Sepratron Height Challenge

[Godot]

Manned: 57427 m

Rocket:

End Flight:

Album:

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

Edited June 2, 2013 by Godot

[robertordf]

Are you people fireing them as the former stage depletes? Or are you waiting to be slowed down to avoid drag losses?

I fired each stage when about 20-30m/s less than terminal velocity so after the burn I got to about +10-20m/s

Optimal is always V = Vterminal, but its difficult with SEPRATRONs

Also, it is great to be as fast as could in the first stage, a TWR 10 helps a lot. Mine is ~4 due to stress

[ShachonianX]

I think I have reached the limit of how high my design can go. Here is my last height reached.

[robertordf]

I am starting to designing a theoric max dV craft

using 1.6 TWR and probe, gives me a theoric of 7200dV with 57stages / 1500parts ... will try that!

[cakepie]

Here is my 50-stage, 1301-sepratron monstrosity (unmanned).

It lags my computer so bad (less than 1fps while loading, and for the first several stages!) that manual control is practically impossible until a large portion of the stages are spent -- I had no choice but to incur a cost of 180kg additional mass for ASAS and fins to automatically counter wobbling (seems to be caused by drag and stack separator jerk). Luckily this is sufficient to keep the correct end pointed towards space with very little manual intervention.

We have liftoff. That's 120 sepratrons firing at once!

Final stage fires; by this point we've almost reached the outer edge of the atmosphere:

Detail of final stage coasting along after fuel is spent.

Thanks to 100x warp, an hour of mission time passes in under a minute. Apokerb at 3,330,622m

The eventual inevitable fiery re-entry leading to destructive splashdown at almost 100m/s

Stages are:

(29 small diameter) - 6x2, 3x3, 6x4, 4x6, 3x8, 2x10, 1x12, 2x14, 2x16

(12 medium diameter) - 3x20, 2x24, 2x32, 2x36, 1x40, 2x48

(9 large diameter) - 2x56, 64, 72, 80, 88, 96, 104, 120

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An earlier test before the last 9 stages were added. This has 565 sepratrons in 41 stages.

(notice that the ASAS+fins assembly is lower down -- stage 33 compared to stage 15 above -- less computer lag and rocket wobble means we can discard the extra weight sooner and rely on manual control)

This reached 1,001,884m.

Edited April 17, 2018 by cakepie
freshen image links

[skykooler]

Here is my 50-stage' date=' 1301-sepratron monstrosity (unmanned).

[/quote']

With that much delta-v, you should be able to reach a higher apoapsis by achieving orbit first - that way your final stages aren't fighting gravity.

[cakepie]

With that much delta-v, you should be able to reach a higher apoapsis by achieving orbit first - that way your final stages aren't fighting gravity.

Not sure if able to do a precise gravity turn while computer is lagging that badly. Might require mechjeb, but I feel that'd be cheating. Will give it a shot later today.

[metaphor]

Got to orbit with 37 stages and 43 tons of separatrons and decouplers. Also reached 862 km altitude with the same ship going straight up. It oscillates like an accordion every time it stages.

[Cranium]

Ha! This sounds like a challenge I can sink my teeth into. I'm definitely going to try this.

[cakepie]

Too lazy to do too much re-engineering, I swapped the Octo2 core on my unmanned 50-stage 1301-sepratron monstrosity for the mk1 lander can + parachute for a manned attempt. The good news is, the manned capsule provides enough torque for control/stability, so we can remove the fins from my earlier design.

Jebediah loves it.

Is there something going on in my taskbar notification area, Jeb?

Apokerb = 148,499 (if only I'd managed to be a teensy bit more efficient...)

This would not work if re-entry was actually hot and not just pretty effects.

Looks like we're coming down not too far away from the KSC...

Landing & result

Edited April 17, 2018 by cakepie
freshen image links

[numerobis]

You would be way more efficient if you did a standard gravity turn.

You can get slightly more efficient by making the first stage have TWR about 4 or 5 and subsequent ones around 2 -- that way you speed up to terminal velocity as fast as possible, but you don't exceed it because the first stage runs out.

[Warboy]

http://imgur.com/a/6y8v2

Manned 21,020m

[lajoswinkler]

I had no idea all this was already done, and thought my achievement was noteworthy.

The oscillations upon firing the stages are awesome.

Edited September 17, 2013 by lajoswinkler