CAPE CANAVERAL, Fla. — A last-minute problem with a single actuator forced a postponement of SpaceX's attempt to launch a Falcon 9 launch vehicle carrying cargo to the International Space Station on Tuesday — and make a historic rocket landing in the process.
The landing experiment would have involved bringing the first stage of the two-stage rocket down onto a floating platform in the Atlantic Ocean, about 200 miles off the coast of Florida. Such a feat has never been done before. A successful maneuver would have marked a significant step toward making rockets more reusable and driving down the cost of spaceflight.
Even SpaceX recognized that the rocket stage landing, which was due to take place minutes after launch from Cape Canaveral Air Force Station in Florida, was not the mission's main objective.
"The main mission is absolutely to get cargo to the station, " Hans Koenigsmann, vice president of mission assurance at the California-based rocket company, told reporters during a pre-launch briefing at NASA's Kennedy Space Center.
Liftoff was aborted with less than a minute and a half left in the countdown. NASA commentator George Diller said the launch team identified a problem with actuator drift, affecting a control the second stage's rocket engine thrust.
"During the terminal count, engineers observed drift on one of the two thrust vector actuators on the second stage that would likely have caused an automatic abort, " SpaceX spokesman John Taylor said in a statement. "Engineers called a hold in order to take a closer look."
The next launch opportunity comes at 5:09 a.m. ET Friday, with NASA TV coverage beginning at 4:15 a.m. ET. Forecasters said there was a 70 percent chance of acceptable weather for launch.
Important supply run
This is SpaceX's fifth resupply mission under the terms of a $1.6 billion contract with NASA that covers 12 flights in all. The cargo run is particularly important in the wake of October's blow-up of Orbital Sciences Corp.'s Antares rocket, which was supposed to send a Cygnus cargo capsule to the space station. Some payloads have been shifted to SpaceX's Dragon to make up for that loss.
Among the more than 5, 200 pounds of supplies and equipment that have been packed aboard this Dragon are duplicates of 17 student experiments that were on the ill-fated Cygnus. The science payloads also include an experiment to study the immune systems of fruit flies and the wound-healing capabilities of flatworms in the space environment.
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