During the two years that David C. Lucien was president and chief executive of Tempest Technologies Inc., he led an exhausting struggle to shore up the company's nose-diving sales, trim its excess fat and return the Herndon computer company to profitability.

Yesterday, the 40-year-old Lucien announced at a shareholders meeting that he was quitting.

"I really felt I had reached a point in my career that it was time to look at other options, whether starting a new company or buying a company or going to run another one," Lucien said in an interview.

"I spent countless hours with my family and with the board arriving at the decision," Lucien said. Board members were told of his plans about five days ago, he said, but the announcement was delayed until yesterday because the company was trying to convince him to stay.

Lucien said he would like to work outside the market that Tempest is in -- modifying computers to protect against electronic surveillance.

Over the last two years, cutbacks in defense spending and a number of stricter government standards have caused this market to plummet, forcing a number of companies to drop out of the business.

Although Tempest, which is majority owned by another Herndon-based firm, C3 Inc., decided to fight it out, its sales and earnings suffered. In the last two years, revenue skidded about 70 percent, from $26 million in 1988 to $8.1 million in the year ended March 31. The firm had losses of $1.3 million in the latest year compared with a profit of $316,000 in fiscal 1989.

The trend is continuing this year, with the company earning $4,000 on revenue of $2.1 million for the three months ended June 30, compared with $231,000 on revenue of $2.7 million for the same period last year.

In an attempt to reverse the declines in sales and earnings, Lucien reorganized the company and developed new product lines. He also reduced labor costs by about 18 percent through layoffs and attrition. The labor force shrank from a high of about 90 employees to about 65.

"These have been trying times," said company Treasurer Alan Stewart, referring to the business conditions and the layoffs and cutbacks Lucien has made. "After he made these actions, I think he thought: 'Now is the time to step out and try other things.' " Stewart added that he was surprised by Lucien's resignation.

Lucien will remain on the company's board of directors and continue as president until Oct. 15 to give the firm time to find a replacement.

Stewart said the board, which met yesterday, will appoint an executive search committee to hunt for a new president. Lucien, who made $160,910 in salary and compensation last year, will assist in that effort.

Lucien joined Tempest in 1983, two years after it had been founded. He served as vice president of marketing and sales until June 1988, when he was appointed president and chief executive officer. Before joining Tempest, he had been manager of federal business development at Intel Corp.