L= distance between mass centers of satellites m1 and m2, tether length if m1 � m2 ,m L 0 = initial tether length, m M = total system mass, kg mi = mass of satellite i ,k g mt = tether mass, kg ri = position vector of mass mi from the system center of mass, m ˆ r1 = r1/a β, η = relative in-plane and out-of-plane swing angles between m1 and m2, respectively, deg βmax ,η max = maximum values of β and η, respectively, deg ˙ β0 = ˙ β at θ = 0 � Ha1 = maximum altitude decrease of m1 at apogee, m � Hi = altitude gain of satellite mass mi ,m � Hp2 = maximum altitude gain of m2 at perigee, m � L = decrease in the initial tether length L 0 during tether retrieval, m δ = ratio of in-plane swing rate ˙ β to the orbital rate � μ = gravitational constant, m 3 s −2 � = orbital rate, (μ/a 3 ) 1/2 , rad/s

Review on Dynamics and Control of Nonelectrodynamic Tethered Satellite Systems

An overview of whistler wave phenomena in space and laboratory plasmas is given. Common features and different approaches between laboratory and space plasma research are pointed out. Both research activities have discovered a rich variety of whistler wave effects. Many useful applications have emerged. Open research topics and interactions between lab and space research on whistlers are pointed out.

http://www.physics.ucla.edu/plasma-exp/references/publications/GRL/JGR-104-14395-1999.pdf

Whistler waves in space and laboratory plasmas

Further laboratory measurements of the beam-plasma discharge (BPD) produced when an energetic electron beam traverses an initially neutral gas are presented. The experimental data indicate that the critical beam current Ic at energy V, magnetic field B, and system length L required for ignition obeys the empirical relationship Ic ∝ V3/2/B0.7 PL at pressures P < 2 × 10−5 torr. This relationship appears to primarily describe the accumulation of ambient plasma density, collisionally produced by the beam itself, to a critical value where ωpe² ≈ ωce² at which ignition occurs. Additional measurements of the narrow-band cyclotron-related waves (fce < f < 1.4fce) observed at beam currents below BPD threshold do not clearly establish whether this instability is a necessary precursor to the BPD. The relevance of these experiments to past and planned electron beam experiments in space is briefly discussed.

Further laboratory measurements of the beam-plasma discharge. [for aerospace technology application]

The concept of tethered satellite system (TSS) promises to revolutionize many aspects of space exploration and exploitation. It provides not only numerous possible and valuable applications, but also challenging and interesting problems related to their dynamics, control, and physical implementation. Over the past decades, this exciting topic has attracted significant attention from many researchers and gained a vast number of analytical, numerical and experimental achievements with a focus on the two essential aspects of both dynamics and control. This review article presents the historic background and recent hot topics for the space tethers, and introduces the dynamics and control of TSSs in a progressive manner, from basic operating principles to the state-of-the-art achievements.

Advances in dynamics and control of tethered satellite systems

We present a survey of a very incomplete subject. The best-developed and simplest theories for current collection in magnetic fields are steady-state collisionless theories, and these must be understood before departures from them can be analyzed usefully, so we begin with a review of them. Recent numerical results indicate that steady-state collisionless Laplace-limit currents remain substantially below the Parker-Murphy (1967) canonical upper bound out to very large electrode potentials and approach it as a limit only very slowly if at all. Attempts to correct this theory for space-charge effects lead to potential disturbances which extend to infinite distance along the electrode's magnetic shadow, unless collisional effects are also taken into account. However, even a small amount of relative plasma drift motion, such as that involved in a typical rocket experiment, can change this conclusion fundamentally. It is widely believed that time-averaged current collection may be increased by effects of plasma turbulence, and we review the available evidence for and against this contention. Steady-state collisionless particle dynamics predicts the existence of a toroidal region of trapped orbits which surrounds the electrode. Light emissions from this region have been photographed, indicating that collisional ionization may also occur there, and this, and/or scattering by collisions or possibly turbulent fluctuations in this region, may also increase current collection by the electrode. We also discuss effects on particle motions near the electrode, associated with “breakdown of magnetic insulation” in the region of large electric fields near it.

Current collection by probes and electrodes in space magnetoplasmas: A review

Electrical behavior of a Shuttle Electrodynamic Tether System (SETS)

The tethered mother-daughter rocket experiment (Charge 2) was carried out by a NASA sounding rocket, Black Brant 9, at White Sands Missile Range in New Mexico in December 1985. It was intended to perform a new type of active experiment in space by applying a high voltage between the two payloads, as well as by injecting an electron beam from the tethered rocket system. An insulated conductive wire connecting the two payloads was deployed up to its maximum length of 426 m during the flight. An electron beam from 0.5 to 48 mA at 1 keV was injected from the mother payload. A voltage up to 500 V was applied between the two payloads with and without the beam injection. This paper describes the initial results on the electrodynamic effects induced by the potential difference between the two payloads. Measurements of the v×B electromotive force and the voltage/current characteristics up to 500 V have been explained by a model in which the ion current to the negatively biased payload effectively limited the tether current. Two kinds of VLF waves were observed when the bias voltage was applied between the two payloads; narrow-band emission at 2–4 kHz and broadband emission up to 15 kHz, depending on the applied voltage. The characteristic features of these emissions suggest that the lower hybrid instability (modified two-stream instability) driven by the potential difference between the rocket and the ambient plasma was responsible for the wave generation.

Tethered rocket experiment (Charge 2): Initial results on electrodynamics

The data obtained in the most recent Japan-US tether rocket experiment CHARGE 2 have been further analyzed. The interaction of the moving tether system across the geomagnetic field with the ionospheric plasma can be explained by a simple model of the current through a plasma. The response of the tether system when a high voltage is applied is studied and 500 volts could be applied without any appreciable discharge. The detected signal of the wave excited by an application of high voltage between the mother and daughter rocket and by a pulse modulated electron beam is also studied.

Further analysis of the results from a series of tethered rocket experiments

The floating potential of a rocket and the return current distribution were measured simultaneously in the S-520-2 electron beam experiment in the ionosphere. When an electron beam is emitted perpendicular to the geomagnetic field, it returns back to the rocket surface azimuthally opposite (180°) to the electron gun and this results in a suppression of the floating potential. An apparent spurious increase of the floating potential of the rocket when the electron beam directly hits the floating probes causing the charge-up of those probes is also pointed out.

K. I. Oyama

Papers

Electrical behavior of a Shuttle Electrodynamic Tether System (SETS)

Tethered rocket experiment (Charge 2): Initial results on electrodynamics

Further analysis of the results from a series of tethered rocket experiments

Floating potential and return current measurements in a rocket‐borne electron beam experiment

Results from a tethered rocket experiment (Charge-2)