By Paul Recer Associated Press HOUSTON — Officials of a Houston company say they plan to launch a rocket on a suborbital flight next week. Donald K. Slayton, the former astronaut who is mission director for Space Services Inc., said the rocket is on a launch pad at Matagorda Island on the Texas Gulf Coast and will be ready to blast off at 10 a.m. next Wednesday. He said he was ‘about 99.4 percent’’ sure the rocket would fly as planned. “We're confident it’s going to work like a charm,” Slayton said Wednesday. Named Conestoga I, the rocket is a solid-fuel second stage of a Minuteman I missile. In a 1042-minute flight, the rocket is to carry a dummy payload far above the Earth and spew out a shower of ice crystals. It then is expected to fall into the Gulf of Mexico. Space Services Inc. paid the National Aeronautics and Space Administration $365,000 for the rocket. The total cost for the launch is about $2.5 million, company officials said. David Hannah, chairman of Space Services, said the success of the launch is critical for the company because of a fiery failure last year. “We've got to see whether we can do it, he said. A liquid-fuel rocket exploded spectacularly in August 1981 during a pre-launch engine test on Matagorda Island. A kerosene- and liquid oxygen-fueled fireball enveloped the pad and soared 200 feet. There were no injuries, but it set back SSI by six months and led it to select another engineering team and a different rocket. Eighty seconds into the Conestoga’s flight, a shroud covering the payload will be separated by small rocket thrusters and the rocket booster will burn for an addi tional five seconds. Then the booster will fall away and other rocket thrusters will send the 1,097-pound payload into a spin. Four hundred pounds of water, carried for ballast, will be ejected from the craft at its highest point above the Earth. Slayton said the water will turn into a shower of ice crystals. The craft is expected to splash into the Gulf of Mexico about 259 miles from the Texas coast.