The International Space Station orbits the Earth once every 92.69 minutes. Orbits of Kerbin are even faster.Second installment of Dawn, a KSP 0.90 career. Time to explore Duna. Our brave Kerbalnauts set foot on a new world for the first time!
The improvements to career mode in 0.90 makes interplanetary exploration much more challenging and fun. In previous versions, money was pretty plentiful. Now it's scarce. We constantly want all the money we can get our hands on to upgrade our space center, build spacestations, play with new designs, and so on.
Which means missions. A lot of missions.
Also, not using quicksave, as we are doing in this game, makes money more scarce. Some non-trivial proportion of missions are going to fail. So if we are only doing one mission every few years, and it goes badly, it just takes that much longer to build our base!
Doing more missions simultaneously requires more careful planning around launch windows. We need to see which launch windows are coming up and decide which missions we are going to focus on. Preferably, we'll be able to "quest stack" - do five or six missions with just one or two spacecraft.
A short primer on interplanetary launch windows: due to the nature of orbits, spacecraft can only launch for other planets at certain times.
To reach objects in Earth orbit, the launch window really doesn't matter much. We orbit around the Earth so quickly, if we miss the transfer window for, say, the moon during one orbit, we can just wait an hour or so for the next.
The International Space Station orbits the Earth once every 92.69 minutes. Orbits of Kerbin are even faster.
But when going to another planet, the orbital period that matters is not the time it takes us to orbit the Earth. The orbital period that matters is the time it takes us to go around the Sun. And we only orbit the Sun once a year. If we miss a transfer window, we have to wait a year for the next one.
... more or less. It can be more than a year or less than a year, depending on how fast the other body is orbiting the Sun. Also the relative orbital inclinations of planets makes some transfers impractical.
Also some planets' orbits are highly elliptical. Which again makes some orbital transfers impractical.
But those are details. The heart of why you have very specific, infrequent launch windows for orbital transfers to other planets is that it takes a year to orbit the sun. If it only took ~90 minutes, like orbits around Earth do, you could launch whenever you wanted and just grab the next transfer window.
(Also, if we had warp engines from Star Trek, or any other super-fast sci-fi engine, the transfer window wouldn't really matter much. We would have so much thrust we would just brute force our way wherever.)
So anyway, the POINT of all this is that we had a transfer window to Duna (Mars) while New Dawn was still on its way to Eve (Venus).
So we designed our second interplanetary ship Ambition for a simultaneous Duna mission. Here's Ambition:
Ambition weighs in at just under 33 tons. It is composed of three autonomous spacecraft.
From top to bottom:
Without further ado, here's Ambition on the launchpad:
The rocket that will get Ambition to space is the unimaginatively named KR-2L Booster. The first stage is 12 solid rocket boosters (SRBs), followed by the second stage: a KR-2L engine with 4 big orange tanks full of fuel. This second stage is a fully functional spacecraft in its own right. It will make it to orbit then separate from Ambition and land on its own.
The KR-2L Booster can get ~35 tons to Low Kerbin Orbit (aka LKO aka Low Earth Orbit aka LEO).
In general, this basic design of SRBs on the bottom with a fully recoverable second stage has served me well in career mode. The SRBs can't be recovered, but they are cheap, so that's not a big loss.
The second stage is smaller and more efficient than it would be without the SRBs. It handles pretty well and lands easily. Without SRBs, the second stage would grow so huge that it would become clunky, difficult to control, and difficult to land.
The Ambition launched without incident. The KR-2L Booster separated without incident and landed safely. Then the Ambition fired its three nuke engines and headed for an intercept course with Duna. (No pictures of this part, sorry.)
Half a year later or so, Ambition entered Duna's gravity well. Duna and it's moon Ike are just specks in the distance.
A small course adjustment was made and Ambition was all set to flyby Ike.
We made one more small course adjustment so Ambition would use Duna's atmosphere to slow down (aka aerobrake) and remain in orbit around Duna, instead of flying back toward Kerbin.
Ambition is getting awfully close to Duna at long last!
ACK! ERROR! So Ambition aerobrakes but the thin atmosphere of Duna is not nearly enough to slow us down enough. We should have flown much closer to the surface of Duna where the atmosphere is thicker. As it stands, Ambition will be flung out of Duna orbit into open space.
Engines to the rescue! Ambition fires its three nuke engines. This wastes a fair amount of fuel, but Ambition should have enough extra that it will still be able to complete it's mission.
Success! Ambition officially becomes the first Kerbal spacecraft to achieve orbit around Duna. Party!
We do one more aerobrake so that Ambition drops into a lower orbit of Duna.
Ambition collects gravity readings and visual observations from every biome of Duna, both from high orbit and low orbit.
This orbit is good for reaching Ike, so we detach the Maven probe here.
We detach the Ambition lander here with Camfrid at the helm. If all goes well, he will be the first Kerbal to set foot on another world!
Shortly after detaching, Camfrid realizes all the science gathered in Duna orbit is still in his capsule. If something goes wrong with the landing and the Ambition lander is destroyed, all that science will be lost too!
He grabs the science results, straps on his jetpack, and exits the lander. Then he cruises over to the Ambition tug, stores the science results, and returns to the lander.
Success! The science is safe!
Ambition flies low over the Duna terrain. There's no going back now. Time to land!
Success! A Kerbal has has set foot on another world for the first time! Party!
Stay tuned for the next installment to see Camfrid's return to Duna orbit, rendezvous with the Ambition tug, and the Maven probe's mission to Ike!