteries. It seems more valid that way. My craft ran out of xenon but I am skeptical that it would have gone much higher if I had brought more.

I placed the xenon tanks at the front to bring the center of mass forward. It also has a clamp-o-tron jr. on the nose which I was intending to use for refueling if I got it into orbit. I didn't use any RCS as that would have added weight I don't need.

Results:

Max altitude: 27,971

Max speed: 795

Delta-V expenditure: NFI

Part count: 60

<iframe class="imgur-album" width="100%" height="550" frameborder="0" src="//imgur.com/a/NLwDo/embed"></iframe>

I'm not sure how to get this album to embed, so here's the link:

http://imgur.com/a/NLwDo#0

Edited August 6, 2014 by thereaverofdarkness

[GoSlash27]

My first entry:

1,550M/sec @35,034 M altitude.

It's got minimal control surfaces and 2 xenon canister drop tanks. 201 parts (mostly solar panels), exact mass unavailable, but extremely small. No RCS on this aircraft, so DV for ions is 100%. Oh, and 100% stock KFP 24 installation.

IONosfear1.craft

-Slashy

Edited August 6, 2014 by GoSlash27

[thereaverofdarkness]

Nice work!

Do you think that dropping the extra tanks off helped much?

I was pondering a multi-stage ion craft much like a multistage rocket which would drop off ion tanks, ion engines, and wing parts so that as the ion tanks were spent, the whole craft would get smaller. But it might be easier to just use side-mounted xenon.

[GoSlash27]

Nice work!

Do you think that dropping the extra tanks off helped much?

I was pondering a multi-stage ion craft much like a multistage rocket which would drop off ion tanks, ion engines, and wing parts so that as the ion tanks were spent, the whole craft would get smaller. But it might be easier to just use side-mounted xenon.

Absolutely. The xenon tanks are notoriously piggy and they comprise a large percentage of your total mass. Nearly half of a xenon tank is just tank, so it's in your best interest to drop the empties. AFA dropping wings... I haven't played with that enough to know for sure. Definitely worth dropping wings once you're above 30KM since they don't do anything up there but add weight and definitely worth keeping below 20KM, but I don't know where exactly the transition occurs. I imagine it depends on the wing loading of your craft.

Best,

-Slashy

[GoSlash27]

Entry#2: IONosfear 2.0.

Same exact craft with a couple more drop tanks.

44,630M @ 2,035M/sec.

I ran some numbers on it today, and it turns out that staging the drop tanks instead of keeping them nets me an additional 660 M/sec, but that understates the gains. Dropping the weight keeps you from running into the equillibrium problem with gliders where they can't climb and accelerate any more.

Since my second stage dumps me out at 32KM @ 1,350, I'm probably okay to dump off the wings at that stage, which is worth about 1,200 more m/sec DV. Dumping the 2 additional engines would yield a *huge* gain in DV (over 6,000), but would limit my acceleration to .5G which is pretty marginal.

-Slashy

[GoSlash27]

Success!

I have achieved stable orbit with the IONosfear platform. The combination of fixing my drop tank attachment points, adding batteries, and launching East was enough to get me into LKO with 526 units of xenon to spare. I'm going to push my apoapsis as high as it'll go before submitting my run and craft file.

-Slashy

[GoSlash27]

Stable 70KM orbit achieved.

We've still got plenty of xenon to spare. Let's see how high we can go...

Mun...check. Minmus... no problem. And oops! just escaped Kerbin. going solar retrograde. Maybe we can reach Eve? Aaand there goes Eve! C'mon Moho! Almost out of gas...

Nope. A little short of Moho. Solar periapsis of 5.914x10^6 meters, final velocity 3,425 M/sec.

IONosfear1.craft

[Laie]

Do you think that dropping the extra tanks off helped much?

Absolutely. The xenon tanks are notoriously piggy [...] Nearly half of a xenon tank is just tank, so it's in your best interest to drop the empties.

Side note: Ion-powered SSTOs are kinda pointless from a financial standpoint. The xenon costs 3000 florins; the tank, 200.

AFA dropping wings... I haven't played with that enough to know for sure. Definitely worth dropping wings once you're above 30KM since they don't do anything up there but add weight and definitely worth keeping below 20KM, but I don't know where exactly the transition occurs. I imagine it depends on the wing loading of your craft.

Suitable (radial) decouplers are as heavy as half a wing (or half an empty xenon tank, for that matter). Even the tiny stack decouplers weigh about three to one. It might be worthwhile if you drop a lot of stuff in one go.

[ihtoit]

aren't any of the decouplers massless? :\

[Yakky]

I made orbit using a lightweight single ion drive SSTO. Fully stock except FAR, no cheats or other funny business, just a singe ion motor with 4 large xenon tanks. Still had half a tank at orbit. See this post: http://forum.kerbalspaceprogram.com/threads/85728-Ion-glider-collier-trophy%21?p=1343570&viewfull=1#post1343570

Edited August 12, 2014 by Yakky

[GoSlash27]

aren't any of the decouplers massless? :\

Unfortunately, no

But if you use the TR-2V, it will drop with the expended parts.

Best,

-Slashy

[thereaverofdarkness]

I thought the radial xenon tanks were massless. Also sorry I was away from this challenge for a while. I forgot about it.

Edited August 17, 2014 by thereaverofdarkness

[GoSlash27]

I thought the radial xenon tanks were massless. Also sorry I was away from this challenge for a while. I forgot about it.

Not to the best of my knowledge. If they are, I've been going about this all wrong.

Welcome back,

-Slashy

[goduranus]

Wait a minute, this is old, but the kerbodyne decoupler is massless!

Edited September 23, 2014 by goduranus