Marco Caceres, a space analyst with the Teal Group, called the CSM change a "win-win" for both sides.

"Every time you cooperate, every time you fulfill or submit a request, that is how you build relationships," Caceres said. "Particularly if the US is coming to see China as their next military rival in space, and they are doing an awful lot and spending a lot more money on both military and non-military space, potentially [this new agreement] could be significant because it strengthens the relationship."

"I don't see how Orbital, given all the negative publicity around Russian engines, could go with another Russian engine," says Marco Caceres, space industry analyst for aerospace and defense consultancy Teal Group. "How could the CEO explain another accident to shareholders? I think you have to go with a red, white, and blue company."

But finding that company could prove daunting. Aerojet Rocketdyne's existing production line produces powerful engines for the Delta IV and NASA's new super-heavy-lifting Space Launch System—likely too much engine for Orbital's medium-sized Antares rocket, Caceres says. 

The agency doesn't yet have a rocket powerful enough to blast it into space that is also deemed safe enough to transport people. "It's kind of like sitting in a beautiful Cadillac, without an engine or tires," said Marco Caceres, director of space studies for Teal Group, a Fairfax, Virginia-based consultant.

The cost of the SLS and Orion could grow to more than $30 billion, said Marco Caceres, a senior space analyst with the Teal Group consulting firm. There is a fair amount of opposition to the asteroid mission in Congress, and a Mars landing, some 20 years away at best, remains a dream.

"To make matters worse," Caceres wrote in a recent blog, "is the painful fact that the rocket doesn't actually have a mission."

The Mars program is subject to funding constraints and a balky political system.

"This is the problem with anything that takes 20 years — people have very short attention spans," Caceres said. "And you have numerous presidential administrations and Congresses, and inevitably someone gets around to canceling it, or reducing it."