- Email: [email protected]
Developing a new controllable lunar dust simulant: BHLD20
Planetary and Space Science 141 (2017) 17–24
Contents lists available at ScienceDirect
Planetary and Space Science journal homepage: www.elsevier.com/locate/pss
Developing a new controllable lunar dust simulant: BHLD20 Hao Sun
a,b,c
, Min Yi
d,⁎
, Zhigang Shen
a,b,⁎⁎
, Xiaojing Zhang
a,b
, Shulin Ma
a,b
MARK
a
School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China Beijing Key Laboratory for Powder Technology Research and Development, Beijing 100191, China Honors College of Beihang University, Beijing 100191, China d Institute of Materials Science, Technische Universität Darmstadt, Darmstadt 64287, Germany b c
A R T I C L E I N F O
A B S T R A C T
Keywords: BHLD20 Lunar dust simulant Lunar atmosphere Moon
Identifying and eliminating the negative effects of lunar dust are of great importance for future lunar exploration. Since the available lunar samples are limited, developing terrestrial lunar dust simulant becomes critical for the study of lunar dust problem. In this work, beyond the three existing lunar dust simulants: JSC1Avf, NU-LHT-1D, and CLDS-i, we developed a new high-fidelity lunar dust simulant named as BHLD20. And we concluded a methodology that soil and dust simulants can be produced by variations in portions of the overall procedure, whereby the properties of the products can be controlled by adjusting the feedstock preparation and heating process. The key ingredients of our innovative preparation route include: (1) plagioclase, used as a major material in preparing all kinds of lunar dust simulants; (2) a muffle furnace, applied to expediently enrich the glass phase in feedstock, with the production of some composite particles; (3) a one-step sand-milling technique, employed for mass pulverization without wasting feedstock; and (4) a particle dispersant, utilized to prevent the agglomeration in lunar dust simulant and retain the real particle size. Research activities in the development of BHLD20 can help solve the lunar dust problem.
1. Introduction Lunar surface is dusty, and flying dirt spreads everywhere, creating a permanent, levitated dust cloud around the moon (Horanyi et al., 2015). Especially near the sunrise, intensive dust storm forms in the lunar electric field (Grün et al., 2011). It is this abundant lunar dust (< 20 µm) that will be troublesome and have many negative effects on future astronaut's lunar explorations. According to the reports of the Apollo missions, the function of thermal-control systems, opticalimaging systems, spacesuits, and some mechanical facilities gradually degraded, due to the covering, adhering and abrasive effects of the ubiquitous dust. Nearly all the lunar dust problems are ascribed to the characteristics of lunar dust itself, especially with its possession of agglutinates and nanophase iron (np-Fe°) (Sen et al., 2011), high maturity (Taylor et al., 2001a), ultrafine particle size (Park et al., 2008), charging and floating properties (Abbas et al., 2010, 2007; Nemecek et al., 2011; Stubbs et al., 2006), adhesion and abrasion abilities (Kobrick et al., 2011; Walton, 2007), potential toxicity (Linnarsson et al., 2012), etc. It is essential to develop solutions for minimizing the influence of lunar dust on future lunar exploration programs. Using the real lunar sample for study is definitely an ideal
⁎
option. However, due to the precious nature of the Apollo lunar samples, it is not feasible to use sufficient quantities for many engineering studies; hence, the production of lunar soil and dust simulants becomes quite important (Liu and Taylor, 2011; Taylor et al., 2016). Thanks to the compatibility in geology between the Earth and its Moon, most lunar substances can be simulated using terrestrial materials. As a renewed interest in lunar exploration emerged at the beginning of this century, and with this a need for lunar soil and dust simulants began to appear (Liu and Taylor, 2011). Currently, three lunar dust simulants have been developed, i.e. JSC-1Avf (Park et al., 2008; Wallace et al., 2009) and NU-LHT-1D (Stoeser et al., 2008, 2010) from the U.S., and CLDS-i (Tang et al., 2017) from China. Detailed studies have shown that with the decreasing of grain size, the contents of Al2O3 and CaO (feldspathic components) increase in most lunar regolith samples, while the contents of FeO, MgO, and TiO2 (mafic components) decrease (Laul and Papike, 1980; Taylor et al., 2001a, 2001b, 2003). However, most previous lunar dust simulants were prepared from their basaltic or feldspathic soil origins. In this work, we will combine feldspathic raw material with a basaltic one, in order to prepare a new lunar dust simulant named as BHLD20. The agglutinate glass makes up
Corresponding author. Corresponding author at: School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China. E-mail addresses: [email protected] (M. Yi), [email protected] (Z. Shen).
⁎⁎
http://dx.doi.org/10.1016/j.pss.2017.04.010 Received 12 September 2016; Received in revised form 7 April 2017; Accepted 9 April 2017 Available online 13 April 2017 0032-0633/ © 2017 Elsevier Ltd. All rights reserved.
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
35–70% of the lunar dust (Taylor et al., 2001a, 2010), playing an important role in affecting lunar dust characteristics (Gustafson et al., 2007). Former endeavors to manufacture agglutinate simulants relied on specialized facilities and were of low yield (Sen et al., 2011; Weinstein and Wilson, 2013; Gustafson et al., 2011; Hung and McNatt, 2012). Present work will propose a convenient method by using a high-temperature muffle furnace and a cold-water basin, through which the abundance of glass phase or the maturity of BHLD20 can be controlled (partial melting). Since lunar dust simulant is a sort of ultrafine powder material, conventional dry milling and sieving methods used in preparing lunar soil simulant are no longer applicable and are of low yield as well (Basu et al., 2001; Graf, 1993; Liu and Taylor, 2011). In this work, we will apply wet sand-milling technique to make the mass production of lunar dust simulant possible. In order to prevent the violent agglomeration that happens in this ultrafine powder, we will first introduce dispersant into the preparation of lunar dust simulant, thus to avoid measuring error of particle size distribution (PSD). In the last part, we will demonstrate the intrinsic features of BHLD20, and making comparisons with lunar dust samples, especially in the aspects of PSD, particle morphology, modal abundance, and chemical composition. With the mission of collecting lunar sample for research, Chang’E-V probe is schemed to launch in the near future, and will land on the far side of the moon. Current studies on developing lunar dust simulant are definitely bound to help handle with that precious sample in an appropriate manner. Besides, high-fidelity lunar dust simulant can be used to emulate lunar cloudy environment, and help study the mechanisms by which lunar materials interact with extravehicular facilities as well as the human body. It is anticipated that the development of the new controllable lunar dust simulant BHLD20 will contribute a lot to the future lunar exploration.
Fig. 1. (a) Particle size distributions (PSD) of lunar dust samples (Park et al., 2008). Median particle size of Apollo 11 lunar dust sample 10084 is ~100 nm, and median particle size of Apollo 17 lunar dust sample 70051 is ~300 nm. (b) Differential PSD of JSC-1Avf: median particle size is 600–700 nm (Park et al., 2008). (c) Particle accumulative quantity percent (integral PSD) of JSC-1Avf, compared with those of the lunar dust samples (Park et al., 2008).
processes, lunar dust simulant JSC-1Avf can be obtained from JSC-1A. Median particle size of JSC-1Avf is 600–700 nm, larger than that of Apollo lunar dust samples (100–300 nm), as shown in Fig. 1 (Park et al., 2008).
2. Existing lunar dust simulants Numerous lunar regolith simulants have been developed so far, among which the JSC, NU-LHT, and CLRS (CAS) are the most complete series because they all have a dust level product, namely the JSC-1Avf, NU-LHT-1D and CLDS-i, respectively. Their brief information is shown in Table 1.
2.2. NU-LHT-1D NU-LHT-1D is developed by NASA Marshall Space Flight Center and United States Geological Survey, mainly for ground-based lunar highland researches (Liu and Taylor, 2011; Schrader et al., 2009). Feedstock of NU-LHT-1D is complex. It is a mixture of norite, anorthosite, and hartzburgite that are mined at Stillwater near Beartooth mountains, as well as some natural ilmenite. Minerals in these rocks include plagioclase, orthopyroxene, clinopyroxene, olivine, chromite, ilmenite, etc. The confected feedstock has made references to the Apollo 16 lunar samples (Stoeser et al., 2010). Because of the total absence of amorphous phase in the feedstock, it is indispensable to prepare the agglutinate analog and pure glass for all the NU-LHT products. Zybek Advanced Products Inc. (ZAP) is responsible for manufacturing the glass phase of NU-LHT-1D (Weinstein and Wilson, 2013). However, npFe° is not present in this product. Ball milled and wet-sieved product NU-LHT-1D has a grain size of < 36 µm (Stoeser et al., 2008), which is slightly larger than lunar dust standard < 20 µm.
2.1. JSC-1Avf JSC-1Avf is the first lunar dust simulant (< 20 µm). It is the finest portion of JSC-1A that has been developed by Orbital Technologies Corporation (ORBITEC) (Liu and Taylor, 2011; Gustafson et al., 2007; McKay et al., 1993). Feedstock for producing JSC-1Avf is mined from a basaltic pyroclastic sheet deposit at San Francisco volcanic field near Flagstaff, which contains volcanic glass, plagioclase, clinopyroxene, orthopyroxene, olivine, magnetite, ilmenite, and apatite. This volcanic tuff resembles some Apollo 14 and Apollo 17 lunar soil samples (Ray et al., 2010; Wallace et al., 2009). ORBITEC uses an impact mill to pulverize the feedstock and produce the lunar soil simulant JSC-1A. Besides, ORBITEC and Plasma Processes Inc. have developed specialized facilities to manufacture the glassy agglutinate analog respectively (Gustafson et al., 2011; Sen et al., 2011). Product analyses manifest that both approaches can provide satisfactory lunar agglutinate simulant with the inclusion of np-Fe°. Through ball milling and wet-sieving
2.3. CLDS-i CLDS-i is another lunar dust simulant that has been developed by Chinese Academy of Sciences and China National Astronomical Observatories (Tang et al., 2017; Zheng et al., 2009). It has a composition similar to JSC-1Avf, and JSC-1A actually. Feedstock of CLDS-i is scoria deposit that is mined from a volcanic field located in the northeastern China. Minerology and chemistry of the basaltic pyroclast are comparable with those of some Apollo 14, 15 soils, making such material an optimal choice in China to produce relevant lunar simulant (Liu et al., 2007). In order to increase the proportion of glass phase in the feedstock, they utilize magnetic separation method to
Table 1 Existing lunar dust simulants. Simulant
JSC-1Avf
NU-LHT-1D
CLDS-i
Reference sample Producer Available year
Apollo 14, 17 ORBITEC 2006
Apollo 16 NASA/USGS 2006
Apollo 14, 15 CAS 2017
18
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Table 2 Chemical composition of CLDS-i (Tang et al., 2017) compared with those of representative Apollo lunar dust samples (Laul and Papike, 1980; Hill et al., 2007). Sample
10084 < 10 µm
14163 < 10 µm
15271 < 10 µm
64501 < 10 µm
70051 < 45 µm
CLDS-i
SiO2 TiO2 Al2O3 Cr2O3 MgO CaO MnO FeO** Na2O K2O Total
41.30 7.30 16.30 0.29 7.20 12.70 0.18 15.10 0.47 0.16 101.00
48.50 1.70 19.0 0.19 8.00 11.30 0.12 9.20 0.71 0.59 99.31
46.00 1.50 19.80 0.30 8.70 12.30 0.13 10.30 0.50 0.23 99.76
45.60 0.45 27.40 0.10 4.30 16.10 0.06 4.40 0.47 0.15 99.03
41.10 4.51 18.60 – 9.00 11.80 0.16 11.90 0.28 0.10 97.45
49.99 1.22 14.09 – 8.16 7.17 0.11 11.53 2.78 1.23 94.17
enrich the inherent volcanic glass to some extent. Coarse glass-rich feedstock then is ground by a planetary ball mill and an ultrasonic crusher. The grinding process is conducted in liquid phase so that a freeze-drying technique is applied to obtain powder form. By means of pulse laser sputtering, grains in CLDS-i are at last coated with some npFe° globules specially (Tang et al., 2017, 2012). Testing results show that the median particle size of CLDS-i is about 500 nm, glass phase in CLDS-i is ~75%, and bulk chemistry is eligible according to Apollo lunar dust samples, as listed in Table 2. Fig. 3. (a) Photos of feedstock of lunar dust simulant BHLD20. (b) Elemental compositions of the scoria and plagioclase, compared with those of bulk 14163 soil sample and its agglutinate component.
3. Experimental details The purpose of this work is to improve the existing routes for the preparation of lunar dust simulant, and develop a new route for the controllable as well as massive production of lunar dust simulant. The outline of developing lunar dust simulant BHLD20 is shown in Fig. 2, whose details will be discussed below.
Fig. 3(b). Both the compositions of scoria and plagioclase are comparable with those of lunar soil sample 14163 and its agglutinate component (Walker and Papike, 1981). With introducing mineral plagioclase that is abundant in lunar dust, theoretically the fidelity of dust simulant gets higher. Moreover, it provides possibility of preparing highland type dust simulant along the same route.
3.1. Preparation of feedstock
3.2. Enhancing the glass phase content
Feedstock of lunar dust simulant BHLD20 is a mixture of basaltic scoria and anorthositic plagioclase, as shown in Fig. 3(a). The scoria (top left of Fig. 3(a)) is mined from a volcanic field in Huinan, China, and its mineralogy and chemistry have been testified close to some Apollo 14 lunar soils (Liu et al., 2007). As mentioned above, most lunar dust samples are more feldspathic than coarser soils. Hence, by introducing feldspathic minerals into basaltic feedstock to improve the precision of lunar dust simulant is a reasonable attempt (Taylor et al., 2001a). All kinds of feldspars are available at Taihang Mountains in Lingshou, China. By blending and melting the anorthite with albite in a proper ratio, anorthositic plagioclase (anorthite > 50%) can be acquired (bottom left of Fig. 3(a)). Though it is a terrestrial version, as the scoria, it has certain similarities to lunar feldspars compared with other minerals. Bulk chemistries of BHLD20 raw materials are shown in
In this work, high-temperature muffle furnace is used to increase the amount of glass phase in BHLD20 with some composite particles. As we know, perfect agglutinates on the moon are highly vesicular with abundant mineral fragments and np-Fe° entrained in impact glasses (Heiken et al., 1991). Given that the lunar agglutinates are created in specific space environment, partial melting is crucial for reproducing this heterogeneous material (Ray et al., 2010; Sen et al., 2011). According to Bowen's reaction series (Bowen, 1922), basic mineral has higher melting point than intermediate or acid one, as is the case in plagioclase. While in the feedstock of BHLD20, there coexists basic minerals (e.g. anorthite, pyroxene), acid minerals (e.g. albite) and ultrabasic minerals (e.g. olivine). Hence both the heating temperature
Fig. 2. Preparation route and major facilities for producing lunar dust simulant BHLD20.
19
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Fig. 4. The XRD and SEM results of representative melted products. (a) Pristine feedstock without heat treatment. And melted products produced by heating at (b) 1200 °C for 20 min, (c) 1200 °C for 30 min, and (d) 1200 °C for 2 h. Red boxes in the SEM images in (c) and (d) indicate a few glass-rich composite particles that are highly irregular and in agglomerate form. (b) has so many glass-rich composite particles that red boxes are not assigned. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
and time should be carefully chosen to control the extent of crystalline phase melting to amorphous glass. In our experiment, feedstock comprised of scoria and plagioclase was milled for uniform mixing before heating. Then the mixture was heated at a temperature from 1000 °C to 1300 °C for 10 min to 120 min. To avoid recrystallization, each molten product was thrown into a water basin as soon as heat treatment was finished. The glass-rich products were dried for further characterization. Based on the XRD patterns, optical and SEM images of all the products, we found that the abundance of amorphous phase or the maturity is indeed controllable by adjusting the heating temperature and time. Representative XRD, optical and SEM results of the melted products are shown in Fig. 4. Melting experiment reveals that not high enough temperature or short heating time leads to low glass phase yield (Fig. 4(a)), yet too high temperature and too long heating time generate nearly all pure glass (Fig. 4(c)(d)). The product obtained at 1200 °C for 20 min (Fig. 4(b)) is believed to be reasonable; because it has a moderate amount of glass phase along with a large number of irregular and heterogeneous suspected “agglutinates”, as the features of real lunar dust (Taylor et al., 2001a, 2001b). However, more careful observation shows that such suspected “agglutinates” are only a sort of glass-rich composite particles, in which vesicular structures are not that abundant as well as the np-Fe° globules are absent. Even so, it is the total glass phase content that contributes a lot to general engineering uses (Liu and Taylor, 2011). The degree of feedstock vitrified by muffle furnace as a function of heating temperature and heating time is summarized in Fig. 5. Through heat treatment, the abundance of glass phase in BHLD20 can be regulated and determined. It should be noted
Fig. 5. Results of producing lunar amorphous analog by muffle furnace. Black and grey dots display different heating conditions in the melting experiment. “feedstock” here means melted products that are devoid of man-made amorphous phase. “partial-melted products” represents melted products that have a moderate amount of glass phase as well as a great number of glass-rich composite particles. “pure glass” represents melted products that have been overheated.
that once the melted product being pulverized, they will split into smaller crystals, pure glasses, and glass-rich composite particles. Among which the latter two, i.e. the amorphous components are dominant. The glass-rich material prepared here is an ideal intermediate product for developing dust simulant BHLD20. 20
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
TEM image in Fig. 6(a). Therefore, the median particle size was significantly increased to ~ 2.3 µm (Fig. 6(b)). Here we tried to use dispersant to make the submicron particles better dispersed. By a few trials with different dispersant candidates, we found that the silane coupling agent A151 (Vinyltriethoxysilane) performed the best. After the slurry of lunar dust simulant with A151 was sonicated and stirred, the particle size approached to its original level (200–300 nm), as shown in Fig. 6(c). Well dispersed slurry was then dried to obtain the dispersive ultrafine powder. Fig. 6(d) gives a typical SEM image of the dried powder in the case of 0.5 wt% A151 and 8 h sonication. We found that after drying, only a few soft agglomerates existed and they could be easily crumbed with fingertips. In order to satisfy the ground-based applications which require a dusty cloud environment, the dried ultrafine powder was subsequently treated with a jet mill to ensure that all the soft agglomerates were fully pulverized. Finally, a rather loose lunar dust simulant, i.e. BHLD20, came into being, as shown in Fig. 7(a).
As for lunar np-Fe°, its forming mechanism is still not quite clear, but it contributes to the optical, magnetic, and toxic properties of lunar regolith (Keller and McKay, 1993, 1997; Pieters et al., 2000; Sasaki et al., 2001; Wallace et al., 2010). While on the earth, lunar simulant with this active metallic iron will be sensitive to the atmosphere and quickly become an oxygen “getter”. Hence it is not easy to reserve the reductive np-Fe° in terrestrial tests. Recently, it has been confirmed that the activities preparing np-Fe° in lunar simulant is costly and laborintensive, with rather limited application prospect (Taylor et al., 2016). Thereby in view of general uses, no single-domain np-Fe° is expressly prepared or introduced into BHLD20. Even so, BHLD20 has certain magnetic properties because of the presence of terrestrial magnetite, which is similar to the case of JSC-1A (Liu and Taylor, 2011).
3.3. Pulverization and particle dispersion In this study, a sand-milling machine (1 L) was employed to straight grind the above intermediate product (1200 °C-20 min partial-melted simulant) down to ultrafine level in deionized water without any sieving process. After the grinding process, a slurry of BHLD20 was acquired. And the solid content of the slurry is about 30–50%. Via a Malvern laser particle sizer, the PSD of the slurry product was measured right after the milling process. Result showed that the median particle size was about 285 nm, which matched well with the size of wet-sieved lunar dust samples. This size distribution was better than that of any previous lunar dust simulant. However, violent agglomerate induced submicron particles to form particle clusters very quickly, as shown the
4. Results and discussion To evaluate the fidelity of a lunar dust simulant, it is necessary to compare it with the lunar dust samples, especially in the aspects of PSD, particle morphology, modal abundance, and bulk chemistry (Liu and Taylor, 2011; Taylor et al., 2016). The similar characterization methods for lunar samples were applied to BHLD20.
Fig. 6. (a) TEM image of dried BHLD20 without dispersion. Red circles indicate agglomerate clusters consisting of numerous smaller grains. (b) Particle agglomeration leading to an enlarged PSD result (from the black curve to the blue). (c) Particle aggregation was mitigated by introducing dispersant A151, and A151 of 0.5 wt% concentration along with 8 h ultrasonication performs the best. (d) SEM image of the dried and well dispersed BHLD20 product. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
21
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Fig. 1(a). It must be emphasized that our PSD measurements were made with a laser technique that does not reproduce that used in the Apollo samples’ PSD measurements (Taylor et al., 2016). In this way, actually the PSD of BHLD20 we acquired is a little finer than that of a wet-sieved product. Fortunately, the PSD can also be expediently adjusted to whatever level through the straight sand-milling method, making the PSD another controllable factor during the development of lunar dust simulant. Although laser technique is a modern method characterizing particle size, wet-sieving is still a suitable technique for reserving the nature of lunar dust. Owing to the long-time “space gardening” on the moon, the particle size level is corresponding to the characteristics of the lunar material (Laul and Papike, 1980). Therefore, future lunar samples are not suggested to be straight comminuted to dust level, but suggested to be sieved carefully in consideration of the diversity among dust, soil, and rock. 4.2. Morphology When it comes to the morphology or shape information of particles in lunar regolith, we always refer to their 2D projection (Liu et al., 2008). Fig. 8 shows SEM images of five representative particles from BHLD20. In all kinds of particles, the glass-rich composite particle is the most irregular one with considerable specific surface area. An appreciable quantity of glass beads reside in BHLD20, which take up a great part especially on the nanoscale. Complexity and aspect ratio are the most significant geometrical algorithms to quantify the morphological feature of lunar grains (Rickman et al., 2012). Their expressions are shown in Fig. 8 and are explained via particle Fig. 8(b), in which a is the half major axis of an equivalent ellipse, b is the half minor axis, C is the perimeter of a particle's 2D projection, and S is the area of the projection. Shape information of BHLD20 is calculated and listed in Table 3. The averages are derived from a SEM image of BHLD20. The aspect ratio of BHLD20 is smaller than lunar dust samples’ average while the complexity is bigger, meaning that particles in BHLD20 are more flat in profile, but not as rough as lunar dust samples. One reason for this is the lack of massive vesicular structures that lunar agglutinates obtained from the micrometeorite bombardments on lunar surface. (Liu et al., 2008).
Fig. 7. (a) Photo of lunar dust simulant BHLD20. (b) PSD of BHLD20 measured by laser particle analyzer. Black line is the differential distribution after coordinate transformation to match the PSD of Apollo lunar dust samples, and pink line is the integral distribution. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
4.1. Particle size distribution (PSD) Laser particle analyzer was used to measure the PSD of both BHLD20 powder and BHLD20 slurry. Differential PSD result of BHLD20 powder is close to the black curve in Fig. 6(c). After a coordinate transformation, final PSD of BHLD20 in accord with Fig. 1 is illustrated by Fig. 7(b). All grains are smaller than 20 µm and the median particle size drops to an unprecedented value: 250–300 nm, quite similar to the size of wet-sieved Apollo dust samples shown in
4.3. Modal abundance Modal abundance refers to the quantities of diverse minerals and glass phase in a geologic sample, in this case, a lunar material (Rickman et al., 2011). According to the feedstock constituents (Liu et al., 2007) and the XRD result of the melted product after heat treatment, modal constituents in BHLD20 include glass-rich composite particles, volcanic
Fig. 8. Representative particles in BHLD20 and the algorithms to quantify their shape information. (a)(b) Glass-rich composite particles that are irregular but devoid of vesicles. (c)(d)(e) Glass beads that are smooth and regular. (b) is chosen to explain the method characterizing the morphology of a single particle.
22
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Given the modal abundance and chemical composition of BHLD20 in Fig. 9, we suggest that a mare dust simulant can be made by introducing more Ti-magnetite/ilmenite and glass components into BHLD20 (Weiblen et al., 1990); however, this also depends upon whether we are referring to high-Ti mare (Apollo 11 and 17) or lowTi mare (Apollo 12 and 15). Whereas the lunar highland dust simulant can be made by introducing more plagioclase. The chemistry of the glass phases can be different from place to place, but it can be adjusted in the feedstock preparation process, before heat treatment. However, each Apollo lunar sample represents only a limited lunar surface. No simulant can represent the whole lunar mare or highland. What we can do is to try our best to approach more close to either the lunar mare samples or the lunar highland ones. It seems that the composition discrepancies in dust samples are not as large as those in soils, probably due to the selective comminution, lateral mixing, and preferential melting of space weathering (Taylor et al., 2010). Therefore, as an “intermediate” between mare and highland dust, BHLD20 is generally close to most lunar dust samples. Moreover, its high-glass abundance makes it a competent simulant for many ground-based geotechnical applications.
Table 3 Morphological result of BHLD20 compared with those of Apollo lunar samples (Liu et al., 2008). Parameter
Aspect ratio
Complexity
BHLD20 Lunar sample
0.58 0.70
1.05 1.15
glass, plagioclase, olivine, pyroxene, and other minor minerals. In this study, content of glass phase in BHLD20 can be controlled from 25% to nearly 100% by adjusting the heating condition. Since the impact glass in real lunar dust ranges from 35% to 70% (Taylor et al., 2001a, 2010), we designate BHLD20 containing 55% glass phase as the standard product, in which glass-rich composite particles is ~35%, volcanic glass is ~20%. The standard product also contains ~25% plagioclase as well as ~20% other minerals. Apollo 16 highland samples contain large (> 70%) plagioclase (~5 wt% FeO), and represent the soil fraction that occurs in > 80% of the Moon. The Mare samples that occur in the remainder < 20% of the Moon's soil have < 40% plagioclase and about 15 wt% FeO. The lunar dust simulant that we have produced refers to the neither good highland nor mare dust, as shown in Fig. 9(a). However, it is similar to JSC-1Avf lunar dust simulant, which was made primarily for its geotechnical properties, not only the chemistry or mineralogy. The importance of our process for making BHLD20 is that the mineralogy can be easily changed in the production process such that we can make the dust product similar to any dust composition on the Moon. (Taylor et al., 2001a, 2010, 2016).
5. Summary In this work, we put forward an improved route for developing lunar dust simulants, whereby we can prepare a new high-fidelity lunar dust simulant named as BHLD20. In order to more realistically approach the properties of real lunar dust, we introduce plagioclase as a major feedstock. The content of the glass phase in BHLD20 can be modified by use of a muffle furnace to simplify and control the heating process. Instead of wet-sieving, a sand-milling technique was applied for one-step pulverization, guaranteeing a stable chemistry and a high yield of product. The agglomeration of lunar dust simulant was eliminated by introducing an appropriate dispersant. In this way, the finer-grain size of the simulant was realized. However, it must be pointed out that our PSD measurements were made with a laser technique that does not reproduce that used in Apollo samples’ PSD measurements. By diverse characterization methods, nearly all the intrinsic properties of BHLD20 were proved to be close to some of the Apollo lunar dust samples. By variations in the step-wise procedure of producing lunar dust/ soil simulants – i.e., feedstock preparation and heat treatment processes, it is possible to modify the intrinsic properties of the products. Present work proposes an integrated route for preparing lunar dust simulant of different types. It is hopeful that the type of BHLD20 can be controlled from lunar mare to the highland, and from immature to mature. BHLD20 is attractive for a range of ground-based engineering studies related to solving lunar dust problem. And as a precursor prior
4.4. Chemical composition A variety of testing techniques have been applied to the characterization of the bulk chemistry of lunar materials, and X-ray fluorescence spectrometer (XRF) analysis is one of them (Hill et al., 2007). Major rock-forming oxides in BHLD20 tested by XRF are presented in Table 4. From chemical prospective, lunar dust simulant BHLD20 approaches to some Apollo 14 dust samples, whose chemistry lie halfway between lunar feldspathic highland and basaltic mare, but closer to the latter except mafic elements, see details in Fig. 9(b). Total iron oxides in BHLD20 is about 7.93 wt%, which again demonstrates that this BHLD20 product is neither a mare simulant, nor a highland one (Taylor et al., 2001a, 2010). These iron oxides in BHLD20 include Fe2O3 which will not be found on the moon (Lucey et al., 1995). Because of the intrinsic difference in geology between earth material and lunar material, the abundances of SiO2, Na2O, K2O in BHLD20 is slightly higher than those of lunar dust samples. TiO2 in BHLD20 is rare so that it is temporarily a sort of low-Ti lunar dust simulant with an intermediate composition in the current study.
Fig. 9. (a) Modal abundance of BHLD20. (b) Chemical composition of BHLD20. Both manifest that BHLD20 simulant is consistent with most Apollo lunar dust samples (< 10 µm) (Taylor et al., 2001a, 2010).
23
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Table 4 Chemical composition of BHLD20. BHLD20
SiO2
TiO2
Al2O3
Cr2O3
MgO
CaO
MnO
FeO**
Na2O
K2O
Total
Wt%
50.17
1.18
17.21
0.31
3.34
9.41
0.12
7.93
5.59
1.67
96.93
McKay D.S., Carter J.L., Boles W.W., Allen C.C., Allton J.H., 1993. In: Proceedings of the 24th Lunar and Planetary Science Conference, pp. 963–964. Nemecek, Z., Pavlu, J., Safrankova, J., Beranek, M., Richterova, I., Vaverka, J., Mann, I., 2011. Lunar dust grain charging by electron impact: dependence of the surface potential on the grain size. Astrophys. J. 738, 14–20. Park, J., Liu, Y., Kihm, K.D., Taylor, L.A., 2008. Characterization of lunar dust for toxicological studies. I: particle size distribution. J. Aerosp. Eng. 21, 266–271. Pieters, C.M., Taylor, L.A., Noble, S.K., Keller, L.P., Hapke, B., Morris, R.V., Allen, C.C., McKay, D.S., Wentworth, S., 2000. Space weathering on airless bodies: resolving a mystery with lunar samples. Meteorit. Planet. Sci. 35, 1101–1107. Ray, C.S., Reis, S.T., Sen, S., O’Dell, J.S., 2010. JSC-1A lunar soil simulant: characterization, glass formation, and selected glass properties. J. Non-Cryst. Solids 356, 2369–2374. Rickman, D., Immer, C., Metzger, P., Dixon, E., Pendleton, M., Edmunson, J., 2012. Particle shape in simulants of the Lunar regolith. J. Sediment. Res. 82, 823–832. Rickman D.L., Stoeser D.B., Benzel W.M., Schrader C.M., Edmunson J.E., 2011. Notes on lithology, mineralogy, and production for lunar simulants. In: National Aeronautics and Space Administration. NASA/TM—2011–216454. Sasaki, S., Nakamura, K., Hamabe, Y., Kurahashi, E., Hiroi, T., 2001. Production of iron nanoparticles by laser irradiation in a simulation of lunar-like space weathering. Nature 410, 555–557. Schrader C.M., Rickman D.L., Mclemore C.A., Fikes J.C., Stoeser D.B., Wentworth S.J., McKay D.S., 2009. Lunar regolith characterization for simulant design and evaluation using figure of merit algorithms. In: Proceedings of the 47th AIAA Aerospace Sciences Meeting. AIAA 2009–2755. Sen, S., Butts, D., Ray, C.S., Thompson, G.B., Morris, R.A., O’Dell, J.S., 2011. Production of high fidelity lunar agglutinate simulant. Adv. Space Res. 47, 1912–1921. Stoeser D., Wilson S., Weinstein M., Rickman D., Lowers H., Meeker G., Schrader C., McLemore C., Fikes J., 2008. The LHT (Lunar Highlands Type) regolith simulant series. In: Proceedings of The Geological Society of America (GSA) 2008 Joint Annual Meeting. Stoeser D., Wilson S., Rickman D., 2010. Design and specifications for the highland regolith prototype simulants NU-LHT-1M and -2M. National Aeronautics and Space Administration, NASA/TM—2010–216438. Stubbs, T.J., Vondrak, R.R., Farrell, W.M., 2006. A dynamic fountain model for lunar dust. Adv. Space Res. 37, 59–66. Tang, H., Wang, S., Li, X., 2012. Simulation of nanophase iron production in lunar space weathering. Planet. Space Sci. 60, 322–327. Tang, H., Li, X., Zhang, S., Wang, S., Liu, J., Li, S., Li, Y., Wu, Y., 2017. A lunar dust simulant: clds-i. Adv. Space Res. 59, 1156–1160. Taylor, L.A., Pieters, C.M., Keller, L.P., Morris, R.V., McKay, D.S., 2001a. Lunar Mare Soils: space weathering and the major effects of surface-correlated nanophase Fe. J. Geophys. Res. 106, 27985–27999. Taylor, L.A., Pieters, C.M., Keller, L.P., Morris, R.V., McKay, D.S., Patchen, A., Wentworth, S., 2001b. The effects of space weathering on Apollo 17 mare soils: petrographic and chemical characterization. Meteorit. Planet. Sci. 36, 285–299. Taylor L.A., Pieters C.M., Patchen A., Taylor D.H., Morris R.V., Keller L.P., McKay D.S., 2003. Mineralogical Characterization of Lunar Highland Soils. In: Proceedings of the 34th Lunar and Planetary Science Conference. Abstract no. 1774. Taylor, L.A., Pieters, C.M., Patchen, A., Taylor, D.S., Morris, R.V., Keller, L.P., McKay, D.S., 2010. Mineralogical and chemical characterization of lunar highland soils: insights into the space weathering of soils on airless bodies. J. Geophys. Res. 115, 481–492. Taylor, L.A., Pieters, C.M., Britt, D., 2016. Evaluations of lunar regolith simulants. Planet. Space Sci. 126, 1–7. Walker R.J., Papike J.J., 1981. The relationship of the lunar regolith less than 10 μm fraction and agglutinates. Part II: Chemical composition of agglutinate glass as a test of the fusion of the finest fraction (F3) model. In: Proceedings of the 12th Lunar and Planetary Science Conference, pp. 421–432. Wallace, W.T., Taylor, L.A., Liu, Y., Cooper, B.L., McKay, D.S., Chen, B., Jeevarajan, A.S., 2009. Lunar dust and lunar simulant activation and monitoring. Meteorit. Planet. Sci. 44, 961–970. Wallace, W.T., Phillips, C.J., Jeevarajan, A.S., Chen, B., Taylor, L.A., 2010. Nanophase iron-enhanced chemical reactivity of ground lunar soil. Earth Planet. Sci. Lett. 295, 571–577. Walton O.R., 2007. Adhesion of lunar dust. National Aeronautics and Space Administration, NASA/CR—2007–214685. Weiblen P., Murawa M., Reid K., 1990. Preparation of Simulants for Lunar Surface Materials. In: Proceedings of the American Society of Civil Engineers in Space II, pp. 98–106. Weinstein M., Wilson S.A., 2013. Apparatus and Method for Producing a Lunar Agglutinate Simulant. US patent, US008610024. Zheng, Y., Wang, S., Ouyang, Z., Zou, Y., Liu, J., Li, C., Li, X., Feng, J., 2009. CAS-1 lunar soil simulant. Adv. Space Res. 43, 448–454.
to Chang’E-V lunar sample, the practical research activities on BHLD20 can make a significant contribution to future lunar dust sample management, especially in the pulverization and characterization aspects. Acknowledgements The authors would like to thank Prof. Larry Taylor (Tennessee) and the anonymous reviewers for their constructive suggestions and language polish of the manuscript. We gratefully acknowledge the China Academy of Space Technology and the China National Astronomical Observatories for their constructive suggestions. We thank Dongguan Longly Machinery Limited Company, which facilitated part of the research. Funding for the research presented in this paper was provided by Beijing Natural Science Foundation (2132025), and Specialized Research Fund for the Doctoral Program of Higher Education (20131102110016). References Abbas, M.M., Tankosic, D., Craven, P.D., Spann, J.F., LeClair, A., West, E.A., 2007. Lunar dust charging by photoelectric emissions. Planet. Space Sci. 55, 953–965. Abbas, M.M., Tankosic, D., Craven, P.D., LeClair, A.C., Spann, J.F., 2010. Lunar dust grain charging by electron impact: complex role of secondary electron emissions in space environments. Astrophys. J. 718, 795–809. Basu, A., Wentworth, S.J., McKay, D.S., 2001. Submillimeter grain-size distribution of Apollo 11 soil 10084. Meteorit. Planet. Sci. 36, 177–181. Bowen, N.L., 1922. The reaction principle in petrogenesis. J. Geol. 30, 177–198. Graf, J.C., 1993. Lunar Soils Grain Size Catalog. NASA Reference Publication 1265, Houston, Texas, USA (466 pp). Grün, E., Horanyi, M., Sternovsky, Z., 2011. The lunar dust environment. Planet. Space Sci. 59, 1672–1680. Gustafson R.J., White B.C., Gustafson M.A., Fournelle J., 2007. Development of a lunar agglutinate simulant. In: Proceedings, Space Resources Roundtable VIII: Program and Abstracts (LPI Contribution No. 1332), pp. 25–26. Gustafson R.J., Gustafson M.A., White B.C., 2011. Process to Create Simulated Lunar Agglutinate Particles. US patent, US8066796. Heiken, G.H., Vaniman, D.T., French, B.M., 1991. Lunar Sourcebook: A User's Guide to the Moon. Cambridge University Press, Cambridge, pp. 296–302. Hill, E., Mellin, M.J., Deane, B., Liu, Y., Taylor, L.A., 2007. Apollo sample 70051 and high- and low-Ti lunar soil simulants MLS-1A and JSC-1A: implications for future lunar exploration. J. Geophys. Res. 112, 273–300. Horanyi, M., Szalay, J.R., Kempf, S., Schmidt, J., Grun, E., Srama, R., Sternovsky, Z., 2015. A permanent, asymmetric dust cloud around the Moon. Nature 522, 324–326. Hung, C., McNatt J., 2012. Lunar Dust Simulant Containing Nanophase Iron and Method for Making the Same. US patent, US008283172. Keller, L.P., McKay, D.S., 1993. Discovery of vapor deposits in the lunar regolith. Science 261 (5126), 1305–1307. Keller, L.P., McKay, D.S., 1997. The nature and origin of rims on lunar soil grains. Geochim. Cosmochim. Acta 61 (11), 2331–2341. Kobrick R.L., Klaus D.M., Street K.W., 2011. Defining an abrasion index for lunar surface systems as a function of dust interaction modes and variable concentration zones. National Aeronautics and Space Administration. NASA/TM—2010–216792. Laul J.C., Papike J.J., 1980. The lunar regolith: Comparative chemistry of the Apollo sites. In: Proceedings of the 11th Lunar and Planetary Science Conference, pp. 1307–1340. Linnarsson, D., Carpenter, J., Fubini, B., Gerde, P., Karlsson, L.L., Loftus, D.J., Prisk, G.K., Staufer, U., Tranfield, E.M., van Westrenen, W., 2012. Toxicity of lunar dust. Planet. Space Sci. 74, 57–71. Liu, C., Wang, S., Feng, J., Li, X., Fu, S., Ouyang, Z., Zheng, Y., 2007. The geochemistry evidence for selecting the suitable raw material in China to simulate the low titanium lunar soil from lunar-sea basalt. J. Mineral. Petrol. 27, 28–33. Liu, Y., Taylor, L.A., 2011. Characterization of lunar dust and a synopsis of available lunar simulants. Planet. Space Sci. 59, 1769–1783. Liu, Y., Park, J., Schnare, D., Hill, E., Taylor, L.A., 2008. Characterization of lunar dust for toxicological studies. II: texture and shape characteristics. J. Aerosp. Eng. 21, 272–279. Lucey, P.G., Taylor, G.J., Malaret, E., 1995. Abundance and distribution of iron on the moon. Science 268, 1150–1153.
24
Contents lists available at ScienceDirect
Planetary and Space Science journal homepage: www.elsevier.com/locate/pss
Developing a new controllable lunar dust simulant: BHLD20 Hao Sun
a,b,c
, Min Yi
d,⁎
, Zhigang Shen
a,b,⁎⁎
, Xiaojing Zhang
a,b
, Shulin Ma
a,b
MARK
a
School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China Beijing Key Laboratory for Powder Technology Research and Development, Beijing 100191, China Honors College of Beihang University, Beijing 100191, China d Institute of Materials Science, Technische Universität Darmstadt, Darmstadt 64287, Germany b c
A R T I C L E I N F O
A B S T R A C T
Keywords: BHLD20 Lunar dust simulant Lunar atmosphere Moon
Identifying and eliminating the negative effects of lunar dust are of great importance for future lunar exploration. Since the available lunar samples are limited, developing terrestrial lunar dust simulant becomes critical for the study of lunar dust problem. In this work, beyond the three existing lunar dust simulants: JSC1Avf, NU-LHT-1D, and CLDS-i, we developed a new high-fidelity lunar dust simulant named as BHLD20. And we concluded a methodology that soil and dust simulants can be produced by variations in portions of the overall procedure, whereby the properties of the products can be controlled by adjusting the feedstock preparation and heating process. The key ingredients of our innovative preparation route include: (1) plagioclase, used as a major material in preparing all kinds of lunar dust simulants; (2) a muffle furnace, applied to expediently enrich the glass phase in feedstock, with the production of some composite particles; (3) a one-step sand-milling technique, employed for mass pulverization without wasting feedstock; and (4) a particle dispersant, utilized to prevent the agglomeration in lunar dust simulant and retain the real particle size. Research activities in the development of BHLD20 can help solve the lunar dust problem.
1. Introduction Lunar surface is dusty, and flying dirt spreads everywhere, creating a permanent, levitated dust cloud around the moon (Horanyi et al., 2015). Especially near the sunrise, intensive dust storm forms in the lunar electric field (Grün et al., 2011). It is this abundant lunar dust (< 20 µm) that will be troublesome and have many negative effects on future astronaut's lunar explorations. According to the reports of the Apollo missions, the function of thermal-control systems, opticalimaging systems, spacesuits, and some mechanical facilities gradually degraded, due to the covering, adhering and abrasive effects of the ubiquitous dust. Nearly all the lunar dust problems are ascribed to the characteristics of lunar dust itself, especially with its possession of agglutinates and nanophase iron (np-Fe°) (Sen et al., 2011), high maturity (Taylor et al., 2001a), ultrafine particle size (Park et al., 2008), charging and floating properties (Abbas et al., 2010, 2007; Nemecek et al., 2011; Stubbs et al., 2006), adhesion and abrasion abilities (Kobrick et al., 2011; Walton, 2007), potential toxicity (Linnarsson et al., 2012), etc. It is essential to develop solutions for minimizing the influence of lunar dust on future lunar exploration programs. Using the real lunar sample for study is definitely an ideal
⁎
option. However, due to the precious nature of the Apollo lunar samples, it is not feasible to use sufficient quantities for many engineering studies; hence, the production of lunar soil and dust simulants becomes quite important (Liu and Taylor, 2011; Taylor et al., 2016). Thanks to the compatibility in geology between the Earth and its Moon, most lunar substances can be simulated using terrestrial materials. As a renewed interest in lunar exploration emerged at the beginning of this century, and with this a need for lunar soil and dust simulants began to appear (Liu and Taylor, 2011). Currently, three lunar dust simulants have been developed, i.e. JSC-1Avf (Park et al., 2008; Wallace et al., 2009) and NU-LHT-1D (Stoeser et al., 2008, 2010) from the U.S., and CLDS-i (Tang et al., 2017) from China. Detailed studies have shown that with the decreasing of grain size, the contents of Al2O3 and CaO (feldspathic components) increase in most lunar regolith samples, while the contents of FeO, MgO, and TiO2 (mafic components) decrease (Laul and Papike, 1980; Taylor et al., 2001a, 2001b, 2003). However, most previous lunar dust simulants were prepared from their basaltic or feldspathic soil origins. In this work, we will combine feldspathic raw material with a basaltic one, in order to prepare a new lunar dust simulant named as BHLD20. The agglutinate glass makes up
Corresponding author. Corresponding author at: School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China. E-mail addresses: [email protected] (M. Yi), [email protected] (Z. Shen).
⁎⁎
http://dx.doi.org/10.1016/j.pss.2017.04.010 Received 12 September 2016; Received in revised form 7 April 2017; Accepted 9 April 2017 Available online 13 April 2017 0032-0633/ © 2017 Elsevier Ltd. All rights reserved.
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
35–70% of the lunar dust (Taylor et al., 2001a, 2010), playing an important role in affecting lunar dust characteristics (Gustafson et al., 2007). Former endeavors to manufacture agglutinate simulants relied on specialized facilities and were of low yield (Sen et al., 2011; Weinstein and Wilson, 2013; Gustafson et al., 2011; Hung and McNatt, 2012). Present work will propose a convenient method by using a high-temperature muffle furnace and a cold-water basin, through which the abundance of glass phase or the maturity of BHLD20 can be controlled (partial melting). Since lunar dust simulant is a sort of ultrafine powder material, conventional dry milling and sieving methods used in preparing lunar soil simulant are no longer applicable and are of low yield as well (Basu et al., 2001; Graf, 1993; Liu and Taylor, 2011). In this work, we will apply wet sand-milling technique to make the mass production of lunar dust simulant possible. In order to prevent the violent agglomeration that happens in this ultrafine powder, we will first introduce dispersant into the preparation of lunar dust simulant, thus to avoid measuring error of particle size distribution (PSD). In the last part, we will demonstrate the intrinsic features of BHLD20, and making comparisons with lunar dust samples, especially in the aspects of PSD, particle morphology, modal abundance, and chemical composition. With the mission of collecting lunar sample for research, Chang’E-V probe is schemed to launch in the near future, and will land on the far side of the moon. Current studies on developing lunar dust simulant are definitely bound to help handle with that precious sample in an appropriate manner. Besides, high-fidelity lunar dust simulant can be used to emulate lunar cloudy environment, and help study the mechanisms by which lunar materials interact with extravehicular facilities as well as the human body. It is anticipated that the development of the new controllable lunar dust simulant BHLD20 will contribute a lot to the future lunar exploration.
Fig. 1. (a) Particle size distributions (PSD) of lunar dust samples (Park et al., 2008). Median particle size of Apollo 11 lunar dust sample 10084 is ~100 nm, and median particle size of Apollo 17 lunar dust sample 70051 is ~300 nm. (b) Differential PSD of JSC-1Avf: median particle size is 600–700 nm (Park et al., 2008). (c) Particle accumulative quantity percent (integral PSD) of JSC-1Avf, compared with those of the lunar dust samples (Park et al., 2008).
processes, lunar dust simulant JSC-1Avf can be obtained from JSC-1A. Median particle size of JSC-1Avf is 600–700 nm, larger than that of Apollo lunar dust samples (100–300 nm), as shown in Fig. 1 (Park et al., 2008).
2. Existing lunar dust simulants Numerous lunar regolith simulants have been developed so far, among which the JSC, NU-LHT, and CLRS (CAS) are the most complete series because they all have a dust level product, namely the JSC-1Avf, NU-LHT-1D and CLDS-i, respectively. Their brief information is shown in Table 1.
2.2. NU-LHT-1D NU-LHT-1D is developed by NASA Marshall Space Flight Center and United States Geological Survey, mainly for ground-based lunar highland researches (Liu and Taylor, 2011; Schrader et al., 2009). Feedstock of NU-LHT-1D is complex. It is a mixture of norite, anorthosite, and hartzburgite that are mined at Stillwater near Beartooth mountains, as well as some natural ilmenite. Minerals in these rocks include plagioclase, orthopyroxene, clinopyroxene, olivine, chromite, ilmenite, etc. The confected feedstock has made references to the Apollo 16 lunar samples (Stoeser et al., 2010). Because of the total absence of amorphous phase in the feedstock, it is indispensable to prepare the agglutinate analog and pure glass for all the NU-LHT products. Zybek Advanced Products Inc. (ZAP) is responsible for manufacturing the glass phase of NU-LHT-1D (Weinstein and Wilson, 2013). However, npFe° is not present in this product. Ball milled and wet-sieved product NU-LHT-1D has a grain size of < 36 µm (Stoeser et al., 2008), which is slightly larger than lunar dust standard < 20 µm.
2.1. JSC-1Avf JSC-1Avf is the first lunar dust simulant (< 20 µm). It is the finest portion of JSC-1A that has been developed by Orbital Technologies Corporation (ORBITEC) (Liu and Taylor, 2011; Gustafson et al., 2007; McKay et al., 1993). Feedstock for producing JSC-1Avf is mined from a basaltic pyroclastic sheet deposit at San Francisco volcanic field near Flagstaff, which contains volcanic glass, plagioclase, clinopyroxene, orthopyroxene, olivine, magnetite, ilmenite, and apatite. This volcanic tuff resembles some Apollo 14 and Apollo 17 lunar soil samples (Ray et al., 2010; Wallace et al., 2009). ORBITEC uses an impact mill to pulverize the feedstock and produce the lunar soil simulant JSC-1A. Besides, ORBITEC and Plasma Processes Inc. have developed specialized facilities to manufacture the glassy agglutinate analog respectively (Gustafson et al., 2011; Sen et al., 2011). Product analyses manifest that both approaches can provide satisfactory lunar agglutinate simulant with the inclusion of np-Fe°. Through ball milling and wet-sieving
2.3. CLDS-i CLDS-i is another lunar dust simulant that has been developed by Chinese Academy of Sciences and China National Astronomical Observatories (Tang et al., 2017; Zheng et al., 2009). It has a composition similar to JSC-1Avf, and JSC-1A actually. Feedstock of CLDS-i is scoria deposit that is mined from a volcanic field located in the northeastern China. Minerology and chemistry of the basaltic pyroclast are comparable with those of some Apollo 14, 15 soils, making such material an optimal choice in China to produce relevant lunar simulant (Liu et al., 2007). In order to increase the proportion of glass phase in the feedstock, they utilize magnetic separation method to
Table 1 Existing lunar dust simulants. Simulant
JSC-1Avf
NU-LHT-1D
CLDS-i
Reference sample Producer Available year
Apollo 14, 17 ORBITEC 2006
Apollo 16 NASA/USGS 2006
Apollo 14, 15 CAS 2017
18
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Table 2 Chemical composition of CLDS-i (Tang et al., 2017) compared with those of representative Apollo lunar dust samples (Laul and Papike, 1980; Hill et al., 2007). Sample
10084 < 10 µm
14163 < 10 µm
15271 < 10 µm
64501 < 10 µm
70051 < 45 µm
CLDS-i
SiO2 TiO2 Al2O3 Cr2O3 MgO CaO MnO FeO** Na2O K2O Total
41.30 7.30 16.30 0.29 7.20 12.70 0.18 15.10 0.47 0.16 101.00
48.50 1.70 19.0 0.19 8.00 11.30 0.12 9.20 0.71 0.59 99.31
46.00 1.50 19.80 0.30 8.70 12.30 0.13 10.30 0.50 0.23 99.76
45.60 0.45 27.40 0.10 4.30 16.10 0.06 4.40 0.47 0.15 99.03
41.10 4.51 18.60 – 9.00 11.80 0.16 11.90 0.28 0.10 97.45
49.99 1.22 14.09 – 8.16 7.17 0.11 11.53 2.78 1.23 94.17
enrich the inherent volcanic glass to some extent. Coarse glass-rich feedstock then is ground by a planetary ball mill and an ultrasonic crusher. The grinding process is conducted in liquid phase so that a freeze-drying technique is applied to obtain powder form. By means of pulse laser sputtering, grains in CLDS-i are at last coated with some npFe° globules specially (Tang et al., 2017, 2012). Testing results show that the median particle size of CLDS-i is about 500 nm, glass phase in CLDS-i is ~75%, and bulk chemistry is eligible according to Apollo lunar dust samples, as listed in Table 2. Fig. 3. (a) Photos of feedstock of lunar dust simulant BHLD20. (b) Elemental compositions of the scoria and plagioclase, compared with those of bulk 14163 soil sample and its agglutinate component.
3. Experimental details The purpose of this work is to improve the existing routes for the preparation of lunar dust simulant, and develop a new route for the controllable as well as massive production of lunar dust simulant. The outline of developing lunar dust simulant BHLD20 is shown in Fig. 2, whose details will be discussed below.
Fig. 3(b). Both the compositions of scoria and plagioclase are comparable with those of lunar soil sample 14163 and its agglutinate component (Walker and Papike, 1981). With introducing mineral plagioclase that is abundant in lunar dust, theoretically the fidelity of dust simulant gets higher. Moreover, it provides possibility of preparing highland type dust simulant along the same route.
3.1. Preparation of feedstock
3.2. Enhancing the glass phase content
Feedstock of lunar dust simulant BHLD20 is a mixture of basaltic scoria and anorthositic plagioclase, as shown in Fig. 3(a). The scoria (top left of Fig. 3(a)) is mined from a volcanic field in Huinan, China, and its mineralogy and chemistry have been testified close to some Apollo 14 lunar soils (Liu et al., 2007). As mentioned above, most lunar dust samples are more feldspathic than coarser soils. Hence, by introducing feldspathic minerals into basaltic feedstock to improve the precision of lunar dust simulant is a reasonable attempt (Taylor et al., 2001a). All kinds of feldspars are available at Taihang Mountains in Lingshou, China. By blending and melting the anorthite with albite in a proper ratio, anorthositic plagioclase (anorthite > 50%) can be acquired (bottom left of Fig. 3(a)). Though it is a terrestrial version, as the scoria, it has certain similarities to lunar feldspars compared with other minerals. Bulk chemistries of BHLD20 raw materials are shown in
In this work, high-temperature muffle furnace is used to increase the amount of glass phase in BHLD20 with some composite particles. As we know, perfect agglutinates on the moon are highly vesicular with abundant mineral fragments and np-Fe° entrained in impact glasses (Heiken et al., 1991). Given that the lunar agglutinates are created in specific space environment, partial melting is crucial for reproducing this heterogeneous material (Ray et al., 2010; Sen et al., 2011). According to Bowen's reaction series (Bowen, 1922), basic mineral has higher melting point than intermediate or acid one, as is the case in plagioclase. While in the feedstock of BHLD20, there coexists basic minerals (e.g. anorthite, pyroxene), acid minerals (e.g. albite) and ultrabasic minerals (e.g. olivine). Hence both the heating temperature
Fig. 2. Preparation route and major facilities for producing lunar dust simulant BHLD20.
19
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Fig. 4. The XRD and SEM results of representative melted products. (a) Pristine feedstock without heat treatment. And melted products produced by heating at (b) 1200 °C for 20 min, (c) 1200 °C for 30 min, and (d) 1200 °C for 2 h. Red boxes in the SEM images in (c) and (d) indicate a few glass-rich composite particles that are highly irregular and in agglomerate form. (b) has so many glass-rich composite particles that red boxes are not assigned. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
and time should be carefully chosen to control the extent of crystalline phase melting to amorphous glass. In our experiment, feedstock comprised of scoria and plagioclase was milled for uniform mixing before heating. Then the mixture was heated at a temperature from 1000 °C to 1300 °C for 10 min to 120 min. To avoid recrystallization, each molten product was thrown into a water basin as soon as heat treatment was finished. The glass-rich products were dried for further characterization. Based on the XRD patterns, optical and SEM images of all the products, we found that the abundance of amorphous phase or the maturity is indeed controllable by adjusting the heating temperature and time. Representative XRD, optical and SEM results of the melted products are shown in Fig. 4. Melting experiment reveals that not high enough temperature or short heating time leads to low glass phase yield (Fig. 4(a)), yet too high temperature and too long heating time generate nearly all pure glass (Fig. 4(c)(d)). The product obtained at 1200 °C for 20 min (Fig. 4(b)) is believed to be reasonable; because it has a moderate amount of glass phase along with a large number of irregular and heterogeneous suspected “agglutinates”, as the features of real lunar dust (Taylor et al., 2001a, 2001b). However, more careful observation shows that such suspected “agglutinates” are only a sort of glass-rich composite particles, in which vesicular structures are not that abundant as well as the np-Fe° globules are absent. Even so, it is the total glass phase content that contributes a lot to general engineering uses (Liu and Taylor, 2011). The degree of feedstock vitrified by muffle furnace as a function of heating temperature and heating time is summarized in Fig. 5. Through heat treatment, the abundance of glass phase in BHLD20 can be regulated and determined. It should be noted
Fig. 5. Results of producing lunar amorphous analog by muffle furnace. Black and grey dots display different heating conditions in the melting experiment. “feedstock” here means melted products that are devoid of man-made amorphous phase. “partial-melted products” represents melted products that have a moderate amount of glass phase as well as a great number of glass-rich composite particles. “pure glass” represents melted products that have been overheated.
that once the melted product being pulverized, they will split into smaller crystals, pure glasses, and glass-rich composite particles. Among which the latter two, i.e. the amorphous components are dominant. The glass-rich material prepared here is an ideal intermediate product for developing dust simulant BHLD20. 20
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
TEM image in Fig. 6(a). Therefore, the median particle size was significantly increased to ~ 2.3 µm (Fig. 6(b)). Here we tried to use dispersant to make the submicron particles better dispersed. By a few trials with different dispersant candidates, we found that the silane coupling agent A151 (Vinyltriethoxysilane) performed the best. After the slurry of lunar dust simulant with A151 was sonicated and stirred, the particle size approached to its original level (200–300 nm), as shown in Fig. 6(c). Well dispersed slurry was then dried to obtain the dispersive ultrafine powder. Fig. 6(d) gives a typical SEM image of the dried powder in the case of 0.5 wt% A151 and 8 h sonication. We found that after drying, only a few soft agglomerates existed and they could be easily crumbed with fingertips. In order to satisfy the ground-based applications which require a dusty cloud environment, the dried ultrafine powder was subsequently treated with a jet mill to ensure that all the soft agglomerates were fully pulverized. Finally, a rather loose lunar dust simulant, i.e. BHLD20, came into being, as shown in Fig. 7(a).
As for lunar np-Fe°, its forming mechanism is still not quite clear, but it contributes to the optical, magnetic, and toxic properties of lunar regolith (Keller and McKay, 1993, 1997; Pieters et al., 2000; Sasaki et al., 2001; Wallace et al., 2010). While on the earth, lunar simulant with this active metallic iron will be sensitive to the atmosphere and quickly become an oxygen “getter”. Hence it is not easy to reserve the reductive np-Fe° in terrestrial tests. Recently, it has been confirmed that the activities preparing np-Fe° in lunar simulant is costly and laborintensive, with rather limited application prospect (Taylor et al., 2016). Thereby in view of general uses, no single-domain np-Fe° is expressly prepared or introduced into BHLD20. Even so, BHLD20 has certain magnetic properties because of the presence of terrestrial magnetite, which is similar to the case of JSC-1A (Liu and Taylor, 2011).
3.3. Pulverization and particle dispersion In this study, a sand-milling machine (1 L) was employed to straight grind the above intermediate product (1200 °C-20 min partial-melted simulant) down to ultrafine level in deionized water without any sieving process. After the grinding process, a slurry of BHLD20 was acquired. And the solid content of the slurry is about 30–50%. Via a Malvern laser particle sizer, the PSD of the slurry product was measured right after the milling process. Result showed that the median particle size was about 285 nm, which matched well with the size of wet-sieved lunar dust samples. This size distribution was better than that of any previous lunar dust simulant. However, violent agglomerate induced submicron particles to form particle clusters very quickly, as shown the
4. Results and discussion To evaluate the fidelity of a lunar dust simulant, it is necessary to compare it with the lunar dust samples, especially in the aspects of PSD, particle morphology, modal abundance, and bulk chemistry (Liu and Taylor, 2011; Taylor et al., 2016). The similar characterization methods for lunar samples were applied to BHLD20.
Fig. 6. (a) TEM image of dried BHLD20 without dispersion. Red circles indicate agglomerate clusters consisting of numerous smaller grains. (b) Particle agglomeration leading to an enlarged PSD result (from the black curve to the blue). (c) Particle aggregation was mitigated by introducing dispersant A151, and A151 of 0.5 wt% concentration along with 8 h ultrasonication performs the best. (d) SEM image of the dried and well dispersed BHLD20 product. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
21
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Fig. 1(a). It must be emphasized that our PSD measurements were made with a laser technique that does not reproduce that used in the Apollo samples’ PSD measurements (Taylor et al., 2016). In this way, actually the PSD of BHLD20 we acquired is a little finer than that of a wet-sieved product. Fortunately, the PSD can also be expediently adjusted to whatever level through the straight sand-milling method, making the PSD another controllable factor during the development of lunar dust simulant. Although laser technique is a modern method characterizing particle size, wet-sieving is still a suitable technique for reserving the nature of lunar dust. Owing to the long-time “space gardening” on the moon, the particle size level is corresponding to the characteristics of the lunar material (Laul and Papike, 1980). Therefore, future lunar samples are not suggested to be straight comminuted to dust level, but suggested to be sieved carefully in consideration of the diversity among dust, soil, and rock. 4.2. Morphology When it comes to the morphology or shape information of particles in lunar regolith, we always refer to their 2D projection (Liu et al., 2008). Fig. 8 shows SEM images of five representative particles from BHLD20. In all kinds of particles, the glass-rich composite particle is the most irregular one with considerable specific surface area. An appreciable quantity of glass beads reside in BHLD20, which take up a great part especially on the nanoscale. Complexity and aspect ratio are the most significant geometrical algorithms to quantify the morphological feature of lunar grains (Rickman et al., 2012). Their expressions are shown in Fig. 8 and are explained via particle Fig. 8(b), in which a is the half major axis of an equivalent ellipse, b is the half minor axis, C is the perimeter of a particle's 2D projection, and S is the area of the projection. Shape information of BHLD20 is calculated and listed in Table 3. The averages are derived from a SEM image of BHLD20. The aspect ratio of BHLD20 is smaller than lunar dust samples’ average while the complexity is bigger, meaning that particles in BHLD20 are more flat in profile, but not as rough as lunar dust samples. One reason for this is the lack of massive vesicular structures that lunar agglutinates obtained from the micrometeorite bombardments on lunar surface. (Liu et al., 2008).
Fig. 7. (a) Photo of lunar dust simulant BHLD20. (b) PSD of BHLD20 measured by laser particle analyzer. Black line is the differential distribution after coordinate transformation to match the PSD of Apollo lunar dust samples, and pink line is the integral distribution. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
4.1. Particle size distribution (PSD) Laser particle analyzer was used to measure the PSD of both BHLD20 powder and BHLD20 slurry. Differential PSD result of BHLD20 powder is close to the black curve in Fig. 6(c). After a coordinate transformation, final PSD of BHLD20 in accord with Fig. 1 is illustrated by Fig. 7(b). All grains are smaller than 20 µm and the median particle size drops to an unprecedented value: 250–300 nm, quite similar to the size of wet-sieved Apollo dust samples shown in
4.3. Modal abundance Modal abundance refers to the quantities of diverse minerals and glass phase in a geologic sample, in this case, a lunar material (Rickman et al., 2011). According to the feedstock constituents (Liu et al., 2007) and the XRD result of the melted product after heat treatment, modal constituents in BHLD20 include glass-rich composite particles, volcanic
Fig. 8. Representative particles in BHLD20 and the algorithms to quantify their shape information. (a)(b) Glass-rich composite particles that are irregular but devoid of vesicles. (c)(d)(e) Glass beads that are smooth and regular. (b) is chosen to explain the method characterizing the morphology of a single particle.
22
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Given the modal abundance and chemical composition of BHLD20 in Fig. 9, we suggest that a mare dust simulant can be made by introducing more Ti-magnetite/ilmenite and glass components into BHLD20 (Weiblen et al., 1990); however, this also depends upon whether we are referring to high-Ti mare (Apollo 11 and 17) or lowTi mare (Apollo 12 and 15). Whereas the lunar highland dust simulant can be made by introducing more plagioclase. The chemistry of the glass phases can be different from place to place, but it can be adjusted in the feedstock preparation process, before heat treatment. However, each Apollo lunar sample represents only a limited lunar surface. No simulant can represent the whole lunar mare or highland. What we can do is to try our best to approach more close to either the lunar mare samples or the lunar highland ones. It seems that the composition discrepancies in dust samples are not as large as those in soils, probably due to the selective comminution, lateral mixing, and preferential melting of space weathering (Taylor et al., 2010). Therefore, as an “intermediate” between mare and highland dust, BHLD20 is generally close to most lunar dust samples. Moreover, its high-glass abundance makes it a competent simulant for many ground-based geotechnical applications.
Table 3 Morphological result of BHLD20 compared with those of Apollo lunar samples (Liu et al., 2008). Parameter
Aspect ratio
Complexity
BHLD20 Lunar sample
0.58 0.70
1.05 1.15
glass, plagioclase, olivine, pyroxene, and other minor minerals. In this study, content of glass phase in BHLD20 can be controlled from 25% to nearly 100% by adjusting the heating condition. Since the impact glass in real lunar dust ranges from 35% to 70% (Taylor et al., 2001a, 2010), we designate BHLD20 containing 55% glass phase as the standard product, in which glass-rich composite particles is ~35%, volcanic glass is ~20%. The standard product also contains ~25% plagioclase as well as ~20% other minerals. Apollo 16 highland samples contain large (> 70%) plagioclase (~5 wt% FeO), and represent the soil fraction that occurs in > 80% of the Moon. The Mare samples that occur in the remainder < 20% of the Moon's soil have < 40% plagioclase and about 15 wt% FeO. The lunar dust simulant that we have produced refers to the neither good highland nor mare dust, as shown in Fig. 9(a). However, it is similar to JSC-1Avf lunar dust simulant, which was made primarily for its geotechnical properties, not only the chemistry or mineralogy. The importance of our process for making BHLD20 is that the mineralogy can be easily changed in the production process such that we can make the dust product similar to any dust composition on the Moon. (Taylor et al., 2001a, 2010, 2016).
5. Summary In this work, we put forward an improved route for developing lunar dust simulants, whereby we can prepare a new high-fidelity lunar dust simulant named as BHLD20. In order to more realistically approach the properties of real lunar dust, we introduce plagioclase as a major feedstock. The content of the glass phase in BHLD20 can be modified by use of a muffle furnace to simplify and control the heating process. Instead of wet-sieving, a sand-milling technique was applied for one-step pulverization, guaranteeing a stable chemistry and a high yield of product. The agglomeration of lunar dust simulant was eliminated by introducing an appropriate dispersant. In this way, the finer-grain size of the simulant was realized. However, it must be pointed out that our PSD measurements were made with a laser technique that does not reproduce that used in Apollo samples’ PSD measurements. By diverse characterization methods, nearly all the intrinsic properties of BHLD20 were proved to be close to some of the Apollo lunar dust samples. By variations in the step-wise procedure of producing lunar dust/ soil simulants – i.e., feedstock preparation and heat treatment processes, it is possible to modify the intrinsic properties of the products. Present work proposes an integrated route for preparing lunar dust simulant of different types. It is hopeful that the type of BHLD20 can be controlled from lunar mare to the highland, and from immature to mature. BHLD20 is attractive for a range of ground-based engineering studies related to solving lunar dust problem. And as a precursor prior
4.4. Chemical composition A variety of testing techniques have been applied to the characterization of the bulk chemistry of lunar materials, and X-ray fluorescence spectrometer (XRF) analysis is one of them (Hill et al., 2007). Major rock-forming oxides in BHLD20 tested by XRF are presented in Table 4. From chemical prospective, lunar dust simulant BHLD20 approaches to some Apollo 14 dust samples, whose chemistry lie halfway between lunar feldspathic highland and basaltic mare, but closer to the latter except mafic elements, see details in Fig. 9(b). Total iron oxides in BHLD20 is about 7.93 wt%, which again demonstrates that this BHLD20 product is neither a mare simulant, nor a highland one (Taylor et al., 2001a, 2010). These iron oxides in BHLD20 include Fe2O3 which will not be found on the moon (Lucey et al., 1995). Because of the intrinsic difference in geology between earth material and lunar material, the abundances of SiO2, Na2O, K2O in BHLD20 is slightly higher than those of lunar dust samples. TiO2 in BHLD20 is rare so that it is temporarily a sort of low-Ti lunar dust simulant with an intermediate composition in the current study.
Fig. 9. (a) Modal abundance of BHLD20. (b) Chemical composition of BHLD20. Both manifest that BHLD20 simulant is consistent with most Apollo lunar dust samples (< 10 µm) (Taylor et al., 2001a, 2010).
23
Planetary and Space Science 141 (2017) 17–24
H. Sun et al.
Table 4 Chemical composition of BHLD20. BHLD20
SiO2
TiO2
Al2O3
Cr2O3
MgO
CaO
MnO
FeO**
Na2O
K2O
Total
Wt%
50.17
1.18
17.21
0.31
3.34
9.41
0.12
7.93
5.59
1.67
96.93
McKay D.S., Carter J.L., Boles W.W., Allen C.C., Allton J.H., 1993. In: Proceedings of the 24th Lunar and Planetary Science Conference, pp. 963–964. Nemecek, Z., Pavlu, J., Safrankova, J., Beranek, M., Richterova, I., Vaverka, J., Mann, I., 2011. Lunar dust grain charging by electron impact: dependence of the surface potential on the grain size. Astrophys. J. 738, 14–20. Park, J., Liu, Y., Kihm, K.D., Taylor, L.A., 2008. Characterization of lunar dust for toxicological studies. I: particle size distribution. J. Aerosp. Eng. 21, 266–271. Pieters, C.M., Taylor, L.A., Noble, S.K., Keller, L.P., Hapke, B., Morris, R.V., Allen, C.C., McKay, D.S., Wentworth, S., 2000. Space weathering on airless bodies: resolving a mystery with lunar samples. Meteorit. Planet. Sci. 35, 1101–1107. Ray, C.S., Reis, S.T., Sen, S., O’Dell, J.S., 2010. JSC-1A lunar soil simulant: characterization, glass formation, and selected glass properties. J. Non-Cryst. Solids 356, 2369–2374. Rickman, D., Immer, C., Metzger, P., Dixon, E., Pendleton, M., Edmunson, J., 2012. Particle shape in simulants of the Lunar regolith. J. Sediment. Res. 82, 823–832. Rickman D.L., Stoeser D.B., Benzel W.M., Schrader C.M., Edmunson J.E., 2011. Notes on lithology, mineralogy, and production for lunar simulants. In: National Aeronautics and Space Administration. NASA/TM—2011–216454. Sasaki, S., Nakamura, K., Hamabe, Y., Kurahashi, E., Hiroi, T., 2001. Production of iron nanoparticles by laser irradiation in a simulation of lunar-like space weathering. Nature 410, 555–557. Schrader C.M., Rickman D.L., Mclemore C.A., Fikes J.C., Stoeser D.B., Wentworth S.J., McKay D.S., 2009. Lunar regolith characterization for simulant design and evaluation using figure of merit algorithms. In: Proceedings of the 47th AIAA Aerospace Sciences Meeting. AIAA 2009–2755. Sen, S., Butts, D., Ray, C.S., Thompson, G.B., Morris, R.A., O’Dell, J.S., 2011. Production of high fidelity lunar agglutinate simulant. Adv. Space Res. 47, 1912–1921. Stoeser D., Wilson S., Weinstein M., Rickman D., Lowers H., Meeker G., Schrader C., McLemore C., Fikes J., 2008. The LHT (Lunar Highlands Type) regolith simulant series. In: Proceedings of The Geological Society of America (GSA) 2008 Joint Annual Meeting. Stoeser D., Wilson S., Rickman D., 2010. Design and specifications for the highland regolith prototype simulants NU-LHT-1M and -2M. National Aeronautics and Space Administration, NASA/TM—2010–216438. Stubbs, T.J., Vondrak, R.R., Farrell, W.M., 2006. A dynamic fountain model for lunar dust. Adv. Space Res. 37, 59–66. Tang, H., Wang, S., Li, X., 2012. Simulation of nanophase iron production in lunar space weathering. Planet. Space Sci. 60, 322–327. Tang, H., Li, X., Zhang, S., Wang, S., Liu, J., Li, S., Li, Y., Wu, Y., 2017. A lunar dust simulant: clds-i. Adv. Space Res. 59, 1156–1160. Taylor, L.A., Pieters, C.M., Keller, L.P., Morris, R.V., McKay, D.S., 2001a. Lunar Mare Soils: space weathering and the major effects of surface-correlated nanophase Fe. J. Geophys. Res. 106, 27985–27999. Taylor, L.A., Pieters, C.M., Keller, L.P., Morris, R.V., McKay, D.S., Patchen, A., Wentworth, S., 2001b. The effects of space weathering on Apollo 17 mare soils: petrographic and chemical characterization. Meteorit. Planet. Sci. 36, 285–299. Taylor L.A., Pieters C.M., Patchen A., Taylor D.H., Morris R.V., Keller L.P., McKay D.S., 2003. Mineralogical Characterization of Lunar Highland Soils. In: Proceedings of the 34th Lunar and Planetary Science Conference. Abstract no. 1774. Taylor, L.A., Pieters, C.M., Patchen, A., Taylor, D.S., Morris, R.V., Keller, L.P., McKay, D.S., 2010. Mineralogical and chemical characterization of lunar highland soils: insights into the space weathering of soils on airless bodies. J. Geophys. Res. 115, 481–492. Taylor, L.A., Pieters, C.M., Britt, D., 2016. Evaluations of lunar regolith simulants. Planet. Space Sci. 126, 1–7. Walker R.J., Papike J.J., 1981. The relationship of the lunar regolith less than 10 μm fraction and agglutinates. Part II: Chemical composition of agglutinate glass as a test of the fusion of the finest fraction (F3) model. In: Proceedings of the 12th Lunar and Planetary Science Conference, pp. 421–432. Wallace, W.T., Taylor, L.A., Liu, Y., Cooper, B.L., McKay, D.S., Chen, B., Jeevarajan, A.S., 2009. Lunar dust and lunar simulant activation and monitoring. Meteorit. Planet. Sci. 44, 961–970. Wallace, W.T., Phillips, C.J., Jeevarajan, A.S., Chen, B., Taylor, L.A., 2010. Nanophase iron-enhanced chemical reactivity of ground lunar soil. Earth Planet. Sci. Lett. 295, 571–577. Walton O.R., 2007. Adhesion of lunar dust. National Aeronautics and Space Administration, NASA/CR—2007–214685. Weiblen P., Murawa M., Reid K., 1990. Preparation of Simulants for Lunar Surface Materials. In: Proceedings of the American Society of Civil Engineers in Space II, pp. 98–106. Weinstein M., Wilson S.A., 2013. Apparatus and Method for Producing a Lunar Agglutinate Simulant. US patent, US008610024. Zheng, Y., Wang, S., Ouyang, Z., Zou, Y., Liu, J., Li, C., Li, X., Feng, J., 2009. CAS-1 lunar soil simulant. Adv. Space Res. 43, 448–454.
to Chang’E-V lunar sample, the practical research activities on BHLD20 can make a significant contribution to future lunar dust sample management, especially in the pulverization and characterization aspects. Acknowledgements The authors would like to thank Prof. Larry Taylor (Tennessee) and the anonymous reviewers for their constructive suggestions and language polish of the manuscript. We gratefully acknowledge the China Academy of Space Technology and the China National Astronomical Observatories for their constructive suggestions. We thank Dongguan Longly Machinery Limited Company, which facilitated part of the research. Funding for the research presented in this paper was provided by Beijing Natural Science Foundation (2132025), and Specialized Research Fund for the Doctoral Program of Higher Education (20131102110016). References Abbas, M.M., Tankosic, D., Craven, P.D., Spann, J.F., LeClair, A., West, E.A., 2007. Lunar dust charging by photoelectric emissions. Planet. Space Sci. 55, 953–965. Abbas, M.M., Tankosic, D., Craven, P.D., LeClair, A.C., Spann, J.F., 2010. Lunar dust grain charging by electron impact: complex role of secondary electron emissions in space environments. Astrophys. J. 718, 795–809. Basu, A., Wentworth, S.J., McKay, D.S., 2001. Submillimeter grain-size distribution of Apollo 11 soil 10084. Meteorit. Planet. Sci. 36, 177–181. Bowen, N.L., 1922. The reaction principle in petrogenesis. J. Geol. 30, 177–198. Graf, J.C., 1993. Lunar Soils Grain Size Catalog. NASA Reference Publication 1265, Houston, Texas, USA (466 pp). Grün, E., Horanyi, M., Sternovsky, Z., 2011. The lunar dust environment. Planet. Space Sci. 59, 1672–1680. Gustafson R.J., White B.C., Gustafson M.A., Fournelle J., 2007. Development of a lunar agglutinate simulant. In: Proceedings, Space Resources Roundtable VIII: Program and Abstracts (LPI Contribution No. 1332), pp. 25–26. Gustafson R.J., Gustafson M.A., White B.C., 2011. Process to Create Simulated Lunar Agglutinate Particles. US patent, US8066796. Heiken, G.H., Vaniman, D.T., French, B.M., 1991. Lunar Sourcebook: A User's Guide to the Moon. Cambridge University Press, Cambridge, pp. 296–302. Hill, E., Mellin, M.J., Deane, B., Liu, Y., Taylor, L.A., 2007. Apollo sample 70051 and high- and low-Ti lunar soil simulants MLS-1A and JSC-1A: implications for future lunar exploration. J. Geophys. Res. 112, 273–300. Horanyi, M., Szalay, J.R., Kempf, S., Schmidt, J., Grun, E., Srama, R., Sternovsky, Z., 2015. A permanent, asymmetric dust cloud around the Moon. Nature 522, 324–326. Hung, C., McNatt J., 2012. Lunar Dust Simulant Containing Nanophase Iron and Method for Making the Same. US patent, US008283172. Keller, L.P., McKay, D.S., 1993. Discovery of vapor deposits in the lunar regolith. Science 261 (5126), 1305–1307. Keller, L.P., McKay, D.S., 1997. The nature and origin of rims on lunar soil grains. Geochim. Cosmochim. Acta 61 (11), 2331–2341. Kobrick R.L., Klaus D.M., Street K.W., 2011. Defining an abrasion index for lunar surface systems as a function of dust interaction modes and variable concentration zones. National Aeronautics and Space Administration. NASA/TM—2010–216792. Laul J.C., Papike J.J., 1980. The lunar regolith: Comparative chemistry of the Apollo sites. In: Proceedings of the 11th Lunar and Planetary Science Conference, pp. 1307–1340. Linnarsson, D., Carpenter, J., Fubini, B., Gerde, P., Karlsson, L.L., Loftus, D.J., Prisk, G.K., Staufer, U., Tranfield, E.M., van Westrenen, W., 2012. Toxicity of lunar dust. Planet. Space Sci. 74, 57–71. Liu, C., Wang, S., Feng, J., Li, X., Fu, S., Ouyang, Z., Zheng, Y., 2007. The geochemistry evidence for selecting the suitable raw material in China to simulate the low titanium lunar soil from lunar-sea basalt. J. Mineral. Petrol. 27, 28–33. Liu, Y., Taylor, L.A., 2011. Characterization of lunar dust and a synopsis of available lunar simulants. Planet. Space Sci. 59, 1769–1783. Liu, Y., Park, J., Schnare, D., Hill, E., Taylor, L.A., 2008. Characterization of lunar dust for toxicological studies. II: texture and shape characteristics. J. Aerosp. Eng. 21, 272–279. Lucey, P.G., Taylor, G.J., Malaret, E., 1995. Abundance and distribution of iron on the moon. Science 268, 1150–1153.
24