Art: Full marks. I think maybe the cover art/logo doesn't sell the rest adequately, because it looks a bit basic, but then the rest of the visual presentation is a pleasant surprise.
Writing: I think it's a good story and there's nothing in the writing that's particularly distracting or confusing. There's maybe too much repetition for a format where space is at a premium. E.g. the "what's really going on" repeats a lot of information from the front of the pamphlet, when you could use that space to go into more detail about the Sun Gremlins. As an editor, I also feel like there are some places where you're reaching for a fancy word and not quite using it right, when a simpler word would be just fine. E.g. it doesn't make sense to say the Ikkari was "jettisoned" past the light barrier... the ship was thrown out of itself? Thrown, hurled, catapulted, launched would all be fine.
Game Design: I love the idea of using the environment itself as an enemy. It almost doesn't even need the Sun Gremlins if there were more timed mechanics, raising the heat level as the scenario progresses. One thing I'm not clear on is what protection the players have. The section on Module Conditions suggests you're just automatically taking damage every round in a Condition 5 location, but the Drop Zone suggests players have hazard suits that will buy them a few minutes. And then the back panel has stats for Cryosuits? Were you originally going to do this on the cold side of the planet and forgot to change the suits?
Theme: I was going to give this part marks because it seemed like the only mythology was around Markham's "legendary" flight. But I twigged at the last minute that "Ikkari" is probably a reference to Icarus. Might be better to just be overt and call it the Icarus.
Layout: It looks clean, but there are some things that appear twice and probably don't need to. The Sun Gremlin stats also appear in two places, as do the rules for attaching cables to the hardpoints. Probably don't need to put the goals in two different places either (even though they're redacted in one of those places). Finally, I think it's pretty important to have the map and the location descriptions on the same side of the page if at all possible, as flipping back and forth constantly is going to be a pain.
Utility: Could be turned into a 5/5 easily post-jam if you address the map issue and clarify what kind of protection the players have and what, if anything, triggers heat levels to increase.
Favorability: Conceptually, easily one of my favorites of the jam so far. I get the sense that most of the issues I have with it are probably related to running out of time and rushing at the end? Anyway, love it, full marks for favorability, and hope you'll tighten the screws after the jam.