The four-spacecraft Cluster mission of the European Space Agency (ESA) was intended to study microphysical plasma processes especially at magnetospheric boundaries, as a component of the overall International Solar-Terrestrial Physics (ISTP) program. Unfortunately, it was lost because of a launch failure on June 4, 1996. ESA now expects to launch a replacement set of four spacecraft (two in June 2000 and two a month later) called Cluster II.
Ramona Kessel of the Space Science Data Operations Office (SSDOO) attended a Cluster II Plasma Electron and Current Experiment (PEACE) team meeting held at Mullard Space Science Laboratory (Holmbury St. Mary, England) on January 29-30, 1998. Among the topics for discussion were the dissemination and archiving of the new Cluster II data.
The old Cluster Science Data System (CSDS)-User Interface (UI), provided by ESA for viewing and working with Prime and Summary Parameter data (selected, definitive physical parameters at 4-sec and 1-min resolution, respectively) and for exchanging data between data centers, is not going to be used for Cluster II. ESA has minimal funds for such tools. However, CSDS-UI may be replaced by either a Web-based version, now in the final stages of development, or by a new Web-based system proposed by (among others) Rutherford-Appleton Laboratory (RAL) and Queen Mary and Westfield College (QMW) of England. (See their Web-based data base.) The new system will be chosen soon and called CDMS. It will be maintained by the Joint Science Operations Center (JSOC) located at RAL, an ESA-funded group whose primary function is the coordination of the commanding of the Cluster payload.
It is proposed that in the U.S. the Prime and Summary Parameter data will be made available through the CDAWeb system, built and supported by the Space Physics Data Facility (SPDF) and NSSDC. The Summary Parameters, from just one spacecraft, will be publicly available immediately, while the Prime Parameters, from each of the four spacecraft, will initially be available to the U.S. co-investigators or guest investigators and will at some time in the future become publicly available.
There was also discussion on making some kind of summary data immediately available most likely via the World Wide Web (WWW). There is an inherent delay associated with data validation activities in the current plan for the production of the Prime and Summary Parameter data. Recent experiences have shown the usefulness and public impact of having near real time data available (e.g., the recent magnetic clouds hitting Earth and viewed by ISTP satellites and ground-based receivers).
The Cluster Archiving Task Group recently received a mandate from the Cluster Science Working Team. Members include Andrew Fazakerley, Mike Hapgood, Chris Harvey, Wolfgang Baumjohann, and Tony Allen. The mandate reads, "Identify and explore issues associated with the long-term preservation, accessibility, and exploitation of data from the Cluster mission, recommend to the SWT a Cluster archiving policy, and, with the PIs, develop an implementation plan."
The Cluster spacecraft launches will use the (highly reliable) Soyuz booster with a (presently unqualified) Fregat upper stage, both provided by the STARSEM company, whose shareholders are Arianespace, Aerospatiale from France, and RKA and Samara Space Centre from Russia. Fregat is expected to be used to launch Russian payloads (GLONASS satellites) prior to Cluster. The Cluster launch site is Baikonur Space Centre, Republic of Kazakhstan.
An artist's rendition of the Cluster satellites.
A book will shortly be published by ESA under the title Analysis Methods for Multispacecraft Data. It was produced under the auspices of the International Space Science Institute and should provide useful information for all interested in Cluster science.
Erin D. Gardner, firstname.lastname@example.org, (301) 286-0163
Raytheon STX, Code 633, NASA Goddard Space Flight Center
Greenbelt, MD 20771, U.S.A.