Accelerated launch schedule is ambitious

by Chris Bergin

For STS-116 to launch early in December, NASA need a number of crucial elements in their processing flow to come together, as documents acquired by this site show it will be anything but plain sailing to make a third launch this year on an accelerated launch schedule.

No contingency days remain in the STS-116 flow and the supporting LON (Launch On Need) processing flow for Atlantis is behind schedule.

**Information taken from four of the PRCB presentations. All PRCB presentations available to download on L2**

**STS-116 Launch Processing Updates** – Click on images below for larger screenshots of selected images from the related presentations**

While the United Space Alliance (USA) have already proven their ability to turnaround orbiters for the opening salvo of the ambitious final manifest for the fleet, some issues may even be out of their hands.

The approval to move the NET (No Earlier Than) launch date for STS-116 up a week to December 7 surprised a number of people, especially on the rationale associated with the decision.

Moving the launch up a week was under consideration for over a month, noted on NASA memos relating to the issue of being unable to fly an orbiter on orbit through a change of year, known as the YERO problem. At the time the change was dismissed – according to sources – as overloading the orbiter workforce schedule, and ET-124, the LON tank required for Atlantis, delivery date concerns. 

Four PRCB (Program Requirements Control Board) presentations make it more than clear that the ability to make December 7 will require not only an accelerated work schedule for workers involved with processing both Discovery and Atlantis, but that any hit on the processing flow would make what sources class as a ‘mockery’ on the new NET date.

The documents, acquired shortly after the PRCB meeting, show the approval to move to the December 7 NET date is to save workers from having to sacrifice large parts of their Christmas holidays. However, Considering Discovery herself, the United Space Alliance make a point of noting impacts to their orbiter workforce.

‘Extended and holiday launch countdowns for STS-121 and STS-115 drove notable maximum work time deviations and violations. Increased likelihood of driving > 2500 hours in 52 consecutive weeks violations. Currently monitoring/managing time of approximately 200 employees with potential of exceeding 2500 over next few months. Acceleration of STS-116 will eliminate opportunities to give some employees expected time off.’

Also of interest is the reference made to saving workforce from working over the Christmas holidays, which seems to be countered by the summary comments: ‘To preserve contingency days at the pad, Ground Ops may work Thanksgiving holiday. Post OV-103 roll-in work will have to be performed over Christmas holiday for either launch date.’

All areas of the Shuttle program – and related NASA centers and departments – noted their approval of the advancement of the STS-116 launch date, it should be noted. However, concerns were noted in the comment sections.

An example of which came from the ISS (International Space Station) program, who noted: ‘Some hardware items planned for launch on flight 12A.1 already had aggressive schedules to meet.

‘This launch acceleration compresses those schedules further, increasing the possibility that the hardware may not be delivered in time for launch. The main items at risk are the CDRA Bed ORU, the Ammonia Respirator, and the TVIS Gyro. The Vehicle Office/OB will manage these hardware schedules and endeavour to deliver in time for flight 12A.1.’

On the need for STS-116/Discovery’s processing flow, USA made it clear in their approval that there are no contingency days left in the launch flow. Any impacts will immediately place December 7 in doubt – something that can be expected with the orbiter still undergoing post STS-121 processing.

‘Ground Operations will become a ‘Yellow’ risk due to high likelihood of processing schedule impact as follows: The current STS-116 OV-103 OPF processing schedule has no contingency days available. TPS processing is the critical path.

‘To mitigate the impact of this change will require an increase in the overall processing density of our third shift and weekend operations. This will entail additional overtime costs and an increased risk of exceeding the OT guidelines (2500 hrs). Currently there are approximately 200 employees with the potential of exceeding 2500 hours over the next few months. Overtime budgets for September and October will be exceeded.

‘The acceleration of GFE deliverables and an early P/L to the pad is required to support this change. P/L delivery prior to SSV rollout to the Pad is required to maintain a green integrated processing schedule.’

USA plan to try and aid the accelerated plan by pulling workers off Endeavour – currently in preparations to make her first launch in four years on STS-118. ET workers will move to six days a week processing, with ET-123 targeted to be ready to accept Discovery for mating on November 1 – the date Discovery is now hoped to rollover from her OPF (Orbiter Processing Facility).

Issues with the new schedule also related to payload, which noted: ‘Late cargo deliveries delivery may prevent an 11/03 SSPF SPACEHAB arrival. OGS yellow schedule risk of late delivery. The current Study Only pad flow has payload IVTs late in the flow (11/27-28) and there may not be adequate time for problem resolution.’

As of right now, mitigation plans appear to aid processing for STS-116’s new launch date, bar Discovery herself. The Ground Ops Processing shows the orbiter as ‘Red’ for her Critical Flow Path, even for the 14th to 24th December launch window.

However, large scale concerns related to Atlantis, with the requirement to support her sister as the LON vehicle.

The whole processing flow for all elements of the LON launch (STS-317) are ‘Red’ – working off a 60 day CSCS (Crew Shuttle Contingency Support). That has now – it can be assumed – been reduced by another seven days.

Initially the main cause of concern was ET-124’s delivery date, although mitigation processes at MAF (Michoud Assembly Facility) have aided the shipping dates in recent months. However, to support even a December 14 launch date, LON requirements call for ET-124 to be on dock at the Kennedy Space Center (KSC) by December 11. Currently ET-124 won’t even finish construction at MAF until December 12.

Natural mitigation of that concern would be extra allowance in the CSCS timeline, the amount of time the ISS could support its own crew, plus a stranded Discovery crew awaiting rescue from Atlantis. Ironically, that is out of the control of orbiter processing.

Noted as ‘Mitigation Concerns : CSCS calculations assume Elektron working (due to having 1 spare),’ the O2 supplies on the ISS – and the performance of the troublesome Elektron oxygen generating machine will be a crucial factor associated with the CSCS timeline on the accelerated launch schedule.

A successful launch and docking from the next Russian supply ship will be vital, as an On Orbit Status Report from the ISS noted that the October 27th arrival of Progress M-58 will deliver an additional 50 kg of O2 (57 man/days).

While the ISS have plenty of reserve oxygen to counter any further Elektron issues, CSCS timelines will rely on monitoring the overall capacity of the ISS to support a stranded crew.

What is certain is the need to emphasis what a NET date means. By no means is December 7th set in stone, with a Space Shuttle Program manifest review set to take place on October 16. Same applies to the LON flight: ‘All the rescue flight launch dates are scheduled when the orbiter is ready. ET schedules are ignored because those schedules are under review.’

One of the strangest absences from the December 7 launch date decision is the range. Currently the range belongs to a Delta V launch, and with the Shuttle no longer having priority over the range, an agreement will need to be resolved in order to remove a 48 hour hit to Discovery’s launch plans. At present the range is ‘first come, first served,’ thus the Delta V launch holds the range for the opening of the new STS-116 launch window.

An expected return to Shuttle flights is the confidence in allowing night launches. Part of the decision making process with STS-116 was to confirm the required tracking of debris could be fulfilled during a night launch scenario.

However, there was concerns on this decision that were raised by JSC (Johnson Space Center) Engineering, who noted that while ‘A night launch provides no increased risk for the given flight. A night launch provides some increased risk for future flights.

‘Reduction of ascent detection asset capability results in a lost opportunity to improve understanding of the ascent debris environment (release time, location, and size). This also prevents the opportunity for detecting release of a debris source that is potentially critical for future flights for which risk was previously unknown or miscategorized. Both of these result in a missed opportunity to update debris risk assessments (could miss a risk source that is unacceptable)

‘Imposing a daylight launch constraint also has also risks / negatives. This constraint reduces program flexibility by restricting launch opportunities; both in number of windows and length of a given window. In addition to reducing the potential for success in completing space station assembly, this reduces the timeframe available to address issues identified close to or inside an available window.

‘Conclusion: Given no increase risk for the given flight and the trade of some increased future flight risk vs added flexibility & time to address prelaunch issues, JSC engineering recommends night launch acceptability with a caveat for certain significant redesigns that require ascent imagery (alternate opinion says we should stay with daytime launches based on the above).’

Getting to the point where Discovery will close in on a December 7 launch target will prove to be a challenge that NASA has managed to achieve before. However, with the added constraints of requiring another orbiter to be ready to launch within a set timeline for LON support, NASA has a far bigger challenge ahead of them in the next nine weeks.

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