The Plasma Diagnostics Package, which was flown aboard STS-3 as part of the Office of Space Science first Shuttle payload (OSS-1), recorded the effects of various chemical releases from the Orbiter. Changes in the plasma environment were observed to occur during flash evaporator system releases, water dumps and maneuvering thruster operations. During flash evaporator operations, broadband Orbiter-generated electrostatic noise was enhanced and plasma density irregularities (AN/N) were observed to increase by 3 to 30 times with a spectrum which rose steeply and peaked below 6 Hz. Ions with energies up to several hundred eV were also observed during one flash evaporator operation. In the case of water dumps, background electrostatic noise was enhanced at frequencies below about 3 kHz and suppressed at frequencies above 3 kHz during the dump, and AN/N was also seen to increase by 5 to 6 times. Various changes in the plasma environment were effected by primary and vernier thruster operations, including increases in electron density by as much as 3 orders of magnitude, neutral pressure increases to as high as 10" 1 * torr from the nominal 10 torr, and perturbations in the spacecraft potential by several volts, particularly when measured relative to the plasma potential in the wake. Thruster activity also stimulated electrostatic noise with a spectrum which peaked at approximately 0.5 kHz. In addition, ions with energies up to 1 keV were seen during some thruster events.

One of the objectives of the Plasma Diagnostics Package (PDP) instrumentation on Spacelab 2 was to obtain information about the plasma wake of the shuttle orbiter. We present plasma density and electron temperature data obtained (1) while the PDP was attached to the shuttle remote manipulator system and (2) while the PDP was a free‐flying satellite. Wake crossings by the PDP from ∼40 m to ∼240 m behind the orbiter provide information about the structure of the mid and far wake of the orbiter. As expected, the wake is characterized by density depressions, relative to the ambient ionospheric plasma, and by enhancements of the electron temperature, particularly in the near and mid wake. The observed electron temperature enhancements appear to be in line with previous spacecraft observations.

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The first active beam‐plasma experiments utilizing the space shuttle were carried out in March 1982 as part of the NASA Office of Space Science mission on the third space shuttle flight. A fast pulse electron generator emitted a 1‐keV, 100‐mA electron beam in either a continuous (dc) mode or an on/off modulated mode in the ELF to HF frequency range. Stimulated electrostatic and electromagnetic waves and associated plasma effects were measured with the plasma diagnostics package as it was maneuvered through and near the beam by the remote manipulator system. For the dc beam the wave spectrum was electrostatic, was peaked in the 300‐ to 500‐Hz range with a spectral density of 4 × 10−3 V2 m−2 Hz−1, and was unpolarized. Above the nominal lower hybrid resonance frequency the intensity decreased but was polarized. Strong emissions near the electron gyrofrequency and the plasma frequency were occasionally detected. The background spectrum was similar to the dc case for VLF and ELF modulations, but the emissions at the modulation frequency were more electromagnetic and more intense with field strengths of up to 1 Vm−1.