Kerbal Space Program Mission #8

Munar Lander 5: Double rescue mission

Day 17

Active project: Munar Lander Project

Active missions: Munar Lander 5, 4, and 3
Current mission: Munar Lander 5
Selected vehicle: Lightning 2

Assigned crew: Unmanned

"Are we dead yet?"

While it feels like at least a week since our two astronauts have been left in orbit of Kerbals moon, the game has only let an hour or two pass while I prepare a second unmanned rescue rocket.

The Munar Lander 5 is a re-use of all the hardware previously created for the third mission, which is currently on an intercept course to Josh and Thong.

The mission badge is merely symbolic, nobody will be riding a rocket back to Kerbal.

If Lander 3 is able to meet up with their vessel and bring one home, there's no reason to fiddle with the design to do the same task.

Has space pioneering become that passe in just two weeks that we're skipping the countdown?

The rocket is launched in the same day and without a hitch, it goes without saying.  Sorry to disappoint those of you waiting for some Kaputnik-style launch disasters, but you may have to wait until I develop and begin experimenting with a larger class of rocket parts.

Following an orbital insertion burn, the rocket is set to encounter the Mün in about seven hours. This gives plenty of time to adjust the orbit of the previous unmanned vessel. 

Luckily I included this easy-to-read visualization; my readers would have had NO CLUE how complex orbital maneuvering works!

First of all, I notice a glaring flaw in my previous assessment of Munar Lander 3's interception of the two-man Munar Lander 4: they are orbiting in opposite directions. ML4 took off pointing away from the moon's direction of rotation, putting it in a retrograde orbit; ML3 never landed and is still orbiting pro-grade. It'd be like two trucks passing each other on the highway, but at speeds over 800 meters per second.

I may be cruel enough to make our Kerbals jump through space from one vessel to another parallel craft, but not ones passing in opposite directions.

We sure that's them? That could be anybody in orbit at the dawn of spaceflight.

The first course correction involves reversing direction by thrusting until the same speed in the other direction is met.  From there, a lot relies on the flight path computer to help adjust the orbital path of the ML3 until it passes by Josh and Thong's orbit within a kilometer, and the at that point adjust speed until the it shows the next time we'll pass that spot at the same time.

It's a convoluted process that would require a lot of visual aids to fully depict, so instead I will leave it at that.

You boys look like you could use a lift.

Once both craft come around to that intercept point, the Munar Lander 3 simply needs to adjust relative speed and heading to match the 4th lander to within a few meters per second. Our stranded crew only needs to wait a few more minutes as the rescue ship slowly drifts towards them.

"Let me out, I've been stuck in there for like two whole hours!"

Thong has selflessly volunteered himself to take the first rescue craft. The logic he presented eludes me still, but seeing as no other suggestions were made, I go along with the veteran astronaut's recommendation.

"Sorry Josh."

The vessels pass each other within ten meters at a velocity of less than a meter per second. Not toot my own horn, but that's might precise piloting there, especially as only one ship was maneuverable.

Open the pod bay doors, HAL.

The close encounter makes for a very easy spacewalk to the rescue rocket. One more event for the history book.

Your in-flight entertainment will be listening to the ship's computer make R2-D2 noises for the next 10 hours.

Even with the fuel spent reversing our orbit, the rocket is able to push itself out of the Mün's sphere of influence and back to Kerbin. Three more days and Thong will smack into his home planet's surface.

Well, I mean his flight plan is on course to do so. Thong's craft has its (successfully-tested) parachute and we'll be following his safe descent as the second unmanned rocket makes its approach to Josh still stuck in orbit.

But that's a few hours away and makes for a good break. I have the photos ready to upload for part two, so soon we'll be finishing all active missions with the return of our first moon missions.