Meet: Charles M. Oman, Ph.D.
Roles of Visual Cues in Microgravity Spatial Orientation
Photo: MIT News Office
What I do:
I'm a research engineer and neuroscientist at the Massachusetts Institute
of Technology in Boston. Neurolab is my sixth Spacelab mission. For the
past decade I have been Director of the Man Vehicle Laboratory in MIT's
Center for Space Research.
Our group studies the physiological and cognitive limitations of humans
in aircraft and spacecraft, and tries to develop new ways of improving
human-vehicle effectiveness and safety. Some of what we do also has medical
applications. We take an interdisciplinary approach, utilizing techniques
from manual and supervisory control theory, estimation, signal processing,
biomechanics; cognitive, computational and physiological neuroscience;
sensory-motor physiology, human factors, and biostatistics.
Many of our students are engineers from the Department of Aeronautics
and Astronautics. Some are from other departments, including the Harvard-MIT
Division of Health Sciences and Technology, where I have a joint appointment.
This year, I've been teaching a seminar on the case for human planetary
exploration. I also lead a new multi-investigator neurovestibular research
program in the National Space Biomedical Research Institute.
For many years, I've been fascinated by human vision and the inner ear
balance system, and wondered why people sometimes experience disorientation
and nausea when flying in air- and spacecraft.
My Career Journey
All my life I have been fascinated by airplanes and space travel. Growing
up in a New York suburb in the fifties, I built and flew model planes
and rockets. I remember back in second grade, crayoning what the interior
of a space station should be like instead doing of the assignment. My
heroes then were science fiction astronauts Tom Corbett and Captain Video.
No humans had actually flown in space yet, but the prospect was exciting.
When I watched Sputnik cross the night sky, it somehow seemed obvious
that people would follow, and that human destiny included voyaging to
the planets and perhaps beyond. Thirty years later, when my students and
I look up at the Mir station, many of us still believe our ultimate destiny
is pretty obvious.
My thoughts were so much in the sky that I wasn't a good student at
first. But in my teens I went to a superb high school in New Jersey called
Lawrenceville. I got a broad education from some wonderful teachers, who
taught me to connect my dreams with a disciplined life. Both parents understood
when I went on to Princeton and decided to major in aerospace engineering.
Princeton was an exciting place where I really learned how airplanes and
rockets fly. My junior year I got a summer job at the University's flight
research hangar. Building esoteric sailwings and hovercraft, I discovered
I had a flair for research. I learned to fly real airplanes, and ran the
I think my scientific interest in the subject of motion sickness probably
began back then while learning to fly aerobatics. If motion sickness is
caused by motion, how come when my instructor has the controls, I get
queasy, but when I do the same loops and spins, I am immune ?
When I finished Princeton, Apollo was just getting underway, and MIT was
designing the guidance system, so I decided to go there for graduate school.
Professors Larry Young and Y.T. Li had recently founded the Man Vehicle
Laboratory, and Larry gave me a Research Assistantship. My first job was
to interface a head tracker to a desktop computer display. It was one
of the first interactive virtual reality systems ever built. But the technology
was pretty limiting in those days, so I left computer graphics, and took
courses in physiology and bioengineering.
Larry was working on the vestibular organs of the inner ear, the accelerometers
in the human biological inertial guidance system, and his enthusiasm was
infectious. He challenged me to explain the relationship between what
was physically happening in the inner ear, and the resulting compensatory
eye movements and motion sensations. We used some simple differential
equations to model vestibular adaptation. Of course it was an oversimplification,
as many models are. People are still struggling to do it properly. But
ours explained some previously unexplained things, and became widely used.
Meanwhile, another MIT faculty mentor, Larry Frishkopf , got me interested
in how hair cells work in the lateral line organs of aquatic animals.
My Doctoral thesis (1972) was on both lateral line and vestibular organs,
strongly influenced by both Larrys.
I joined the MIT faculty in 1972. Larry Frishkopf and I continued to work
together for several years. In my thesis, I had argued that the semicircular
canal fluid movement must be far smaller than previously thought. We set
out to prove it by studying the inner ear of a big fish, the skate. It
was difficult to keep skates in Cambridge, so for several summers in the
early seventies, we'd truck our entire lab down to Cape Cod to the Marine
Biological Lab in Woods Hole.
Our experiments there required careful microdissection, luck, and sometimes
ran all night. Next day we'd give up and go to sleep - or go out sailing.
I have been a sailor all my life, and kept a racing dinghy on the beach
nearby. Our lab had a superb view of the Vineyard Sound, so sometimes
the temptation to get out on the water was overwhelming. Often I'd discover
Steve Highstein - now also a Principal Investigator on Neurolab - already
there, rigging his boat. Steve had the same problem: a difficult preparation,
and a lab with a picture window. Sailing out, we would wave to our more
industrious colleagues ashore, but neither of us felt too guilty. Truth
be told, in those summers I was away from the lab for days at a time,
since I was involved in big boat one design and ocean racing.
I didn't consider it professionally relevant experience at the time,
but in a way it was. In storms offshore, I'd wonder how come taking the
helm wasn't the instant cure for seasickness as it was when flying. Also
it was personally significant: racing on San Francisco Bay in '73, I met
my wife Cherry.
Each Fall, we'd move the lab back to Boston, and I'd rejoin MVL. I did
some human factors research on recency effects on pilot flying skills,
but also kept working on the fluid mechanics of the inner ear, collaborating
via P-mail with Ian Curthoys in Australia. Larry Young and I looked for
better ways to automate the analysis of eye movements. Johannes Dichgans
came to Boston to join us in a study of how moving visual scenes produced
illusory self-motion in flight simulators. Otmar Bock - now a Neurolab
PI - arrived from Germany for a post-doc, and we decided to study adaptation
to left-right vision reversing prism goggles. Otmar and I came to work
each morning, and in the name of science made each other motion sick.
We made the interesting discovery that visually induced self-motion
illusion reverses within just a few hours after you don the goggles. We
also saw patterns in the time course of nausea development and remission.
Pursuing this, I visited Jim Reason at the University of Manchester, who
had developed a widely known version of the sensory conflict theory for
motion sickness. I recast Jim's theory in mathematical form, and extended
it so that it accounted for my pilot/passenger paradoxes, and the time
course of symptoms. There were some practical implications for sailors.
Seasickness had contributed to the deaths of many yachtsmen in the '79
Fastnet Race gale, so I began writing for sailing magazines, and lecturing
on seasickness prevention at Safety-at-Sea seminars.
About that time, astronaut Owen Garriott told us the details of his experience
with space sickness on Skylab. The Soviets had been blaming space sickness
on fluid shift, but space sickness hadn't been a problem earlier in the
small spacecraft used in the US program. Early Cosmonauts had the luxury
of big vehicles. It made sense to think that space sickness - like ordinary
motion sickness - originated when people were able to get out of their seats,
move about, and experience conflicting cues from their eyes, ears, and joints
as they moved around.
The Shuttle was going to be the biggest spacecraft yet, and we expected
sickness would be a problem. So in 1976, Larry Young and I wrote a proposal
with our Canadian friends Doug Watt and Ken Money to develop a family
of vestibular experiments for the shuttle Spacelab module. Our proposal
was accepted, but was six long years till the Spacelab was ready to go.
The delays gave us time to try out our experiments aboard NASA's Vomit
Comet parabolic flight airplane. We learned firsthand about visual reorientation
illusions, and trained our astronaut subjects to look for them in orbit.
When the shuttle began flying in 1981, space sickness suddenly became
a well publicized problem. Garry Trudeau's Doonsbury wagged that it should
be measured in units called "Garns" - to immortalize Utah Senator Jake
Garn, who was honest and admitted he was sick during virtually his entire
By 1983, Spacelab was ready, and our stuff finally got to go. Over the
next decade, we flew on four different missions. Many of the Spacelabs
were interdisciplinary, and half the fun was getting to know the other
PIs and something about their science. Our crews were terrific, good scientists
and fun people. Byron Lichtenberg, one of our students, was selected to
fly on Spacelab 1 as America's first Payload Specialist.
Larry Young did a superb job leading the experiment team through three
missions. On the fourth, he changed hats, and became Alternate Payload
Specialist. Our experiments didn't always turn out as we'd hoped - that's
the way it is in science - but we got preliminary answers to several important
questions that helped frame the research agenda for this decade.
We found that gravireceptor thresholds and perception in darkness
didn't change as much in orbit as some thought, but that the dominant
time constant of the head-eye stabilization reflex did. Crewmembers became
more dependent on visual and tactile cues to their self-rotation. Space
sickness was triggered by head movements, but the visual reorientation
illusions we'd seen in parabolic flight also clearly contributed. There
was a simple solution: whenever anyone felt queasy, everyone on board
should remain visually upright. After return to Earth, tilting the head
created the illusion of moving sideways (due to what we called otolith
tilt-translation reinterpretation) and caused earth readaptation sickness.
To follow up on the eye movement story, I joined a group developing some
more sophisticated rotating chair experiments. The team was ably led by
Mill Reschke, and it brought together many experienced university and NASA
investigators. It was a simulating and fun group to work with. Our experiments
- called the Microgravity Vestibular Investigations, flew in 1992. Some
of the Neurolab vestibular team's experiments evolved from results of this
No drug has yet been found which consistently prevents space sickness
(or motion sickness on earth, for that matter) so the problem still remains
with us. However, giving space sick crewmembers a shot of a conventional
antihistamine anti motion sickness drug called promethazine seems to help.
The injection is into muscle, so unfortunately it does cause a sore spot.
Neurolab - and the future
To pursue role of vision on orientation in zero-g, I proposed a follow
on experiment in the mid eighties using a special slide viewer. This was
approved, but indefinitely postponed after the Challenger explosion. However
a decade later, NASA began to develop a new virtual reality graphics workstation
for the Shuttle and Space Station. It was the ideal research tool for
what we wanted to do. With help from Ian Howard and Ted Carpenter-Smith,
I revised the proposal and submitted it for Neurolab. Details on what
we're up to are available on the Neurolab web site.
Andy Beall joined us for Neurolab, and working through the new National
Space Biomedical Research Insitute, we are starting to apply our work
to preflight orientation training. With Neurolab colleague Alain Berthoz,
we are also developing a new international virtual reality experiment
for Space Station.
I have given up flying so I can devote more time to family - like sailing
with my kids. But the pilot's role in the aircraft cockpit is changing
dramatically, and my interest in cockpit human factors research remains
strong. In recent years, I have collaborated with colleagues at DOT's
nearby Volpe Research Center to develop concepts for a new generation
of vertical navigation and GPS instrument approach displays. But that
is a another story.
Likes/Dislikes about career
I consider myself lucky to have been able to combine my passions for
aerospace engineering and neuroscience, and make a living at it at a place
like MIT, amongst world class students and colleagues. I truly look forward
to going to work each day. My wife and two children have been very understanding
of my itinerant lifestyle, and more lengthy absences when a mission goes
Developing an experiment, trying it in parabolic flight, training a
crew, and working with them from Houston during the mission is a fascinating
experience. But a career in space life sciences involves professional
risk: Each experiment requires years of effort, and sometimes the data
you get is disappointing, or the flight is delayed or cancelled. While
the space station is under construction, the opportunity to do experiments
will be rather limited. It is great to see so many younger people interested
in space life sciences, but if you are interested in an academic career,
I think you are well advised to get established in mainstream neuroscience
or engineering first.
There isn't quite the same excitement about human space exploration
now as there was in the early days of the program. NASA suffers from many
of the problems of a mature organization. However, I remain optimistic.
All this could change as soon as the costs for getting into orbit are
lowered, and if interest in the search for the origins of life galvanizes
into a human expedition to Mars or Europa. All of us in the game have
the satisfaction of working on something we know will be important in
the long run.
Several people from your MIT laboratory have become astronauts. You
were on the Neurolab Payload Specialist Selection Committee. If a person
is interested in becoming an astronaut, what is your advice?
Learn as much as you can about the space program, and find out what
an astronaut's job really involves. Astronauts get to do many exciting
things, but much of their lives are spent away from home, sitting in technical
meetings. And there are the risks of riding the rocket. Get an application
form from NASA, and see what the academic, medical and professional experience
requirements are. Become a student member of one of the space or professional
societies. You can usually find a meeting where you'll have the opportunity
to meet some astronauts and talk.
Choose an area of science or technology that truly interests you, and
which you think will be important to NASA ten years from now. Become an
expert at that. If you're really interested in what you’re doing, working
long hours is fun, and you can focus all your energy on being as good
as you can be. If you happen not to be selected, you'll have many other
attractive career options.
Try to develop an interdisciplinary perspective, and some practical
lab and computer skills. Get experience working in several different disciplines
and as a member of a team, perhaps at a NASA Center. Of the four or five
from our group who have been selected, most of them fit a "T" model pretty
well: broad in terms of interests, experience and abilities, but deep
in their specialty. And they all have a lively sense of humor.
One last thought: if you make the first cut, but then aren't chosen,
be patient and persistent. Believe in yourself. Many astronauts I know
have applied several times.