The MARSHKOD Egyptian Drill Project

Abstract Twenty years ago, the arm on the Viking Mars Lander was able to obtain samples from depths up to 10 cm. Today, a drill with the capability of boring at least an order of magnitude deeper (more than one metre) would be essential to further research and investigation. During the Fourth UN/ESA Workshop on Basic Space Science held in Cairo July 1994, the possible participation of Egypt in future Mars missions was discussed. One concept suggested was that Egypt could participate in these missions through involvement in the design, building and testing of a drill for obtaining sub-surface samples.

Sommaire. Il y a vingt ans, le bras de Viking Mars Lander a été capable d'obtenir des échantillons à des profondeurs jusqu'à 10 cm. Aujourd'hui, une foreuse pouvant aller au moins à un ordre de magnitude plus profond (plus d'un mètre) serait essentielle à d'autres recherches et investigations. Pendant le Quatrième Groupe de Travail UN/ESA sur les Sciences Spatiales qui s'est tenu au Caire en Juillet 1994, une possible participation de l'Egypte dans de futures Missions vers Mars fut discutée. Une suggestion fut que l'Egypte participe à ces missions en s'impliquant dans la conception, la réalisation et le test d'une foreuse pour obtenir des échantillons en profondeur.

1. Introduction

An exobiology strategy for Mars exploration has been developed to determine the planet's pre-biotic/biotic history. The search for evidence of life operationally becomes the search for liquid water, past or present. The optimal approach is a series of missions with increasing resolution that progress from global reconnaissance, to high-resolution imaging of minerals characteristic of aqueous activity and those lithologies capable of preserving biosignatures. Identification of a promising lithology would lead to analysis for the presence of organic matter, which, if positive, would be followed by progressively detailed elemental, molecular and isotopic analyses. The search for biosignatures involves a search in both time and space for the pre-biotic/biotic history of Mars.^[1]

During the summer of 1976 the two Viking spacecraft arrived at Mars. Their primary objective was to determine if there was life on Mars. The results of the three life-detection experiments aboard the two landers, while not definitive, did not show the presence of extant life. In addition, the experiments did not find any organic matter in the Martian regolith at either landing site. Although Viking found no life, it provided data to help explain why no extant life was found at the Martian surface. The surface of Mars is an oxidising, desiccated environment devoid of liquid water. However, data from the chemical analyses of the regolith conducted during the Viking mission as well as recent analyses of SNC meteorites suggest that all of the chemical elements necessary for life to arise occur on Mars. Further, Mars and earth accreted from the same interplanetary material, suggesting that the early chemical and physical environment of the two planets may have been similar. If this is true then the prospects for the evolution of life on Mars rest on the degree and the duration of similarity between earth and Mars. Data gathered to date suggests that if liquid water existed on the surface of Mars for sufficient time the probability for life to have arisen is high.^[3]

The Viking landers and orbiters were based mainly upon technologies of the late 1960's, albeit with many advanced developments created specifically for the missions. This was the case not only for the engineering sub-systems, but also for much of the science instrumentation. The Mars Global Surveyor Orbiter mission has science based mainly upon 1980's technologies, because it is derived from the Mars Observer mission instrument complement. Beginning with the Mars Pathfinder Lander, however, 1990's technologies are available. As counterbalance, the budgets for science are now significantly less than at the time of Viking. Borrowing from related commercial, military, and/or earth-orbiting space technologies, a new generation of instruments is being developed. As numerous examples and comparisons testify, through innovative and often bold approaches, the near-term and future instrumentation provides a significantly greater scientific return and an affordable, systematic, and long-term exploration of Mars.^[4]

Among missions planned for the near future is the Russian MARSHKOD mission, in which Egypt will participate through the design, building and testing of a drill for obtaining sub-surface samples.

2. Egyptian expertise in drill development

3. Exobiology Science Objectives

3.1. Search for carbonates and nitrates

Important compounds to be sought on Mars are carbonates and nitrates. Both are expected to be deposited from liquid water and their discovery would confirm that Mars did have standing bodies of water at some time in its past. The presence of carbonates is suggested by models of the early thick atmosphere. Furthermore, determining the presence and abundance of nitrates (a major reservoir of nitrogen) would be key to understanding the volatile abundance and outgassing history of Mars.

3.2. Organics

The Viking results indicated that aeolian dust on Mars is devoid of organic material, apparently due to the action of oxidants produced in the atmosphere and deposited on the surface. Models suggest, however, that there may be organics in deeper layers. Despite the uncertainty, the search for organics remains a key objective for exobiology exploration. Other than the surface oxidants, organics should be well preserved on Mars: the cold, dry climate should be a preservative; tectonics, which on earth result in the heating and metamorphism of sedimentary material, is absent on Mars, and the lack of water should also help isolate and preserve organics buried at depth. Preliminary measurements would focus on the detection of organics to be followed by more complex analysis - isotopic studies comparing organic and inorganic carbon as well as isotopic ratios of the organics.

3.3. Water

Exobiology shares with geology and climate studies the need to understand the distribution and duration of bodies of liquid water through Mars's history. The primary reason Mars holds such interest for exobiology is the extensive geomorphological evidence for liquid water on its surface in the past. This is the only firm evidence we now have for liquid water outside the earth's biosphere. Water, in the liquid state, is the most critical environmental requirement for life as we know it. Therefore the search for past and present life on Mars has naturally focussed on searching for liquid water. The exobiology perspective deals with liquid water as providing a habitat for life and as providing sedimentary and depositional environments that preserve evidence of former life. Studies of water on Mars primarily influence the exobiology mission strategy in terms of site selection.

3.4. Subsurface samples

The Viking landers were able to obtain samples only from depths up to 10 cm. At this depth, only windblown material was collected. The elemental composition of this windblown material was similar at the two Viking sites. It is probable, therefore, that this material represents a globally uniform mantle. To sample materials characteristic of a particular site of interest, for example a paleolake bed site, it will be necessary to get below this dust mantle. The thickness of the dust mantle is unknown but is estimated in places to be less than one metre. In addition, weathering rates on Mars are quite low (one metre per Gyr).

The Viking lander searched for organics in the surface materials. No organics at the level of sensitivity of the instruments (ppb) were detected. This result, coupled with the release of CO₂ from organics seen in the Viking Labelled Release Experiment, and the release of CO₂ when the soil was humidified, have led to the suggestion of the existence of one or more strong oxidants in the Martian soil. The arm is a hollow shaft and the sample runs down this shaft to the analysis instrument.

The analysis instrument consists of an oven in which the sample is heated to temperatures as high as 1000°C. Gases evolved during the heating are analysed for H₂O, CO₂, CH₄, and NO/NO₂. The temperature (and enthalpy of decomposition, if the unit is a differential calorimeter) at which gases are released is indicative of the decomposing material.

4. Statement and preliminary design^[10,11,12]

If the Mars drill does not have to obtain deep cores, as did the ALSD, its mechanism could be of smaller scale. This is a critical point - the mass of an impact-drilling machine, including the drill bit, is closely related to its capacity, particularly hole depth. For example, if the Mars drill needs to drill only 0.5 metre deep, obtain only a few grams of material for analysis, and a degree of mixing between strata is permitted, then an auger bit, would probably be a good choice. The drill bit would be 10 mm diameter by 0.6 m long and have a mass of about 0.25 kg. The proposed total mass for power-head, bit, and control electronics, is 2.0 kg. For reference, the ALSD power head had a mass of 4.04 kg and its drill bit 1.9 kg.

The bit must be driven in a straight line or it will bind and energy will be wasted. To do so will require an articulated arm system. Otherwise, the drill must be mounted on a slide rail with its own feed motor/mechanism. This would cause an additional mass penalty.

A rock dust sample will be collected with an articulated scoop that is controlled separately from the drill. That way, if the bit gets stuck or the drill fails, a surface sampling system will still be available. To minimise mixing of dust from different depths, the drilling procedure will be as follows:

1. Activate the drill and drill to the first depth at which a sample is desired.
2. Turn off the drill but do not withdraw it.
3. Bring the scoop into contact with the top of the dust pile.
4. Activate the drill and drill a few centimetres. Much of the dust augered up from the hole will then be deposited in the collection scoop.
5. Turn off the drill and move the dust sample to the analysis chamber.
6. Continue drilling and taking samples from greater depths in the hole if desired.

5. Development of the Egyptian Drill

In the protocol Egypt agreed to perform a conceptual design study of a drill to work on the martian surface. The Egyptian study was performed in conjunction with a study of the Rover in Russia and included a proposed implementation plan for developing the drill, a schedule, and specification for a prototype unit to be tested later. The Egyptian team finished the design of the Mars Drill in September 1997 and construction of a prototype commenced in 1998. The very arid regions of the Western Desert of Egypt have been identified as sites for testing of instruments destined for Mars. In the meantime, work on the Mars Drill continues. Progress will be reported in future issues of African Skies/Cieux Africains.

References

1. Meyer, M.A. and Kerridge, J.F.,`An Exobiology Strategy for Mars Exploration,'COSPAR 96, Symposium F 3.5, Birmingham, U.K., 14-21 July 1996.
2. Jakosky, B.M.,`Seasonal cycles, climate and climate change on Mars,'COSPAR 96, Symposium F 3.5, Birmingham, U.K., 14-21 July 1996.
3. Mancinelli, R.L.,`Prospects for the Evolution of Life on Mars: Viking 20 Years Later,' COSPAR 96, Symposium F 3.5, Birmingham, U.K., 14-21 July 1996.
4. Clark, B.C.,`Overview of the Techniques of Science on Mars - The Past, Present and Future,'COSPAR 96, Symposium F 3.5, Birmingham, U.K., 14-21 July 1996.
5. Galeev, A.A., Moroz, V.I., Zakharov, A.V., Linkin, V.M., Surkov, Yu.A. and Kremnev, R.S., `Mars '96 Mission,' COSPAR 96, Symposium F 3.5,, Birmingham, U.K., 14-21 July 1996.
6. Holden, C., `A quest for ancient Egyptian air,' Science, 236, p. 1419, (1987)
7. Yoshimura, S., Nakagawa, T., Tonouichi, S. and Seki, K., Studies in Egyptian Culture 6, Tokyo, Weseda University, (1987).
8. El-Baz, F., Mores, B., and Petrore, C.E.,`Remote Sensing at an Archaeological Site in Egypt,' American Scientist, Volume 77, pp. 61-66, (1989).
9. El-Baz, F.,`MARSHKOD Drill : Exobiology Science objectives and Design Consideration,' Private Communications (1995).
10. Mores, B., `MARSHKOD Drill : Statement and preliminary design,' private communications (1995).
11. Brodsky, P.N., Gromov, V.V. and Kemurdjian, A.L.,`Unit for taking and preparing soil sample,' International Conference on Mobile Planetary Robots and Rover Round up, Santa Monica, California, USA, 29 January - 1 February 1997.
12. Gorevan, G., Myrick, T., Rafeek, S. and M.A. Mosalam Shaltout, `Rover Mounted Subsurface: Sample Acquisition systems,' International Conference on Mobile Planetary Robots and Rover Round up, Santa Monica, California, USA, 29 January - 1 February 1997. Will be published in Space Technology.