To Moho; Jeb leads another intrepid crew to the innermost planet

[DMagic]

For my next mission the administrators at KSC have decided to explore that often neglected and sun-baked inner planet, Moho.

Part 1; Probes, and the base begins

Part 2; Moho Orbital 1

Part 3; Moho surface, and getting the tugs home

Part 4; Helios

Part 5; Pyrois

Part 6; So much fuel

Part 7; Full power

Part 8; Coming together on the surface

Part 9; We can't stop now Jeb, not when we're so close

Part 10; Home at last

Moho Orbital Station | Helios Solar Station | Moho Ground Base

Mods Used:

Plugins:

Mechjeb

ISA Mapsat

Kethane

Quantum Struts

Subassembly Loader

Crew Manifest

Actions on the Fly

Maneuver Node Improvement

Parts:

KW Rocketry

KSPX

Kosmos

THSS

Large Structural Components

Icarus Project

I'll keep this initial post short and outline the basics of my plan.

- I am to establish a manned outpost on one of Moho's polar regions, complete with a research station, living space, and several exploration rovers.

- A series of probes will be launched to map Moho's surface, explore possible landing sites, and gather data for the descent and on conditions at the surface.

- Two space stations will be created to service this outpost. One will be in a low, polar orbit above Moho. It will act as a rendezvous point and refueling station, and it will house two small landers for ferrying crew and supplies to the surface and back. More details about the second station will be forthcoming.

- A series of mostly reusable tugs will be used to ferry station and base components from my Minmus orbital station to Moho, where they will be assembled in orbit or on the surface. Another vehicle will be designed to ferry crew from LKO to Moho orbit and back.

- To facilitate the launching of so many components, and to preserve my sanity, I'll also be building a series of standard launch vehicles. These will be designed to carry payloads from 1 to 50 tons into LKO.

I started by designing all of the launch vehicles. Not all of them will be used for this mission, but they should be nice to have in the future. This first series, from left to right, shows my 1, 2, 5, 10, and 15 ton launchers. There are two versions of the 10 ton vehicle, for 1.25 and 2.5 meter payloads. All of these are capable of getting their respective payloads into LKO with around 50 - 200 m/s of delta-v to spare. And all of them are designed for use with fairings, without those an additional 10-20% can be added to the mass of the payload.

This next series is my 20, 30, 40, and 50 ton launchers. There are two versions of the 30 ton launcher, for 2.5 and 3.75 meter payloads. I tried to reuse components for each vehicle. The 5 to 20 ton launchers all use essentially the same booster rockets, just more of them. And the 40 and 50 ton launchers are basically the same, I just added a 3rd pair of boosters.

I'll end this initial post with the launch of the probe pack using my 30 ton vehicle. The pack carries a small orbiting Sat Map probe on top, four identical probe landers on the sides to scout possible landing sites, and a small probe rover on the bottom that will be used to survey the final base site.

I'll update soon with the probe mission to Moho and its initial survey, and I'll get into the first stages of the orbital station launch and construction.

Edited August 9, 2016 by DMagic
Fix links

[DMagic]

Picking up from where we left off, the Moho probe pack is all set for its transfer burn. When the launch window arrives the probe's engines ignite, taking it on a course out of Kerbin's orbit and into the sun's. After a mid-course inclination change and correction burn the probe is on track for an intercept with Moho.

Arriving at a low periapsis over Moho. The orbital capture burn wasn't too bad actually, around 2800 or so m/s. Add in the 1700 m/s for the transfer burn, and another 750 m/s for the correction and inclination change and the total delta-v was about 5300 m/s, not too shabby.

After establishing a stable orbit around Moho at an inclination around 85^o the Sat Map probe was released. The probe moved into a higher orbit and began mapping the surface. It became immediately obvious that the terrain around the two polar regions differs greatly. The northern polar region is covered in mountainous terrain, while the area around the south pole is nearly flat and at a low elevation.

While the surface was being scanned the probe pack began its automated lander sequence. The first lander was dropped off for a descent to the southern polar region. Coming down to the surface it's obvious how flat this region is.

We can see from the ground that this region is suitable for a base and would make for an ideal landing site; it is a little barren though.

As the second probe is released and descends to the northern polar region we can see that the region is decidedly more rugged. There is an interesting looking crater not too far in the distance, though.

The terrain around the landing site is obviously not well suited to landing a base, it is an interesting site though, and the elevation is relatively high, around 5000 meters above the lowest point on the planet.

The orbiting probe pack then enters hibernation mode, awaiting the arrival of the first crew. From orbit, they will control the next two landers and the rover, using them to identify the final landing site.

Meanwhile, back at KSC the first station components are being launched. First up are the interplanetary tugs. This one is called Hermes, it is designed to carry two payloads, one docked to the front and the other behind it. It was launched on an older version of my 40 ton lifter.

Next up is Talaria, the winged sandles of Hermes. This was also launched on the old 40 ton lifter. It is designed to carry two identical payloads docked to the front of it, while the port on the back is used to dock to stations.

I didn't want to leave the front end of Talaria's payloads unattached, so I came up with a cap that could dock to both payloads and hold them steady. I couldn't figure out a way to do this in one craft though (I've come up with a few methods that might work since then though). So I launched this as a separate payload on my 2 ton lifter, then docked in orbit. With both ports attached Talaria is now ready to rendezvous with the other components at Minmus Orbital station.

And now for the launch of my first base component, the docking ring and central node. The ring has one of each size docking clamp to accomodate any craft. Jebadiah 'Jeb' Kerman, mission commander, is at the controls, lifted into orbit on my 20 ton launcher.

This is the fuel tank segment, launched on that same, old 40 ton lifter.

The tugs and initial base components made it to Minmus orbit and docked at the refueling station. Some still-classified components are docked on the other side of the station, limiting what can be shown at this point. The Hermes tug is in its final configuration, while Talaria awaits the other base components.

We'll continue soon with the final base component launches, the transfer to Moho, and orbital construction.

[Specialist290]

Nicely done!

Hope your experience with Moho proves to be more productive than mine thus far.

[jocax188723]

This is beautiful!

Please please keep going.

[DMagic]

Carrying on, we have the launch of the remaining Moho station components. Two solar panel truss sections were launched on my 10 ton lifter. And the two habitation sections were launched on the 30 ton lifter with Bill and Shepbro Kerman at the controls.

After four closely spaced launches (Kerbals excel at clearing off debris and preparing for another launch) all the components are set on a course for Minmus.

While those were on the way, the main station section departed from Minmus Orbital and moved into a 60km holding orbit over Minmus.

Some careful docking was required to get everything onto the Talaria tug. One of the solar truss sections arrived first and was docked to the large clamp adapter left behind by the Hermes tug.

The hab sections were then maneuvered into place at the front of the tug. Those radial docking ports look like they might attach, but they don't, they are meant for the landers, which will be coming along later.

Once everything is in place Bill makes use of the quantum whatever field to stabilize all of the components for transit. With the tug completed they leave Minmus Orbital and move to join the Hermes tug at a 60km orbit.

Now this is where the fun part begins. Normally the ideal window for a transit is when Moho leads Kerbin by about 107^o in its orbit, and the burn is conducted retrograde to Kerbin's orbit around the sun.

Being at Minmus complicates matters though; it takes about two days after burning at Minmus to fall back to around 100km above Kerbin. Kerbin moves around the sun about 3.4^o/day, while Moho moves about 14.1^o/day, meaning that Moho advances about 10.7^o/day with respect to Kerbin's position. Therefore, the burn at Minmus has to occur when Moho is only about 85^o ahead of Kerbin. And this has to take place while Minmus is at the right position, about 1/3 of its orbit seems suitable for this.

To further complicate matters you have the inclination change. Correcting for this can take over 700 m/s of delta-v if you wait until you are in orbit around the sun to do it. Being at Minmus allows for a nearly free inclination change though. If you wait until Kerbin is near an ascending or descending node with respect to Moho, then a small normal or anti-normal burn near Minmus can correct for most of the change.

Of course, waiting for all of these factors to line up would take forever, so I just waited until I was at a node and didn't really worry about the position of Moho. With a change at Minmus I was able to decrease my inclination relative to Moho to about 1.5^o instead of 7^o. Once in orbit around the sun only about 200 m/s was required for the rest of the change.

Here are both tugs burning near Kerbin after returning from Minmus. I got nervous during all of this time playing with maneuver nodes, so I sent up an additional fuel tank for the Talaria tug.

Because this burn didn't really get me on course for an encounter with Moho I just treated it more like an orbital rendezvous rather than an interplanetary transfer. I partially matched Moho's orbit, then waited for the right time to set up an encounter. The final burn near Moho was about 500 m/s for one tug and 750 m/s for the other tug.

The delta-v counts shown hear started recording when I left Minmus Orbital. Talaria made it with about 4800 m/s, not too bad, but it came in almost bone dry on fuel. Hermes had plenty of fuel since it was carrying the extra tank, but it took just over 5400 m/s to get there.

Once in orbit the first matter was to dock the fuel tank to the central node. I'm trying out a new detachable docking component method here. The large docking port used for transit is attached to the fuel tank with decoupler. Once this is blown separatrons fire, carrying away the docking port, RCS thrusters and their tank. This kicked back the fuel tank a little more than I expected, but it worked pretty well, and now I don't have to keep all those extraneous RCS thrusters on the final station.

With the central station node complete Hermes was docked to the large port on the docking node.

This next part was fun. I had to maneuver all four station components into place while keeping everything from floating away. In retrospect, it would have been easier to just dock Talaria to the station first using the regular sized port on the back, but I didn't think about that at the time.

The first solar truss was docked pretty easily. The second had some issues with my docking system, but all of the important parts survived intact.

Next the habitation modules were moved into place. The cupola modules provide a lot of torque which made this much easier than the solar trusses.

With all of the components in place Shepbro Kerman, never one to shy away from a dangerous duty, performed an EVA to secure the station with quantum struts. He returns to the station here, silhouetted against fiery Kerbol.

Now here is the completed station. All of the docking thrusters have been blasted away, the tugs are docked, Talaria is hiding in the back, and the station is secured. Everything is pretty stable, even when moving around there's not much flexing or bending.

I'm quite pleased with this station. I did some launch pad and VAB testing of the fully assembled station, but there's nothing like seeing it in orbit after actually putting everything together.

The crew is ready for the next phase, to identify the landing site and to await components of the second station. Those tugs unfortunately are never going to make it back to Kerbin in their current state, so a fuel resupply mission will need to be sent. We'll carry on with that soon.

[sadron]

Can you please tell me what mods you're using? I recognize a few, such as KW Rocketry, but others I'm unfamiliar with, but intrigued. Also I'd love if you shared some of your ship designs, I'd like to get a multipurpose interplanetary ship going. Right now our manned mission is fairly basic, just getting us there, landing, planting a flag and then returning home. Hardly of the caliber of what you've accomplished thus far.

[WhiteWeasel]

Hope you find one of the alleged of the KSP easter egg(s)? That may or may not be on moho. (take a closer look @ you map sat)

[DMagic]

Most of my designs use KW Rocketry for fuel tanks, engines, and fairings. Kosmos is used for the station components, the big grey parts and the trusses. It hasn't been updated for 0.2 though, so you have to add "scale = 1" to all of the parts in the .cfg file or else the connection nodes will be screwed up. A few parts are from KSPX, the big nuclear engine and a few small fuel tanks. I also use Sat Map, Quantum struts, nodeselect and Mechjeb. I've been playing around with a few other mods that I'll get to later, too.

I'll put up craft files later on when I have most, or all of them, ready.

Edited June 2, 2013 by DMagic

[DMagic]

Now that the station is complete the first order of business is to get some more fuel out to Moho so that the tugs can make it back.

A refueler was launched on my 50 ton lifter and sent on its way to Moho. I figured out a different way to do this launch. Instead of putting off the inclination change until I was in solar orbit, I launched into a 20^o inclination around Kerbin. Then I waited until I was near the descending node with Moho for the transit. Because I was burning retrograde I left Kerbin's orbit with a descending trajectory. My final orbit around the sun was only off from Moho's by about 1^o, so I was easily able to set up an encounter without any further inclination change.

While the refueler was on its way the Moho Orbital crew started working to identify the final base landing site. The next probe lander was launched near the south pole. It landed in a slightly more rugged, but still boring area.

This crater near the north pole looked like an interesting place to set down, seen here from orbit.

So the last probe lander was released and set down near the southern rim of the crater.

Next the probe rover was released to further study this crater. You can see the detachable lander system here as the probe approaches the norther region of the crater.

This area, just underneath a steep, long ridge could be a good base site. There is a good amount of flat ground and it should be mostly protected from intense direct sunlight.

Meanwhile, the refueler has arrived at Moho orbit. My strategy worked out pretty well. A total of just over 8800 m/s of delta-v was used from the surface of Kerbin to a stable orbit around Moho and a rendezvous with the station.

After docking to refuel, the tugs were released and set to return home. The fuel tug was able to bring about 1500 units of fuel, with about a third of that remaining at the station.

I waited for a launch window near a node with Kerbin and sent both tugs back home. Only a single burn was necessary, using about 2000 m/s for each tug.

After aerobraking at Kerbin both tugs made it back with plenty of fuel to spare. Once they get back to Minmus Orbital they will ferry the next station to Moho.

We'll carry on with the launch of the next station, its journey to Moho and assembly there.

[sadron]

Word of advice, just like the big orange tank, KW Rocketry's tanks hate rocket engines, you'll want to put a vanilla gray tank underneath it so the mainsails don't overheat.

[DMagic]

Yeah, I realized that, but I've found for the most part that it doesn't really matter. During the early stage of ascent I generally have to throttle back anyway. Overheating becomes a problem later on, but it's never prevented me from getting into orbit. It may not be as efficient, but I prefer the added stability of not having wobbly tanks on the bottom, and not having to put multiple struts on every booster to minimize that wobble.

That instability wasn't an issue when I was just using 4 boosters, like on the old 40 ton lifter. But when I put another pair on the 50 ton lifter I started having issues with the tanks colliding into each other. Struts helped, but the rocket was unpredictable and sometimes blew up. So I switched to putting the smaller tanks on top and haven't had an issue since then.

[sadron]

Even with KW Rocketry's heavier struts? I find that the slightly increased weight over the vanilla 150 strength struts is worth the thousands more strength. I usually go with medium as they're only twice the weight of vanilla struts but have thousands more tensile strength.

[DMagic]

I mostly use the regular struts, I think the ring of struts connecting the lower stage to the upper stage, attached to the small cubic truss pieces, uses the medium struts, but all of the others are stock. I don't think I've ever had a need for the heavy ones, but yeah, the medium ones can be really useful.

I'm not sure if I used the regular or medium struts on the bottom fuel tanks, but either way I prefer making designs that don't need so many struts. Most of these lifters have a single strut at the top of each booster and a ring of 4, 6 or 8 connecting the lower to the upper stage.

[DMagic]

Now we'll focus on the next station, Helios. Rather than rely on the intermittent sunlight near the pole of Moho for power, the base will be supplied by a large solar array located between the sun and Moho. This station calls for a plan similar to that used by Moho Orbital. The components will be launched to orbit around Minmus where they will be docked to the tugs and brought to Moho orbit.

The first launch is of the microwave transmitter array, used to transmit power from the station to the base on Moho. Launched on my 20 ton lifter, the array consists of a large dish and the central node for the station. That node is a modified version of the Kosmos 6-way node, I created an alternate version with 'rescalefactor=2.25' added to the .cfg file, this allows the large docking clamps to be used (all of the Kosmos parts need 'scale=1' added to fix the connection nodes). This was actually docked to Minmus Orbital a long time ago after a test launch worked well.

Next up the solar arrays were launched on my 15 ton lifters. Two of the components have docking clamps and 6 gigantor solar panels. The other two have the large Kosmos solar panels, which will generate the majority of the power.

All four components were then sent on their way to Minmus and docked, somewhat haphazardly, to Minmus Orbital.

Now for the last component, the habitation module launched on my 40 ton lifter. This consists of two cupola modules and a large crew space. The large module on the end is a solar shield, and there are extendable radiators on the sides. These parts are modified versions of the icarus mod.

Everything together at Minmus Orbital.

Once the tugs returned they were docked on the ends of their payloads.

After maneuvering the components into place the Hermes tug departs Minmus Orbital with the hab module and microwave array.

After wrangling all of the solar array components into place the Talaria tug departs.

Beginning the journey to Moho, Hermes ignites its engines over Minmus.

After a rather arduous journey both tugs made it to Moho.

And while they were able to establish an orbit reasonably close to that of Moho Orbital, they both ran out of fuel about 300 or 400 m/s short on delta-v. So another fuel tug had to be sent out before they could rendezvous at the station.

Just in case you were wondering, this is a craft that is way too long. If you plan on building something like this make sure it has lots of command pods or probe cores, because this has almost no torque, it takes about 5 to 10 minutes to turn this thing around. It is very stable though, there is no problem keeping it on course during burns.

Hermes docked to Moho Orbital and enough fuel was transferred for its return to Kerbin. The Helios components were then moved into their temporary configuration while awaiting the other parts.

And, finally for today, Talaria was wrestled into place at Moho Orbital.

Next up, we'll continue with assembly of the Helios station, the launch of the specialized tug to carry it into place, and its deployment there.

[Specialist290]

Most impressive

Wish I could assemble things that were half that impressive in orbit, but my computer huddles in a corner and whimpers softly whenever I even suggest the idea of something with that many parts.

[sadron]

Most impressive

Wish I could assemble things that were half that impressive in orbit, but my computer huddles in a corner and whimpers softly whenever I even suggest the idea of something with that many parts.

I have a feeling his chugs along too, he's just able to tolerate it for badass colony building.

[DMagic]

I have a feeling his chugs along too, he's just able to tolerate it for badass colony building.

Pretty much. I try to be really conservative with parts, that station has, I think, 88 parts without anything else docked to it. That's why I have all those ridiculous detachable docking systems. It really helps to keep the part count down. But even still things can get really slow, sometimes even when the part count isn't that high. Those solar arrays and the tug total about 200 parts, but it chugs along whenever I have to control those.

[jocax188723]

Brilliant-can't wait for the next installment!

[DMagic]

We'll start off today with a few more crafts that need to be sent down to Moho. First up is one of the two landers that will be used to ferry crew from the surface to Moho Orbital and back. Launched on my 15 ton lifter and commanded by Bob Kerman, this is a pretty simple craft, just a lander can and enough fuel to get down to the surface and back.

After that I launched Pyrois, named after one of the steeds that pulled Helios' chariot across the sky. This is the tug that will be used to push the Helios station into place. Parts used are from the tri-hexagonal structural truss set. The craft consists of four widely spaced LV-N's that will be secured to the solar arrays of Helios and placed between the central node and the hab section.

After meeting up in orbit the lander was docked to the front of Pyrois and they set off for Moho.

Meanwhile, back at Moho Orbital, construction of Helios began. The four solar array components had to be removed from the Talaria tug and put into place on the central node of Helios. My detachable docking system didn't work quite as well this time. For some reason the decouplers were giving a much bigger kickback to the solar arrays, making it hard to keep things aligned during docking. But I managed ok, and more impressively, actually kept everything rotated in the correct orientation. Here are a few stages of the construction.

And the completed station.

With the station complete, Pyrois arrives at Moho and enters an orbit reasonably close to that of the stations'.

After arriving at the station, Pyrois was temporarily docked to Helios while the ferry was moved into position on the hab module of Moho Orbital. The Helios hab module was then undocked and Pyrois slid into place.

Everything is completed and ready to go now, and of course, low on fuel. Moho Orbital is completely out, the ferry is running on fumes, and Pyrois is down to about half full. But at least the two tugs have enough fuel to get back to Minmus.

I'll be sending out much more fuel next, along with the second lander ferry. And Jeb and Bob will descend to the landing site to conduct their initial survey.

[sadron]

What's the mod name of those gray-blue station parts? I think you've mentioned it but I've forgotten.

[DMagic]

What's the mod name of those gray-blue station parts? I think you've mentioned it but I've forgotten.

Kosmos, it's just been updated for 0.2 so everything should work now, the connection nodes were screwed up before. The big 6-way node is from the same mod pack, but modified by me to fit the bigger docking clamps.

[sadron]

Technically it's 0.20, the twenty is deliberate, 0.2 would be like, pre-alpha XD I tease of course. Thanks for the information.

[Margaul]

Impressive. This makes me want to tool around with Moho sooner than I thought.

---

Margaul the Magnificent, Slayer of the Elevator Boss, Prince Ali, and the guy who always has his finger on the "talk" button.

[Specialist290]

Impressive. This makes me want to tool around with Moho sooner than I thought.

To that I say: Good luck, and pack plenty of delta-v. The most frequently used charts grossly underestimate the amount you actually need.

[DMagic]

After many, many trips down to Moho I've got it down reasonably well. From LKO I can usually get into orbit and rendezvous with the Moho station with about 5000 - 5500 m/s of delta-v. My best from LKO was just under 4500 m/s, but that was with launching into a 20^o inclined orbit, and a lucky encounter that required no further inclination change. From Minmus orbit I can usually get there with about 4500 m/s, I think my best is around 4200 or 4300 m/s, but starting at Minmus complicates things and I wouldn't recommend it. The only major advantage of starting from Minmus, is that you can really easily take care of the inclination change. A 20-50 m/s burn at Minmus can make a significant change in your Kerbin inclination, and if you time your burn near a node with Moho, that can take care of most or all of the inclination change. You can do the same by launching into an inclined orbit, but that doesn't help if you're already in LKO.

Mostly I don't bother with trying to get an ideal Hohmann transfer. I just do it like an orbital rendezvous, burning once or twice near periapsis and waiting for a good encounter. This adds to the total delta-v, but not by much, and I think it's much easier than trying to time everything perfectly.

Getting back, at least, is really easy. It pretty regularly takes about 2300 m/s to get into Kerbin's atmosphere. And that's starting from a polar orbit around Moho, which makes it a little trickier.