The former No. 2 executive of Intelsat pleaded guilty Friday to conspiracy to defraud the global satellite giant of $4.8 million.

U.S. District Judge Gerhard A. Gesell set Dec. 5 as the sentencing date for Jose L. Alegrett, former deputy director general of the International Telecommunications Satellite Organization, a consortium of 115 member countries that operates a network of telecommunications satellites.Alegrett faces a maximum penalty of 10 years in prison and a $250,000 fine or both.

Alegrett, fired from Intelsat in December 1986, was the fourth person to plead guilty in an intricate scheme involving unauthorized payments, bid-rigging, kickbacks and phony commissions in connection with the construction of the company's headquarters here.

Richard R. Colino, the former director general and chief executive of Intelsat, and two business associates pleaded guilty last year to fraud and conspiracy charges involving the embezzlement scheme.

Colino, who pleaded guilty to interstate transportation of money taken by fraud, is serving a six-year sentence. He also was ordered to pay $850,000 in restitution to Intelsat.

Charles C. Gerrell, a former Little Rock, Ark., mortgage broker, was given a two-year term and Manuel G. Serra, a Washington real estate broker, a three-year sentence. Gerrell and Serra pleaded guilty to conspiracy to transport money taken by fraud.