By Chibuike Oguh

NEW YORK Shares in Viasat plunged by as much as 36% to about a one-year low on Thursday after the U.S. satellite communications firm disclosed that one of its key satellites malfunctioned during deployment in space.

The company's ViaSat-3 Americas satellite developed an unexpected fault during its deployment - an issue that might affect its performance, Viasat announced after markets closed on Wednesday, adding that it had launched a review.

The satellite, which was launched onboard SpaceX's Falcon Heavy rocket on April 30, is a key part of Viasat's plan to expand its broadband business in the Americas.

Viasat's shares were off 28.5% at $30.73 on the session in early afternoon trading. The stock was on course for its biggest one-day percentage decline on record, surpassing a 27.7% drop in April 2001, per Refinitiv data.

California-based Viasat provides Internet connectivity to homes, commercial and private aviation, and the defense industry. The company said it is working to minimize the economic impact of the faulty satellite by redeploying other satellites from its fleet.

Viasat in May completed its $7.3 billion acquisition of British satellite rival Inmarsat after securing approval from European Union regulators. Viasat owns and operates four geostationary earth orbit satellites while Inmarsat has 15.

(Reporting by Chibuike Oguh in New York; Editing by Will Dunham)