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  SpaceX Dragon CRS-7 mission launch failure

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Author Topic:   SpaceX Dragon CRS-7 mission launch failure
Robert Pearlman
Editor

Posts: 42988
From: Houston, TX
Registered: Nov 1999

posted 06-25-2015 12:05 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
SpaceX release
SpaceX CRS-7 Mission Overview

After seven missions to the International Space Station, including six official resupply missions for NASA, SpaceX is preparing to launch its seventh Commercial Resupply (CRS) mission to the orbiting lab.

SpaceX's CRS-7 mission will launch on a Falcon 9 rocket from Space Launch Complex 40 at the Cape Canaveral Air Force Station, Florida.

If all goes as planned, Dragon will arrive at the station two days after lifting off. Dragon is expected to return to Earth five weeks later for a parachute-assisted splashdown off the coast of California.

Background and purpose

CRS-7 (SpX-7) is the seventh of at least 12 missions that SpaceX will fly under NASA's Commercial Resupply Services (CRS) contract.

In December 2008, NASA announced that SpaceX's Falcon 9 launch vehicle and Dragon spacecraft had been selected to resupply the space station after the end of the shuttle program in 2011. Under the CRS contract, SpaceX has restored an American capability to deliver and return significant amounts of cargo, including live plants and animals, to and from the orbiting laboratory.

Cargo

Dragon is filled with more than 4,000 pounds (1,815 kg) of supplies and payloads, including the critical materials needed to directly support over 30 student research investigations and more than 35 of approximately 250 science and research investigations that will occur during Expeditions 44 and 45.

Science payloads will offer new insight to combustion in microgravity, perform the first space-based observations of meteors entering Earth’s atmosphere, continue solving potential crew health risks and make new strides towards being able to grow food in space.

Dragon also will use its unpressurized trunk to deliver the first of two International Docking Adapters (IDA) to enable future commercial crew vehicles to dock to the station.

Dragon will return with about 1,400 pounds (635 kg) of cargo, which includes crew supplies, hardware and computer resources, science experiments, space station hardware, and trash.

Robert Pearlman
Editor

Posts: 42988
From: Houston, TX
Registered: Nov 1999

posted 06-28-2015 10:20 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
collectSPACE
SpaceX rocket explodes during launch of cargo capsule for space station

A SpaceX Falcon 9 rocket launching an uncrewed cargo capsule to the International Space Station broke apart just two minutes after lifting off from its Florida launch pad on Sunday morning (June 28).

The failure marked the commercial spaceflight company's first loss of a Falcon 9 after 18 successful launches since 2010, and the third loss of a supply-filled space freighter in less than a year.

The flight began normally, with the two-stage, 20-story-tall rocket leaping off the pad at the Cape Canaveral Air Force Station's Complex 40 at 10:21 a.m. EDT (1421 GMT). Two minutes and 19 seconds later, the vehicle disintegrated in a cloud of debris.

"Falcon 9 experienced a problem shortly before first stage shutdown," Elon Musk, SpaceX's CEO, said in an update posted to his Twitter account. "There was an overpressure event in the upper stage liquid oxygen tank."

Robert Pearlman
Editor

Posts: 42988
From: Houston, TX
Registered: Nov 1999

posted 07-20-2015 08:05 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
SpaceX release
CRS-7 Investigation Update

On June 28, 2015, following a nominal liftoff, Falcon 9 experienced an overpressure event in the upper stage liquid oxygen tank approximately 139 seconds into flight, resulting in loss of mission. This summary represents an initial assessment, but further investigation may reveal more over time.

Prior to the mishap, the first stage of the vehicle, including all nine Merlin 1D engines, operated nominally; the first stage actually continued to power through the overpressure event on the second stage for several seconds following the mishap. In addition, the Dragon spacecraft not only survived the second stage event, but also continued to communicate until the vehicle dropped below the horizon and out of range.

SpaceX has led the investigation efforts with oversight from the FAA and participation from NASA and the U.S. Air Force. Review of the flight data proved challenging both because of the volume of data — over 3,000 telemetry channels as well as video and physical debris — and because the key events happened very quickly.

From the first indication of an issue to loss of all telemetry was just 0.893 seconds. Over the last few weeks, engineering teams have spent thousands of hours going through the painstaking process of matching up data across rocket systems down to the millisecond to understand that final 0.893 seconds prior to loss of telemetry.

At this time, the investigation remains ongoing, as SpaceX and the investigation team continue analyzing significant amounts of data and conducting additional testing that must be completed in order to fully validate these conclusions. However, given the currently available data, we believe we have identified a potential cause.

Preliminary analysis suggests the overpressure event in the upper stage liquid oxygen tank was initiated by a flawed piece of support hardware (a "strut") inside the second stage. Several hundred struts fly on every Falcon 9 vehicle, with a cumulative flight history of several thousand. The strut that we believe failed was designed and material certified to handle 10,000 lbs of force, but failed at 2,000 lbs, a five-fold difference. Detailed close-out photos of stage construction show no visible flaws or damage of any kind.

In the case of the CRS-7 mission, it appears that one of these supporting pieces inside the second stage failed approximately 138 seconds into flight. The pressurization system itself was performing nominally, but with the failure of this strut, the helium system integrity was breached. This caused a high pressure event inside the second stage within less than one second and the stage was no longer able to maintain its structural integrity.

Despite the fact that these struts have been used on all previous Falcon 9 flights and are certified to withstand well beyond the expected loads during flight, SpaceX will no longer use these particular struts for flight applications. In addition, SpaceX will implement additional hardware quality audits throughout the vehicle to further ensure all parts received perform as expected per their certification documentation.

As noted above, these conclusions are preliminary. Our investigation is ongoing until we exonerate all other aspects of the vehicle, but at this time, we expect to return to flight this fall and fly all the customers we intended to fly in 2015 by end of year.

While the CRS-7 loss is regrettable, this review process invariably will, in the end, yield a safer and more reliable launch vehicle for all of our customers, including NASA, the United States Air Force, and commercial purchasers of launch services. Critically, the vehicle will be even safer as we begin to carry U.S. astronauts to the International Space Station in 2017.

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