Mission to Moho (mostly failed)

[Bekiekutmoar]

I play this game frequently but yesterday I realized I've never landed a Kerbal on Moho. So a mission to Moho was being prepared and some factors were taken into account; being close to the Sun, Moho has a (very) high orbital velocity, aerobraking isn't possible, and the orbit of the planet is heavily inclined ... ! So the KSC came up with this creation:

The transfer-window was already there and therefore the escape-burn began ... ! 3 brave Kerbonauts would go where no man (at least in my game) had gone before.

After the initial burn of between 1500 and 2000 m/s Delta-V the computers calculated the ship would arrive 'too early', or ahead of Moho. A correctional burn of around 850 m/s was needed and after 26 days another 1650 m/s Delta-V was required to match orbital inclination with Moho. The extra fuel-tanks (see first image) where completely depleted and the main tank of the transfer vessel (named Grotesque) was 15% depleted. When entering the SOI of Moho, the relative velocity shocked the crew: 4550 m/s ... ! Returning to Kerbin with this ship was out of the question. The retroburn began early to avoid overshooting the planet and ending up drifting in interplanetary space.

Relative velocity was reduced to around 2100 m/s when the fuel-tanks of the transfer vessel were completely depleted. Too fast to achieve orbit around Moho and the crew was about to be shot into interplanetary space, where the chances of being rescued are slim due to the enormous distances. There was only one option: the Lander ... ! One Kerbal could go into the capsule while the other two would hold onto the capsule outside.

The mission descended into complete chaos. Pieces floating around everywhere, Kerbals falling off the capsule.

Two Kerbals ended up floating in space and about to be shot into interplanetary space, but they luckily managed to reach the Grotesque (y'know, the transfer vessel). Although they are now stuck in a solar orbit, at least they can enjoy a spacious and pressurized capsule. The third Kerbal actually managed to set foot on the surface of Moho, but is also unable to go home. Long story short: do not underestimate the Delta-V needed for a succesful mission to Moho ... !

[Odo]

You really should have put a kerbal in the rover chair instead of on the ladder...

Other then that, fun read I really like how you assembled the ship in orbit. I need to start doing that, then I could get farther then Duna :3

[Bekiekutmoar]

I tried it, but realized too late that putting a Kerbal in the rover seat is done by right-clicking the seat itself ... !

Well, the Kerbal on Moho decided to drive to a nearby crater for some nice scenery, but he forgot one important thing ...

Parking brakes ... ! Now the rover lies on the bottom of the crater in several pieces.

[Odo]

Aww. hahah the seat laying on the ground made me laugh :3

[Tw1]

Next mission- a rendezvous in Kerbol orbit?

[Geschosskopf]

Good, dramatic story. Wish it had a happier ending.

Coming up from the ground, Moho requires really big rockets due to the need to lift a top stage with enough delta-V just to stop there, let alone land, take off, and return. It seems rather better to assemble the thing in orbit, but that requires several fairly large launches itself, so on the balance isn't really any easier. All in all, not an easy place to visit. But on the plus side, windows come around about once a month so you can keep on trying, and thus get to witness many spectacular failures .

[DMagic]

That capture burn can really be a pain; and it varies hugely based on how good your intercept is. My strategy is just to completely ignore Moho's position when I start the transfer. I usually do the transfer burn near Kerbin's descending node with Moho, then I can either launch into the right inclination, or make the change in Minmus orbit, where my refueling station is.

Once I get into solar orbit I just setup the intercept like I'm docking. I burn retrograde when I'm at periapsis (which should coincide with Moho's orbit) just enough to setup an intercept with Moho. Sometimes I have to wait a few orbits to get the timing right, but doing it this way is so much easier than trying to get a perfect intercept directly from Kerbin orbit.

My best flight from LKO to a stable, 100km orbit around Moho was around 4800 m/s I think. So you don't waste too much by using several smaller burns instead of making a single capture burn in low Moho orbit.

[Bekiekutmoar]

It sure is a challenging target ... ! I'm preparing a rescue-mission as we speak. It'll take some time to construct a decent ship in orbit.

[Bekiekutmoar]

Right. I'm using a Grotesque-class vessel again with extra large fuel-tanks docked behind it. The combination still needs a lander, crew, refueling, transfer-window and then off to Moho.

[Bekiekutmoar]

After some orbital construction the rescue-ship was completed and the mission started. After the initial burn another 800 m/s burn was needed to correct my route into the SOI of Moho. Gotta say the rescue-mission looked pretty optimistic at that time.

However, the crew realized far too late another correctional burn was needed to lower periapsis to around 300 km and that resulted in another 800 m/s wasted. Could have been done with just 50 m/s or so if correctly timed ... !

Relative velocity when reaching the SOI of Moho was - again - around 4500 m/s but eventually the rescue-vessel managed to go into orbit. Two problems however; the orbit was polar and just around 280 units of liquid fuel (and 300-something oxidizer) remained in the tanks of the transfer vessel. Not enough to return to Kerbin and probably too little to reach Eve.

However, a lander managed to pick up the stranded Kerbal from the previous mission and might have enough fuel left to go into orbit again. The KSC decided to halt new manned missions to Moho and is planning to send unmanned fuel-tanks in the (near) future to save the 7 Kerbals stuck on and around Moho.

[Bekiekutmoar]

Looks like KSP-version 0.21 is going to break compatibility with current saves and ships, so I gotta step up and wrap up the current space-program. This includes pulling back 2 Kerbals stuck on Eve, 3 Kerbals in an equatorial orbit around Moho and 2 more Kerbals stuck in solar orbit. The plan is to fabricate unmanned ships that are totally dedicated to refueling stranded vessels in remote locations. Such a ship would consist of many smaller tanks that can be disposed when depleted, thus increasing TWR. Its gonna be difficult but its possible.

[Bekiekutmoar]

Update: the KSC decided to focus on the Grotesque-class ship that was stranded in orbit around Moho. This ship flew to Moho to rescue Lensfrey Kerman (the kerbonaut that got stranded on Moho during the first mission), but ran out of fuel and needed rescue itself. The KSC refused to send any more kerbonauts to the innermost planet, and instead launched an unmanned collection of fuel-tanks into space. Eventually, a lengthy burn and some corrections afterwards sent the unmanned craft to Moho.

Relative velocity in the SOI of Moho turned out to be around 5360 m/s, a brilliant new record ... ! Nevertheless, after slowing down and matching orbit with the stranded vessel, enough fuel was left to completely refuel the ship in question. The crew was delighted when they realized help was nearby, and dumped the now empty lander.

Rendez-vous and refueling.

The Hohmann-transfer back to Kerbin began when the planets were correctly aligned. The journey back home wasn't without problems and some extensive correction-burns were needed to reach the SOI of Kerbin, resulting in 95% of available fuel being used. Kerbins SOI was reached 50 days after leaving SOI of Moho.

Relative speed increased to almost 5700 m/s just before entering the atmosphere, so the transfer-vessel got roasted thoroughly and its solar panels shattered in a matter of seconds.

But the crew survived the BBQ and were happy to eventually set foot again on their home planet. Meanwhile, the KSC planned a rescue-mission to the vessel still stuck in solar orbit ..... !

[box_brain]

Gonna be hard to get those guys in solar orbit .

[Synthesis]

Not sure what's more exciting--the failed mission or the rescue! Great stuff!