Section 3

Figure 3.1 shows the expected flow process leading to the accomplishment of an IACG campaign. The process is represented by a linear flow from left to right across the center of the figure. Oversight and guidance are accomplished by the associated IACG science working team. The process is a natural progression of activities extending from the mission software tools for orbit planning for the campaign through the science planning and operations, data acquisition and processing, and culminating in scientific workshops and publications.

The success of the scientific campaigns, coordinated by the IACG, will be facilitated by an "enabling" environment. Once in place, the enabling environment will remove a significant number of traditional barriers that have impeded correlative and collaborative space science research in the past. The enabling environment is composed of the following elements:

1. learning from the lessons of the past
2. science campaign planning systems
3. modern data storage and computer networks
4. mission-oriented theory and models, and
5. advanced analysis and visualization tools.

3.1 Lessons from the Past

The workshop began with a discussion of lessons learned from previous spacecraft campaigns: the Dynamics Explorers (DE), given by R. Hoffman; the International Sun-Earth Explorers (ISEE) and the Geostationary Earth Observing Satellite (GEOS), given by A. Pedersen; the Active Magnetospheric Particle Tracer Explorers (AMPTE), given by R. McEntire; and the Polar Region and Outer Magnetosphere International Study (PROMIS), given by E. Hones. These discussions are summarized here.

DE

The DE project planned and implemented an extensive and formal collaborative program which involved the two DE spacecraft, other spacecraft, and suborbital and ground facilities. The key to successful execution was to focus of the activities on a central element, in this case the Project Scientist's Office, which included the Project Scientist, the Science Operations Planners, and the Experiment Operations Coordinators. Thus there was a central place for final planning of operations and decisions. During the joint DE-1 and -2 operations period, two scientists worked as Science Operations Planners, and four engineers as Experiment Operations Coordinators.

Collaborations were of two kinds: either long-term--usually with other spacecraft--or short-term or intermittent, with individual facilities or short campaigns. The Science Operations Planners coordinated the development of operations timelines for the DE spacecraft using predict orbit information. For long-term collaborations, an informal letter of invitation was distributed widely requesting a brief letter response. Those responding then submitted a two-page form, requiring formal sponsorship from the Science Team, which asked for information on the scientific purpose of the investigation, the epoch, orbit configuration, details of operations, and identification of a contact person.

Lessons learned from the DE campaigns are:

1. to develop specific ground rules, including rules on data handling and sharing;
2. to formalize the procedures of collaboration to avoid losing control through private agreements and incomplete information exchange;
3. to identify a single entity with responsibility for approving a collaboration; and
4. to provide detailed information about the spacecraft, orbits, operations constraints, etc., at an early time.

   ISEE and GEOS

   With GEOS, real-time operations were difficult because of the requirement for investigators to be at the operations center. Some lessons learned were that:

   1. it takes a dedicated person, or persons, to carry out a successful coordinated campaign;
   2. it is very useful to have interdisciplinaryscientists;
   3. all collaborators should have access to all the data that is obtained in a campaign;
   4. summary plots should not be too compressed--they need to be readable to be useful; and
   5. it is important that the data analysis activities of such campaigns be given enthusiastic support by the funding agencies.

   ISEE was one of the last spacecraft not have a data reduction computer of its own; it used a mainframe at GSFC and data tapes were distributed by mail. It did however have a "data pool" tape, which contained a selection of key-parameter-like material and could be used to identify events. Data pool tapes were widely distributed. The ISEE instruments were a considerable improvement over previous designs, so the PI's tended to spend a lot of time understanding the data, and reducing and publishing new material of their own, before getting down to cooperative work. Work on the foreshock, the comet encounter, the tail excursion, and PROMIS produced collaborative results, and it may be that emphasis on collaboration might have produced less good collaborative work. However, it should be remembered that the first CDAW's occurred with ISEE data, and are thought by many to have been successful.

   Lessons learned by ISEE are that micro-management is not required to achieve collaborative work, key parameters data are useful, and getting people together is probably necessary to spark such work, even though it is expensive. PROMIS, even though organized by a few people, was successful, and would have been much easier with the more modern equipment available to WIND and POLAR.

   AMPTE

   The AMPTE mission of three spacecraft was designed from the beginning to be a single integrated program. A key feature was the science data center where all data was processed. There were only two Principal Investigators, which enabled decisions to be made quickly and easily. Each Science Working Team meeting was documented by copying all the presentations and distributing these to all the investigators. Lessons learned were:

   1. a unified approach works;
   2. it is difficult to orchestrate research activities and follow-through for busy researchers; (one unsuccessful campaign had good preparation and data but poor follow-up in publications).
   3. It is important to have an enabling environment: e.g., display tools, exchange media for data, networks for communication.

   PROMIS

   The PROMIS campaign during the spring of 1986 used an opportune array of then-existing spacecraft and ground facilities to assemble a 3-month body of data for studying global features of the solar- wind-magnetosphere system. During this period DE-1 had its apogee in the polar region for imaging the aurora, and ISEE-1 and -2 and AMPTE-IRM apogees were in the tail. VIKING provided images, and, with DE-1, provided plasma and field measurements in the polar regions. Data from SCATHA, IMP-8, and geosynchronous satellites were also available. The EISCAT, Sondestrom, and STARE radars, along with arrays of other ground instruments, provided ionospheric information. Additional tracking and data acquisition was arranged, and several volumes of quick-look data were produced and widely distributed.

   Three coordinated data analysis workshops (called CDAW-9) were held with five 12- to 24-hour time intervals during which one or more substorms were selected for concentrated analysis. These data have been cataloged and archived at the National Space Science Data Center. A large number of scientific papers have been and continue to be published.

   It has been suggested that the PROMIS data set could serve as a prelude to the IACG campaigns by advancing the understanding of global aspects of the solar-wind-magnetosphere interaction, and by increasing the experience of science teams in global studies.

   3.2 Science Campaign Planning Systems

   The Goddard Space Flight Center (GSFC) Science Planning and Operation Facility (SPOF) is a centralized facility available to IACG campaign science investigators. The SPOF functions include coordination of science planning for the U.S. solar-terrestrial science spacecraft as well as IMP-8, GOES, and LANL, and also will in the future involve ground-based and theory elements. SPOF uniquely combines spacecraft ephemeris and model software to predict intervals when the spacecraft are in advantageous positions for scientific studies and presents the results to the IACG Science Working Group teams for campaign planning.

   The Spacecraft Position Information Network (SPIN) system is a tool to visualize the orbit profile of every IACG mission on a PC display. This software has been developed by the Japanese Institute of Space and Astronautical Science (ISAS). The purpose of SPIN is to distribute the definitive and/or predictive orbit data of all IACG missions in order to facilitate efficient study of the possible mission coordination in each agency. IACG Working Group-3 has offered SPIN for use by individual IACG campaign participants.

   3.3 Modern Data Storage and Computer Networks

   Key advances in modern data storage and data dissemination technologies are becoming widespread and economically feasible just at the time when they can significantly contribute to the IACG solar-terrestrial science initiative. One such enabling capability is that of the Compact Disk Read Only Memory (CD-ROM), which permits large volumes of data to be conveniently and inexpensively stored in random access media and hence readily distributed to the appropriate campaign scientists.

   An organized program to collect and load IACG campaign processed data to CD-ROM's will allow an ease of access to data for participants, and also unprecedented speed and convenience for subsequent local analysis. When combined with the recommended IACG standards in the labeling and formatting of data, the analysis and visualization of multiple instrument data will be made dramatically easier with more productive results for the campaign scientists.

   Another key capability is in the combined power of the modern computer networks that increasingly link most IACG science participants with massive mission and archive data storage facilities. The networks enable speedy, direct dissemination of data from either individual investigators or projects or from central archives and distribution facilities. Mission facilities connected to networks allow much more flexible collection of data. They also support easy access to and dissemination of data not included on a given CD-ROM and can rapidly provide additional ancillary data as they become available.

   3.4 Mission-Oriented Theory and Models

   As distinct from pure theory, the goal of mission-oriented theory is to develop models and techniques to assist the experimentalists, data analysts, and theorists in interpreting the local satellite measurements so as to maximize scientific return from the missions.

   There are different types of mission oriented theory, such as magnetohydrodynamics (MHD), plasma kinetic simulations, and large-scale kinetics. Within the approximation of MHD, global simulations calculate the self-consistent electromagnetic fields produced by the interaction of the solar wind with the magnetosphere and predict the local values of the plasma parameters, which can be compared to satellite measurements. Although the MHD moments can be constructed from measurements, the particle distributions are often quite complicated, having multiple components and considerable fine structure, which the MHD calculations cannot describe.

   Kinetic plasma simulations on the other hand give a full description of the local plasma physics. This approach is particularly suited for studying local wave-particle interactions, but here the problem is that at present we are limited by computer capabilities to a very small spatial range. Plasma kinetic simulations on the spatial scale of the magnetosphere are beyond the realm of computational capabilities for the foreseeable future.

   The third method, large-scale kinetics, utilizes the global electromagnetic fields determined from MHD simulations and spacecraft observations and constructs the local kinetic plasma distribution functions by following single particle trajectories in a given field model. This technique of large-scale kinetics, which combines global MHD simulation, observationally constrained field models, and plasma kinetic simulations, provides a method for relating and coupling the locally measured plasma distributions and waves to large-scale magnetospheric structure and dynamics. The limitation of this method is that the computed plasma distributions are not necessarily self-consistent with the large-scale electromagnetic fields.

   There are also other modeling techniques, such as adiabatic-invariant-based diffusion descriptions and orbit-tracing approaches.

   Each of these different types of theory addresses different scales of processes and different levels of experimental detail. All will play an important role in relating theory and experiment within the context of an IACG scientific campaign.

   3.5 Advanced Analysis and Visualization Tools

   Much of the actual planning, operations, and data acquisition is carried out by the respective satellite and ground-based projects that are part of the IACG and STEP programs. Following data acquisition, each participating agency's project team will process and distribute key parameters for the designated campaign times. Included in this key parameter distribution will be information concerning the availability of high-resolution data during the designated times. The selection of candidate events for more detailed study will be based on this summary data set and will be carried out by the participating project principal investigators, ground-based experimenters, and other affiliated campaign participants.

   Workshops will be organized to discuss selected events. High-resolution data could be exchanged by PI's of relevant instruments of the IACG missions. Working Group-2 is responsible for providing an enabling environment to facilitate and encourage this exchange of data between investigators.

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