Fundamental Physics and Chemistry Space Science in the Twenty-First Century -- Imperatives for the Decades 1995 to 2015 (1988) / Chapter Skim
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5. Expected Research Prior to 1995
5. Expected Research Prior to 1995
Pages 30-37
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From page 30... ...
The Shuttle test will provide some information on gyro drift at reduced g but will not be able to establish the low drift rates of the gyros required to carry out the actual experiment.
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From page 31... ...
A superconducting equivalence experunent has been designed with the potential of testing the equivalence of gravitational and inertial mass to a projected sensitivity of one part in 10~5 on a Shuttle flight and one part in 10~8 on a zero-g free flyer.
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From page 32... ...
Two concentric test masses, a solid rod and a hollow cylinder, are constrained by magnetic bearings so that they are free to move only along a common axis (see Figure 5.2~. As they orbit the Earth with fixed orientation in inertial space, they are subjected simultaneously to the centrifugal acceleration of the orbital motion and the gravitational attraction of the Earth.
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From page 33... ...
One feature of the experunent is that the perturbing ejects due to gravitational field gradients can be reduced to negligible levels by making the center of mass of the two test masses coincident. This ~ done by sensing the differential displacement signals at twice the orbital frequency and using the signature in a null servo system.
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From page 34... ...
Despite the low altitude, and the corresponding highdegree and high-order gravity field solution required, valuable results could be obtained if the range and Doppler measurements were sufficiently accurate. There also may be an opportunity for accurate lower degree and lower order gravity field solutions and thus improved Earth-Mars distance determinations when the spacecraft orbital altitude is raised at the end of the planetary observation period.
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From page 35... ...
Several theoretical lines of argument lead to the expectation that neutron stars secreting from binary companions should be able to spin up to angular frequencies in which they are subject to relativistic instabilities, with the angular momentum supplied from the accreting disk continually radiated away in gravitational waves. Such objects would be pulsars in both gravitational waves and x-rays.
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From page 36... ...
A Shuttle instrument for timing observations of the brightest compact x-ray sources offers the exciting possibility of discovering new phenomena in Secreting binary systems containing a neutron star. For example, there are strong reasons to believe that in such a system a neutron star with a weak magnetic field can be spun up by accretion to periods so short that the star is subject to general relativistic instabilities.
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From page 37... ...
The Deep Space Net has a stated goal of unproving frequency standards, transponders, and transmission technology to make use of frequency stabilities of 10-~7 in periods of thousands of seconds. Should this be implemented, the other noise sources will dorn~nate.
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