rose on Friday on what analysts say is investor enthusiasm for the company's widely anticipated commercial launch.

Iridium, a global satellite communications system, plans to begin service Sunday, after failing to deploy the system on September 23 as originally announced.

Salomon Smith Barney analyst John Coats noted that Iridium's stock price has been climbing all week. He said the stock had also benefited from an upgrade by Merrill Lynch & Co. analyst Thomas Watts, who raised the rating on the stock to near-term accumulate from near-term neutral. Watts rates the stock a long-term buy.

However, other analysts expressed scepticism about the company's business prospects and suggested that chief executive Edward Staiano's prediction of 500,000 customers by the end of 1999 was overly optimistic.

They pointed out that Bermuda-registered Iridium's call completion rate of around 90 percent was below the industry bench mark of 98 percent. Although the Iridium rate is expected to improve, the company could be making a tactical error by launching the service at below desired performance levels, some analysts said.

These critics also questioned the potential market for a $3,000 phone that, for instance, is valuable for someone on an oil rig in the Caspian Sea but not for callers who spend most of their time in major cities, where the phone must be converted to a cellular system.

Iridium's shares closed Friday at $47.50, up 9 percent, or $3.871 . The share price began the week at $36.25.