It is no coincidence that Space News’ Top 5 companies to watch have been in the news a lot lately. Any good story has a protagonist, a plot, tension that builds to a climax and some sort of resolution. For each of the companies, or protagonists, listed here there have been developments in the past year that portend substantial change — for better or worse — over the next year or two.

NASA and the changes in store for the U.S. human spaceflight program have been the biggest story for 2009 and so far for 2010, and this has profound implications for many companies. Two of the companies here — Space Exploration Technologies (SpaceX) and United Space Alliance (USA) — have their fortunes closely tied to decisions and events related to the human spaceflight program that will unfold over the next year or two. A third company, Orbital Sciences Corp., will be similarly affected, but to a lesser degree because that company is more diversified than SpaceX or USA. Orbital’s entry into the human spaceflight business is just one of several strategic initiatives under way that could in certain respects redefine the company, which has long been viewed as a provider of small satellites and rockets.

Meanwhile, the commercial satellite telecommunications industry has been dynamic as well, with export credit agencies such as Coface in France and the U.S. Export-Import Bank figuring heavily in the way companies get financing in a tough capital market and where they spend it. O3b Networks surprised many when it was able to secure substantial Coface backing for its proposed system. But the British company still has work to do in the coming months in terms of raising equity financing, securing customers and deploying its initial eight-satellite system. For Iridium, the question is whether it will be able to secure the necessary financing to get started this year on its next-generation constellation, which the company needs to begin launching in 2014 or risk a degradation of its existing mobile communications service.

As with many if not most lists of this sort, the selections were based on a combination of objective and subjective criteria; reasonable arguments could no doubt be made on behalf of numerous other companies that face substantial change in the coming months.

One final note: The order in which the companies appear on this list is random. The numbers assigned to each one should not be construed as a ranking, at least from Space News’ perspective.