The SpaceX Falcon 9 rocket carrying the Dragon capsule on the CRS-7 resupply mission to the International Space Station suffered a failure of the second stage and
disintegrated seconds after passing through maximum aerodynamic pressure. The rocket and cargo are presumed to be a total loss. Credit: Alan Waters/AmericaSpace
By Chase Clark
After a string of 18 successful
launches to begin its pedigree, a
Falcon 9 rocket manufactured by
SpaceX suffered a catastrophic
failure during its ascent to orbit on
Sunday, June 28.
The Falcon 9 rocket was attempting to loft the Dragon capsule and
service trunk on the CRS-7 resupply
mission to the International Space
Station. The rocket had passed
through the area of maximum aerodynamic pressure (max Q) and was
within 20 seconds of burnout of the
first-stage Merlin engines, when the
rocket disintegrated at an altitude
of approximately 20 miles just 139
seconds after launch. The remaining
pieces of the rocket fell harmlessly into the Atlantic Ocean off the
Florida coastline.
While the exact cause of the rocket’s demise is stil unknown, SpaceX
founder Elon Musk tweeted on June
28 that there had been an overpressure event in the liquid oxygen fuel
tank of the second stage of the
rocket, and that downlinked data
streamed from the rocket during the
ascent indicated a counterintuitive
cause.
The following morning, Musk
tweeted that after several thousand
hours of engineering review that the
cause was still unknown.
The fact that the root cause of the
failure is not immediately apparent
is no cause for concern. A thorough
fault tree analysis may take several
months or longer to complete.
SpaceX is leading the accident
investigation, with assistance offered
by NASA, the FAA and the U.S. Air
Force.
In slow motion video of the
rocket’s ascent, it appears that the
second stage of the rocket ruptured
and disintegrated, while the Merlin
engines of the first stage continued
to push the rocket upward for a few
seconds. Video also shows that the
Dragon capsule may have separated from the upper stage and fell
uncontrollably into the ocean. It has
not been located and recovered,
nor is it known if it is still intact.
While SpaceX had recently
conducted a successful Pad Abort
Test of a redesigned version of the
Dragon capsule meant to carry
humans to the ISS and beyond, the
Dragon capsule used for the CRS-7
launch was the cargo-only version
that does not have abort during
ascent capability.
The Dragon capsule and service
trunk was carrying more than 4,000
pounds (1,800 kg) of food, water,
supplies and experiments to the
space station. Included among the
cargo was the first of tw