Ares progress update – opening J-2X engine tests completed

by David Harris

As the Constellation Program prepare to update the media on the current status of Ares and Orion next week, L2 has acquired an expansive synopsis of the current data on the new vehicles.Meanwhile, the opening series of tests for the J-2X Ares Upper Stage engine have been completed at NASA’s Stennis Space Center, which utilized J-2 components used from the Apollo program through the X-33 program.

**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**


**ORION/Exploration Vehicles LIVE UPDATE PAGES**



Ares I: 

The latest data, presented as an ‘end of April summary’, shows Ares I’s numbers as improving, with both the International Space Station (ISS) and Lunar variants of the vehicle meeting current performance requirements.

ISS Ares I A-104 (06907 booster) configuration – which is now without the nozzle extension, as previously reported – is classed as satisfying the performance requirement of 20,312 kg (44,780 lbm) to -11×100 nmi. 

The NET delivered mass, which is the actual useable payload, is pending at 22,231 kg (49,012 lbm), after all threats and opportunities are accounted for. The GROSS payload, which is the absolute bleeding edge of the performance envelope in this case, is 22,694 kg (50,626 lbm). 

The Lunar Ares I A-104 (26207 booster) also is currently meeting the requirement, which is 23,265 kg (51,290 lbm) to the injection target. The NET delivered mass is projected to be 24,600 kg (54,233 lbm) at this time. The maximum GROSS payload is 25,408 kg (56,104 lbm), which again is the performance ceiling for the configuration. 

However, none of these performance numbers account for any thrust oscillation reduction hardware or alternate concepts such as MLAS (Max Launch Abort System), or non-recoverable SRBs (Solid Rocket Boosters). 

The major project risks at this point – in order from greatest to least – are thrust oscillation (5×4 on the risk matrix), the common bulkhead (5×4), ground support equipment availability – with VAB (Vehicle Assembly Building) high bays, ML (Mobile Launcher) issues with different nozzles, Orion test articles – range from 4×5 to 2×4.

Also listed is the ability for Ares I to meet performance requirements (4×4), J2-X schedule (4×4), Ares V budget and performance (4×3), failure to meet LOM (Loss Of Mission) requirements (3×5), launch vehicle operability (3×4) and synchronization of Ares and Orion (2×4). 

All of the major Ares I hardware is still overweight by a total of 4,739 kg (10,447 lbm), of which over 4,200 kg (9,000 lbm) is from the first stage. Thrust oscillation, ground infrastructure impacts, getting heritage hardware to meet the new requirements, and reusability concerns, are among the first stage risks. 

The upper stage is mainly concerned with the common bulkhead, manufacturing, and being the long lead item on the vehicle. The J-2X engine is focusing on supporting the new powerpack 2, which is a 4×5 risk, in addition to getting the nozzle extension on track (4×4) and upper stage interface issues (5×5 and 3×5).


Ares I-X: 

Ares I-X is struggling to hold the 4/15/09 launch date due to the STS-125 (Hubble) mission slippage, alongside internal budget and schedule issues. 

Shuttle cannot hand over High Bay 3 or Pad 39B to Constellation until STS-125 flies – and more so LON-400 is cleared and rolled back off 39B – with the recent delays in the manifest not helping Ares I-X. 

However, if the delay is greater than another two months, MLP 2 may be available instead to keep I-X on track for 4/15. Constellation may also opt for a switch to taking over High Bay 2, especially with the ongoing discussions about extending the shuttle program to 2012. 

The production of flight article elements is progressing smoothly, with component manufacturing for the boilerplate hardware having already begun. The SRB drogue and main parachutes, avionics module, roll control system and the aft motor segment/skirt will all start fabrication by June. 

Deliver of the components will start with the RSRM (Reusable Solid Rocket Motor) segments in July and the interstage, upper stage, CM (Command Module) and LAS (Launch Abort System) by November in preparation for stacking to begin on 12/23/08. 

Before that can happen, the remaining risks, such as launch environment analysis (3×5), roll out stabilization (3×3), range safety certification (3×3), potential loss of vehicle control (2×5) or nose first reentry on the first stage (2×5), require refinement.

April saw Ares I-X reached its milestone of one year – currently – until launch.

To commemorate the milestone, the Ares I-X management team conducted a 4-hour status briefing to the Agency leadership at Stennis Space Center (SSC) on April 14.

The attendees included representatives from NASA Headquarters (HQ), the Exploration Systems Mission Directorate (ESMD), the Constellation Program (CxP), Center Directors, the Office of Safety and Mission Assurance (OSMA), and Shuttle.

“Ares I–X presenters conveyed accomplishments and forward work. The response from the Agency-wide audience was very positive regarding the Ares I-X team’s accomplishments and the plans leading to launch,” noted the associated presentation.

“Dr. Mike Griffin spoke about the importance of the Ares I–X flight test and the technical benefits that Ares I–X will provide to Ares. He stressed the importance of working across NASA Centers and reinventing our processes.”

A large amount of focus is continuing on Ares I-X’s Roll Control System (RoCS) element, and the Thrust Vector Control System (TVC).Orion: 

Orion is holding at a control mass of 19,296 kg (42,540 lbm) for International Space Station (ISS) missions, and 21,877 kg (48,231 lbm) for Exploration missions. However, these weights are not related to the “predicted” weights or margins. 

The program is also facing significant schedule pressure, with a delay to PDR now making its way through the program, following the decision by the CEV Project Control Board (CPCB) meeting on May 6. 

That meeting discussed a wide range of subjects, such as Orion mass status, unpressurized cargo forward planning, ascent and abort loads, cost threat mitigation, and integrated performance capabilities.

J-2X Upper Stage Engine:

The milestone of the completion of the opening series of tests for the J-2X is significant, following many months of build-up to the test runs on the system that is based on Apollo and X-33 heritage. Below is a short summary of some of the objectives achieved during testing in 2008. 

Build-up testing ran through 2007, prior to the J-2X Element Team successfully completing a Gas Generator (GG) Ignition test at the start of 2008, utilizing the J-2X Powerpack Assembly (PPA) on the A-1 Test Stand at Stennis Space Center (SSC).

That test successfully demonstrated GG ignition detection and satisfactory GG valve timing – with no noted anomalies. That test paved the way for a longer duration (36 second) hot fire test in February.

The fourth test of Powerpack 1-A (PPA 1-A) was completed on February 15, which was the first “mainstage” test – at an equivalent 218K lb thrust level. The test ran for the programmed 36 second duration.

On February 12-13, the Controller, Valve, and Instrumentation team conducted a PDR (Preliminary Design Review) for the instrumentation on the J–2X engine. That review included sensors (pressure, temperature, accelerometers) as well as the harnesses.

The review concluded with the recommendation to proceed to Critical Design Review (CDR) which is scheduled for October 2008.

On February 27, diffuser performance during J-2X mainstage operation was successfully demonstrated in Subscale Diffuser testing. The system achieved 0.07 psia vacuum pressure, well below the maximum limit of 0.16.

Little known is the fact that actual fabrication of hardware for the engine has already begun, with the J–2X Turbomachinery Oxygen Turbopump (OTP) Development Unit Hardware machining on the J–2X development engine started on March 6 at Pratt Whitney Rocketdyne in Canoga Park, CA.

The hardware will part of the Powerpack Assembly 2 (PPA–2) test activity scheduled for spring of 2010. 

Meanwhile, the J-2X Powerpack Test number 5 was performed on March 19. Over 50 seconds of full power was achieved with the Powerpack, providing valuable turbomachinery data for use in future design activities.

This was soon followed by the sixth test of PPA–1A, which was completed on April 3 at NASA Stennis Space Center (SSC) Test Facility A1. The planned duration was 550 seconds.

However, while the PPA-1A started at the 218K power level, after 10 seconds it transitioned to the 274K power level. At approximately 293 seconds, the test was terminated by a redline cut on the Liquid Oxygen (LOX) Annin valve position. The valve drifted open when the control cable came loose.

No other anomalies were noted during the purge sequences or test. The flowmeter calibration objective and the first of 5 Q/N data points (flow/speed) were obtained during the test. The data review for this test was held on April 7 and cleared for the following tests to be conducted. 

Also on April 3, a PDR was conducted for the J–2X Ancillary Valves (AVs). The AVs includes the three-way solenoid valve (SOV), four-way SOV, and the pressure actuated valve (PAV).

These AVs are mounted on the J–2X Pneumatic Control Assembly (PCA) and regulate the flow of pneumatics to control valve positions and purges. The CDR is scheduled for July 24. 

Test 7 on Powerpack 1A was successfully conducted at the SSC Test Facility A-1 on April 14. The primary test objective was to obtain J–2 heritage Liquid Oxygen (LOX) pump suction performance data needed to inform the J–2X LOX pump design.

The planned test duration was no longer than 350 seconds and was terminated at 240 seconds due to expected pump cavitation associated with the test objective. Preliminary data indicate all objectives were met. 

Two more tests closed out this opening series, with the ninth firing taking place on Thursday. The tests in the series ran for durations up to 400 seconds and at power levels up to 274,000 pounds of thrust.

“This series of tests is an important step in development of the J-2X engine,” said Mike Kynard, manager of the upper stage engine for the Ares Projects at NASA’s Marshall Space Flight Center (MSFC).

“We started with a number of objectives and questions we needed answers to as we work to complete designs of the J-2X engine. The data we have gained will be invaluable as we continue the design process.”

Detailed weekly presentations – available on L2 (over 150mb’s worth) from which the majority of the above information is based on – will be summarized in future articles, as progress is made on both Ares I-X and the Ares I hardware.

These presentations already include several months worth of photos and construction notes on the A-3 test stand, which is currently taking shape at Stennis – with an overview article set to be published early in the summer. 

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