Amid the backhoes and cranes on the East Front, far below the skylights which will eventually illuminate the Capitol Visitor Center, 170,000 square feet of Congressional real estate awaits its future occupants.

Flanking both sides of the CVC will be almost 85,000 square feet of much-needed additional office space for each chamber. Much of the $70 million space — set to be completed in fall 2006, a few months after the visitor center opens its doors — has already been designed and allocated. Bids for the construction are due out this fall.

Senate Rules and Administration Chairman Trent Lott (R-Miss.) recently disclosed that the Senate will use the first significant new Capitol real estate in two decades for an expanded and updated recording studio, additional meeting rooms and new space for the Office of Senate Security, which is run by the Secretary of the Senate and handles classified material for the chamber.

The space will also house climate-controlled storage facilities for the Senate gift shop and the curator’s office, both of which currently have to go off-campus to store sensitive artwork and other items, a senior official said. The Senate’s closed-captioning service, a division of the Secretary’s office, will also move to the subterranean space.

Construction of the CVC’s underground truck tunnel eliminated the recording studio’s previous location. The Office of Senate Security is currently located in Room S-407.

Lott indicated that at least one of the new meeting rooms in the Senate’s “shell” space, as it is called, will be comparable to the Mansfield and Lyndon Baines Johnson rooms, where the parties hold their weekly luncheons.

“We have a real problem around here: We need more meeting space,” Lott said, adding that he has put his hideaway into the mix because meeting space is so scarce.

Plans currently call for five new general-purpose meeting rooms, to be used by Senators visiting with residents of their states, among other purposes. “The primary emphasis is on the constituent meeting room space,” the senior official said.

But because the CVC is likely the last major addition to the Capitol, a significant portion of the new space also will remain unoccupied to allow for future needs.

“I think there is some space that has not been clarified for a reason,” Lott said. “We’ve got it designed where there will be some more available space, but it’s not now earmarked.”

To Hill denizens, un-earmarked Capitol real estate usually translates into two words: land rush.

But Senate aides said that jockeying for the currently unassigned space has not begun in earnest, at least in part because the new facility is two years away from being occupied. “We’re not arranging the chairs,” the official said. “All of these designs are still being refined.”

Beyond a vast new expanse of space for the Senate and House, a handful of rooms, primarily in the basement of the Capitol, that were lost during construction will again become inhabitable when the visitor center finally opens.

The Capitol Police are expected to move out of their not-especially-lovely but nonetheless coveted space in the basement as soon as they occupy their expansive new quarters in the CVC, which in turn should free up even more square footage. But in a sign of just how uncertain the landscape can be during this period of fluid office space, Rep. Jim Moran (D-Va.) last year chastened the Capitol Police at a hearing not to have designs on retaining that space while simultaneously occupying the 17,000-square-foot new command center in the CVC.

Lott has mentioned the basement space as possible quarters for more hideaways, at the same time dispelling any notion that the CVC will house sought-after private space for lawmakers.

For whatever reason, up until recently the Senate has been relatively tight-lipped about its plans for the shell space, especially vis-à-vis the House, which provided details of its designs — including who was going into the new facility and what it would look like — almost two years ago.

One Senate aide whose office will likely be affected by migrations to the CVC said the Rules Committee has persistently avoided questions about who would be affected and how.

“They have been very secretive about it,” the aide said.

A Senate source familiar with the process said, “We definitely have plans laid out and have had them laid out for quite a while. I think we’ve even got some of the details worked out, [such as] carpet colors.”

Indeed, the blueprints are nearly final, having been crafted over the past two years in coordination with RTKL Associates, the firm handling the architectural plans for the entire visitor center.

“Right now we have all the designs from the House and the Senate,” said CVC spokesman Tom Fontana, adding that 95 percent of the documents are in a final or near-final stage. The blueprints recently were set to go back to the House and Senate “for one last look-over.”

“It’s a constant refinement process,” Fontana said. “As they block out the space, it gives a chance for the House and Senate leadership to say, ‘It might work better this way.’”

Requests for proposals won’t go out until the fall, because construction going on within the CVC itself will preclude work from beginning on the expansion space. While major construction continues on the main facility, the area eventually to become the expansion space will be used for temporary egress, fire and emergency access, and staging of materials, Fontana said.

Overall, both Senate and House officials hope the new space — which in square footage is the near equivalent to the footprint of the Capitol building, or about 4 acres — will alleviate the space crunch that has plagued the campus for years. For example, the officials hope to decrease the current dependence on Room HC-5 in the Capitol and the Cannon and Russell caucus rooms for large gatherings.

As for the House’s expansion space, plans include a large hearing room that will be second only in size to the Ways and Means Committee hearing room. The 3,500-square-foot, state-of-the-art room is designed to accommodate up to 60 Members and will feature plentiful public seating, making it ideal for conference committees and joint-chamber hearings.

New space for the House Intelligence Committee on the bottom floor will be equipped to support secured briefings and provide additional conference rooms for staff. The panel currently operates out of a cramped area on the fourth floor of the Capitol. In addition, the 450-seat Congressional auditorium in the central portion of the visitor center will meet heightened security standards, so that the House floor — which doesn’t meet those requirements — will no longer have to be used for chamberwide intelligence briefings. (Senators meet in Room S-407 for secure briefings.)

Additional studio space for the House Radio-TV Gallery will be located on the top floor. The space will give the gallery larger studios for press conferences and one-on-one interviews. Officials hope to have enough space to accommodate two press conferences simultaneously, as well as maintain use of the current studio space in the Capitol.