hypothesis, it remains unclear whether the disturbance was naturally occurring or an effect of
the OMS burn. The final objective, the use of artificial airglow to make natural ionospheric
irregularities more easily observable, was accomplished when the STS-122/1E completed an
OMS burn in a region of strong natural ionospheric irregularities. The burn exhaust created
artificial airglow that enhanced the irregularities present in the ionosphere. The enhanced
features were easily observed by ground-based imagers. Ground based radar was used to
observe the effect of shuttle OMS burns on the ionosphere at midlatitudes during shuttle flights
STS-110/8A, STS-128/17A, and STS-119/15A. The cases of STS-110 and STS-128 showed that the
exchange of charges by exhaust molecules traveling at hypersonic speeds in the ionosphere
yields high energy ion beams that create a backscatter signature detectable by radar that lasted
from 30 to 90 seconds to over 20 minutes. The STS-119 case was the first reported detection of
a rocket engine burn in the F-region, the topside and densest layer of the ionosphere, at a
range of over 700 kilometers. The burn was detected by radar as a disturbed region of
enhanced high frequency (HF) backscatter that lasted for 40 minutes. This disturbance was
unique to the burn and was not seen near this location in the 2 weeks prior to or after the burn
event. SIMPLEX demonstrated that rocket exhaust products can be used to better observe
irregular features in the ionosphere (Bernhardt 2012).
PUBLICATION(S)
Bernhardt P, Ballenthin J, Baumgardner J, et al. Ground and space-based measurement of
rocket engine burns in the Ionosphere, IEEE Transactions on Plasma Science. 2012;40:1267-
- doi: 10.1109/TPS.2012.2185814.
This investigation is complete; however additional results are pending publication.