It will be winter in Cambridge, but for passengers aboard the 757 jet chartered by Harvard's Museum of Natural History, the turn of the millennium will come in bright sunshine and it will come twice.

For $44,950, Harvard alumni can go on a transcontinental tour that will take them across the international dateline twice on a January 1, 2000, allowing them a second chance to celebrate the dawn of Y2K. The trip is sold out and promises to exhilarate.

In snowy Cambridge, however, the millennium--in popular parlance, if not technically accurate--may bring more headaches than thrills. The University, tied up in endless wiring and technology, faces a potentially disastrous start to the next millennium, as the so-called Y2K bug threatens the gadgets and infrastructure that keep the University running.

The glitch stems from computer chips and programs that take into account only the last two digits of the year in keeping track of the date. As a result, they recognize the year 2000 as 1900, and the difference could lead to severe problems for Harvard.

The scope of the disaster is potentially endless. Important machinery in University Health Services could shut down, registering that they had never been serviced. Payroll computers could malfunction, leaving Harvard's employees without their paychecks. Keycard locks on dormitories could electronically freeze. Temperature-controlled experiments could be disrupted and priceless specimens and research destroyed.

The University has responded by commissioning a team of Harvard computer programmers that has been working for months to avert disaster, reprogramming, testing and planning for the Y2K bug.

As a result, the most important computer systems at the University appear to be protected.

But with only months remaining until New Year's Day 2000, Harvard can only plan for the calamities other aspects of the problem could bring.

HIGH HURDLES

The most obvious problem with the Y2K glitch, it originally seemed, was with the important computerized records of the University--the "core financials," as administrators term them.

Those include budgets and human resource records. Money, after all, is key.

But according to Harvard Vice President for Finance Elizabeth C. "Beppie" Huidekoper, other concerns--particularly human safety--took precedence.

The Y2K bug posed myriad safety problems. For example, the computers used by the Harvard University Police Department were vulnerable to the glitch, as was the keycard system that is supposed to let Harvard students into their dorms and keep intruders out.

Animals in scientific laboratories were jeopardized. Hazardous materials that need to be deep-frozen looked to pose a safety threat if their cooling systems shut off.

The problem turned out to be so disparate, because of the independence of Harvard's separate schools, that Huidekoper likens it to "putting your arms around an octopus."