August 25, 2012

Third Time Is NOT The Charm For NASA Launch

April Flowers for redOrbit.com — Your Universe Online

NASA was scheduled to launch the Radiation Belt Storm Probes at 4:07am EST, Saturday morning. Unfortunately, the launch was scrubbed for the third time and is now re-scheduled once again for 4:07am EST Sunday.

NASA's launch team has tried unsuccessfully to get the RBSP's off the launch pad twice this week already. The third time is not the charm for RBSP, it seems.

NASA had initially set the launch schedule for Thursday morning, but that appointment to send RBSP outside Earth's atmosphere was delayed due to "an anomalous engine condition," NASA said.

"An anomalous engine condition was identified during testing of another Atlas vehicle at the Factory in Decatur, Ala., and the delay will allow additional time for engineers to complete their assessments and verify that a similar condition does not exist on the RBSP launch vehicle engine," the space agency said in a statement following the initial delay.

The mission was re-scheduled to launch Friday at 4:07 a.m. eastern time from Space Launch Complex-41, however there was a slight delay at the last minute. The countdown was held at the T-4 minute mark because of an issue with the Air Force's Eastern Range beacon indications. The delay was not because of any technical issues with the spacecraft or the Atlas V rocket.

There was only a 20-minute window to make this launch in, making the go/no go decision very tense. The launch managers set the secondary launch time for 4:25 a.m., but were unable to make the window because the issue with the Eastern Range beacon indicators could not be resolved.

Launch managers rescheduled the third attempt at liftoff of the United Launch Alliance Atlas V/Radiation Belt Storm Probes mission from Cape Canaveral Air Force Station's Space Launch Complex-41 for 4:07 a.m. EDT Saturday at the start of a 20-minute launch window.

The decision followed a series of meetings to evaluate "out-of-family" readings in the signal of a C-Band tracking device linking the Atlas V rocket and ground-based range equipment that caused a scrub early Friday morning. The C-Band Transponder is one of several systems used to track the vehicle after launch for range safety purposes.

On NASA Television, NASA Launch Manager Tim Dunn explained that the C-Band tracking data issue that caused Friday´s launch scrub is acceptable for today´s launch attempt.

After the Friday scrub, the launch team spent hours analyzing the issue and reviewing data. They determined that a part on the C-Band transponder of the Atlas V rocket is performing slightly “out of family” compared to the way other hardware has performed in the past. Nevertheless, the U.S. Air 45th Space Wing Eastern Range is able to receive the C-Band signal and track it, so the condition is acceptable for flight. Additionally, to enhance vehicle-tracking coverage, the Eastern Range has added another radar tracker at the Jonathan Dickinson Missile Tracking Annex. This provides a slightly different angle and additional skin tracking of the Atlas rocket and gives the launch team added confidence during launch and ascent. Data from the C-Band transponder has been stable throughout today´s launch countdown.

The new concern Saturday morning was weather. At 2:42am EST, the weather watchers were giving only a 60% chance of acceptable conditions. At 3:35am, Launch Weather Officer Kathy Winters, of the 45th Weather Squadron, announced that there were thunderstorms with the potential for moving into the flight path and causing yet another delay.

"We haven't lost hope yet," said Winters.

At 4:23am EST, the launch managers called it quits because of dangerous weather conditions: lightning, cumulus clouds and attached anvil clouds. The mission was scrubbed once again, and the process of taking the rocket out of flight readiness was begun. As with the launch attempts on Thursday and Friday, there are no issues with either the Atlas V rocket or the RBSP spacecraft. The reasons for scrubbing all three times have been external.

Although the launch has been rescheduled once again, this time the Weather Squadron is only giving it a 40% chance of acceptable conditions, according to the launch blog.

The Atlas V that should have launched today has the job of placing almost 3,000 pounds worth of hardware into a carefully planned orbit. The RBSP spacecraft weigh more than 1,400 pounds each and are equipped with five identical instrument suites. The Atlas V, operated by the United Launch Alliance and managed by NASA's Launch Services Program, will life the spacecraft on the power of its RD-180 power plant, an engine that produces more than 860,000 pounds of thrust during the first stage burn. A Centaur upper stage with a single engine will take over after about four minutes, when the first stage has burned its fuel and oxygen. The Centaur employs a 22,300-pound thrust engine that will push the RBSP satellites into their proper orbits.

The two RBSP will have orbits that cover the entire radiation belt region, lapping each other several times during the course of the mission.

Once the probes are placed into their orbits, they will undergo a two-month "commissioning period," the time in which NASA engineers spend ensuring everything on the spacecraft are functioning properly.

"After you launch, after you get through the environments of launch and when you're up there in the space environment, you want to make sure everything's working perfectly," Mission Systems Engineer Jim Stratton said in a press release. "So that takes about 60 days after launch, and then we'll start our prime mission as soon as that commissioning period is done."

RBSP will help scientists improve the current models of how the radiation belts form and change, not only allowing NASA to help protect its spacecraft better, but its astronauts in orbit around Earth as well.

The Atlas V rocket has maintained its perfect record for now, launching spacecraft successfully on trips to Jupiter, Pluto, the sun, the moon, and Mars.