Operation Lavender - Stock 1.9/1.10 Eve Return Attempt

[Moss]

Hi all!

 

I’ve been playing Kerbal Space Program since 2013. I recently got back into it after the recent Breaking Ground and ESA-mission expansions, and thought it was about time to complete a couple of objectives that I’d never got around to doing over the years I’ve been playing. One of these is a crewed Eve return mission. This thread will showcase the designs and mission profile that I have used in my attempt. I present to you:

“Operation Lavender”

 

Part 1:

 

This thread is going to have a lot of pictures in it. Below we see the first one, showing the lift-off of the Eve lander.

 

 

It’s named “Orpheus”, after the Venus lander from the fun BBC Series, “Space Odyssey - Voyage to the Planets”. Orpheus is tucked inside the huge fairing and drained of fuel so that it can be lifted with the launch-vehicle, a Sun-Lifter Type 4. The launch vehicle is named because it uses 4 Mainsails for the first stage and 4 Skippers for the second stage. 

 

 

On its way to orbit, the fairing is exploded away to reveal Orpheus. This is by far the most complicated planetary lander I have designed in this game and also, when fully fueled, the heaviest. It uses seven LV-TX87 Bobcat engines, from the Making History expansion. One sits under a central core consisting of one FL-TX900 and one FL-TX1800 fuel tank. The remaining six are located on the detachable side-boosters, each an FL-C1000 fuel tank. These seem great for an Eve lander for several reasons. They’re really pointy, which I assume assists with the aerodynamic profile of the craft. They’re also heavier at the bottom than at the top, which should help make the lander more likely to remain upright on descent. Finally, they’re got built-in separation boosters, which should be helpful for reducing part count as well as making sure they jettison safely in the thick atmosphere of Eve. The tanks are asparagus staged in three pairs, with the last pair feeding into the core. 

 

The Bobcat engines were chosen based on a couple of simple criteria. First, they’re the right size for the fuel tanks. Unlike the Aerospike engines, they also have thrust vectoring. Finally, I scored each engine in the game by multiplying its ASL TWR (for the Bobcat, this is 187 N/kg, and yes, this is actually a thrust/mass ratio… but you get what I’m trying to do) with its ASL ISP (290 seconds), then dividing the number by 1000 for readability. The Bobcat scored 54.23. For comparison, the Aerospike engine scores 44.52, the Mainsail scores 65 and the KS-25 Vector scores 69, but I think the Vector is a bit overpowered. Besides, the real-life RS-25 is only as good as it is because it uses a hydrolox fuel mixture, and it seems ridiculous that you’d use such a fuel mixture on an interplanetary vehicle, much less in a superheated atmosphere like Eve. I believe the LR-87 was even made to run on hypergolic propellants! Not that any of this is actually translated into the gameplay balance of KSP, I just chose to play with this particular handicap. 

 

The final stage consists of the tiny nosecone, a Mk. 1 Command Pod, one FL-T200 fuel tank, a small/tiny adapter, and a Rockomax Spark engine. It’s wrapped partially in a fairing to be more aerodynamic. Some Eve landers I’ve seen just use the external command seat lawn-chair, but I’ve handicapped myself again by deciding that a descent into such a nasty atmosphere, at least for roleplaying purposes, necessitates the use of a command pod for a Kerbal. Since the lander doesn’t feature an RCS system, I did remember to drain the command pod of monopropellant to save weight. 

 

The lander features detachable landing legs, a detachable science module underneath the core, detachable parachutes, and an enormous detachable ladder. 

 

 

The next launch, on a much heavier launch rocket, this time a Sun-Lifter Type 12, delivers the massive nuclear transfer tug to orbit for docking with the lander. The lander and the tug will remain under robotic control for the journey to Eve, where they will be met with a crewed vehicle.

 

 

Here, the two vehicles are docked in orbit, waiting for the transfer window for Eve. The nuclear tug is a Type 4-8-8. It gets its name from the fact that it uses 4 nuclear engines, and 8 nacelles of 8 liquid fuel tanks. 

 

 

Another Sun-Lifter 4 launches the orange fuel payload for the lander. The lander requires a lot of fuel, 4455 liquid fuel, not counting the final stage, plus however much oxidiser. I think the lander is about 45t unfueled, and the fuel alone adds another 35t. 

 

 

The fuel payload is joined in orbit by another Type 4-8-8 nuclear tug. And with most of the hardware in orbit, that’s it for Part 1! In Part 2, we’ll meet the intrepid crew for this massive mission. 

 

[Moss]

Part 2:

In Part 1 we saw the design for the lander, Orpheus, and the launches of it and a refueling payload to Kerbin Orbit. With these ships positioned in orbit, the crewed Command vessel, “Lavender 1” was launched just before the Eve transfer window opened. 

Aboard are the three crew:

-Pilot, Gregby Kerman

Gregby was, in this save, the first Kerbal to set foot on Duna. He’s my most experienced pilot, and I’ve credited him with making a landing on Ike with very narrow delta-V margins, using only the remaining fuel from that same Duna mission. Fearless, strong and stupid, he’ll be attempting the first crewed landing on Eve. 

-Engineer, Tanby Kerman

Tanby was the first Kerbal to set foot on Gilly, having previously visited the Eve system to do so. She was also responsible for overseeing the landing of a rover on the purple planet. She represents the ultimate technical authority for all things Eve atmosphere/surface related on this mission.

-Scientist, Madwell Kerman

Madwell has only participated in one previous mission, a Mun landing that I’ve been using as part of a training program for new recruits. He’s mainly just along for the ride, mostly because I like his name. There won’t be much need for a scientist on this mission because Orpheus’ instruments won’t be used until they’re on the surface of Eve, after which they’ll be jettisoned. 

 

With Lavender 1 on it’s way to Orbit, the fairing is exploded away. Lavendar 1 is a standard interplanetary crewed vehicle of mine, with a Mk 1-3 command pod and two Hitchhiker Storage modules. 

 

 

The nuclear transfer vehicle is a Type 3-6-6. After some final checks, all three vehicles depart for Eve.

 

 

Months pass, and during that time I also had another Duna mission arrive at its destination (but that’s for another thread). Lavender 1 and the refueling payload arrive at Eve a couple of weeks before the lander due to me not being very good at plotting or executing departure manoeuvres. 

 

 

Once in a 200x200km orbit, the enormous refueling craft and Orpheus are rendesvoused to begin the fuel transfer. Because I’m a knob, I put the wrong sized docking port on the refueling pod. Orpheus has a Jr. sized docking port on the top girders that attach the “bunny-ears” heat-shields, whereas the refueling pod only has a regular-sized one. 

 

 

Fortunately, there’s a regular-sized port on the lander underneath the rear heatshield, so I docked to that. Refueling was actually quite annoying with the new fuel-transfer bug in 1.10. I make it a rule for myself to not use quicksaving or reloading, but I made an exception here to allow myself to reload the game several times until the fuel transfer controls behaved themselves. 

 

 

After a few orbits, Lavender 1 rendesvoused with Orpheus. Gregby Kerman transfers to Orpheus via an EVA. 

 

 

Once aboard, he begins system checks, making sure that the lander is full to the brim with fuel, and ensuring that the staging is correct, and hasn’t been affected by all the docking with other ships. 

 

 

Tanby and Madwell also perform checks on the spacecraft from the outside, and give the go-ahead for landing. They’ll be watching closely from up above. Gregby will have communications throughout all of the descent thanks to the relay satellite from the first Eve robotic rover mission. They wait unti Eve has rotated such that the majority of the daylit portion of the planet is land, and not sea. The nuclear tug will perform the de-orbit burn, bringing the periapsis down to 40km within Eve’s atmosphere, before separating from the lander (and now-empty refueling pod), and boosting it’s periapsis back above the atmosphere. 

 

 

The nail-biting descent awaits in Part 3! Gregby Kerman is about to perform one of the most dangerous flights ever attempted, for several minutes being only a whisker away from being shredded and reduced to vapour if Orpheus becomes unstable during the descent. 

[Dat Kerbal Dude]

Be carefull when Landing on Eve.

i've heard Eve's atmosphere is Quite Evil to everyone.

Suggestion:Use a Lander that can Throw away Empty Fuel Tanks to Save a lot Delta-V while Returning to the Orbital Command Module.

[Moss]

Part 3:

 

In this installment we’ll witness the terrifying descent of the Orpheus lander, piloted by Gregby Kerman, into the unforgiving atmosphere of Eve. The nuclear tug has lowered his periapsis to 40km over the largest portion of solid land on Eve. Since I don’t have a way of targeting descent trajectories in atmosphere, all I can do is hope that the lander will land on something reasonably high. Ascents get much more difficult from lower elevations on Eve, so we’re hoping that Gregby lands on a nice flat mountain. 

 

Once his altitude falls below 100km, he ditches the refueling pod and inflates the three heatshields. It doesn’t take long for the the atmospheric effects to become apparent, with orange plasma licking at the leading edges of Orpheus. 

 

 

The bright spot several kilometres in front of the lander is not the sun, it is in fact the refueling pod being vaporised as it descends. 

 

 

As the craft descends deeper into the thick atmosphere, it becomes engulfed in yellow plasma. Despite the “bunny-ears” heatshields at the top of the lander, it starts pitching over, exposing more of the lander’s sides. This is very dangerous - several of the parachutes start getting very hot very quickly, and there’s a real risk that if a few components start to overheat, the entire craft will be shredded. 

 

 

Orpheus has six detachable reaction wheels under the Bobcat engines, but they’re nowhere near strong enough to be able to control the pitch of the craft directly in this kind of atmospheric flight. Instead, Gregby is able to roll the craft about 45 degrees, which causes it to stabilise and re-align with its descent path. 

 

 

Once the lander stops being bathed in flames, the “bunny-ears” are detached. 

 

 

Parachutes are deployed to further slow the craft. Orpheus has 24 radial parachutes. It doesn’t have any drogue parachutes, since the atmosphere of Eve is so thick that it can do without them. 

The radial parachutes on Orpheus aren’t even configured in a fancy way. For Duna landings, in much thinner atmosphere, I normally tweak them to open at the highest possible altitude and at the minimum possible pressure. This actually caused enormous whiplash for Gregby and Necal on that first mission, and they blacked out for a good few seconds. This was not the case for Orpheus, which followed a very gentle ascent. 

 

 

Once the parachutes fully deploy at 1000m, Gregby releases the heatshield, but keeps a watchful eye on the altimeter, and the ground below. The entry heating has disappeared, but the danger is far from over. If it looks like the landing is getting too close to sea level, or the ground doesn’t look flat enough to land safely, Gregby will have to perform an emergency abort, and simply begin his ascent while ariborne. His mitt hovers over the staging button. 

 

 

Fortunately, the ground below is lovely and flat, but it’s at an elevation of 1500m. I was really hoping for something above 2000m, but Gregby’s made of sterner stuff than me, and touches down safely on the surface. 

 

 

Gregby exits Orpheus and begins his history-making descent to the surface. Climbing a ladder from this height, especially in a space suit, on a planet like this would simply be impossible for most people, but Gregby takes it in his stride. 

 

 

Gregby extends his foot down toward the purple sand…

 

 

And triumphantly marches away, taking the first steps onto Eve for any Kerbal in my history of playing this game. This is a big moment for me, and I’m somewhat proud to have eventually made it to this point. I can’t relax completely, however. We still need to collect the science data from the instruments, and we also need to be able to successfully return back to orbit. 

 

 

Climbing the ladder to deposit some of the science experiments, Gregby notices a small speck in the distance. I think this is the “bunny-ears” heat shield assembly, which must have taken a rather round-about descent path. It crashes into the surface about 5km away. 

 

 

Gregby plants a flag, the first flag ever for me to be planted on Eve. At this point I realise that the flag is wrong. Dangit! I designed Orpheus in a sandbox save file, where I never bothered to change the default flag, and forgot to do so when I copied the craft file into my career save. But Gregby doesn’t know that, and just chooses to enjoy the moment. 

 

 

He does some more science, and here we get a good close look at the underside of the lander, showing off the detachable science module, reaction wheels, batteries and probe core. Gregby can’t control any of the experiments himself, what with him not being a scientist and all, but he can run them from the command pod and then collect the data.

 

 

On descent, he noticed a funny looking grey thing on the surface, which could be part of his spacecraft, or it could be something exciting from the Breaking Ground expansion. He waddles heroically over to take a look. 

 

 

Turns out that it’s a piece of volcanic rock. I’m pretty lucky that we ended up landing so close to one, and Gregby is excited about its scientific value. Madwell, from orbit, advises him to take a sample. 

 

 

Gregby ponders whether or not it’s possible to fit the whole thing in the command pod with him, before settling for chipping off a small bit. 

 

 

Gregby begins his return to Orpheus, his only way off this hellish planet. The ascent is going to be very difficult, even for the Kerbal Space Program’s most experienced pilot. He’ll be relying on raw instinct and good engineering to make sure that he can successfully return to orbit, and not be pulled back into fiery death. The take-off is fraught with danger also - having to jettison so many components at the same time as firing the engines is a recipe for explosions, and one that Gregby simple has to hope won’t happen. In Part 4, we will find out the fate of Gregby- whether he becomes the first Kerbal to escape from the surface of Eve, or whether he perishes a hero, in a cremation of plasma. 

[Moss]

Part 4:

Gregby Kerman, our hero, after successfully having set foot on the surface of Eve for the first time in history, now returns to the Orpheus lander to attempt his perilous ascent.

He detaches the ladder.

…And then the parachutes, which violently explode on the surface of Eve. 

This is why I’ve been nervous about the ascent in the first place. Things tend to get twitchy on the surface of Eve due to the high gravity and dense atmosphere. Orpheus is meant to fire its engines to full throttle at the same time as it jettisons the decouplers connecting the landing legs. This means that there’s not an insignificant risk of some piece of debris bouncing off the surface and clipping one of Orpheus’ engines. 

Gregby closes his eyes, throttles to full, and presses the staging button. Things happened so fast that I didn’t get a chance to turn off the GUI before taking this screenshot. You can see the explosions happening underneath the lander as the discarded landing bits convulse and disappear in plumes of smoke. I’m not sure that the flag survived the chaos- I’ll have to go check later. There’s probably be one or two scorched landing legs left to mark the landing site anyway. 

Not long into the flight, the first pair of boosters runs dry of fuel. They’re discarded, and Gregby soars on upwards. With this lander, there’s no point in throttling down to try to conserve fuel early on. I originally thought that this would be a good idea, to minimise aerodynamic losses, but testing in sandbox revealed that it was best to just go full-throttle and punch through the lower atmosphere as soon as possible. “Pinch yourself and pucker up! It’s time to peel the paint!” - Roberta Draper, The Expanse. 

Soon after, the next pair is expended, and the mach effects are becoming very obvious now. Despite this, Gregby’s not pulling massive G-forces, this is just how the atmosphere works around here. 

The last pair is expended, leaving only the central core and the final stage. The flight profile that I found, through trial and error, to work best is a straight up ascent until an altitude of 30,000m, then pitch over to 45 degrees very agressively. 

It looks weird, being on fire at a strange angle, but it seems to give the best results. Gregby aims for full pitch-over to 90 degrees at 50,000m. 

When the central core runs out of fuel, the fairing is jettisoned to reveal the tiny final stage. Below are some concept drawings that I did before designing Orpheus - I must admit it was very exciting seeing it brought to life. 

The final stage begins its long burn to orbit. Now that the adrenaline-fueled terror of the atmospheric ascent is over, Gregby gets to enjoy the creeping dread of wondering if he has enough fuel to make it the rest of the way. 

On most other celestial objects in this game, on an orbital burn you can see the trajectory expand reasonably quickly over the surface of the planet as the periapsis lifts itself above the surface. This happens very slowly around Eve, and it was a tremendous relief when Gregby’s periapsis finally popped up above 100km. 

The camera angle automatically flips over, and we all breathe a massive sigh of relief. We’ve done it! We’ve landed a Kerbal on the surface of Eve, and safely returned them to orbit. And, with 430m/s of delta-V to boot! Gregby’s ecstatic. 

The original mission plan was to have Lavender 1 drop its orbit down in order to rendesvous with the Orpheus capsule. Instead, the remaining delta-V allowed Gregby to boost his orbit up to the 200x200km orbit of Lavender 1, and bring himself to a slow drift a few hundred metres away. 

Remembering to retrieve all the science data and samples, Gregby bids farewell to the capsule, which starts tumbling away slowly without him in control. 

Gregby returns to Lavender 1, bringing his thrilling adventure to an end. 

The crew fire up the Nuclear engines, sending Lavender 1 into a higher orbit. I think I’ll send them to Gilly as they wait for the Kerbin transfer window to open. For us though, that’s the end of this write-up. Hope you all enjoyed!