TIM FURNISS / LONDON
Four-step strategy devised to rescue ESA's communication satellite after Ariane failure
The European Space Agency's (ESA) Artemis communications and navigation technology demonstration satellite made its first orbit-raising manoeuvre on 19 July. Artemis was stranded in the wrong orbit with Japan's BSAT-2B satellite on 12 July after a botched Ariane 5 launch.
ESA hopes to eventually place the spacecraft in geostationary orbit (GEO) through a series of burns of the satellite's liquid apogee boost motor and using the craft's ion propulsion system. It is hoped that Artemis will still have a useful operational life, although this may not reach the planned 10 years.
To move the satellite, the ESA-Alenia Spazio-Telespazio Artemis team has devised a four-step strategy which started with the apogee boost motor firing on 19 July to raise the apogee using several burns at the perigee or low point of the orbit.
The first burn raised the apogee from 17,487km to 19,164km. The second phase is intended to circularise the orbit using a series of apogee and perigee manoeuvres to place the craft into a quasi-circular orbit at 31,000km.
By 23 July Artemis was in a 2,446km by 30,865km orbit. The satellite will be commissioned and activated in this sub-geostationary orbit, before the ion propulsion system, originally intended to be used for evaluation and demonstration, will place the craft in its planned 36,000km circular GEO. The first burn of the ion propulsion system is planned for September.
This final stage to reach GEO will take several months, says ESA. The recovery scenario offers the best chance to put the satellite into GEO, saving enough chemical fuel and xenon ion propulsion propellant to support several years of nominal operation, adds the agency. ESA is unable to predict the life of Artemis until after the satellite has reached its sub-GEO orbit.
Source: Flight International
