Boy does Dennis Tito have a deal for you! How would you like to take your wife on an all-expenses-paid tour of the Solar System? You’ll have plenty of time together, do a little sight-seeing, and be famous when you get back. Sounds great, doesn’t it?
Well, as always, the devil is in the details. Tito’s idea is that we can use an upcoming set of planetary coincidences to send our first people out to Mars. Because of the relative positions of Earth and Mars, the whole trip can be done in 501 days. You’d leave Earth on January 5, 2018, and spend 227 days coasting out to Mars. Once you got there on August 20, 2018, you’d turn around immediately and spend another 274 days coasting back to Earth before skipping through the atmosphere a couple-three times and finally splashing down on May 21, 2019.
The math for the flight trajectory works out just fine, although a lot of people are asking if it is worth it to spend 501 days in a space capsule just so you can spend about six hours screaming past Mars. Especially since you’ll be flying over Mars’ night side and so won’t be able to see much of anything in the way of scenery; a quick glimpse of sunset with two moons, another of sunrise and that’s all folks! Tito’s argument is that this is similar to the Apollo 8, 9, and 10 missions that flew from the Earth to the Moon and back without ever landing. Without those missions, there would never have been an Apollo 11.
But it is far from clear that a “Mars 1” would ever lead to a “Mars 2”. There is neither the level of international competition nor the level of public interest in a trip to Mars that the trips to Luna had. To be fair, Tito feels that this trip might kick-start the public interest, and he could very well be right.
Far more serious objections come from the nature of the (as-yet un-built) flight equipment and the cost of the flight. Tackling the costs first, this expedition is expected to run between $500 million and $1,000 million . Tito is putting $100 million of his money where his mouth is, and is prevailing on other entrepreneurs and businesses to come up with the remaining funds; advertising and sales of related merchandise are expected to be a significant part of the funding. He does not anticipate using government funding for the trip.
But he will use government brains. He (or more specifically, his company) has already signed a Space Act Agreement with NASA Ames Research Center to develop the heat shield that will be needed if the lucky couple is to survive the experience. And he is drawing on established companies like SpaceX  and Bigelow Aerospace for launch capability and housing.
But even with the leg up those companies can give, this will indubitably be a crash course. Inspiration Mars has less than two years to get everything built and ready. If they miss this launch window, then the next one won’t happen for 18 years . And that has led to a reduction of the mission to its barest essentials.
How bare? There won’t be any EVA suits, because they take up too much room in a cramped Dragon capsule. There won’t be any showers or even sponge baths, as that is too wasteful of water. Instead, disposable baby wipes will be used for both bathing and cleaning up after what NASA euphemistically calls “waste elimination” and everyone else calls “taking a dump” . Food will be minimized, as will clothing . And there won’t be any special instruments along for the ride; a few standard cameras and a radio and that is it. By keeping everything down to the bare minimum, the mass of the system should be low enough to be launchable in one package . This will cut back on costs and complexity, which means that the mission has a better chance of launching on time.
So here’s what the flight will look like, really: You and your lovely wife  will spend 2014 training for the mission. What to expect. How to fix things when they break. How to tell the press to go suck an egg in six different languages. And then you’ll launch. The first twenty minutes will be sheer terror, with shaking, loud noises, and pieces falling off of the vehicle. (Don’t worry; they are supposed to do that.) Then you’ll spend the next 227 days catching up on your reading, learning the ins and outs of zero gee sex, making and erasing the world’s first zero gee sex tape, fighting, making up, having make up zero gee sex, and sending message after message back to the Earth about how wonderful space is and how beautiful the stars are. You’ll see Mars growing larger and larger and the smells in the capsule slowly get more and more intense; fortunately, you won’t be able to tell about the smells . You then spend six hours trying frantically to take a zillion pictures of Mars as you swing by its darkside and then you’ll spend another 274 days coasting back to Earth while you repeat the joys you experienced on the ride out. When you get back to Earth, you’ll dip into the atmosphere at 9 g and pop back out to cool off, then do it again and again. When you finally land on Earth, you’ll be whisked away to a press conference where everyone will ask “What was it like?” and leave it ambiguous as to whether they mean the view or the sex. You may notice people slowly moving farther and farther away from you and it won’t be until you take a shower in your hotel and see the layers of brown and smelly crud (and see your clothes standing up by themselves) that you understand why.
 To put that into perspective, a single B-2 bomber cost $773 million and we built 21 of them. And a single F-35C fighter is expected to cost $238 million and we’ll build 560 of them. For the cost of those two (out of hundreds) DoD projects, we could do this Mars trip 150 times!
 Those who remember Heinlein’s classic The Man Who Sold the Moon are probably smiling right about now.
 Though rumors are swirling of a secret rift. Early announcements (read: more rumors) had Inspiration Mars and SpaceX doing this in unison. Now SpaceX is just wishing them luck. Make of that what you will.
 Which is not to say that the trip cannot be made; flight windows nearly as good open every decade, and every couple of years there is a nice launch window for a 1000-day mission. But this quickie mission won’t be possible again until 2031.
 Amusingly, what NASA calls “taking a dump” (throwing waste outside the capsule through a vacuum lock) is what everyone else calls “waste elimination”.
 This is already a problem on the ISS. T-shirts there go from in the wrapper to “use for interviews” to “wear when visiting” [a] to “everyday wear” to “gym wear” [b] to “use to clean dirty things” to “why hasn’t this been thrown overboard already?”
 And that brings us right back to the Apollo missions. Von Braun wanted Earth orbit rendezvous. The different parts of the system would be launched separately and then assembled in orbit (preferably at a space station) before heading off to the Moon. But it would have taken an extra couple of years to develop the system, which means that we wouldn’t have met Kennedy’s arbitrary “by the end of this decade” deadline. And so we went with the faster lunar orbit rendezvous and ended up with nothing to show for it after Nixon cancelled Apollo.
 And you both were chosen for your ability to get along for long periods of time. That you both happen to be photogenic as all get out is merely an added benefit.
 Two effects are at work here. First, smells travel poorly in space, due to the low air pressure and poor circulation, coupled with fluid build-up in the sinuses. Second, human senses detect changes in intensity, not the absolute value. So a slow increase in stinkiness is never noticed whereas a sudden burst is; this is why you don’t think that you smell bad after a day working in the field but do realize it when somebody farts.
[a] There is a distinct US side and USSR side to the ISS. This is not due to politics per se; it is actually because the Russians tried to charge everyone else for using “their” part of the ISS facilities (mainly the bathroom). So the Americans said “Fine – you can’t use our bathroom, either” and let everyone else use it for free.
[b] Astronauts on the ISS exercise two hours a day in an attempt to stave off bone loss and boredom. It works for the bone loss.