Status Report

Statement By Laurence R. Young – House Science Committee Hearing: “Perspectives on the President’s Vision for Space Exploration”

By SpaceRef Editor
March 10, 2004
Filed under , ,

Testimony to US House of Representatives, Committee on Science

Hearing on Perspectives on the President’s Vision for Space Exploration

Washington D.C. March 10, 2004

Laurence R. Young, Sc.D.

Apollo Program Professor of Astronautics Massachusetts Institute of Technology

Professor of Health Sciences and Technology, Harvard-MIT.

Outline of responses to key questions posed by the Committee:.

Q.1.What are the most significant human physiology challenges? How daunting?
When will they be resolved? How much research has been done and where was it

A.1 Bone loss, muscle loss, cardiovascular decondtioning and neurovestibular alterations
are all known challenges. The longer the space flight the more serious the after-effects of
weightlessness. With insufficient countermeasures the long duration flight using
conventional propulsion (9 months to Mars, month to a year on the surface at 3/8 g, and
6-9 months back to Earth), the microgravity effects will be very deleterious. Current
countermeasures (aerobic and resistive exercise as in ISS), although inefficient and
onerous for some astronauts, are reasonably effective against some of the muscle and
cardiovascular losses – but have only limited effectiveness in countering the full range of
dangerous bone weakening. Bone loss and the related risk of fracture remains the most
serious unsolved threat. Progress in treating demineralization is being made with use of
drugs (bis-phosphonates). Cardiovascular deconditioning and the associated post-flight
orthostatic hypotension may also be combated with drugs (mydodrine) as well as fluid
loading and aerobic exercise. The effectiveness of these drugs for use in space and
following return is only now being determined. A protective suit can also mitigate the
problem of orthostatic hypotension to some extent. It remains to be determined if some
such suit will be needed or provided for landing on the moon or Mars. Neurovestibular
problems can affect balance and locomotion for a considerable time after return to earth.
This too, along with motion sickness, can threaten astronaut safety and comfort on
arrival at Mars unless effective countermeasures are employed. Overall, the current suite
of exercise countermeasures, relying primarily on treadmill, resistance devices, is
unreliable, time consuming, and inadequate by itself to assure the sufficient physical
conditioning of astronauts going to Mars.

Radiation remains the most vexing and difficult issue. Both increases in the likelihood of
cancer and possible acute radiation sickness are major concerns for any extended flights
outside the protection of Earth’s magnetic field. During solar flare periods astronauts
could retreat to a small shelter to avoid the potentially high level proton storms Galactic
cosmic radiation, consists of omnidirectional fluxes of particles covering a wide range of
energies. High energy charged particles in the constant cosmic radiation are
considerably more difficult to protect against. Conventional shielding against them only makes matter worse by the secondary emission of further damaging radiation. Both the
flux of these particles and their impact on organs are being measured by a variety of
dosimeters currently aboard ISS. The very important issue of the relative biological
effectiveness of these heavy charged particles is also under investigation, making use of
the new NASA Space Radiation Facility at the Brookhaven National Laboratory. The
Alpha Magnetic Spectrometer aboard ISS should add highly accurate determination of
the flux of galactic radiation, by extrapolation from its measurements made on the Space
Station. Some progress in drug protection against the radiation threat is currently being
made but more effort in that direction is required. Magnetic shielding, long considered
desirable, may also be moving toward a practical implementation using superconducting
magnet technology .

One promising approach to the weightlessness issue is the well known but never
implemented artificial gravity approach, to be discussed later. Both the microgravity and
radiation threats, of course, are reduced by shortening the transit time to several months
and using the local soil for added shielding on the surface of the moon or Mars. The
transit time for propulsion using conventional bi-propellant rockets is essentially
determined by orbital mechanics as one coasts towards Mars. Advanced technology
propulsion could shorten the voyage and mitigate the threats, as well as ease the serious
psycho-social challenge of small groups working and living in isolation for long periods.
Much of the recent bioastronautics research has been conducted at universities by
countermeasure development teams of university and government laboratories under the
leadership and sponsorship of the National Space Biomedical Research Institute and at
JSC. A ‘Critical Path Roadmap” and associated high priority research questions has
been developed and maintained by JSC and NSBRI – and should guide the selection of
peer reviewed research proposals. This Roadmap is about to be reviewed by a panel
under the direction of the three Academies: NAS, NAE and IOM.

Q.2 How can research aboard ISS contribute to solving these problems? What kinds
of experiments and additional equipment are needed? How long will it take?

A.2 The ISS is potentially the ideal laboratory for research into all of the microgravity
related issues challenging long duration exploration. It has not yet been used effectively
however, for several reasons. While under construction, and with a limited crew of three
(now2), no time is available for intense human research. Only one of the two Human
Research Facility racks is onboard, and sample return is currently nearly non-existent.
The limited results to date should not be taken as predictive of the potential benefits of
the fully equipped and staffed ISS, any more than the initial flawed HST could have been
used to predict its current string of successes.

The keys to fulfilling the potential of ISS in the bioastronautics areas are:

1. Support of peer reviewed, mission oriented flight experiments directed at
solution of the key bioastronautcs challenges.

2. Provision of a full resident crew of 6 or 7, including astronauts trained and
capable of doing biomedical studies and serving as test subjects.

3. Installation and resupply of the key biomedical equipment, beginning with the
Human Research Facility Rack 2, and enabling the important additions in the JEM and
Columbus to be added to the ISS.

4. Timely, or even accelerated, launching of the Centrifuge Accommodation
Module (CAM) and performance of key experiments on animals at various g-levels. (The
scientifically important research into the influence of partial gravity on animals and cells
is also fundamental to understanding the problem of human deconditioning and survival
in 0-g, on the moon or on Mars.) The utilization of the CAM will, of course, require the
regular upload and download of research specimens – even after discontinuation of
Shuttle flights.

5. Utilization of the ISS as a test-bed for technology development for advanced
life support systems. Testing and evaluation of full or partially closed life support
systems, essential to any long duration mission to the moon or Mars, will be best
accomplished on the ISS. If successful these advanced life support systems could then be
incorporated into the infrastructure of the ISS itself, reducing operational costs and
permitting larger and longer crew presence.

Finally, the most important piece of additional equipment to meet the research goals is a
short radius human centrifuge for the study of intermittent artificial gravity inside the
ISS. Ground studies already underway will determine the potential of artificial gravity
for preventing all of the microgravity related deconditioning issues. Although early
positive results will guide missions planners regarding artificial gravity, only flight tests
with numerous (tens) of astronauts for extended periods (several months) will allow this
‘universal antidote” to be proven and applied to a Mars mission in conjunction with
other countermeasures. Design studies of a moderate radius (56m) spacecraft structure,
rotating at 4 rpm to provide 1-g of artificial gravity, are encouraging and the concept
appears practical.

Q. 3 How would the research budget and number of astronauts aboard station have
to be changed to accomplish the research agenda?

A.3 The proposed research budget for Biological /Physical Sciences Research ($492
Million for FY 2005) represents a substantial increase. However, to go along with an
increase to 6 or 7 crewmembers, the capability of conducting many more in-flight
experiments, and the need for a human centrifuge on the ISS, this budget will need to
increased even further. I am not prepared to speculate on the desirable level. Among the
substantial number of ground research studies submitted to NSBRI and to NASA are
numbers of potentially valuable and relevant flight experiments, each of which is costly.
Since there have been very few flight biomedical experiments since Neurolab and STS-95,
a substantial queue of accepted peer reviewed investigations already exists. Some
worthwhile studies have already been ‘deselected” for lack of flight opportunities or

Q.4 How long will the ISS have to remain in operation to produce meaningful flight

A.4 Because most of the human physiology experiments require long duration
exposure to weightlessness and evaluation of potential countermeasures, the process
of accumulating sufficient data and exploring the relevant variables is very time
consuming. Initial results for countermeasure evaluation, for example, might only
begin to be accumulated after four sessions of 4-6 months each. Early positive results
would obviously influence both Mars mission designs and even continuing ISS crew
health protection. To reach a valid scientific conclusion about particular protocols
however, fuller exploration might take 8-10 test missions, or up to 5 years to finish.
Finally, it seems prudent to complete a full-length on-orbit simulation of at least the
mission to Mars, if not the entire round trip, before embarking on that voyage of
exploration. Obviously a lunar base could form a key portion of this simulation,
along with the ISS.

Beyond the immediate use of the ISS to answer some of the more pressing issues in
human physiology associated with the Vision for Space Exploration, is the larger
question of the continued need for a microgravity laboratory for science and
technology. The proposal to limit ISS research to the impact of space on human
health and to end support for other important microgravity science and space
technology seems short sighted. There will remain numerous important questions, in
fundamental biology and physics, in the behavior of fluids and combustion, in
materials and crystal growth that can only be answered in orbit. If the ISS were
allowed to end its useful life prematurely we would only hear a strong cry for its
replacement. I strongly believe in the scientific and technical value of a ‘permanent
presence in space”.

Additional Comments:

Education and Outreach:

It has often been claimed that the human space serves to motivate students and
teachers to emphasize science and mathematics in the educational process. I can
state from personal experience with some of the country’s best young minds that this
is certainly true. The excitement of human space flight and the recognition of the
daunting nature of some of the tasks invigorate the very students we most need to
continue to drive the science and technology engine of our society. The national
Space Grant program, for example, regularly contributes to the education of
thousands of youngsters who have ‘seem the stars” and remain committed to the
space program. The proposed Moon/Mars mission will only expand this level of

SpaceRef staff editor.