"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. 

This is not the first time the Russian-made AJ26 engines have caused problems, Marco Caceres, an analyst at Teal Group Corp., wrote in an Oct. 31 note. In 2007, the Sea Launch Zenit 3SL exploded because of an engine clogging and SpaceX failed to launch its Falcon 1 in March 2006 due to engine failure, he wrote.

If the engine proves to have been at fault in the latest explosion, it would be easier for Orbital to replace them rather than to attempt a repair, Caceres said in a phone interview today. "Their confidence in the engine was never high," he said.

NASA is "looking for cheaper access to space," said Marco A. Caceres, a space analyst at the Teal Group, a consulting firm in Virginia. The trouble, he said, is that reliability and price are often tied together.

"It may be unreasonable to expect to pay under a certain amount to get a reliable vehicle," Mr. Caceres said. "That comes at a cost."

Marco Caceres, the director of space studies for the Teal Group, an aerospace industry analysis firm, predicted Wednesday that the launch failure would inevitably lead to "Monday morning quarterbacking" from "people within Congress and the space industry who continue to believe that NASA should continue to own, manage and operate its own launch vehicle instead of leasing launch services from private companies."

But, Caceres said in an e-mail: "The reality is that catastrophic launch failures like the one we saw yesterday have little to do with whether it's a private company managing things or NASA. NASA has had its share of horrendous failures — both in terms of launch vehicles and satellites. The idea that the government is inherently better suited for spaceflight is a myth."

NASA's shift to leasing services rather than owning its own rockets as part of its human-spaceflight program has been "a bold move and certainly risky in some ways – primarily because you're changing the paradigm," says Marco Caceres, senior space analyst and director of space studies for the Teal Group Corp., an aerospace-research firm based in Fairfax., Va.

The move has been driven in no small part by an agency asked to do more than either presidents or Congress were willing to pay for, especially when thinking about eventual replacements for the space shuttles.

Tighter budgets, cost overruns, and the agency's reputation for overestimating the amount of money the space shuttles would save in operating costs because they were reusable didn't help, Mr. Caceres suggests.