How can I humanely kill a stranded Kerbal?

So I've got a stranded kerbal in sun orbit with no fuel or resources except for the EVA jetpack. I'm playing Demo, so there is absolutely no hope of me bringing him home in a rescue mission (docking parts not availble). I have honestly no idea how I ended up stuck in sun orbit anyways (a failed moon landing attempt).

I think the most humane thing to do in this situation would be to end the little green guy's life quickly so he doesn't have to spend infinite years alone and stuck in a capsule. How can I kill this Kerbal in my current situation?

PS: Preferably a humane way that does it quick, but I won't be too picky so if it isn't I don't mind.

The most humane way to end his agony is to terminate the mission in the Tracking Station. To do it, follow this procedure:

1. Go to the Tracking Station.

   

2. Make sure the astronauts are marked to be shown on screen. It they aren't, just click the astronaut icon on the top of the screen.

   

3. Select the aforementioned kerbal from the list of objects or click it on the main screen.

4. Click the Terminate button on the lower left panel.

   

5. A popup window will appear asking you to confirm the action.

   

6. Click Terminate to confirm that you want to terminate the mission and kill (humanely) all kerbals on board.

This method is quick and painless (at least for you) and it helps remove clutter (sorry - no offense) from the list of managed objects.

Seriously, any other way to terminate this kerbal is just cruelty.

Besides, space administration is business. Get over it.