Constellation Challenges – test and flight schedules under pressure

by Chris Bergin

The Constellation Program is continuing to push through technical and monetary challenges in an attempt to protect the long term schedule.

The latest internal workings are currently being implemented into the Initial Operational Capacity (IOC) schedule, which shows the threat of delays range through the entire schedule – from the Ares I-X test flight, all the way through to NASA’s return to the moon.

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Ares I-X:

Ares I-X now has little chance of making its April, 2009 launch date target, initially due to the delay of STS-125’s flight to October.

The first Ares related test flight requires the freeing of High Bay 3 inside the Vehicle Assembly Building (VAB) and Pad 39B – which will first host STS-125’s Launch On Need (LON) rescue shuttle (Endeavour/LON-400) – being vacated for modifications ahead of Ares I-X.

However, a new problem has now come to light with the MLP (Mobile Launch Platform) that will be handed over from Shuttle to Constellation for the test flight. This problem relates to the stability of Ares I-X during rollout to the Pad.

The modifications to the MLP initially called for Ares I-X to be placed on one set of the existing Shuttle’s Solid Rocket Booster (SRB) hold down posts, with a tower to be erected on the other set of hold down posts – with support for the vehicle between the tower and the interstage level.

When NASA changed contractors for the MLP work associated with Ares I-X, the design changed, omitting the adjacent tower, instead relying on three steel cables – 120 degrees apart – to help hold the vehicle steady during rollout.

Given the projected weight of the vehicle at rollout – with a heavy dummy upper stage – additional stability is now being called for, leading to a redesign of the MLP support structure.

In combination with the projected delay to handing over Shuttle resources post STS-125, internal scheduling is showing 60 to 90 days worth of delay to Ares I-X’s projected launch date.

Constellation-wide delays feared:

As the Constellation Program project their budgetary requirements, the first of two ‘Revs’ of the PRM (Program Manager’s Recommend) 08 are being conducted over the coming weeks.

Initial information points to a continuing slide of the Initial Operational Capacity (IOC) schedule – as first noted in documentation acquired by this site in January, which pointed to $700m shortfall in the Constellation budget. However, this was deemed as an opening draft, with the figures to be refined over the coming months.

However, that refinement – which is still ongoing – has failed to show any reduction of pressure on the Ares/Orion schedule, with delays of six months to a year remaining in the latest source information.

At present, the threats relate to a six month delay to the first Ares I ‘full up’ test flight, along with the first manned Ares I flight continuing to be under serious schedule pressure, with 2015 and even 2016 in some circles being mentioned as the best case scenario. The schedule also threatens a one year delay of the return to the moon.

Budgetary pressure is classed as the main reason for the schedule moving to the right, though technical challenges with Ares I, and especially the Orion (606C) design cycle, are adding to the pressures.

Ares 1 Top Risks:

A refinement of the ‘Top Risks’ for the Ares I program was recently carried out, which represents the main challenges of the program via the often-used risk matrix – which is three to four columns based on ‘Severity’ and four to five columns high based on ‘Likelihood’.

Already known is Thrust Oscillation, classed as ‘3×4’ on the risk matrix for the first stage. This challenge holds the ‘possibility that the thrust oscillation solutions will include significant changes to the first stage design.’

First Stage Dynamics is classed as ‘3×5’ on the risk matrix, which refers to ‘increased stack length and flexibility associated with the interstage and frustum,’ and the ‘potential that loads may exceed hardware capability, which could result in unacceptable dynamic responses.’

Work on Thrust Oscillation is also continuing on the Ares I Upper Stage, classed on the risk matrix as ‘5×4’. The associated Tiger Team is continuing to work on identifying the loads.

Concerns are raised with the ‘4×4’ risk on the Vibro-Acoustic Loads, which are deemed ‘greater than first expected, 44 g rms vs. 15 g rms, still waiting on loads data.’

Refined mass figures are also noted on acquired information, which lists Upper Stage Dry Mass as an ‘Allocation 28,520 pounds, now estimated at 31,526 pounds. Asking for an allocation increase to 30,817 pounds,’ along with Interstage Dry Mass ‘allocation 7,270 pounds, now estimated at 7,398 pounds.’

Interestingly, Upper Stage Residual Mass, makes an appearance for the first time on the latest information, which appears to be a new factor recently discovered, due to the opening allocation of zero pounds. This is now “estimated at 2,717 pounds” – which is an additional hit on Ares I’s figures.

The other Upper Stage notes relate to the J2-X engine, with an allocation of 5,450 pounds, “now estimated at 5,577 pounds. (isp goal is 448, now estimated at 448.2).”

Constellation Staff Meeting Notes also make a reference to the development process for the J2-X, which notes a test firing of an Apollo-era J2 engine at the Stennis Space Center. The engine was outfitted with the “souped up” pumps that were used during the testing of the X-33’s linear aerospike engine.

“Held a 293-second test on the J-2X engine. Had a facility side anon valve cut off, which shortened the scheduled 550 second run. This is the third facility issue and they are working with Stennis to understand. They did capture good data this time,” added the notes.

“The anon valve gives back pressure in the system and it has perennially been a problem; some valves are as old as the stand. The good news is that we’re having it on a non-critical path item like power pack. This is the time to resolve the issues with the valves.”

Another test firing for 550 seconds is due to occur at any time. An update will be forthcoming when that information in acquired.

At present, Ares I’s estimated performance is currently 54,722 pounds to insertion target, with a 99.7 percent confidence level (an industry standard).

Orion (Command Module and Service Module fully fueled) had an allocation of 52,070 pounds until the weight scrubbing last November, the current weight allocation is 51,290 pounds, now estimated at 51,876 pounds.

The figures are all classed as pre-mitigation of the Thrust Oscillation issue – which has now gained widespread media attention. That fact has not been lost on the Constellation management, as noted in the Staff Meeting notes by manager Steve Cook.

“A lot of press going on about thrust oscillation (TO) and the Government Accounting Office (GAO) report,” added the minutes. “Cook said that what is interesting is that if you read below the headlines, most were pretty good.

“The ones that had the more negative slant on TO also had the more negative slant on the workforce reporting the day before…..that the positive sense is that even bad press is good press.

“The focus is on the gap and whether NASA has been adequately funded to do the work they have. Even though the headlines read ugly, it is a program that exists and is funded, and now we need to keep the focus as pointed out by the others – the strategy for success is to get through the fall and on to the next team that comes onboard in January.”

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