Eve return in 1.1.3 - Mission Report - Now complete with the return

[purpleivan]

Here's the tale of my 1st Eve return mission since v0.90. Links below to parts all parts.

Part 1 - Assembly

Part 2 - Outbound

Part 3 - Landing

Part 4 - Ascent

Part 5 - Return

 

Edited July 16, 2016 by purpleivan

[Wallygator]

Nice!

A fascinating ascent profile ;-)

[purpleivan]

2 hours ago, Wallygator said:

Nice!

A fascinating ascent profile ;-)

Well it was ascending all of the time, just not as quickly as planned a couple of time.

I brought Maxina Kerman back to Kerbin this evening and here are a few pics from the mission. Full mission report (with lots more pics) to follow later.

 

Docking the Eve Redux lander with one of the tugs in Kerbin orbit

 

Burning the outboard motors (more to be explained in the mission report) to descend to Eve surface

 

Maxina on the surface

 

Launch from Eve

 

Coming in to land on Kerbin

 

[Teilnehmer]

Hm… Why have you built it so unaerodynamic?

[purpleivan]

3 hours ago, Teilnehmer said:

Hm… Why have you built it so unaerodynamic?

Probably I should have considered aerodynamics more, but my last landing on Eve was in 0.90 when aero wasn't as big a deal as it is now, so it's shape follows roughly that of my older Eve landers, like this one.

[purpleivan]

So here goes with the mission report. As it's quite length and pics heavy I've broken it into five parts, with parts 1 and 2 posted today, the others to follow later.

Part 1 - Assembly

The starting point for the Eve Redux was that of all returns trips to Eve, lifting off from Kerbin. The vehicle weighed in at 687 tonnes on the pad.

 

A really smooth ride up through the atmosphere on a pair of Mammoths and onto the Rhino (a rare example of me using this engine).

 

With the Rhino stage exhausted a pair of Skippers complete the work of putting the lander into a 279km orbit of Kerbin.

 

With the Eve Redux safely in orbit it’s the time to send up  something to push the lander to Eve. Again a smooth by the numbers launch of a pair of nuke powered tug vehicles inside the fairing.

 

”Thar she blows”. The Eve Redux with the intrepid Maxisa Kerman onboard, is eager to get those tugs attached and to get on the move to Eve.

 

Here comes tug number one.

 

Docking this was more challenging than normal as there was very little clearance between the lander and the fuel tanks of the tugs.

 

Ok… time for tug number 2. Unfortunately we’ve passed into Kerbin’s shadow, fortunately the tugs are equipped with lights.

With the docking of the two tugs complete, the vehicle is ready for the trip to Eve.

 

Edited July 5, 2016 by purpleivan

[purpleivan]

Part 2 - Outbound

With the tugs docked to the lander and the launch window arrived, it’s time to burn for Eve.

 

After about five minutes of the outbound burn it was time to drop four empty liquid fuel tanks from the pair of tugs. Eight more of these 400 unit tanks to go, plus 720 units in the center tanks on the tugs.

 

Ok… we’re on our way to Eve. Just need to tighten up the approach and align to the plane.

 

Leaving Kerbin in the rear view mirror Maxisa settles in for the long wait until the plane alignment and course correction burn.

 

Well here’s that burn.

 

With the burn completed the approach to Eve is much improved.

 

The mission plan was to separate the tugs from the lander just after the plane alignment burn, to allow them to dock together and have all fuel and monopropellant (never know if you’re going to need that last bit of thrust) from one to the other.  The fueled tug becoming the return vehicle to bring Maxisa back to Kerbin, while the other would sail on past Eve. After the fuel transfer and undocking, the return tug made a small burn to change its trajectory to Eve, delaying its arrival there until four hours after the lander, to give plenty of time to get that into orbit, before switching attention to the tug.

 

After millions of kilometres and several hours of gameplay, this is finally it!

Eve awaits.

 

At about 5km/s the Eve Redux slammed into the atmosphere of the purple giant. The PE was set to 72km, so it was nice to have that big inflatable heat shield up front. This altitude allowed for aero capture without consuming fuel, placing the Eve Redux in an elliptical orbit, while attention focused on doing the same for the return vehicle.

 

Four hours after the Eve Redux’ red hot aerobraking it was the turn of the return vehicle to get into Eve orbit. Unfortunately this vehicle was not designed for a fiery pass through Eve’s atmosphere, so it’s trajectory had it skim it at 89km. This did require however that some fuel be consumed to bring it into a highly elliptical orbit.

 

With both vehicles in orbit it was time to manoeuvre  the Eve Redux into a more suitable orbit for a controlled entry. However it was at this point that a serious problem was discovered, that would prevent a descent to the surface.

Will the kerb's fix it or just quit early for lunch and not bother... find out in Part 3 “Landing” (I guess the title's a hint)

Edited July 6, 2016 by purpleivan

[purpleivan]

Part 3 - Landing

After one more dash through the atmosphere to bring the elliptical orbit into something a little more circular, was that when I fired up a pair of the Vector engines to adjust my orbit, so that my next pass through wouldn’t send me crashing to the surface, nothing happened.

Oh the engines lit up fine, but all I did was burn fuel, with no change to my trajectory.

Hmmm… strange I thought. Why could that possibly be? Then a thought occurred to me.

As my engines were behind the protective shroud of the inflatable heatshield, perhaps the modelling of the thrust from them was being negated by the ejected mass hitting the inside of the shield, pushing the vehicle backwards with the same thrust that was pushing it forwards. I thought it unlikely, as it seemed a little too realistic (assuming that it would actually behave that way in reality), but I thought I’d test this by Hyperediting another lander into Kerbin orbit, and firing the engines before  deploying the heatshield.

Lo and behold the vehicle behaved as normal with a rapid change in velocity.

Ok… what to do next… this is what.

I decided that rather than scrap the whole mission, I’d do an “in place update” by hyperediting a new version of the lander into Eve orbit and editing the save file to put Maxisa in the driving seat.

“CHEAT” I hear you cry… “Shame, shame on you”.

Ok, strictly speaking it’s cheating… or as I prefer to call it, not wasting an entire evening doing “almost” exactly what I did the one before, so I decided to go with my ever so cheaty “plan B”

The new lander came with a couple of small outrigger engines attached to the base that I would detach and then use the AGU’s on them to re-attach to the fuel tanks above the useless Vector engines (but with access to the fuel they contained).

 

I didn’t bother putting any solar panels on the outriggers, so I had to be quick about getting them re-attached to the Eve Redux.

Once both were attached, I detached the gantry that they had been connected to, leaving me with my original vehicle, with an un-deployed inflatable heatshield and a couple of outrigger engines that sat outside the protective envelope of that heatshield once deployed.

I could have just not gone with the outriggers and instead just fire up the Vectors as originally planned, now that the heatshield was not “getting in the way”, but that seemed like a cheat too far.

 

With my new configuration of vehicle in place I had the means to adjust my orbit to make a few more passes through the atmosphere above a “you’re going down to the surface right now” altitude.  Once I was in a more appropriate orbit for a descent, I set a  manoeuvre node with a PE of 35km then deployed the heatshield

 

Then I lit up the outriggers at the appropriate time and waited for the Eve atmosphere to do the rest.

 

As expected the Eve atmosphere did a good job of quickly decelerating the Eve Redux and the speed quickly fell off.

 

In the process the outriggers, their usefulness at an end, burned off with the expected firework display.

 

Ok… now were back on the original track, with the heat shield deployed and the pair of Vector’s behind it ready to slow the lander at the very end of the descent.

 

Ok.. I forgot how deep the atmosphere on Eve is, so I’m still here burning down to the surface.

 

Finally the vehicle slowed enough for it to pitch over into a more vertical orientation and I remembered that I have airbrakes on this thing, so they were deployed.

 

Getting close now, so it’s time to deploy the chutes, which I did about 2.5km above the surface.

 

With the heatshield detached it was possible for my Vectors to have some kind of purpose, in this case bringing my lander down to a nice slow touchdown.

 

Congratulations all round to the guys back at the KSC, the Eve Redux is on the surface of Eve.

But what’s this… why are my chutes still deployed… it’s not stopped moving, that’s why.

Yep, I’d landed on a slope, not a steep one, but steep enough with the new physics to have the vehicle slide along the ground at 0.5m/s which meant that my vehicle thought they still had a job to do.

 

Finally, after all the sliding, the twisting around I made to the vehicle and probably hitting a marginally flatter bit of terrain, the Eve Redux came to a halt… well, almost. It was still moving at about 0.1m/s, but that was slow enough for the chutes to disappear and for me to be able to make a quicksave.

With the lander “stabilised” the drills were deployed and the Convert-o-Tron 250 fired up to brew Maxisa some tasty fuel for the trip home. With them doing their part for the return journey, Maxisa went outside to taste the Eve air (something she quickly decided was a bad idea before jamming her helmet back on) and planting the obligatory flag.

For the eagle-eyed among you, this is the point where I fired up my game with Stock Visual Enhancements installed... I'm a now big fan.

 

Here she is getting that all important “me and my lander photo” that the people back home always want to see.

 

While here she can be seen in a close-up of the ISRU gear going about its all important work.

Finally she climbed back into the Mk2 lander can at the base of the vehicle (I made sure to include one here as it meant not attaching a ton of ladders, as I had on my previous Eve landers) transferred to her home at the top of the Eve Redux and settled in for the long wait for the trip home.

Edited July 6, 2016 by purpleivan

[purpleivan]

Part 4 - Ascent

After much waiting…. well… warping, the mining was done.

The Eve Redux was fat with fuel ready for the climb up through the soup to orbit.

 

First thing to do is to drop the mass of all those parts connected to the upper part of the lander, that won’t be needed for the ascent, these being the parachute packs and the “tail” of aero parts that steadied the vehicle during its decent. This was accomplished with the help of a Sepratron on each of the sections to be detached.

 

It took a few seconds, even with the Sepratrons pushing the sections outward from the vehicle, due to the density of the atmosphere at  about 1km ASL, but eventually all of them cleared the vehicle and fell to the ground with a satisfying fireworks display.

 

Ok, all those bits are safely detached and not snagged on anything that’s about to go zooming upward. Sorry for all the litter Eve. The ISRU components separated from each other as well for some reason at this time.

I had hoped to leave them on the surface as a functional fuel generation base, but oh well.

 

Light ‘em up!

All engines at the base of the vehicle, 5 Aerospikes, four Reliants and 4 Vectors rapidly push the ascent vehicle away from the ISRU base of the lander.

 

With the Vectors providing a lot of directional thrust the vehicle was pretty easy to straighten up after launching from the slope that had been the Eve Redux’ home for the past few months.

 

Time to drop the Vectors and the big tanks that have been feeding them after they’ve helped to punch the vehicle up 6km. Maxisa looks very concerned, maybe she knows something I don’t.

 

At close to 16km it’s time to drop the first set of four Reliants. This went smoothly and the vehicle has good speed; things are looking good.

 

Ah… should have kept my fat mouth shut as this is not so good.

When I started to ease over the angle of ascent at about 26km, it pitches over way too far and I cut the engines

It rolled around twice, each time I’d fire up the Aerospikes when they were pointing within about 45 degrees of the intended direction, so that at least some effort was still being made to get this thing where it needed to be

I’d put small fins on the outer group of aerospike stages, but I messed up somehow and only attached them to one side of each tank, which most likely didn’t help.

 

By the time it’s ascended to 34km the Eve Redux finally is stabilised with the remaining 5 engines continuing to push it on towards orbit.

Phew! At least it’s survived this little mishap.

Once it’s into the mid 40’s km the speed of the vehicle is giving it a nice red fiery glow.

 

Time for the penultimate staging, with the dropping of the four outer Aerospikes.

Things are looking good.

 

As I try to adjust the ascent trajectory of the vehicle it pitches forward once more, spinning around four times, so it’s back to turning the engine on and off at the appropriate times, to keep the right movement going.

Between 60 and 90km the vehicle is virtually un-thrusted, but hey… let’s see how this turns out.

 

Finally out of the soup and thrusting parallel to the surface now.  Things are finally looking up… or sideways… or something.

 

The camera flips round about the vehicle… it’s in orbit.

 

There’s still fuel in the Aerospike stage and I leave that to burn until I’ve pushed out the AP to 443km. Time to separate the final stage.

 

Er… not so fast, it’s empty. Don’t know what happened there as it was full at takeoff.

 

Time for a little fuel transfer, so I drain the Aerospike stage fuel into the tank for the final stage powered by a pair of Twitch engines. Enough fuel to half fill its tank.

 

After separation we’re left with the tiny upper stage of the ascent vehicle, but we have plenty of fuel for circularising the orbit and rendezvous with the return tug vehicle.

 

Back on the surface at the launch site, the Eve Redux has left a healthy collection of kit for any local scrap merchants.

At least the Eve Redux itself is safely in orbit now in one piece.

Edited July 9, 2016 by purpleivan

[purpleivan]

Part 5 - Return

So with Maxisa in the Eve Redux in a safe although not quite circular orbit, it was time to get the return tug into something more useful orbit-wise as well.

 

It had been left in a highly elliptical orbit, which just missed the atmosphere, so the first thing to do was to bring it into the atmosphere for a little aerobraking. With the PE set at about 88km, the tug passed into the atmosphere with little affect on its AP, so the pair of nukes on-board were started to pull the AP in.

 

That’s a bit better. But how deep can the tug go on the next pass without getting too hot, so I adjusted the orbit to a PE of 86km. This is turned out was about as low as I could go without risking detonating the tug.

 

 

Even at this altitude the more fragile components were at risk of exploding due to overheating.

 

My solution was to tumble the vehicle occasionally, to allow the cooler components to take the heat, while giving the hotter ones a welcome break.

 

After a couple passes through engaging in this little tumbling act, I realised that I didn’t really need two of everything, so I decided to sacrifice a solar panel and battery on one side of the vehicle, to give me an easier life protecting the remaining ones.

Sacrifice of the components to the Eve goddess of massive atmospheric heating was by fire.

Typical explodery results as the little solar panel detonates its hidden stores of dynamite.

 

After many, many (I think about a 10) passes through the atmosphere at 86km, the AP was reduced to 1429km, so with some fuel remaining in the Eve Redux and my patience with the whole aerobraking thing wearing thin, I decided I’d circularise the tug at the AP and have the Redux meet it there.

 

So Maxisa gunned the engines and adjusted the orbit of the Eve Redux to a circular 1121km one.

 

Then it was time for the Tug to circularise its orbit.

 

That’s better.

 

The Maxisa made the necessary burns to arrange a rendezvous with the tug.

 

And there it is!

Good thing too as there is precious little left in the Eve Redux’ tanks.

Time to EVA over Eve, to get to the more spacious accommodation on the tug.

 

With Maxisa safely on board and after a little warping to get into the transfer window, it was time to set the burn for home.

 

See ya Eve.

 

After a course correction the Eve Redux was set for smacking into the Kerbin atmosphere at an altitude of 60km, although the approach was a little less equatorial than normal.

 

Hi Kerbin. Looking beautiful as always.

 

Just before grazing the atmosphere Maxisa had this nice view of home.

 

As well as aerobraking, with plenty of fuel left in the tanks, it was time to light up the nukes again.

 

Nice!

However almost the whole of the daylight part of the orbit was over water and I wanted to bring Maxisa in on land.

 

Only one thing for it then… BURN TIME

Adjusting the angle by some 20-30 degrees took some doing, so there wasn’t a lot of fuel left after the adjustment to the orbit.

 

With the adjustment done, time to make the re-entry burn.

 

Followed a little later by the friction burn.

 

Then much more burning.

Good thing these components are so well built.

 

Well… except for the nukes which exploded, but hey… their job was done anyway.

Nice view for Maxisa to enjoy as she heads down on the chutes.

 

Almost there., just time for a last look out of the window before touching down.

 

Home again.

Edited July 16, 2016 by purpleivan

[Geschosskopf]

Nicely done.  It's a good design that can get backwards on an Eve ascent and still make it.

And lots of explosions

 

[purpleivan]

On 18/07/2016 at 5:28 PM, Geschosskopf said:

Nicely done.  It's a good design that can get backwards on an Eve ascent and still make it.

And lots of explosions

 

At least the explosions didn't happen when it was going backwards.

[TopHeavy11]

Awesome. Your piloting skillz r so much better than mine.