Ad Astra Per Aspera: To the stars with difficulties.
Ad Astra Per Derpy Aspera: To the stars with Derpy difficulties. 
Lightning Dust strands herself on her way to the red planet. With no way to move her rocket, she'll die unless Equestria's Best and Brightest find a way to bring her home despite cloak-and-dagger sabotage, snobbery, limited resources, and bureaucratic incompetence.
Content Note:
Death - Mentioned in the Prologue and Chapter 5. Chapters 7, 9, 10 (spoiler): Touched on: miscarriage.
Narcotics - Chapter 14 - Performance enhancers and blood doping discussed.
Sex - Inappropriate government-required questions in Dossier chapters; Ch. 11- a slightly saucy section.
Show Era: After Season 9.
Cover Art: The background Mars is by Kevin Gill with license to only the background Mars cover art at this link. The pony interposed on Mars is by owlicious, who also combined the two images.
Special Thanks: to owlicious for edits from the start through the end. 
EDIT: Oh, I was right, this is a submission for the Wonderbolts Sitewide Contest
None of them seem right.
Looking at a fleck on her helmet instead of the planet- that would be unlikely since she'd move her headShe put on her helmet twice in a row? I don't think I read a part where she took it off. I can't tell if the helmet falling off was the doom, or if it was implied that (1) she lost her helmet without noticing, or (2) she was losing too much air despite the helmet, and was confused/hallucinating/etc.Or it was just implied that she looked back later.EDIT: The story was updated
11882220
Thank you for playing along with the theories! Lots of creativity! I will comment more on them after the answer is revealed.
RE: The Wonderbolts contest:
- We will see!
- I also have another story I have been aiming at that contest (which permitted two stories), but that other tale may not get far enough along, which is a pity. If only the Wonderbolt contest could have started a few weeks before it did when I had more time to write. Alas and alack and all that.
11882230
Good catch. Thank you!
Fixed by ending the second paragraph with its penultimate sentence.
On second thought, something else seems more likely. I missed the parts about using rockets rather than flight magic earlier and multi-stage being rockets rather than a flight plan. Based on knowledge of orbital mechanics (kidding) from Kerbal Space Program and the Martian - there usually isn't much budget for extra fuel(delta-V) in space programs, to save on costs and weight for the craft, crew, and supplies, so if there's more fuel use than expected (loop-de-loop almost definitely not in the flight plan, and possibly close to moon sized, and
requiring full reversal of speed, twiceor probably just a slowdown for orbit, then speedup to leave orbit, which would still require extra fuel) there might not be enough for landing on Marred, the return trip, or re-entry to Equestria.- especially if she wasn't paying attention to any orbital mechanics lectures, which is something I'd have to guess at
- Same about needing to drop whatever weight they could in the spacecraft in the Martian's book/movie return trip, etc.
Not really related, but funny - https://what-if.xkcd.com/126/ (Stairs to space and how much butter you would need)
what-if.xkcd.com/imgs/a/126/options.png
Really good grammar overall aside from minor nitpicking on the chapter, moved to an ongoing proofreading conversation.
11882318
A fair comment. Agreed! I split it into its own paragraph as a fix. The 'she' was immediately following the reference to a "test pilot", but it now reads much better split into multiple paragraphs with less ponies per paragraph.
It also provided me an opportunity to turn the parallelism of three sentences into near-parallel paragraphs after some limited expansion. 
I think you are correct that the comma is best here. You are also right that occasionally a comma is not necessary, but I agree it is better in this situation. Thank you.
I agree the solid em dash is more ideal but there is no way to generate a solid em dash on my keyboard (or automatically). I would need to manually cut and paste, (more ideally) memorize and type an obnoxiously long keyboard shortcut (ALT+0151), or write the story in a word processor with a feature that automatically converts.
My workaround has been the double hyphen to represent an em dash. Noted that you prefer "details -- a view", with the spaces; however, "details--a view" is equally acceptable. I will keep in mind if there is a large contingent of reader preferences for the preceding and trailing spaces. My preference is for less spaces due to convenience, since less characters are typed (less of a chance for a typo), due to aesthetic preference and due to aural preference because an em dash sounds jumbled together without a pause.
Thank you again for the suggestion, however!
11882463
Again, I'm enjoying the story and looking forwards to the rest of it, and there's really good grammar overall, aside from minor nitpicking in a few places that are now fixed.
The rearrangement looks better, I have no complaints about ambiguity in the rewrite of the paragraph, and other comments were fixed. Looking forward to the rest of the story.
You do know that her name is not really derpy right it's muffins no seriously look it up that's her actual name in the show
11882220
11882290
Thank you for your guesses!
You put in a lot of thought. Many of your postulates could have been the answer. And then you arrived at the right one with your comment on "definitely not in the flight plan"!
You mentioned the Martian and I would cite the Martian, Project Hail Mary, and The Right Stuff as influences along with other sci-fi stories, portions of Changeling Space Program, histories of the space race, and nonfiction books on early rocketry technology development, so if those sort of things interest people, you'll probably see glimmers of them here.
Loved the twist ending.
Will she end up like https://en.wikipedia.org/wiki/Elon_Musk%27s_Tesla_Roadster and need a lot of rockets or an impressive feat of magic to try to rescue? I'll wait for the next chapters to find out
EDIT: For readers imagining how Doctor Hooves acts and speaks (excited, British accent, scientist), see the below show clip about "Derpy and the Doctor" at 1 minute and 47 seconds in.
11882844
It's only mostly canon, and plenty of authors and artists ignore it.
Look at the tags on this story (and Fimfiction generally). The character tag is Derpy.
And on the tags available on derpibooru. She is Derpy Hooves there.
Even in merchandise, her name is rarely "Muffins"; it is usually a picture of a muffin and/or her face. Because it's not her name; it is the substitute Hasbro decided to use in place of her name.
I'm looking forward to more updates.
I'd liked that story and expanding the canon.
My headcanon for an outdated version of this chapter about a lab mouse was that it became inedible, similar to the scene in the below video.
11884514
Something I found funny to imagine in James T Kirk's voice.
These are the voyages of Equestria's first ponynauts. Equestria's first three missions: To explore the red planet. To rescue the first ponynaut. To boldly go where no creature has gone before!
On second reading and with the elaboration added to the author's note (the day of this comment) giving context, I'm really loving how this prologue fits in with the rest of the story (theme, events, explaining background/motivations, etc.), and I'm looking forward to the other chapters of the story.
I'd missed a few things because I read it too fast the first time.
good topic for a story
11886229
Less than 100 people have even opened the story (I assume some of the 101 views of the first chapter are repeats and my own). 
Thank you. I hope it delivers for you and that it finds an audience!
11884846
Only a few more chapters left now!
Thank you!
11888368
I'm looking forward to the conclusion of a story I personally found similar to The Maretian or the Changeling Space Program (and the various other works you've linked)
Hopefully, they'll get back by both returning on a trajectory close enough to home for a third group to rescue them later. Maybe the species will finally cooperate for the rescue, but I assume ponies would have reasonable plans that didn't rely on external help, so I don't know. (Alicorn/other help? Finishing another rocket?)
I had the idea for the below non-canon edit picture of the concept of Derpy being trapped on Marred, for the events before chapter ten, for non-serious memes, etc.
"We just don't know what went wrong"
(Below: Twilight seeing Derpy on Marred, edited for Marred to be much closer than the Moon to make the test pilot easier to see)
images2.imgbox.com/0f/b9/4udNSAV7_o.png
And for just Derpy (edit of this) on Marred with the current cover art of the red planet. The red planet is from NASA's 3D model of mars, and use of their images for non-commercial purposes with attribution are generally allowed by their guidelines.
images2.imgbox.com/55/e9/GzVXGVMD_o.png
Edit: Oh, I missed the part in Chapter 5 about oxygen, as well as the oxygen Device having finite resources in Chapter 6: Lightning Dust Continues / Twilight Tries / Spitfire Doesn't Make the Grade.
Original comment from when I thought the issue was fuel and the Device was magic is below:
I've been assuming all launches were from ground level, so I think it's mostly a matter of saving fuel for the launch to Marred and back.
They'd save fuel if there was a way for Twilight to teleport or accelerate the rockets before the launch, but if they called Discord then she probably can't, e.g. if it was sent to the moon (spells to transform items, seal them inside other items, reduce effects of gravity, etc.).
Even for helping with launch it from within Equus, Discord might be trying to avoid leaving any traces of his chaos magic whatsoever, for any being like Cosmos that might exist and be capable of sensing chaos magic (Dark forest hypothesis)
11889267
Those are excellent images!
Thank you for the fanart!
11889934
11889267
Thanks!
11889267
EDIT: Second concept cover based on https://mlp.fandom.com/wiki/Derpy/Gallery?file=Derpy_flying_through_the_hoop_S4E24.png
images2.imgbox.com/42/5c/CpkFfdPQ_o.png
And a meme version (Interstellar and The Martian were space rescues of characters portrayed by Matt Damon.)
images2.imgbox.com/54/d0/peerxaQ0_o.png
EDIT: additional concept cover fanart/meme with an edit to the above post, inspired by the cover of "The Martian", which had similar themes
images2.imgbox.com/7f/05/A4wT2KKg_o.png
Other concept fanart of potential covers, based on discussion several chapters ago when I was still speculating on the ending (same picture, with title and shifted pictures)
images2.imgbox.com/7e/f9/mmhJjsSC_o.png
Firefly: HEY! thats my line!
So in other words, Lightning Dust should just kill herself now and save herself the trouble?
Best and Brightest refers to several members of the team as a whole.
The thing that Derpy's the best at in this story is brought up in the first chapter, then explained in more detail later, current/former Wonderbolts were also in the space program, and the reasoning for the choice of pilot is explained in the story.
(aside: comments on the story page (about a quote in the story description) confusingly show up as comments on the most recent chapter at the time of posting)
11889267
All good plans.
Why didn’t you reply to my comment?
There was nothing to respond to. No question was asked. If you read through the comments section, you may also note I do not respond to every comment.
If you meant me by "you", I originally forgot to click the reply button, but then it felt like an unwanted notification if you didn't have plans to read the story, and redundant if you had already read the story. The original comment was an ambiguous rhetorical question (somewhat of a funny joke, but would confuse new readers about the story contents), and I didn't want to start a discussion unrelated to the story.