Space -- There's nothing quite like it.

As a whole, space is unlike anything on Earth. That's why humans go there -- to explore and experience the unique environments beyond our world, from conducting scientific research in the microgravity of orbit to bringing home rocks from the surface of the moon.

But even if there's nothing on Earth that's completely like being in space, there are ways that you can prepare for your extraterrestrial trip without leaving the planet. If there's nothing on Earth that's completely like space, there are things here that are somewhat like space, at least.

The basics are easy enough -- most of the time astronauts spend in space consists of being inside spacecraft, and you can prepare for that by being in a model spacecraft. From the very beginning, astronauts have used spacecraft simulators to learn how to operate the vehicles they will be flying aboard. Research teams have also used this sort of simulator to study challenges of long-duration space missions -- running a full-length simulation of a Mars mission, including keeping the crew confined together for 500 days, has shed light on the unusual psychological and logistical issues that such a mission would present.

That kind of analogue is simple enough. It doesn't require a unique environment, just build a model of a spacecraft and go. Children have been conducting low-fidelity versions of this simulation in their own home for decades using bedsheets or cardboard boxes. But if all there was to being in space was the experience of being in a spacecraft, there would be no reason for rockets to leave the launchpad.

One of the most unique parts of being in orbit is the experience of free-floating in microgravity, and you really can't capture that on the ground. Above or below the ground, kind of, but not on the ground. You can capture some of the experience underwater; there are things you can learn about floating in space by floating in water. An even better analogue of the orbit experience, however, can be found aboard a reduced-gravity aircraft flight. These aircraft, sometimes affectionately known as "Vomit Comets," flying large parabolas that cause their occupants to experience almost half a minute at a time of weightlessness. For a brief period, you're floating like you would on the space station.

If your ideal space trip involves going beyond Earth orbit, there are locations on the planet that will help you prepare for your destination. Spend time in the desert, and you'll learn a few things about walking on the moon. (Minus the low-gravity bouncing, of course.) Visit a frozen polar wilderness, and you'll be better prepared for the harsh condition of Mars.

This week, astronaut Dottie Metcalf-Lindenburger will lead a crew that's beginning the latest in a series of simulations NASA conducts in an underwater habitat. The NASA Extreme Environment Mission Operations, or NEEMO, missions take place in the Aquarius underwater lab near Key Largo, Florida. The combination of the laboratory and underwater environment allow the NEEMO missions to simulate the experience of spending time inside a spacecraft, of venturing outside the vehicle into space, and even of conducting surface operations on another world. The current NEEMO mission, NASA's 16th, will simulate a mission to an astroid.

Metcalf-Lindenburger goes into the simulation knowing what the real thing is like -- being in space, at least, if not going to an astroid -- as a mission specialist on the 2010 STS-131 space shuttle mission to the International Space Station.

But long before she became a NASA astronaut, Metcalf-Lindenburger had begun her journey toward space with an analog of a different type -- one that provides simulated experience with everything from operating the space shuttle to walking on the moon to going on spacewalks to working in Mission Control.

And the best part of this simulation is that anyone can participate, without having to be an astronaut or travel to the polar ice caps. Metcalf-Lindenburger was the first -- but not the last -- NASA astronaut to start her path to space at Space Camp, a path that has now led her from looking down on Earth aboard the Internationals Space Station to commanding a mission in the depths of the sea.

Include Space Camp in your journey, and who knows where your path could take you?

Contributing Author: David Hitt