NASA’s Aerospace Safety Advisory Panel (ASAP) have gone on record to say they are satisfied with SpaceX’s explanations, relating to their “fast” scrub turnaround for Falcon 9’s May launch. After claiming they were initially concerned with the pace of the turnaround, the ASAP members were reassured via overviews provided to them by NASA and SpaceX’s Mission Assurance manager.
ASAP and SpaceX:
This latest meeting of the ASAP was once again chaired by Vice Admiral Joseph W. Dyer, USN (Ret.), and held at the Kennedy Space Center (KSC) near to the end of last month. Their findings and recommendations were passed on to NASA administrator Charlie Bolden – for his consideration – on August 8.
The VADM opened the meeting with praise for KSC Center Director, Robert Cabana, thanking him for “shepherding” his organization through “a very challenging time”, before adding KSC’s progress during its transition “is better than the Panel could have hoped for,” thanks to the institution’s leadership.
The ASAP were an active force in the drive to end the life of the Space Shuttle fleet, and were meeting at KSC just as Endeavour is being put through the final preparations to leave her home base for a retirement in California, an event that will leave the famous spaceport with just one remaining orbiter for the first time in close to 30 years.
The Panel also spent some of their energy over recent years urging caution with respect to the commercial space program, most notably on the commercial crew future that is tasked with returning a domestic ability for the United States to launch its own astronauts – a capability lost via the retirement of the Space Shuttle fleet.
However, the panel members have softened their stance towards NASA’s commercial partners recently, opting to praise SpaceX on their recent – and highly successful – C2+ mission, albeit with the inclusion of a few side notes of caution, with the previous meeting at the Marshall Space Flight Center (MSFC) citing “a few successes” should not detract from pushing commercial companies through NASA’s strict certification requirements for upcoming crewed missions.
Notes from the latest meeting also included special attention for SpaceX, this time examining the short scrub turnaround between a pad abort for Falcon 9’s opening attempt to launch Dragon on its debut mission to the International Space Station (ISS), and the successful launch that followed just a few days later.
The opening attempt was scrubbed – just seconds prior to launch – due to the breach of redline limits by Engine 5’s chamber pressure readings on the Falcon 9, causing the flight computers to abort the launch. Due to the near-instant launch window for this mission, a scrub was called for the day.
A similar, but not identical, issue was observed with the first flight of the Falcon 9 – an issue that was resolved ahead of launch due to an extended launch window for that opportunity.
After the Falcon 9 was detanked, engineers arrived at the pad to inspect the engine – specifically the chamber hardware – and soon found an obvious problem with a check valve on the engine’s turbopump.
“Engine pressure anomaly traced to turbopump valve,” noted SpaceX CEO and Chief Designer Elon Musk at the time. “Replacing on engine 5 and verifying no common mode.”
With the vehicle rolled back to the hanger for repairs, SpaceX engineers fixed the hardware on the Saturday night and reviewed the data the following day, allowing for the Falcon 9 to be rolled back out to the pad and returned to a launch stance by the Monday.
While a large amount of data is restricted, the panel felt they could discuss the check valve issue, due to the root cause being released into the public domain by SpaceX. To that end, the panel heard from SpaceX’s Director of Mission Assurance, Scott Henderson and were briefed by an internal NASA report on the scrub turnaround procedures.
“VADM Dyer noted that there were some constraints on what information could be disseminated at a public meeting, based on International Traffic in Arms Regulation (ITAR) restrictions as well as SpaceX proprietary data,” stated the ASAP notes. “(However,) the Hon. Mr. (Claude) Bolton stated that everyone is aware that there was an automatic shutdown on the SpaceX launch in May.
“The problem was found to be due to a check valve, (and) the process used to return to a launch position was described during the briefing, which was made by Mr. Scott Henderson, Director of Mission Assurance for SpaceX.”
The subject was discussed by the ASAP due to an apparent concern with the pace of the turnaround, with the notes adding “VADM Dyer observed that the turnaround was so fast that there was initially some concern on the Panel’s part that sufficient work may not have been done to identify root cause.”
However, after hearing from Mr Henderson – and verifying NASA’s own report into the anomaly resolution by the SpaceX engineers – the ASAP saw no items of concern.
“The ASAP understood from NASA’s report that the process was effective and efficient, turning around for a second successful launch attempt in three days; it was thorough, robust, fast, and transparent to NASA,” the meeting notes added.
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Due to the proprietary nature of SpaceX’s vehicle, no information has been released on how Engine 5 performed during ascent – as much as the vehicle clearly performed its required tasks. However, the ASAP went on record to say they are satisfied with the information they have to hand.
“After further review, the ASAP was satisfied with how this class D-equivalent mission was treated.”
Given the ASAP hold a large amount of influence at the Agency and political level, their recent positivity over SpaceX’s practises is important, and timely – as NASA close in on providing final approval for SpaceX to transition from their Commercial Orbital Transportation Services (COTS) obligations – of which the C2+ mission passed the final objectives – to their Commercial Resupply Services (CRS) missions to the ISS.
Pending that expected approval via NASA, L2 (LINK) information shows SpaceX have an opportunity to launch the first two CRS missions before the end of this year.
Current information places the CRS-1 (SpX-1) mission with a NET (No Earlier Than) launch date of October 6, to be followed by the CRS-2 (SpX-2) mission, launching NET December 16. Manifested payloads up to at least CRS-3 (SpX-3) are also listed on documentation (L2 LINK).
(Images: via SpaceX, NASA, and L2’s SpaceX Dragon C2+ Mission Special Section – Containing presentations, videos, images (800mb of unreleased hi res images from the mission) and more).
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