I doubt anyone will agree to that.
They might add some equipment for long-term survival on the planet, just in case they cannot go back. That way they'll survive until rescue comes.

Most of fuel is used during take off and Mars needs less than half of that.

Great... thanks, dude.
The sequel would be, obviously, a prequel.
"Day 0 We're on descent-- what? I can't say >>re-entry<< Jackson! We're the first one's here, right? Anyways, gonna get back to my seat, and buckle up. You be good to your mom junior, ya hear me? Good. Johnson out."
"Day 1 Just a first impression but... wow. Just, wow. This place is... so empty. I love it!"
"Day 5 We're on the good way to make our first martian base operational. The Mar Base Alpha. Gun' be grand, yo!"
"Day 7 I've been assigned to my very first martian mission. After setting up our habitational hubs, I've been tasked with covering them up. With the sand, that is. Or dust? I'm not really a geological specialist here, but that thing sure is weird in touch. Like a fine powder, but hard and sharp - Tyrone got cut too. Anyways, since we've already recovered all of the machines, I can get ready to dust some dust!"
"Day 9 Something strange occurred today. I was out, running the duster as usual, when something shiny caught the corner of my eye. I turned there, but the flash was gone. I turned back, and the light was back too - just at the corner of my right eye. It was annoying, as I moved there and again for a while, trying to spot the devil, but in the end I blamed it on the Sun. Damn you, Sun."
"Day 11 I tried to ignore the shine that had haunted me for the past two days, but I couldn't blame the Sun any longer. The angle didn't add up! I radioed the capt. that I'm going to take a walk, stretch my legs and whatnot, and went to the spot that I was suspecting to be where the flash occured. It was just a rock. A plain, well, medium-big orange dusty rock. I leaned over it and--*looks up, lips move up and down a few times*-- gotta check those samples Rosy talked about. We're gonna have us some carrots!"

Day 23 of Martian Mission - Houston-Mars Control Stephen Hourtowsky and General Victor Hossenpot via comms with capt. Abigail Trump - excerpt.
Hourtowsky: "How's your feedback, captain?"
Captain Trump: "Loud and clear, those new relay antennas are holding up I see?"
H.: "Couldn't be the any other way. How's your crew holding up?"
capt.: "All too well if I may say so. They're still fired up. A couple of stitches over a fight won't make them fall."
H.: "So I heard. Are they alright?"
capt.: "We all talked about it. We all apologised, and kissed, and we're one big happy family again."
H.: "That's good to hear, and--"
General Hossenpot: "If I may-- I haven't got much time, ma'am."
capt.: "Oh, of course. I'm sorry general, and it's nice to finally meet you."
General: "Likewise. I'll get right to the point. Did you or any of your crew members experienced or had shown any of the symptoms on your screen?"
*capt. Trump's face looks down onto computer screen, eyes widen for a second, then her face goes up, perfectly still*
capt.: "What's this about then?"
General: "Did you, or did you not saw any of--"
capt.: "No, I haven't. Sir."
*video goes black for a view seconds, unintelligible, a couple of words break through the static: "virus," "probability," "cease operation." Then captain appears again, alone this time. Feedback from her living quaters.*
"Computer, set the perimeter closer by 100 yards."

"Day 90 Today's anniversary. Well, sort of. But IT HAS been whole three months. It's like a whole year here. Not really, no, it isn't, yeah I know Rose, stop doing that. You're doing that, but you're going to drink with us, right? Yeah I know what you *Johnson stands up, and moves away from the camera, footsepts can be heard, and then laughs* gonna do girl. You gonna get it low tonight, yo! *voices eventually die out in the corridor. The camera keeps running for a few more minutes until it shuts down automatically."
"Day 92- Hell. Damn. Oh hell. Je-sus. Listen up... you hear that? You hear that sound? It's OUTSIDE. No- no, you can clearly see, that we're going OUT. Yeah, It keeps on running for a couple more minutes, like five or ten. It's like vibrating, high pitched sound. Here, take those headphones. Wait-aaand... there! You hear that?
-Wow. Is this real?
-Yeah, I guess it is?
-So, what is it, a meteorite?
-Girl, what kind of meteorite would do stuff like this?
-You're asking me?
-You're the geologist here, right? You tell me!
-What's going on here, folks?
-Oh, it's John, he says that-- *Johnson can be seen quickly shaking his head* he's bored out of his mind. Again.
-Oh, I thought that... nevermind, I'm bored too.
-Wanna do something then? Play--"
"Day 129 It's been bugging the hell out of me. This sound. It should originate from the hubs just outside, but when I went to check it was only rock there. No change in the dusty cover either. Maybe it was some kind of weird meteorite that got caught up in some weirdly well timed dust devil?"

*the following video shows a speeding red image, that eventually stops, revealing red rocky ground. The camera moves forward for a couple yards and then stops. It goes dark after a few minutes.*
"Day 132 What are you doing here, little fellow, huh? Were you shining at me? Huh? Weird."
"Day 133 About the samples you brought back yesterday.
-What about them?
-I couldn't drill a hole in them.
-Then use smaller drills? Or those diamond ones?
-Dude, who the hell you think I am? If I say I couldn't drill them, I mean it. Nothing worked.
-Okay, then keep them. There's a transport arriving next week, they will take it back, and examine on Earth, cool?
-Yeah, cool...
-What's up? Something's bugging you?
-...-- No, it's nothing."
"Day 139 Relax. Breathe in, breathe out, breathe in... you okay? What happened?
-I... it doesn't matter. It's stupid.
-Rose, tell me. It won't hurt you, remember?
-Yes, I know.
-So? What's going on? Is the dream back again?
-No, it wasn't that. This time it was.. it was a real nightmare. A real.. nightmare. I was talking samples down at the sector Z, that crater, right?
-Yes, I know.
-So, you know how dark it gets there sometimes? So... I was there, but I was going further than usual. Past the shadow line, and I-I couldn't stop! I just kept walking, like if something was calling me, and then the sunlight was gone, and I was all alone, except... I wasn't - all around me--
-Whispers?
-Yes? How did you-- John? You alright? You look pale. John? John!--"

"Rise and shine day 140! It's the day I'm finally getting off of this rock! And instead of packing and getting myself ready and all, I'm taking care of yet another victim of space delirium. Oh, poor Johnson. Oh poor me."

"-So, what happened to him?
-He.. passed out.
-Like what... during sex?
-No! No, we're not like that!
-You sure are. So what happened then?
-Well, he... kind of woke up, and then had this seizure and...
-passed out?
-Right."

"This is E-MDIV! We've reached the designated entry point, may we proceed?
-This is Mar Base, you may. Welcome to Mars.
-Roger! Please stand by for provisions!
-Provisions? Wait, aren't you--
-E-MDIV out!
-Hello? Respond, please! Mar Alpha to E-MDIV, respond!"

"Alert! All crew members for emergency meeting now!"
*wuuuuuuub bass*
"You're saying, that we're stranded?!"
*wuuuuuuub bass*
"IN A WORLD FULL OF RED COLOR"
*wuuuuuuuuub bass*
"AND CREEPY RED ROCKS"
*wuuuuub bass*
"MANKIND'S LAST CHANCE OF SURVIVAL IS.."
*wub bass*
"TO SCREAM LOUDLY INTO A NETWORK OF SMARTLY BUILT-IN PERSONAL CAMERAS"
*random loud screen shifts*
"AND A VAST OTHER ON THE MARTIAN BASES. EVEN THE ONES BUILD IN A HURRY"
*children laugh, for no apparent reason*

"STARRING
DWAYNE "ROCK" JOHNSON AS THE VOICE BEHIND ROCKS, AND JOHN JOHNSON
EMMA STONE AS THE GIRL THAT DIES FIRST AND ALSO ROSE
AND MICHELLE RODRIGUEZ AS THE HOT-BLOODED CAPTAIN WHO WILL KILL SOME ROCKS. AND THEN SOME MORE.
AND OTHER INSIGNIFICANT CREW MEMBERS
IN

THE MARTIAN(S) ACTIVITY

It's already a game on Kongregate.
www.kongregate.com/games/scriptwelder/dont-escape-3

Round trip? There's no round trip to Mars, dude.

It depends on the planets relative position in their orbits. At worst when mars is on the other side of the sun it takes something like 3 years to get there, absolute fastest with current tech is a bit under 6 months I believe, although speed is only limited by how much fuel you carry, so you could make a giant flying fuel tank that could get there pretty fast if you really wanted

I know about ion drives they are fantastic for fuel efficiency but have terribly low thrust like you said, they are good for little probes and stuff but unless we make them a lot more powerful it will take months to usefully accelerate an interplanetary ship, which brings in lots of its own inefficiencies

Also I should point out this was not a gravity assist or "sling shot", which uses the gravity of a body to pick up speed, it was a simple hohmann transfer

Fair enough, but in this about the simplest orbital manouever you can do, although since its planet to planet you have to be pretty accurate

Im not sure how familiar you are with orbital mechanics, but curiosity's transfer stage needed quite a large amount of thrust to move the spacecraft from earth orbit to martian orbit. The whole burn was completed well within earths gravity well, because its far far more efficient that way. This was done with conventional liquid fuel rockets. If you used ion drives you would need to burn for a much longer period of time to produce the required change in velocity, and the further away from earth you get while doing this burn, the less accurate and efficient the burn becomes. So even though Ion drives are more efficient, the longer burn time means they spend less time burning in ideal positions

KSP is pretty good for learning the principles and getting a feel for how things work in space, so no worries. Its actually what got me interested in all this stuff to begin with