Ecco un’intervista sull’avanzamento del progetto dell’upper stage dell’Ares I:
Davis gives Ares I overview By Ross B Tierney, 9/4/2006 3:27:00 PM
Marshall Space Flight Center’s Danny Davis, manager of the Upper Stage of the new Ares I Crew Launch Vehicle, has given a fascinating inside overview of the vehicle that will transport Lockheed Martin’s Orion.
Below is part one of an ongoing Q and A with Davis - in which readers can ask their own questions.
Question: Could you please give us an outline of your role?
Davis: I manage the Ares I Upper Stage Element Office. The Upper Stage is an integral part of the Ares I launch vehicle that provides the second stage of flight for delivery of the Orion vehicle to low earth orbit.
My office is responsible for development of the stage requirements, stage design, verification of the design, fabrication and assembly, and support to operations at KSC. My role is to staff the management team that oversees all facets of the development process. As a team, we arrange for the appropriate engineering work force and budget to get the job done. We continually conduct assessment of the technical progress and risk management, and provide feedback to the ELO project office.
Question: What are your responsibilities?
Davis: I manage the NASA Design Team that is responsible for design of the stage. I develop the required budget and schedule to complete the project, determine risk to our success and report progress and issues to the ELO management. I am responsible for completing the mission within budget and on schedule. I am also responsible for the acquisition strategy to be used to purchase the need resources and products for the mission.
Question: What group(s) of people do you manage?
Davis: I manage the Element Office staff that sets the policy and plans for US development. I have a partnership with NASA Engineering at MSFC and other centers. The NASA Design Team is comprised of NASA engineering resources at NASA several Centers including their in-house support contractors. The NASA Design Team is formed into Integrated Product Teams that are allocated full responsibility for development of their specific subsystems. An example is the team we have established for Avionics and Software. The Avionics and Software IPT is responsible for developing all detailed avionics requirements, hardware and software design, testing and procurements and mission support to the flight systems.
We also plan to incorporate the Production Contractor in the IPTs early in the development process to ensure the NASA design is easy to manufacture and operate and to ultimately fabricate, check out and deliver the flight hardware. We plan on issuing a competitive RFP in early 2007 for our upperstage production partner and later in the year for our instrument unit production partner.
Question: Who do you report to?
Davis: I report to the Exploration Project Office at MSFC, directed by Steve Cook. ELO is part of the Constellation Program.
Question: What program(s) have you previously been involved with, and what was your area of responsibility in those?
Davis: I managed the RS-84 Prototype Engine Project where I had project management responsibilities similar to my current position. I have managed the Fastrac Engine project which was an in-house development of a 60K thrust LOX - RP-1 engine. These and other development experiences have provide valuable lesson learned for my current assignment.
Question: Can you please outline the current status of the overall Ares I development project?
Davis: The Ares I is working toward kicking off its systems requirements review in late October, 2006 - this will result in a set of validated requirements for the Ares I vehicle to which we will begin the preliminary design. The team was stood up in October, 2005 and has made remarkable progress which includes the following:
NASA team is up and running at several centers, including MSFC, GRC, LaRC, ARC, KSC, SSC and JSC
Completion of a 1st, full up design analysis cycle on all elements and the stack
Completion of over 1,400 wind tunnel test runs along with corresponding CFD analyses - including detailed models with protuberances, such as systems tunnels
Completion of an initial control systems design and validation using 6 DOF dispersed simulations
Development of a launch availability discrete event simulation - to help drive out costs and increase operability
Selection of ATK - Launch Systems as the 1st stage partner
Successful design and initial test of the new 1st stage pilot parachute at the Yuma Proving Ground
Baselining a common thrust trace for the Ares I 1st stage which will be also used for the Areas V
Fabrication of new 1st stage nozzle hardware
Fabrication of the new 1st stage forward section mockup
Selection of Pratt and Whitney Rocketdyne as the upperstage engine partner
Performance Risk Reduction Testing Initiated on the 40K injector rig for the J-2X engine
Completion of the J-2X engine preliminary requirements review
Demonstration of friction stir welding techniques applicable to circumferential welds on the upperstage
Completion of an initial manufacturing and logistics approach for the upperstage
Held an open house at the Michoud Assembly Facility to start to educate industry on the capabilities of this facility which will be used for upperstage assembly
Initiation of the Ares I-1 flight test. This will fly in 2009 and will inform the Ares I design in areas such as 1st stage flight dynamics, roll control, stage separation and stage recovery using new chutes and forward structures and vehicle operations processing at KSC
Question: What are the expected/target performance figures you are working towards achieving with the Ares I?
Davis: Our current requirement is to deliver the Orion to a -30x100 nmi injection orbit (at either 28.5 or 51.6ï¿½ inc). The performance capability is approximately 55klbm [Editors Note: approximately 25mT].
The Upper Stage
Question: Can you give us an idea of where you are in the current status of the Upper Stage (U/S) development program?
Mar 2006 DAC-1a - Design Analysis Cycle 1a
Jun 2006 DAC-1b
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Sep 2006 DAC-1c
Jan 2007 SRR - System Requirement Review
Mar 2007 DAC-2
Jun 2007 Contractor Selection
Sep 2007 SDR - System Definition Review
Dec 2007 DAC-3
Mar 2008 PDR - Preliminary Design Review
Jun 2008 DAC-4
Sep 2008 CDR - Critical Design Review
Dec 2008 DAC-5
Mar 2009 DCR - Design Certification Review
Davis: Our first priority is to develop requirements for the US design. Our System Requirements Review is scheduled for January 2007. This review approves all the requirements allocated to our stage and the flow-down requirements allocated to each subsystem IPT. To support requirement development we use conceptual designs of the US to show the feasibility of the requirements allocated.
This phase is going well. We have completed the initial Design and Analysis Cycle (DAC) and are confident that the US can meet all the current allocated requirements. We will use the current DAC to fine tune our approach. We have also initiated early development activities for selected long-lead components such as MPS Pre-valve, RCS Thrusters, and selected structural components. Our next step is to test the early develop test components to anchor the design and analysis models.
We have also initiated reliability, maintainability, availability and cost modeling that will be used by the design team to optimize the design - including cost as well as safety and performance.
The other design review dates are still under review, but these dates are reasonable approximations.
Question: Do you have a current specification of the Upper Stage as it stands today in this relatively early phase of the development program?
Davis: We have top level requirements that were based on validated conceptual design models. These have been found to be accurate for early allocation of requirements. Our engineering team is developing more rigorous design and analysis to support trade studies that optimize the US and the Ares I stack. Currently, US is confident we can meet allocated requirements. Allocations may change to optimize for low recurring cost and operability.
Question: Can you describe what are the next major elements of the development program which need to be tackled and give us an idea of where they fit in the above schedule?
Davis: We will continue to validate the feasibility of the allocated requirements and optimize the vehicle. Good requirements are critical to establish before detailed design begins. We will pursue limited advanced development projects to support the critical design phase with test data and analysis.
Question From NASASpaceflight.com member ‘Ed Kyle’: What, in your mind, is the long-pole of the tent, the toughest challenge, for both the U/S development, and also the overall Ares I development effort?
Davis: US intends to use Friction Stir Welding of Aluminum Lithium alloys for all major structures. We are working on welding dome gores and close-outs of circumferential welds. Early lab scale experiments have been very successful but the full scale hardware is the real proof. We are planning the fabrication and test of full scale components to support preliminary and critical design.
Other issues include ensuring the operability and low cost of our design. We are engaging the operators and industry partners early in the process to make sure we understand all lessons learned from Space Shuttle and recent expendable launch system developments. We have to optimize all feature of the Ares I vehicle to derive the best performance and operability.