Relativistic rocketry and the requirements for instellar flight

The kinematic requirements for interstellar travel are examined, and the theoretical performance of nuclear and photon rockets is evaluated. The first part of the paper contains a detailed discussion of relativistic rocketry, including the problems of time-dilatation in an accelerating system, and the twin paradox. In the latter part of the...

Free-flight static stability measurements of cones in hypersonic flow

The longshot free-piston cycle: Part 1 - theory

An approximate analytical solution is presented for the free-piston cycle in the VKI Longshot Hypersonic Tunnel. The Longshot differs from a conventional gun tunnel in that a heavy piston is used to compress the nitrogen test gas, which is then trapped at the end of the barrel at very high pressure by the closing of a system of check valves as...

Theoretical performance study of the free-piston shock tube

Formulas and charts are presented for predicting the performance of a free-piston shock tube using helium or hydrogen as the driver gas and real air as the test gas. The use of a piston to adiabatically compress the test gas in what is otherwise a conventional shock tube affords the practical possibility of obtaining shock Mach numbers above 40...

On the pressure decay rate in the longshot reservoir

Pressure probes in free molecule flow

When the mean free path becomes a significant fraction of a characteristic dimension of a pressure probe, the usual continuum formulae relating the measured pressure to the free-stream pressure and Mach number are no longer valid. The present paper treats the case where the mean free path is so large compared with the probe diameter that...

Pressure probes in free molecule flow