Jarvis Songer - Academia.edu (original) (raw)

Papers by Jarvis Songer

Introduction: The InSight Mars Lander successfully landed on the surface on November 26, 2018. Th... more Introduction: The InSight Mars Lander successfully landed on the surface on November 26, 2018. This poster will describe the methodologies and margins used in developing the aerothermal environments for design of the thermal protection systems (TPS), as well as a prediction of as-flown environments based on the best estimated trajectory. The InSight mission spacecraft design approach included the effects of radiant heat flux to the aft body from the wake for the first time on a US Mars Mission, due to overwhelming evidence in ground testing for the European ExoMars mission (2009/2010) [1] and 2010 tests in the Electric Arc Shock Tube (EAST) facility [2]. The radiant energy on an aftbody was also recently confirmed via measurement on the Schiaparelli mission [3]. In addition, the InSight mission expected to enter the Mars atmosphere during the dust storm season, so the heatshield TPS was designed to accommodate the extra recession due to the potential dust impact. This poster will co...

Journal of Spacecraft and Rockets, 2021

The Mars Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) ... more The Mars Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft, which successfully touched down on the planet surface on November 26, 2018, was proposed...

Acta Astronautica, 2019

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OS... more The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft launched on September 8, 2016, beginning a seven-year journey to return at least 60 g of asteroid material from (101955) Bennu to Earth. During the outbound cruise, Doppler tracking of the spacecraft observed a small but measurable acceleration when the sample return capsule (SRC) was first placed in sunlight. Subsequent analysis determined that outgassing from the SRC is the most likely cause for the acceleration. This outgassing received combined engineering and scientific attention because it has potential implications both for spacecraft navigation performance and for contamination of the collected samples. Thermal modeling, laboratory studies of SRC materials, and monitoring of the acceleration are all consistent with H 2 O as the main component of the outgassing. Dedicated, in-flight campaigns continued to expose the SRC to sunlight until the acceleration dropped to the acceleration noise floor. Any residual amounts of H 2 O outgassing are not considered to be a hazard with regards to mission operations or pristine sample acquisition. The sample stow procedure has been updated to ensure that no direct line of site exists between any residual outgassing and the samples during future operations. Similar outgassing of the Stardust SRC probably also occurred. No adverse contamination of Stardust samples was observed that could be associated with this process. Future missions that use similar reentry vehicles should consider procedures to test for and, if necessary, mediate such outgassing after launch.

19th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, 2007

... Aerocapture Inflatable Decelerator ( AID ) for Planetary Entry. by Sajjad Reza, Richard Hund,... more ... Aerocapture Inflatable Decelerator ( AID ) for Planetary Entry. by Sajjad Reza, Richard Hund, Frank Kustas, William Willcockson ... in Distribution (2007). 1 reader Save reference to library · Related research. Aero-Structural Assessment of an Inflatable Aerodynamic Decelerator. ...

41st AIAA Thermophysics Conference, 2009

Thermal protection system materials for the Mars Science Laboratory mission were tested in the NA... more Thermal protection system materials for the Mars Science Laboratory mission were tested in the NASA Ames 60 MW arcjet in a shear environment. Shear tests were performed on candidate ablative heat shield materials in wedge and swept cylinder test fixtures. In portions of the expected flight environment, the proposed main heat shield material, known as SLA-561V, recessed orders of magnitude faster than predicted. An alternate main heat shield material, known as phenolic impregnated carbon ablator, behaved reasonably well in all regions of the flight envelope investigated here. However, the measured recession rate of the phenolic impregnated carbon ablator was on average 50% greater than the predicted recession by the fully implicit ablation and thermal response code, and in some cases the measured recession was as much as 150% greater (uncertainties included). Phenolic impregnated carbon ablator's higher recession rate than predicted (in shear) resulted in adding thickness margin to the flight heat shield design. Other tests of the phenolic impregnated carbon ablator heat shield system, including tests of various gap fillers, damage scenarios, and repair scenarios, demonstrated the robustness of this heat shield system for use in the predicted Mars Science Laboratory flight environment.

Journal of Spacecraft and Rockets, 2011

[Abstract] Aerothermal analyses of the Phoenix entry vehicle in the Martian Atmosphere are presen... more [Abstract] Aerothermal analyses of the Phoenix entry vehicle in the Martian Atmosphere are presented. Two Navier-Stokes flow solvers are used to predict the environments experienced by the vehicle along several design trajectories. The majority of the solutions are computed as axisymmetric in order to yield higher, and therefore more conservative, heating rates. Several three-dimensional cases are also computed to assess the heating enhancement caused by surface singularities and the complex aftbody vortices. When the thermal protection system was assessed in a separate analysis in response to the computed aeroheating environments, the prebuilt design is found perform successfully.

Introduction: The InSight Mars Lander successfully landed on the surface on November 26, 2018. Th... more Introduction: The InSight Mars Lander successfully landed on the surface on November 26, 2018. This poster will describe the methodologies and margins used in developing the aerothermal environments for design of the thermal protection systems (TPS), as well as a prediction of as-flown environments based on the best estimated trajectory. The InSight mission spacecraft design approach included the effects of radiant heat flux to the aft body from the wake for the first time on a US Mars Mission, due to overwhelming evidence in ground testing for the European ExoMars mission (2009/2010) [1] and 2010 tests in the Electric Arc Shock Tube (EAST) facility [2]. The radiant energy on an aftbody was also recently confirmed via measurement on the Schiaparelli mission [3]. In addition, the InSight mission expected to enter the Mars atmosphere during the dust storm season, so the heatshield TPS was designed to accommodate the extra recession due to the potential dust impact. This poster will co...

Journal of Spacecraft and Rockets, 2021

The Mars Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) ... more The Mars Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft, which successfully touched down on the planet surface on November 26, 2018, was proposed...

Acta Astronautica, 2019

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OS... more The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft launched on September 8, 2016, beginning a seven-year journey to return at least 60 g of asteroid material from (101955) Bennu to Earth. During the outbound cruise, Doppler tracking of the spacecraft observed a small but measurable acceleration when the sample return capsule (SRC) was first placed in sunlight. Subsequent analysis determined that outgassing from the SRC is the most likely cause for the acceleration. This outgassing received combined engineering and scientific attention because it has potential implications both for spacecraft navigation performance and for contamination of the collected samples. Thermal modeling, laboratory studies of SRC materials, and monitoring of the acceleration are all consistent with H 2 O as the main component of the outgassing. Dedicated, in-flight campaigns continued to expose the SRC to sunlight until the acceleration dropped to the acceleration noise floor. Any residual amounts of H 2 O outgassing are not considered to be a hazard with regards to mission operations or pristine sample acquisition. The sample stow procedure has been updated to ensure that no direct line of site exists between any residual outgassing and the samples during future operations. Similar outgassing of the Stardust SRC probably also occurred. No adverse contamination of Stardust samples was observed that could be associated with this process. Future missions that use similar reentry vehicles should consider procedures to test for and, if necessary, mediate such outgassing after launch.

19th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, 2007

... Aerocapture Inflatable Decelerator ( AID ) for Planetary Entry. by Sajjad Reza, Richard Hund,... more ... Aerocapture Inflatable Decelerator ( AID ) for Planetary Entry. by Sajjad Reza, Richard Hund, Frank Kustas, William Willcockson ... in Distribution (2007). 1 reader Save reference to library · Related research. Aero-Structural Assessment of an Inflatable Aerodynamic Decelerator. ...

41st AIAA Thermophysics Conference, 2009

Thermal protection system materials for the Mars Science Laboratory mission were tested in the NA... more Thermal protection system materials for the Mars Science Laboratory mission were tested in the NASA Ames 60 MW arcjet in a shear environment. Shear tests were performed on candidate ablative heat shield materials in wedge and swept cylinder test fixtures. In portions of the expected flight environment, the proposed main heat shield material, known as SLA-561V, recessed orders of magnitude faster than predicted. An alternate main heat shield material, known as phenolic impregnated carbon ablator, behaved reasonably well in all regions of the flight envelope investigated here. However, the measured recession rate of the phenolic impregnated carbon ablator was on average 50% greater than the predicted recession by the fully implicit ablation and thermal response code, and in some cases the measured recession was as much as 150% greater (uncertainties included). Phenolic impregnated carbon ablator's higher recession rate than predicted (in shear) resulted in adding thickness margin to the flight heat shield design. Other tests of the phenolic impregnated carbon ablator heat shield system, including tests of various gap fillers, damage scenarios, and repair scenarios, demonstrated the robustness of this heat shield system for use in the predicted Mars Science Laboratory flight environment.

Journal of Spacecraft and Rockets, 2011

[Abstract] Aerothermal analyses of the Phoenix entry vehicle in the Martian Atmosphere are presen... more [Abstract] Aerothermal analyses of the Phoenix entry vehicle in the Martian Atmosphere are presented. Two Navier-Stokes flow solvers are used to predict the environments experienced by the vehicle along several design trajectories. The majority of the solutions are computed as axisymmetric in order to yield higher, and therefore more conservative, heating rates. Several three-dimensional cases are also computed to assess the heating enhancement caused by surface singularities and the complex aftbody vortices. When the thermal protection system was assessed in a separate analysis in response to the computed aeroheating environments, the prebuilt design is found perform successfully.