Launch Efficiency Exercise [Updated for 0.21.1]

[SRV Ron]

Now that I have looked at this, the posted pic in the first post, in 0.21, you could ditch some weight by eliminating the batteries, nose cone, and stack decoupler. (Jeb becomes expendable.) Easy to low orbit with good flight skills with some fuel left for return.

Congratulations on those that achieved stable orbit with the unnecessary weight of the four battery packs.

[tavert]

The additional parts were to make it the same mass as the design when the original challenge was created, in 0.20, which had an ASAS unit for manual flying purposes. ASAS units are much heavier now, so had to change to some other combination of parts that added up to 0.1 tons.

[SRV Ron]

May be time to redo this challenge in the future. But, add that Jeb would need to be return safely after being placed into stable orbit. Should be doable with the small amount of fuel left at such a low orbit.

[Bobnova]

First try here, entirely manual. I overshot the apoapsis oops.

The craft:

[Tarmenius]

It's good to see some activity here again.

May be time to redo this challenge in the future.

That is definitely the plan. I wanted to create a follow-up to this a couple weeks ago, but there was no mid-term lull this time around, so I haven't had the time to give this the attention it deserves. Finals are this coming week, though and then I'll have two weeks free, during which time there will be a follow-up with a low-TWR craft and possibly a re-make of this one now that I'm more familiar with the new mechanics. Although it will not include a requirement re-entry (as the focus here is on the efficiency of the ascent itself), perhaps a bonus category could be made for those who kept enough fuel in reserve to bring the pilot home.

First try here, entirely manual. I overshot the apoapsis oops.

Congrats on completing the challenge! I'll bet that if you get your Ap low enough, you can make it into the Double-Digit Club. Now let's see if I can add your entry to the Scoreboard... Anyone know how to force the forum to make new paragraphs? Edited September 9, 2013 by Tarmenius

[Cosmitz]

Tried this multiple times, would need around 30-40 more units of fuel each time to get in an orbit. I end up with bloated apoapsis more often than not.

Later edit: Ok, got closer, but really, still need a few squirts of fuel to get my usable orbit, otherwise it ends up as a very long space-cruise.

Edited September 10, 2013 by Cosmitz

[Tarmenius]

The fuel margin is pretty tight, that's for sure. A careful combination of ascent path and throttle management is essential for success. Sounds like you're making progress though, so keep it up and you'll get there. And feel free to ask any questions if you find yourself hitting a wall.

[Respawn]

doh. 0.00 @ 75499 x 76750

abit slow on killing engins at the end there haha.. tight margin for sure

i'll do some more attempts.

Edit:

yeah.. after a couple more attempts I managed to get an orbit of: 77556 x 75045

With some fuel left. 1.43 units of liquid fuel.

Better than 0.00

Here's a quick video: (2x speed playback)

Edited September 10, 2013 by Respawn

[Tarmenius]

Respawn, a score of 0.00 still counts as a success in my book. If you reach the minimum orbit with no fuel left again, take some screenshots and I'll add you to the scoreboard.

[Respawn]

btw: Its manual but with kerbal engineer info panel.

[Epthelyn]

Here's my two attempts, one without Mechjeb and one with, both following roughly the same ascent path: Begin turn at 10km, horizontal at 40km or above.

Vanilla - I messed up on the altitude a bit by pressing the wrong key, but got into orbit with 0.34 units of fuel left.

MechJeb Autopilot - All settings and dV stats are shown on screen. It would've been nice if MJ had actually achieved an orbit above 74x74 when I told it to do 74km, but instead it gave me 74.2x73.8 and required a little manual adjustment 6.23 units of fuel remaining

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This challenge really shows that if you know what an efficient ascent path is, there really is no excuse not to reach orbit

[Tarmenius]

Respawn: Congrats on another successful mission! Your entry has been added to the Scoreboard. Thanks for the video as well, it's always good to see how other players achieve their orbits.

Epthelyn: Congrats to you as well! I added your best attempt to the Scoreboard, but let me know if you'd rather have your vanilla attempt displayed.