Space Station in good health, prepares for busy Expedition 50 period
As part of the normal review process, NASA has updated the NASA Advisory Council (NAC) on the status of the International Space Station – including its overall health, upcoming visiting vehicle schedule, commercial resupply efforts, and battery deliveries and associated installation EVAs that will upgrade the Station into its next phase of operation and propel its lifetime to 2024.
General health of Station:
Overall, the now 18 year-old Space Station (based on launch of the first ISS module on 20 November 1998) is operating in excellent condition and far exceeding overall systems expectations.
While Sam Scimemi, ISS Director at NASA Headquarters, noted that a few systems and components have not behaved as well as the overall system, he stated to the NAC that “In general, if you average all the systems, we’re doing much better [than the expected lifetime].
“Space hardware is designed to last longer, and it does typically last a lot longer than predicted. And we’re seeing that in our experience.”
However, Mr. Scimemi did state that “We’ve had some particular problems with particular pieces of systems. In particular related to life support like our ECLSS (Environmental Control and Life Support System) system. We’ve had individual pieces of equipment like valves that have given us trouble. We had some avionics parts failures that were happening because of a manufacturing issue.
“So there have been individual pieces that have been giving us issues and have been failing far more quickly or more often than designed. But Station as a whole has outperformed in general from back when it was originally designed.”
In terms of systems that have given controllers some issues, Mr. Scimemi specifically noted the Oxygen Generation Assembly (OGA) on Station.
“Our oxygen generation system that’s been on Station and operating very well for the past five years or so finally gave out [in late-October].”
The OGA is a critical piece of life support equipment as it generates much of the oxygen needed to support a six person crew on Station.
For this particular OGA failure, the failure occurred during the three-person crew period of station hand-over operations.
Because of the timing of the failure, Mr. Scimemi noted that “We had the Russian Elektron providing oxygen, and we worked with the crew to install the spare OGA” we had on board.
Removal & Replacement (R&R) of the OGA finished on 9 November, and the new unit has been up and running “at a nominal 22%” ever since.
Spare parts for the newly-installed OGA will be flown to Station on the scheduled 1 December launch of Progress 65P, and a full spare OGA will be launched on the upcoming OA-7 flight of Cygnus on Atlas V from the Kennedy Space Center in March 2017.
The NAC then followed up on the OGA discussion, asking about the predicted lifetime of the OGA.
Mr. Scimemi noted that the OGA carried a lifetime of 5 years, so it met its certification criteria in that regard.
For the NAC, the conversation about the OGA continued, with questions regarding a potential generic issues with the OGAs – including the spare just installed on Station.
Mr. Scimemi stated that the referenced issue is within the cell stack of the OGA.
“We thought that this failure might apply to the spare as well. But this spare is up and operating, so we’re doing that [investigative] work right now” on the ground.
Mr. Scimemi then used this opportunity to talk to the NAC about how this specific issue is being worked in terms of the anticipated introduction of a next generation OGA system to the Station beginning in 2019.
“The things we’re learning from the entire ECLSS system we’re applying to the next generation system. We’re taking all these lessons in terms of design and also in terms of the way we operate the systems.”
In terms of the next generation OGA, Mr. Scimemi noted that it’s anticipated to start going up to Station in 2019 – with a few years of installation work before it’s fully integrated to the Station.
Importantly, this next generation OGA is representative of the larger work and education of the systems the ISS affords NASA.
According to Mr. Scimemi, Station engineers never intended to redesign the OGA. But real-time operations and data have changed that position.
Moreover, in terms of Station outfitting, Mr. Scimemi overviewed the installation of the International Docking Adaptor in August.
“Back in August, we did the IDA installation. It went quite well, and [the crew] performed all the tasks they expected” from a technical standpoint, though there was a loss of comm in EV-1.
“It turned out to be an issue between flight and the ground,” stated Mr. Scimemi. “To this end, the vehicle teams are working to make sure that doesn’t happen again.
“Moreover, back in September, we retracted the temporary thermal radiator that’s been out on the end of the Truss.
“We assisted it down and installed the shroud, and it went very well. And we were actually able to complete several get ahead tasks.
“We were able to install a high definition camera and we tied back the CETA cart brake handle. So that’s another EVA that went very well” earlier this year.
Importantly, Mr. Scimemi also overviewed the current status of consumables aboard the Station.
Specifically, Mr. Scimemi noted that the ISS program has learned how to better manage its consumables (i.e.: water and food).
Currently, there is enough food on ISS to take the crew out to April 2017 (to June with rationing).
However, that assumes that all upcoming resupply missions in December and January fail to arrive at Station.
If the upcoming Progress 65P mission is successful, food supplies will last out until mid-May 2017 (July with rationing).
At present, the limiting consumable on Station is water, with current supplies under normal usage lasting until March 2017 – 14 June under crew reduction or rationing operations.
If Progress 65P is successful, water supplies will nominally last through 2 May 2017 – 1 August with crew reduction or rationing efforts.
Visiting Vehicles and Commercial Resupply efforts:
While Progress 65P is the first of the upcoming Visiting Vehicles (VVs) set to launch to the ISS in December, the first half of the month is projected to be an intense period of VV activity for the six-person Expedition 50 crew.
Progress 65P is set to launch on 1 December and dock to the Station on 3 December – followed closely by JAXA’s HTV-6 resupply craft.
“We have HTV coming up,” notes Mr. Scimemi. “That’s planning to launch on December 9th, and it has all of our important batteries” for our January EVAs.
HTV was initially set to launch earlier in the fall, but a fuel line issue necessitated a destack and swap out to correct the issue.
Mr. Scimemi noted that JAXA is now back into a readiness posture to launch HTV on 9 December, which under the most-recent Flight Planning and Integration Panel document – available for download on L2 – will place HTV-6 at Station for grapple and berthing on 13 December.
In all, HTV-6 will deliver 2,750 kg of pressurized cargo and 1,400 kg of external cargo – the six batteries.
Once those batteries are at Station, the Expedition 50 crew will be tasked with R&Ring the current set of batteries with the new ones.
According to Mr. Scimemi, “Coming up in January, we’ve got two critical EVAs based on the batteries being brought up on the HTV.
“These batteries are critical for the overall long-duration extension of the Station to 2024 and beyond.”
To aid the Expedition 50 crew’s EVA tasks with the batteries, ground robotic controllers have already used the Dextre robot on the exterior of the Station to break all the torque on the bolts on the installed batteries.
Mr. Scimemi noted that this robotic operation went very well, even “better than expected.”
While only two EVAs are currently planned for the battery R&R, there are two back-up, contingency EVAs also in the schedule should the R&R run into issues and require more time.
After 65P and HTV-6, the next officially scheduled resupply mission to Station is the 3 February 2017 launch of the 66P Progress, followed by March’s OA-7 launch of Cygnus.
It remains entirely possible that SpaceX will be ready to resume flights to the ISS in the January 2017 timeframe – assuming a successful recovery to flight operations from the AMOS-6 accident on 1 September 2016 and the completion and activation of LC-39A at the Kennedy Space Center.
Specifically, Mr. Scimemi noted that three NASA personnel are participating in the SpaceX Anomaly Team investigation, and NASA has also set up an independent review panel to examine whatever conclusions come from the AMOS-6 investigation.
Mr. Scimemi also noted that damage to SpaceX’s SLC-40 pad at the Cape Canaveral Air Force Station “was extensive” and SpaceX is focusing on getting LC-39A up and running.
However, the NAC had several concerns/questions regarding SpaceX’s investigation.
Mr. Wayne Hale specifically noted that “Usually we don’t go forward until we know an exact root cause or an underlying cause. And I don’t think they’ve gotten to that point (an exact root cause) in this investigation.
“If they don’t find a real underlying cause, just an idea of what it was, but they don’t have a corrective action, does NASA have any thoughts on that or what we plan to do?”
Mr. Scimemi answered that “many anomalies never get to hard root cause. A lot of times we get to the most probable cause, and we’ve had that before.
“So what happens is that since NASA is participating in the anomaly investigation team, we actually understand all the technical rationale of how they get to where they potentially get. And all that knowledge will be given to NASA as well as all the corrective action before return to flight.
“And that’s all spelled out in the CRS contract. So [SpaceX will] have to prove to NASA that it’s safe to fly when they’re ready to fly. And we will actually have to accept what they found and what the corrective actions were.
The NAC continued questioning the possibility of “no corrective action” on SpaceX’s part, asking if Mr. Scimemi expected there to be “some corrective action even though [SpaceX] might not be able to determine root cause? Or might [SpaceX] move forward with this as a one-time anomaly?”
Mr. Scimemi stated that the teams have not “gotten to that point yet.”
Regardless of when SpaceX is able to resume CRS-1 contracted flights to ISS, Mr. Scimemi noted that NASA has completed the first and second milestones of the CRS-2 contract awards with SpaceX, Orbital ATK, and Sierra Nevada.
Additionally, “we’ve kicked off the third milestone with Orbital ATK, and we expect to kick off the third milestone for Sierra Nevada and SpaceX soon,” noted Mr. Scimemi.
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