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RbAu is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Rb1+ is bonded in a body-centered cubic geometry to eight equivalent Au1- atoms. All Rb–Au bond lengths are 3.64 Å. Au1- is bonded in a body-centered cubic geometry to eight equivalent Rb1+ atoms.
RbAu(SO4)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Rb1+ is bonded to twelve O2- atoms to form RbO12 cuboctahedra that share corners with four equivalent SO4 tetrahedra, edges with four equivalent RbO12 cuboctahedra, edges with four equivalent SO4 tetrahedra, and faces with two equivalent RbO12 cuboctahedra. There are a spread of Rb–O bond distances ranging from 3.10–3.36 Å. Au3+ is bonded in a square co-planar geometry to four O2- atoms. All Au–O bond lengths are 2.04 Å. S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with two equivalent RbO12 cuboctahedra and edges with two equivalent RbO12 cuboctahedra. There are a spread of S–O bond distances ranging from 1.45–1.56 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to two equivalent Rb1+ and one S6+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three equivalent Rb1+ and one S6+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Au3+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Au3+, and one S6+ atom.
RbAu(SeO4)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Rb1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Rb–O bond distances ranging from 2.95–3.41 Å. Au5+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Au–O bond lengths are 2.03 Å. Se5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.64 Å) and two longer (1.75 Å) Se–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Rb1+ and one Se5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Rb1+ and one Se5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Rb1+, one Au5+, and one Se5+ atom.
In early 2004, JPL successfully landed two Rovers, named Spirit and Opportunity, on the surface of Mars after traveling > 300 million miles over a 6-7 month period. In order to operate for extended duration (>9 months), both Rovers are equipped with rechargeable Lithium-ion batteries, which have enabled operation for over 854 and 834 Sols of operation, respectively, to date. Given that the batteries were required to support the mission for 90 Sols of operation by design, it is significant that the batteries have demonstrated over a nine fold increase in life over mission objectives. In addition to supporting the surface operations in conjunction with a triple-junction deployable solar arrays, the batteries were designed to aid in the launch and the EDL pyros, and allow for anomalies during cruise. In summary, the requirements of the Lithium-ion battery include the ability to provide power at least 90 sols on the surface of Mars, operate over a wide temperature range (-20 C to +30 C), withstand long storage periods (e.g., cruise period), operate in an inverted orientation, and support high current pulses (e.g., firing pyro events). In order to determine the viability of meeting these requirements, ground testing was performed on a Rover Battery Assembly Unit (RBAU), consisting of two 8-cell 10 Ah lithium-ion batteries connected in parallel. The RBAU upon which the performance testing was performed is nearly identical to the batteries incorporated into the two Rovers currently on Mars. The testing includes, (a) performing initial characterization tests (discharge capacity at different temperatures), (b) simulating the launch conditions, (c) simulating the cruise phase conditions (including trajectory correction maneuvers), (d) simulating the entry, decent, and landing (EDL) pulse load profile (required to support the pyros) (e) simulating the Mars surface operation mission simulation conditions, as well as, (f) assessing capacity loss and impedance characteristics as a function of temperature and life. This paper provides further detail to previously reported results1 of the RBAU testing program, especially with regard to the life characteristics. To date, the lithium-ion batteries (fabricated by Lithion/Yardney, Inc.) have been demonstrated to far exceed the requirements defined by the mission, both on Mars and on the ground, and are projected to support an extended mission (> 4 years).
In early 2004, JPL successfully landed two Rovers, named Spirit and Opportunity, on the surface of Mars after traveling > 300 million miles over a 6-7 month period. In order to operate for extended duration on the surface of Mars, both Rovers are equipped with rechargeable Lithium-ion batteries, which were designed to aid in the launch, correct anomalies during cruise, and support surface operations in conjunction with a triple-junction deployable solar arrays. The requirements of the Lithium-ion battery include the ability to provide power at least 90 sols on the surface of Mars, operate over a wide temperature range (-20(deg)C to +4O(deg)C), withstand long storage periods (e.g., cruise period), operate in an inverted position, and support high currents (e.g., firing pyro events). In order to determine the viability of meeting these requirements, ground testing was performed on a Rover Battery Assembly Unit (RBAU), consisting of two 8-cell 8 Ah lithium-ion batteries connected in parallel. The RBAU upon which the performance testing was performed is nearly identical to the batteries incorporated into the two Rovers currently on Mars. The testing performed includes, (a) performing initial characterization tests (discharge capacity at different temperatures), (b) simulating the launch conditions, (c) simulating the cruise phase conditions (including trajectory corrections), (d) simulating the entry, decent, and landing pulse load profile (if required to support the pyros) (e) simulating the Mars surface operation mission simulation conditions, as well as, (f) assessing performance capacity loss and impedance characteristics as a function of temperature and life. As will be discussed, the lithium-ion batteries (fabricated by LithiodYardney, Inc.) were demonstrated to far exceed the requirements defined by the mission, and are projected to support an extended mission (> 2 years) with margin to spare.
In early 2004, JPL successfully landed two Rovers, named Spirit and Opportunity, on the surface of Mars after traveling > 300 million miles over a 6-7 month period. In order to operate for extended duration on the surface of Mars, both Rovers are equipped with rechargeable Lithium-ion batteries, which were designed to aid in the launch, correct anomalies during cruise, and support surface operations in conjunction with a triple-junction deployable solar arrays. The requirements of the Lithium-ion battery include the ability to provide power at least 90 sols on the surface of Mars, operate over a wide temperature range (-20(super 0)C to +40(super 0)C), withstand long storage periods (e.g., including pre-launch and cruise period), operate in an inverted position, and support high currents (e.g., firing pyro events). In order to determine the inability of meeting these requirements, ground testing was performed on a Rover Battery Assembly Unit RBAU), consisting of two 8-cell 8 Ah lithium-ion batteries connected in parallel. The RBAU upon which the performance testing was performed is nearly identical to the batteries incorporated into the two Rovers currently on Mars. The primary focus of this paper is to communicate the latest results regarding Mars surface operation mission simulation testing, as well as, the corresponding performance capacity loss and impedance characteristics as a function of temperature and life. As will be discussed, the lithium-ion batteries (fabricated by Yardney Technical Products, Inc.) have been demonstrated to far exceed the requirements defined by the mission, being able to support the operation of the rovers for over three years, and are projected to support an even further extended mission.