Particle Electrostatic Studies at Kennedy Space Center...National Aeronautics and Space...
14
National Aeronautics and Space Administration John F. Kennedy Space Center SPACEPORT ENGINEERING AND TECHNOLOGY Particle Electrostatics Studies at Kennedy Space Center Carlos I. Calle NASA Electromagnetic Physics Laboratory
Transcript of Particle Electrostatic Studies at Kennedy Space Center...National Aeronautics and Space...
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Particle Electrostatics Studies at Kennedy Space Center
Carlos I. CalleNASA
Electromagnetic Physics Laboratory
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY Outline
• Research Team• Objectives• Motivation• Facilities• Research• Future Projects
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY Research Team
• Carlos Calle, Ph.D. Physics• Ray Gompf, Ph.D. E.E.• Charles Buhler, Ph.D. Physics• Mike Hogue, M.S. Physics• Andrew Nowicki, B.S. Physics• Ellen Group Physics
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY Objectives• Electrostatics studies and materials
characterization to assist in issues related to electrostatic charge generation and prevention in the shuttle, international space station, and payload work areas.
• Development, Testing, and Calibration of Electrostatic Instrumentation for Planetary Missions (JPL collaboration).
• Electrostatic characterization of Mars and Lunar simulant soils and their interaction with different materials under simulated environmental conditions.
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Effects of Dust on Mars
•Dry surface conditions and fine clays of the Martian soil are conducive to electrostatic charge buildup which may compromise performance and safety of equipment:
–Solar cell performance will degrade as dust collects on the solar panels.
–Dust that collects on viewing ports will reduce light throughput.
–Thermal radiators will become clogged by dust.
–Movement of mechanical parts will be impeded.
–Dust will adhere to space suits. ~ 0.2% power loss/sol.Ref: R. C. Ewell and D. R. Burger, “Solar Array Model Corrections from the Mars Pathfinder Lander Data”, 28th
Photovoltaic Specialists Conference, 1997.
(Po-P)/Po = 0.182·t
-4
-2
0
2
4
6
8
10
12
14
16
0 20 40 60 80
TIME, t (Sol)
PO
WE
R L
OS
S, (
Po
-P)/
Po
(%)
Dust9b11.xls
Pathfinder Solar Cell Degradation
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY Effects of Dust on the Moon
• Apollo and Clementinedata indicate that electrostatic phenomena can take place on the Moon:– A horizon glow 1 m
above surface was detected
– Apollo 17 detected dust transport on surface
•Dust adhering to surfaces is a major problem for future Lunar missions•Equipment in Apollo missions was rendered unusable after 3 days of exposure to dust
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Facilities and Equipment
Multisensor ElectrometerMars Electrostatics Chamber
Dust Impeller Environmental Chamber
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Current Projects
• Rock and Roll Experiments• Corona Charging• Rubbing Machine• Dust Impeller
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY Rock and Roll Experiments
• Sand charges but does not coat the insulators.
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0
0.05
0.10
0.15
0.20
0.25
0 50 100 150TIME, t (sec)
AM
PL
IFIE
R O
UT
PU
T, V
A (V
)
TRI1TRI2TRI3TRI4TRI5
T(°C)=26.0ELE810011527 16-Jan-00
OTTAWA SAND HEMATITE
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0 50 100 150TIME, t (sec)
AM
PL
IFIE
R O
UT
PU
T, V
A (V
)
TRI1TRI2TRI3TRI4TRI5
T(°C)=27.2ELE810011546 16-Jan-00
• Hematite charges and coats the insulators
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Rock and Roll Experiments
CO2 at 10 mbar. The amount of charge generated on the five insulators is proportional to the output voltage. The first few data points are taken prior to rocking the Martian soil simulant over the sensors. Time interval between data sampling is 1.1 sec.
Charging of Insulator Surfaces by Rocking Martian Soil Simulant over the Samples at 10 mbar CO2 Pressure. File: ELE 2000-6-29 88-Run 33
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.0 10.9 21.9 32.8 43.7
Time (sec)
Tri
bo
Sen
sor
Ou
tpu
t (v
olt
s)
Fiberglass Lexan Teflon Rulon J Lucite
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Corona Charging of Dust
Decay rate after corona charging of lunarsimulant soil at 1% RH (atmospheric pressure).
Charge Decay for Lunar Soil Simulant
-800
-700
-600
-500
-400
-300
-200
-100
00 20 40 60 80 100 120 140
Time (s)
Vo
ltag
e (V
)
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Rubbing Experiments
Top left: Rubbing polymers with 5-µm Martian simulant dust particles at room temperature.
Top right: T= -100 ºC
Bottom right; T= -118 ºC
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY
Dust Impeller
• Electrostatic charge developed on polymers impacted by 5-µm Martian simulant dust particles at 20 m/s in a CO2 atmosphere at 10 mbars.
National Aeronautics andSpace Administration
John F. Kennedy Space Center
SPACEPORT ENGINEERING AND TECHNOLOGY Opportunities for Collaboration
• Particle behavior under different environmental conditions– Electrostatic interactions with surfaces– Dynamic inter-particle and particle-surface
electrostatic interactions• Funding
– NRAs: Currently ROSS-2001: PIDDP (Planetary Instrument Definition and Development Program)
– NSF: Basic granular material science
