Let's get one thing straight before getting started: An aerospace expert I am not.

When I was in a meeting last week and asked a Foolish counterpart where growth in aerospace could come from, I was surprised to hear him say, "Space flight could be one, but it's still largely on the horizon."

"You mean it's actually possible passenger flights into space could actually happen?" I thought to myself.

It's already been done
Maybe it's because I've spent the last six years as a teacher, grading students' writing assignments, but I completely missed the fact that private space travel had already been accomplished. Funded by Microsoft co-founder Paul Allen, SpaceShipOne took to the sky all the way back in 2004, becoming the first private, manned vessel in outerspace. So in an attempt to wrap my head around a potential game changer, let's take a quick look into a possible hot spot for aerospace investors.

The players
Though many of the companies involved in this young field get their funding from private sources, there are several publicly traded companies with skin in the game already.

Company

What They're Developing

Boeing (NYSE: BA)
  • CST-100, a spacecraft that can deliver up to seven people to space stations in orbit.
Lockheed Martin (NYSE: LMT)
  • Orion Lite, in conjunction with private Bigelow Aerospace, would help deliver passengers to a commercial space station dubbed Sundancer.
Orbital Sciences (NYSE: ORB)
  • Cygnus, a capsule that can deliver cargo to a space station.    
  • Prometheus, a spaceship which will be the same as Cygnus, except that it will carry humans.             
  • Taurus I & II, which are launch vehicles (rockets) for space crafts.
Loral (Nasdaq: LORL)
  • Aquarius, a low-cost rocket carrier of supplies to those in space.

Is this a big deal?
Don't be misled; for behemoths like Lockheed and Boeing, this foray into space travel represents a drop in the bucket. And Loral is far more focused on its satellite business than it is Aquarius.

Orbital Sciences, however, is much smaller -- checking in with a market cap just above $1 billion. And though Orbital gets most of its money through contracts with NASA and the Defense Department, a breakthrough in space travel could move the needle far more for this company.

The Foolish bottom line
To those of you who are familiar with the industry, I'm probably stating the obvious. But for those of us who aren't rocket scientists, this represents a very interesting investing opportunity. Though it may not be feasible today -- or even tomorrow -- commercial space travel will likely be commonplace sometime in the future. The companies with their feet in the game earliest are usually the same firms best positioned to benefit from that trend once it reaches the mainstream.

I'm not saying we should go out and buy in right now. Rather, I think it's important for us to have fun following the stocks that we do. It makes us more likely to keep tabs on them and regularly re-evaluate our investment theses. Add these four companies to your watchlist today to keep up on the latest news.