SSTO Large-ish Tour - Flight of the Decade Thrush

[McQuacker]

Starting my first mission report: a log of my attempt at a Large-ish Tour using my "Decade Thrush" craft - a fully stock SSTO. The craft is showcased in the SSTO thread:

Note: not an actual Grand Tour. This craft is definitely not Eve-capable and I have strong doubts about Tylo as well. The rest should be possible.

Leg One: Kerbin - Minmus

Ready for take-off!

We have lift-off! Thanks to the little dip at the end of the runway, or we'd have run straight into the sea.

Landing gear retracted. The front gear is placed inside a cargo bay to protect it from overheating. The little fairing at the nose doesn't contain anything, it's just the nose part with the highest temperature tolerance (2700 K).

Almost at 8km. There we pitch down to about 15 degrees and start building speed.

WHOOSHH!!

Living on the edge; if the nose doesn't get within half a degree of exploding, you're not going fast enough. Personal record speed before the Rapiers switch to closed-cycle is 1,450 m/s.

Apoapsis reached 75 km. All engines switched off and cruise until we do the circularization burn.

We need another 275 m/s to circularize.

Done! Not a perfect orbit (76 by 88 km) but close enough. And with about 1,450 m/s delta-V left in the tanks - more than enough to reach Minmus and refuel using the on-board ISRU equipment.

Planning a burn to get a Minmus encounter.

Meanwhile, Bob performs an EVA to collect the data gathered in Kerbin's upper atmosphere. The ship contains a complete set of science equipment.

The Minmus encounter after a small correction burn. We need a polar orbit for the ore scanners.

Close enough. With some small corrections, we can start looking for resources.

It would be nice if the Narrow Band Scanner's GUI included a color bar - apparently, increasing concentration go from green to yellow to red. Minmus doesn't have much in terms of resources, but with 4 large drills and a large converter, the Thrush should have no trouble refueling.

Found a suitable spot along the equator. The ship lands vertically on the landing legs attached to the tail fins, then flips to horizontal using the RCS thrusters. On the bottom of the cockpit there are four Vernors to prevent it from falling down too hard.

Landed!

All four drills functional. We're on a spot with about 5.5% ore concentration.

Done refueling after 15 days. Not too bad at all!

The next leg will take us to the Mun. There we'll do another refuel and then it's on to Duna. Hooray!

Edited August 25, 2016 by McQuacker
No can do!

[NotAgain]

Nice use of the fairing as a heat-shield. And, holy moly, that's fairly large.

[McQuacker]

Leg Two: Minmus - Mun

Small cheat. I got to Duna but got stuck there with a ship that wouldn't roll on its wheels anymore. Discovered they were broken and figured fixing them could work but equipping the ship with bigger wheels would be better. So I restarted the mission with a ship with bigger wheels. Apart from that, everything is the same.

The next leg takes us to the Mun. The Decade Thrush lands there, refuels and goes back to orbit.

First, taking off from Minmus. The low gravity makes this very easy, since the four Vernors under the cockpit are powerful enough to pitch the nose up even when the fuel tanks are full. Fire up all the engines (including the Rapiers) for a few seconds to get a clean lift-off, then burn the Poodles for a few seconds to raise the apoapsis. Cruise there and circularize. And of course we left a flag to prove we were there!

Now we fly for the Mun. We could wait for a better transfer window, but since the ship has enough delta-V to make the trip about ten times over, why bother? So we go for a horribly inefficient but quick route:

Encountered the Mun. Circularizing takes a lot of delta-V (without a burn we'd be swept out of Kerbin's SOI entirely) but that's no problem.

Kill orbital velocity and start the descend. Freefall until altitude reaches about 4km and fire up all engines to kill vertical velocity. Use the Poodles to control the last part of the descent and land vertically.

Almost there!

Touchdown! The RCS thrusters and reaction wheels together are not powerful enough to tip the ship over, so we had to retract the bottom (or front, depending on your frame of reference) landing legs.

Success!!

Start the drills and the converter and wait for the fuel tanks to refill. This takes a few days.

That's it for now. The next leg will take another stop on Minmus to refuel and spend a few months on the surface waiting for a good transfer window to Duna - around day 231, according to this lovely tool: http://alexmoon.github.io/ksp/
In my last attempt I found out that landing the thing on Duna like an airplane is impossible. Vertical descent is very tricky but it can be done - after a few attempts I did manage it but the wheels broke, as a mentioned earlier. Hopefully the next attempt will go more smoothly and allow me to get back into orbit. I figure the ship should have ample delta-V to get to Ike for another refuel and then onto the Jool system, but taking off from Duna will be very tricky. Anyway, you'll see soon enough!

[McQuacker]

Leg Three: Mun - Minmus - Duna

We're about to leave Kerbin's SOI for a long time and go explore the vastness of interplanetary space! However, best to do this with as much fuel as possible, so we make a short refueling stop on Minmus.

Taking of from the Mun is quite easy, though slightly trickier than from Minmus. A short boost by the Rapiers helps us gain altitude quickly enough to avoid crashing into a hillside. After that, the Poodles cn get us to orbit easily enough.

I won't bore you with the Mun - Minmus transfer - it's much the same as the last post, only in reverse. So, we go straight to the Minmus landing. I stopped bothering with the whole polar orbit thing for ore scanning - the difference in ore concentration barely makes any difference in fuel production and it's a lot of hassle changing orbits all the time. Luckily, I already did a scan for Minmus and left a flag last time, so we can aim for that.

So, we landed on Minmus and refueled the ship. Departed again and waited for a proper transfer window to Duna (around Year 1 Day 231). Waited till Minmus was in a good position in it's orbit around Kerbin and took off!

There are still some issues with the game engine changing it's orbital calculations slightly when moving from one SOI to another - when I left Kerbin´s SOI my Duna apoapsis had changed to about 150 km, requiring me to do another small correction burn. Not much in terms of fuel, but if you forget and warp straight to Duna, you miss the planet.
So, here I just reached Duna´s SOI. Small correction burn to get a proper equatorial orbit.

A full aerocapture is not possible, since the ship doesn't have any heat shields. Still, even some light aerobraking can drastically decrease the amount of fuel needed for the insertion burn.

And afterward:

So now for the tricky part: landing. I tried doing it horizontally (spaceplane-style), but found that it's not doable - at least not with this ship. Wings are way too small, making the speed required to remain airborne way too high. So, rocket-style it is.

The Poodles can handle the whole thing, since the tanks are almost empty, making the ship light enough for this. Just follow the ballistic curve, decreasing speed all the way. When near the ground I switch on the RCS too to keep stability. The last three hundred meters or so are the trickiest - decreasing vertical speed to fast will make the ship topple over (even the RCS can't keep her upright then), but too much speed will crash the ship. It took a few attempts, but I did make it in the end. Here's a shot halfway through the descent - 1,500 m altitude and about 15 m/s vertical speed.

Did it! And luckily for me, I landed on a lovely little eastward slope, ideal for taking off again.

Refueling took about 18 Kerbin days, not too bad at all.

That's it for now. The next leg will take us up to Ike and then it's on to Dres!

[McQuacker]

Leg Four: Duna - Ika

Since I'm busy anyway, might as well post the next leg. It's a short one anyway, but interesting (I think) because it involves the first take-off from another planet. In a previous attempt I got stuck on Duna. I thought it was because the landing gears were too small for the ship, but it turned out they just got damaged during the landing and I could just have Bill repair them. Ah well, bigger gears don't damage as easily so it's still an improvement.
Anyway. Since Duna's atmosphere doesn't have any oxygen the Rapier's won't go into airbreathing mode here, meaning a vertical take-off would be more efficient. However, the four Vernors underneath the cockpit are not powerful enough to get the ship vertical when the tanks are full. So, we have to do it horizontally. Luckily we landed on a very nice eastward slope, making things a lot easier.

First we build a little speed with the Poodles, just to make the aerodynamic controls a bit easier.

The next part involved a short burn with the Rapiers to increase airspeed and make sure the ship doesn't literally drop from the sky. Unfortunately in all the excitement I forgot to take a screenshot. So, here's a few seconds later. The Rapiers have already been switched off again (you can still see them glow) because from now on the Poodles can handle it on their own.

Keep burning until the apoapsis gets out of the atmosphere (50+ km for Duna) and then cruise until you are there.

I did another small burn to get the apoapsis above 60km for easier time-warping later on. Not necessary, but there's fuel to spare, so why not?

That's the hard part done. Getting to Ike is very easy, since it's got a relatively large SOI and is very close to Duna. The change in SOI happens about two thirds of the way there.

From here on it's much like the Mun. Insertion burn, circularize, kill the horizontal speed and drop down to the surface. Around 3-4 km start burning again to kill the vertical velocity and make a controlled descent.

And there we are! Landed on Ike with over 800 m/s of delta-V left in the tanks.

The next leg will take us to Dres. In an earlier post I said it would be Jool. However, I did that, but it took too much delta-V, leaving me in a highly elliptical orbit around Jool with barely 800 m/s left in the tanks - not nearly enough to land anywhere. So I figured I'd go to Dres first and refuel there. This worked like a dream - currently, the Decade Thrush is standing on the surface of Laythe, waiting for me to take her up again. But that's for later posts!

[McQuacker]

Leg Five: Ike - Dres

As it turns out, Dres is tricky to get to. It's got a gravitational pull about as strong as Ike's, very weak for a planet. This means its SOI is very small and therefor getting an encounter requires a *very* precisely tuned maneuver.

The first part is getting back into orbit around Ike. This is much the same as for the Mun, so no screenshots. Here we are orbiting Ike, with a planned maneuver giving us a Dres encounter. The apoapsis is way too high, but we'll correct that later when it's less sensitive - I could set all the engine thrust limiters to 10%, but waiting a while means I can plan the maneuver node more easily. As can be seen we had to wait quite some time for a good transfer window - over three years, to be precise. Luckily for us, stock Kerbals are immortal and don't need food, oxygen or other such trivialities.

So here's a correction node planned to get the apoapsis down.

Here we are in a circular orbit around Dres. As can be seen the tanks are quite empty now, since the delta-V required to get from Ike orbit to Dres is quite large.

Landing is the same routine as with any other body without an atmosphere - kill the orbital velocity and drop down.

Done!

That's it for now. The next leg of the journey will take us to Laythe!

[septemberWaves]

I really like this spaceplane design.

[McQuacker]

Leg Six: Dres - Laythe

Previously I explained that I decided to make a stop on Dres to refuel in the way from Duna to the Jool system. Although this does indeed mean that we arrive at Jool with fuller tanks, it also means that because of the inclination of Dres' orbit, we arrive at a very steep angle. Trying to change the inclination of an orbit around Jool by brute force requires gargantuan amounts of fuel. Instead we'll do a flyby of Tylo on the way, which will not only change the inclination of our orbit to nearly coincide with the ecliptic, but will also bring us in orbit around Jool without needing an insertion burn. Hooray for physics!

Taking off from Dres is much the same as for most moons, since its gravity is so weak. Notice the time - we had to wait over 8 years for a suitable transfer window. Luckily Kerbflix has reception throught the Kerbol system these days, so the time passed by easily.

Whereas getting an encounter with Dres requires extremely precise aiming, Jool is almost impossible to miss.

We've entered Jool's SOI. Here we see the planned Tylo flyby. Neat trick, eh?

Here we see Tylo in the passing.

Planning the Laythe encounter. Luckily Laythe is quite forgiving for aerobraking, so we can afford to arrive at some speed. In my first attempt I messed up and arrived on the wrong side of the planet, orbiting it counter-clockwise. I did manage to get into atmospheric flight but over the middle of the ocean with almost no fuel left.

Planning the capture. No aerobraking, just a regular insertion burn. We have more than enough fuel anyway, and an aerobrake is still tricky to get right.

Starting the descent. Starting out from a 60km orbit, I place my periapsis at about 40km and land roughly at that spot. The first few minutes are really boring - you need to stay in the upper atmosphere and watch speed drop very slowly, until you can decrease altitude safely without burning up.

Aiming for the Greenland-shaped island. I'm pretty confident it really is Greenland, by the way - I work as a climatologist IRL and have seen that map too often to miss it.

Starting the more exciting part of the descent. I could have waited in the high atmosphere a while longer, but I got bored.

Almost through the gates of fire, so to speak. Airspeed drops very fast in this last phase.

Almost there. I did a quicksave at this point and had to go back there about 20 times before I got the landing right - at one time I thought I nailed it, but then I opened the cargo bays and all the ISRU and science equipment came tumbling out.

Touchdown! I used the RCS to try and keep her on the ground, sometimes she'd bounce over a little bump and explode.

Did it! All refueled and ready for the next leg.

I already attempted going to Vall, but ran out of fuel halfway through the descent. I'll need to do some work on my Laythe ascent profile first, since I got into orbit with about 1,500 m/s left in the tanks on that attempt, which should be a lot more, methinks. Anyway, you'll see soon enough

[McQuacker]

All right, it seems I'm a bit stuck. It's hell to take off from Laythe, since 9/10 times the ship explodes on a small terrain bump before it becomes airborne. Optimizing my Laythe ascent profile is therefor a rather tedious task, but still needed - I've always arrived at Vall with about 80 m/s too little delta-V left in the tanks, crashing the ship on the surface. Also, the transfer from Laythe to Vall is tricky because Vall's orbit almost intersects with Laythe's SOI, meaning you need to time the ejection burn very carefully to avoid overshooting and ending up with a way too high velocity on arrival.

I still think it can be done, but it will take some time.

[PGTART]

nice blog, got here from ssto thread