SLS Program working overtime to make 2018 debut
Exploration Systems Development (ESD) Deputy Associate Administrator Bill Hill explained plans to mitigate flow concerns – such as recent adjustments to the Space Launch System (SLS) Core Stage delivery schedule – to keep the program on a path to launch Exploration Mission-1 (EM-1) in late 2018. Mitigation may include extra shifts to find margin in the schedule.
Working a Path – Stepping on the Gas:
ESD’s “build-to-sync” review, which will continue into the Fall, is currently looking at how Orion, SLS, and Ground Systems and Development and Operations (GSDO) work will fit together for EM-1.
The Orion, SLS, and GSDO programs have been working on parallel development paths to complete work to get ready for EM-1, and ESD will be in charge of final integration of that work as it comes together at the Kennedy Space Center (KSC) in Florida.
The three programs have gone through their critical design reviews, and now ESD is reviewing how the work and the schedules fit together now and in the future, including the challenges of integration in both areas.
“Each of the programs went through the typical systems engineering approach – you do a systems requirements review (SRR), and then a preliminary design review (PDR) and then a critical design review (CDR),” Mr. Hill explained in an interview with NASASpaceFlight.com
“For the integration ‘stuff’, we did a systems requirements review, but our ‘parallel’ to the preliminary design review was what we call a ‘design-to-sync.’ So we reviewed all of our design products there. And then this past spring and summer we did what we call ‘build-to-sync,’ which is kind of a parallel to the critical design review that each of the programs did.
“(That involved) pulling together the 170-plus products that we, under the Exploration Systems Development portfolio, have developed from an integrated standpoint.”
Recent schedule forecasts have the integrated EM-1 Orion spacecraft and the SLS Core Stage arriving at KSC a few months later than earlier predictions, which were used to derive the current September-November, 2018 launch readiness period, and Hill noted that they are looking at different ways of adjusting the work at KSC to try to meet that window of time.
“I have a team right now taking a look at if we get Core Stage (to KSC) at the end of March (and) get Orion at the end of April, early May of ’18, can we still make the September-November timeframe (for launch),” he explained. “We believe we can.
“Until recently, everybody assumed that there was a hard nine-month schedule (at KSC). We’re interrogating that; we don’t think it’s nine months – it was based on a one shift, five days a week schedule.
“So we’re looking at ‘what if we introduce a three-shift, six days a week or a three-shift, seven days a week [schedule]?’ We’ll probably go to six days a week, just to give us a little margin. (We’re looking at) if we do that, how much do we shrink down the schedule from nine months?
“(A) ‘back of the envelope’ look (says) we can get (the schedule) down to seven months and still keep thirty days of margin in there. (And we’re also looking at) how do we shrink it down even more.”
In addition to looking at adding work shifts to the KSC schedule, ESD and the three programs are looking at the work itself to see if time could be saved there.
“We’re also looking at the integrated tests that are going to be done at Kennedy,” he explained. “We had planned to do a Wet Dress Rehearsal (WDR), a full up (launch countdown) rehearsal. We may be able to do a tanking test, get that behind us, and not have to do a full up wet dress, because Orion really doesn’t get a lot of fueling or anything like that (in a WDR).
“We might be able to do that independently of Orion, so we might go out to the pad without Orion and do those tests.”
Other examples of refining the path to EM-1 includes the additional pre-mate, pre-launch testing involved with the Mobile Launcher.
“We had planned to do a full-up Mobile Launcher test at the park site and then take it into the Vehicle Assembly Building and basically repeat all of those tests,” Mr. Hill added.
“(The) Vehicle Assembly Building looks like it’s going to come in a little bit ahead of where we thought it was, so we might be able to just bring in the Mobile Launcher in and just do that test once – that takes a few weeks (of work) out of the schedule.
“So we’re looking at other options – that’s what they pay us to do, they pay us to try to deliver on time and on budget and we going to continue to do that on a daily basis.”
The build-to-sync effort that started earlier this year will continue into the Fall of this year. Mitigation of schedule concerns over two years ahead of launch will provide the program with options.
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“What we’ll do is work our way through whether we choose a specific launch date or maintain the two-month window,” Mr. Hill added. “We’ll see how we come out in the end. That will culminate with an agency review sometime in the late October timeframe, early November.”
In the interview at the Michoud Assembly Facility (MAF) in New Orleans, Louisiana, where the first SLS Core Stage is being manufactured and assembled, Mr. Hill added also talked about recent adjustments to the Core Stage schedule for EM-1 that has impacted on the schedule discussions.
“We just went through a renegotiation with Boeing and rebaselined the entire (Core Stage) schedule; we’re sticking to that schedule.
“We believe that we can ship out of here (MAF) with the engines integrated to get to Stennis in the September (2017) time-frame, get it on the B-2 test stand – where we’re going to do a full-up Core Stage hot-fire.”
Although the schedule is still targeting shipment of the Core Stage from MAF to Stennis in late September, 2017, the rebaseline does lengthen the time spent at Stennis for the “Green Run” test campaign before the Core Stage is put back on the Pegasus barge and shipped to KSC, which moved from January to March, 2018.
“Part of the renegotiation was to extend the time at Stennis – one of the things we did that we hadn’t planned on (earlier) was to repair the Core Stage if we damaged it somehow during the hot-fire,”
That renegotiation had a ripple effect on the EM-1 flow, with Mr. Hill explaining the Program will have to step on the gas to counter such changes.
“We’ve added in about thirty days for that in that schedule. There’re some other areas where we were really assuming – you’ve heard of ‘green-light’ schedules?
“I call the next step above that a ‘motorcade’ kind of a schedule where you don’t worry about green lights or red lights, you just blow through everything.
“We were kind of not as conservative on our first go-round and I think we’ve got a more realistic schedule today and that’s why it’s where it’s at.”
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