Bay 12 Games Forum

Kethane scanning probe time.


_{The marketing folks assure us it's better with the solar panels extended.}

The probe has a bit over 1900 m/s of Δv. That's more than enough to get to Minmus from orbit and get a nice, roughly-circular orbit. I'm aiming for a polar orbit, around 100 to 150 km above the surface, which I'm hoping will give me a decent balance between orbiting quickly and not being in the dark too much.

Because of the efficiency of the LV-909 and the size of the probe, we just need to get this little beauty into orbit. It's still night, so don't expect many screenshots. I'll give you one here, since I forgot to take one of the VAB for this simple little rocket.


_{I don't really need the adaptor, but I've got excess Δv even with it.}

The initial TWR for that Poodle is a measly 1.02, so takeoff is slower than the Skipper with Mainsail boosters we used to launch the rig. Which completely failed to not spin. Anyways, this technically-SSTO craft is simple enough to launch. I seriously contemplated how much of the launch I could do in the background while doing other things. I do note, however, that adding some kind of control bit would have probably been a good idea. Gimbal and probe reaction wheels aren't really enough for a good, quick turn.
Around the four-kilometer mark, I notice that we've gone through half of our fuel. Even though we're not even going a hundred m/s, I turn the throttle down to 2/3. My speed starts dropping. I turn the throttle back up. I do turn down the throttle a couple ticks around 8,000 meters, with the velocity being around 160 m/s. The gravity turn is pretty quick, although--not for the first time--I need to go steeper than the 45 degrees I always guess at first.
14,000 meters. Fuel's below a third. I'm starting to wonder how much that Δv map I'm using needs to be adjusted to account for low TWR and air and stuff. I'm flattening out my trajectory by 25k, watching my fuel dwindle and my apoapsis rise. By 40,000, I'm at 10 degrees and 10% fuel. Apoapsis: 50k. I'm probably going to be doing orbital injection with the probe.
51,600 kilometers. I hit escape as the apoapsis hits and passes 70k, and well...


_{How often do you have almost exactly 1% fuel at a time like this?}

I burn for a few more seconds, to push the apoapsis another several kilometers up. It's now more than two minutes out. I hit the staging button, then the x button, then I set up a maneuver node.
Let's see. I have 50 kN of thrust, a 1.25-ton probe, and hence accleerate at 40 m/s². The upcoming burn is about 400 m/s. That means it'll take about ten seconds!
...


_{A post-staging estimated-burn-time that's actually accurate?!?}

Awesome. And that only took like 30% of the probe's fuel.
I set up a maneuver node for correcting that 6.1 degrees of issues. Naturally, KAC warns me about the node right after I start fiddling with it.


_{Successful maneuver planning.}

While I wait for the maneuver node to show up, I extend the solar panels. Sure, we're on the dark side of Kerbin, and we've got a third of a battery left, but I don't want to forget.
We maneuver, burning another 250 m/s of fuel.

Finally, a maneuver just a few minutes out, to actually intercept Minmus's orbit. Again, as I'm starting it, KAC warns me of an upcoming maneuver node. It doesn't take long for me to get an encounter.


<sub>I can't remember how I ever managed without the Xrise Estimation method!
...Oh, right, I didn't.

Crashing encounters? Not ideal.</sub>

Time runs low, so I need to go with that crashing encounter. I'll...figure something out before I crash.
900 m/s. This is about half my tank.
Alright, we're done. How much have we lost from the inevitable errors?


_{...Problem solved!}

Alright. We're on a Minmus encounter. We have under 14% fuel, but that's okay, because we still have 332 m/s of Δv and only need about 80 to get into orbit. More, depending on how fancy we want it, but eh. I quicksave to avoid weird issues like last time, then warp ahead to the SoI transition.


_{The probe in all its scanny glory.}

Our periapsis is now almost 950 kilometers out, but eh. Now for a maneuver node.


_{Okay. This will take most of our fuel. Then we'll need to burn more to get into range. Who designed that Δv map?!?}

Thankfully, remaining maneuvers are insanely cheap. Thankfully, because I have less than 100 m/s left. I observe some graphical bugs...


_Whoo.

...activate the kethane detectors...and warp six days to the node.
Less than 12 m/s in this maneuver. It'll be tough not to overshoot, but I'll try. I slip up a bit, surprised by how fast the bar drops even at minimal thrust, and yet I hit it almost perfectly.
I make another maneuver node, four days and change out, that will bring the probe into a stable 127/128 km-orbit.


_{And it looks like it won't be in the dark often. Yay!}

It'll be 34.3 of our remaining 85 m/s. We're almost done.


_Waiting.

As we approach, I hear some pings. Kethane-detecting pings.
I do the burn slowly and carefully, and almost perfectly. The apoapsis is a couple kilometers higher than intended, but the periapsis is the same, the orbital period is a few hours, and...we've detected a solid trace of "not kethane".


_{All our data at this time.}

Alright. Two questions.
1. Do kethane detectors detect kethane while you're focused on other vessels?
2. What should we do next?