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The Neptune Mission Files: A Laythe Exploration and Colonization Saga


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LUDLONG KERMAN'S MISSION LOG: Y34D155 - 2H15M

(NEPTUNE I)

While our space program still sucks at SSTOs, our reserve kerbalnauts are demanding we send people to Laythe. After all, if the Elegail rover is reporting an atmosphere similar to Kerbin's, then it would make a good place to settle. Though our engineers are still working on a feasible method to get people on and off Laythe's surface, Mission Control decided to at least start expanding our Laythe presence - starting with:

  1. A space station
    1. We have a permanent contract to dock to vessels around Laythe.
  2. Return a vessel from Laythe orbit to Kerbin
    1. At least we can get a manned orbital reconnaissance mission of the moon with full science points (e.g. crew and EVAs, goo, materials).
    2. Too bad it wasn't a landing mission.

 

rx9ubm3.jpg

  • The Elegail rover on Laythe.

 

While Mission Control is constructing Odin Station - which would look exactly like Hades Station in orbit of Eeloo - the current general plan for the descent vehicle is to land on the surface and rendezvous with a separate return craft upon ascent; that may also be the case if we send an SSTO (which also means we'll have to leave the plane). All future mission plans aside, the three of us - Nathan, Matster, and myself - are flying to Laythe to explore the planet from orbit. We're in the Neptune I, a modified interplanetary travel pod designed to carry less passengers (we need 3 people, not 7), more battery power, and more science.

FKFFQVM.jpg

 

In a couple of years, we'll be right in Jool's orbit. We'll then orbit Laythe and get some science and photographs before heading back home. If anyone has any ideas for a two-way surface mission craft (either a lander or SSTO), I'm open.

Edited by Mars-Bound Hokie
Expanding on the title a bit.
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Laythe SSTOs are actually easier than I expected. The need for lots of wing area is compensated for by the ability of ships to get out of the atmosphere on jet mode.

This little craft got to orbit with several hundred m/s left, having got a 60km Ap just on jet mode.

Spoiler

wfIFqDf.png

This is the best shot I could find. Ignore the docked tug and mini Pol lander.

Observe the fact that the wings are slightly inadequate and that it requires more control. Also observe the fact that it has a parachute for landing and I essentially drove off a cliff for takeoff.

Edited by fulgur
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20 hours ago, Mars-Bound Hokie said:

the current general plan for the descent vehicle is to land on the surface and rendezvous with a separate return craft upon ascent; that may also be the case if we send an SSTO (which also means we'll have to leave the plane).

I wish Ludlong and Co. a pleasant and successful trip.

Laythe can be quite a challenge.  Conventional landers have to hit small islands reliably through the atmosphere and there are only a couple of places that are acceptably long and flat enough, and close enough to the equator, to be acceptable spaceplane airfields.  And then there's the question of fuel to get back into  space.   Laythe doesn't have much Ore to begin with and like as not you won't have a decent amount at the few acceptable landing zones.  So you often face the choice of landing heavy with fuel for the return aboard, dropping fuel tanks from space, or setting up a complicated refueling infrastructure on Laythe.

I find it a good idea to recon the Ore situation first, then designing the actual land-and-return mission around that.  I like to send some small jet drones equipped with both the surface scanner and NBS and fly them to the various islands I'm interested in.  That way, I can spot the good LZ terrain and also know what sort of Ore is available in the vicinity. Then I can park the drones on the best places to mark them for later missions.

You might find it useful to peruse this classic thread by @Brotoro, which I found highly inspirational in my early days:.  This was long before Ore and he played stock except for things like MJ and KER.  His main strategy was conventional landers and atmospheric-only jet/rovers to explore all the islands.  Fuel to extend exploration range and for crew return came from tanks dropped from orbit.

 

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NATHAN KERMAN'S MISSION LOG: Y36D70 - 0H45M

 

Chief Engineer Nathan Kerman here. We haven't been submitting official log entries for this thread since there was nothing unique to report. Pretty much all our active-duty kerbalnauts - as well as those in reserve - have traveled to other planets before, so no surprises there. No malfunctions, illnesses, or otherwise unexpected events happening.

 

Anyway, we have arrived in Jool's sphere of influence and set up our Laythe encounter maneuver. In about 50 days, we'll be the first men to get within Laythe's sphere of influence. We'll then circularize our orbit and get some sweet science points.

lcX9hBW.jpg

 

Matster is hoping that, after we are done with our orbital runs above Laythe, we would go to Vall and visit the ladies down on Rob Mobile Base. However, Mission Control had made it clear that we were to get the orbital science and get out. After all, what good is our pod if we don't have the delta-V to get home.

 

Back on Kerbin, we've tried an air-breathing lander design - but all our attempts to get it into Kerbin orbit failed miserably in the testing phases. Outcomes ranged from wobbling during the ascent to dropping in the atmosphere. Though the lander prototypes with the whiplash engine boosters managed to get into a suborbital trajectory, the rocket phase didn't have enough delta-V to circularize - let alone make a rendezvous trajectory for a return craft.

 

ctyBzZ2.jpg

  • RAPIER engine prototype --> FAILED
    • Did not raise apoapsis.
      • Ap dropped after the craft changed its ascension angle.

 

kuenrr3.jpg

  • Whiplash Test --> FAILED
    • Craft wobbled during ascent, but wings and reaction wheels on jet engines minimized it.
    • Lander could not circularize orbit at 200 km.
      • Intended that way to see if craft will have spare fuel for rendezvous.
      • Jets flamed out at ~27 km in the atmosphere, and Mission Control is sure it will be lower for Laythe. 

 

Any ideas?

 

Edited by Mars-Bound Hokie
Grammatical error
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MATSTER KERMAN'S MISSION LOG: Y36D121 - 4H00M

 

We have established a parking orbit around the innermost moon of Jool. So that we could save fuel and maximize the photo variety, Mission Control told us to leave the approaching inclination alone and make an eccentric orbit.

Neptune I - Orbital Characteristics
Apoapsis 994.350 km
Periapsis 313.274 km
Inclination 56.7 degrees
Period 1h 32m 39.5 s
Eccentricity 0.295

 

MdaRutk.jpg

  • That's me in an EVA. I had to time the camera right in this gravity to get this nice shot.

 

Laythe looked magnificent from where we were. Though there are some small islands around, the moon is mostly heavily mineralized water. The Edith rover had done GCMS reading of the liquid and reported that the water had a high mineral concentration that lowered its freezing temperature - explaining why the moon doesn't look like a giant snowball like Eeloo. Though we ourselves won't get the chance to inspect that water ourselves, we're already the first men to see the moon's surface with our own eyes and not through some orbital probe. Even better, our inclined orbit will allow us to get pictures from a higher variety of angles.

  • We could also get orbital gravity readings of more biomes that way.

 

Back home, support for the Neptune series has somewhat remained unchanged. Walt has told us that support will grow again once we get a working ascent vehicle ready. Personally, I think we should try and go for an SSTO. However, Nathan would rather we try the jet engine lander approach.

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LUDLONG KERMAN'S MISSION LOG: Y36D138 - 0H16M

 

After over two weeks in orbit of Laythe getting pictures, we were given the order to make our Laythe escape burn. We had to wait until our orbital periapsis and apoapsis were aligned with Jool with our periapsis AWAY from Jool. In other words, we had to wait until we were in position to make a Jool orbit higher than that of Laythe's. We're scheduled to make our circularization burn in about 4 days, and leave for Kerbin in approximately 150.

 

Below are some pictures we took - and we took a lot.

COPKNih.png

  • Shot of Laythe and Jool. If you look closely at the Laythe picture, you can see a circular mountain formation.

 

3OcEJIt.png

  • The islands seem pretty spread out here. If we're going to colonize this moon, we'd better bring some ships for the water.

 

ybpMTvO.png

  • It seems like there was some volcanic activity here millions of years ago - as seen by that island. Seems like a good vacation spot for tourists, as well as a good spot to put a surface base.

 

nTkfm6C.png

  • Man, there sure is a lot of water here. I'm surprised that it hasn't frozen in these sub-freezing temperatures.
    • Matster isn't.

 

gPbeD9Q.png

  • That circular island would definitely make a good resort spot. All we need to do is make suits that can protect the wearer from the extremely cold temperatures and minerals in the water, and we're all set for underwater exploration.

 

bmxnwfZ.png

  • Photo of Jool with Vall to the right.

 

sg1INNz.png

  • Shot of Laythe after we made our Laythe exit burn.
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Your RAPIER design is un-aerodynamic. Also rocket-RAPIER designs are not very good as to get the most from a RAPIER you must pitch1 over and get to 400m/s ASAP. The idea is to get as much speed as possible on jets to conserve oxidizer due to the awful rocket ISP.

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@Mars-Bound Hokie

The problems seem similar. The RAPIER and the Whiplash come into their own when they are flown like a spaceplane. Your designs look like traditional landers, which appears to be why they are failing. Those engines are optimised so that once you get past 400m/s they actually increase thrust (due to more intake air). This means that the best designs accelerate at an angle of 5-10 degrees until you build up 'respectable' speeds (ie 700-800m/s) and then you can slowly pitch up.

However, from looking at your pictures, you aren't taking advantage of the jet engines. Rather, you are treating them like rocket engines which act best in the atmosphere. You appear to be doing a traditional gravity turn and your wing pieces do not have control surfaces, so you cannot pitch over enough quickly enough and take advantage of the thicker air. A plane-based design (it doesn't have to be a SSTO, one of the better low-tech ideas is to use wings to get into the high atmo and then decouple jet engines) is good for jet engines as you start off pitched over, however I have done a couple of rocket-based designs.

In essence, you have a couple of easily-fixed problems:

  • The orbiters are not aerodynamic enough. I would suggest using a C7 2.5-to-1.25m adapter to make the nose less draggy. This also lets you carry more fuel.
  • They do not have enough control surfaces. While you have a lot of reaction wheels, adding a set of Elevon-3 or 4s (the biggest ones) would give you better control in the lower atmo and let you save weight.
  • The flight profile does not get the most out of the RAPIER/Whiplashes. If you use a traditional gravity turn, you do not take advantage of the thick air. Instead you should pitch over to 5-10 degrees initially and (after achieving 500m/s or so) begin to pitch up VERY slowly. This will mean that you can get up to over 1200m/s on jets, over 1/2 orbital speed.

There are a couple of finer points; for example, IDK anything about your flight profile but at around 18km your Poodle will achieve maximum ISP and you can activate it then, while your jets are still running. Also, your RAPIERs should be switched to closed cycle at around 23-25km, not when they initially fall off in thrust. Basically, you want to squeeze as much speed as possible out of your efficient jets before switching to less efficient rocket engines.

One final point: testing has proved that RAPIERs (even when closed-cycle is not used) are far, far superior to Whiplashes after 400m/s. They outperform them on jet mode alone.

Edited by fulgur
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Hey, @Mars-Bound Hokie,  I was bored so I built you a simple SSTO!

Nd322hW.jpg

Link to KerbalX in the image.

Here is an album about flying it.

And since somewhere you said you were a filthy cheater you use MJ for ascents, I wrote you your very own kOS program.

Spoiler

//This is for a Rapier-only SSTO. Assuming good TWR and wing area it can pilot to orbit.
CLEARSCREEN.
SAS off.
//kOS can steer without SAS, indeed SAS is unhelpful when steering with kOS.
GEAR on.
BRAKES off.
PRINT "Ready to launch!".
LOCK throttle TO 1.
LOCK steering TO heading(90, 15).
WAIT 1.
//Wait a second so we can be sure everything is ready.
PRINT "Launching!".

LIST engines in shipEngines.
FOR eng in shipEngines {
    IF eng:multimode {
        eng:activate().
    }
}

//If it's multimode ie a RAPIER we toggle mode.
WAIT UNTIL ship:verticalspeed > 10.
GEAR off.
PRINT "We have lift-off!".
//At 10m/s upwards we will retract our landing gear.

UNLOCK steering.
SAS on.

UNTIL ship:availablethrust < 50 AND ship:groundspeed > 700 {
    PRINT "--- --- --- --- ---".
    PRINT "Thrust: " + ship:availablethrust.
    PRINT "Speed: " + ship:groundspeed.
    PRINT "Apoapsis: " + ship:apoapsis.
    WAIT 5.
}
// We have locked steering to a pitch of 15* until our RAPIERS
// produce only 50kn.
FOR eng in shipEngines {
    IF eng:multimode {
        eng:toggleMode().
    }
}
// Here we list all the engines. If they are multimode (ie RAPIERS)
// they are toggled. Note that if you are using something like Kerbal
// Atomics (multimode nuclear engines) you must change this.

PRINT "Rapiers in closed-cycle mode.".

UNTIL ship:apoapsis > 75000 {
    PRINT "--- --- --- --- ---".
    PRINT "Speed: " + ROUND(ship:groundspeed).
    PRINT "Apoapsis: " + ROUND(ship:apoapsis).
    PRINT "Time to Apoapsis: " + ROUND(eta:apoapsis).
    WAIT 5.
}

PRINT "Apoapsis 75km.".
LOCK throttle TO 0.

UNTIL eta:apoapsis < 20 {
    PRINT "--- --- --- --- ---".
    PRINT "Time to Apoapsis: " + ROUND(eta:apoapsis).
    WAIT 1.
}
PRINT "Starting burn in T-5.".
PANELS on.
SAS off.
LOCK steering TO heading(90, 0).
WAIT until eta:apoapsis < 15.
UNTIL ship:periapsis > 70000 {
    LOCK throttle TO 1.
}

LOCK throttle TO 0.
UNLOCK steering.
SAS on.
PRINT "We have orbit!".

Basically, after installing kOS you copy-paste that to the 'KSP/Ships/Scripts' folder as something like 'ssto.ks'. Then you add a kOS CPU to your craft. Open the terminal and type in 'switch to 0.' to go to the right folder, then type 'run ssto.' (or whatever the filename is) to run it. (Those full stops are very important.) You can always press CTRL+C to abort the program and take manual control. I didn't write you a landing program because even filthy cheaters MJ users can land a plane, right? Also I'm very bad at writing in kOS and so my program would probably crash the plane.

Incidentally, that program works for all RAPIER-only SSTOs, no matter how many engines they have.

That is the final, final, final thing I am going to tell you about how to design your own craft.

Edited by fulgur
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FROM THE OFFICE OF WERNHER VON KERMAN

 

It will be about four days before the Neptune I makes its escape burn from Jool orbit to Kerbin. Good thing the craft has an inflatable heat shield, or else the crew is in some serious trouble during re-entry. Everyone on Kerbin's been itching for our three brave men to return home - along with their findings from Laythe orbit.

  • We also started constructing Odin Station around Laythe. Though the process will be slow, I guarantee that it will look awesome when it's finished.

 

Unless there's something noteworthy to report, the Neptune I crew won't be logging on this journal for a while. Since several people have been to Jool already, there's nothing really new to say. Heck, we've got a mobile base with four women on Vall right now with a nuclear-powered lander and a return pod on standby. Anyway, we have been making some progress on the future Laythe missions and I am happy to announce that we have a Neptune II design ready.

qKtcvtr.png

  • We're still going with the air-breathing ascent engine approach, but to save delta-V and money we're sending one person and not two.
  • Rather than dock with a return ship. the lander can will be going straight to Kerbin.
    • I'll have to plot the return node manually, but use MJ maneuver planner for a precise execution.

 

We're still working on SSTOs for future missions. Yes, I'm aware that we already have a previous prototype that has made it to the Mun. However, most launches of that design have resulted in overheating, explosions, loss of control, or otherwise failed to reach suborbital trajectory. We eventually managed to design one that made it into LKO. Though it only had enough fuel and oxidizer for an 88-km circular orbit and de-orbit burn (for when it landed), we tested that design twice and the results were consistent both times.

hgbpjt2.png

  • Just taking off from KSC Runway 09. It's nighttime there.

 

YX8prjo.png

  • The SSTO is catching fire at this speed. We had to slow it down a bit before the nose cone overheated.

 

M7wqXg8.png

  • The plane now in suborbital trajectory, waiting for its cue to make its circularization burn.
    • Thank God the nose cone didn't blow up by then.

 

FMqhULf.png

  • At this point, we decided to name this design "Consistent" since both prototypes performed the same way when launched in prograde around Kerbin. Pretty nice shot, huh?
    • And solar panels for anyone who wants to spend a long time in Kerbin orbit. Sure, the plane has over 3,000 worth of electric charge, but we're not taking any chances.

 

iRLVdka.png

  • The Consistent had just made its de-orbit burn, flying towards the mountains. Though it looks like a loss of control during re-entry, it was just to dissipate the heat so nothing would explode.

 

1RfVqXd.png

  • The Consistent approaching the KSC at supersonic speed - and just in time for morning photosynthesis.

 

9b0XcNg.png

  • FIRST TRY.
    • Though the first prototype landed in the grasslands, both models were intact upon recovery.

 

Not a bad start, isn't it? Too bad we can only get up to two people up to LKO with that thing. I hope we make a Laythe-worthy SSTO soon, or else we may face a budgetary crisis on Laythe missions alone.

 

We're also sending an unmanned plane (and an Ultimate Relay Antenna) to Laythe with the purpose of flying around scanning for ore. However, it is launched like a conventional rocket and will enter Laythe's atmosphere like one - before flying around like a plane. To save fuel and prevent the ore scanner from snapping off, the plane will fly at low speeds above the terrain and mark down good landing and ore mining spots.

JZhoXx2.png

 

If anyone has any questions/concerns/comments regarding my mission plans, please contact us and we'll reply promptly. After all, it is kerbalkind's destiny to spread out all across the stars.

 

Wernher Von Kerman

Year 36, Day 289

5H10M

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@Mars-Bound Hokie I have concerns about your lander. It is not equipped to follow the best flight profile as you have not added control surfaces. Therefore it cannot tilt sideways and accelerate through the lower atmosphere where the jets perform best. Doing a normal gravity turn is counterproductive as that gets you out of the thick atmo to where rockets perform best, but with jets you should accelerate to over 1000m/s before 20km and then switch to rockets.

Edited by fulgur
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FROM THE OFFICE OF WERNHER VON KERMAN

 

Well, I think we did it. We managed to make a working SSTO ready for Dres - or at least make a refueling stop on Minmus before leaving. As an added measure, we had the plane land on a random spot on Kerbin's surface at least once before taking off and landing again. That way, we can know for sure if this thing works on Laythe.

  • We tested the redesigned Mun Hopper prototype THREE TIMES, and got increasing satisfaction with each one.

 

iFAWdeb.png

  • The Mun Hopper making its orbital circularization burn

 

V3TFOaw.png

  • Just reached a 90-km orbit with ~2,500 of delta-V left to spare
    • However, it can only be used by the nuclear engine.

 

ptcigo2.png

  • Mun Hopper during re-entry. 

 

mQCZBmT.png

  • Gliding over the desert after re-entry.

 

DPS5x18.png

  • Shot of the shoreline from the cockpit.

 

odDz5dp.png

  • As part of the performance test, the drills and ore converters were activated after the prototype's first landing. A day would then pass before it took off again.

 

D9B5Fhh.png

  • Nice crater we flew over. I should have ordered the pilot to mark down its location when he flew over it.
    • Perhaps we should do that next time we send an SSTO.

 

8wolmxF.png

  • Though some in Mission Control will claim that the parachutes were deployed prematurely, I actually planned it. The prototype in this photo was extremely low on fuel, and some of the engineers were concerned about the engines getting knocked off during landing and takeoff. So, I told the on-board pilot to deploy the chutes to test the "head-first" approach. The cockpit was able to withstand the impact, and the plane ended up upright. 

 

All the above photos are for the second prototype used. As for the third, we installed gear under the rapier engines just for landing and then our chances of losing engines during takeoff and landing dropped. It still performed as well as the second prototype, only we timed our de-orbit burn more accurately so that the plane would land closer to the KSC during the second landing. Overall, I think we can all agree that we are ready to use a plane to travel to other planets.

 

However, I don't think we should send it to Jool yet. As a true test of its worth in the Neptune ops, we should send it to the Mun and Minmus - and maybe even Duna/Ike - before we send one to Laythe. What do you think?

 

Wernher Von Kerman

Year 36, Day 353

5H10M

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It is really good. If you can though you should probably use a big drill, they're more efficient, and you definitely need more solar panels if you want to run the drill without cheating. I don't know your flight profile so I can't offer you tips on that, but as long as you fly like a space plane not a rocket you should be fine. If you are having trouble landing at the KSC, you should probably aim so that the orbit line looks like you will land after the island airfield.

Oh yeah, and bigger wheels make it easier to land. Use mediums.

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4 hours ago, fulgur said:

If you can though you should probably use a big drill

I thought of that, but I decided against it since it would stick out and:

  • Increase drag
    • Hence reducing aerodynamic performance
  • May explode during ascent/re-entry from overheating
  • Cause the plane to bounce when deployed

To increase efficiency while minimizing drag and my chances of in-flight explosions, I installed a second drill in the cargo bay and increased my charge capacity to ~3,000.

 

4 hours ago, fulgur said:

Oh yeah, and bigger wheels make it easier to land. Use mediums

Unfortunately, that's not going to happen. I tried that already, but the drills could not reach the ground. 

 

4 hours ago, fulgur said:

If you are having trouble landing at the KSC, you should probably aim so that the orbit line looks like you will land after the island airfield

I INTENTIONALLY missed the KSC so that I could land on various terrains and take off. After all, I'm not going to have a runway when I fly to other planets (especially Laythe). However, I should keep what you said in mind since I made my de-orbit burn too early for the second prototype test.

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@fulgur

 

I just finished with the next phase of my Mun Hopper field tests: taking it to the Mun and Minmus before returning. Though I was unsatisfied with having to take off in a RETROGRADE orbit when leaving the Mun, I could at least make a Hohmann transfer to Minmus and land on a nice ore-heavy spot in the flatlands. After refueling, I took off and made my exit burn to establish a 100-km periapsis above Kerbin. After I circularized my orbit, I landed somewhere near the badlands and waited for the pickup guys to come.

  • Though it took multiple quicksaves, I only lost my solar panels during Kerbin re-entry --> and that was because I hit "1" when I meant to hit "Q" to dissipate the re-entry heat.

 

I shall now do the next and final phase of Mun Hopper testing: flying two tourists to Duna and Ike. If I can do that, then I have Laythe in the bag.

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5 hours ago, fulgur said:

If you send it to Duna, you may want to double up your wings to make it fly better

Tell @Matt Lowne that. His wingspan's shorter than mine, and it seemed to work out well for him.

  • Not only does he have no ISRU capabilities, his canards are smaller than mine and he has no horizontal stabilizers.
  • I also have:
    • More oxidizer for the rapiers (and RCS)
    • Higher charge capacity
    • More solar panels (I have 2, he has 1)
    • Science instruments
    • Probe core for pilot-free operation
    • 2G Antenna

 

I think I'm okay flying through Duna. I just refueled on Minmus and made my interplanetary transfer node for Duna.

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The thing about Duna is that either you have lots and lots of wing, or you fly like it's a vacuum world. That is, you should use Vernors to VTOL. Or you may find yourself descending at considerable speed.

If you do keep your current design, remember to land in a canyon where the air is thicker.

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BILL KERMAN'S MISSION LOG: Y37D286 - 5H30M

 

Over ten years since Val and I were last in space; the only exception was when she and I went to test a Mun Hopper prototype, and that only managed a suborbital trajectory. Good thing we both survived that, though.

 

Anyway, several months ago, a couple of rookies (I forgot their names) managed to complete the Mun Hopper's "Worthiness Test." More specifically, a pilot and an engineer landed on both Mun and Minmus before returning to Kerbin. The only damaged sustained to the plane was to the solar panels since someone mixed up the rotation controls with the panel deployment buttons. Now that we know the Mun Hopper works, Gene has given us the green-light to go interplanetary with it.

  • And in the nick of time, too. Two men have paid top-dollar to fly to Duna and Ike, and Mortimer recommended that we use the Mun Hopper to save money.
    • 100K reusable plane > ~350K disposable lander
      • Sounds profitable, doesn't it?
  • The two tourists - and an engineer (to maximize ore production efficiency) - have flown straight to Minmus to refuel and established a 52-megameter around Kerbin before they would blast off to Duna.

xHGf7Po.png

 

Back in Mission Control, we're debating on our course of action about how to take the Mun Hopper to Laythe and back. So far, most of us say that, though it would take longer, the Mun Hopper should "hop" all the planets between here and Jool before landing on Laythe to decrease the risk of running out of fuel mid-flight. Though I agree that the Mun Hopper should make a stop on Ike before blasting off to Jool, I don't know if it's really that necessary to land on Dres before that.

  • And no, we're not sending the Neptune III yet. Besides settling the course-of-action debate, Walt wants outsider confidence in the Mun Hopper's interplanetary capabilities before we send it any further than Duna.

 

What do you all think?

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I vote Minmus-Pol-Laythe, although I will warn you against aerobrakes at interplanetary velocity with exposed drills like you have there. Do a gravity brake around Tylo, it's much safer.

I think you should go to Bop/Pol to refuel before you attempt to land. If you get to Bop orbit safely, you can land on basically any amount of fuel.

Edited by fulgur
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On 8/21/2019 at 11:31 AM, Mars-Bound Hokie said:

So far, most of us say that, though it would take longer, the Mun Hopper should "hop" all the planets between here and Jool before landing on Laythe to decrease the risk of running out of fuel mid-flight. Though I agree that the Mun Hopper should make a stop on Ike before blasting off to Jool, I don't know if it's really that necessary to land on Dres before that......

What do you all think?

it DEFINITELY will take MUCH longer to planet-hop all the way out to Jool, unless you luck into or wait for one of those very rare alignments of the planets like the Voyagers used.  The reasons such trips take so long is:

  1. Infrequent transfer windows between planets.  The farther a planet is from the sun, the lower its orbital velocity and the longer its orbital path.  Thus, the 2 distant planets move very slowly relative to each other, compared to Kerbin and the ultimate target.
  2. Long travel times between planets without spending huge amounts of dV.  You leave one planet and meet the next one approximately halfway around the sun from where you left the 1st planet, same as going from Kerbin to Duna.  Thus, the trip will take, very roughly, more or less 1/2 the orbital period of the planet you left from.  As this planet is far from the sun than Kerbin, it's orbital period will be rather larger than 1 year.  You can take a shorter transfer path but that takes more fuel, which rather defeats the purpose of making a fuel stop.

If you're that worried about fuel, perhaps you could attach a droptank to the spaceplane once it's in orbit?  

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AGAFORD KERMAN'S MISSION LOG: Y38D303 - 0H15M

 

I'm the on-board engineer for the Duna I, the SSTO assigned to take a couple of tourists to Duna and Ike before returning. Just a few minutes ago, we circularized our Duna parking orbit at approximately 20,000,000 meters above the surface.

  • 3,777 m/s of delta-V left.
    • 3,926 m/s if you re-activate the RAPIER engines.

 

Below are some pictures we took during the vacation.

 

th9K1o9.png

  • Window shot of Duna before we made our descent. 

 

CKIeuqr.png

  • Shot of the Duna I flying above the surface. Good thing there were no re-entry complications - not even the tourists complained of the craft getting hot (because the atmosphere is so damn thin)
    • Despite the fact that the nuclear engine alone gave the craft a TWR of less than 1, it was still able to glide pretty well.

 

eOS0au3.png

  • Shot of me standing in front of the craft in the lowlands.
    • We had to relocate when we realized that the canyon ore concentration was too low to activate the ore harvester.
    • At least we got some new scientific data from the surface.

 

kNxv7xc.png

  • Cockpit shot of Duna after we made our ascent.
    • After refueling the plane completely, I turned on the RCS and got the plane going up to ~75 m/s before activating the rapiers. Once we were airborne, I oriented my craft to increase its apoapsis as quickly as possible while the plane still had oxidizer in it. After the rapiers flamed out, I pointed it at a 45-degree ascension angle and got my apoapsis up to 80 km before circularizing - despite the fact that my TWR was below 1 with only the nuclear engine.
      • The MJ Orbit Info showed that, when I ascended at a 45-degree angle, the time to the apoapsis increased steadily. However, at the same time, my vertical speed was starting to gradually drop. That was why I had to begin my ascent at a high angle and get a suitable apoapsis before it was too late.

 

RlB7ltI.png

  • Ike after we refueled. Taking off and landing was more or less like Minmus - or the Mun, from what I've heard.
    • I told Wernher that I landed at the S.S. Remembrance landing flag, and I had a hill to the east act as a launch ramp during takeoff. It was almost too perfect.

 

Why am I submitting a progress report about a vacation to Duna and Ike in a thread about Laythe, you ask? The answer is simple: this trip is also a test of the SSTO's interplanetary travel capabilities before one goes on its way to Laythe.

 

Mission Control has decided that the Neptune III would stop at Ike before refueling on Minmus. However, they have yet to decide if they would go straight to Laythe after this or make another stop on Dres. After hearing about how much delta-V was left in the plane, more people are leaning towards the "Skip Dres" option. Personally, I think going to Laythe from here is possible with that much delta-V in reserve. However, I would be complacent if I didn't consider the possibility that aerobraking on our Laythe approach would increase the risk of parts getting blown up due to overheating.

 

Another elephant in the room some of us brought up was the "Return to Kerbin" phase. If the Neptune III flies directly to Kerbin from Jool orbit - even if we stop to refuel at one of the other moons - there's still the chance that the plane could blow-up during an aerobrake. A feasible course of action to slow it down would be to stop at Ike and/or Dres (and refueling) before going back to Kerbin. I addressed my concern with Gene, and he said this:

"We'll see after the plane refuels."

 

What do you all think? Here's the Neptune III Mission Plan so far:

Kerbin --> Minmus --> Ike --> (?) --> Laythe --> (One or more Jool moons (NOT Tylo) --> (?) --> Kerbin

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