Jump to content

Detailed log of mission to Duna and back (with pictures)


Puck Man

Recommended Posts

Hello my fellow Kerbonauts and welcome to my mission log. In this log I will be updating you about my ongoing mission to Duna.

For starters I will give you my resume. I am a recurring player which means I tend to stop playing for large periods of time and come back later, usually when a new version is out. I know my way around the game but everytime I come back I always find re-learning spacecraft design being exceptionally hard, especially with new parts being added and all. I have been to Duna, Ike, Laythe, Moho and of course the Kerbin system, successfully landed on all but never returned except from the Kerbin system missions.

But now, for the first time, I have decided that I will no longer abandon Kerbals about the solar system and instead try to bring them back. My obvious choice for my first mission of tha kind was Duna; easy to get to, easy to land on, easy to return from. I have sent many missions there, about 6 landers on Duna, 3 on Ike, two rovers on each and numerous probes. I believe I know enough of the place to be able to design a suitable spacecraft. Whether my current design will make it back I am yet unsure but I am confident it will make it there with fuel to spare, perhaps not enough to get back but enough to have mobility within the system. So, on to my spacecraft!

After many hours on the drawing board and many failures, I started to get the feeling of it once again. The spacecraft is composed of three pieces, the transfer module which will make the trip to and fro and two landers. Powered by two nuclear engines, it will carry a lander for Duna and a lander for Ike, both manned. The landers will be capable (in theory) of landing to their respective bodies and then return to meet with the transfer module to transfer crew, after which they will be either left in orbit for possible future use or de-orbited. The spacecraft will be constructed in orbit in 5 planned flights, not counting the refueling shuttles. Thus far 3 have been completed.

The first flight got the main core of the transfer module in orbit. I had initially planned to put the whole thing up there at once but it proved too heavy for that (or my rocket building skills are lacking) so it has been broken into three separate pieces: The core, the habitation module and the engines. The remaining two flights are the landers.

The second flight got the engines attached to the station

XTrhnus.jpg there you see the engines whilst in orbit waiting to rendevouz with the main core.

The habitation module will go in between the engines and the core but I sent them first to grant the module some mobility in order to save payload on the other parts. That way I need only get the parts near the module and then I dock it on to them (as I did with the engines which I just left there and danced around them perilously until I finally docked) instead of outfitting them with maneuvering gear that can barely fit on them and is also dead weight as far as anything other than docking is concerned.

The third flight got the Duna lander up there. Adequatly fitted to get back up after landing and designed to be as light as possible, it was quite the challenge to dock (though not as much as the engines were which had zero mobility once they were separated from their transfer module and were even listed as debris.) I could not fit 8 RCS thrusters on it so I had to make do with four, two on each side and not one on each quarter as I would have liked but the engines were blocking much of the surface of the lander. That means that I could only have two axes of motion at any time. The constant back and forward and the variable left/right or up/down. To change between the two I had to rotate 90 degrees.

37Vfhbh.jpg the Duna lander being flown to orbit.

But with a slow and cautious approach and a lot of spinning I managed to finally dock.

DTgogtN.png the lander docking.

The two remaining flights will be the addition of the habitation module and the Ike lander. The order will be decided by which I finish designing first. After the construction is complete, shuttles will be sent to pick up excess astronauts I was too bored to remove prior to take off and as many refueling shuttles are needed to fully refuel the spacecraft and landers. After that I will be good to go although I am considering launching a fuel tanker on the same launch window, just in case the transfer module does not have enough fuel to make it back so that I can refuel whilst there and not have to make them wait until another one arrives. I will leave it to the more experienced ones to examine my design and tell me if that will be necessary.

sVvPThz.jpg better view of the spacecraft.

I will update the log as soon as construction is finished.

Edited by Puck Man
Link to comment
Share on other sites

They are wings, those long thin ones. I did have some spin issues but nothing a few control surfaces on those wings or winglets cannot fix. But even those are optional. The spinning did not set me off course or balance and it settled down as I got higher.

The reason I chose such a design was because there was not enough available surface on the lander to attach stuff onto.

Link to comment
Share on other sites

The I.T.M. (Interplanetary Transfer Module) has been fully assembled and is almost good to go! There is only one thing missing (and a lot of fuel), the Ike Lander which will be flown up to dock with the I.T.M. with the 5th and last contruction flight.

The 4th flight brought the Habitation module to the I.T.M. ,it will be where the 3 Kerbonauts piloting the landers will go when they are ready to return home. The flight was a success although it nearly turned into a disaster halfway in. I had used a simillar launcher to that I used for the Duna lander which, as you can see in the pictures, is composed by 3 tanks with engines connected to the center module with swept wings. In order to keep the module free of separator remnants I connect the wings to a small fuel tank which is placed on top of the center module. The fuel tank's contents are also necessary as the fuel the transfer module carries are not enough for the entire mission.

Some moments after I had stopped adjusting my orbit I thought it would be easier to perform the remaining maneuvers and burns if I ditched the tank so I separated with it and then got to tweaking a maneuver noed. Once I had the desired outcome planned out it was time for the burn, so I fired up the engine and shortly after crashed with the tank I had ditched and what a crash that was. There was a lot of distance between us as the separator packs quite a punch. Luckily that same separator got in the way of the collision and took the hit for me and getting destoryed in the process. Nothing was damaged on the Habitation module and the mission could proceed as planned.

I finally met up with the I.T.M. and slowly approached to dock. I would dock on the side port where the Ike lander is gonna go so that I could undock the engines first. I preferred that method than just undocking the engines and then docking the Habitation module because it involved only one thing hovering dangerously close to the I.T.M. . Also, the Habitation module was running out of both fuel and RCS and I needed to restock. I restocked half the RCS and the entire fuel tank because I do not know the ratio in which the liquid fuel and oxidizer need to be in the tank so I just filled it all thinking that I'd just put it back when I was done. I undocked with the engines and moved the I.T.M. a few meters away, then I undocked the Habitation module and moved it to the center port. After I was done I separated the transfer module (not the ITM but the one that brought the Hab. module) from the Hab. module and made my way towards the side port. After a few awkward bumps I realised it did not have a docking port, something that I had not noticed until now. So with a heavy heart I burned prograde and switched to the I.T.M. because I still had the matter of the engines which had drifted 100 meters away during the delay my bumping had caused. The transfer module is still in orbit I think but its suborbital trajectory will soon bring it back down, filled with precious fuel I stupidly transferred to it and didn't even use, I did the whole thing with RCS. At least docking with the engines was easier than last time.

So, even with a nearly catastrophical collision and a bunch of fuel wasted for no apparent reason, both things caused by my stupidity, the mission was a success. I have already developed the Ike lander and I will soon have its transfer stage ready as well. After the final construction flight I will only have to refuel and remove excess Kerbonauts, something I will attempt to do on a single flight even though I have never actually created a successful fuel tanker and trust me I have tried a lot. After that I will be good to go! I will keep you posted.

Here you can see an album with pictures from the mission. Pictures have descriptions.

Javascript is disabled. View full album
Link to comment
Share on other sites

There are two models to go by when building rockets. The So-much-thrust-on-it-payload-is-of-no-matter and the So-little-payload-that-the-thrust-is-of-no-matter. It is by the second one I designed the Ike lander. An Mk1 Lander Can sitting on top of an FL-T200 tank and surrounded by three FL-T100 tanks. Along with only the completely necessary, such as a battery, solar panels , a docking port and landing legs, the lander is powered by only 4 tiny Rockomax 48-7S engines. With a total thrust of just 80kN and carrying only 225L of fuel I did not expect the lander to even be able to take off. I was actually planning to take it to the Mun for testing since its gravity is only slightly stronger than Ike's. Still, I wanted to at least burn and go nowhere on Kerbin so that I could see what I had to work with and how many changes I should make. To my surprise, the lander did not only lift off but it was also very efficient. The three side tanks are not really needed for their fuel as much as for the surface they provide to the spacecraft, allowing me to place the extra 3 engines which are needed to slow down from orbit and land. Also, placing the landing legs there will lessen the chances of the lander toppling over when touching down. I assume that the 3 radially mounted engines will be sufficient to get me in a sub-orbital trajectory from Ike orbit and see me to the ground intact. After that whatever fuel is left will be used for liftoff and once the tanks are completely drained they will be decoupled. From that point on the lander will rely on a single Rockomax 48-7S, an engine with a thrust of 20kN mind you, to get in Ike orbit and rendevouz with the I.T.M. . To my surprise, that engine too was more than enough to lift the main lander body. After getting such results on Kerbin testing I was confident that the design would be more than adequate for Ike. Below you can see the lander during Kerbin testing.

C6ETTLo.jpg

After the lander design was complete I started constructing a launcher, sticking to the same philosophy as for the lander. I ended up with a basic 2 stage rocket. The first stage's purpose was to get me to orbital altitude, the closer to the I.T.M.'s the better.It carried 4320L of fuel in a Jumbo-64 and an X200-32 tank on top of a mainsail to boost it all up. The second stage would get me to orbital speed and make the adjustments needed to rendevouz with the I.T.M. . It was an X200-32 tank with a Poodle engine. I didn't really expect it to work and I was just gonna use it to gauge what kind of payload I was dealing with. But I was in for yet another surprise, that launcher actually got me to the I.T.M.

Everything may seem like it is going just perfect for me at this point but the actual flight was not as impecable as you may think. I launched believing I would not make it and I just wanted to see how far it would go. Surely enough, the stage that was supposed to get me in orbital altitude barely got me above the atmosphere. I fired the Poodle which did not do much for me, I was losing speed and the trajectory expanded very slowly. I almost terminated the flight and went back to the drawing board but for whatever reason I stayed and tried to see if the Poodle would surprise me. And it did! I was at apoapsis now, just a little bit higher than the I.T.M. which was approaching hauling ass. I generally try to launch when it is closing in so that by the time I am up there I am close enough to it to not have to orbit a gazillion times to rendevouz . I burned prograde, trying to reach its speed before it overtook me. The Poodle was struggling and hadn't really accomplished anything until now but blessed be the Oberth effect, as I passed the apoapsis and started picking up speed, the Poodle was suddenly adequate to get my speed up just where I needed it. The I.T.M. overtook me but only for a little, not long after it did I had matched its speed and now I was moving close to it again.

My initial worries that the launcher would not be up to the task where not all that unjustified. The first stage had failed to do what it was supposed to and the second stage only barely managed to save itself from plummeting back down to Kerbin. I had little to no fuel left, if I had delayed or hastened my launch by just a little it is quite possible that I wouldn't have enough fuel for the orbital maneuvering. No worries though, now that I am so close to the I.T.M. I only need RCS ,right? Well, sorta. You see even though the transfer stage was equipped with 8 brand new, state of the art RCS thrusters, I had forgotten to put any actual RCS on it. You see as I mentioned before it wasn't really supposed to be used for the actual mission so I was not as diligent during the construction (even though it is not rare for me to send half finished stuff up, most common instances being forgetting to put solar panels on stuff). Still, I wasn't gonna give up now. My fuel was on the two digits now, as I approached the station I though of trying to carefully utilise it to dock, I have docked without RCS before and the transfer stage I use is pretty much the same for everything. Buuuuuuuuut I failed. 10somethingL of fuel now, I just carefully burned retrograde and came to a stop, or something close to that, near the I.T.M. .For once more, I docked the now quite large and wobbly I.T.M. to the smaller piece instead of the opposite, remind me to put RCS on stuff. Nevertheless, with all its setbacks and shortcomings, the mission was a success.

Now I just need to refuel the I.T.M. and its detachable components, extract some excess crew and leave a total of only 4 Kerbals on board, and I will be good to go. From what I gather, the commnly accepted definition of a good fuel tanker is something that can get a full orange tank ,at least, to the desired target. Needless to say I have miserably failed with much much smaller quantities. And as if that wasn't enough, I am thinking of combining the tanker with the crew shuttle. I have bitten off more than I can chew but hey isn't that what Kerbals do anyways?

The mission album has been updated with screenshots of this flight. You will find it on my previous entry.

Link to comment
Share on other sites

Construction is done, refueling was relatively uneventful if we don't count dancing around the engines I slightly touched and sent rolling for 40 minutes until I had to refuel again and then remembered that time warp stops rotation. So what is left? But there can only be one thing, the mission!

The crew waited patiently for the proper allignment. I believe I got it right but I just couldn't get a good encounter, also the moon kept getting in the way of a very good trajectory. I decided to get out of the Kerbin system on a trajectory without an encounter, I would tweak it later without the Mun blocking my way all the time. I fired the engines and got to it. Unfortunately SAS could not handle the assymetric weight and I had to keep it from spinning manually. Mech Jeb might have been able to handle it but I do not bother with mods because it tires me to re-install or remove them after every update. After 4-5 orbits I was finally heading out, my confidence high since the engines seemed to be in a good balance of efficiency and performance.

My Duna periapsis is high and no matter which way I burn I cannot seem to be able to lower it. I decided to wait until I was closer to try. The visualisation of my future trajectory was very misleading and I ended up on a very bad trajectory. I had to make a burn of at least 1000m/s, the third one I was doing in this flight. Remember I had to keep it steady manually and those burns lasted about 10 mins. But at last I was there, I was finally there. Duna and Ike were now visible from my location. I had put too much confidence in the ship's efficiency and I was too hasty instead of waiting for the right window. Most tanks were practically empty, I was running on the 720L tank and I had a total of 2880L for the trip to and fro. I aerobraked successfully and I put myself in an eccentric orbit. That way both landers would need to burn very little to go to their respective targets. First went the Duna lander, burning retrograde from apoapsis. As if having spent more than half the I.T.M.'s fuel was not enough, another thing was wrong as well, the lander did not have solar panels. At least I had remembered to put batteries, just a Z-100 nothing special but along with the lander can's capacity I had more than enough. Landing was much easier than expected and the lander proved to be very efficient. I got the two Kerbals out for pictures and flag planting and went quickly back inside while the charge was still on safe levels. I got up to 10k m before I had to ditch the three radial tanks.

Since I did not want to risk waiting on the surface until the I.T.M. was in a proper position for rendevouz, the two spacecraft were pretty far apart. So instead of waiting until the lander caught up I decided to launch the Ike lander.

If I had used two Duna landers I wouldn't have problems with the center of mass or the mission but I thought that the Duna lander was overkill for Ike and the less payload the better. Luckily the Ike lander was very efficient as well and it has a very good thrust to weight ratio. I undocked it from the I.T.M. at periapsis and extended my apoapsis to Ike's altitude. I would have aimed instead of just waiting for an encounter but I was too conservative with my fuel. As I orbited around Duna waiting for an encounter with Ike, the Duna lander had caught up with the I.T.M. . I docked and transferred crew and whatever fuel was left in the lander's 360L tank before undocking with it. It will continue to orbit Duna until it dies, unless the charge remains in which case I could use it as a lander again. A future mission would only have to repack its chutes and refuel it and it could go back down again. It could probably come back too but unless I managed to land it upright I very much doubt it will be going up again after a second landing.

By now the Ike lander had an encounter. I landed on the day side and planted a flag that stated that I had come at that spot. Future explorers might wanna have tissues with them if they are planning to go there. I was quite high before I had to ditch the radial tanks, the lander was stupidly efficient. I dropped back down to Duna and aerobraked for a few orbits although I believe I could have just burned the speed off and still have enough fuel to dock. Eventually I met up with the I.T.M., transferred crew and fuel and left it in orbit for the space archaeologists of the future to find. It does have solar panels but I doubt it can be of any use. No chutes for landing on Duna, no legs for landing on Ike, no RCS to become a tug for a future space station. I guess it could be an escape pod but I don't know if it can get back to the Kerbin system.

So here we are, mission accomplished. It was done hurriedly and sloppy but it has been technically accomplished. Everything but one objective that is, the getting back part. With a not quite full 720L tank I wonder if I can really make it back to Kerbin. I think I have enough fuel but my trip here proved that I could quite possibly spend 2 (or more) times the fuel needed and that I do not think I have. I need a solution for this problem and I suspect it is called Ike.

Mission album has been updated.

WVB1qbS.jpg

Link to comment
Share on other sites

692L of fuel left to get back home is where we left off last time as you may remember. As you may also remember the forums were down for a while so even though I would love to tell you about the return trip with every detail, I have mostly forgotten about it. Fear not though, there will still be accompanying photographic documentation to aid with the storytelling. With it, and whatever vague description of the events I am about to give, you may piece together the final leg of my trip.

So the crew is in Duna orbit, low on fuel, probably not enough to get back. But luckily enough, a textbook of Astrophysics for dummies was lying around the cabin and the crew learned about the wonders of gravity assists, and so they set course for Ike. According to the Interactive illustrated interplanetary guide and calculator for KSP, I needed to be orbiting the other way around, something I did not have the fuel for, and have a planetary phase angle of -75 degrees. Getting into Ike orbit eliminated the need to change my orbital direction but I still needed to wait for the right window, or did I? As you may remember from my coming trip, I kinda forced an encounter instead of waiting for the right window (which resulted in spending 3/4 of my fuel just to get there).

I may have kinda done the same here. Luckily, Ike is generous and gave me an encounter trajectory with only a burn of about 400-600ÃŽâ€v (can't remember exactly how much it was). Keep in mind that I did not re-load a quicksave during this trip, I did it all in one go. The only times in this trip that I reloaded a save was in the beggining, in Kerbin orbit ,when I was trying to set up a good trajectory and find the right window, and when I was coming on to Duna for aerobraking at which I failed many times. Aside from those moments, the rest were done on the first try.

Coming on to Kerbin, I realised my inclination was completely off but I did not want to risk wasting my precious fuel for a plane change. I had set a periapsis of about 40km, if I remember correctly, which I soon realised was not enough and I was gonna get flung back out. So right at the periapsis, with the Oberth effect working against me, I burned to close my orbit around Kerbin. I ended up in an oblong orbit with a very, very, high apoapsis, just enough to get into orbit. Any higher and I would escape Kerbin's SOI.

I made an additional 2-3 passes at 40km to lower my apoapsis and then burned a bit to raise my periapsis. I was now in a mostly circular orbit, at about 200km above Kerbin with only 139L of fuel left!

Had I been smarter, I would have put parachutes on the Hab module and just plunge right back into Kerbin. The I.T.M. , which is a good spacecraft but needs a lot of refining, would be destroyed and I'd make another, better, one. But I did not think of doing so and I had to send up the F.G.K.C. (Fuel Goes Kerbals Come) spacecraft to pick them up. The FGKC delivers fuel and can bring back 4 astronauts. Seeing as how I did not need to preserve the fuel, the flight up to the I.T.M. was fairly easy. I had to wait until the KSC was under the I.T.M.'s orbit because it was not equitorial and I didn't launch at the best of times but I managed to get alligned with some minor corrections. To my utmost surprise, I had forgotten to put solar panels on the FGCK, shocking. Luckily I managed to put it in a good orbit for rendevouz but the charge would run out before I actually met up I.T.M. so the final maneuvering would neeed to be done with the I.T.M. .

The FGKC was in sight, I dithced the engines which had caused me so much trouble, never to see them again, and docked to transfer crew. Here's the deal though, the FGKC was meant to be used as following: FGKC docks with target,manual separation of fuelt tank with Hab module, fuel tank is Sepratron'd out of orbit, then Hab module is Sepratron'd out of orbit. Instead of manually separating the two I just pressed space which separated them and activated their Sepratrons at the same time so I accidentally pushed my landing spot to the sea instead of land as it was before. But even so the landing went smoothly, a bit of plasma here and there, some paper bags may have been filled, but the two radial parachutes held and the capsule was seen intact to the ocean.

It had been done, they had returned. For the first time in (my) Kerbal Space Program, an interplanetary mission had returned. The crew was retrieved and plans for the next mission have already started. A space station above Dres perhaps? It would make sense since it is right in the middle of the system, good for refueling stops or launches to the outer planets. Or a mission to the Jool system, Eve, Moho? Who knows? All we know is that now, we are unstoppable.

Mission album has been updated.

Javascript is disabled. View full album
Edited by Puck Man
Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...