Kaushik Iyer Print


  240-228-8936

  Kaushik.Iyer@jhuapl.edu

: SES

:   Materials Physicist

:  Earth, Planetary

  Europa Clipper, New Horizons, Parker Solar Probe

 
Degree Field of Study Year Attained Institution Name
Ph.D. Materials Science & Engineering 1997 Vanderbilt University

Iyer's expertise is in the area of Space Environment Hypervelocity Impact Hazard Mitigation. He has also collaborated with planetary scientists to tailor material models for simulating planetary features resulting from HVI.

Interplanetary dust particle (IDP) and space debris hazard mitigation is a recurring concern to critical spacecraft mission ops and science payloads.  NASA’s Mars Reconnaissance Orbiter, Cassini to Saturn and its moons, Juno to Jupiter and New Horizons to Pluto are some recent and ongoing missions that have had to evaluate the hazards of micron-to-millimeter scale porous cometary and asteroidal particles consisting of dense rocky and iron aggregates traveling at tens to hundreds of kilometers per second relative to exposed spacecraft components.  At such speeds, even dust sized particles have the potential to destroy or disrupt cooling systems, power systems, electrical systems and instruments.  Naturally, these risks are more severe for longer missions and dustier orbits.  Earth-orbiting satellites and the ISS face similar hazards from manmade orbital debris (OD) also.  The science of evaluating the risks to missions associated with these hazards, specific system failure and damage modes, and providing mitigating design specifications to vulnerable systems involves a unique multi-disciplinary capability that spans expertise in spacecraft systems engineering, mission operations, planetary science, hypervelocity impact (HVI) shock physics, materials science and mechanical engineering.

For evaluating spacecraft/satellite damage and failure modes, the space systems HVI hazard mitigation community currently uses extrapolation of HVI data generated at ground testing speeds (2-10 km/s) out to higher, realistic impact speeds such as 30 km/s; even though the material response mechanism changes from mechanical failure to thermal phase change and dissociations after about 9 km/s.  As concern over the possibility of unacceptable damage to spacecraft/satellite components from dust impacts has grown, engineers have come to rely on multi-layer insulation (MLI) blankets not only for thermal control but also for protection against dust.  Application of the current extrapolation methodology developed for metal monolithic shields has proliferated to blankets and other non-monolithic structures also.  Extrapolation is generally hoped to provide high levels of protection with margin (conservatism), but this is not verified in any way despite changes in structure and material response at higher impact speeds. 

Dust hazard mitigation work at the Space Exploration Sector (SES) of The Johns Hopkins University Applied Physics Laboratory (JHU/APL) over the past 6 years has led to a systematic reduction in the need to rely on extrapolations for materials/systems damage assessments.  This work, for the Solar Probe Plus (SPP) and other missions, was necessitated by unprecedented exposure to dust impacts at speeds as high as 300 km/s and extensive reliance on blankets for protection.  The APL methodology integrates ground-based HVI testing and failure analysis for validation, and rigorously tested and verified shock physics-based hydrocode computations for shielding design.  It is not only data- and physics-based but also quantifies safety margins.  The physics-based methodology shows that the current extrapolation methodology for predicting the protective capability of blankets is in fact non-conservative up to about 45 km/s.  The methodology is also amenable to treating advanced non-metallics and complex materials considered for shielding such as MLI and honeycomb structures, as well as systems such as solar arrays, which are beyond the capability of the existing approach.

 
AGU Index Category AGU Index Sub-Category
INTERPLANETARY PHYSICS Interplanetary dust
ELECTROMAGNETICS General or miscellaneous
:
Start Year End Year Description
2010 Current Principal Professional Staff, Section Supervisor, Project Manager, Johns Hopkins University Applied Physics Laboratory
No items
Year Description
2015 Outstanding Development Paper in an Externally Referred Publication: Interplanetary Dust Particle Shielding Capability of Spacecraft Multi-Layer Insulation
2013 R. W. Hart Prize for Best IR&D Research Project
:
The following publication information was downloaded from http://www.researcherId.com/rid/H-1411-2016.
Whelchel, R. L., Mehoke, D. S., Iyer, K. A., Sanders, T. H., Jr., Thadhani, N. N., (2016), Dynamic yielding and fracture of grade 4 titanium in plate impact experiments, Journal of Applied Physics, 119

Chadegani, Alireza, Iyer, Kaushik A., Mehoke, Douglas S., Batra, Romesh C., (2015), Hypervelocity impact of a steel microsphere on fused silica sheets, International Journal of Impact Engineering, 80, 116-132

Iyer, Kaushik A., Mehoke, Douglas S., Batra, Romesh C., (2015), Interplanetary Dust Particle Shielding Capability of Spacecraft Multilayer Insulation, Journal of Spacecraft and Rockets, 52, 584-594

Buczkowski, D. L., Wyrick, D. Y., Iyer, K. A., Kahn, E. G., Scully, J. E. C., Nathues, A., Gaskell, R. W., Roatsch, T., Preusker, F., Schenk, P. M., Le Corre, L., Reddy, V., Yingst, R. A., Mest, S., Williams, D. A., Garry, W. B., Barnouin, O. S., Jaumann, R., Raymond, C. A., Russell, C. T., (2012), Large-scale troughs on Vesta: A signature of planetary tectonics, Geophysical Research Letters, 39

Mehoke, Douglas S., Swaminathan, P. K., Carrasco, Cesar J., Brown, Robert C., Kerley, Gerald I., Iyer, Kaushik A., IEEE, (2012), A Review of the Solar Probe Plus Dust Protection Approach, 2012 Ieee Aerospace Conference

Iyer, Kaushik A., (2007), Relationships between multiaxial stress states and internal fracture patterns in sphere-impacted silicon carbide, International Journal of Fracture, 146, 1-18

Iyer, K, (2005), Analysis of the size effect in partial-slip contact fatigue, Journal of Tribology-Transactions of the Asme, 127, 443-446

Iyer, K, Hu, SJ, Brittman, FL, Wang, PC, Hayden, DB, Marin, SP, (2005), Fatigue of single- and double-rivet self-piercing riveted lap joints, Fatigue & Fracture of Engineering Materials & Structures, 28, 997-1007

Lin, G, Iyer, K, Hu, SJ, Cai, W, Marin, SP, (2005), A computational design-of-experiments study of hemming processes for automotive aluminium alloys, Proceedings of the Institution of Mechanical Engineers Part B-Journal of Engineering Manufacture, 219, 711-722

Chin, M, Iyer, KA, Hu, SJ, (2004), Prediction of electrical contact resistance for anisotropic conductive adhesive assemblies, Ieee Transactions on Components and Packaging Technologies, 27, 317-326

Iyer, K, (2001), Peak contact pressure, cyclic stress amplitudes, contact semi-width and slip amplitude: relative effects on fretting fatigue life, International Journal of Fatigue, 23, 193-206

Iyer, K, (2001), Solutions for contact in pinned connections, International Journal of Solids and Structures, 38, 9133-9148

Iyer, K, Mall, S, (2001), Analyses of contact pressure and stress amplitude effects on fretting fatigue life, Journal of Engineering Materials and Technology-Transactions of the Asme, 123, 85-93

Iyer, K, Rubin, CA, Hahn, GT, (2001), Influence of interference and clamping on fretting fatigue in single rivet-row lap joints, Journal of Tribology-Transactions of the Asme, 123, 686-698

Iyer, K, Mall, S, (2000), Effects of cyclic frequency and contact pressure on fretting fatigue under two-level block loading, Fatigue & Fracture of Engineering Materials & Structures, 23, 335-346

Iyer, K, Bastias, PC, Rubin, CA, Hahn, GT, Cook, R, Poole, P, (1997), Analysis of fatigue and fretting of three-dimensional, single and double rivet-row lap joints, Icaf 97: Fatigue in New and Ageing Aircraft, Vols I and Ii, 855-869

IYER, K, HAHN, GT, BASTIAS, PC, RUBIN, CA, (1995), ANALYSIS OF FRETTING CONDITIONS IN PINNED CONNECTIONS, Wear, 181, 524-530