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

[Scotius]

@tuckjohn

When I saw your post, I realized something. Kurt Kerman's call name is Jaymack, and if you put Kurt with Jaymack, you get....

Kurtjaymack, or rather, kurtjmac!

Am i the first to notice this?

I'm Cobalt60, and I approve this message.

Check the map of Laythe with islands named by Brotoro's brave explorers. Many features are named after famous youtubers. Map is buried somewhere in the topic

[TimMartland]

Check the map of Laythe with islands named by Brotoro's brave explorers. Many features are named after famous youtubers. Map is buried somewhere in the topic

Yeah, like the island chain being named 'Hellou-Its-Scott-Manley-Here' or something like that.

[Brotoro]

Long-term Laythe - Part 25

Further Flashback

In Part 24 there was a flashback to the launchings of the R.A.P.I.E.R. powered spaceplane, the R.A.P.I.E.R. powered SSTO rocket, and the Airdale plane toward Laythe. Before we get to those payloads arriving at Jool, I'll mention the single ship that was sent out in the next transfer window that came up after those three payloads were sent (transfer windows from Kerbin to Jool occur about every 115 days).

Below we see the Laythe ShoreLab being launched on a Reusable Rocket. The ShoreLab is a jet-hopper/floating-laboratory designed to study the sea bottoms offshore from Dansen Island. Unlike Kerbin, where you can see someinteresting things through the water, the surface of Laythe's seas are not transparent (at least not with the video settings I use), but this ship will allow our explorers to peek beneath the surface (but not actually navigate around under the sea). This is also the first ship I've built using the cupola module, which will serve here as our glass-bottom boat.

To push the ShoreLab to Laythe, the boys at KSC decided to use Laythe Tug 3, which had returned earlier from Laythe and was sitting in Kerbin orbit. It only had standard docking ports, but this was a relatively light payload. Below is the Tug3 Refurbisher mission being launched on a Reusable Rocket (which can lift that payload into orbit without requiring any of the payload's fuel, and leave enough fuel in the sustainer that it can return to KSC). The rear tank will be docked to the bottom of the Tug, and then propellants and monopropellant from the top tank will be transferred to the main tank of the Tug. The top part of the Refurbisher will need to retain less than 15 units of fuel to deorbit and be recovered via parachute at KSC.

Once Tug 3 was refurbished, it was docked to the ShoreLab and was ready to be sent off to Jool. Just this one ship for this transfer window...and not even a double-Tug-train.

Tug 3 with the ShoreLab was sent off with a standard two-burn escape maneuver. The rear tank was expended during the escape burn, and dropped off as the ship left the Kerbin system. The ascending node occurred out beyond the orbit of Dres and took about 78 m/s of delta-V. We'll see the arrival of the ShoreLab at Laythe in a future episode (when the main game file gets to Year 26 Day 89).

Tug Treatments

For Laythe Tugs 4, 6, 7, and 8 that were waiting in Kerbin orbit, I decided just to land them near the KSC so that they could receive some minor improvements (adding Senior docking ports, and removing some unneeded parts). The following pictures show the recovery sequence with pictures of the various Tugs. First, Tug 4 does its retro burn. These Tugs all had enough fuel to target them in to KSC (in one case, just barely). Tug 4 will only need refitting with Senior docking ports.

Below, reentry is demonstrated by Tug 6. These later-model Tugs will need Senior docking ports added, and the removal of all those probe bodies that were included once upon a time for extra torque, but which are no longer needed because a single ASAS unit now provides plenty of torque.

Tug 7 demonstrates the two-stage main deployment of the parachutes. One pair was set to deploy fully at 600 meters, and the second set deployed fully at 500 meters. The resulting deployment shocks were gentle enough to keep the heavy nukes from snapping off.

Tug 8 landed close to Tug 7. All of the Tugs were landed to the west of the Research area of KSC.

Below, all four Tugs are down safely and the refurbishing can begin. Note that the nuclear engines will not be refurbished...the amount of fissile fuel you need to make the nuclear reactors work is much greater than the amount that would be used up in several trips to Jool and back (which each take less that 40 minutes of engine runtime), so the nukes are fine. I envision an unmanned rover/crane coming out to the Tugs to clamp some radiation shields around the nuclear engines (which are radioactively 'hot' because they have been used) to make them safe to handle by the refurb crews in the VAB.

Here's one of the refurbished Tugs as it would appear on top of a Reusable Rocket to be returned to orbit for continued use. Shortly before launch, the radiation shields will be jettisoned (see the animated GIF below). There are a couple girders on the side boosters to bounce the shields off to the sides. This leaves behind the minimal shielding of the engine fairings, and those will be jettisoned when the nuclear engines are ignited at high altitude.

Those Tugs will be used to send more payloads out to Jool later.

Train Traffic

Now we get back to the three trains (double-Tugs with double-payloads, one of which is just extra fuel) that are arriving at the Jool system. Tain #1 did not reach the ascending node of its transfer orbit until it was within Jool's sphere of influence, but Train #3 and Train #2 required plane-shift maneuvers enroute. Because these occurred close to Jool, they only required about 51 m/s of delta-V. This expended the propellants in the rearmost tanks of Train #2, and they were dropped after the burn.

I decided to take the easy route and target all three trains straight to Laythe (rather than do an aerocapture at Jool first). Train #3 and #2 were both targeted very close to Jool back when they left Kerbin, so those orbits were just tweaked a bit until they got Laythe encounters, as seen below, with Train #3 swinging past Jool to a farside encounter and Train #2 encountering Laythe on the way in. Both of these trajectories resulted in intercept velocities of around 5,000 meters per second, leading to hot aerocaptures.

For comparison, Train #1 was targeted (after entering Jool's SOI) to approach Laythe close to tangentially to its orbit. This resulted in an intercept velocity of only 2973 m/s, much less than the other two trains. Changing the radial component of the targeting burn moves the trajectory closer or further from Jool to get the correct intercept with Laythe, and changing the prograde/retrograde component allows you to adjust where Laythe will be in its orbit when the ship arrives (and adjusting the normal component allows you to determine the inclination of the resulting Laythe orbit).

Below, Train #1 came in tangentially and experienced only a few G's and rather anemic flames during aerocapture. Very nice!

After a burn to correct orbital inclination (which expended the rearmost tanks, which were then dropped), and a burn to adjust periapsis for an additional aerobraking pass, and a burn to circularize, the R.A.P.I.E.R. spaceplane and NAMOR 21 payload were safely in low equatorial orbit with nearly three full big tanks of fuel in the double-Tugs.

Below, Train #2 with the R.A.P.I.E.R. SSTO rocket arrived for a flaming hot aerocapture, experiencing up to 8.5 G's of deceleration. After the usual maneuvers, it was also safely in low orbit.

Train #3 swung around close to Jool for a farside encounter with Laythe that was also of the hot 8.5 G variety.

After a plane shift and some orbital tweaks, Train #3 was also in a low equatorial orbit with three nearly-full big tanks in the Tugs (it retained its rearmost tanks, now empty). Such fine deliveries...I should work for FedEx.

Payload Presents

Time to deliver the toys! First down, the R.A.P.I.E.R. spaceplane.

Aldner: "OK, Little Buddy, I'm going to let you fly the spaceplane down under remote control because I'll be the one piloting it for its first flight back to orbit."

Nelemy: "Cool, Dude! Have you chosen a name for it yet?"

Aldner: "It will be named Raptor."

Nelemy: "Um... Rapier Aerospace Plane To Orbit...um...'Round?"

Aldner: "No. Just Raptor."

Nelemy: "Cool."

Aldner: "Let me undock that Saddlebag Deorbiter...we won't be using that."

Nelemy: "Don't we want to land with maximum fuel?"

Aldner: "Maybe later...but I want to do a direct comparison with the performance of the Ladyhawk flight I made, and we didn't use a Deorbiter bringing it down...so we'll let Raptor use its own fuel to deorbit. OK...the Saddlebags are off of the Raptor's docking port...decouple the Raptor from the NAMOR's docking port, and I'll re-dock the Saddlebag Deorbiter to the NAMOR."

Note that the structural plate, girder, and decoupler that held the Raptor to the ship was decoupled along with the Raptor (to free up the top port of the NAMOR), but unlike when the Ladyhawk was deorbited (carrying this junk with it to be jettisoned after retro burn), the Raptor will need to separate the junk before it can use its R.A.P.I.E.R. engine...so that junk will remain in orbit.

Below, Nelemy fired the R.A.P.I.E.R. engine (in closed cycle mode) to deorbit the Raptor (with the Tugs visible in the upper-left).

Rather than waste fuel changing the inclination in orbit, Nelemy used the cross-range capability of the Raptor during entry and in the lower atmosphere to move the ship one degree north to Fido Bay.

Nelemy: "Annnnnd.....touchdown, Dude!"

Aldner: "See how close you can park it to the Ladyhawk, pointing southeast."

Nelemy: "Sure thing. Huh. This new nose wheel steering doesn't seem to be working all that well."

Aldner: "Is it activated?"

Nelemy: "Yeah, Dude."

Aldner: "Ah...you can't steer it with the yaw control, you need to use the rover turn-controls."

Nelemy: "Oh. Whoa! Too sharp. OK, coming around now. Big wide arc. I can turn sharper if I use opposite roll to keep it from wanting to roll over."

Aldner: "You're going to overshoot."

Nelemy: "Close enough. Lined up perfectly. Wheels stop. Your ride is delivered, Dude!"

Next, Kurt brought down the R.A.P.I.E.R. SSTO rocket via remote control. All those glowing-hot R.A.P.I.E.R. engine nozzles look awesome after the retro-burn cutoff. He named it 'RASSTO' for "Rapier Accelerated Single Stage To Orbit," and it is properly pronounced as if Scooby-Doo was saying it.

Not much to control during entry, other than to decide when to pop out the reefed chutes. Two chutes mounted low on the main fuel tank are set to open fully at 600 meters, followed by the other six chutes mounted high on the Hitchhiker Module set to open fully at 500 meters.

With all of the parachutes fully open, the almost-fully-fueled RASSTO still descends at 9.4 m/s, which would damage the new landing gear. So Kurt cut in the engines again just before touchdown to reduce the speed to a few meters per second. This was done with the engines still in closed-cycle mode (rather than air-breathing mode) because it's easier that way (although doing it the trickier way in air-breathing mode would take less fuel...and might not be as difficult as trying to land on jet engines alone would be, because the parachutes have slowed the ship down so there is more time to react to the spool-up/spool-down lag time).

Below, the RASSTO is safely down about 630 meters from the original crew-transfer SSTO rocket. After landing, the RASSTO had a little under 91% of its liquid fuel left, and its oxidizer tanks were filled to a little over 84% of their capacity. The difference in those percentages is because the small side tanks were tweaked to hold less than 100% of their oxidizer capacity, because the ship will use more fuel than oxidizer during ascent because the R.A.P.I.E.R. engines will initially boost the ship in air-breathing mode. It will be interesting to see how well it does returning to orbit (but Kurt better remember to repack the chutes).

Last down, the 3-kerbal version of the BirdDog, which Thompbles brought down via remote control. Below, the retro burn (the Tug Train in the background still has a GasStation attached, which can be landed later).

Nelemy: "So what are you going to call our new BirdDog Airliner? You should call it AirDoggie, Dude."

Thompbles: "I'm naming it Airedale. On course after retro burn. Decoupling the retro pack now."

The Airedale came through the entry flames on automatic, then Thompbles jettisoned the rover-wheel heat shields.

The Airedale was coming in to the Laythe Base area at over 8,500 meters...

Nelemy: "Dude, you're coming in high!"

Aldner: "You'll need to pass over and circle back around."

Thompbles: "Not necessarily..."

Instead, Thompbles rolled the Airedale upside down, then "pulled up" to put it into a dive straight down for about 4,000 meters. Then he rolled it back 180 degrees around and pulled up, leveling the plane off at less than 1,000 meters altitude...which put the plane right in position for a standard landing approach.

Nelemy: "Dude! Airliners don't fly like that."

Aldner: "With a maneuver like that, I expected to see you dropping flares and chaff."

Thompbles: "I couldn't find the buttons for flares and chaff."

Nelemy: "Dude, you're a lot braver than I am trusting that you could do that pull-up without the plane flipping out in pitch!"

Thompbles: "You should try this out in the simulator. This bird has three pods worth of torque authority...it can fly at much higher angles of attack than the BirdDogs without flipping out."

Aldner: "Um...you're going to land a couple kilometers long compared to what we usually do."

Thompbles: "I know. That's because I'm going to bring it over here to us at Base 2 during the rollout."

Thompbles drove the Airedale over to Base 2 and parked it next to Aldner's BirdDog 1. See the image below to compare the two planes. As mentioned before, the Airedale uses the exact same basic structure as the BirdDog (same placement of fuselage, wings, gear, docking port, etc.) so that it will be able to use the same GasStations.

Next episode: Playing with the new toys.

Edited January 23, 2014 by Brotoro

[macdjord]

You know, I'm sure there's a 'flares and chaff' mod somewhere~

[Logan.Darklighter]

Nice. Thombles is an old pro and a cool cat.

[Scotius]

Nice. Thombles is an old pro and a cool cat.

It's always those quiet and unassuming ones... Anyway, was that Kerbal Christmas on Laythe? So many cool toys to play with - guys must be extatic.

[Commissioner Tadpole]

If Thompbles did that daring manuever while landing, I can't wait to see him fly.

[The Error]

Wow. Thompbles is surprisingly badS.

[borisperrons]

My god, that's simply brilliant!!! I read all this thread in a week and wow, what a writing!!!

Kudos to you, Brotoro!!!

[JumpsterG]

Thank you, Brotoro, for another fine example of the arts of engineering, mission planning, and mission execution.

(And for taking a LOT of extra time to share it with us in a meaningful, easy-to-follow format)

Edited January 23, 2014 by JumpsterG
I am my own grammar ****

[meve12]

Why did I imagine the radiation shields making the sounds of tin cans as they drop?

[Brotoro]

I envision the shields as being mainly borated polyethylene surrounded by steel, so I imagined more of a "thunk" noise myself.

[Tw1]

Careful with that cupola in the water! I ended up using a mk 1 cockpit in my glass bottom boat, as it the cupola was just too fragile. But then, that vessel was designed to travel through Eve's ocean, not hop about above it.

[iBeej]

Impressive work my friend. All of it. Your technical prowess, your articulate story-telling, and your ability to share it with the masses.

If there is one thing I can assure you of...

You will either INSPIRE many of us, or you will make them quit.

Absolutely stellar performance. Loved every minute of it.

[Brotoro]

Careful with that cupola in the water! I ended up using a mk 1 cockpit in my glass bottom boat, as it the cupola was just too fragile. But then, that vessel was designed to travel through Eve's ocean, not hop about above it.

Jeb has tested it offshore at the KSC...seems to hold up.

[DaserTheGamer]

Coole brotoro

[meve12]

I envision the shields as being mainly borated polyethylene surrounded by steel, so I imagined more of a "thunk" noise myself.

Or maybe the sounds of empty oil cans.

[AppleDavidJeans]

Brotoro, I'd like to know the design process that you went through in building the Ladyhawk. I'm building an SSTO spaceplane derived from yours. Thanks.

[Brotoro]

Brotoro, I'd like to know the design process that you went through in building the Ladyhawk. I'm building an SSTO spaceplane derived from yours. Thanks.

Ladyhawk is based on the BirdDog as a starting point, because I've flown the BirdDog around a LOT, so I was very familiar with its aerodynamics (such as they are in KSP). And the design of the BirdDog came from wanting:

a) a relatively small plane so it would be easy for the Tug to move it to Laythe

a range of at least halfway around Laythe, so two tanks of fuel

c) a compact design that could work well as a rover, hence the shorter jet engine rather than the more efficient turbojet you'd want if you were more interested in FLYING

d) cockpit chosen for high survivability and good IVA views

For the Ladyhawk, I figured I'd want extra fuel/oxidizer to reach orbit and have enough to maneuver around up there. I did some early tests with the BirdDog where I gave it FOUR tanks of fuel so that it could more than circumnavigate Laythe, but that prototype was so heavy that I could not land it reliably (almost always crashed it). So when I added more fuel/oxidizer to the Ladyhawk, I used smaller side tanks and made it a biplane for greater lift.

Unlike SSTOs around Kerbin (where your fuel is on the ground), the Ladyhawk's fuel supply is in orbit, so it has to be able to land with nearly-full tanks, so adding the extra wing area was important. If you were going to be flying from a place where your fuel source was on the ground, then the extra wings would not be needed.

I used the single-kerbal lander can for the additional passenger module for the Ladyhawk because it was lightweight and had a nice window.

I used four Rockomax 24-7S engines, firing down between the wings, but probably two would be sufficient. But the first SSTO spaceplane I got into orbit around Kerbin was a variant of the BirdDog and it used four Rockomax 24-77 engines, so I knew four would work.

I put the Ladyhawk's docking port a little forward of the center of mass so that I could put the RCS quads at the CoM…but for the Raptor I moved the docking port back to the CoM so that it would be easier to push the plane around in orbit using a Tug if needed.

Whereas the BirdDog has lots of surface-mount solar panels and battery packs for roving, I gave the Ladyhawk an RTG for simplicity (it's underneath behind the lander can).

I gave the Ladyhawk just one small RCS tank because I've been using a lot less RCS fuel during docking since the control systems have been refined in the recent versions of KSP. Also, I have Tugs in orbit that could rescue/refuel the plane if it ran out of RCS fuel.

Because the Ladyhawk had no rover wheels like the BirdDog, and because I didn't want to use fuel moving it around on the surface, I also added the small docking port on the front underside so that I could drag it around with the little service rover.

And that's where the Ladyhawk came from.

Edited January 27, 2014 by Brotoro

[TimMartland]

Aww. I want to see how the water lab does. That looks cool.

[USKnight]

Dear Brotoro,

I'm a big fan of Cashen's MASEC AAR and the way he presented his story and program. One of his influences was your series of AARs, so it was natural that I would come here to see it for myself. I have to say that you tell a heck of a story and I really enjoyed your adventures with the Mark Twain and Lewis and Clark landers. Like Cashen, your play style and presentation influence my desire make my own stories and chronicle the adventures of my own Space Program.

While that day will likely never come, I wanted to say thank you for sharing these stories and breathing life to Kerbal Space Program. You have a devoted fan who enjoyed reading your earliest AARs to this latest fantastic creation.

[Brotoro]

Long-term Laythe - Part 26

Rapier Results

Raptor Flight 1

This episode is all about engineering tests of the new R.A.P.I.E.R. SSTO spaceplane and SSTO rocket.

Aldner recently flew the Ladyhawk turbojet-powered spaceplane to Laythe orbit with 2,567 m/s of delta-V remaining. Now we want to see how well would the R.A.P.I.E.R.-powered Raptor performs (it is essentially the same plane with a different engine). Aldner's partner for the Raptor tests was Nelemy, seen below climbing aboard the passenger cabin of the Raptor.

Aldner: "Raptor to Fearless Leader. We are ready to roll."

Thompbles: "OK, Aldner. Take lots of data for the boys back at KSC."

Aldner: "Roger. Are you ready back there, Nelemy?"

Nelemy: "Dude, the snack cabinet empty!"

Aldner: "Yes, I know. And if you do a good job as flight engineer, I'll tell you where the snacks are hidden once we reach orbit. Brakes off. Engine in air-breathing mode. Manual mode-switching on. Firing up the R.A.P.I.E.R. now."

Aldner took off toward the southeast to fly down to the equator.

Nelemy: "OK, Dude, you're half an arc minute from the equator. Point it straight east."

Aldner: "Thanks. Starting the serious climb now. I know this new engine is supposed to have the same thrust as the turbojet, but the plane feels more sluggish."

Nelemy: "Because of the higher mass?"

Aldner: "It's only an extra half ton. Unless you brought a lot more snacks on board that I don't know about. Maybe it's my imagination. I'll take her up to 25 thousand and level off."

Nelemy: "22 thousand. Intake air 0.02. Speed 1250. 23 thou...flame out!"

Aldner: "Huh. The turbojet was still going strong here. Throttling back."

Nelemy: "Engine restarted."

Aldner dropped back to 21,000 meters, then bobbed up to 27,000, then back down to 24,000. He finally found a cruising condition at around 27,000 at 1/3 throttle.

Aldner: "This engine certainly drinks fuel faster than the turbojet, and it doesn't seem to want to cruise along at as high an altitude. I had the turbo sipping fuel at over 30 klicks and still accelerating...but this R.A.P.I.E.R. just seems anemic."

Nelemy: "27 thousand again. Speed 17 hundred. Intake air holding at 0.01, Dude."

Aldner: "I'll just keep cruising along here and wait for the magic moment. Let me know when the predicted periapsis goes positive."

Eventually Aldner dropped back down a little to 26,000 where he could run at half throttle.

Nelemy: "Dude, we're 25 minutes into the flight. Speed 1830."

Aldner: "Yeah, this is taking a lot longer to get up to speed."

Nelemy: "26 minutes. We've flown a long way around Laythe, Dude. Ah! Periapsis is positive!"

(The display in KSP rotates 90 degrees once the periapsis exceeds 18 kilometers)

Aldner: "OK! Now let's see if the apoapsis grows like crazy."

Nelemy: "Apo rising, but slowly."

Aldner: "Yeah. Son, I am disappoint. It's not going crazy like last time."

Nelemy: "28 minutes. Apo at 30 klicks. Flameout!"

Aldner: "Damn. Throttling down. Which is making the speed increase even slower. OK, I think a half hour of this is enough. Get ready for switch to closed-cycle mode."

Nelemy: "Speed 19 hundred. Apo 40 klicks."

Aldner: "Rocket mode on!"

After having flown 3/4 of the way around Laythe, Aldner switched the R.A.P.I.E.R. to closed-cycle mode and boosted the apoapsis to 256 kilometers, then cut the engine. Aerodynamic drag decayed theapoapsis down to 142 kilometers before the Raptor rose out of the atmosphere.

Aldner: "Raptor to Base. Come in, Cap'n T. We're passing overhead."

Thompbles: "I read you, Aldner. How's it going?"

Aldner: "Well, we are in space, but not orbit yet. Still 9 minutes to apoapsis."

Thompbles: "Really? What have you guys been doing."

Aldner: "I've been driving along like a little old lady. But fuel is OK. We'll make orbit fine."

Nelemy: "So where are the snacks, Dude?"

Aldner: "We aren't in orbit yet, Little Buddy."

As the Raptor was approaching Manley Island, Aldner performed the burn at apoapsis that put the Raptor into a stable orbit of 80 by 142 kilometers. This left the ship with 952 m/s of delta-V (according to MechJeb's data readouts). That's more than enough for lots of orbital maneuvers, but somewhat disappointing after the previous Ladyhawk flight. The Raptor's orbit was inclined about 0.6 degrees, so Aldner did a burn at the ascending node to align the Raptor's orbit to the equatorial orbit of Laythe Space Station. This left the ship with 935 m/s delta-V...at which point he told Nelemy that the snacks were hidden in the survival gear compartment.

Below, the Raptor does some orbital maneuvers to rendezvous with Laythe Space Station. The R.A.P.I.E.R. engine has more thrust than the four Rockomax 48-7S rocket engines on the Ladyhawk, and even has a higher vacuum specific impulse, so the orbital maneuvers went well.

The Raptor docked with Laythe Station and refueled. Remember to top off the RCS fuel in your cockpits, capsules, and lander cans, kiddies!

As with the Ladyhawk, the Raptor did a retro burn directly retrograde to bring it down over the equator, and Aldner banked the plane to the left through reentry and afterwards to move the one degree north to Fido Bay. The Raptor used a little less than 8.9% of its oxidizer for the retro burn.

Aldner: "We're coming in high."

Nelemy: "You could do a 'Thompbles' and drop us quickly, Dude."

Aldner: "Let's not."

Aldner brought the Raptor around in a wide turn east of the Base 1 area and was even still banked pretty hard down at 130 meters. Eventually he leveled out and landed toward the southwest. The landing was done without using the engine (other than for deorbiting).

Below, after a perfect rollout, Aldner brought the Raptor to a stop alongside the Ladyhawk pointing southeast, ready for another flight. It wasn't even necessary to get the Runabout rover to reposition the plane. The plane can make pretty sharp turns during the rollout as long as you remember to use the roll controls to counter the tendency of the plane to tip to the side as you use the remapped rover-steering keys to turn.

After the flight, Aldner and Nelemy studied the flight data plot to consider how they could get better results on the second test flight.

Nelemy: "Dude, you could have kept the altitude curve smoother at the start."

Aldner: "True. The R.A.P.I.E.R. flamed out sooner than I expected. Keep that in mind and pitch down sooner on the next flight. My main concern is that cruising along at 26 to 27 thousand at a third-to-half throttle just didn't seem to work well. It took way too long to build up speed. And I didn't get the feeling that trying it higher at even lower throttle would work well like it did for the turbojet. Maybe it would work better at higher altitude...or maybe we may need to stay lower and run at full throttle."

Nelemy: "I like full throttle! Pedal to the metal, Dude!"

Aldner: "Then you may want to start your cruise at 22 thousand, and climb very slowly as the speed increases so the engine can tolerate full throttle all the way. Certainly stay below 25 thousand until the end of the cruise."

Nelemy: "Cool."

Aldner: "The other problem I had was that I burned too much liquid fuel, so I had excess oxidizer when we reached orbit. To have more delta-V in orbit, you should try to have matching amounts of fuel and oxidizer when you switch over to rocket mode. Since the Raptor currently has 402 units of oxidizer, you should have at least 329 units of fuel at switchover."

Nelemy: "Dude! Sounds like a plan! Can we take some Goo?"

Aldner: "No."

 

Raptor Flight 2

Raptor flight, Take 2. Nelemy in the cockpit, Aldner riding in the lander can. Pedal to the metal.

With his more agressive climb, Nelemy was over 11 kilometers up by the time he got lined up on the equator.

Nelemy: "18 thousand, pitching down, Dude!"

Aldner: "Pitch down more."

Nelemy: "Argh, Dude. It's slow to respond."

Aldner: "23 thousand, speed 1550. Flameout."

Nelemy: "No!"

Aldner: "Decrease throttle."

Nelemy decreased the throttle to two-thirds and fought the Raptor back down slowly. As the speed increased, he was able to slowly increase the throttle and got back to full-throttle cruise at just over 23 thousand. Oddly, the intake air was reading zero this whole while (but it had been reading 0.01 for Aldner higher up).

Nelemy: "OK! Pedal to the metal again!"

Aldner: "Speed 1800. Doing great, Nelemy. You can slowly rise as your speed increases. 11 minute mark."

Aldner: "12 minutes. Speed 1860. Periapsis over 18 km!" (the display rotated)

Nelemy: "Dude, it keeps trying to pull up on me."

Aldner: "That's the ground dropping away from under you at this speed. Your apoapsis is rising well, 32 thousand. Stay on target."

(As Nelemy allowed the pitch to increase, the upward thrust dropped the periapsis back below 18 kilometers and the KSP display rotated back to horizontal)

Nelemy: "Argh! Flameout! Throttle down a bit. Another flameout! Maybe I should go to rocket mode."

Aldner: "Your apoapsis is still rising. Stay on target."

Nelemy: "My speed is dropping."

Aldner: "Stay on target."

Nelemy: "Throttle down to one-third, Dude! I wanna go!"

Aldner: "OK, apo increase is slowing down. Kick it."

Fourteen minutes into the flight, Nelemy switched over to closed-cycle mode and kicked the apogee up to 136 kilometers with less than 10 seconds of rocket thrust.

By the time the Raptor had risen to 42 kilometers, the apoapsis had decayed back down to 75 kilometers, and Nelemy used another short burst of rocket power to raise it...then another short burst later to raise it to what ended up as a final value of 123.5 kilometers when they reached space.

A burn at apoapsis placed the Raptor in an 89 by 123 km orbit, inclined 0.3 degrees, with 1467 m/s of delta-V left onboard. So that method was superior to the first flight, and took a lot less time to do. But the second Ladyhawk flight still had better results.

Rather than go to Laythe Space Station, Nelemy rendezvoused with the Laythe Train that had brought the Raptor to Laythe. The train (which still had NAMOR 21 attached) had plenty of fuel to refuel the Raptor, and it also had the Saddlebag Deorbiter attached. This required careful alignment when docking.

Once they were docked, Nelemy and Aldner refueled the Raptor.

Below, the Raptor separated from the Train along with the Saddlebag Deorbiter so they could test the deorbiting maneuver using the Saddlebags. The purpose of the Saddlebag Deorbiter is to deorbit the spaceplane without the plane having to use any of its own fuel so it could land with full tanks. (I originally slapped the Deorbiter together and sent it along just in case the spaceplanes turned out to be very marginal in getting to orbit...but both the Ladyhawk and Raptor have proven that they don't need this extra help...but I wanted to try it out anyway.)

To deorbit the plane using the Saddlebag Deorbiter, the docking port on top of the Deorbiter is set as the "Control From" point. Then the four 24-77 engines on the Deorbiter do the retro burn. The balance was not perfect, so this was a bit tricky, but it worked out OK.

After the retro burn put the ship on target for a landing near Fido Bay, Nelemy rotated the plane so that the Deorbiter was aimed at right angles to the plane's trajectory, then Aldner remotely controlled the Deorbiter to separate, then pointed it prograde, then fired its engines again to place the Deorbiter back into a stable orbit. He overshot a circular orbit by a bit, but he was working fast. The tanks on the Deorbiter were still over half full after the retro burn and re-orbit burn.

(The Raptor ended up over 2.5 kilometers from the Deorbiter by the end of the re-orbit burn, so a quick trip to Map View was needed to switch back to the Raptor.)

Nelemy had lots of time to orient the Raptor for reentry, and then did a typical reentry and cross-range maneuver. They were again coming in too high, so he did a wide arc around the Base 1 area and came back toward the west to land.

Nelemy: "Down! Nose gear steering enabled. I bet I can get it closer to the Ladyhawk than you did, Dude."

Aldner: "If you do, snacks are on me tonight."

Nelemy: "OK...OK...wheels stop!"

Aldner: "Excellent job, Little Buddy! I owe you some snacks."

Meanwhile, back in orbit, the Saddlebag Deorbiter needed to be returned to the Train for refueling in case they ever decided to use it again. As usual, this thankless job went to Thompbles. He raised the periapsis to put the Deorbiter into a slightly higher, slower orbit to await the train to catch up with it. But, after several orbits, when the time came drop the Deorbiter back down to rendezvous...there was no response from the vehicle. Ah. Well, lookie here. It sems that I forgot to put any solar panels on the thing, so the probe core (between the two docking ports) had used up all its electric charge while waiting for the rendezvous. Now who looks silly?

The plot of the second Raptor flight data is shown below (using the same horizontal scale as Flight 1). And immediately below it, I have placed the plot from Flight 1 for easier comparison.

 

RASSTO Rocket

For our more impatient customers, we offer the RASSTO Rocket for their Laythe orbital travel needs. With a crew capacity of four, it uses somewhat more fuel than two flights of the two-kerbal SSTO spaceplanes, but it can be a good choice for Laythians with an on-to-go lifestyle who want to do without all that tedious mucking about in the stratosphere.

Kurt and Nelemy were chosen to test the R.A.P.I.E.R.-powered SSTO transport rocket. They first had to make a couple trips over and back from Base 2 to empty all of the cases of supplies that were packed into the crew compartment when the RASSTO was sent to Laythe from Kerbin. Below, Kurt repacked the eight parachutes while Nelemy had a last snack at the Fido rover.

In fact, I spent quite a lot of time messing with the parachutes. Because of a bug in KSP, repacked parachutes won't deploy using the staging sequence -- you can mess around resetting the staging sequence, moving the repacked chutes here or there, but the new arrangement just won't "take" and disappears when you switch away from the ship. You CAN deploy the chutes using action group keys -- but another bug causes the chutes to deploy instantly fully open, ripping your ship apart (although the parachutes rather embarrassingly notice that they shouldn't have opened fully, so they quickly switch to reefed appearance before you can notice what's going on...not that this is any help for your mysteriously-ripped-apart ship). Luckily, this second bug CAN be avoided by either switching away from the ship to the Tracking Station, then switching back, or by doing a Quicksave followed by an F9. Either way allows the chutes to be deployed later safely by action group.

I ran into this bug back when I was testing the NAMOR prototypes back on Kerbin, and I thought that I had also found a combination of steps that allowed the repacked chutes to work in the staging sequence again, but I could not duplicate that behavior here. Happily, the RASSTO has action keys to deploy the chutes in multiple pairs (the 5 key deploys the two chutes on the main tank, the heaviest component of the structure; the 6 key deploys two chutes on the crew cabin; and the 7 key deploys the other four chutes on the crew cabin).

Now that we have tweakable parachute full-deployment altitudes, the need for staged deployment is obviated, and the chutes are simply set to open fully in stages between 600 and 500 meters, starting with the two chutes on the main fuel tank.

Kurt: "Ready, Nelemy?"

Nelemy: "Ready, Kurt-Dude!"

Kurt: "OK. All four engines are in air-breathing mode, manual mode-switching. Stability controls on. Throttling up to 100%."

Nelemy: "Pedal to the metal!"

(There was a wait as the engines spooled up)

Kurt: "Liftoff. Raise the legs. Pointing vertical."

Nelemy: "Landing legs up, Dude! Pedal to the metal!"

Kurt: "You can stop saying that."

The RASSTO can supposedly make orbit following a 'standard' rocket trajectory (starting a gravity turn at two atmospheric scale heights...8000 meters on Laythe), but it can do better with an earlier and more agressive turn so that the ship can pick up more horizontal velocity during the jet-engine phase of the flight.

Nelemy: "How soon do you have to start turnover?"

Kurt: "Hey, I don't know what I'm doing...I'll just play it by ear. Starting turn now."

Nelemy: "700 meters."

Kurt: "I'm going to turn to about 45 degrees."

Nelemy: "3600 meters...20 degree turn...6000 meters...30 degrees...12000 meters...35 degrees."

Kurt: "OK, I'm holding this angle. The prograde marker is drifting below 45 degrees."

Nelemy: "Dude, when are you going to switch engine modes?"

Kurt: "At the first sign of flameout. It will probably be between 20 and 21 klicks."

Nelemy: "We got up to 23 before flameout in the Raptor, Dude."

Kurt: "Yes, but my horizontal velocity is not as great as yours was."

At 17,000 meters, Kurt turned over more to center his heading on the prograde marker (at about 50 degrees from vertical) as he approached the switchover altitude.

Nelemy: "20 klicks, speed 660.....21 kli..."

Kurt: "Flameout. Switching modes!"

(Kurt pressed the big button labeled "1" that toggled all four engines to closed-cycle mode to continue on rocket power)

Nelemy: "A little jiggle there, but pretty smooth."

Kurt: "OK, turning more toward horizontal. Read me the predicted apoasis figures."

When the apoapsis exceeded 70 kilometers, Kurt cut off the engines.

Kurt: "And now we coast. Pointing to the horizon. Let me know when we get to 10 seconds from apo."

Nelemy: "Nice boost. I haven't even had time for a snack yet, Dude! Where are the snacks hidden?"

Kurt: "Hidden? Just stay in your seat."

At five minutes into the flight, ten seconds before apoapsis, Kurt fired up the engines again and put the RASSTO into a 69.8 by 72.7 kilometer orbit. The ship had 540 m/s of delta-V left...way more than needed for a rendezvous with Laythe Space Station. The RASSTO had a small excess of fuel over oxidizer.

The orbital inclination was 1.167 degrees, and this required a 38 m/s burn to shift it to match the equatorial orbit of the space station. Perhaps it would help to launch a little toward the south from Fido Bay and do a little dogleg toward the east when boosting in jet-power mode... but that would be a lot to keep track of during the relatively short boost time of the RASSTO.

Kurt made a standard rendezvous and docking with the Laythe Space Station.

Kurt: "Zero-G sure is fine. It's great to be back at the space station."

Nelemy: "Eh. We have more kinds of snacks down on the surface, Dude."

Kurt: "Why don't you go play outside."

When refueling the RASSTO, Kurt filled the four FL-T200 tanks with 91.52 units of oxidizer in each. This was a little more than the 88 units that each had been tweaked to hold initially when the ship was sent out to Laythe. This should result in a better fuel/oxidizer ratio after the RASSTO next flies to orbit.

Kurt and Nelemy spent a few days at the station to take some high-resolution images at various sunlight angles of several sites around Laythe where Hellou said there might be interesting geology (a term derived from the name of the ancient kerbal God of rock, dirt, and mountain vacation spots), based on her analysis of samples collected during the boys' earlier BirdDog explorations.

When it was time to return to Laythe Base, Kurt used the landing guidance computer to help him target the RASSTO back toward its liftoff location, and made a simple ballistic entry. The retro burn used about 12.6% of the ship's oxidizer.

At 5000 meters, the parachutes were deployed in reefed condition via action groups, and the landing legs were extended (with suspension active). At 600 meters the two chutes mounted on the main fuel tank deployed fully, followed by the rest of the chutes at 550 and 500 meters.

The RASSTO was descending at 9.6 m/s (too fast for the new landing legs to handle), so Kurt toggled the R.A.P.I.E.R. engines to air-breathing mode and fired them up at 100 meters, raising the throttle to one-third power and slowing the descent to 7 m/s for landing.

Our heros landed about 400 meters east of their takeoff site, so while Kurt repacked all the parachutes, Nelemy summoned the Fido rover over by remote control. Then the boys headed back to Base for a celebration dinner that couldn't be beat.

Next episode: Hmm...the Travels of Thompbles, I suppose.

[Patupi]

Way to go with testing Brotoro! Love the way you've managed all this was almost no mods (Mechjeb and docking cam... that's about it, right? Do you use editor extensions or anything?)

During that second flight I loved the scene with Nelemy:

Aldner: "Your apoapsis is still rising. Stay on target."

Nelemy: "My speed is dropping."

Aldner: "Stay on target."

Nelemy: "Throttle down to one-third, Dude! I wanna go!"

I kept expecting him to say 'Loosen up!'... that reminds me, I've been slacking on my AAR. Haven't had any misquoted movie references for AGES!

[Brotoro]

Mods? I current have these installed:

Kerbal Alarm Clock (for transfer windows and keeping track of multiple ship transfers)

Precise Node (improves the maneuver node interface)

Visual Enhancements: Clouds and City Lights (prettier planet views, although it makes it harder to spot surface features)

Romfarer's DockingCam (makes docking more fun)

SelectRoot (makes building things in the VAB easier…changes the root part of a ship)

MechJeb2 (targeting precise landings and aerocaptures would be a pain otherwise; and for pointing at nodes during long burns and other tedious stuff; and data displays)

Dishy's Bill9000 (to add MechJeb to ships)

I also still have Protractor and Kerbal Engineer installed because I have parts for those stuck on various ships, but I no longer use them (I use Kerbal alarm clock or online info instead of Protractor, and I use MechJeb's data displays instead of Engineer)

And I have HyperEdit for testing designs and for getting around game "bugs," such as having to reposition my old Bases and GasStations after the new landing leg update (with undeployed legs) caused them to fall over.

[Patupi]

Never tried Bill9000. Might give it a go. I tried Protractor a few times, but never really liked it. Just tend to stick with Mechjeb and just not use any actual autopiloting. About the only 'auto' feature I've used in that in ages was the Smart ASS.

(EDIT: I guess Mechjeb and the 'time to intercept' in Alarm Clock. That makes it a lot easier to gauge when to start setting up an IP transit.)

Edited January 29, 2014 by Patupi