Phantom heads and Matroshka

Space science
Spaceflight Vol 53 December 2011
Gathering data on long term radiation exposure
Phantom heads
and Matroshka
by Joel Powell
A team of scientists from Russia, Europe,
enclosed in a white Nomex bag and was
America and Japan have tackled the
velcroed to the starboard bulkhead on the
middeck during the mission.
problem of radiation exposure and protection
head-on, utilising instrumented
The basic instrumented head was
anthropomorphic dummies called ‘phantoms’
provided by the Phantom Laboratory of
that incorporate human body parts.
Salem, New York (after they acquired the
The first of these unique experiments was
flown in August 1989 aboard Space Shuttle
Columbia, and current versions —
codenamed Matroshka — have been
design from Alderson Research
Laboratories). It was loaned to NASA by
the Air Force for the duration of the three
NASA
One of the most vexing problems facing future interplanetary voyagers is long-term
exposure to radiation. Researchers have already determined that space crews face
potentially debilitating doses of radiation during the long journey to Mars, as well as
down on the surface of the red planet.
had dubbed ‘Satan’.
A series of inflight photographs of the
Shuttle flights. Some 120 holes were
Phantom, released by the Johnson Space
Center after the STS-28 flight, were among a
deployed since 2004 aboard the
drilled into the plastic interior of the head
very limited number of photos provided to
International Space Station (ISS).
to accommodate over 400
the public from each classified Defense
Department mission.
Phantom Head
thermoluminescent detector (TLD) chips to
record the radiation dose. Nuclear track
The Phantom Head is probably one of the
detectors were imbedded in the layers of
The eleven pound head was returned to
Phantom Laboratory after each flight for
most unusual experiments ever conducted
the ‘brain’ to register primary radiation
disassembly and readout of the radiation
during a manned spaceflight. Constructed
(heavy ions) and secondaries (particle
dosimeters. The derived data was compared
around a real human skull, the ‘phantom’
was instrumented to measure radiation
fragments created during collisions within
to separate radiation measurements made
on the Shuttle middeck with passive
doses in various depths of simulated human
the particle detectors).
Astronaut Mike Mullane tells a funny
brain tissue.
story about the Phantom in his book Riding
dosimeters.
This experiment validated the use of a
Rockets (Scribner, 2006, p331). At one
‘phantom’ for human tissue equivalent
experiment, formally designated Detailed
point during the STS-36 mission, he
radiation dose measurements. The readings
Supplementary Objective 469, was a joint
NASA and US Department of Defense
slipped into a sleep restraint and two of his
from the instrumented head corresponded
well to the passive dosimeter data from
project that flew on three Space Shuttle
crewmates taped the phantom to the top of
the sleeping bag. The orbital jokesters
missions in 1989-90.
floated up to the flight deck and managed
inside the cabin. Plans were made by NASA
to continue the investigation with a more
Two of the missions, STS-28 and STS-
to scare the wits out of their unsuspecting
elaborate anthropomorphic dummy in the
36, were dedicated DoD flights that flew at
pilot, John Casper, with the phantom they
late 1990s. [1]
The Inflight Radiation Dose Distribution
high inclination and low altitude orbits.
STS-31, the mission that deployed the
Phantom Torso
Hubble Space Telescope, flew in a high
The second space phantom was stowed
altitude, low inclination orbit with DSO 469.
inside the SpaceHab logistics module
The primary source of radiation on the low-
aboard Space Shuttle Discovery in June
altitude flights was galactic cosmic rays
1998. Nicknamed ‘Fred’, the phantom
(GCR), while protons from the inner Van
Allen radiation belt provided the primary
represented the head and torso of a human
being in order to measure the radiation ‘dose
radiation exposure during high altitude
equivalent’ in the internal organs. The
flights.
Phantom remained in space for 9.8 days
Measuring six-by-eight-by-ten inches, the
during the STS-91 mission, including four
Phantom Head was stored in a middeck
days while Discovery was docked to the
locker during ascent and landing. It was
Russian Mir station.
464
Phantom Head
photographed
during the STS-28
mission in 1989.
NASA
Space science
Phantom Torso ‘Fred’ inside the Human Research Facility in the Destiny Laboratory in May 2001.
The Matroshka number — effective
radiation dose as determined by
Matroshka is represented by:
Fred was later deployed on the
measure radiation doses is not new. The US
International Space Station in 2001. The
Air Force designed a plastic replica of a
crew of STS-100 brought the phantom to the
human torso for an orbital space mission in
ISS where it was placed inside one of the
still-empty experiment rack locations in the
May 1965, but the ‘plastinaut’ was lost when
the Atlas launch vehicle exploded shortly
positions inside the torso with
new Destiny laboratory. The torso was
after liftoff.
thermoluminescent and nuclear track
detectors. The instruments yielded good
designed to help estimate the effects of
radiation exposure on the internal organs of
Phantom on Mir
data, revealing that the equivalent doses in
the simulated ‘lungs’, ‘stomach’ and
the body. The phantom was sliced into 34
separate segments, each supplied with
Austrian and Russian researchers devised a
water-filled phantom chamber to record
‘gonads’ was about 90 percent of the dose
passive and active radiation sensors that
radiation dosages on Mir from May 1997 to
on the outside (‘skin’) of the torso. The
gathered data for four months on the station,
February 1999.
anthropomorphic phantom on STS-91 was
sponsored by the National Space
until the phantom was returned to Earth on
0.59 plus-or-minus 0.04 mSv/d
Measurements were made at 59
Development Agency of Japan. [2]
Diagram of the Phantom Head detailing slices
of the simulated brain tissue.
NASA
Shuttle mission STS-105.
The idea of using a phantom torso to
Preflight view of the Phantom Head provided by
JSC.
NASA
The Institute of Biomedical Problems in
Moscow built a 35 cm sphere to house
thermoluminescent radiation detectors
immersed in water. The spherical device was
deployed in the cosmonaut’s personal cabins
(katuyas) in Mir and the Kvant 2 module for a
total of 555 days.
At the altitude of Mir, approximately 380
km, the primary component of the radiation
dose came from galactic cosmic rays, with
a minor component of protons trapped in
the South Atlantic Anomaly region of the
radiation belts. The Spherical Phantom
was intended to measure the depth
distribution (ie, the penetrating power of
the charged particles) in simulated human
tissue.
Matroshka
Faced with the imminent demise of the Mir
station in 2001, ‘Phantom’ researchers in
Russia secured funding to continue their
research on the new Space Station that was
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Space science
Spaceflight Vol 53 December 2011
The Matroshka phantom inside ISS with Expedition 11 crew members Sergei Krikalev (left) and John Phillips.
scheduled to begin assembly flights in 1998.
Russian scientists built another
special carbon-fiber container represents the
astronaut’s spacesuit. The phantom is
NASA
York.
The MTR phantom was installed on the
Spherical Phantom chamber and the
known by the nickname Mr Rando, after the
exterior of the Russian Zvezda module
European Space Agency sponsored a new
trademark name of the torso by its
during an EVA by Expedition 8 astronauts
Phantom Torso from the German DLR
space agency. The experiment was named
manufacturer, Phantom Laboratory of New
Alexander Kaleri and Michael Foale on 26
February 2004.
Matroshka because the sliced layers of the
torso suggested the famous Russian
The encapsulated Matroshka phantom was
mounted on the Zvezda segment to record
EVA-equivalent radiation doses.
ESA
The 1.1 m phantom remained in place as
a sort of figurehead for the ISS for nearly 18
nesting dolls known as matryoshka. The
months until it was brought back inside the
project’s logo features a matryoshka doll
Russian segment during another EVA on 18
with a fiery rocket tail.
The Spherical Phantom (MTR-R) was
August 2005. The sophisticated MTR
phantom was divided into 33 ‘slices’ or
deployed inside the Russian Pirs docking
layers, where 354 TLD detectors were
module beginning in 2004 to gather more
emplaced, along with five nuclear radiation
data on the dose distribution of radiation in
tracking detectors. The Russian Dostel
a ’tissue-equivalent’ apparatus. The
devise measured radiation exposure in the
Russians used a charged particle
telescope (Liulin-5) to measure radiation in
‘brain’. [3]
Using the Matroshka data, scientists
MTR-R, and later installed bubble
calculated the absorbed doses for organs of
detectors to measure doses of neutrons
the body (measured in SI unit micro-Grays)
with the spherical phantom.
and an effective dose measured in the SI
The Matroshka (MTR) phantom torso was
unit micro-Sieverts. These values were
designed for a more ambitious radiation
sampling job — to measure the dose
compared to the data from personal
dosimeters worn by extravehicular
absorbed outside of the Station by
astronauts. The surprising result for
spacewalking astronauts. The torso and
Matroshka researchers was that the EVA
head contains natural bone material, and a
dosimeters over estimated the dose by 2.1
low-density polyurethane material is used to
times, which is good news for spacewalking
simulate the lungs and other organs. A
astronauts.
466
Space science
The phantom remained operational
aboard the ISS until March 2011, when the
radiation sensors were removed for return to
Earth on a departing Soyuz ferry.
Mr Rando had been deployed aboard the
Japanese Kibo laboratory since May 2010 as
part of Italian astronaut Paulo Nespoli’s
MagISStra mission. As a measure of its
scientific significance, Matroshka has been
the longest running radiation investigation on
the Station, gathering data for seven straight
years.
The spherical phantom was re-activated
on the ISS in May 2011. It was operated with
new Canadian-built bubble detectors
(dosimeters) for the study of neutron
exposure in humans. The Russian
designation for this new application is MTRRO 3.
Measuring Mars
The average radiation dose at Mars, as
measured by the MARIE radiation instrument
on the Mars Odyssey orbiter (before the
Preparations to take Matroshka phantom outside the ISS during EVA in February 2004.
NASA
instrument failed prematurely in 2003) is
twice that measured on the ISS in Earth
orbit. [4]
Daunted by the MARIE findings, NASA’s
mission directorate in Washington
authorised the Radiation Assessment
Detector (RAD) to fly on the new Mars
Science Laboratory (the Curiosity rover) in
November 2011. The instrument will
measure charged particle fluxes on the
voyage to Mars, and will perform the first
radiation survey on the surface of Mars.
The ultimate goal of RAD is to determine
how much radiation shielding will be
necessary on a human mission to the red
planet. The RAD experiment is a joint
undertaking of the Southwest Research
Institute in Boulder, Colorado, and their
partners at Christian Albrechts University in
Kiel, Germany. [5]
Future exploration
Inside the head of Mr Rando.
Analysis of Matroshka data continues in
as early as the 2020s.
The data from Matroshka will be used to
also be used to validate estimates of how
much shielding will be required on the
laboratories around the world. The radiation
calculate the maximum permissible
spacecraft.
studies have been motivated by the stated
goal of several national space agencies to
radiation doses for the human crews in
What is up next for the Matroshka
order to determine a reliable cancer risk
phantom? According to DLR, the facility
explore the Moon, asteroids and planet Mars
forecast for the astronauts. The data will
will be deployed once again outside the
ISS in the near future. The research group
References
1. A. Konradi, W. Atwell et al., “Low Earth Orbit
Radiation Dose Distribution in a Phantom
Head”, Nuclear Tracks Radiation Applied
Instrumentation Part D, 20, pp. 49-54, 1992.
2. Hiroshi Yasuda, Guantam D. Badher et al.,
“Effective Dose Equivalent on the Ninth
Shuttle-Mir Mission (STS-91)”, Radiation
Research, 154, p.705, 2000.
3. Gunther Reitz, Thomas Berger et al.,
wishes to obtain another data set for EVA
“Reducing Radiation Risk in Space: The
Matroshka Project”, ESA Bulletin 141,
February 2010.
4. Kerry T. Lee, “Martian Radiation
Environment Experiment (MARIE)”,
dissertation for University of Houston, 2006.
5. Greg Webster, “Sensor on Mars Rover to
Measure Radiation Environment”,
www.jpl.nasa.gov/news, 9 November 2010.
exposure during the new solar cycle, to
compare with the first deployment in 20042005.
With its emphasis on protecting future
exploration crews, perhaps the Matroshka
experiment will one day share responsibility
for the success of the first human deep
space expeditions.
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