Open Mângo’s tier 2 entries

[J3 Mângo]

I gotta admit, this was quite fun and quaint. So here’s my attempt at the grand tour:

I apologise for the long running time and secondly there is a cut in the video on a transfer window to Earth. I had to reload sfs as the game froze due to the manoeuvre node being buggy.

 

[J3 Mângo]

Rocket blueprint:
Rocket Link

 

[Astro826]

Due to the time it takes, any tour mission attempt is quite impressive; nice dedication for the 50 minute mission (I totally didn't skim through the recording). However, because of the use of disallowed ion engines, it cannot be rated well by the criteria of this tour challenge.

 

[J3 Mângo]

Due to the time it takes, any tour mission attempt is quite impressive; nice dedication for the 50 minute mission (I totally didn't skim through the recording). However, because of the use of disallowed ion engines, it cannot be rated well by the criteria of this tour challenge.

For starters, I didn’t properly read the rules , secondly I thought Ion engines would do the trick instead of assembling an oversized craft comparable to an ISV. And finally the recording was more of 70 minutes long as I messed around with the craft in orbit after as when it got back to Earth it still had 21% fuel left .

 

[Mooncrasher]

Congratulations on your first attempt, shame about the ions indeed but I have confidence in you.

Remember you can do some posting as you go, like "here's the rocket I'll use for the second try" etc.
Maybe bring some impactors and/or a few tiny probes to do some science as you fly past.

 

[J3 Mângo]

Congratulations on your first attempt, shame about the ions indeed but I have confidence in you.

Remember you can do some posting as you go, like "here's the rocket I'll use for the second try" etc.
Maybe bring some impactors and/or a few tiny probes to do some science as you fly past.

Heck I’d think I’m playing good ol’ KSP with science! Sounds good so I’ll come up with some ideas. As I’m releasing a planet pack today as well.

 

[Darthan]

I have a question about this:
From the rules for the grand tour:

Nothing must be missing from the combined craft when you enter or depart the SOI of a planet except discarded stages..

Maybe bring some impactors and/or a few tiny probes to do some science as you fly past.

These two seem to contradict each other. An impactor or probe (orbiter?) is not a discarded stage so cannot be missing from the combined craft? It would be impossible to get an impactor back. Getting an orbiter back may be near impossible.

I'm a bit confused about the need for this rule.

I've done a little research into this. A test grand tour (with just a probe as the payload) in Normal was possible using an under 150t launcher (I attempted to take screen shots of this but the steam screenshot system - which I was trying out - decided to lose most of them). With two build screens it might be possible to carry about 100t as the payload, which might be enough for 12 small impactors (every body except the Sun and Earth) but the 'Nothing nust be missing ...' precludes using impactors? A mix of orbiters and impactors may be also possible - but not if the orbiters have to be returned to the flyby craft.

 

[Mooncrasher]

The intention of that rule is to prevent you splitting up your mothership and doing flybys of different bodies with sub-components rather than the whole thing, and re-integrating at some later stage, and also stop you from doing tanker depots along the way. Both of these make it less of a "grand" tour.
It's not intended to stop you from leaving behind probes or contrivances of any kind at a body for "science", that never meet the mothership again.
I'll get that rule reworded to reflect that.

 

[J3 Mângo]

How do you lot recommend I redo this mission?

 

[Mooncrasher]

Step by step, first make a craft and a plan, then check here if that craft and plan would get the score you want.

 

[J3 Mângo]

Step by step, first make a craft and a plan, then check here if that craft and plan would get the score you want.

Plan: get into LEO then burn towards the moon, pass that around and burn to the captured asteroid. Then burn towards mars about 630m/s. And get into close orbit. Burn and encounter its 2 moons then burn towards Jupiter. Orbit Jupiter and encounter its 4 moons. Go in order of moons: Ganymede, Europa, Io and Callisto.
Then burn directly to Mercury and pass that by. Then burn towards Venus and pass the planet. Then likewise to Venus burn to Earth. Pass it by once and come back around to land.

 

[J3 Mângo]

I just profoundly flew through the solar system and remarkably no ion engines! This is my new design and it’s able to visit every celestial body in the grand tour!

 

[J3 Mângo]

Here’s my second attempt:

 

[J3 Mângo]

Rocket blueprint:
Rocket Link

 

[J3 Mângo]

I hate to be a pain in the ass but can someone please look at this?

 

[Mooncrasher]

I think this gets a score of three, for doing the bare minimum.
There's a lot you can do with oberth effect, aerobraking, gravity assists and thoughtful piloting in this mission to make it efficient, but you didn't really do any of that.
The things that stand out negatively were your launch trajectory, doing things in an unoptimal order, doing burns unnecessarily far from a heavy body and lack of aerobraking.

For the launch trajectory, you made your gravity turn rather late and high. There's so much fuel you could save by turning like your life depends on it, and not worrying about reaching 100°C. Typically the angle-o-meter Stef was generous enough to give is a bit conservative for many rockets, so don't be afraid to push it.



For the second thing, for example you wasted fuel on doing burns to reach mars after the moon and asteroid. You could have, for example, made mars your first destination, and timed your transfer so that the moon would be in the way whilst you went to Mars. So that you could accomplish the moon flyby for nearly free.
You could have left the asteroid for later in this scenario, maybe swinging past it at the end before you re-entered.

For the third and fourth things, you always want to take advantage of what nature gives you for free. The closer to the surface of a body you do your burn, the more dV you get from the burn, free boost from gravity.
And always take advantage of aerobraking if possible. Why did you enter orbit around the earth at the end rather than just diving into its atmosphere?

As an extremely rough guideline (I didn't check to be sure), if you could do this without the stage that has the two kolibris, it would be notably more efficient.

 

[J3 Mângo]

So if I do some aerobraking, utilise the orbeth effect more effectively and visit the Moon first and the asteroid last instead of second do you think I’ll get the 4th point?

 

[Mooncrasher]

Add in some gravity assists too, maybe.
Earth - Venus - Jupiter, then work your way down from there, visiting mars then lowering your periapsis to see mercury (keeping apoapsis higher than earth), and then back to earth.

 

[J3 Mângo]

I’ve decided to stick with my original plan, I experimented with aerobraking and the difference it makes is negligible. So I thought chaining a few gravity assists when flying from Jupiter to Mercury to circularise my orbit enough to get a slow enough encounter with Earth to land again.

 

[Mooncrasher]

By the way, you may wish to read this, those musings from a judge may give you some inspiration.
Open - Enhanced Grand Tour

 

[J3 Mângo]

Well I play on IOS, so Hard mode is the best option for me. But how about I attach some small atmospheric probes to the touring rocket and launch them into the atmospheres of Earth, Venus, Mars and Jupiter to do some “Science”? Would that get any 4th point?

 

[Mooncrasher]

That would help a lot, I think. You could do the probes, and at the same time try to make your vehicle as small as possible to demonstrate how little dV you can do the whole tour with.
I think currently your vehicle has nearly 10,000 m/s of dV? That's probably excessively overmuch, as said before.

Atmospheric, impactors, landers, return landers that catch up before you leave the SOI, there's lots of possibilities to pick from for "science".

 

[J3 Mângo]

That would help a lot, I think. You could do the probes, and at the same time try to make your vehicle as small as possible to demonstrate how little dV you can do the whole tour with.
I think currently your vehicle has nearly 10,000 m/s of dV? That's probably excessively overmuch, as said before.

Atmospheric, impactors, landers, return landers that catch up before you leave the SOI, there's lots of possibilities to pick from for "science".

I’ll send 4 atmo probes and an impactor to Mercury. If I do all this will I get 4 points?

 

[Mooncrasher]

Yes if the execution is good and efficient. Post the rocket before you go for the full mission, as a further check.

 

[J3 Mângo]

Small probes to the side are the atmo ones and the one pointing upwards is an impactor.