Story has merit; Writing and editing are sorely lacking.
My critiques and comments (most were sent to author):
1) LANGUAGE PROBLEMS There are numerous places in which your word choices are incorrect (wrong word entirely, or typos, perhaps, and misspellings) or words are missing or doubled. BTW, I don't mean differences between Australian/British-isms and American English. I mean WRONG. Since you are writing for young people, I find it especially disturbing that you misuse words or have "waste" instead of "waist," for example.
You also have sentence fragments, inappropriate paragraph breaks (usually, not enough), and other structural mistakes, including a serious problems with commas, that a good editor and/or proofreader should have caught.
2) PACING PROBLEMS Chapter 9 is a disaster. It lags, it sags; it was so hard for me to slog through it, I almost didn't continue. Too bad, because chapters before and after it are so much better.
3) CHARACTER PROBLEMS The way you develop and present these kids' characters, their ages are indistinguishable, inaccurately depicted or indeterminate. For example, I had no idea Freddie was 19 (!?!) until a recent look at a blurb, since she comes across as about 13 or thereabouts, while Pierre seems to be about the same. The "younger" kids do not come across as appreciably younger, either, except for the toddlers/babies. As an educator who has worked with kids of all ages for decades, I know what I'm talking about.
4) FACTUAL PROBLEMS There are many scientific or other inconsistencies that I won't go into, but you definitely need a fact-checker and someone else, perhaps, to check through for aspects you claim are true, making sure they consistently come across throughout the book.
5) MORE CHARACTER PROBLEMS There are so many issues with the robots I don't know where to start. Perhaps there is some other information you have that readers do not? I could not understand how they are different (or why) from one another, nor why they exist as they do or who supervises them. By the end, I still could not understand why some "went crazy," some "mourned," and some just went on as usual.
Part of the issue is that you have too many characters whose names start with the same initials and no distinguishing features between robots' names and humans' names, so I can't keep it straight which are which most of the time. You make readers work too hard when you don't make these types of understandings easier to track.
There are hints that perhaps the robots (or some) have been co-opted or usurped by the aliens, perhaps, but that doesn't explain their blurry origins.
7) INCONSISTENCY PROBLEMS Kids born on Mars (or en route) would NOT have knowledge of so many Earth references or experiences unless they're watching DVDs extensively. For example, how would any of them know about someone/something's being "possessed" ("The Exorcist"???)?
8) PREFERENCE/GENRE PROBLEMS The satanic-like chant thing going on is very jarring and out of place. Not liking the horror-like aspects at all and questioning the appropriateness of that for middle-grade readers. There are many other ways for the beings communicating this message to do this: why make it scary?
9) Your POV changes mid-paragraph, sometimes, and keeps shifting through the book, but not in measured, appropriate ways. For example, at one point near the end, Jacqui seems to be the narrator but then it's Freddie but then it's Jacqui, so that the brother becomes the son becomes the husband.... Very confusing and inexcusable, even if you're self-editing.
More importantly, for POV, it's important to choose a narrative perspective and stick to it. If your perspective is third person NOT omniscient (which you seem to be going for), then the particular character through whose eyes we are seeing the story unfold cannot know anything, speculate on anything,have vocabulary or thoughts that this character would not logically know/have. It's all right to change that, chapter by chapter or even section by section, but make it very clear to the reader whose eyes we are now seeing the story unfold through each time you switch. Double- and triple-check ALL aspects to make sure those are indeed components this particular viewpoint would know/have/own.
10) The "heaven"/"coma" experiences that also penetrate many of the settlers dreams is never explained fully, nor are these beings. Why is that? Since they are so crucial to the story, why are their intentions and roles so confusing and mixed? I was left with more questions than answers. The ending is not an ending. It's all right to pave the way for a sequel, but you left too many loose ends.
I wanted to like this story, particularly since I 'won" it in a contest. I love sci-fi, especially stories that feature and are geared to younger readers. PLEASE revise this?