Friday, July 15, 2016

NASA Docks SpaceX

Kennedy Space Center Director Bob Cabana inspects IDA-2. Image source: NASA.

SpaceX is scheduled to make its next cargo delivery to the International Space Station early Monday, around 12:42 AM EDT. After launching the SpaceX-9 Dragon, the Falcon 9 booster will attempt to land at the Cape's former Launch Complex 13 about ten minutes after launch.

For NASA's commercial crew program, this is one launch where failure is not an option.

The two commercial crew capsules, which could arrive at ISS as soon as late 2017, require NASA's new International Docking Adapter (IDA) to dock with the station.

The first adapter was aboard the SpaceX-7 flight that was destroyed 139 seconds after launch on June 28, 2015.

NASA built two IDAs. The agency had planned to install one on each of the station’s two open Pressurized Mating Adapters (PMA), both of which are connected to the Harmony module. IDA-2 is aboard SpaceX-9.

A new third IDA, built from spare parts, is scheduled for delivery to NASA in March 2017. It will replace the lost IDA-1. It's scheduled for ISS delivery in February 2018.

If something goes wrong with Monday's SpaceX-9 launch, the loss of IDA-2 will push back NASA's ability to dock its new crew ships at ISS, and extend further reliance on Russia.

On June 28, NASA's Office of the Inspector General issued a report reviewing the SpaceX-7 loss, how it affected the agency, and evaluation of the SpaceX response to the incident.

According to the OIG report, NASA suffered a financial loss of $118 million from the incident, including the loss of IDA-1. The agency lost $51 million when the Orbital-3 mission was destroyed seconds after launch in October 2014.

The report states:

The most significant item lost during the SPX-7 mission was the first of two Docking Adapters necessary to support upcoming commercial crew missions. Although NASA had planned to have two Adapters installed on the Station before the first commercial crew demonstration mission scheduled for May 2017, it is now likely there will be only one installed in time for these missions. Having only one Adapter means that a commercial crew vehicle will not be able to dock with the ISS if technical issues arise with the single available docking port. ISS Program officials stated that they plan to have the replacement Adapter installed before regular commercial crew rotations begin.

The first-round commercial cargo contracts, known as Commercial Resupply Services 1 (CRS-1), “place much of the risk associated with an unsuccessful mission on NASA.”

However, this is not unusual for Government contracts relating to space operations given the associated expense and risks, and the limited number of capable contractors. Due to the relationship between risk and price, shifting more risk to the contractor would likely increase contract price. To this end, the CRS-1 contracts do not require SpaceX or Orbital to re-fly failed missions or carry upmass from a failed mission on future flights, nor do they make the companies liable for any cargo destroyed as a result of a launch failure or other anomaly. While, as previously noted, if SpaceX or Orbital fail to deliver cargo to the Station the companies forfeit any payment tied to the associated milestones, NASA is not entitled to recover previous milestone payments associated with the launch. Furthermore, the Agency can only recover milestone payments it has made toward missions not yet flown if it terminates the contract for cause — known as “termination for cause.”

After the SpaceX-7 accident, in December 2015 NASA negotiated modifications to the SpaceX’s CRS-1 contract to add five additional flights — SpaceX-16 through SpaceX-20 — at discounted prices.

The report also includes information about other programs not immediately relevant to the SpaceX CRS missions.

According to the report, the current SpaceX commercial crew schedule is to fly an uncrewed test flight to ISS in May 2017. The first crewed flight is scheduled for August 2017.

A table on page 4 (page 10 of the PDF) compares the capabilities of cargo Dragon, Orbital ATK Cygnus, and the cargo version of the Sierra Nevada Dream Chaser. SNC won a contract earlier this year to start ISS cargo deliveries by the end of the decade. Dream Chaser will be able to deliver more upmass to ISS (an estimated 5,500 kg) than Orbital ATK (3,500 kg) or SpaceX (3,310 kg).

Page 8 (page 14 of the PDF) details both SpaceX and NASA conclusions as to the cause of the SpaceX-7 loss.

Following the SPX-7 failure, SpaceX recovered parts of the Falcon 9 rocket and, through telemetry analysis and other testing, determined the most probable cause for the mishap was a strut assembly failure in the rocket’s second stage. Specifically, the failed strut assembly released a helium tank inside the liquid oxygen tank, causing a breach in the oxygen tank’s dome and the release of gas that in turn disabled the avionics and caused release of the Dragon 1 capsule and break-up of the launch vehicle. SpaceX completed an extensive analysis of the SPX-7 failure, consulted with NASA and the United States Air Force (USAF) regarding their analysis, and provided a mishap report and Return to Flight Plan to the FAA and NASA in November 2015. The company’s post-mishap testing of strut parts from the same purchase order as those used on SPX-7 found material flaws due to casting defects, “out of specification” materials, and improper heat treatment.

NASA’s Launch Services Program (LSP) conducted a separate, independent review of the failure, briefing its results to senior NASA leadership on December 18, 2015. LSP did not identify a single probable cause for the launch failure, instead listing several “credible causes.” In addition to the material defects in the strut assembly SpaceX found during its testing, LSP pointed to manufacturing damage or improper installation of the assembly into the rocket as possible initiators of the failure. LSP also highlighted improper material selection and such practices as individuals standing on flight hardware during the assembly process, as possible contributing factors.

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