Kron series (Kron 6 end of mission) - temporary halt of program

[DMSP]

4 Seconds!

4!!!

Wow.

[Zaddy23]

The Dv required will be crazy.

[lajoswinkler]

I know the required delta v. It's over 20 km/s and less than 20.5 km/s. I've confirmed that a long time ago.

That is a problem, though. It's the requirement to get from Kerbin to low Ablate orbit. But Kron 5 needs to return home, and that's where the main issue is. What will it be? 35 km/s in total?

I'm not even sure if I will be able to use a Taurus HCV capsule. This is a fantastic amount of delta v. Maybe if I send resupply tanks, maybe...

Catching Ablate will not be possible by falling from Kerbin. Deceleration would have to be stupidly high. I mean, the thing flew by like a rock thrown at the probe. Last time I went to Ablate, it had to be done from an orbit lower than Moho's.

[Zaddy23]

Last time I went to Ablate, it had to be done from an orbit lower than Moho's.

Maybe put a refuelling station in orbit around Moho, and then take Kron 5 and refuel at moho before continuing on to Ablate?

EDIT: or maybe even have some form of refuelling system built in to Kron 5 so that a lander can land, start mining, launch again, and when Kron 5 is in Ablate's shadow you can convert the ore to fuel (since last I heard the converters produce heat like crazy.)

Edited August 6, 2015 by Zaddy23
:p

[Geschosskopf]

I know the required delta v. It's over 20 km/s and less than 20.5 km/s. I've confirmed that a long time ago.

That is a problem, though. It's the requirement to get from Kerbin to low Ablate orbit. But Kron 5 needs to return home, and that's where the main issue is. What will it be? 35 km/s in total?

I don't have the extra planets mysself but doing a gravity brake off Eve en route to Moho saves a lot of fuel when it comes to the capture burn (not so much on the transfer there due to still having to burn to change planes to some extent). I suppose the same would be true for Ablate. Then come home via gravity acceleration off Eve.

[Yukon0009]

4 seconds? Is Ablate that small?

[GabrielG.A.B.Fonseca]

It's not a matter of Ablate's size...

... It's a matter of orbital speed.

*Dramatic Zoom*

[meve12]

This will explain it.

Oh THAT darn meme.

(Stupid swear filter.)

[lajoswinkler]

Thanks all for the suggestions, I'll take them all into consideration. Yes, Ablate is tiny. Equatorial radius is 13 km, basically same as Gilly, but it's a lot denser than Gilly. Its surface gravity is 0.36 of Kerbin's. It's not an asteroid pile of rubble like Gilly, but a Vulcanoid body.

Ikar 2, an Ablate orbiter, has been launched.

Second chemical stage firing.

Third nuclear thermal stage.

Fourth ion stage. Kerbol is already very close.

It is still firing and currently it's lower than Moho is. 1.25 million kilometres is a nice starting point for catching Ablate, but I might go 1 million if that doesn't work.

I'm beggining to feel this is too big of a bite. In fact I'm sure the ship won't be able to reach the target and return home without refueling. It will be the first Kron ship that actually needed refueling.

[Geschosskopf]

I'm beginning to feel this is too big of a bite. In fact I'm sure the ship won't be able to reach the target and return home without refueling. It will be the first Kron ship that actually needed refueling.

I'm not surprised at all. I never send returning ships to Moho without refueling capability because the chances of needing it far outnumber the chances of doing without it. And Ablate is an order of magnitude worse than Moho. So I hope the Ikar 2 has some resource-scanning capability .

[lajoswinkler]

So this is how things are.

1) Catching Ablate stomps on the "delta v is the only important thing" chant. Even when starting with 1 million km, passing through Ablate's SOI last for a few minutes which is not enough time to brake. If you want ion engines, you need to approach it as if you're doing a rendezvous with a craft around Kerbin.

2) Delta v is simply enormous. It's sick, perverted. Because of 1) and 2), I had to cheat a bit or few hours in front of the screen would go to waste.

3) Temperatures are absolutely crazy and stock radiators are useless. The whole stock heat management falls apart when you're in orbit. At first, shaded temperatures of 950 K are encountered, but after a few orbits at 1x (each lasts for 9 minutes at 3 km height), temperatures over 2500 K build up. I think those are some kind of errors.

Anyway, without disabling heat damage, Ikar 2 would turn into a rain of junk.

If Nertea's Heat Control fails to provide enough cooling to keep the tanks below 1000 °C (1273 K), Kron 5 will not be possible.

Ikar 2 found out Ablate has a pretty decent induced magnetic field which is expected from a rocky body. It contains metals and is immersed in an intensive solar wind so that simply must happen.

[Jodo42]

I'm not 100% sure, but a bi-elliptic transfer might be useful in this scenario to shave down the dV by a few km/s.

The Solar Flare challenge thread might be useful to take a look at some of the engineering requirements of low solar missions like these in terms of fuel, flight planning, and dV.

Likewise, the Solar Limbo challenge thread might give some inspiration on how to deal with the heating.

Edited August 8, 2015 by Jodo42

[lajoswinkler]

Delta v is less of a problem. It's incredibly difficult, but manageable with good logistics.

There are two issues:

1) heat by itself - fuel tanks hold up to 1000 °C and that's around expected temperature around Ablate and on its surface. Unless Heat Control can hold it couple hundred degrees lower, nothing will help. The propulsion unit will explode.

2) heat under timewarp - strange, bizzare things occur if you go over 100x and you simply must if you don't want to run the game for a week. Temperature spikes, constant temperature buildup even in Ablate's shadow, spontaneous explosions. My only solution would be shutting down heat in the cheat window during the timewarp. If the game is cheating on me, I will "cheat" the game. I honestly wouldn't care in that case.

Oh, regarding the bielliptic transfer, I understand how that goes. It would be a reverse one. Pushing apoapsis higher than Kerbin, coasting to it and then lowering periapsis, and finally coasting to periapsis and lowering apoapsis. It's neat, but there are two problems. First is the time needed to do it, food (I use TAC) and mass (food and/or Deep Freeze module which is not temperature resistant). Second is maximum possible acceleration. Speeds encountered near Ablate are insane. Unless you want rolling around Kerbol and shedding speed each time you get to periapsis, you need to do it at once with a powerful engine.

While I'm still running Kron 4, I'm designing Kron 5 and this time I'm almost 100% sure it will not be a 3.75 m ship, but a 2.5 m one, with stock capsule. The opposite would be a lesson in really sick grinding. I don't want that. Fueling up the ship in LKO is enough grinding by itself, I don't need more.

[Geschosskopf]

There are two issues:

1) heat by itself - fuel tanks hold up to 1000 °C and that's around expected temperature around Ablate and on its surface. Unless Heat Control can hold it couple hundred degrees lower, nothing will help. The propulsion unit will explode.

2) heat under timewarp - strange, bizzare things occur if you go over 100x and you simply must if you don't want to run the game for a week. Temperature spikes, constant temperature buildup even in Ablate's shadow, spontaneous explosions. My only solution would be shutting down heat in the cheat window during the timewarp. If the game is cheating on me, I will "cheat" the game. I honestly wouldn't care in that case.

I agree. It's sort of the same as aerocapture being broken at all non-Kerbin planets with significant atmospheres due to their atmospheres behaving as if they were oceans. There is no shame in working around bugs.

[Cydonian Monk]

What's Ablate's orbit exactly? 650Mm? I've noticed that operating much below Moho's orbit is really tough with the latest heat changes, and the only two probes I've sent to "Low Kerbol Orbit" (~1Mm) have both had things explode. Those were all before radiators were a thing, though I don't think the folding-type radiators would've helped in my case (too heavy). And of course the non-folding radiators only pull heat away from the part they're connected to.

Mad props if you manage to send kerbals there and they don't melt.

[lajoswinkler]

I agree. It's sort of the same as aerocapture being broken at all non-Kerbin planets with significant atmospheres due to their atmospheres behaving as if they were oceans. There is no shame in working around bugs.

Sarnus is the only planet that supports aerobraking... barely. Granted, I used Deadly Reentry and 120% settings, but as I've heard, even just stock heating set up to the minimum doesn't allow aerobraking at Urlum after Hohmann transfer. This means that going to Neidon will require hyperbolic trajectory and engine braking.

What's Ablate's orbit exactly? 650Mm? I've noticed that operating much below Moho's orbit is really tough with the latest heat changes, and the only two probes I've sent to "Low Kerbol Orbit" (~1Mm) have both had things explode. Those were all before radiators were a thing, though I don't think the folding-type radiators would've helped in my case (too heavy). And of course the non-folding radiators only pull heat away from the part they're connected to.

Mad props if you manage to send kerbals there and they don't melt.

648 thousand kilometres, more or less, yeah.

I've used Hyper Edit to put an Mk1 capsule with Jebediah on Ablate's sunny side. After exiting, it took 27 seconds until he overheated and exploded in a gray of puffy smoke.

Danilon62 is helping me design a rover, but something tells me this will not work.

[Windspren]

Maybe try the Heat Control mod that's not Nertea's, which has Active Coolers. Also, have you tried a "sunshield" with radiators on the edges?

[lajoswinkler]

It appears you can't shield yourself from the radiative heat as you can block the light from the solar panels.

Kron 4 has entered the orbit around the last planetary body in Urlum's system, Priax.

It will stay in an eccentrical, polar orbit for a while, and then settle to a circular one.

[lajoswinkler]

This is the last mission of the Kron 4 team - landing on Priax.

Bob picked up a really deep crater to sample the depths of it, as well as its rim. Kerpernicus lander will also be shielded from most of Urlum's ionizing radiation here.

The first to come out was Bill because why not?

Priax is kind of like Gilly, only with more darkness, less heat and more ices.

This crater floor is a world on its own. It probably has permanently shaded areas and looks cozy, protected. Valentina is deploying a flag.

Kerpernicus landed between two rocks, one of which was particularly huge. Good for Bob's research.

[Mister Dilsby]

That crater is amazing! Hm, I wonder if it's deep enough that the gravioli detectors can pick out the effect of the walls' mass?

[Geschosskopf]

Nice job and congrats to the Kron 4 team for completing their mission. I wish them an uneventful and speedy voyage home (and hope they have a good way to stop at Kerbin).

[lajoswinkler]

That crater is amazing! Hm, I wonder if it's deep enough that the gravioli detectors can pick out the effect of the walls' mass?

In reality, it would be possible.

Nice job and congrats to the Kron 4 team for completing their mission. I wish them an uneventful and speedy voyage home (and hope they have a good way to stop at Kerbin).

It's a long way home. The ship needs to be prepared, junk removed.

But first, Bob needs to sample the crater rim.

With Urlum's reflection on his visor, and bathed in its radiation, Bob quickly picks up few rocks. Crater rim is staggering 7750 m above its floor, taller than the tallest point above the sea level on Kerbin.

Inner Kerbol system is visible in the distance.

Time to come back. One jetpack is enough.

Bob, Bill and Valentina posing on their last mission.

Neutron reflectance instrument is left on the surface.

[DMSP]

Wow.

Can't believe this is almost over...

[lajoswinkler]

After the transfer of resources, Kerpernicus has been shut down and Bill pushed it away from the ship.

The science lab module was detached,

And the ship reassembled.

A short burn was made to get away from Priax and then to lower the periapsis closer to Urlum. Two of the final upper stage lateral tanks have been spent.

Kerty calculated the optimal approach. Urlum will provide an Oberth effect, and Wal will be used as a slingshot so that the resulting Kerbol orbit speed will be decreased. I think it reduced the delta v consumption by some 300 m/s.

Falling to Urlum, stand by.

Edited August 15, 2015 by lajoswinkler

[CaptRobau]

Lajos you are discovering things that I never knew about. Like the depth of that crater.