The 1998 Selwyn Lecture was given by Dr Matthew Golombek, a research scientist at JPL (Jet Propulsion Laboratories), specialising in structural geology and tectonics of Earth and other planets and their satellites, with recent emphasis on Mars. He is the Project Scientist of the Mars Pathfinder Project, which means he is the chief scientist of the mission. This position involves wide-ranging responsibilities: overseeing the scientific content of the mission, communicating the mission progress to both the scientific community and the general public, and assisting in decisions regarding the management and budget of the project.

Dr Matthew Golombek outlined the results of the Mars Pathfinder Project in video, slides (some in 3D), and described the deployment of the Martian Rover, Sojourner, including description of the Martian landscape and analysis of the Martian rocks and atmosphere.
The Mars Pathfinder Project is a 'discovery class project', designed to set the stage for future explorations and to be 'Faster, Cheaper and Better'. It was faster in that it took only three and a half years to complete the vehicle and successfully launch it. The mission was cheaper—at less than US$250 million, it cost less than some big-budget Hollywood movies and much less than the previous Mars mission, which cost US$3.5 billion. Better does not really refer to records set, such as the number of internet hits on the project web site on the landing day (47 million), or even to the new Martian land-speed record set by the Martian Rover (90 m in 100 days)! It refers to the knowledge gained and to the true value of the space programme—bringing the world together.
 
1998 SELWYN LECTURE: The Martian Landscape
Dr. Matthew Golombek, Research Scientist, Jet Propulsion Laboratories
The Pathfinder left Earth in December 1996 and landed on Mars on July 4, 1997. Using video and slides, Dr Golembek showed how the landing site was selected and modelled the landing sequence—the lander inflating airbags and bouncing along the surface of Mars (the first bounce back up to 40 m high), before coming to rest and deploying the scientific equipment, including the Martian Rover, the Sojourner—a little 'one foot high mechanical geologist'.
The area of the landing was in Ares Valles, a shallow valley near a series of low hills. The surface was covered with dust, with many rocks up to boulder size scattered about. Slides taken from orbit show numerous channels and even what appear to be lake basins. Ares Valles is part of one such channel system, suggesting water flow at some time between 3.9 and 1.8 billion years ago. The size of the boulders suggests high velocity flow and it is postulated that there were a series of catastrophic floods. The 3D slides, which we observed through those red and blue plastic glasses, showed a ridge and trough topography, with the boulders concentrated along the ridges. The troughs are though to represent late stage drainage of t~e flood waters.
Martian Rocks
The Sojourner trundled around the site of the landing analysing the chemical composition of the rocks and soil with its alpha proton X-ray spectrometer and collecting images of the rock specimens. A number of surprises were in store! Many of the rocks were much higher in silica than expected. Instead of the expected mafic rocks (39–52% SiO2), there were a range of compositions through to andesite, with the rock referred to as Barnacle Bill containing 59% SiO2. Many of the rocks appeared volcanic, with what could be vesicles. There were, however, other types of rocks around, including one containing rounded structures—pebbles or concretions. If these are indeed pebbles, a conglomerate rock on Mars is an important find, indicating repeated cycles of flooding, lithification and erosion.
Past Conditions
Data collected by the Pathfinder Project and earlier missions has raised numerous questions about the past conditions of the Martian surface. These questions centre around the issue of liquid water and the implications this may have for the development of life.
  • Were the channels contemporaneous or interspersed through time?
  • Was there an ocean in Mars' northern hemisphere and how deep was it (perhaps tens to hundreds of meters deep)?
  • Where did the water go? This question has sparked a variety of theories: locked up as ground ice, stored at the poles, or into the atmosphere?
  • Do these indications of liquid water point to warmer and wetter conditions on Mars in the past, or were the floods due to geothermal heating?
  • Did life start on Mars? If so, what happened to it?
The Future
The performance of the landing module exceeded expectations, but eventually ceased to transmit, probably as a result of temperature variations ranging from 260º and 200ºK in the course of a Martian day. This is not the end of the story as more missions to Mars are planned. NASA hopes to send landers every 26 months. A landing at the South Pole is planned, and samples will be taken in the 2005 mission, which will return in 2008. More detail on the Pathfinder mission and future missions to Mars, as well as links to publications resulting from Pathfinder, can be found at http:/ /mpfwww.jpl.nasa.gov7.
Barry Jones gave a vote of thanks to conclude proceedings. The theme of funding arose again, but also the importance of such public lectures—that in these days of 'superspecialisation' it is important that scientists communicate their enthusiasm and knowledge of their science to the public. Raia Wall