About

What is MetaSat?

MetaSat is open, collaboratively developed metadata that anyone can use to document small satellite missions.

Written in JSON-LD, MetaSat will initially be piloted by the Libre Space Foundation on their platform SatNOGS. NASA’s Small Spacecraft Systems Virtual Institute will also be collaborating with us moving forward.

Use cases

Click through for examples of what a filled out JSON-LD file using MetaSat could look like.

Observation: Scheduling an observation through a ground station network (e.g., SatNOGS). This example is an observation from a SatNOGS ground station of TECHSAT 1B. Notice that this example uses a trimmed down context, and does not include many spacecraft terms.

Space Segment: Describing a space mission and associated spacecraft.

Ground Segment: Describing a ground station and other ground-based components.

Context file

We’ve included an example of the @context section that helps give JSON-LD its structure and can turn your data into linked data. Our context file is based on the JSON-LD recommended context, with a few additions. Please keep in mind that this is simply a jumping-off point, and is meant to inspire, not constrain.

When using this example context, and in our example files, most keys will map to “https://example.org/[key].” The rest are Compact URIs, or CURIEs. A CURIE uses the aliases in the context to help make keys shorter. For example, our context file includes the line “schema”: “https://schema.org/”. If you wanted a key to map to https://schema.org/Person, you could use the CURIE “schema:Person.” The alias comes first, then a colon, and then whatever comes after the delimiter in the URI (in this case, the forward slash).

How to use JSON-LD

JSON-LD (JSON for Linked Data) is more than just a data exchange syntax. The JSON-LD specification also includes a set of transforming algorithms help you create linked data that is easy for machines to use and easy for humans to read and write.

Linked Data

JSON-LD is one of several W3C-recommended implementations of the Resource Description Framework (RDF), making it ideal to create linked data. Linking data makes data and information more accessible to both machines and people. It can help simplify knowledge management, or even help search engines find information more efficiently. Google already uses JSON-LD and linked data: if you Google something like the name of a famous celebrity, the distance to the sun, or the capital of Nepal, you might see a box with information on the subject before you even get to any links. These are called “knowledge panels,” and they are created using the magic of JSON-LD and linked data!

That being said, you don’t need to know anything about W3C, RDF, or the semantic web to take advantage of JSON-LD and linked data!