Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



Delta IV Heavy Launch Failure Investigation Continues

The Delta 4 Heavy clears the tower.
Los Angeles AFB CA (SPX) Jan 25, 2005
The Boeing Company and the Air Force continue to make solid progress in their investigation into the premature Main Engine Cut-Off (MECO) on the Delta IV Heavy Lift Vehicle (HLV) demonstration mission that was launched Dec. 21, 2004.

A Fault Tree analysis, which is used to categorize the potential root causes to include propulsion, avionics, and flight environments, etc., has begun. Forty of the forty-nine branches of the fault tree have been reviewed, ruled out as potential causes of the anomaly, and determined not to be a factor. These fault tree closures continue to clear the flight control systems (flight software and engine cut-off (ECO) sensors), the RS-68 main engine and the basic structure.   The leading cause of the anomaly remains a cavitation-type disturbance of the liquid oxygen flow that caused the liquid oxygen to change to gaseous oxygen. This disruption of the smooth flow of liquid oxygen from the propellant tank to the engine is caused by a unique combination of vehicle acceleration, liquid oxygen level in the propellant tank, tank pressures, and flow rates in the feedline when the RS-68 engine is at full power.

The engine cutoff sensors reacted to the cavitation, indicating a depletion of liquid oxygen propellant. In reality, there was adequate propellant in the tank to support the expected duration of the RS-68 engine burns.   Based upon progress to date, the combined Air Force and Boeing investigation team aims to complete the fault tree closeout and identify the cause by mid-February.

Additional testing to support computer simulations that analyze the liquid oxygen flow between the bottom of the propellant tank and the engine cutoff sensors through the feedline could continue through March.

Corrective actions will not be decided upon until the investigation identifies the cause.

"We're making great progress in working through our fault tree," said Dan Collins, vice president of Boeing Expendable Launch Systems. "Our Air Force and Boeing investigation team remains confident that we will identify the cause of the early MECO in a timely manner and determine an appropriate solution prior to our next scheduled Delta IV launch later this year."

A post-flight review of the complete HLV demonstration mission through payload separation is scheduled for late January. This formal review will evaluate all aspects of the mission to include achievement of the following significant test objectives:

- Activating and launching from the heavy version of the Delta IV launch pad

- Flying three common booster cores

- Separating the two strap-on common booster cores from the center booster core

- Flying the first 5-meter diameter composite payload fairing and separating it from the vehicle

- Flying the first 5-meter diameter cryogenic upper stage through a long duration, 3-burn profile of the RL10B-2 engine

"The investigation team is making solid progress in identifying the cause of the early engine shutdowns. The investment the Delta IV team made in additional telemetry has helped support the engineers as they narrow in on the cause of anomaly. I remain confident we will then be able to find solutions that allow us to avoid this problem on future flights," said Col John Insprucker, Evolved Expendable Launch Vehicle Program Director, Space and Missile Systems Center, and the Air Force mission director for the demonstration launch.

Related Links
Space & Missile Systems Center
Boeing
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express

Major Test Objectives Met Despite Botched Delta 4 Heavy Flight: Boeing
Cape Canaveral FL (SPX) Dec 22, 2004
The Boeing Company said Wednesday that the first flight of the Delta IV Heavy achieved the major test objectives despite placing its demonstration satellite in a lower than expected orbit.



Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only






Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.