The
Jool Orbital mission has been carried out, and most mission objectives have been successful. Having spent 135 days being readied in a 250km high orbit of kerbin, the ship left Kerbin's SOI and initiated a Jool transfer burn as planned. Ship's systems performed as expected, and after the 22 minute long (!) burn the ship was injected on a collision trajectory with Jool.
The
Jool Orbital, making it's escape burn.
This ship carried the last 5 probes of my Zond program, the first 6 already landed on Duna, Ike, Eve, Gilly, Moho, and Dres. It's mission objective: probe Jool's atmosphere and each of it's natural satellites.
Detaching the aft drop tank that has been drained of fuel, while on a collision course with Jool. The tank was equipped with basic systems needed to operate scientific instruments, chutes, and comm equipment to transmit it's findings for as long as the onboard instruments remain operational.
The
Jool Orbital making a correction burn after deploying the probe / tank. This burn put it on an aerobreaking trajectory and also had a purpose of delaying it's contact with Jool's atmosphere in relation to the probe / tank (in further text, I'll refer to is as the
Jool Impactor), allowing me to focus on the probe while the
Jool Orbital is still roughly two hours away from atmosphere contact.
The
Jool Impactor, getting closer to Jool's atmosphere. Comm equipment deployed, all scientific equipment operating.
I monitored the
Jool Impactor as it descended. As expected, atmospheric pressure and temperatures began to rise exponentially as it got below 20km altitude. Just a few meters (one, actually) above the surface, it was picking up some 15 atmospheres and approximately +980 degrees (I assume °C since the rest of the units are metric). Yikes, whatever comes down there isn't coming up.. Unless you let the game glitch; in previous versions some of my dropped tanks which I allowed to impact Jool proceeded straight through it and ended up on some weird, extremely elongated elliptical orbits around the Sun. So this time when the probe went below surface, I hit "end flight" and focused back on the
Jool Orbital.The
Jool Orbital after having made a successful aerobreaking maneuver. The down side of me being focused on the
Jool Impactor probe while the
Jool Orbital was approaching was that I failed to correct for a 12 degree orbital inclination in time. Correcting this took a lot of Δv, which in turn cost a lot of fuel. Due to this development, I was unable to manually carry the probes to some of the more.. problematic to reach Jool's moons. Instead, I deployed one to Laythe and Vall, and then used the remaining fuel aboard ship to settle the
Jool Orbital in a 14 million km circular orbit around Jool, hoping the high orbit would give the probes enough of a head start to reach their destinations.
Deploying the
Zond 11 to Laythe. Incidentally, I love sunrises over Jool.
First of the probes reached it's destination. So far, so good.
Time to put another one on Vall.
Reached it with enough fuel to spare to light a zippo. Briefly. Scientific analysis: it's blueish grey and kind of boring. On to the next one!
The next one attempted to reach Tylo. I say attempted, because after the probe reached a 50x50km, landing on Tylo safely would require over of 2km/s of Δv. The probe simply didn't have that much left, so I left it in orbit instead.
The next one went to Pol. Pol is further than Tylo, much smaller, and on an inclined orbit. So why, you might ask, would I even try to reach it when I couldn't land on Tylo? The answer is, the further away you get from a body you orbit, the less fuel you need to climb literally millions of km. And Pol is much smaller so once you do reach it, you actually need very little fuel to land. In fact, my distinct impression is it's entirely doable with RCS only, and it probably wouldn't take more than a few units of monopropellant. Main problem in reaching Pol (and Bop) was that their orbits are very much inclined. I didn't have enough fuel to do plane change burns of that magnitude and reach the targets, so I had to catch both moons while they were on a point where their orbits intersected my own. The new node system makes this a bit easier, since you now have ascending and descending nodes that tell you exactly where those orbital intersections are.
BTW, I love Pol. It's surface isn't grey and boring, it's small but really irregular which makes landings interesting, and sunrises over it are awesome with Jool appearing larger than the Sun
Lastly, using the same method I used to reach Pol, the final probe arrived safely on Bop. It's gravity is very, very low and it's surface is very uneven, which makes landings fiddly. If you touch the surface that is angled in relation to your probe, it will bounce back, and it will take some fine RCS control to make it settled down. Scientific analysis: cool tiny irregular asteroid captured by Jool, but not as interesting as Pol.
Final mission results:
- probe Jool's atmosphere with a disposable drop tank turned probe: success;
- land a probe on Laythe: success;
- land a probe on Vall: success;
- land a probe on Tylo: failure. Probe low on fuel in a stable 50km circular orbit. Probe is equipped with a docking port so future refueling operations would enable it to land.
- land a probe on Bop: success.
- land a probe on Pol: success.
Status of
Jool Orbital: in a stable 14 million km circular orbit around Jool. Very little onboard fuel remains, so it will not be possible to use it as a refueling depot. Other systems operational, and the ship is now used as a comm relay between the probes and Kerbin.
The
Jool Orbital after having deployed all of it's probes and spent a vast majority of it's fuel in a high orbit over Jool.
All in all, I'm calling this a win as I'm considering ways to refuel the Tylo probe, enabling it to land on it's intended target.