(Adds Gates quotes, analyst comment, background)
WASHINGTON Feb 2 (Reuters) - U.S. Defense Secretary Robert Gates said on Tuesday he did not expect a new bomber for the U.S. Air Force to be fielded until the late 2020s, a decade later than the previous Pentagon plan.
Gates said the Pentagon would study exactly what was needed in the new bomber before proceeding, including whether the bomber would be manned or unmanned, and would fly close to targets or stand off.
In the meantime, the Pentagon would upgrade its existing fleet of B-2 and B-52 bombers, he told the Senate Armed Services Committee.
"We're talking about a bomber that would probably not appear into the force until the late '20s," Gates told the Senate Armed Services Committee. "We're just trying to figure out, looking ahead a generation, what the right form -- what the right configuration for that would be."
Asked why the Pentagon needed to further study the issue after previous reviews, Gates told the committee that earlier work had examined whether to build a new bomber, while this review was focused on what exactly was needed.
Companies like Lockheed Martin Corp (LMT.N), Boeing Co (BA.N) and Northrop Grumman Corp (NOC.N) are hoping to bid for possible work on the new bomber, one of very few new weapons programs on the horizon at a time when the defense budget is expected to face mounting pressure.
The Pentagon's previous plans had called for a new bomber to be fielded in 2018.
Gates' new date indicates the program will get started and move into production nearly a decade later.
Gates told reporters on Monday that the Pentagon expected to spend "some $4 billion over the next 5 fiscal years for a number of long-range strike programs," including development of a new conventional bomber, and upgrades and modernization of the current bombers.
The Pentagon's fiscal 2011 budget includes $200 million for initial work on maturing technologies that could be used for a new bomber, and a total of $1.7 billion from 2011-2015.
Air Force officials said on Monday the initial funding in 2011 would help maintain the bomber industrial base as the military decided what exactly was needed to maintain the U.S. military's ability to hit long-range targets.
Defense analyst Loren Thompson of the Virginia-based Lexington Institute said the $1.7 billion would be focused on development of the new bomber, with the remaining funding referenced by Gates to be used for other long-range strike capabilities in the "family" of systems the Pentagon wants.
(Reporting by Andrea Shalal-Esa; Editing by Richard Chang)