A pair of nanosatellites called “Nodes” has been delivered to the international space station for deployment.

These two little pioneers, only a bit larger than soda cans, are out to demonstrate mesh communications capabilities. That means they will talk between themselves, passing data to negotiate which will be the link to earth at any particular moment based on which has the best shot at the connection.

The two satellites will also be monitoring the charged particle flux in their immediate vicinities and linking that to the ground. Each day they will autonomously decide which satellite will be the ground link master. All while in a 250-mile orbit.

The Nodes' major task tests. EPISEM refers to the science payload Energetic Particle Integrating Space Environment Monitor. (Image courtesy of NASA.)

These cubesats are Android-based and derivative of the pioneering phonesats launched by NASA a few years ago.

Paving the Way for Small Satellites

The Nodes weigh in at about 2 kilograms and are expected to last at least two weeks but they could well last more than six months. Each Node has three radios: a UHF beacon that transmits health information, another UHF radio for inter-satellite communications and an S-band radio for up/down linking.

After the units are placed in orbit they will start to separate and are expected to drift to more than 60 miles apart within a few weeks, making their UHF intercommunications harder and harder to achieve. This offers an ever-changing test of the satellites’ autonomous negotiations over which one will be the downlink node of the day.

NASA's Nodes. (Image courtesy of NASA.)

The original phonesats ran on batteries until dead. However, the Nodes have solar charging for better duration. The Nodes are the predecessors of the coming Edison Demonstration of Smallsat Networks (EDSN) which will be a swarm of 8 satellites flying in formation.

This interesting test will hopefully further the smallsat capabilities that come at low on-orbit cost. Cubesats like these tend to cost less than ten thousand dollars and hitch-hike to space using some of the excess lift capacity often available on launch vehicles.

Future Cubesat Applications

The Nodes are funded by the NASA's Small Spacecraft Technology Program (SSTP) which aims to use off-the-shelf technology to pull off cost-effective science. Once the communications issues are debugged with the Nodes and the EDSN mission, there are a host of future uses for cubsats.

These include setting up synthetic aperture radar for high resolution earth studies, studying Earth's magnetosphere in a distributed simultaneous manner, gravity field studies, some Earth-Sun interactions or even a long baseline telescope composed of a large swarm of distributed observers.

For more information, visit the NASA website.