The head of U.S. Strategic Command, Marine Corps Gen. James Cartwright, has said an array of prompt global strike weapons are needed to address urgent targets, such as terrorist hideouts or rogue nuclear capabilities that emerge suddenly and may prove fleeting.

In the near term, Pentagon leaders hope to modify the Navy’s Trident D-5 nuclear-tipped, submarine-launched missiles so they are able to deliver conventional payloads over long ranges and with improved accuracy. If the effort wins backing from a somewhat skeptical Congress, 24 of the modified missiles could be fielded aboard the stealthy subs beginning as early as 2009. Full capability could come two years later, according to Navy officials.

Meanwhile, Air Force Space Command is undertaking an “analysis of alternatives” to determine what technologies might prove most promising for a long-term prompt global strike capability, one that could be fielded by 2020.

In April, the command floated a proposal to develop a midterm system -- one that could bridge the gap between the near-term, modified Trident missile and the as-yet unspecified prompt global strike technology the Pentagon hopes to field in another 13 years.

Critics of the Trident plan say a midterm option might also serve as a hedge in case the Navy missile modification proves technically or politically infeasible.

The Air Force could initially field its midterm weapon system -- the so-called “Conventional Strike Missile” -- by 2013, officials said in April. It would likely use recycled boosters from decommissioned nuclear-tipped ICBMs, reconfigured so that the missile could only carry a conventional warhead. The system would be based separately from nuclear missile fields and could be inspected by other nuclear-weapons nations, officials have said.

This week, Chilton noted technologies developed under his command’s Common Aero Vehicle effort might also play a role in a midterm option for prompt global strike. Air Force officials envision CAV as riding atop a long-range missile into space and gliding back into the atmosphere at hypersonic speeds to destroy its target.

This technology may offer more maneuverability as it approaches a target than would more simple ballistic missile re-entry vehicles, thereby avoiding overflight concerns that bedevil other global strike solutions, according to officials and experts (see related story).

For CAV, as well as other technologies that might compete for a prompt global strike role in the midterm, Chilton has directed his staff to review what is readily available and requires little development time or resources, he said.

“I’ve asked, as we consider a prompt global strike capability: What are the technologies that we have on the shelf today?” Chilton said. He also asked the Space Command staff to estimate “the gap” between off-the-shelf technologies and those envisioned for the long-term strike solution, he said.

Are there “solutions that we can bring to the STRATCOM commander more in the midterm?” Chilton asked.

Cartwright is “looking kind of at the conventional Trident near term, [and] we’re looking at the high-end far term” in the analysis of alternatives, which began earlier this year, the air general noted. “Are there capabilities out there in the midterm that we can field without high technological risk in the development?”

Chilton said he initiated the review of midterm options but has full backing from Cartwright, the nation’s top strategic warfighter.

“I wouldn’t go off and do this without talking to him first,” Chilton said. “We’ve got such great expertise in the command, we can go off and look at other potential areas to leverage, to say, ‘Hey, we know what you’re asking for here. But maybe we can bring you something sooner that adequately meets your needs.’”

In seeking a potential midterm option, Chilton says he expects to achieve Cartwright’s requirements for a weapon that is responsive in its ability to hit a target within hours as opposed to days, has global range and operates transparently in its conventional capability.

He added that Cartwright envisions a system that could accommodate flexibility in the type of warhead it carries, to include area munitions for use against broadly dispersed targets, as well as point munitions for precise targeting.

“He doesn’t want to narrow in on it quite yet,” Chilton said of the warhead. Cartwright is looking for prompt global strike weapons concepts “broad enough so you can shape what it is that you put in there, so you can make those decisions later. We’re so early on here that you want to have preserved flexibility and options in your design at this [point],” Chilton said.