1. Purpose

This data policy describes the principle of handling data when the Institute of Space and Astronautical Science (ISAS) carries out its own scientific research and development in the field of space science.

2. Application

This policy applies to data obtained or processed by ISAS. Furthermore, for data taken or processed by other parties (e.g., Japanese universities, foreign institutes, etc.), where ISAS provided the required instruments, launch opportunities, budget, human resources, etc., we hope the philosophy of this data policy be respected by those parties.

3. Scope of the data where this data policy to be applied

We define the scope of the "data" covered by this policy as follows: information having broad scientific value, that is universal and long-term, and is independent of the storage medium.
The following are examples of what is not included in the current scope of the "data"; personal notes or photos, informal reports, memos and minutes of meetings, temporary information not intended for long-term use, physical samples from celestial bodies (such as asteroids) or the samples used by micro-gravity experiments.

Here are several representative (but not comprehensive) examples of data in the current scope with a brief explanation of each example:

  • Source data/Raw data: For example, satellite telemetry which may have to be parsed according to specific formats and will be the source of all following data processing. After the proper data processing, "Observation data" and "Engineering data" (see below) can be produced.
  • Observation data: Collections of numerical values taken by artificial satellites, space probes, balloons, sounding rockets, etc., that describe physical conditions of celestial bodies or space phenomena that cannot be controlled by observers. Many space phenomena show significant time variations, so that observational data may not be reproducible.
  • Engineering data: Collections of numerical values of physical conditions, orbits, attitudes, temperature etc. pertaining to the instrument (satellites, space probes, instruments etc.).
  • Experimental data: Collections of numerical values obtained by intentionally controlling objects by the observer. In most cases, identical or similar results can be reproduced by repeating the same experiments.
  • Simulation data: Collections of numerical values artificially produced by computation in order to simulate observation data, engineering data, experimental data etc. By repeating the computations, identical simulation data can be reproduced, in principle.
  • Collections of values resulting from analysis of physical samples, numerical values that reproduce the shape of the observed celestial bodies (shape-model), etc. These data may be updated when accuracy of the analysis or reproduction is improved.
  • Digitized documents, photos, pictures, videos, etc., which are created with the aim of long-term and universal use.

In addition, we consider the followings entities as data covered by the present data policy; data to describe the data (meta-data), tools and software required to use the data, algorithms used to create the data, descriptive documents about the data.

4. Undisclosed data and open data

All data have to be either "open (public)" or "undisclosed (proprietary)". We will judge if each type of data will be open or undisclosed, considering individual circumstances.
Those data which will be evidence of published scientific results shall be disclosed. Generally, most of data are open to public, except when

  • it may cause harm for public security or privacy if made open,
  • it may have scientific demerits if made open (for instance, calibration is uncertain) *,
  • the data are used exclusively by the team who created data for a certain period of time, and
  • the data-right is granted to particular people or parties for a certain period of time.

In principle, we will indicate the presence of proprietary data along with the reasons why they cannot be opened. Exceptions to this will only occur when not clarifying the presence of proprietary data has specific merit.

For proprietary data, we define and indicate who can access the data and the proprietary period. When the proprietary period is over, the data may become public, continue to be proprietary, or be discarded.
For observation data collected by satellites, space probes, balloons, and sounding rockets etc., if a proprietary period is required for the instrument team to calibrate the instruments, or for the proposers/observers to use the data exclusively, the nominal proprietary period is one year after the data was taken.

* Even when calibration is insufficient, observation data may be opened in order to demonstrate initial performance of the instruments, explicitly indicating that the accuracy is not guaranteed. If observation data may not be open because of such calibration issues, the schedule for resolving the problem and opening the data must be provided.

5. Policy of open data

Based on the belief that global and long-term use of the open data will contribute to the progress of science, we will carry out the following measures:

  • Carry out proper data processing and provide reasonable data explanation, so that using the open data does not require any proprietary knowledge.
  • Open data will be kept at least 30 years ** in a usable condition.
  • Free services to easily find open data and enhance usability of the data will be provided.
  • Open data will be made citable using, e.g., Digital Object Identifier (DOI).

** This corresponds to the period when the data are considered to hold scientific values.

6. Rules when using the open data

When using open data, we request users to follow the rules below *** :

  • In principle, open data can be used free of charge, either for commercial or non-commercial purposes. They may be copied, forwarded or modified. However, for some open data kept at ISAS, third parties who are involved in the data production may impose other restrictions (for example, in instances when a third party shares the copyright).
  • When using data, please indicate origin of the data as "ISAS/JAXA". Further, if the third parties contributed to the data production request additional acknowledgments, data users are expected to follow those requests as well.
  • When the data are modified, please indicate the fact that the data were modified, and describe what kind of modification was made.
  • We are not responsible for the actions of data-users.

*** These rules follow Government of Japan Standard Terms of Use (Version 2.0)
and are compatible with Creative Commons BY 4.0

7. Preservation of data

In principle, we try to keep all data for as long as possible. However, considering costs and resources, we may have to discard data in some cases. The following are the guideline to preserve/discard data:

  • Public data will be kept for a long term period of no less than 30 years.
  • Those data which cannot be in principle be reproduced will also be kept for the long term.
  • Source data (raw data) from which other kinds of data can be produced will be kept for the long term in a condition that permits reprocessing.
  • Those data which can be in principle reproduced but which would require a large amount of resources to do so, will not be discarded if possible.
  • Those data which can be easily reproduced may be discarded.