Not to mince words, but the National Air and Space Museum is falling apart. The thin panels of Tennessee marble—actually, a kind of limestone—that clad the exterior are cracking and bowing away from its frame. The windows don’t block enough radiation from the sun. The heating and ventilation system has exceeded its intended lifespan. In addition to performing CPR on the building’s main components, the Smithsonian wants to make other upgrades, such as renovating exhibition galleries and redoing the large terraces around the museum.

To do it, Smithsonian Secretary David J. Skorton asked Congress last month for funding, a request that came as no surprise. The Smithsonian had announced a year before plans to overhaul D.C.’s most-visited museum, at a cost of $365 million. By March, that figure had risen to $581 million. But now it’s floating another price tag: $1 billion.

That’s right, for what it costs to buy the L.A. Lakers, the Smithsonian can resuscitate a 40-year-old museum.

Air and Space is the most popular museum in Washington, with 7 million visitors each year flocking to see The Spirit of St. Louis and the Apollo 11 capsule. But the building itself is not an architectural draw. Its main virtue is that it blends into its surroundings, a warehouse in the polite guise of an art gallery. The original design by Gyo Obata was severely compromised during construction, under pressure from the government to meet a tight budget and finish for the 1976 Bicentennial.

The building opened on July 1, 1976, at a cost of $41 million—but the real costs, it turned out, came later. The window walls that are failing today are only 15 years old, replacements in need of further replacement. The skylights are also again being replaced. At the time of their first replacement in 2001, one of the architects said “you could write a dissertation” on their problems.

The Smithsonian should consider demolishing the building and starting over.

That may sound sacrilegious. Americans are (thankfully) not in the habit of tearing down museums, especially museums on the National Mall. But $1 billion is an extraordinary amount of money for a brand-new museum, let alone a renovation. The National Museum for African-American History and Culture, set to open Sept. 24, cost half that, and it was built from scratch. The Smithsonian intends to raise private funds to cover the cost of new exhibition galleries, but it wants taxpayers to foot the bill for $726 million in repairs and temporary artifact storage. Construction would account for most of the total cost, at $578 million.

Credit: Darrow Montgomery

When asked about the possibility of razing the museum and rebuilding it, Skorton told House committee members that it would cost substantially more than $1 billion. A Smithsonian spokesperson says in an email that the cost of removing and conserving the exhibits alone would be “enormous.” Under a phased renovation plan, the museum will stay half open through the several-year project, and many artifacts will remain in place. The Smithsonian “is not interested in closing one of its iconic museums—supported with taxpayer dollars—to the public,” the spokesperson writes. For that reason, the cost of demolition and rebuilding was “not fully investigate[d].”

The potential cost of demolition and moving and storing all the exhibits is hard to guess. Whatever the expense, it’s understandable that the Smithsonian doesn’t want to go that route. Air and Space is the fifth most-visited museum in the world, generating millions of dollars every year from IMAX tickets and food and gift-shop sales. Closing it for a long period would kill revenue and badly disappoint members of the public.

If only there were a spillover site, somewhere people could get their aviation fix while the museum on the Mall was being rebuilt…

Unlike any other museum in D.C., Air and Space has a backup ready and waiting. It’s the Steven F. Udvar-Hazy Center, an annex near Dulles Airport that opened in 2003 and was expanded in 2010. A massive, straight-up hangar, it’s actually better suited to the purpose of exhibiting airplanes and spacecraft than the museum downtown. Udvar-Hazy is vast enough to fit the Space Shuttle Discovery and a Concorde, lets you watch aircraft conservators at work, and includes the usual revenue-generating arms (a gift shop, an IMAX theater).

Rerouting the Mall’s Air and Space visitors to Chantilly, Virginia, would be problematic. Chantilly is 30 miles from D.C. and not easy to reach on public transit. But it will be much easier when the Dulles station on Metro’s new Silver Line opens a few years from now.

Credit: Darrow Montgomery

Between now and the early 2020s, the Smithsonian could commission a new design, run it through the gauntlet of federal approvals, and start raising money. When the Dulles Metro opens, it could take down the current museum and direct visitors to Udvar-Hazy, offering free shuttles from Dulles. A few key exhibits from the old Air and Space could be moved for a time to the National Museum of American History, the Castle, or elsewhere on the Mall for those who can’t make the trek to Virginia.

The Smithsonian ruled this out (if it ever entertained the idea) and has hired local architecture firm Quinn Evans for the mega-renovation project. Design work is only 35 percent complete, but early plans are encouraging. The architects will add vestibules to the entrances to handle long queues, and top these with broad, gently swooping new canopies for sun and rain protection. They’ll revamp the drab terraces outside, removing awkward half-walls and planting trees. More than a thousand solar panels will be placed on the roof to meet sustainability goals. Given the budget, they’d better get that LEED Gold certification.

The new-old hybrid that results should be a big improvement on the creaky original. Some Modernist era landmarks, like New York’s Lever House, have gone through very exhaustive renovations and emerged the better for it.

But Air and Space isn’t up to that standard. It doesn’t have an important place in architectural history, and its form and details aren’t memorable. In general, adaptive reuse is a smart and resource-wise strategy, but there’s a point when so much of the original fabric gets stripped away that the environmental benefit is lost. The museum’s damaged Tennessee marble cladding can’t be reused, and neither can the glazing from 2001.

Hewing to the old design closes off other options. A new design could incorporate cutting-edge building science, in keeping with the technological innovation that the museum celebrates. It also might excite donors enough to get them to cover much of the cost, as at NMAAHC, which was 50 percent privately funded.

In his statement to House members, Skorton stressed the scope of the renovation and said it will see the building through the next 100 years: “In essence, we are creating a new Air and Space Museum for the American public.”

Well, sort of. It will be a re-engineered version of the old one with some (nice) new touches. The Smithsonian’s backlog of deferred maintenance is daunting, and the political optics of a do-over are bad—“demolish and replace” is always going to sound more extreme than “make essential upgrades,” however the costs might compare. This was the less risky decision. But it’s disappointing to be spending $1 billion patching up an old workhorse rather than creating something that would surpass it.