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DOE OSTI2020

Materials Data on Sr(AsO3)2 by Materials Project

SrAs2O6 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Sr2+ is bonded to six equivalent O2- atoms to form distorted SrO6 pentagonal pyramids that share corners with twelve equivalent AsO6 octahedra. The corner-sharing octahedral tilt angles are 53°. All Sr–O bond lengths are 2.54 Å. As5+ is bonded to six equivalent O2- atoms to form AsO6 octahedra that share corners with six equivalent SrO6 pentagonal pyramids and edges with three equivalent AsO6 octahedra. All As–O bond lengths are 1.87 Å. O2- is bonded in a distorted trigonal planar geometry to one Sr2+ and two equivalent As5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(GaSe2)2 by Materials Project

SrGa2Se4 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.29 Å) and four longer (3.32 Å) Sr–Se bond lengths. Ga3+ is bonded to four Se2- atoms to form edge-sharing GaSe4 tetrahedra. There are a spread of Ga–Se bond distances ranging from 2.43–2.47 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Ga3+ atoms. In the second Se2- site, Se2- is bonded to two equivalent Sr2+ and two equivalent Ga3+ atoms to form a mixture of distorted edge and corner-sharing SeSr2Ga2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(CoSi)2 by Materials Project

SrCo2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr2+ is bonded in a body-centered cubic geometry to eight equivalent Si4- atoms. All Sr–Si bond lengths are 3.21 Å. Co3+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing CoSi4 tetrahedra. All Co–Si bond lengths are 2.27 Å. Si4- is bonded in a 8-coordinate geometry to four equivalent Sr2+ and four equivalent Co3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(NCl2)2 by Materials Project

SrCl4N2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional and consists of four ammonia molecules and one SrCl4 framework. In the SrCl4 framework, Sr2+ is bonded in a body-centered cubic geometry to eight equivalent Cl1- atoms. All Sr–Cl bond lengths are 2.98 Å. Cl1- is bonded in a linear geometry to two equivalent Sr2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AuF6)2 by Materials Project

SrSr3(AuF6)8 crystallizes in the cubic P-43m space group. The structure is three-dimensional and consists of one strontium molecule and one Sr3(AuF6)8 framework. In the Sr3(AuF6)8 framework, Sr2+ is bonded to eight F1- atoms to form distorted SrF8 hexagonal bipyramids that share corners with eight AuF6 octahedra. The corner-sharing octahedra tilt angles range from 27–29°. There are four shorter (2.65 Å) and four longer (2.66 Å) Sr–F bond lengths. There are two inequivalent Au5+ sites. In the first Au5+ site, Au5+ is bonded to six F1- atoms to form AuF6 octahedra that share corners with three equivalent SrF8 hexagonal bipyramids. There is three shorter (1.91 Å) and three longer (1.98 Å) Au–F bond length. In the second Au5+ site, Au5+ is bonded to six F1- atoms to form AuF6 octahedra that share corners with three equivalent SrF8 hexagonal bipyramids. There is three shorter (1.91 Å) and three longer (1.98 Å) Au–F bond length. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Sr2+ and one Au5+ atom. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Sr2+ and one Au5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one Au5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one Au5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(TmS2)2 by Materials Project

SrTm2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.08–3.28 Å. There are two inequivalent Tm3+ sites. In the first Tm3+ site, Tm3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedra tilt angles range from 48–61°. There are a spread of Tm–S bond distances ranging from 2.68–2.74 Å. In the second Tm3+ site, Tm3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedra tilt angles range from 48–61°. There are a spread of Tm–S bond distances ranging from 2.66–2.74 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Sr2+ and three Tm3+ atoms. In the second S2- site, S2- is bonded to two equivalent Sr2+ and three equivalent Tm3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Tm3 square pyramids. In the third S2- site, S2- is bonded to two equivalent Sr2+ and three Tm3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Tm3 trigonal bipyramids. In the fourth S2- site, S2- is bonded to two equivalent Sr2+ and three equivalent Tm3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Tm3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(LuS2)2 by Materials Project

SrLu2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.07–3.27 Å. There are two inequivalent Lu3+ sites. In the first Lu3+ site, Lu3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing LuS6 octahedra. The corner-sharing octahedra tilt angles range from 48–61°. There are a spread of Lu–S bond distances ranging from 2.66–2.73 Å. In the second Lu3+ site, Lu3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing LuS6 octahedra. The corner-sharing octahedra tilt angles range from 48–61°. There are a spread of Lu–S bond distances ranging from 2.65–2.73 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Sr2+ and three Lu3+ atoms. In the second S2- site, S2- is bonded to two equivalent Sr2+ and three equivalent Lu3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Lu3 square pyramids. In the third S2- site, S2- is bonded to two equivalent Sr2+ and three Lu3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Lu3 trigonal bipyramids. In the fourth S2- site, S2- is bonded to two equivalent Sr2+ and three equivalent Lu3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Lu3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(InP)2 by Materials Project

SrIn2P2 crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two SrIn2P2 sheets oriented in the (0, 0, 1) direction. Sr2+ is bonded to six equivalent P3- atoms to form edge-sharing SrP6 octahedra. All Sr–P bond lengths are 3.09 Å. In2+ is bonded in a trigonal non-coplanar geometry to three equivalent P3- atoms. All In–P bond lengths are 2.66 Å. P3- is bonded to three equivalent Sr2+ and three equivalent In2+ atoms to form a mixture of edge and corner-sharing PSr3In3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(CO2)2 by Materials Project

SrC2O4 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is one-dimensional and consists of two SrC2O4 ribbons oriented in the (1, 0, 0) direction. Sr2+ is bonded in a 2-coordinate geometry to four O2- atoms. There are a spread of Sr–O bond distances ranging from 2.42–2.94 Å. There are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a linear geometry to two O2- atoms. Both C–O bond lengths are 1.18 Å. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.31 Å) and one longer (1.33 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+ and one C3+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C3+ atom. In the third O2- site, O2- is bonded in a water-like geometry to one Sr2+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Sr2+ and one C3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(SiPd)6 by Materials Project

Sr(PdSi)6 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional and consists of four strontium molecules and one PdSi framework. In the PdSi framework, there are two inequivalent Pd+2.33+ sites. In the first Pd+2.33+ site, Pd+2.33+ is bonded in a 5-coordinate geometry to five Si+2.67- atoms. There are a spread of Pd–Si bond distances ranging from 2.45–2.62 Å. In the second Pd+2.33+ site, Pd+2.33+ is bonded in a 7-coordinate geometry to seven Si+2.67- atoms. There are a spread of Pd–Si bond distances ranging from 2.44–2.98 Å. There are two inequivalent Si+2.67- sites. In the first Si+2.67- site, Si+2.67- is bonded in a 5-coordinate geometry to six Pd+2.33+ atoms. In the second Si+2.67- site, Si+2.67- is bonded in a 4-coordinate geometry to five Pd+2.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AlS2)2 by Materials Project

SrAl2S4 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.15 Å) and four longer (3.19 Å) Sr–S bond lengths. Al3+ is bonded to four S2- atoms to form edge-sharing AlS4 tetrahedra. There are a spread of Al–S bond distances ranging from 2.26–2.30 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Al3+ atoms. In the second S2- site, S2- is bonded to two equivalent Sr2+ and two equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing SSr2Al2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AsPt)2 by Materials Project

SrPt2As2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight Pt2- atoms. There are four shorter (3.39 Å) and four longer (3.46 Å) Sr–Pt bond lengths. There are two inequivalent Pt2- sites. In the first Pt2- site, Pt2- is bonded in a 8-coordinate geometry to four equivalent Sr2+ and four equivalent As1+ atoms. All Pt–As bond lengths are 2.61 Å. In the second Pt2- site, Pt2- is bonded in a 9-coordinate geometry to four equivalent Sr2+ and five As1+ atoms. There are one shorter (2.53 Å) and four longer (2.56 Å) Pt–As bond lengths. There are two inequivalent As1+ sites. In the first As1+ site, As1+ is bonded in a 5-coordinate geometry to five Pt2- atoms. In the second As1+ site, As1+ is bonded to four equivalent Pt2- atoms to form a mixture of distorted corner and edge-sharing AsPt4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(FeSb3)4 by Materials Project

SrFe4Sb12 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. Sr2+ is bonded to twelve equivalent Sb1- atoms to form SrSb12 cuboctahedra that share faces with eight equivalent FeSb6 octahedra. All Sr–Sb bond lengths are 3.44 Å. Fe+2.50+ is bonded to six equivalent Sb1- atoms to form FeSb6 octahedra that share corners with six equivalent FeSb6 octahedra and faces with two equivalent SrSb12 cuboctahedra. The corner-sharing octahedral tilt angles are 52°. All Fe–Sb bond lengths are 2.57 Å. Sb1- is bonded in a 2-coordinate geometry to one Sr2+, two equivalent Fe+2.50+, and two equivalent Sb1- atoms. There are one shorter (3.00 Å) and one longer (3.02 Å) Sb–Sb bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(CO2)2 by Materials Project

SrC2O4 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Sr2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sr–O bond distances ranging from 2.46–2.74 Å. There are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.28 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.26 Å) and one longer (1.28 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C3+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+ and one C3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(Ag2Sb)2 by Materials Project

SrAg4Sb2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Sr2+ is bonded to six equivalent Sb3- atoms to form edge-sharing SrSb6 octahedra. All Sr–Sb bond lengths are 3.44 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 1-coordinate geometry to six Ag1+ and four equivalent Sb3- atoms. There are three shorter (2.97 Å) and three longer (3.05 Å) Ag–Ag bond lengths. There are one shorter (2.86 Å) and three longer (3.21 Å) Ag–Sb bond lengths. In the second Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three equivalent Ag1+ and three equivalent Sb3- atoms. All Ag–Sb bond lengths are 2.84 Å. Sb3- is bonded in a 10-coordinate geometry to three equivalent Sr2+ and seven Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(CO2)2 by Materials Project

SrC2O4 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.51–2.78 Å. There are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.26 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both C–O bond lengths are 1.25 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Sr2+ and one C3+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Sr2+ and one C3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(GaS2)2 by Materials Project

SrGa2S4 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.15 Å) and four longer (3.18 Å) Sr–S bond lengths. Ga3+ is bonded to four S2- atoms to form edge-sharing GaS4 tetrahedra. There are a spread of Ga–S bond distances ranging from 2.29–2.34 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Ga3+ atoms. In the second S2- site, S2- is bonded to two equivalent Sr2+ and two equivalent Ga3+ atoms to form a mixture of distorted corner and edge-sharing SSr2Ga2 trigonal pyramids.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

SR-1 Freedom Thermal Architecture Challenges

The SR-1 Freedom mission aims to demonstrate nuclear electric propulsion (NEP) and deliver the Skyfall helicopter payload to Mars. Repurposing the existing Gateway Power and Propulsion Element (PPE) spacecraft and combining it with a 20 kWe-class nuclear power module (NPM) presents a variety of thermal architecture challenges. These include unprecedented waste heat rejection requirements, integration with a spacecraft bus originally designed for a different mission profile, and novel packaging constraints. This presentation will describe the simplified concept of operations as it relates to on-orbit thermal environments, early-phase architecture trades and supporting analyses, and planned forward work. We will also discuss our strategy for integrated thermal modeling of the complete spacecraft and examples of interface challenges necessitated by this ambitious effort.

Thermal↗