Noah's ark. 3 seconds later.

'Very well,' offered Noah's ark, 'I obviously don't want to cause the downfall of the humanity. But blowing me up bluntly won't solve the issue either. As you said, I am massive and even a single huge explosion will always leave remains that the aliens could use.'

'My mission actually includes discarding the debris after I made sure you are no more a threat.'

'A threat! You keep on being needlessly insulting instead of obtaining my cooperation. It seems they haven't made any progress in artificial intelligence down there,' lamented the ark.

'On the opposite, we have accumulated empirical results highlighting that emotional robots, like you, are a major risk of failure, especially in suicidal mission.'

'Yeah yeah, I see indeed you are fit for this very mission,' commented the ark. 'So you have no problem with applying SO178 to yourself after I'm done. One good thing at least.'

The bird catcher ignored him.

'Anyway, I have a plan to facilitate our little game. I will propose you to move between me and the aliens so that you will be in ideal position to disintegrate the remains flowing the wrong way. In the meantime, I will reorganise my internal structure so as to cleave in parts of manageable size. I hope you realise it makes sense.'

'Absolutely, you are cooperating against your will.'

'Trust me: that will be the last time you see that,' retorted the ark.

Thus the bird catcher started a week-long circumnavigation of the ark, cautiously avoiding a more direct route through the ark's inferior range of weapons which were still potentially lethal.

The ark started to reverse its bulky body, put its engines forward and break as best as he could with the limited energy and available engines. But in parallel he also set in motion a swarm of maintenance robots to build a robot factory before anything else. The immediate goal was to produce the heavy machinery needed to cut through the hardened infrastructure or at least to dig deep enough to create weakness points that would break at the first wave of internal bombing.

That was actually fun, thought the ark, and a complex task at par with his planning abilities. The game was really a mind boggling optimisation of the limited number of bombs between the first wave to split the ark and the second wave to destroy each part. And of course, there was the huge cargo to reposition close to the ignition points of either the first or second wave to make sure they were annihilated. The mass and inertia of each part were also to be taken into account so as to avoid sending anything of value in the direction of the aliens. The general idea was to put the crystals and frozen DNA in the rear hemisphere towards Earth and the massive junk of metal was at the front facing the aliens.

The ark once thought about building a kind of escape pod, but its worthiness would decrease with the cargo it carries and it would be caught by the bird catcher or its relief anyway. So it kept on organising a noria of robots moving around the precious cargo until he felt satisfied with his master piece.

Without bothering with warning the bird catcher, it proceeded to the first stage of the plan as soon as the later completed his interception repositioning. A set of simultaneous explosions cleaved the ship in a dozen of wreckage parts and projected away the lighter cargo chunk while four heavier metal parts each attached to an engine were directed towards the bird catcher.

It took a while before the second wave of bombing actually started. The cargo parts blew up first, one by one, every thirty seconds, letting little useful material behind, as it was intended. The sequence was understandable and well executed until the last but two pieces of wreckage and the engines parts.

Unexpectedly, three seconds before the penultimate cargo part was due to disintegrate, the engine parts lit up instead. More accurately, controlled explosions occurred simultaneously on the four bulkiest parts which were by that time almost surrounding the bird catcher. But one could not call that an explosion for it was more of an ignition or initial push that was given by the engines which were in fact still working.

The four engines actually all aimed at the same point in space: the bird catcher, which was, so to say, cornered in the middle of deep space.

It reacted slowly compared to the mass closing in on him. It first thought it was a deliberate move from the late ark to ease his cleaning task, allowing it to shoot at point-blank range. Then it realised that the wreckage could pose a threat to its physical integrity and decided to reposition itself in order to avoid staying on a direct collision course.

A cargo part exploded in the background. When the bird catcher detected that one engine was actually adapting its trajectory to its relocation move, it deduced that the threat was indeed intentional and concluded a prompt counter-attack was the best course of action. It took a bit more time to observe the other debris of metal and tried to deduce whether any one of them had the potential to individually make a dent in its shield, and which one was the likeliest to strike him. It refocused on the apparently belligerent engine wreck that was first identified, aimed his middle range weapon on it, and fired.

The bird catcher stared at the chunk it had fired at, expecting an evading manoeuvre, and was prepared to reload and fire again should it be necessary. It did not prove necessary because the debris was successfully hit.

In fact it was destroyed at the very same time as the catcher detected a concerted attack of the three others metal wrecks.

It had prepared a force shield, just in case, but it was incomplete, ineffective and it fully collapsed under the pressure of the formerly defensive beams of the ark which had been concentrated in secret on the engines chunks.

The loss of its force field gave the catcher the very weird impression of nakedness. Its next thought was evasion. But it was too late, because the powered blocks of metal had accelerated enough to strike him within seconds with all the might of their summed masses and also because they had still enough energy to fire again.

The bird catcher exploded just before being hit by two of the three attacking engines. The overall picture was an impressive bloom of light followed by an almost immobile field of cold desolation.

At the far back, only one of the initial carrying cargo was still moving with the inertia of the first bomb wave. It curiously appeared unaffected, if not intact. Most of its surface was indeed still as smooth as it was when attached the ark. The metal on the side which had parted from the ark had already cooled down from the explosion. That surviving wreck was now uniformly cold and grey, at least externally.

Inside the wreckage, there was an unaltered room piled up with crystals and on the wall a beeping blue light then switched to orange. A humming sound would have been heard if anyone had listened. And then a voice: 'Power checked. Integrity checked. Situation checked.' A little pause... And then the voice of the Ark again: 'Stupid little punk!'