Spacecraft Spin Stabilization Using a Transverse Wheel for Any Inertia Ratio

1999 ◽  
Vol 22 (6) ◽  
pp. 768-775 ◽  
Author(s):  
Richard A. Fowell ◽  
Richard I. Milford ◽  
John F. Yocum
Keyword(s):  
Spin Stabilization ◽  
Spacecraft Spin

scholarly journals Dispersive O<sup>+</sup> conics observed in the plasma-sheet boundary layer with CRRES/LOMICS during a magnetic storm

1996 ◽  
Vol 14 (6) ◽  
pp. 593-607
Author(s):  
M. Wüest ◽  
D. T. Young ◽  
M. F. Thomsen ◽  
B. L. Barraclough ◽  
H. J. Singer ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Plasma Sheet ◽  
Pitch Angle ◽  
Radiation Effects ◽  
Low Frequency ◽  
Particle Interactions ◽  
Plasma Sheet Boundary Layer ◽  
Angle Scattering ◽  
Central Plasma ◽  
Spacecraft Spin

Abstract. We present initial results from the Low-energy magnetospheric ion composition sensor (LOMICS) on the Combined release and radiation effects satellite (CRRES) together with electron, magnetic field, and electric field wave data. LOMICS measures all important magnetospheric ion species (H+, He++, He+, O++, O+) simultaneously in the energy range 60 eV to 45 keV, as well as their pitch-angle distributions, within the time resolution afforded by the spacecraft spin period of 30 s. During the geomagnetic storm of 9 July 1991, over a period of 42 min (0734 UT to 0816 UT) the LOMICS ion mass spectrometer observed an apparent O+ conic flowing away from the southern hemisphere with a bulk velocity that decreased exponentially with time from 300 km/s to 50 km/s, while its temperature also decreased exponentially from 700 to 5 eV. At the onset of the O+ conic, intense low-frequency electromagnetic wave activity and strong pitch-angle scattering were also observed. At the time of the observations the CRRES spacecraft was inbound at L~7.5 near dusk, magnetic local time (MLT), and at a magnetic latitude of –23°. Our analysis using several CRRES instruments suggests that the spacecraft was skimming along the plasma sheet boundary layer (PSBL) when the upward-flowing ion conic arrived. The conic appears to have evolved in time, both slowing and cooling, due to wave-particle interactions. We are unable to conclude whether the conic was causally associated with spatial structures of the PSBL or the central plasma sheet.

Spin Stabilization of an Air Ambulance Litter

2020 ◽  
Author(s):  
Christopher Forden ◽  
Yanuel Trinidad ◽  
Ryan von Chance-Stutler ◽  
Andrew Bellocchio ◽  
James Bluman ◽  
...  
Keyword(s):  
Inertial Measurement Unit ◽  
Angular Acceleration ◽  
Measurement Unit ◽  
Control Laws ◽  
New Approach ◽  
Air Ambulance ◽  
Special Operations ◽  
Spin Stabilization ◽  
Rescue Hoist ◽  
Prototype Design

Abstract This paper proposes a new approach to stabilize the spin of a suspended litter during air ambulance rescue hoist operations. Complex forces generated by the helicopter’s downwash may cause a patient suspended in a rescue litter to spin violently. In severe cases, the spin destabilizes the suspended load, risks injury to the patient, and jeopardizes the safety of the aircrew. The presented design employs an anti-torque device to arrest the spin that is safer and faster than a tagline and is without the tactical constraints of the tagline. The device follows tailored control laws to accelerate a flywheel attached to the litter, thereby generating sufficient angular momentum to counteract the spin and stabilize the suspended litter. An inertial measurement unit (IMU) measures the position, angular velocity, and angular acceleration of the litter and delivers this information to a microcontroller. The research and prototype design were developed under the support of the U.S. Army 160th Special Operations Aviation Regiment (SOAR).

Detection of Semiquinone Radicals of N-Acylcatecholamines in Aqueous Solution

1985 ◽  
Vol 40 (7-8) ◽  
pp. 535-538 ◽  
Author(s):  
Martin G. Peter ◽  
Hartmut B. Stegmann ◽  
Hoang Dao-Ba ◽  
Klaus Scheffler
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Esr Spectra ◽  
Semiquinone Radicals ◽  
Spin Stabilization ◽  
Michael Type Addition ◽  
Nitrogen Nucleophiles

Abstract ESR-spectra were recorded during the oxidation of N-acetyldopamine and N-β-alanyldopamine in aqueous solutions. Semiquinone radicals were detected under conditions of spin stabilization by Zn2+ ions. The appearance of the spectra was the same in the presence or in the absence of proteins. No evidence was obtained for the formation of products that could have arisen eventually from intermolecular Michael-type addition of nitrogen nucleophiles.

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