The Heinlein Mission to the Mun

The 83-m Heinlein System

 Pretty much anyone who was born before me and who had an enjoyment of Science Fiction is going to recall an author by the name of Richard A. Heinlein, who in his heighday was one of the most revolutionary writers in the field, and from whom we derive the fantastic spacer adage "Once you're in orbit you're halfway to anywhere."

What Heinlein meant by this is that the single most onerous task in space travel in terms of the fuel required is breaking into orbit around a planet - such as what we do on almost every single flight, breaking orbit of Kerbin. The "burn" for this maneuver requires a delta-v of 4550 m/s, which can be quite a bit to squeeze out and is usually the largest burn on any mission.

Third boosting stage.

Heinlein favoured the moon in his writings, and I thought that today, instead of more fiddling with sattellites, it might be fun to launch a mission to the Mun. Credit being where it was do, Toddicus decided the name of the ship for me, and all this preamble about Heinlein has very little to do with anything related.

The rocket ascended rather well, powered by four titanic solid rocket boosters and two seprate liquid-fuelled rocket boost stages. In fact, thanks to having sat done to do the math beforehand, the initial maneuvering went very quickly.

 Getting a capture window I actually liked took a bit longer. I had the bare minimum amounts of delta-v required for the mission, mostly because the ship's double-payload was probably a bit over-ambitiously heavy, and I didn't want to resort to asperagus staging to get the damn thing into orbit if I could absolutely avoid it.

One you have a window though, it's as simple as pointing the rocket onto the maneuver prograde node and burning when it tells you to. Getting to the Mun is not really an achievement compared to some of the further-out missions.

Coasting in the void, farings deployed.

Sunrise and Farewell.

Why two payloads? The short answer was that I could. The longer answer is in parts - I'd never delivered a two-part payload to the Mun before and I wanted to see if it could be done at all - it can. I also have ambitions for the moon in keeping with Heinlein, namely the production of fuel from Kethane, because shipping that fuel from the moon to a low kerbin orbit would still be cheaper than flying it up from the surface of the planet itself. Physics hates space travel.

Luna spreads her wings ahead of Heinlein

So, the second part of the payload is actually a sattelite the astronauts are going to dump into Low Munar Orbit once they get there, ideally at about 14 KM. Now, this is a bit low for groundscan, but the sattelite itself has no propulsion system of any real utility, so I had to circularize the lander and the satellite in one shot. A future mission may be planned to push the process a bit further, if I can't make some adjustments with what little fuel the probe itself has.

So, with solar collectors unfurled and the burn complete, there was little to do other than to time accelerate and coast onward, but not without first taking some pretty pictures.

In orbit of Mun, post-separation

Very unfortunately, the taking of pretty pictures did not extend so far as watching the separation of Luna and Heinlein proper, since I wasn't expecting the sheer force that my decoupler was going to impart upon the satellite. I'm reasonably certain that the faring base has a decoupler pre-installed, which might save some effort on future flights.

I was actually pleasantly surprised that we made it to the moon with as much fuel as we did. I was always planning to kill the velocity on the landing stage with the same stage I used for the transfer and capture burns, but I wound up with something on the order of a third of a tank - the equivalent of a couple hundred extra meters per second of delta-v.

De-Orbit Burn, as scheduled.

What followed later was the usual space travel trope - a good ten minutes of boredom followed by a moment of sheer terror for the crew and a proper laugh for me, here related in the form of a proper story.

"Luna is away." Danburry, the Payload specialist, commented dryly for the benefit of the flight data recorder. "TLM is all good. Solar cells to full power, streaming kethane sensor data to KSC via Athos."

Inches from the surface

Flight Commander Hilbert Kerman nodded slightly, sucking a bit of overly-dry air through his helmet filters. "Roger. Rotate through one-eight-zero yaw... complete. De-orbit burn in three, two, one..."

Well, now what?

The de-orbit burn went smoothly - taken a bit longer than originally planned. Working purely on the fly, Hilbert had calculated that the remaining fuel on board was simply going to be too heavy, and would cause the landing legs to collapse under the force of the impact at the projected landing speed.

"Moving sideways a little faster than I would like," he muttered. There was only so much he could angle sideways while burning - the landing stage only had one thruster! Still, the overall surface speed was well within the calculated tolerances of the landing legs. 100m to go, then 50, then 25...

It suddenly hit home that Hilbert was to be the first kerbal to ever walk upon the Mun. He grip the steering mechanisms with a bit more anticipation than a moment ago, cutting out the fuel feed to the landing stage rocket motor.

There was a horrendous crash and a bang, a great roar of rent metal, and the whole ship was suddenly going ass over teakettle as the rocket nozzle dragged across the ground, tearing it from the ship which landed sideways with a vast impact.

Hilbert laughed a moment later, once a very agitated Samdred Kerman got done checking through his life systems. "They send up a ship with no damn ground clearance and we hit the one rock on the whole Mun!"

Now, there is some good news in this whole process. As near as I can tell the return stage and crew capsule weren't actually damaged, and I happen to be on a bit of an incline. I think there's enough torque in the system that I could potentially take off on an angle... with a perfect transfer orbit and generous aerobreaking on kerbin, there's no reason it wouldn't work.

We might try that next time, since they have no way of calling for a rescue mission.