Small Satellites – Key Terms You Should Know

2018-02-02T11:52:43+00:00 January 31, 2018|

Small satellites have disrupted the landscape of space exploration. Compared with traditional large satellites, they offer lower cost, quicker, more frequent and broader access to space.

Most are used for earth observation but others are used for communications, meteorology, research and insurance. The small satellite market is booming and recent launches have seen over 80 small satellites launched via a single rocket. Thousands of small satellite launches are planned over the next ten years and each one will require high efficiency solar to power them.

We’ve created a list of some important industry terms to help you get up to speed on this exciting and growing field… 

Satellite Types

SmallSats – Small satellites that are lighter and smaller than traditional satellites, weighing less than 500kg. Typically the size of small refrigerator but may be as small as a shoebox. Also includes nanosats, cubesats, microsats and minisats.

CubeSats – Small satellites with a standard size and form factor, also called U-class spacecraft. Made up of standard units (1Unit= 10x10x10 cm). Using commercial off the shelf components they were originally developed by academia in order to research space exploration.  Due to their cost-effectiveness, their use has now expanded to government and private sector projects. Alta solar is working with Twiggs Space Lab/Nearspace and Oresat on cubesat projects.

Nanosatellites – Small satellites weighing between 1kg and 10kg.

Picosatellites – Small satellites weighing less than 1kg. Satellite/Spacecraft Characteristics

BOL (Beginning of Life) – The state of a satellite or spacecraft upon launch and deployment. All systems, including solar cells are operating at their best.

EOL (End-of-Life) – The state of a satellite or spacecraft at completion of the intended mission duration. Factors limiting mission duration can be degradation of subsystems (e.g. solar cells) or the exhaustion of propellant needed to maintain orientation. A typical nanosat may only last a few years.

C-Band – The frequency used for many satellite communications (ranges from 4 to 8 GHz).

SEP (Solar Electric Propulsion) – The combination of solar cells and ion drive (a form of electric propulsion) used for propelling a spacecraft through outer space or even adjusting orbit. Many ion thrusters use Xenon gas as a propellant.

Space Conditions

Air Mass 1.5 (AM1.5) –  The air mass coefficient used for all standardized testing of terrestrial solar. It is a good representation of the solar spectrum at mid-latitudes where most of the world’s population live.

Air Mass Zero (AM0) – The air mass coefficient used for characterizing the solar spectrum in space.

HIHT (High Intensities and High Temperatures) – A space environment with operating temperatures above 200 degrees Celsius. This would be relevant on some missions to the inner planets such as Venus or Mercury.

LILT (Low Intensities and Low Temperatures) – Refers to space environments such as in deep space where solar panel temperatures can be as low as -80C or lower (-140C near Jupiter).

GEO/GSO (Geostationary or Geosynchronous Earth Orbit) – An orbit around the Earth where a satellite is positioned directly over the equator and at an altitude of 36,000 km and orbits at the same speed and direction as the Earth. This causes the satellite to appear in a fixed position in the sky.

LEO (Low Earth Orbit) – An orbit around Earth that is approximately 2000 km in altitude. The majority of satellites and spacecraft currently in orbit were launched into LEO. Due to their low altitude, they offer smaller fields of view compared with GEO.

Constellation- Multiple satellites that are launched into orbit and synchronized to overlap in coverage. This makes it possible to  achieve continuous geographic coverage (even with low earth orbits).


Regulations and Regulatory Bodies

FCC (Federal Communications Commission) – An agency of the US government that regulates the allocation of radio frequencies to radio, television, satellite, and cable. The FCC coordinates with other agencies via the ITU at an international level to ensure radio transmissions do not interfere with each other.

ITU (International Telecommunications Union) – An international agency (part of the United Nations) that is responsible for issues concerning information and communication technologies in areas ranging from internet access to radio astronomy and satellite-based meteorology. They also promote international cooperation by assigning satellite orbits.