International science turns the spotlight on Mars
Dr Lutz Richter
German scientists make up 20 percent of the American science team for Mars Two scientific instruments on board the US Mars robot ‘Spirit’
Interview with scientist Dr Lutz Richter from the German Aerospace Center (DLR), member of the science team for the US Mars Exploration Rover (MER) mission.
Question: You are a member of the science team for the US Mars Exploration Rover mission (MER). What is this mission all about and what exactly do you do?
Lutz Richter: The aim of the American Mars mission is to land two powerful rovers, each with a mass of about 180 kilograms, on the surface of Mars in different regions showing signs of different effects caused by flowing water at some point in the past. Using a large set of instruments, the rovers will travel over a distance of no more than a few kilometres, analysing the geology and mineralogy of surface materials and rocks in order to investigate the exact nature of the interaction between the terrain and water. This will allow us to draw conclusions about various processes which are also assumed to be linked to water in other areas of the planet. Each day, the science team and the technical team in the Jet Propulsion Laboratory (JPL) in Pasadena interactively control the movements of the vehicles and the stationary measurements and observations they carry out, depending on the observations and data obtained. Both vehicles are expected to carry out their task for three to four months, until April or May 2004.
My job is to study the stability and possible stratification of the upper Martian soil over the distance covered by the Rovers. I do this by analysing the telemetry of the propulsion system and observing the tracks left by the vehicles through camera images, but also through the interpretation of microscope images. While a vehicle is stationary it is also possible to take soil samples, to expose and observe material up to ten centimetres down.
Question: How did you become involved with this team?
Lutz Richter: The scientists who take part in a space mission are basically selected through a tender process, and it was the same with the Mars Exploration Rover mission (MER). The MER mission in 2000 had a team of around 15 scientists under the guidance of Steven Squyres from Cornell University, but in 2001 the American space agency NASA decided to enlarge the science team to include people who wouldn’t be controlling any of the measuring instruments but who could provide other scientific contributions. I took part in the tender process by proposing to study the physical properties of the soil material traversed by the Rovers, and I was selected in May 2002 together with about 28 other people. Even though we don’t operate any of the instruments, we are fully-fledged members of the mission team.
Question: Are you the only team member hailing from Germany?
Lutz Richter: No, because two of the measuring instruments on the Rovers are actually from Germany (the APX and Moessbauer spectrometers), and that alone means that several German scientists are involved. The people in charge of the APX are Rudolf Rieder, Heinrich Wänke and Ralf Gellert (Max Planck Institute for Chemistry in Mainz), and the team responsible for the Moessbauer spectrometer are Goestar Klingelhöfer, Bodo Bernhard and Paolo de Souza (University of Mainz). Then, through the tender process I mentioned before, they were joined by Johannes Brückner (Max Planck Institute for Chemistry in Mainz, to assist with the APX), Stubbe Hviid (Max Planck Institute for Solar System Research) and myself. There is no one involved from DLR apart from myself.
Question: Are there any other Europeans in the team? How big is the team?
Lutz Richter: The science team consists of about 50 people altogether, and as well as the Germans there are several scientists from Denmark – who developed the experiment for the magnetic properties of Martian dust – and a French scientist who assists with the APX and Moessbauer spectrometers. All the remaining scientists are from the US.
Question: There have been four missions to Mars over the past few months and some are still underway. Why wasn’t there better coordination on an international level? Wouldn’t it have saved money if the scientists had cooperated more closely?
Lutz Richter: People often forget that Martian exploration as a whole is based on international cooperation. There are committees which coordinate mission objectives years in advance between all the different space agencies, to make sure no efforts are duplicated. The fact that so many missions were launched in 2003 is because it was the best window for launching. If you look at each mission individually, you’ll see that the aims of each one complement each other very well and nothing is duplicated
Question: What are the objectives of the American missions and what are the objectives of the European mission Mars Express?
Lutz Richter: The American Mars landing missions are concerned with what we call ‘field geology’, to help us understand the development of surface materials over time in their regions, particularly with regard to the role of water. For some years, NASA has also been operating two highly successful orbiter probes around Mars (Mars Global Surveyor and Mars Odyssey), which have been measuring the morphology and topography of the surface, the distribution of chemical elements and minerals and weather events in the atmosphere.
The European mission Mars Express contains an orbiter that accounts for about 80% of the cost of the mission, and the Beagle 2 lander, which was sadly lost. Mars Express represents a comprehensive approach, since it examines several questions about Mars simultaneously. Not only will the surface of Mars be three-dimensionally mapped for the first time, to help us interpret geological structures more reliably, but the mission will also search for water-relevant minerals with a previously unthinkable level of sensitivity and perform the most accurate measurements to date of water vapour in the atmosphere. There is also a radar system, which will probe deep underground for ice and a water table: the first time this has been done from orbit by a Mars mission. Beagle 2 was intended to take revolutionary measurements on samples taken from up to two metres deep, using a bore system called PLUTO developed by DLR, in the search for organic molecules. It’s with samples of this type that we have the greatest chance of finding biologically created molecules which may stem from possible earlier life processes on Mars. Our drill can do what no other scientific instrument on Mars is currently able to do: search directly for carbon compounds and thus for traces of life.
Question: What kind of scientific instruments are there on board the American Mars Rover ‘Spirit’, and what are they for?
Lutz Richter: Each of the two Mars Rovers, Spirit and Opportunity, which are identical in design, is equipped with a Pancam, Mini-TES, APX spectrometer, Moessbauer spectrometer, microscope camera (MI), Rock Abrasion Tool (RAT) and a magnetic experiment. Of these, the APX and Moessbauer spectrometers are from Germany and are the only instruments on board that can identify the chemical and mineralogical composition of rocks and soil material using contact measurements on samples. They are mounted on a gripper arm together with the RAT and MI, from where, controlled from Earth, they analyse objects previously selected from camera images by the science team. The objects are first approached by the vehicle, its movements again controlled from Earth.
Question: It’s amazing that both analytical instruments for the Rovers Spirit and Opportunity should come from Germany. How did this come about?
Lutz Richter: There is a tradition in Germany for manufacturing high-performance, miniaturised measuring instruments for planetary landing missions, and in 1997 the forerunner of the current APX spectrometer was the only measuring instrument on the American Mars Pathfinder mission to provide new scientific findings.
Question: You have developed a ‘mole’ drill for use on Mars. What is special about this drill?
Lutz Richter: This drill, called PLUTO (Planetary Underground Tool), is the only system that with a weight of less than 900 grams can take samples of planetary dust and sand from depths of up to two metres. Instead of being a rotating drill, the machine is based on a 280mm-long pencil-like cylinder on a cable that moves gradually into the ground by means of displacement (using an internal impact mechanism). PLUTO was developed at DLR’s Institute of Space Simulation in partnership with the VNIITransmash Institute in St. Petersburg, Russia.
Question: The drill was on the European lander Beagle 2, which has not made contact since its landing on 25 December 2003. Are you still holding out any hope of making contact?
Lutz Richter: No, we haven’t really been holding out any hope for some time. We might still entertain the hypothesis that the landing was successful but an electronic or software problem, for example, has prevented radio contact. However, we have to assume that Beagle 2 did not survive the landing, possibly because it approached the ground too fast due to the Martian atmosphere, which at the end of December was very hot because of dust storms and therefore less dense than expected.
Question: How much did the Mars drill cost? Will you have to write it off completely?
Lutz Richter: The development of the entirely new PLUTO drill, including the design of several similar systems, cost around €1.9 million. Of this, we have only lost around €200 000, which was the cost of building the flight unit on Beagle 2. The development costs, on the other hand, haven’t been wasted because we are now in a position to deploy PLUTO in future planetary missions at comparatively low cost.
Question: In what other missions could the Mars drill be called upon?
Lutz Richter: Firstly there’s the American Mars mission scheduled for 2009, Mars Science Laboratory (MSL), and then there’s the Mars mission ExoMars, part of the ESA’s planned AURORA programme (2009 or 2011). Additionally, within the Beagle 2 consortium people are already seriously considering revising the design of the Beagle 2 lander and achieving the unique mission objectives of Beagle 2 using a new flight window, possibly as early as 2007.
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