Emerging Risk Assessment and Management Controversies
in the Mars Sample Return

presented to:

27th Annual Natural Hazards Research and Applications Workshop
Boulder, CO, 14-17 July 2002.


Christine M. Rodrigue

Professor and Chair
Department of Geography
California State University
Long Beach, CA 90840-1101
(562) 985-4895 or -4977 (fax -8993)


For a number of years, I have investigated the risk assessment and risk management controversy surrounding NASA's use of plutonium-238 dioxide radioisotope thermoelectric generators (RTGs) and radioisotope thermal generators (RHUs) (Rodrigue 2001a, 2001b, 2001c). RTGs are used to power spacecraft instruments for such outer solar system missions as the Cassini- Huygens mission to Saturn and Titan and the Galileo mission to Jupiter. RHUs are used to provide heat to keep spacecraft instruments operating in the deep cold of outer solar system space. RTGs and RHUs generate heat through the alpha radiation given off by the Pu-dioxide as it decays (JPL n.d.).

In the case of Cassini-Huygens, NASA's decision to utilize a Venus-Venus- Earth-Jupiter gravitational assist trajectory (VVEJGA) increased the controversy. The gravitational assists increase the speed of the spacecraft and substantially shorten the length of the cruise to Saturn, 1.4 billion km from the sun. They work by bringing a spacecraft close to a planet in the direction of the planet's revolution, in order to allow an exchange of angular momentum between them. In assessing the risks posed by Cassini- Huygens, then, attention focussed on the pre-launch handling of the RTGs and RHUs, mishaps during launch, and accidents during the flyby which could cause the spacecraft to break up and explode in the earth's atmosphere.

Risk assessment done for NASA concluded that the risks involved were trivial, with extremely small probabilities of accidents releasing Pu into the earth's atmosphere and minor health effects in the event a worst-case accident did take place. All estimates for any of the pre-launch or launch phases fell below one health effect or surplus cancer death over five decades, with a 1% probability of from 0.55-1.50 surplus deaths being exceeded. For the flyby manoeuvre, final estimates of expected health effects were 120, with a 1% probability of 450 surplus deaths being exceeded (NASA 1997: 2.20-2.23).

Opponents claimed that NASA and the media were covering up the extent of the risk. They stated an accident could give every person on Earth lung cancer and directly cause the deaths of anywhere from 200,000 to 40 million people (Kaku 1997; Grossman 1997). Using e-mail, listservers, and newsgroups, as well as web pages and articles and editorials in print media, a handful of people orchestrated a large political opposition movement to pressure Congress and the President to cancel the launch and later the Earth gravity- assist manoeuvre. This movement was ultimately able to attract the attention of broadcast media through demonstrations and other dramatic confrontations. They did not ultimately succeed in either canceling the launch or aborting the Earth flyby, they did succeed in making the use of RTGs and RHUs controversial (Golombek 2001).

Internet organizing was able to circumvent the many filters and obstacles normally encountered in trying to publicize a cause through conventional print and broadcast media (see, e.g., Bagdikian 1992; Herman and Chomsky 1988; Lee and Solomon 1991). Internet organizing is able to take advantage of chain-mail mathematics, that is, the propagation of a few people's messages through recipients' forward buttons to an exponentially expanding audience. A literal handful of people was able to reach an audience of a size and spatial scope normally only the purview of major media conglomerates. In its capacity of distributing agenda-setting power more widely through society, the Internet is a democratizing influence; it equally well empowers demogoguery. Risk management policy-makers will be hearing from more people more often and trying to discern the extent of the emotions' and arguments' appeal among their constituencies.

I am now following another emerging risk assessment and management controversy related to the space program: The Mars Sample Return Lander. The purpose of this mission is to collect samples of Martian soil and rocks for return to Earth for detailed study of their elemental, isotopic, and minerological composition, as well as evidence of past climates and geomorphological processes they may contain. The samples will be studied for signs of life, past or present. Return to Earth is highly sought, given the ambiguity affecting the robotic tests on the 1976 Viking lander (NAS 1996). This mission, if approved, could have its first launch as early as October of 2011 and return to Earth in September of 2014 (JPL 2002a). More probably, it will launch in 2014 and again in 2016 (JPL 2002b; Savage 2000).

This mission has already raised three distinct risk assessment and management controversies . The first of these is similar to the Cassini controversy: The mission will almost certainly involve the use of RTGs, because of the need for absolutely reliable power output for months on Mars. Because of this, it can be expected that the same parties that orchestrated the anti-Cassini movement will begin to organize against the MSRL. At least one group is already keeping an eye on the mission, i.e., the Global Network against Weapons and Nuclear Power in Space (no date).

A second controversy has already erupted, complete with activist web page: http://www.icamsr.org. The concern of this oppositional strand is biocontamination of Earth by the Mars sample returned to Earth. The argument is that there is a non-zero probability of some kind of microbial life existing now on Mars which could be picked up by the MSRL and launched back to Earth. If the recovery of the spacecraft went awry, these organisms could conceivably be released into the Earth environment. Should that happen, there is again a very tiny but non-zero probability that the Martian organisms could somehow adapt to Earth conditions and host organisms and generate a pandemic (ICAMSR 2002).

A third controversy is building within the scientific communities from which the principal investigators of the various investigations on the MSRL will be drawn, pitting geoscientists against bioscientists (Dawson 2001). The bioscientists, hopeful that some sort of Martian life would have survived the trip to Earth, would like to quarantine the samples as long as possible to give Martian life a chance to express itself in some measurable fashion. The geoscientists, while acknowledging the faint possibility of Martian life surviving a ride back to Earth and the appropriateness of a quarantine period, would like the samples speedily sterilized and distributed for their investigations.

Some of these controversies will pit conventional risk assessment expertise against lay activists. Lay activists enjoy the advantage of not needing to do professional risk assessment: They need only question the legitimacy of expertise to be successful at generating opposition to the mission (the RTG and biocontamination controversies). Other controversies will entail differences of opinion and priorities within the scientific community, notably the geoscience vs. bioscience division, but this kind of conflict is also seen in professional debates about the possibility of biocontamination and the efficacy of Biosafety Level 4 measures against it (Wood 2002). I plan to follow these through the Internet, where the bulk of organizing can be predicted to take place.

Data and methods are still under development. Likely sources of data will be webpages for ICAMSR and the Global Network against Weapons and Nuclear Power in Space and similar oppositional groups that emerge. Additionally, I'll track discussion online through UseNet and newspaper coverage. These materials will be subjected to literature content analysis, similar to my Cassini and other projects on media and hazard. One of the avenues I regretted not pursuing with the Cassini project was interviews of elected risk management policymakers, notably senators and congressional representatives and possibly risk assessment scientists under contract to NASA for environmental impact review. Including such sources would enable me to include an analysis of the impacts of activism on the risk assessment and risk management dialogue.



Bagdikian, Ben H. 1992. The media monopolgy, 4th ed. Boston: Beacon Press.

Dawson, Sandra. 2001. Personal communication. Ms. Dawson is JPL Launch Approval Engineer (26 November).

Global Network against Weapons and Nuclear Power in Space. No date. Future plutonium missions. Available at: http://www.globenet.free-online.co.uk/future.htm

Golombek, J. 2001. Relative roles of robots and humans in the exploration of Mars. Presentation to the Meeting on Humans and the Exploration of Mars, Goddard Space Flight Center (January 24-25). Available at: http://www.lpi.usra.edu/publications/reports/CB-1089/golombek.pdf.

Grossman, Karl. 1997. The risk of Cassini probe plutonium. Christian Science Monitor (October 10). Available at: http://www.csmonitor.com/durable/1997/10/10/opin/opin.1.html.

Herman, Edward S., and Noam Chomsky. (1988). Manufacturing consent: The political economy of the mass media. New York: Pantheon Books.

International Committee Against Mars Sample Return (ICAMSR). 2002. http://www.icamsr.org.

Jet Propulsion Lab (JPL). No date. Spacecraft power for NASA missions. Available at: http://spacepwr.jpl.nasa.gov/.

________. 2002a. Solar system exploration missions to Mars: Mars Sample Return Lander (9 May). Available at: http://sse.jpl.nasa.gov/missions/mars_missns/mars-srl.html.

________. 2002b. Mars exploration: 2005 and beyond (3 April). Available at: http://mars.jpl.nasa.gov/missions/future/2005-plus.html.

Kaku, Michio. 1997. A scientific critique of the accident risks from the Cassini space mission. The Real News Page (August).

Lee, Martin A., and Norman Solomon. 1991. Unreliable sources: A guide to detecting bias in news media. New York: Lyle Stuart, Carol Publishing Group.

National Academy of Sciences (NAS). 1996. On NASA Mars Sample-Return mission options. NAS Space Studies Board Report. Washington, DC: National Academy Press.

National Aeronautics and Space Administration (NASA). 1997. Final Supplemental Environmental Impact Statement for the Cassini Mission. NASA Office of Space Science. Available at: http://www.jpl.nasa.gov/cassini/english/msnsafe/.

Rodrigue, C.M. 2001a. Internet media in technological risk amplification: Plutonium on board the Cassini-Huygens spacecraft. Risk: Health, Safety & Environment 12, 3/4 (Fall): 221-254.

________. 2001b. Impact of Internet media in risk debates: The controversies over the Cassini- Huygens mission and the Anaheim-Hills, California, landslide. The Australian Journal of Emergency Management 16, 1 (Autumn): 53-61. Available at: : http://www.ema.gov.au/5viturallibrary/pdgs/vol16no1/rodrigue.pdf.

________. 2001c. Construction of hazard perception and activism on the Internet: Amplifying trivial risks and obfuscating serious ones. Natural Hazards Research Working Paper 106.

Savage, Donald. 2000. NASA outlines Mars exploration program for next two decades. NASA press release 00-171 (26 October). Available at: http://nssdc.gsfc.nasa.gov/planetary/text/mars_pr_20001026.txt.

Wood, Troy D. 2002. Is a Mars Sample Return Mission too Risky? A Public Hearing Case Study. Available at: http://ublib.buffalo.edu/libraries/projects/cases/mars/mars.html.


document maintained by author
© Christine M. Rodrigue, Ph.D., 2002
first placed on the web: 07/15/02
last revised: 07/15/02