Now that I have done it, let me say that rejecting a manuscript is not a fun task. I agonize of selecting that option from the pull-down menu. I do not do it casually, and please know that I and the other editors think very carefully before deciding on rejection (rather than allowing for a revision).
That said, there is a mandate to authors that submit manuscripts to JGR-Space Physics (or any scientific journal): that the paper is presumably ready for publication at the time of submission. This seems obvious and most authors adhere to this philosophy, but it is worth stating as a reminder to the community. Please don’t submit a half-finished analysis with the intent on finalizing the study during the review process. Please don’t submit an incomplete motivation and literature review with the expectation that the referees will fill in the missing references. Please don’t submit a partial description of your methodology in the hope that the omitted details of the technique, data set, or model will go unnoticed. Please don’t submit a manuscript in need of technical editing to correct and tighten the English usage, waiting for the reviewers to do this for you.
It is expected that authors include everything necessary to convey the original contribution to the field, including all necessary discussion of the motivation and methodology, in clear and readable language. Furthermore, it is expected that authors do not include extraneous text, figures, or citations that are not pertinent to the central focus of the study.
I truly hope that authors do not intentionally submit a less-than-complete manuscript, but it happens because the paper writing and editing process is long and authors can be distracted by fine-tuning minutia and forget the larger scope of the full paper.
My suggestion is that, just before submission, authors read through their manuscript one last time, in its entirety from beginning to end, not only to correct grammar and spelling but also to insert or remove words, paragraphs, figures, and even sections to make the study as complete as possible without including anything beyond what is needed to convey the central message.