Chapter 1 edits, part 2

Starscream walked to the gate of the Academy, unlike his Seeker brethren, he did not fly. His hesitated looking at the words “Cybertron War Academy” across the bronze gateway. He looked about and tipped his head toward the sky watching as yet another group of Seekers streak in, their colours glinted brightly in the sun. This caused him to think back a decade into his past. He left Cybertron on the Solar Holiday and saw the colour of his spark for the first time. His best friend and colleague, Skyfire insisted they leave that day as the solar wind would be most powerful  in the direction of the flare event. Starscream desired to stay and watch the festivities the Seekers and their rainbow squadrons would partake. Such an event would happen again in a few hundred thousand years, maybe as late as a million years. It was very, very rare. But he agreed to go with his friend, leaving Cybertron behind to visit an undeveloped world that had the potential for being rich in energy and resources.

You used a comma in the first sentence when it should be a semicolon; the difference: a semicolon imparts a longer pause to the sentence to slow readers down, so it should be "Starscream walked to the gate of the Academy; unlike his Seeker brethren, he did not fly." The first word of the second sentence should be "He", not "His"; the difference: "He" denotes the subject being discussed, while "His" denotes a possession of his being discussed. There is no possessive word after "His", so "He" should be used.

The third sentence should have an additional comment to slow it down, like "He looked about and tipped his head toward the sky, watching as yet another group of Seekers streaked in, their colours glinting brightly in the sun." You'll notice I changed the verb tense; I did this due to the progressive tense of him watching the Seekers fly in. You're using conflicting tenses in this sentence, going from progressive ("watching as yet") to present ("streak") to past tense ("glinted"). The tenses need to be consistent: since he's watching them come in (progressive) and focusing on their colors at the end of the sentence. This implies they've already streaked in, and as he progressively observes their colors they are "glinting". Another option you have for that sentence is to change it to "He looked about and tipped his head toward the sky, watching another group of Seekers streak in, their colours glinting brightly in the sun." As yet" is not necessary in this sentence, so I removed it and kept the current tense of "streak". You have options here.

For the fourth sentence, you have options here, too. "His best friend and colleague, Skyfire insisted they leave that day as the solar wind would be most powerful  in the direction of the flare event." You can either add a comma after Skyfire's name to slow the sentence down (giving readers a chance to understand you're introducing a new character and emphasize importance), or move Skyfire's name to the beginning of the sentence so it reads "Skyfire, his best friend and colleague,". You also have an extra space in between the words "powerful" and "in".

For the fifth sentence, "partake" should not end the sentence by itself, it requires a companion word, like "partake in" or "partake of". For this sentence, the former is more appropriate because it denotes participating in an event, not characterizing something (which is when you use "of").

His effort on the science mission had some promising results, that was until Skyfire got swept up in the polar storm. He let his emotions take hold, frustration, fear and grief as he searched the missing scientist who went missing. Skyfire had detected a strong Energon reading beneath the Ice Cap on the northernmost part of the planet. Starscream strongly argued against going into the colder area of the world as Cybertronians were not well adapted to cold climates, their systems were known to freeze up and malfunction and if not treated fast, death would soon follow. Energon reading or not Starscream would rather flag the location in a data report and go back at some other time, or with equipment better suited to the task. Skyfire had been a little more gun-ho about the discovery and left Starscream to study and take samples from the surface tar pits several hundred kilometres from the glacial edge of the polar ice cap.

For the first sentence, "that was" should be replaced by "that is", since this is a present tense situation (even though Starscream is reminiscing, since the reader is automatically taken back to this occurrence, it should be treated as present tense). The second sentence is confusing, I need to know what you're trying to say. You describe the emotions he felt, but not how they affected him as they searched, so they're disconnected adjectives in the sentence. How about something along the lines of "He let his emotions take hold, let the frustration, fear, and grief grip him as he searched for the missing scientist.", or "He let his emotions take hold, let his frustration, fear, and grief grip him as he searched for his missing partner." I changed the last word on purpose to convey why Starscream let his emotions take over: he was so hurt over the loss of his friend that he allowed his emotions to control him. Just calling him scientist felt too impersonal in this situation.

For the fourth sentence, it's time for a colon and semicolon! "Starscream strongly argued against going into the colder area of the world as Cybertronians were not well adapted to cold climates: their systems were known to freeze up and malfunction; if left untreated, death would soon follow." The colon shows that you're getting ready to go into detail about the situation, so I used that instead of the semicolon. The semicolon slows the sentence down and explains the aftereffects of being in the cold climate. I also changed the wording on "if not treated fast" to flow more naturally, into "if left untreated". In the sixth sentence, "gun-ho" should be "gung-ho".