Session
Weekend Session 5: Science/Mission Payloads - Research & Academia II
Location
Utah State University, Logan, UT
Abstract
In June 2019, ESA selected Comet Interceptor as its first "F" class mission. A Dynamically New Comet (DNC) is a subset of long-period comets that originate in the Oort cloud and may hold some of the most primitive material from the early days of our Solar System. Comet Interceptor (CI) aims to be the first mission to visit a long-period comet. As part of ESA's ARIEL mission, CI is scheduled to launch at the Earth-Sun L2 point in 2028 where it will await a suitable DNC target.
The CI mission is comprised of three spacecraft. As part of the CI Spacecraft A scientific payload, the Modular InfraRed Molecular and Ices Sensor (MIRMIS) is presented in this paper. A single compact (210 x 105.5 x 460 mm³) instrument combines three integrated MIRMIS channels; MIR (0.9 to 1.7 μm), NIR (2.5 -5.0 μm), and TIRI (~6 to 25 μm). The module is connected to the spacecraft via bolted support struts. These hollow struts made of Ti-64 are glued to the optical bench and pose a special concern to the overall structural integrity.
A summary of the FEA analysis for the MIRMIS instrument is presented in this document. As per the ESA specification guidelines, five types of studies needed to be conducted. This included static structural analysis, modal analysis, random vibration analysis, sine vibration analysis, and shock response analysis. For the static structural studies, the model was subjected to quasi-static loads of 48g in all directions non-simultaneously. Bolt size was increased from M3 to M4 to avoid peak stress gradients. Mode shapes were calculated as a pre-requisite to the other linear analysis, modal analysis being the most fundamental of all dynamic analyses. It is the basis of all other linear dynamic analyses that follow. Modal analysis was carried out for the X, Y, and Z axis non simultaneously. The fundamental frequency from the first mode shape was around 300 Hz, within the acceptable range.
The objective of the random vibration analysis was to perform a dynamic analysis on the MIRMIS instrument. The objective of the sine vibration analysis was to predict the location, frequency, and phase angle of the maximum response and the corresponding stresses. The peak displacement occurs at a frequency of 55 Hz for all three axis non-simultaneous loading conditions. MIRMIS components show a good Margin of safety (MOS) for withstanding quasi-static and shock response loads. The deflections observed from the harmonic and random vibration assessments were below 2mm indicating that the structural components will not collide with one another. The peak stresses near the hollow support struts indicate that the structure will be able to endure the loading conditions for static, shock response, harmonic, and random vibration analysis.
Structural Analysis for the Modular Infrared Molecules and Ices Sensor (MIRMIS) Instrument
Utah State University, Logan, UT
In June 2019, ESA selected Comet Interceptor as its first "F" class mission. A Dynamically New Comet (DNC) is a subset of long-period comets that originate in the Oort cloud and may hold some of the most primitive material from the early days of our Solar System. Comet Interceptor (CI) aims to be the first mission to visit a long-period comet. As part of ESA's ARIEL mission, CI is scheduled to launch at the Earth-Sun L2 point in 2028 where it will await a suitable DNC target.
The CI mission is comprised of three spacecraft. As part of the CI Spacecraft A scientific payload, the Modular InfraRed Molecular and Ices Sensor (MIRMIS) is presented in this paper. A single compact (210 x 105.5 x 460 mm³) instrument combines three integrated MIRMIS channels; MIR (0.9 to 1.7 μm), NIR (2.5 -5.0 μm), and TIRI (~6 to 25 μm). The module is connected to the spacecraft via bolted support struts. These hollow struts made of Ti-64 are glued to the optical bench and pose a special concern to the overall structural integrity.
A summary of the FEA analysis for the MIRMIS instrument is presented in this document. As per the ESA specification guidelines, five types of studies needed to be conducted. This included static structural analysis, modal analysis, random vibration analysis, sine vibration analysis, and shock response analysis. For the static structural studies, the model was subjected to quasi-static loads of 48g in all directions non-simultaneously. Bolt size was increased from M3 to M4 to avoid peak stress gradients. Mode shapes were calculated as a pre-requisite to the other linear analysis, modal analysis being the most fundamental of all dynamic analyses. It is the basis of all other linear dynamic analyses that follow. Modal analysis was carried out for the X, Y, and Z axis non simultaneously. The fundamental frequency from the first mode shape was around 300 Hz, within the acceptable range.
The objective of the random vibration analysis was to perform a dynamic analysis on the MIRMIS instrument. The objective of the sine vibration analysis was to predict the location, frequency, and phase angle of the maximum response and the corresponding stresses. The peak displacement occurs at a frequency of 55 Hz for all three axis non-simultaneous loading conditions. MIRMIS components show a good Margin of safety (MOS) for withstanding quasi-static and shock response loads. The deflections observed from the harmonic and random vibration assessments were below 2mm indicating that the structural components will not collide with one another. The peak stresses near the hollow support struts indicate that the structure will be able to endure the loading conditions for static, shock response, harmonic, and random vibration analysis.
