Long-term Laythe Mission (pic heavy) - ^_^ With Part 45 ^_^

[Brotoro]

Valley: Thanks for the rover autopilot explanations.

Also... I am an American. It's possible to use proper English even if you live in the U.S.A.

[DaserTheGamer]

Valley: Thanks for the rover autopilot explanations.

Also... I am an American. It's possible to use proper English even if you live in the U.S.A.

Yep. Also, Brotoro, what do you think that will happen to saves when the new aerodynamics model comes?

You may want to back up your save before 1.0.

[Deddly]

You may want to back up your save before 1.0.

Don't worry, he has a solid method for backing up his save files He doesn't only do it when updating, he also does it on a regular basis.

[Brotoro]

Long-term Laythe - Part 44

Curing Comsats

Recently I've been concentrating on my Developing Duna mission and a new Exiting Eve mission, so I've been assuming that the guys on Laythe have been keeping themselves busy. But Kerbal Alarm Clock reminded me that the ship for fixing the Laythe Comsats was approaching Jool and needed to be handled first...so I'll do a quickie report of that mission.

As you may recall, all of the comsats in the Jool system were broken when the 0.90 MeV Beta Particle Storm hit, destroying the reaction wheel capabilities of the OKTO 2 probe cores. This mission is to refurbish the Laythe probes and deliver some replacement comsats that could potentially be moved to the other Joolian moons as needed.

Below, the Standard Nuclear Tug carrying the comsat payload performs a plane shift burn, which happened to be very close to Jool's sphere of influence. Also built into that maneuver (planned shortly after the ship left Kerbin's SOI) were some small prograde and radial components to target the ship on a tangential intercept with Laythe that would result in aerocapture by Laythe. Note MechJeb's Landing Guidence display that shows the expected orbit after aerocapture (this was tweaked using RCS after the ship passed into Jool's SOI to give a Laythe apoapsis of 3,000 km).

In the upcoming universe of KSP 1.0, which will include aerodynamic heating effects, the question of how to get captured at the Joolian system becomes very important. In the old days, I used to aerocapture in Jool's atmosphere (rather than in Laythe's). My thinking was that when using an atmosphere to come screeching into orbit, it would be less violent to slow down over a distance of thousands of kilometers in Jool's atmosphere rather than slow down over a much shorter distance of hundreds of kilometers in Laythe's atmosphere. But this turns out not to be the case, for reasons given below.

First, you pick up more speed dropping down to Jool than just dropping down to Laythe's orbit. Second, Laythe is moving in its orbit, which increases the distance over which you are slowing down...and you only have to slow down to Laythe's orbital speed. Add to this the fact that you don't need to use additional fuel to intercept Laythe and brake into orbit (as I did after a Jool aerocapture), and aerocapture directly at Laythe becomes even more desirable.

But, to ensure minimal aerocapture heating, you need to do a couple other things. One: You want to make sure your ship's intercept trajectory with Laythe is as close to tangential to Laythe's orbit as you can make it; this minimizes the relative velocities (by quite a bit in some cases). You can do this by tweaking the prograde and radial components of your distant targeting burn (while focused on the Jool system to see the results) so that your ship will arrive at Jool when Laythe is in the correct part of its orbit. Two: Adjust your aerocapture altitude as needed to put your ship into a highly eccentric orbit around Laythe; this also minimizes to aerodynamic heating by minimizing the aerocapture delta-V. You can then use multiple aerobrakings to lower the orbit.

All of this depends on having a good aerobraking calculator. I use the one built into MechJeb's Landing Guidence feature, but I gather that there are aerobraking calculators online.

Below: The Comsat Refurbishment ship drops in toward Laythe. I apparently hadn't handled my plane-matching burn outside of Jool's SOI too well, since the ship is coming in from below the plane of Laythe's orbit. I not sure how I messed this up...but I apparently hadn't done the burn to match Jool's orbital plane right at the node (I don't recall if I used Kerbal Alarm Clock's opinion of where the node was, or using the marker in Map view...I should have double-checked as that burn approached).

The ship got as low as 26,160 km during the initial aerocapture, and the entry flames were unimpressive (as desired).

Below: A burn of 279 m/s was needed to align the ship's initial post-aerocapture orbit with Laythe's equator. Unfortunately, the nodes were both close to Laythe, so the burn was relatively expensive. This could have been avoided had I done a better job out in deep space matching the orbital plane of Jool.

Note: You might notice that the Map View above doesn't show all the orbital and surface assets that I have at Laythe. This is because, for reasons of lag reduction, I do my orbital assembles in Kerbin orbit and interplanetary transfers is a separate copy of my savegame file with fewer ships (the main savegame file has over 200 active ships, landers, bases, etc., which can bog down KSP). After the Comsat Refurbishment ship got into a stable orbit at Laythem I copied and pasted it into the main savegame file.

At apoapsis, a small burn of 1.4 m/s was made to lift the periapsis a little for an aerobraking pass that would drop the apoapsis near 1,000 km where the stricken comsats are located.

After the aerobraking pass, a burn of 293.2 m/s was needed at the new apoapsis to almost circularize the orbit. "Almost," because a slightly elliptical orbit was used to create an intercept with Laythe Comsat 1 upon the ship reaching its next apoapsis.

Below, the ship rendezvous with Comsat 1 in a 1,000 km circular orbit above Laythe.

For extra fun and excitement, the first thing I did to Comsat 1 was give it a bump to get it slowly tumbling. Then I backed off and changed position and then tried to dock. First I gave a few little bumps to try to minimize the tumbling...then docked. The magnetic docking force is strong with this one, being rather small in mass.

After docking, I saw that the RCS fuel was down to 79%...which seemed to indicate that I had used a lot more monopropellant than expected...though this does include monopropellant used during the interplanetary transfer targeting. But still...this seemed like a lot to have used. Maybe I forgot to top off the RCS tanks during the refurbishment of the Tug.

Anyway... The central spire on the nose of the ship is a stack of: Jr. Docking Port - Small Reaction Wheel - Jr. Docking Port - Jr. Docking Port - Small Reaction Wheel - Jr. Docking Port...etc. The reaction wheels in that stack had been deactivated previously to keep the stack from wobbling around during maneuvers...so before the comsat was released, its new reation wheel had to be activated, and then the comsat was separated with its shiny new reaction wheel in place (and a docking port still on the end for future refurbishment, if needed).

Then it was off to Comsat 2 by kicking the Comsat Refurb ship in a slightly higher orbit (just its apoapsis) to wait for the next comsat to move into position for a rendezvous.

The remaining three comsats were still aligned Normal, and I didn't bother to bump them off kilter to force docking with a tumbling object (I'd already had enough of THAT fun). Below, the docking with Laythe Comsat 2, and the subsequent separation of the comsat with its spiffy new reaction wheel attached.

Lather, rinse, repeat. Below, the releasing of Comsats 3 and 4, and a final picture of a comsat on station, 1000 km over Laythe's equator. You can see the central stack of docking ports/reaction wheel units shrinking after each refurbishment.

After refurbishing the four equatorial comsats, the RCS was down to 55%. The liquid fuel and oxidizer levels in the main X200-32 tank was just below 13%...but the two FL-T400 tanks on the nuclear engine nacelles are full, which is enough fuel to return the Tug to Kerbin for re-use.

The eight replacement comsats around the centra Comsat Bus core can be used later to replace the disabled comsats around Vall, Tylo, Bop, and/or Pol (as needed by future missions). The comsats orbiting those other moons were NOT equipped with docking ports, so they could not be refurbished like the Laythe comsats.

Two of the replacement comsats were deployed for placement into polar orbits around Laythe (since Laythe is where most of the exploration traffic is located). The two comsats were separated and their high gain and omni antennas and solar panels were deployed.

Shifting the orbital planes of these two comsats 90 degrees took most of the fuel they contained, but both ended up in polar orbits with their planes oriented about 90 degrees apart.

The final Laythe Comsta constellation is shown below.

Finally, the Tug was separated from the Comsat Bus. The Comsat Bus has a full X200-800 tank and four Rockomax 24-77 engines, which makes it capable of reaching any other Joolian moon (or multiple moons with careful planning). The Comsat Bus (which also functions as a comsat) will remain in Laythe orbit for now.

So... Back to my Eve and Duna missions (write-ups coming Real Soon Now).

Edited March 18, 2015 by Brotoro

[Dodgey]

Yay another episode, so are you planning on giving the Long Term Laythe Mission an actual ending?

[Brotoro]

I'm hoping I'll be able to set up exploitation of indigenous resources on Laythe (since that was part of the original mission plan) before I'm done.

[DMSP]

Cool work on the ComSats. My Laythe Base has had plenty of care recently but I only have one ComSat! I'll send my own "ComSat Bus" over to Laythe once I can get my CPU to work. Another thing on the list...

Also, If I build some light "Student Designed Experiments", would you bring some to Laythe or Duna?

[Scotius]

Space maintenance missions are always fun Especially when they are manned, and give excellent opportunities to role-play a bit with Engineers.

[Valley]

After reading all your mission reports I realize, besides using Mech Jeb, I may wish to start using Kerbal Alarm Clock if I wish to start going to the other planets.

[Scotius]

KAC is very useful when you are juggling multiple missions at once. But even when you are flying one mission, it can save you from time-warping past the maneuver node, peri\apoapsis or inclination node. So yeah, go get it

[aeroeng14]

I've lurked here long enough and I want to congratulate you Brotoro on a fantastic mission report series. I've been following Long-term Laythe since episode 1 right after I bought KSP myself and its served as an inspiration for a bunch of mission ideas and my own personal play style. This series I think is one of the best examples of how KSP can become something more than just a game about rocket science. I also want to say I'm a big fan of the science-y tidbits and references you sneak into all of your episodes and multiple series. None of these go unnoticed by a real-life rocket engineer with an astrophysics minor. Keep up the great work, and I'll always keep reading!

[macdjord]

By the way, in case anyone missed it, Brotoro recently posted an update to Exiting Eve.

[Commander Jebidiah]

Hey brotoro i saw your shift mistake care to explain it?

Also have you ever lost a kerbal

Edited March 18, 2015 by Commander Jebidiah

[Brotoro]

Hey brotoro i saw your shift mistake care to explain it?

Also have you ever lost a kerbal

Shift mistake? I can try to explain if you can explain what you're asking about.

On a very early mission, I sent Jeb, Bob, and Bill to Jool, and I didn't think they had enough fuel to return (I wonder now whether or not they did, if I was clever with orbital dynamics). So, they attempted landings on Jool, and were all lost. Mysteriously, they all showed up again later at the KSC. They claimed that they had enough fuel to return after all, and that they never tried landing on Jool. Others think maybe the mission was a hoax shot in a film studio...but we aren't allowed to discuss hoaxes on the KSP forums, so that's all I'll say.

I also use Jeb during very dangerous test flights of vehicles. Again, because of his mysterious ability to return after a seemingly deadly crash.

I've also had several other kerbals killed by game bugs...but I revert using F9 in those cases. For example, terrain glitch explosions vaporized Thompbles and Kurt many many times when they were exploring the surface of Pol. But I didn't hold that against them. And Ludger and Bobgan have crashed several times recently when they were bringing the Passenger Pigeon in for a landing from the east at KSC...when a mysterious "collision with the VAB" sheared wings off of their plane on final approach (they were not near the VAB). But I didn't hold that against them. Reloading the game cleared that collision mesh bug and they could land safely.

Back when I first tried to make aircraft in KSC, I smeared MANY kerbals across the landscape (mostly Jeb, now that I think about it)...but those were all reverted.

Adn certainly back during my first Mun landing attempts (in the old demo and in version 0.17), I crashed a lot of kerbals on the Mun.

But recently, I learn to do dangerous things (such as landing on Tylo) by practicing during "engineering simulations" before attempting the Real Thing in the game.

Edited March 18, 2015 by Brotoro

[Commander Jebidiah]

Your plane shift, or should i say plane sh**

Also thanks for telling me your deatcount. You are by far my favourite KSP story teller.

[Brotoro]

Which plane shift?

[Commander Jebidiah]

Part 44 in the mission pages here it is represented by ....

[Deddly]

Commander Jebediah, are you refering to the part where it says:

"the Standard Nuclear Tug carrying the comsat payload performs a plane .... burn, which happened to be very close to Jool's sphere of influence"?

If I understand you correctly, you think that the "...." is a miss-spelled "shift" that the forum has edited because it would have been a swear word. Is that what you are referring to?

[Commander Jebidiah]

Yes but in hos mission pages website it says sh*t

[Brotoro]

Ah! A typo in the third body paragraph. OK, I have fixed that. Thanks.

I guess I just did a shifty job proofreading.

But I appreciate it when people point out the typos so that I can fix them. Have a kerbal snack.

[Commander Jebidiah]

Jeb approves of that snak

[Rath]

Squad would probably have an issue with that.

Squad likes publicity

[Rath]

This thread is what made me get a forum account.

[FlyingPete]

What is to become of the Laythe mission now the 1.0 wave has struck? Do the planes still fly?

[Brotoro]

What is to become of the Laythe mission now the 1.0 wave has struck? Do the planes still fly?

I haven't tested the Laythe ships specifically yet. The BirdDog can still fly at KSC, but it's not balanced well (needs to have its CoM and CoL positions tweaked). Also, the severe hammering the Basic Jet engine received means that it won't be able to go as high or fast, and the higher fuel consumption rate will reduce its range. Also, I worry about how well it can drive around on the ground as a rover now because solar cells now obey 1/r², so power for the wheels will be much more limited out in the Jool system.

I wouldn't expect the original Laythe SSTO (based on jet engines) to be able to make orbit...but the RASSTO version might because it's built around RAPIERs. The little STUBBY SSTO rocket (also jet power) will be useless in reaching orbit as well. I expect the LadyHawk spaceplane (Turbojet) won't stand a chance to reach orbit, and the Raptor RAPIER version of the spaceplane is probably too draggy to get through the sound barrier. I read a post that said that scoop intakes no longer work as flotation devices...in which case anybody flying the Mallard will be in for a rude shock if he tries to land on water. Also, the Turbojet Mallard isn't going to be accidentally going into orbit anymore. (What are people able to do for seaplanes in KSP 1.0 with no decent flotation devices, accidental or otherwise?)

All the Standard Nuclear Tugs will suffer from all the problems outlined in Developing Duna 6.5.

Plus, Squad failed to fix the bug that causes the Mac version of KSP to crash after I play for a while (so much for the hoped-for 1.0 massive bug stomp), so it's frustrating to try to get anything done.

Edited May 12, 2015 by Brotoro