Project Description DEFINE

DEnsity FIeld in Neutrals and Electrons (DEFINE) is a sounding rocket campaign dedicated to the investigation of the density and temperature field in the mesos- and lower thermosphere (MLT), as well as its composition and quantification of the energy budget.

Direct measurements in this altitude range are particularly challenging and rare, as they cannot be achieved with other methods such as balloons or satellites. At the same time, the MLT region is particularly interesting because, in the transitional zone to space, both dynamic processes from the lower atmospheric layers and dynamic processes triggered by the Sun from the layers above interact.
In the density field, the signatures of these processes become visible. Therefore, all relevant parameters, namely the concentration of neutral gas, electrons, and atomic oxygen, must be determined with high-precision in-situ measurements onboard research rockets.

The results contribute to the overall understanding of the Earth's atmosphere and thus to the long-term improvement of climate models, weather forecasts, and predictions of impacts on near-Earth space objects.
For the first time, IAP aims to measure in-situ in the altitude range to up to 160 km. For this task, we build on our expertise from successful previous projects (e.g., PMWE, WADIS, ECOMA, MIDAS).
The rocket-borne measurements are complemented by ground-based airglow and wind measurements using the ALOMAR RMR Lidar system, which provides additional information about wave structures. The airglow imagers are situated in Andenes, Kiruna, and Skibotn, allowing for horizontal observations over a distance of approximately 250 km.
The DEFINE measurements will be conducted during an approximately 10-day campaign at the Andøya Space Center on the northern Norwegian island of Andøya. In parallel with these measurements, our Swedish partner will carry out rocket measurements as part of the ORIGIN project (ESRANGE, Kiruna in Sweden), on whose payload there are also IAP experiments for electron, ion, and neutral gas density measurements, as well as temperature measurement (CONE, PIP, WPE).

In addition to established measurements (WPE, PIP, CONE), new developments are being made to adapt to the extended altitude range (CONE4 Sensor). Project partners complement the IAP measurements with their respective expertise. The Institute of Space Systems at the University of Stuttgart (IRS) is responsible for measurements of atomic oxygen using the FIPEX instrument.
A collaboration with Clemson University (USA) provides additional measurements of neutral gas density and temperature using an established laboratory instrument with lower spatial resolution.
The Meteorological Department of Stockholm University (MISU) is leading the ORIGIN project (Swedish Space Corporation) and is supporting the IAP payload with a photometer for measuring emissions from chemical processes. The Mobile Rocket Base (MORABA) of the German Aerospace Center is responsible for payload construction and the execution of the DEFINE campaign.
The DEFINE campaign at Andøya Space in Norway is planned to take place simultaneously with the Swedish ORIGIN project at ESRANGE in Sweden in March/April 2015.