ADVANCES
14 Scientific American, May 2020S PA C E F L I G H TCountdown to Commercial Crew
nasa approaches the end of a winding path to commercial astronaut launches
When the space shuttle Atlantis landed and rolled to a stop
at Florida’s Kennedy Space Center in 2011, bringing the 30-year
shuttle program to a close, nasa hoped to fly U.S. astronauts
onboard privately developed space taxis within four years. But
budget shortfalls added two years to development schedules, and
then technical problems with parachutes and launch escape sys-
tems pushed key flight tests to 2019. Now SpaceX—the companyselected along with Boeing in 2014 to fly crews to and from the
International Space Station—is finally on the cusp of launching
two nasa astronauts on a long-awaited trial run. Boeing plans to
follow, possibly this year, although the company ran into software
glitches during its uncrewed test flight last December. Here’s a
look at the ups and downs of nasa’s decade-long effort to restore
human orbital spaceflight in the U.S. — Irene KlotzJULY 2011 A four-person crew, headed by
then nasa astronaut Chris Ferguson, returns
from a nearly 13-day cargo run to the space
station onboard the shuttle Atlantis, capping
the 135th and final mission in the three-decade
shuttle program. Crew ferry flights are turned
over to space station part-
ner Russia, which today
charges about
$86 million per seat.JULY 2015 nasa embeds four
astronauts—Bob Behnken, Doug
Hurley, Sunita Williams and Eric
Boe—at SpaceX and Boeing to
learn about the new spacecraft
and pass along hard-learned les-
sons from the shuttle program.MAY 2015 SpaceX
demonstrates how
its Crew Dragon
capsule, also known
as Dragon 2, would
fly itself to safety if
its Falcon 9 rocket
failed on the launchpad
or shortly after liftoff.SEPTEMBER 2016 A SpaceX Falcon 9
rocket, set to carry an Israeli com-
mun i cations satellite into orbit,
explodes on the pad while being fueled
for a routine test firing of its engines
before launch. The accident prompts
a redesign of pressure vessels inside
the rocket’s fuel tanks and raises
questions about the company’s plan
to fuel rockets with crews onboard.AUGUST 2018
nasa assigns astronauts
to the first four Commercial
Crew missions. Behnken and Hur-
ley begin training for a SpaceX Crew
Dragon flight test, and Victor Glover and
Mike Hopkins begin training for Dragon’s
first operational mission. Rookie astronaut
Nicole Aunapu Mann is assigned along with
Boe and Ferguson (who joined Boeing
following the shuttle’s retirement)
for a flight test on Boeing’s Star-
liner; Williams and Josh Cassada
are assigned to Starliner’s first
operational mission. Boe is later
pulled from the flight for medi-
cal reasons and replaced by
Mike Fincke.
APRIL 2019 Follow-
ing Demo-1, SpaceX’s
Crew Dragon capsule
explodes on a test
stand during prepara-
tions for a static test
firing of the capsule’s
emergency escape
system engines.NOVEMBER 2019 Boeing tests
Starliner’s abort system by firing the
capsule off of a test stand in New Mex-
ico. One of Starliner’s three parachutes
fails to deploy, but the cap sule—as
designed—safely lands with two chutes.JUNE 2018 A propellant leak dur-
ing an engine test for the Boeing
CST-100 Starliner’s emergency
escape system, which flies a crew
to safety in case of an accident dur-
ing launch, spurs a valve redesign.MARCH 2019 A SpaceX Falcon 9
sends an autonomous Crew Dragon
capsule with 400 pounds of supplies and
equipment into orbit on its first trip to the space
station, the Demo-1 mission. The capsule docks at
the station for five days before undocking,
burning its engines to leave orbit and suc-
cessfully parachuting into the Atlan-
tic Ocean off Florida.SEPTEMBER 2014 Boeing and SpaceX win contracts to devel op
transportation systems and fly nasa astronauts. Boeing receives
$4.2 billion for two test flights to the space station—one uncrewed
and one crewed—and six operational missions. SpaceX bids and
receives up to $2.6 billion for a similar commitment. “Knowing
I could have bid more, after the fact, I sure wish I would have bid
more,” SpaceX president Gwynne Shotwell quipped in 2018.
“I hate to talk about profit when we’re flying
astronauts, but this will [still] not be
a losing proposition for SpaceX.”4123567