NEWS | IN DEPTH
strument flown to another planet, used to
analyze the crystal structure of samples—
would find no place on board.
That hasn’t stopped scientists from proposing even more complicated experiments.
In January, NASA received 58 instrument
proposals. One would seek to germinate
plants as a first step toward increasing the
amount of oxygen on the planet. Another
team would build a solar-powered helicopter that could fly reconnaissance sorties of
hundreds of meters a day.
Payload selection is expected in mid-
July. Jack Mustard, a planetary scientist at
Brown University who led the science defi-
nition team, hopes NASA will opt for a con-
servative payload—something more along
the lines of what is riding aboard the small
Opportunity rover, now in its 10th year of
operation. The same considerations will
drive the choice of a landing site. Sites that
require more than 10 kilometers of driving
will be problematic, Mustard says. Sites
where sample collection can begin imme-
diately after landing are “going to trump.”
Chen, taking over for Steltzner in lead-
ing the entry, descent, and landing phase
of the mission, hopes he can help by de-
livering the rover to just the right spot.
He is considering two modifications to the
Curiosity system that could improve land-
ing precision. One is a device that would
deploy the entry capsule’s parachute based
on distance to the target, rather than an es-
timate of velocity. This range trigger would
shrink the landing ellipse—where engineers
are confident the rover will end up—from
25 kilometers to 13 kilometers long. Accord-
ing to project manager John McNamee, the
trigger would require changing just a few
lines of code.
Another change, called terrain relative
navigation (TRN), would allow the rover
to land at sites that would otherwise be
too hazardous. It would outfit the descent
module to compare real-time images of the
terrain it was approaching with stored images of the landing site, enabling the sky
crane to avoid regions with too many rocks.
McNamee says the price tag for the TRN is
higher—on the order of $10 million—and
could ripple through the landing system
and affect it in other ways. He wants to be
convinced that the change is absolutely necessary before allowing it.
Scientists at the workshop spoke with
near unanimity, however: The TRN would
open up the most interesting landing sites,
which previous missions had discarded for
safety reasons. Furthermore, the technology
would help guide the subsequent missions
needed to fetch the cache. Steltzner concurs. “We all kinda think that the TRN is the
steering wheel, the headlights,” he says. ■
By John Bohannon
After a string of scandals involving ac- cusations of misconduct and retracted papers, social psychology is engaged in intense self-examination—and the process is turning out to be painful. This week, a global network of nearly
100 researchers unveiled the results of an effort to replicate 27 well-known studies in the
field. In more than a third of the cases, the
result was a complete failure.
As the replicators see it, the failed doovers are a healthy corrective. “Replication
helps us make sure what we think is true
really is true,” says Brent Donnellan, a psychologist at Michigan State University in
East Lansing who has undertaken three
recent replications of studies from other
groups—all of which came out negative. “We
are moving forward as a science,” he says.
But rather than a renaissance, some re-
searchers on the receiving end of this orga-
nized replication effort see an inquisition.
“I feel like a criminal suspect who has no
right to a defense and there is no way to
win,” says psychologist Simone Schnall of
the University of Cambridge in the United
Kingdom, who studies embodied cognition,
the idea that the mind is unconsciously
shaped by bodily movement and the
surrounding environment. Schnall’s 2008
study finding that hand-washing reduced
the severity of moral judgment was one of
those Donnellan could not replicate.
About half of the replications are the
work of Many Labs, a network of about
50 psychologists around the world. The results of their first 13 replications, released
online in November, were greeted with a
collective sigh of relief: Only two failed.
Meanwhile, Many Labs participant Brian
Nosek, a psychologist at the University of
Virginia in Charlottesville, put out a call
for proposals for more replication studies.
After 40 rolled in, he and Daniël Lakens,
a psychologist at Eindhoven University of
Technology in the Netherlands, chose another 14 to repeat.
The output of the new batch of replica-
tions, published alongside the previous 13
this week in an issue of Social Psychology
A 2008 study (right) showing that cleanliness influences moral judgments was not replicated in a new study (left).
Replication effort provokes
praise—and ‘bullying’ charges
Global network fails to confirm 10 of 27 psychology
findings, but some call project an inquisition