Impact of the Microgravity Environment on Experiments The Effect of G-Jitter on Fluid Science Experiments
Bjarni Tryggvason Canadian Space Agency
Glenn Research Center March 6-8, 2001 Impact of the Microgravity Environment on Experiments
The Microgravity Vibration Isolation Mount (MIM-2)
Isolates experiments from spacecraft vibrations
6 DOF magnetically levitation system
Optical tracking system and accelerometers for monitoring and control
Provides data acquisition services and control functions to an experiment mounted on the flotor
Capable of “shaking” an experiment with acceleration levels from several micro-g to 25 milli-g over range 0.01 Hz to 50 Hz.
March 7, 2001 MEIT-2001 / Section 13 / Page 2 Impact of the Microgravity Environment on Experiments MIM-1 Fluid Physics Experiment on the Mir Space Station
Supported numerous experiments that examined effects of g-jitter on fluids
● QUELD-II ● Liquid Metal Diffusion (LMD) ● TEM, TEM-2 ● Canadian Protein Crystallization Experiment (CAPE)
Queen’s University Experiment in Liquid Diffusion
● Operational on Mir Space Station from May 1996 to January 1998 ● Operating temperature up to 900 °C ● Two independent furnaces ● Automatic sample processing March 7, 2001 MEIT-2001 / Section 13 / Page 3 Impact of the Microgravity Environment on Experiments MIM- 2 on Shuttle Mission STS-85
March 7, 2001 MEIT-2001 / Section 13 / Page 4 Impact of the Microgravity Environment on Experiments Summary of the Experiments
ISS Phase-I on Mir:
• measurement of diffusion in liquid metal systems
• observations of nucleation in glasses
• particle pushing
STS-85:
• effect of g-jitter on Brownian motion
• effect of g-jitter on the motion of encapsulated bubbles
• effect of g-jitter on interface dynamics in a liquid-liquid system
• effects of g-jitter on interface dynamics in liquid-vapour systems
March 7, 2001 MEIT-2001 / Section 13 / Page 5 Impact of the Microgravity Environment on Experiments Liquid Diffusion Coefficient
The contributions to the measured diffusion coefficient can be attributed to:
D + D + D intrinsic buoyancy container D = (1) Measured +D + D thermal Marangoni
Estimating the Intrinsic Diffusion Coefficient • Microgravity eliminates buoyancy effects. • The effect of the container is estimated by varying the sample diameter. • A well designed sample eliminates surface tension induced Marangoni convection by the use of a spring to adjust for specimen contraction and expansion. • An isothermal furnace eliminates thermal gradient induced motion.
March 7, 2001 MEIT-2001 / Section 13 / Page 6 Impact of the Microgravity Environment on Experiments Comparison of Terrestrial and On-Orbit Data
CdIn / CdSn diffusion couple specimens processed terrestrially and in microgravity at 690 C for 90 minutes [Tandon, Cahoon and Chaturvedi. CSA Interim Report] .
March 7, 2001 MEIT-2001 / Section 13 / Page 7 Impact of the Microgravity Environment on Experiments
At%
Displacement Terrestrial liquid-metal diffusion measurements of a CdIn/CdSn diffusion couple specimen at 690 C for 90 minutes [Tandon, Cahoon and Chaturvedi. CSA Interim Report] . March 7, 2001 MEIT-2001 / Section 13 / Page 8 Impact of the Microgravity Environment on Experiments
At%
Displacement Microgravity liquid-metal diffusion measurements of a CdIn/CdSn diffusion couple specimen at 690 C for 90 minutes [Tandon, Cahoon and Chaturvedi. CSA Interim Report].
March 7, 2001 MEIT-2001 / Section 13 / Page 9 Impact of the Microgravity Environment on Experiments Temperature Dependence of Diffusion
• There are many competing models for the temperature dependence of diffusion.
• The fluctuation model, supported by previous microgravity experiments, proposes that the diffusion coefficient should be proportional to the temperature squared, i.e., D = AT`2
• Another model predicts a linear relationship between the diffusion coefficients and temperature, given simply as,
D = −a + bT • The difference between the two models is quite severe, especially at the higher temperatures.
March 7, 2001 MEIT-2001 / Section 13 / Page 10 Impact of the Microgravity Environment on Experiments
‡ • QUELD I & II MIM not isolating • • • • • QUELD II MIM isolating
QUELD Ground-based studies Pb self diffusion - not isolated (1 mm dia. specimens) (Frohberg et. al.) • QUELD I & QUESTS (MIM not isolating) ‡ QUELD II forced 0.1 Hz, 0.004g QUELD II isolated by MIM QUELD II (MIM not isolating) (1.5 mm and 3 mm dia. specimens for µg ) March 7, 2001 MEIT-2001 / Section 13 / Page 11 Impact of the Microgravity Environment on Experiments
Pb-Ag System 12 11 10 9
-3 8 7 Q U ELD -II isolated 1.5mm
/s) 10 6 2 5 D α T 2
(mm 4 3
Diffusion Coefficient 2 1 0 300400500600700800900
Temperature (oC) Microgravity Diffusion Coefficients of Silver in Lead showing the difference between a linear and a parabolic fit to the data (Smith et. Al.).
March 7, 2001 MEIT-2001 / Section 13 / Page 12 Impact of the Microgravity Environment on Experiments
Sb-In System 9
8
-3 7
/s) 10 QU ELD -II isolated 2 2.0mm 6 (mm
Diffusion Coefficient Coefficient Diffusion 5
4 650 750 850 o Temperature ( C) Diffusion Coefficients of Indium in Antimony (Smith et. Al.).
March 7, 2001 MEIT-2001 / Section 13 / Page 13 Impact of the Microgravity Environment on Experiments
In-Sb System 10
9
8
-3 7
/s) 10 6 QU ELD -II isolated 2 2.0mm 5 (mm
4 Diffusion Coefficient Diffusion
3
2 200 300 400 500 600 700 800 Temperature (o C) Diffusion Coefficients of Indium in Antimony (Smith et. Al.).
March 7, 2001 MEIT-2001 / Section 13 / Page 14 Impact of the Microgravity Environment on Experiments Processing of Infra-Red Glass in Microgravity
Material Nb2Na2B2O9 (NNB) ● Experimental processing conditions ● Temperature 575 o C ● Time 1 hour
● container SiO2 ● g-jitter varied from isolation to g-pulses ● g-pulses at 1000 µg at 0.1 Hz
March 7, 2001 MEIT-2001 / Section 13 / Page 15 Impact of the Microgravity Environment on Experiments
NNB Glass processed in microgravity at 575 K with isolation, showing (upper) a crystal phase only around the edge of specimen (enlarged center) but not in the specimen center (lower image).
March 7, 2001 MEIT-2001 / Section 13 / Page 16 Impact of the Microgravity Environment on Experiments
NNB glass processed in microgravity having force g-pulses at 1 mg at 0.1 Hz, showing mixing or streaming of crystal phase from edge to center of specimen.
March 7, 2001 MEIT-2001 / Section 13 / Page 17 Impact of the Microgravity Environment on Experiments Brownian Motion
Experiment Objectives
Examine the effect of g-jitter on the motion of small particles in fluids, under condition of:
• Non-isolating mode, i.e., g-jitter present
• Isolated mode
• Driven mode • Sinusoidal • Random broad band
March 7, 2001 MEIT-2001 / Section 13 / Page 18 Impact of the Microgravity Environment on Experiments
March 7, 2001 MEIT-2001 / Section 13 / Page 19 Impact of the Microgravity Environment on Experiments
March 7, 2001 MEIT-2001 / Section 13 / Page 20 Impact of the Microgravity Environment on Experiments
March 7, 2001 MEIT-2001 / Section 13 / Page 21 Impact of the Microgravity Environment on Experiments
March 7, 2001 MEIT-2001 / Section 13 / Page 22 Impact of the Microgravity Environment on Experiments Brownian Motion Discussion
The results of diffusion work carried out on the shuttle and the Mir, the Brownian Motion experiments conducted on the shuttle show a consistent sensitivity to g-jitter.
The sensitivity is in the frequency range 2 Hz to 100 Hz. The vibration levels that effect the diffusion are generally below the current ISS vibratory specification
March 7, 2001 MEIT-2001 / Section 13 / Page 23 Impact of the Microgravity Environment on Experiments Effect of G-Jitter on the Motion of an Encapsulated Bubble
The motion of a bubble several mm in diameter was recorded on video
The motion was compared for cases with and without isolation
March 7, 2001 MEIT-2001 / Section 13 / Page 24 Impact of the Microgravity Environment on Experiments
March 7, 2001 MEIT-2001 / Section 13 / Page 25 Impact of the Microgravity Environment on Experiments In summary
● Use of the MIM enabled examining the sensitivity to g-jitter ● The diffusion experiments show sensitivity to g-jitters: ● intrinsic diffusion coefficient by 2-3 times lower for isolated case vs. non-isolated case ● clear indication that diffusion is linear with temperature for the isolated case ● The fluid science results from STS-85 show significant fluid motion due to g-jitters.
March 7, 2001 MEIT-2001 / Section 13 / Page 26 Impact of the Microgravity Environment on Experiments The Vibration Environment of the Mir and the Shuttle
Over 3000 hours of acceleration data was obtained during the Mir based experiments
About 100 hours of data was obtained during the shuttle experiments
The characteristics of the vibration levels are summarized in the following figures
March 7, 2001 MEIT-2001 / Section 13 / Page 27 Impact of the Microgravity Environment on Experiments Space Station Vibratory Requirement for Isolated Payloads
The following figure summarizes:
• the vibration limits for an isolated rack on ISS
• the predicted vibration levels for the ISS
March 7, 2001 MEIT-2001 / Section 13 / Page 28 Impact of the Microgravity Environment on Experiments
Graph obtained from NASA web site http://www.lerc.nasa.govW WW/MMAP/PIMS/MEIT/ meit99pdfs.html
March 7, 2001 MEIT-2001 / Section 13 / Page 29 Impact of the Microgravity Environment on Experiments
1 10 4
1 10 3
100
10
1 RMSAccele ration(micro-g per third octave band) 0.1 1 10 3 0.01 0.1 1 10 100 1 10 3 1 10 4 Frequency (Hertz) Data obtained from Microgravity Control Plan: International Space Station Program, NASA document SSP50036, Revision A
March 7, 2001 MEIT-2001 / Section 13 / Page 30 Impact of the Microgravity Environment on Experiments Acceleration levels on the Space Shuttle
Typical Acceleration Levels on the Shuttle
March 7, 2001 MEIT-2001 / Section 13 / Page 31 Impact of the Microgravity Environment on Experiments Acceleration levels on the Space Shuttle
March 7, 2001 MEIT-2001 / Section 13 / Page 32 Impact of the Microgravity Environment on Experiments Acceleration levels on the Space Shuttle
March 7, 2001 MEIT-2001 / Section 13 / Page 33 Impact of the Microgravity Environment on Experiments Acceleration levels on the Space Shuttle
March 7, 2001 MEIT-2001 / Section 13 / Page 34 Impact of the Microgravity Environment on Experiments Cumulative Acceleration Levels on the Space Shuttle
March 7, 2001 MEIT-2001 / Section 13 / Page 35 Impact of the Microgravity Environment on Experiments Cumulative Acceleration Levels on the Space Shuttle
March 7, 2001 MEIT-2001 / Section 13 / Page 36 Impact of the Microgravity Environment on Experiments Cumulative Acceleration Levels on the Space Shuttle
March 7, 2001 MEIT-2001 / Section 13 / Page 37 Impact of the Microgravity Environment on Experiments Format for Presentation of Time Histories for Accelerations
On the time traces four lines are plotted on each figure. These are the following statistics:
• Maximum acceleration sampled over a one second interval
• Minimum acceleration sampled over a one second interval
• Standard deviation of the acceleration over the one second interval
• The mean acceleration over the one second interval, with the mean for the whole record removed
March 7, 2001 MEIT-2001 / Section 13 / Page 38 Impact of the Microgravity Environment on Experiments Acceleration on the Space Shuttle
Stator X Acceleration vs time 10
5
0 Acceleration (mg)
5
10 0 10 20 30 40 50 60 70 80 90
Max Time (sec) RMS Mean Min March 7, 2001 MEIT-2001 / Section 13 / Page 39 Impact of the Microgravity Environment on Experiments Acceleration on the Space Shuttle
Stator Z Acceleration vs time 10
5
0 Acceleration (mg)
5
10 0 10 20 30 40 50 60 70 80 90 Time (sec) Max RMS Mean Min
March 7, 2001 MEIT-2001 / Section 13 / Page 40 Impact of the Microgravity Environment on Experiments Acceleration Levels of the Space Shuttle and the MIM Flotor g) µ µ µ µ Acceleration ( Acceleration
Time (seconds)
March 7, 2001 MEIT-2001 / Section 13 / Page 41 Impact of the Microgravity Environment on Experiments Flotor X Acceleration g) µ µ µ µ Acceleration ( Acceleration
Time (seconds)
March 7, 2001 MEIT-2001 / Section 13 / Page 42 Impact of the Microgravity Environment on Experiments Power Spectral Densities for the Shuttle and MIM Flotor Accelerations
7 7 1 10 1 10 6 6 1 10 1 10 5 5 1 10 1 10 4 4 1 10 1 10 3 3 1 10 1 10 100 100 10 10 1 1 0.1 0.1 0.01 0.01 Y Acceleration (micro-g^2/Hz) X Acceleration (micro-g^2/Hz) 3 3 1 10 1 10 4 4 1 10 3 1 10 3 0.01 0.1 1 10 100 1 10 0.01 0.1 1 10 100 1 10 Frequency (Hz) Frequency (Hz) 7 1 10 6 1 10 5 1 10 4 1 10 3 1 10 100 10 1 0.1 0.01 Z Acceleration (micro-g^2/Hz) 3 1 10 4 1 10 3 DPID, XY: 2 Hertz, Z: 0.1 Hertz 0.01 0.1 1 10 100 1 10 File: D7081621 Frequency (Hz)
March 7, 2001 MEIT-2001 / Section 13 / Page 43 Impact of the Microgravity Environment on Experiments MIM Driven Mode - Random
March 7, 2001 MEIT-2001 / Section 13 / Page 44 Impact of the Microgravity Environment on Experiments MIM Driven Mode - 5 Hz
March 7, 2001 MEIT-2001 / Section 13 / Page 45 Impact of the Microgravity Environment on Experiments MIM-1 Operations on Mir
Operational from May 1996 to January 1998
3000 hours of operations supporting material science experiments: • Diffusion in liquid metals, Nucleation in glasses, Particle pushing, Semiconductor crystal growth, Protein crystal growth, Liquid- vapor interface dynamics
Acceleration data collected for most of this time with sampling rate up to 1000 s/s for several minutes and continuous time recordings up to seven days at lower sampling rates
March 7, 2001 MEIT-2001 / Section 13 / Page 46 Impact of the Microgravity Environment on Experiments Accelerations on Mir as Measured with the MIM
Mir Acceleration in Y 20
10
0 Acceleration (mg)
10
20 0 50 100 150 200 250 300
Max Time (Seconds) RMS Mean Min
March 7, 2001 MEIT-2001 / Section 13 / Page 47 Impact of the Microgravity Environment on Experiments Accelerations on Mir as Measured with the MIM
Mir Acceleration 20
10
0 Acceleration (mg)
10
20 0 50 100 150 200 250 300 Time (seconds) Max RMS Mean Min
March 7, 2001 MEIT-2001 / Section 13 / Page 48 Impact of the Microgravity Environment on Experiments Accelerations on Mir as Measured with the MIM
Stator Acceleration in Y Direction 8 1 10 7 1 10 6 1 10 5 1 10 4 1 10 3 1 10 100 10 1 Power Spectral Density (microg^2/Hz) 0.1 0.01 3 0.01 0.1 1 10 100 1 10 Frequency (Hz) MIR Environment ISS Requirement
March 7, 2001 MEIT-2001 / Section 13 / Page 49 Impact of the Microgravity Environment on Experiments Accelerations on Mir as Measured with the MIM
9 Stator Acceleration in Z Direction 1 10 8 1 10 7 1 10 6 1 10 5 1 10 4 1 10 3 1 10
100 Power Spectral Density (microg^2/Hz) 10
1 3 0.01 0.1 1 10 100 1 10 Frequency (Hz)
MIR Environment ISS Requirement
March 7, 2001 MEIT-2001 / Section 13 / Page 50 Impact of the Microgravity Environment on Experiments Accelerations on Mir as Measured with the MIM
March 7, 2001 MEIT-2001 / Section 13 / Page 51 Impact of the Microgravity Environment on Experiments
Accelerations on Mir as Measured with the MIM
Flotor Acceleration in Y 20
10
0 Acceleration (mg)
10
20 0 5 10 15 20 25 30 35 40 45 Time (hours) Max RMS Mean Min
March 7, 2001 MEIT-2001 / Section 13 / Page 52 Impact of the Microgravity Environment on Experiments
Accelerations on Mir as Measured with the MIM
Flotor Acceleration in Z 20
10
0 Acceleration (mg)
10
20 0 5 10 15 20 25 30 35 40 45 Time (hours) Min RMS Mean Max
March 7, 2001 MEIT-2001 / Section 13 / Page 53 Impact of the Microgravity Environment on Experiments Mean Acceleration on an Expanded Scale
Flotor Acceleration in Y
0.01
0 Acceleration (mg)
0.01
0 5 10 15 20 25 30 35 40 45 Time (hours)
March 7, 2001 MEIT-2001 / Section 13 / Page 54 Impact of the Microgravity Environment on Experiments Mean Acceleration on an Expanded Scale
Flotor Acceleration in Z
0.01
0 Acceleration (mg)
0.01
0 5 10 15 20 25 30 35 40 45 Time (hours)
March 7, 2001 MEIT-2001 / Section 13 / Page 55 Impact of the Microgravity Environment on Experiments Mean Acceleration on an Expanded Scale
Flotor Acceleration in Y
0.005
0 Acceleration (mg)
0.005
20 21 22 23 24 25 26 Time (hours)
March 7, 2001 MEIT-2001 / Section 13 / Page 56 Impact of the Microgravity Environment on Experiments Mean Acceleration on an Expanded Scale
Flotor Acceleration in Z
0.005
0 Acceleration (mg)
0.005
20 21 22 23 24 25 26 Time (hours)
March 7, 2001 MEIT-2001 / Section 13 / Page 57 Impact of the Microgravity Environment on Experiments Spectrum for Intermediate Frequency Acceleration on Mir
6 Stator Acceleration in X Direction 1 10 5 1 10 4 1 10 3 1 10
100
10
1
0.1 Power Spectral Density (microg^2/Hz) 0.01 3 1 10 4 3 3 1 10 1 10 0.01 0.1 1 10 100 1 10 Frequency (Hz)
March 7, 2001 MEIT-2001 / Section 13 / Page 58 Impact of the Microgravity Environment on Experiments Comments on Acceleration Environment on Mir and the Shuttle
Over most of the frequency band covered by the ISS specification the acceleration levels on the Mir are well below the specification for isolated racks
The same holds true for the acceleration levels on the shuttle Coupled with the observed sensitivity of diffusion and internal fluid flow to g- jitter at these levels this indicates that the current specification for isolated racks on the ISS is not conservative for fluid based experiments
March 7, 2001 MEIT-2001 / Section 13 / Page 59 Impact of the Microgravity Environment on Experiments Closing Remark
Experimenters should be aware of the vibration levels on the ISS
March 7, 2001 MEIT-2001 / Section 13 / Page 60