Roland Rosta

Invited Article: Electric solar wind sail: Toward test missions

The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural solar wind dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the solar wind is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the solar system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations.

ESTCube-1 in-orbit experience and lessons learned

In this article, we report on the in-orbit experience - an overview of ESTCube-1 operations from the launch until the experiment, as well as on lessons learned from five years of development and almost two years of operations. Lessons are identified from the point of view of system engineering, electrical engineering, mechanical engineering, software engineering, testing and measurements, payload, and management. Detailed flight results of ESTCube-1 will be provided in dedicated articles. We hope that other teams can benefit from our experience.

The Network Infrastructure for the ROBEX Demomission Space

The demonstration mission space of the alliance Robotic Exploration of Extreme Environments (ROBEX) was a campaign on Mt. Etna in summer 2017. The network infrastructure and parts of the ground segment for this demonstration mission space were set up by the Mobile Rocket Base (MORABA) of the DLR. The ground segment included a control center which was based near Catania, Italy. Various terminals allowed for controlling a lander, a robotic rover and several experiment carriers which have been placed in 23 km airline distance on Mt. Etna. The distance was bridged by a radio link between the control center and a base camp at the demonstration site. From the base camp a shorter radio link of several hundreds of meters to the lander was established, and from there, the signal was distributed using several access points.