I can usually work out what the base key of a track is, but this one had me stumped and, for the first time, I had to ask what the chords were. The first section is straightforward enough, it turned out (Emin7, A7, Dmaj7), but the second was completely beyond me. Still, once I knew the key, I could do the rest by ear, since I don't really have the theory to work out the "proper" notes.
Sometimes it takes me a long time to work out a few lines for the solo, but this was a short piece with two clear sections and it didn't take long at all. A little practice to get it all in one go, and I was there.
I recorded it without reverb and added it in Reaper using the TAL Reverb 4 plugin, which is a nice and simple, to give a properly spacey feel. Finally, I'd fluffed the ending very slightly by not allowing the note to ring as long as I wanted, so I added a synced delay (iZotope DDLY plugin) on the last couple of seconds to extend it slightly.
Here's the final result: