Fwd: Delta 4 delayed by engine inquiry

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: October 19, 2013 12:19:34 PM CDT
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: Delta 4 delayed by engine inquiry

 

Engine tweaks delay Delta IV launch from Cape

Oct. 18, 2013 6:35 PM   |  

Written by

James Dean 

FLORIDA TODAY

 

Launch of a Delta IV rocket and Global Positioning System satellite from Cape Canaveral is on hold while United Launch Alliance studies adjustments made after an upper stage engine fuel leak during a launch a year ago.

 

The liftoff had been targeted for Wednesday from Cape Canaveral Air Force Station.

 

The analysis of the Aerojet Rocketdyne RL10B-2 engine will not impact NASA's planned Nov. 18 launch of the Maven Mars orbiter mission on ULA's Atlas V rocket, which uses a similar upper stage engine, the company said in a statement Friday.

 

The engine glitch occurred during the Oct. 4, 2012, launch of a Delta IV carrying another GPS satellite. The satellite successfully reached its intended orbit despite the upper stage producing less thrust than expected.

 

An investigation determined a fuel leak in the engine system was responsible.

 

Two more medium Delta IV rockets and one heavy version have launched since then, but ULA said continued investigation produced new information.

 

The delay will allow engineers time "to further assess these updated conclusions and assess the improvements already implemented and determine whether additional changes are required prior to the next Delta IV launch," ULA said.

 

The rocket has completed standard preparations at Launch Complex 37 and is ready to receive the GPS spacecraft and proceed with a launch attempt pending completion of the engine assessment "in the coming weeks."

 

Contact Dean at 321-242-3668 or jdean@floridatoday.com.

 

Copyright © 2013 www.floridatoday.com. All rights reserved.

 

 

                       

Next Delta 4 rocket grounded by RL10 engine inquiry

BY STEPHEN CLARK

SPACEFLIGHT NOW

October 18, 2013

 

United Launch Alliance has postponed the next launch of a Delta 4 rocket from Oct. 23 to sort out the significance of fresh conclusions stemming from an investigation into an RL10 engine anomaly during another Delta 4 launch one year ago, the company said in a statement Friday.

 

The launch company, which operates the Atlas and Delta rocket fleets, said it has not set a new date for the Delta 4 rocket's launch of the GPS 2F-5 spacecraft to replenish the U.S. Air Force's fleet of positioning, navigation and timing satellites.

 

Engineers are reviewing whether they need to make any changes to the rocket's RL10B-2 second stage engine. During a similar Delta 4 launch of another GPS satellite in October 2012, the RL10 engine sprung a fuel leak in flight, causing the engine to fire with lower thrust than planned.

 

The Delta 4 rocket compensated for the low thrust by extending the duration of all three of its second stage engine burns to achieve the mission's desired target orbit. The October 2012 launch successfully deployed the GPS 2F-3 satellite into the correct circular orbit with an altitude of 11,000 nautical miles.

 

The RL10B-2 engine is produced by Aerojet Rocketdyne. It generates a nominal thrust of 24,750 pounds, has an overall length of 13.6 feet, including 7 feet for its extendable nozzle, and a specific impulse of 465.5 seconds.

 

ULA and the Air Force gave the green light to resume Delta 4 launches this spring, with three successful flights occurring between May and August, lofting two Air Force Wideband Global SATCOM communications satellites and a top secret spy satellite for the National Reconnaissance Office.

 

The Atlas 5 rocket uses a different type of RL10 engine, and although it shares design features with the Delta 4's RL10B-2 engine, officials cleared the Atlas 5 to continue flying throughout the last year.

 

ULA said the upcoming Atlas 5 launch of NASA's Mars Atmosphere and Volatile Evolution, or MAVEN, mission remains on schedule for Nov. 18. MAVEN has a tight planetary launch window extending to mid-December.

 

Officials kept probing the root cause of the RL10 engine anomaly to avoid similar problems in the future.

 

"The ongoing Phase 2 investigation has included extremely detailed characterization and reconstructions of the instrumentation signatures obtained from the October 2012 launch and these have recently resulted in some updated conclusions related to dynamic responses that occurred on the engine system during the first engine start event," ULA said in a statement.

 

The company said the launch of the GPS 2F-5 satellite "is being delayed to allow the technical team time to further assess these updated conclusions and assess the improvements already implemented and determine whether additional changes are required prior to the next Delta 4 launch."

 

ULA said the Delta 4 rocket for the GPS 2F-5 mission has completed processing and checkout at the Complex 37B launch pad at Cape Canaveral Air Force Station, Fla.

 

The GPS 2F-5 spacecraft, built by Boeing Co., is also at Cape Canaveral awaiting delivery to the launch pad once investigators recommend corrective actions or exonerate the Delta 4's RL10 engine.

 

"A new launch date will be established when the assessment of the updated dynamic response information is completed in the coming weeks," the ULA statement said.

                                               

© 2012 Spaceflight Now Inc.