Publication archive

Publication archive

The scientific case and technical design description on which the mission was accepted within ESA's scientific programme. Note that the design details have been superseded, although the essential instrument principles and design objectives remain unaffected.
Published: 02 March 2001
We present results of an analysis of all 480 ks of Rossi X-ray Timing Explorer Proportional Counter Array data obtained from 17 May 1998 to 11 October 1998 on the luminous low mass X-ray binary GX 13+1. We analysed the spectral properties in colour-colour diagrams (CDs) and hardness-intensity diagrams (HIDs) and fitted the power spectra with a multi-Lorentzian model. GX 13+1 traces out a curved track in the CDs on a time scale of hours, which is very reminiscent of a standard atoll track containing an island, and lower and upper banana branch. However, both count rate and power spectral properties vary along this track in a very unusual way, not seen in any other atoll or Z source. The count rate, which varied by a factor of ~1.6, along a given track first decreases and then increases, causing the motion through the HIDs to be in the opposite sense to that in the CD, contrary to all other Z and atoll sources. Along a CD track, the very low frequency noise uniquely decreases in amplitude from ~5 to ~2% (rms). The high frequency noise amplitude decreases from ~4% to less than 1% and its characteristic frequency decreases from ~10 to ~5 Hz. The 5769 Hz quasi-periodic oscillation (QPO) found earlier is also detected, and no kHz QPOs are found. In addition the entire track shows secular motion on a time scale of about a week. The average count rate as well as the amplitude of the very low frequency noise correlate with this secular motion. We discuss a possible explanation for the peculiar properties of GX 13+1 in terms of an unusual orientation or strength of a relativistic jet.
Published: 02 July 2003
We present an overview of BeppoSAX Wide Field Cameras observations of the nine most frequent type I X-ray bursters in the Galactic center region. Six years of observations (from 1996 to 2002) have amounted to 7 Ms of Galactic center observations and the detection of 1823 bursts. The 3 most frequent bursters are GX354-0 (423 bursts), KS 1731-260 (339) and GS 1826-24 (260). These numbers reflect an unique dataset. We show that all sources have the same global burst behavior as a function of luminosity. At the lowest luminosities (LX < 2 < 1037 erg s1) bursts occur quasi-periodically and the burst rate increases linearly with accretion rate (clear in e.g. GS 1826-24 and KS 1731-260). At Lpers = 2 < 1037 erg s1 the burst rate drops by a factor of five. This corresponds to the transition from, on average, a hydrogen-rich to a pure helium environment in which the flashes originate that are responsible for the bursts. At higher luminosities the bursts recur irregularly; no bursts are observed at the highest luminosities. Our central finding is that most of the trends in bursting behavior are driven by the onset of stable hydrogen burning in the neutron star atmosphere. Furthermore, we notice three new observational fact which are difficult to explain with current burst theory: the presence of short pure-helium bursts at the lowest accretion regimes, the bimodal distribution of peak burst rates, and an accretion rate that is ten times higher than predicted at which the onset of stable hydrogen burning occurs. Finally, we note that our investigation is the first to signal quasi-periodic burst recurrence in KS 1731-260, and a clear proportionality between the frequency of the quasi-periodicity and the persistent flux in GS 1826-24 and KS 1731-260.
Published: 02 June 2003
Rosetta is an ESA cornerstone science mission to study, in situ, the environment of cometary nuclei and their evolution in the inner solar system. The main scientific objectives of the mission are to investigate the origin of the solar system by studying the origins of comets and to study the relationship between cometary and interstellar material. To enhance the scientific capabilities of the mission, the orbiter spacecraft will carry one probe, a lander which will land on the comet surface of the comet and perform investigations in situ. The Rosetta orbiter spacecraft will be launched in 2003 and, after a 9-year cruise, will begin the cometary close observation phase. By 2012 the in situ investigations will be complete. The lander is being developed by combined effort in Germany, Italy, France, the United Kingdom, Hungary, Finland and Austria.
Published: 02 May 1997
Scientific editor: B. Foing
Editor: A. Wilson The report to the 34th COSPAR Meeting covers the missions of the Scientific Programme of ESA in the areas of astronomy, Solar System exploration and fundamental physics.
Published: 02 September 2002
The four Cluster spacecraft were successfully launched in pairs by two Russian Soyuz rockets on 16 July and 9 August 2000. On 14 August, the second pair joined the first pair in highly eccentric polar orbits, with an apogee of 19.6 Earth radii and a perigee of 4 Earth radii. The very accurate orbital injection and low fuel consumption mean that spacecraft operations could continue for at least two more years after the nominal two-year mission. This is the first time that the Earth's magnetic field and its environment have been explored by a small constellation of four identical spacecraft. Preliminary results show that, as predicted, with four spacecraft we can obtain a detailed three-dimensional view of the Sun-Earth connection processes taking place at the interface between the solar wind and the Earth's magnetic field.
Published: 02 July 2001
Presented at the 34th AIAA Plasmadynamics and Lasers Conference, 23-26 June 2003, Orlando - Florida
Published: 24 June 2003
We present results from four Rossi X-Ray Timing Explorer observations of the bright, low-mass X-ray binary LMC X-2. During these observations, which span 1 yr and include over 160 hr of data, the source exhibits clear evolution through three branches on its hardness-intensity and color-color diagrams, consistent with the flaring, normal, and horizontal branches (FB, NB, HB) of a Z source and remarkably similar to Z tracks derived for GX 17+2, Sco X-1, and GX 349+2. LMC X-2 was observed in the FB, NB, and HB for roughly 30%, 40%, and 30%, respectively, of the total time covered. The source traces out the full extent of the Z in ~1 day, and the Z track shows evidence for secular shifts on a timescale in excess of a few days. Although the count rate of LMC X-2 is low compared with the other known Z sources due to its greater distance, the power density spectra selected by branch show very low frequency noise characteristics at least consistent with those from other Z sources.We thus confirm the identification of LMC X-2 as a Z source, the first identified outside our Galaxy.
Published: 21 June 2003
This international Conference was organised by the European Space Agency (ESA) in collaboration with the International Lunar Exploration Working Group (ILWEG). The papers presented covered a wide range of subjects, including future lunar missions, the technology needed to support these missions, science of the Moon itself, development of the Moon by humans and public outreach.
Published: 02 August 2000

Giorgio Saccoccia
Head of Propulsion and Aerothermodynamics Division

SMART-1 Media Day
3rd April 2003
ESA/ESTEC

Published: 04 April 2003

Guiseppe Racca
SMART-1 Project Manager

SMART-1 Media Day
3rd April 2003
ESA/ESTEC

Published: 04 April 2003

Eike Kircher
Head of Basic Technology Research Programme Section
Technology Programme Department

SMART-1 Media Day
3 April 2003
ESA/ESTEC

Published: 04 April 2003

Bernard H. Foing
Chief Scientist & SMART-1 Project Scientist

SMART-1 Media Day
3 April 2003
ESA/ESTEC

Published: 04 April 2003

Peter Rathsman
Project Manager
Sweedish Space Corporation

SMART-1 Media Day
3rd April 2003
ESA/ESTEC

Published: 04 April 2003

Peter Rathsman
Project Manager
Sweedish Space Corporation

SMART-1 Media Day
3rd April 2003
ESA/ESTEC

Published: 04 April 2003

Sven Grahn
VP Engineering
Swedish Space Corporation

SMART-1 Media Day
3rd April 2003
ESA/ESTEC

Published: 04 April 2003
The Next Generation Space Telescope (NGST) follows the highly successful Hubble Space Telescope (HST) with a scheduled launch late in this decade. NGST will be larger and more powerful than Hubble. The primary mirror will be 8 metres in diameter and capable of gathering ten times more light than Hubble. NGST will be launched into a special orbit that will keep it 1.5 million km from Earth (four times the distance to the Moon). By remaining in the shadow cast by a huge sunshield, NGST and its instruments will gradually cool to -240°C, giving the telescope an extraordinary sensitivity over a wide range of wavelengths in the infrared region of the spectrum.
Published: 01 January 2001
SMART-1 is the first of the Small Missions for Advanced Research in Technology of the ESA Horizons 2000 scientific programme. The SMART-1 mission is dedicated to testing of new technologies for future cornerstone missions, using Solar-Electric Primary Propulsion (SEPP) in Deep Space. The chosen mission planetary target is the Moon. The target orbit will be polar with the pericentre close to the South-Pole. The pericentre altitude lies between 300 and 2000km, while the apocentre will extend to about 10,000km. During the cruise phase, before reaching the Moon, the spacecraft thrusting profile allows extended periods for cruise science. The SMART-1 spacecraft will be launched in the spring of 2003 as an auxiliary passenger on an Ariane 5 and placed into a Geostationary Transfer Orbit (GTO). The expected launch mass is about 370kg, including 19kg of payload. The selected type of SEPP is a Hall-effect thruster called PPS-1350. The thruster is used to spiral out of the GTO and for all orbit maneuvers including lunar capture and descent. The trajectory has been optimised by inserting coast arcs and the presence of the Moon's gravitational field is exploited in multiple weak gravity assists. The Development Phase started in October 1999 and is expected to be concluded by a Flight Acceptance Review in January 2003. The short development time for this high technology spacecraft requires a concerted effort by industry, science institutes and ESA centres. This paper describes the mission and the project development status both from a technical and programmatic standpoint.
Published: 01 December 2002
Presentation from the press event marking the beginning of Cluster's operational phase - held at ESA HQ, 16 February 2001.
Published: 16 February 2001
Presentation from the press event marking the beginning of Cluster's operational phase - held at ESA HQ, 16 February 2001.
Published: 16 February 2001
23-Nov-2020 16:42 UT

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