Abstract-A microprocessor clock generator based upon an analog phase-locked loop (PLL) is described for deskewing the internal logic control clock to an external system clock. This PLL is fully integrated onto a 1.2-million-transistor microprocessor in 0 . 8 -p CMOS technology without the need for external components. It operates with a lock range from 5 up to 110 MHz. The clock skew is less than 0.1 ns, with a peak-to-peak jitter of less than 0.3 ns for a 50-MHz system clock frequency.

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The Jupiter Observing Velocity Experiment (JOVE) is a solar-powered technology demonstration of rapid flight to outer solar system targets, performing a flyby of Jupiter 30 days after launch. This is achieved using a magnetic drag device to accelerate with the solar wind plasma. This “Wind Rider” propulsion system can potentially also decelerate against the Jovian magnetosphere dawn eddy, to enable Jupiter orbital insertion in future missions. The 16U cubesat bus contains scientific instruments to record the plasma parameters from the vicinity of the spacecraft, with principal measurements coming from a SPAN-I ion velocity sensor. This paper includes a description of the propulsive mechanisms and supporting subsystems and trajectory simulation results derived from solar wind measurements over the past two solar cycles. The objectives of the JOVE technology demonstrator design include: (1) verify Wind Rider stability and control; (2) characterize loss mechanisms in the solar wind, such as resistive losses in the plasma, as well as the magnetic field transient interaction time; (3) operate onboard instruments to measure the velocity and direction of the solar wind (SPAN-Ai) and speed of the spacecraft relative to the Earth (radio Doppler shift), to enable precision navigation on future science missions; and (4) characterize the Lift-to-Drag ratio of the plasma magnetic field. (The lift force enables lateral course control and maneuvering within the solar wind.) Applying existing scientific data from Voyagers and other deep space probes into new engineering models was important for enabling new insights about Wind Rider propulsion. It enables more science to be performed in a shorter amount of time, across the Jovian system.

A new class of reaction drive is discussed, in which reaction mass is expelled from a vehicle using power extracted from the relative motion of the vehicle and the surrounding medium, such as the solar wind. The physics of this type of drive are reviewed and shown to permit high velocity changes with modest mass ratio while conserving energy and momentum according to well-established physical principles. A comparison to past propulsion methods and propulsion classification studies suggests new mission possibilities for this type of drive. An example of how this principle might be embodied in hardware suggests accelerations sufficient for outer solar system missions, with shorter trip times and lower mass ratios than chemical rockets. Keywords: Propulsion, Reaction drive, Solar wind, External power, Dynamic pressure

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