damerell

Ascent profile challenge

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damerell    305

This isn't a craft design challenge, but a piloting challenge. This rocket is an all stock craft; the aim is to fly it to Kerbin orbit with as much fuel unused as possible.

Some rules:

  • You may use any mod for information or control purposes - eg MechJeb, KER, VOID, kOS.
  • I expect you will be doing this in sandbox mode and so will have access to a 5-star pilot with full SAS control.
  • You may adjust the rocket's thrust limiters and staging; you may disable (but not remove) reaction wheels and control surfaces. You may not otherwise redesign the rocket. Clarification; that includes tilting the rocket before takeoff.
  • Exception: if a control mod (eg kOS) requires a part to be added, you may add that part. It must not provide any other benefit (eg fuel, propulsion, a reaction wheel).
  • You may use FAR or stock aero as you please; say if you used FAR. Other than that, you may not use mods which change the game's physics, the behaviour of parts, etc.
  • The final orbit must have a periapsis of 180km or more and an apoapsis of 200km or less. Other orbital parameters are unspecified.
  • Show your working. Someone else reading your entry should be able to try and reproduce your ascent profile. Whether that means providing a kOS script, inputs to MechJeb, or a youtube video of you flying it up, the idea is that the best piloting techniques will be able to be followed by other players.

My first post in this thread will be an example entry.

Stock Aero FAR
Reactordrone - manual ascent - 170 LF  
damerell - "Gravity Turn" mod - 164 LF  
killakrust - MechJeb ascent guidance - 162 LF  
Foxster - MechJeb ascent guidance - 154 LF space-is-hard - kOS script - 145.7 LF
Boris-Barboris - 139 LF
Part manual with assistance from own Atmosphere Autopilot plugin
Yakky - manual - 145 LF
sdj64 - manual with Better Time Warp - 136 LF TheGreatFez - kOS script - 142.96 LF
space-is-hard - kOS script - 134.65 LF
Special mention for most gratuitously METAL entry
damerell - MechJeb ascent guidance - 138 LF
swjr-swis - manual ascent - 103 LF  
Edited by damerell
new technique

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HoloYolo    1263

You might want to post a download link. Also, by your rules. I can use the ALT+F12 method and get into space with all the fuel remaining.

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damerell    305

This is an example entry. It shows that entries don't have to be lengthy depending on the technique used.
I use FAR. I set up MechJeb's ascent guidance as in this screenshot. I did not fiddle with the thrust limit on the SRBs (because I already fiddled with it with my challenge organiser hat on). Then I pressed the spacebar.
ascent-1-takeoff-small.png
MechJeb flew me to orbit and as seen here I have 138 units of LiquidFuel left, 2.08km/s dV.
ascent-2-orbit-small.png
I hope you can all do better than MechJeb. :-)

 

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sdj64    567
35 minutes ago, HoloYolo said:

Also, by your rules. I can use the ALT+F12 method and get into space with all the fuel remaining.

This is not constructive at all, besides, everyone says for challenge posters to read the challenge submission guide but anything about contestants?  Nope.  See "no one likes a wiseguy".

 

Ascent profile challenges have been done before but I don't recall any for 1.0.5.  Final orbit height is a bit unconventional since most will go to 100km or lower.  Curious to see what the best ascent profile is!

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damerell    305
56 minutes ago, HoloYolo said:

You might want to post a download link. Also, by your rules. I can use the ALT+F12 method and get into space with all the fuel remaining.

Do you mean other than the craft link in the OP?

Yes, you certainly can. Will anyone regard that as a legitimate entry? Obviously not. Is it a waste of time to try and list every possible way one might cheat a craft into orbit? Yes.

If you've got a legitimate question about something sensible the rules don't cover, go ahead.

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swjr-swis    1454

A quick entry:

 

This is on a pure stock 1.0.5, no mods at all, with the given craft unedited straight to the launch pad. Don't consider this a serious attempt at a title, it's just to show it is absolutely possible without any mods, and with a practically untrained pilot.

The start of the launch is missing because being completely stock and missing a probe core or CH-J3, keeping to the ascent profile needed constant manual input up to where I could hit prograde, and I could not screenshot at the same time. Maybe attempting it a few more times I can figure out a split moment where to hit F1.

 

The ascent profile is a basic one though, nothing special:

1 - SAS on, for what it's worth with a 1-star pilot

2 - Full throttle

3 - Launch straight up

4 - When surface speed reaches 100m/s, start tipping the ship forward, keeping the navball pointer a few degrees under the 'lower' edge of the prograde circle marker. In this fully manual setup, that requires constant 'tapping'.

5 - When boosters are empty stage immediately, keep burning full throttle and keep adjusting your heading as before.

6 - Watch the navball speed indicator: right when it switches from 'surface' to 'orbit' speed, click on the follow prograde, and switch to map view.

7 - Hover cursor over the apoapsis marker while continuing to burn full throttle. When apoapsis reaches just over 180km, cut throttle completely.

8 - Breath, the difficult part is over. Use this time to set up a maneuver node at apoapsis for a 180x180km orbit.

9 - Manually point the rocket.

10 - Don't trust the burn time indicator: you won't have enough fuel left in this stage for the full burn, so start the burn early, full throttle.

11 - When fuel runs out in the lower stage, stage and keep burning full throttle

12 - When you get close to 20-ish m/s left to burn, you might want to cut throttle and finish at low thrust. You should still be well within the burn 'window', and have plenty of fuel to fine tune to your heart's content.

 

* The above is kind of a worst case. A much shallower profile is possible, where boosters and the lower stage are fully used in the atmosphere, along with a small bit of the top stage, but my computer's USB bus is having a problem causing stuck keys at the worst moments. I got one one attempt to coasting with 171 units left, the circularization maneuver node to need 266 m/s, which I think would've left me at more than 138 units... and then a stuck key ruined it. I'm too disgusted to try again tonight. 

Would it be completely out of spirit of the challenge to allow a CH-J3, to somewhat level the playing field with MechJeb users? Perhaps in place of the parachute (since the challenge only calls for putting it in orbit, not to return). Anyone using a low-star pilot is at the disadvantage of having to follow the node manually.

Have fun y'all. Even if I didn't manage with this attempt, my money is on a manual launch doing better than the default MechJeb profile.

Edited by swjr-swis
wanted to try again, thwarted by hardware

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damerell    305
9 hours ago, swjr-swis said:

1 - SAS on, for what it's worth with a 1-star pilot

Aha, my bad. My intention was that you would do it in sandbox mode with a 5-star, but of course, you can't tell what's in my head. Updating the OP, and thanks.

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damerell    305

Given a 5-star pilot, is there any reason to want a probe core? I'd edit the post above but for some reason the forum won't let me.

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Boris-Barboris    394

swjr-swis's ascent is asctually 103 LF, not 231.

Stock semi-manual (used AA for handling, less wobbly than SAS) 139 LF, http://imgur.com/a/jeuU5, early turn to ~60 degrees altitude, shallow trajectory. Rule of thumb - use prograde hold, control by thrust, change only initial pitchover maneuver, don't be afraid of heating.

Edited by Boris-Barboris

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damerell    305
1 hour ago, Boris-Barboris said:

swjr-swis's ascent is asctually 103 LF, not 231.

Stock semi-manual (used AA for handling, less wobbly than SAS) 139 LF, http://imgur.com/a/jeuU5, early turn to ~60 degrees altitude, shallow trajectory. Rule of thumb - use prograde hold, control by thrust, change only initial pitchover maneuver, don't be afraid of heating.

Oh, good catch, that'll teach me to look a bit more closely. I've put you in. I infer you don't use FAR. Score a brownie point for using your own flight aids.
I should do a non-FAR "just let MechJeb have a bash" to establish a baseline.
Re earlier, 180-200km is quite a high orbit, but I figured it would at least make the answers not quite the same as last time. :-)

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killakrust    37

OK, here is my submission. Stock + MJ

SRB's set to 100%, Mechjeb turn shape 20%, altitude turn starts immediately.

141 LF left over.

Edited by killakrust

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Foxster    2428

A quick go from me with 154 LF left...

Stock + MJ.

All throttle limits at 100%.

Don't start the Swivel until the SRBs are finished (i.e. move the Swivel to stage 3).

MJ profile like this:

hNlQHl4.jpg

BxnRFGI.jpg

Edited by Foxster

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damerell    305
7 hours ago, killakrust said:

OK, here is my submission. Stock + MJ. 141 LF left over.

And surprisingly sanguine about the near-explosion of the chute. Also, I'm curious to know why you rotated the rocket before takeoff? On a two-booster model I prefer to eject them sideways.

2 hours ago, Foxster said:

A quick go from me with 154 LF left... Stock + MJ.

Strong performance - and it does seem to be the battle of the MechJeb profiles, doesn't it?

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killakrust    37
7 hours ago, damerell said:

And surprisingly sanguine about the near-explosion of the chute. Also, I'm curious to know why you rotated the rocket before takeoff? On a two-booster model I prefer to eject them sideways.

Lol, yeah. I kept pushing the curve lower to get that last bit of dv. I stopped when I saw the chute get so close to exploding.

afaik the craft loaded into the vab in that orientation. I certainly didn't rotate it deliberately.

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killakrust    37
14 hours ago, Foxster said:

A quick go from me with 154 LF left...

Stock + MJ.

All throttle limits at 100%.

Don't start the Swivel until the SRBs are finished (i.e. move the Swivel to stage 3).

MJ profile like this:

 

BxnRFGI.jpg

Your AP is too low. It needs to be 200km. You will need another 2 LFO to correct that. <-- Ignore this, I am a spaz.

Edited by killakrust

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killakrust    37

A second shot for me...

Mechjeb turn shape 35%, craft pitched over a bit on the pad, SRB burns first like Foxter's,

160 LF remaning. :wink:

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swjr-swis    1454
3 hours ago, killakrust said:

Your AP is too low. It needs to be 200km. You will need another 2 LFO to correct that.

His apoapsis is fine, the rules state it should be '200km or less'.

4 hours ago, killakrust said:

afaik the craft loaded into the vab in that orientation. I certainly didn't rotate it deliberately.

Yes, it loads oriented to the east. I did not rotate it either.

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damerell    305

Hm. The craft rotation must be stored _somewhere_, but apparently not in the craft file. How curious. (If I load it, it turns up north-south). Well, you can rotate it if you want to.
Will update the OP when I get a minute. As swjr-swis says, the constraint is only that 180km <=Pe <= Ap <= 200km. (Of course, Pe <= Ap is true by definition).

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killakrust    37
1 hour ago, swjr-swis said:

His apoapsis is fine, the rules state it should be '200km or less'.

Yes, it loads oriented to the east. I did not rotate it either.

Dur, I read it as minimum Pe and Ap. I need to lern to read better I guess. Darn, I could do this with 162 LF left over in that case.

1 hour ago, damerell said:

Hm. The craft rotation must be stored _somewhere_, but apparently not in the craft file. How curious. (If I load it, it turns up north-south). Well, you can rotate it if you want to.
Will update the OP when I get a minute. As swjr-swis says, the constraint is only that 180km <=Pe <= Ap <= 200km. (Of course, Pe <= Ap is true by definition).

I figured out what happened with the rotation. In order to add MechJeb to the craft I detached the fuel tank (+ lower stages) and added the MJ box to the bottom of the battery. When the tank was reattached to the battery it rotated around 90 degrees.

Edit:

Yup, can be done with the same settings as my previous attempt. Now with 162 LF remaining:

zLDhfrX.png

Edit Edit:

FYI, this does not qualify for the challenge (I assume), but if you remove the winglets you will save 10 LF due to less weight and drag:

xjf1L7H.png

 

Edited by killakrust
Some reason... because.

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swjr-swis    1454
1 hour ago, damerell said:

The craft rotation must be stored _somewhere_, but apparently not in the craft file.

The craft rotation is stored in the parts, I think most importantly in the root part (in this case, mk1pod).

Instead of the default:

    rot = 0,0,0,1
    attRot = 0,0,0,1


this craft is stored as:

    rot = 0,0.7071068,0,0.7071068
    attRot = 0,0.7071068,0,0.7071068

That's what makes the whole craft spawn at the launchpad heading east instead of north.

 

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hvacengi    137

Do you have an intended "limit" to submissions?  I'm going to modify my kOS scripts to work with this design (it's a bit out of my own normal parameters) but figured it would be good to know a realistic "deadline" (also, my ADHD does better with deadlines...).

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swjr-swis    1454
38 minutes ago, hvacengi said:

my ADHD does better with deadlines...

60 seconds to deadline... 59... 58...

Sorry, you kinda made that real easy. :D

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hvacengi    137
4 minutes ago, swjr-swis said:

60 seconds to deadline... 59... 58...

Sorry, you kinda made that real easy. :D

I've got 14 tests done already.  While none of them win, I can at least get one turned in within a 5 minute window apparently :wink:

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swjr-swis    1454

Seriously though, and just a suggestion since I'm not the OP:

I think this is a good challenge for new players of KSP. As such, leaving it available at least until 1.1 comes out (and then maybe renew) would allow participation of more than just the established players.

(apologies for the double post... the 'merge double posts' is apparently not consistent either, sigh)

Edited by swjr-swis
because forum quirk

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