WASHINGTON — A boat that entered restricted waters forced Orbital Sciences Corp. to postpone the launch of a Cygnus cargo spacecraft Oct. 27.

The launch of the Antares rocket, scheduled for 6:45 pm EDT, was scrubbed when a sailboat entered a restricted zone off the coast from the launch site at the Mid-Atlantic Regional Spaceport at Wallops Island, Virginia. The boat was not able to leave the zone before the ten-minute launch window closed.

There were no technical issues reported with the Antares rocket or the Cygnus spacecraft prior to the scrub, and weather conditions were favorable. Orbital Sciences and NASA announced the next launch attempt would be Oct. 28 at 6:22 pm EDT. Forecasts call for a 95 percent chance of acceptable weather at the new launch time.

The mission, designated Orb-3 by NASA, is the third of eight Commercial Resupply Services missions that Orbital Sciences is under contract to perform for the space agency. The Cygnus, named by Orbital the “SS Deke Slayton” after the late astronaut, is carrying 2,290 kilograms of cargo for the station.

That cargo includes a number of small satellites that will later be released from international space station. Those satellites include 26 from Earth imaging company Planet Labs and a technology demonstration satellite developed by asteroid mining company Planetary Resources.

The launch is also the first Antares mission to use the Castor 30XL motor for the upper stage. The motor, an extended version of the Castor 30B solid-propellant motor previously used by the Antares, will allow the vehicle to carry additional cargo on future Cygnus missions.

Despite the launch delay, the Cygnus is still scheduled to arrive at the ISS early Nov. 2.

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