New engine configuration under evaluation for Ares V – PTV fails

by Chris Bergin

The Ares V core stage team is currently evaluating a configuration change to the location of the six RS-68 main engines on the ever-growing Ares V. External engine fairings – similar to the Saturn V first stage – are being considered, in order to configure the six RS-68 engines away from the Solid Rocket Booster exhaust.

Meanwhile, the Orion Parachute Test Vehicle (PTV) has been destroyed during a test failure late this week.

**The most comprehensive collection of Shuttle, Ares, Orion and ISS related presentations and mission documentation, plus expansive daily processing documentation and updates are available to download on L2 **

All of this article is based on documented L2 information. For an overview of how L2 works, **click here for sample video**


**ORION/Exploration Vehicles LIVE UPDATE PAGES**



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Ares V:

The ‘Alternate Engine Arrangement’ presentation – dated July 29, 08 – notes the Ares V team have been tasked with mitigating the issue of plume impingement, caused when the exhaust plume of one engine interferes with the plume of other engines in the cluster, thus reducing the efficiency of all the engines.

Also, due to the RS-68 being an ablatively cooled engine – with the nozzle ablating only from the inside – heating from the SRB could cause the nozzle to be abraded from the outside.

Ares V needs at least six RS-68 engines to close the performance gap, and must therefore attempt to create additional space on the core by placing the engines a set distance away from each other.

The proposed configuration results in two groups of three engines arranged in a triangle. Two of the engines in each triangle are spaced around the peripheral of the core stage and housed completely in a new aerodynamic fairing.

The ‘internal’ engine in each triangle is mounted on two thrust beams spanning the bottom of the hydrogen tank.

On the downside, such a reconfiguration will add weight, and more importantly, it will increase drag on the vehicle by a large percentage – both impacting on performance.

Other concerns with the core stage references sub-system growth – especially in the thrust structure and Main Propulsion System (MPS), and the need to place baffles into the tanks to control the internal shifting/sloshing of propellant, to avoid controllability issues.

‘Potential weight growth: thermal protection from extreme base heating: radiation, plume recirculation, fuel rich GG exhaust burning, aero-forces on engine nozzle and structure, potential need for fairings (increased drag),’ listed the presentation, acquired by L2, on the main challenges the Ares V core team are working on.

‘SRB sep motor plume impingement, sub-systems growth: thrust structure, MPS, avionics, power.

‘Propellant load: volume removed for slosh and anti-vortex baffles propellant conditions need further definition (temp, pressure, density at various points). Ullage volume low for this stage of study.’

Other issues with the RS-68 is the burn time of 303 seconds at 108 percent of rated performance, a situation for which the current motor has not been qualified for.

Documentation also notes the requirement of using large quantities of helium – and the challenges of packaging it on the vehicle – along with routing the propellant feed lines to the final engine configuration.

An engineering solution to eliminate the Delta IV ‘fireball’ effect – in which unburned hydrogen is ignited as the engine powers up – is also required.

‘RS-68 Engine: Burning for 303 seconds at 108 percent power level – uses large quantities of helium (packaging),’ added the issues/concerns, ‘large quantity of free hydrogen in GG exhaust, engine thrust post attachment location/thrust structure, propellant feed-line routing.’

The recent change to the 5.5 segment boosters on the core stage is also causing fallout, with a need to minimize thrust imbalances also noted. The resulting local spikes in base heating and RS-68 thrust impingement will require further analysis.

The thrust imbalance concern is in relation to the natural thrust variation between the boosters as they grow in size – as seen with the recent move to 5.5 segment boosters. A thrust mismatch can affect the flight path of the vehicle.

‘5.5 segment SRB’s: thrust imbalance – local spikes in base heating, potential increase RS-68 cosine performance losses, operational impact (thrust matching stages),’ the issues/concerns list continued.

Ares V Ground Support:

It’s still early days in the development of the mammoth Ares V, with further configuration changes not ruled out – especially based on gaining performance. The largest ‘viable’ Ares V to be noted is ‘Ares V Max’ – which consists of seven RS-68s and two 6.5 segment boosters.

Even taller variants have also been documented, but all are too tall to fit inside the Vehicle Assembly Building (VAB), and are classed as requiring a new giant Vehicle Integration Building (VIB) to be built – which would not be viable on associated costs.

With the current Ares V, documentation on the current status also listed ground support concerns, referencing conflicting GSE (Ground Support Equipment) facility needs, as the Ares I and Ares V designs diverge.

Also listed are concerns with new manufacturing and test facilities, new transport barges, new ‘super’ crawlers, a specialized launch prep crew, and a different launch control center – all required by Ares V.

Facilities: conflicting facility needs with Ares I – manufacturing and test, assembly and transport, crawler, launch prep crew, launch control center,’ added the Issues/Risks/Concerns on the current status, ‘new transportation barge(s), test facility modifications, MAF (Michoud Assembly Facility) modifications.’

Also, should the configuration change to the location of the RS-68s be approved, new design work will be required on the Mobile Launch Platform (MLP).

Orion Parachute Test Vehicle:

The Orion Parachute Test Vehicle (PTV), a truncated looking Orion, has suffered a failure, after it became inverted following extraction from a C-17 aircraft.

The vehicle – which flipped upside down – was unable to properly deploy its parachutes, resulting in them being ripped off the vehicle, before it crashed to Earth, causing a large crater in the ground.

An investigation is taking place into the failure at the US Army Yuma Proving Ground on Thursday.

The extraction methord – which utilizes a sledge or pallet to deploy the PTV out of the back of the C-17 – was recovered via its own parachute system. It is not currently believed to be the cause of the mishap.

The previous drop test that failed was back in early 2007, when a Drop Test Vehicle (DTV) with an Ares I pilot parachute suffered a fault with the riser connecting the parachute to the DTV.

The vehicle – dropped from a C-130 at 17000 feet – was destroyed, with parts of the DTV needing to be extracted from depths of up to 30 feet below the surface.

More will follow on the PTV failure when further information is available.

Selection of L2 Resources For Ares I, V and Constellation: 

Ares V Alternative Engine Arrangement Presentation. Hi Res CxP Logos. Full (and very expansive) set of presentations on Ares/Orion mass and status report. Ares I ‘Parasorber’ TO migitation hardware presentation and animation. Ares I TO Risk Slides. Ares I Risk Status.

Hi Res Images of Ares I FS Parachute Test Vehicle (JDTV). 20mb of new Lunar Images of Chariot, Athlete and Lunar Crane. Ares I KSC Processing Master Book – 184 pages. Changes for Ares I-X (Images). PRCB Transition Presentation (Shuttle to Ares). Ares V (5.5/6xRS-68) Presentation (and more). Orion Parachute Vehicle Images. Latest Risk Matrix for Ares. SI Unit Directive Document. CxP PMR08 Manifest. PDR and associated notes from CPCB meeting. Orion Parachute Test Vehicle (PTV) Photographs.

110mb worth of Ares I-X Weekly Test Presentations (Ares I-X, J2-X etc. up to end of April) The Orion LIDS (Low Impact Docking System) Section (Images, Videos, Engineering Notes). Hi Res Images of Ares I in the VAB. Ares I-X Integrated Milestone Charts. Ares I Thrust Oscillation Focus Team Status Presentations (over 50mb – includes DTO on Shuttle missions), Ares I-X Global Buckling Status Presentation, Ares I – Launch Pad Stabilization and Damping Presentation, Ares I: Purge/Vent/Drain and Vehicle Access Presentation.

Ares Tilt Up Umbilical Arm (TUUA) Test – Video, Ares/Orion Comm and Tracking Presentation, Ares I Nozzle Extension Update Presentation, Ares/Orion Integrated Stack TIM Summary (Major Issues) Presentation, Orion Land vs Water Landing Update + Crew Survival (post 36 hrs) Presentations.

Altair Overview Presentation. Ares I Risks and Status. Ares I-X Booster Recovery Images and Video. Ares I-X Pad Images. Ares I-Y Mission Overview Video (50mb – Superb).  Orion Lunar Transit CGI Video. (Several more videos, including first video of Orion splashdown). 

Orion Rendezvous with the ISS CGI Video, plus AERCam Inspections. Ares I Thurst Oscillation Update Section.  Images of completed PA-1 boilerplate Command Module at LaRC.  CxP Planning for Architecture Closure – Feb 19. Ares V Overview Presentations. Other Major CxP Updates for Feb (List restricted to L2).

Orion 607 Overview Presentation (Jan 08), Constellation Program Status/Budget and new Manifest to Orion 20 Presentation (Jan, 08). Michoud Transition to Ares I/V (Jan 17, 08). Several MLAS (Max Launch Abort System) Presentations. Over 60 Hi Res Images of Orion Mock-up at JSC (Hatch, Seats, Flight Deck) – December.

Lunar Habitat Assembly. PRCB Presentations on hardware and infrastruction transition (from Palmdale to MLP Park) ‘Follow live’ Lightning Towers Construction images. Latest Mobile Launcher details. Orion/Ares I/Delta IV Heavy NEO Feasibility Study (Video). Constellation EVA Study Presentation. Superb Gene Kranz address to CxP workforce (Apollo to Orion feature) video. MOD ‘LEO to Mars’ presentations.

Superb Ares I Launch Ascent, Pad Abort Test CGI Videos (three). Integrated Stack (IS) Technical Interchange Meeting (TIM) notes – Nov 6 to Nov 15. The full ‘8th Floor News’ – Constellation Update (performance issues) – Nov 5. Ares I Mobile Launcher PMR.

‘Proposed’ Ares I SRBSF (Mini VAB) and graphic. LSAM (LDAC-1) Video and Images. Several Constellation All Hands Videos and Presentations. Ares I Pad Rollercoaster (Old and New presentation and slides – the very cool ‘CGI ride on the Ares pad coaster’ video. Ares I VAB ‘In-Line’ Stacking presentation slides.

Presentation of Ares/Orion impacts relating to Shuttle manifest acceleration. Ares I Interstage diagrams. Ares V Super Crawler. Ares I Launch Pad images (ML etc.) Hi Res images of Ares I-X Upper Stage. Orion 606-7 Data Updates. Updates Constellation launch schedule through to Orion 15. Orion Seat test photos. New ML Graphic and info. New Ares V graphic and baseline data. Large collection of hi res Orion paracute drop tests. SIX Part Series of Ares I Upper Stage Graphical Overviews. DAC-1C DDD Vast Slides on Vehicle Design. ATK First Stage Presentation. 39B Lightning Towers Slides. DAC-1C Departure points to DAC-2 Upper Stage Graphcs (Many Changes).

Orion/CEV Display Layout Presentation (40 pages). ATK figures on the 5-Seg Booster weight for CLV. Weather Shield (Rain Shield) for Orion on the pad. New Super hi-res images of Ares I. ATK Cutaway graphics of Ares I – perspective and axonometric. Ares I/Orion CxP 72031 Requirements Validation Matrix Information. CEV Paracute Assembly System (CPAS) Presentation.

Orion Launch Abort System (LAS) overview presentation. Changes to Ares I Upper Stage – expansive details and data. Ares I/Orion CxP 72031 Requirements Validation Matrix Information. CLV Umbilical Trade Matrix XLS. Vehicle interfaces for the DAC 1C version of Orion Ares. Ares I-X Test Flight Plan (full outline) Presentation. Ares I-X timeline and modification expanded info. Ares I Reference Trajectory. Boeing’s STS to Ares – Lessons Learned Presentation. CLV DAC-1C (Changes to CLV Upper Stage).

Ares I-X: Four Seg+Dummy ‘Tuna Can’ stage. Ascent Developmental Flight Test Presentation. CLV Pad 39B Handover Info and Latest. New images of CLV on top of new MLP and LUT. Lockheed Martin CEV/Orion Updates. ATK figures on the 5-Seg Booster weight for CLV.

90 Minute Video of Constellation all hands meeting. Escape System Trade Study Presentation. CEV-CLV Design Analysis Cycle Review (DAC-2) Presentation. Flight Design and Dynamics Division CEV update. CLV Mono-propellant RCS system. CEV pressurisation system review. CLV/CEV Configuration Images. The 2×3 Seg SRB Crew Launch Vehicle Option Presentation…

….plus much more (L2 Constellation over 195,000mb in size).

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