Analysis of Vibratory Data Collected by the Space Acceleration Measurement System (SAMS) on Blue Origin, June 19, 2016 Cover

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Analysis of Vibratory Data Collected by the Space Acceleration Measurement System (SAMS) on Blue Origin, June 19, 2016

Gravitational and Space Research

Volume 5 (2017): Issue 2 (December 2017)

By: Kevin McPherson, Eric Kelly, Jennifer Keller, Ajeeth Ibrahim, Erika Wagner and Kenneth Hrovat

Open Access

|Jul 2020

Figures & Tables

SAMS sensor location within the New Shepard vehicle. (A) The New Shepard vehicle, showing the capsule on top. (B) A top-down cross-sectional view of the capsule with six payload stacks uniformly distributed around its perimeter; the payload locker that housed SAMS was at about the 8 o’clock, position #3. (C) A perspective view of the SAMS payload locker. (D) A top-down view of the SAMS sensor mounted within its payload locker with cabling for power and data.

Per-axis plot of SAMS acceleration measurements up to 204.2 Hz versus time for three main periods. Note that the mean value computed during the Microgravity Period is subtracted off. The colored bands at the top represent flight periods. The pink band (top) demarks the Separation Period, which was ~2.8 min in duration from 1 s after the Separation event to the Coast End event. The blue band (middle) indicates the Coast Period, which was ~2.2 min in duration from the Coast Start event to the Coast End event. The green band (bottom) marks the very quiet Microgravity Period, which was ~46.8 s in duration from 521.86 s to 568.61 s.

Spectrogram computed from SAMS measurements and Blue Origin flight information. This three-dimensional plot shows the acceleration spectrum via color-mapped power spectral density (PSD) magnitude versus frequency on the vertical axis, and versus time on the horizontal axis. The PSD color scale was chosen for emphasis during free fall and represents the squared deviation of the acceleration with respect to the mean acceleration during free fall. Although a Hanning window was used to reduce spectral leakage for each of the constituent PSDs in this spectrogram (k = 918), the strong signal near zero frequency should be disregarded as attributable to spectral leakage from sensor bias.

A cumulative RMS acceleration versus frequency plot for the three main periods of interest. The Post-Separation Period (red) and Coast Period (blue) mostly track each other, and the New Shepard Microgravity Period stays well below 1 mg RMS up to the sensor cutoff frequency.

Comparison of RMS acceleration levels below 10 Hz versus microgravity duration for several different types of platforms (Ross, 2001).

Root-mean-square accelerations calculated for the Coast Period_

	Root-Mean-Square Acceleration (mg)
Frequency	X-Axis	Y-Axis	Z-Axis	Total
Below 50 Hz	0.32	1.23	1.00	1.23
Below 200 Hz	10.10	4.13	7.03	11.14

Five-number statistical summary of acceleration magnitudes during the Microgravity Period_

	Acceleration Magnitude (mg)
Percentile	X-Axis	Y-Axis	Z-Axis	Total
25th	0.10	0.06	0.07	0.25
50th	0.22	0.14	0.16	0.36	Median
75th	0.37	0.24	0.27	0.52
97.5th	0.76	0.48	0.56	0.94
MAX	2.27	1.18	1.45	2.77

Five-number statistical summary of acceleration magnitudes during the Post-Separation Period_

	Acceleration Magnitude (mg)
Percentile	X-Axis	Y-Axis	Z-Axis	Total
25th	0.28	0.17	0.20	0.47
50th	1.45	0.62	0.92	3.37	Median
75th	8.60	3.07	5.01	11.91
97.5th	51.11	10.25	16.92	54.75
MAX	230.48	143.29	178.41	276.18

Root-mean-square accelerations calculated for the Microgravity Period_

	Root-Mean-Square Acceleration (mg)
Frequency	X-Axis	Y-Axis	Z-Axis	Total
Below 50 Hz	0.01	0.07	0.03	0.08
Below 200 Hz	0.32	0.20	0.23	0.45

Root-mean-square accelerations calculated for the Post-Separation Period_

	Root-Mean-Square Acceleration (mg)
Frequency	X-Axis	Y-Axis	Z-Axis	Total
Below 50 Hz	0.25	0.94	0.75	1.23
Below 200 Hz	8.60	3.66	6.06	11.14

Five-number statistical summary of acceleration magnitudes during the Coast Period_

	Acceleration Magnitude (mg)
Percentile	X-Axis	Y-Axis	Z-Axis	Total
25th	0.29	0.18	0.21	0.47
50th	2.38	0.91	1.46	5.13	Median
75th	10.29	3.51	5.81	13.68
97.5th	57.34	10.56	17.64	59.93
MAX	230.48	143.29	178.41	276.18

DOI: https://doi.org/10.2478/gsr-2017-0006 | Journal eISSN: 2332-7774

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Language: English

Page range: 2 - 10

Published on: Jul 21, 2020

Published by: American Society for Gravitational and Space Research

In partnership with: Paradigm Publishing Services

Publication frequency: 2 issues per year

Keywords:

Commercial Spaceflight,

Microgravity Vibratory Environment,

Acceleration Measurement,

Platform Characterization,

Vibratory Data Analysis,

Microgravity Research,

Related subjects:

Life sciences, other,

Materials sciences,

Materials sciences, other,

© 2020 Kevin McPherson, Eric Kelly, Jennifer Keller, Ajeeth Ibrahim, Erika Wagner, Kenneth Hrovat, published by American Society for Gravitational and Space Research
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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