ROOM
73
Astronautics
Sample returnmissions have
enabled extraordinary discoveries
missions have enabled extraordinary discoveries
that fundamentally improved our understanding of
the Moon with the Apollo missions and their 382 kg
of lunar rocks; of comets with the Stardust mission;
and of asteroids with the Hayabusa mission.
Until now, sample return missions have been
led mostly by NASA in the US, by Roscosmos in
Russia and by JAXA in Japan. Europe is a main
actor in space exploration but has lacked the goal
of claiming part of the samples brought back by
these missions.
One possible explanation is that there is
currently no dedicated curation facility for pristine
extra-terrestrial samples on European territory,
similar to those at NASA’s Johnson Space Center,
Houston, or at JAXA, Sagamihara, Japan.
Unrestricted or restricted samples
The two facilities cited above have been
designed to keep the samples protected against
a range of contaminants which may affect the
scientific analysis of returned samples. The main
requirements rely on technologies routinely
used in cleanroom environments (i.e., by keeping
the rooms under positive pressure, with a range
of High Efficiency Particulate Air (HEPA) and
Ultra-Low Penetration Air (ULPA) filters to scrub
the air of any particles) and on the rigorous
selection of materials allowed to be in contact
with the samples.
Samples are typically kept under an inert
atmosphere, usually dry nitrogen gas. However, all
the samples which have been returned to Earth so
far are from celestial bodies known to be devoid of
any potential present or past form of life.
The Committee on Space Research (COSPAR)
[1] defines five planetary protection categories
with subcategories dependent on the target of the
mission and the type of mission (fly-by, orbiter or
lander). Category I missions do not have planetary
protection requirements, e.g., for missions to
undifferentiated, metamorphosed asteroids or Io.
Category V missions include the most stringent
planetary protection requirements. All missions
which will return extra-terrestrial samples to Earth
for further analysis belong to category V. Dependent
on the origin of the extra-terrestrial material, a
category V mission can be an unrestricted Earth
return mission (e.g., in the case of samples from the
Moon) or restricted Earth return mission (e.g., in the
case of samples fromMars or Europa).
There are no special requirements for sample
containment for unrestricted missions. However,
for restricted missions, where there is thought
to be a chance of life, the requirements include
absolute prohibition of destructive impact upon
return, containment of all returned hardware
which directly contacted the target body, and
containment of any unsterilized sample returned
to Earth.
Considering the Mars sample return missions
planned for the future, it is imperative to start
now to plan a facility able to receive and host
these potentially biohazardous samples, especially
knowing that the design, construction and
certification of such a facility can take a decade to
be up and running [2].
Study and long-term curation of extra-
terrestrial samples, either unrestricted or
restricted, require the samples to be protected
Aurore Hutzler in front
of an X-ray
diffractometer inside
JAXA’s Hayabusa-
returned sample curation
facility in Japan. The lab
coat (a class 1,000 gown)
is specifically designed to
reduce contamination
from workers.
NASA’s OSIRIS-REx
spacecraft during its
preparation for
encapsulation in its
payload fairing prior to
launch in September
2016. It is the first US
mission to sample an
asteroid, retrieve at least
two ounces of surface
material and return it to
Earth for study.
NASA/Glenn Benson
Ferrière/NHMV
