You are going away, to some place isolated... in space, of course. You will only be around one other person. You can take an allotment if 1GB of personal media with you (text, video, music, games, pics, etc.) that you will be able to access in your free time indefinitely at will.
The other person will also take 1GB with them, but you won't be able to talk to them until you're on the journey.
You will have access to any knowledge resources to perform your function and keep you alive. You will never return to a point where you can get new external media. Any additional media you ever access would have to be created by you and or your travel partner with what you have access to.
You will also not know the sex of your partner, but they have willingly taken the same risks to embark on the journey as yourself, and will have a similar mission.
I think text is going to be the most dense, information wise. With plain text you could fit about 2500 average length books in 1gb, that's not considering any compression.
Additionally, you could create a novel representation of words to reduce the total amount of text and include a key to expand it back out, replacing common groupings of letters like 'ch' with 'k' for example
If you could get a 2:1 compression ratio from your modified alphabet and a 4:1 compression ratio from traditional compression algorithms you could get up to 20 thousand books! That's a book a day for 55 years,
I think music is gonna take up way too much space. Compressed all the way down to 32kbps which is going to be a pretty miserable listening experience (everything will sound underwater) you are only going to get ~75 ish hours of music.
Cut that in half for a more tolerable 64kbps.
It's a decent amount of music, but not a lifetime's worth of your only entertainment imo.
Edit: for some context on audio, 320kbps mp3 will only net you 7 hours of music.
Hmm, well what else can we bring? Guitar and strings? How much of the day is busy with work, and how much left for recreation? If we aren't going to be busy then yeah I would love to read. But it takes my whole attention. Music can play and work, so if our time is mostly spent working and sleeping, it would help a lot.