Watch a SpaceX rocket booster spin out of control, splash into water

The
booster or first stage of a SpaceX Falcon 9 rocket attempting to
land.

SpaceX/Flickr
(public domain)

• Elon Musk‘s aerospace company,
  SpaceX, successfully launched a resupply ship for NASA to the
  International Space Station on Wednesday.
• As a cost-saving bonus, SpaceX also tried to land the 16-story booster of
  its Falcon 9 rocket on a ground pad at Cape Canaveral,
  Florida
  .
• However, videos show the Falcon 9 rocket booster spinning
  wildly before taking a plunge into the ocean.
• Musk blamed the anomaly on a faulty pump, but said the
  booster is undamaged, being recovered, and can be reused for a
  future launch.

On Monday afternoon, SpaceX successfully launched a 4.6-ton

Dragon cargo spaceship full of supplies and experiments to
astronauts in orbit.

“Dragon is on its way to the International Space Station. Capture
by @Space_Station crew set for early Saturday morning,” SpaceX,
the rocket company founded by Elon Musk, tweeted shortly after launch aboard a
Falcon 9 rocket.

As is now customary for SpaceX, the company also tried to land
the biggest and most expensive part of its
Falcon 9 rocket — the 16-story-tall booster, or first stage —
back on Earth for refurbishment and future re-launch. (Reusing
boosters could
save SpaceX billions of dollars over the years and lower the
cost of access to space, since orbital rockets typically crash
into the ocean.)

But as the giant booster came screaming back to Florida with some
fuel inside, a crucial system failed. The tense moment was
captured during a live broadcast from SpaceX’s headquarters in
Hawthorne, California.

The
main parts of SpaceX’s partly reusable Falcon 9 rocket
system.

SpaceX/Flickr;
Business Insider

About one minute before the booster was scheduled to land in Cape
Canaveral — while it was traveling at several hundred miles per
hour — it began to teeter and spin around and around. The sight
triggered a mixture of worried “oohs” and “aahs” from SpaceX
employees who were watching, then the booster’s video feed cut
out from the broadcast.

For a moment, it seemed as if the booster was flying out of
control toward the ground. But cheers soon erupted from SpaceX
employees. Musk later revealed that they were cheering the
success of a backup plan: the booster “landed,” as gently as a
towering object can, in the Atlantic Ocean.

“Falcon landed just out to sea. Appears to be undamaged & is
transmitting data. Recovery ship dispatched,” Musk tweeted. He added that the booster
will likely be reused for a future “internal” mission (which
likely means for the launch of SpaceX’s next-generation internet
satellites, called
Starlink).

A few minutes later, Musk and others shared some dramatic and
dizzying footage of the splashdown.

Watch SpaceX’s booster spin then splash into the sea

Musk shared the 45-second clip below, which picks up where the
live broadcast cut out.

The footage shows the booster spinning while firing its rocket
engines in an attempt to control the twirling and safely land —
but with no ground in sight. It pops out its four landing legs,
rockets toward the ocean’s surface, plunges in, bobs upward, and
then tips over like a felled tree.

Musk blamed the failure on a hydraulic pump that pushes out one
of the booster’s four titanium “grid fins.” These steerable,
waffle-like devices help the rocket guide itself toward a landing
site while returning to Earth, then stabilize the booster during
landing.

As Monday’s launch of the CRS-16 mission showed, not deploying a
grid fin in time can put the rocket into a tailspin, preventing
it from steering toward a landing site.

“Some landing systems are not redundant, as landing is
considered ground safety critical, but not mission critical.
Given this event, we will likely add a backup,” Musk tweeted.

SpaceX wasn’t the only one to film the dramatic moment.

Chris Gebhardt, the assistant managing editor of NASASpaceFlight.com, was recording the booster’s
return in Cape Canaveral with several others, and he helped
capture the whole event on camera.

The clip below shows Gebhardt’s and others’ view from the ground.
Several sonic booms from the booster’s supersonic descent to
Earth can be heard before it splashes down just out of sight
beyond a barrier island. (Turn on the sound to hear their
commentary.)

Don’t out-of-control rockets blow themselves up?

Rockets that veer out of control typically self-destruct using
what’s called an automated flight termination system, or AFTS.
Such systems are put in place to protect people and equipment on
the ground.

But in this case, self-destruct criteria weren’t met, and SpaceX
got to perform
a soft-ocean-landing maneuver that it has practiced before.

When SpaceX launched the CRS-16 resupply mission on Monday, it
made sure the Falcon 9 rocket’s booster would hit the ocean if
the landing system somehow failed. Only reigniting the booster’s
engines for a precise landing burn would have pulled it off that
trajectory and toward the ground pad.

A SpaceX Grasshopper
rocket self-destructs in August 2014 after an engine sensor
failure.

SpaceX/YouTube

If the booster had veered off-course more than two minutes before
landing, Gebhardt said, then it would have exploded.

“A water-ditch landing is safer than an exploding rocket close to
the ground,” he told Business Insider.

SpaceX is preparing to launch its first spaceship to carry NASA
astronauts, called
Crew Dragon, in 2019. If SpaceX rockets misbehave, that could
prompt the agency to perform a safety review and delay those
experimental launches.

But in this case, nothing that’d be considered critical to NASA’s
mission — only SpaceX’s convenience — seems to have gone wrong.