Nanosatellites for Earth observation are very small, low cost satellites typically weighing kilograms and with volumes of a few liters. NASA has a program called the CubeSat Launch initiative (CSLI) which provides opportunities for nanosatellites to fly inexpensively as auxiliary payloads on rockets supporting major missions. NASA's CubeSats are cube-shaped satellites 10cm x 10cm x 10cm with a volume of about a liter and weighing about 1.3 kilograms.
Three startup satellite companies have already started putting nanosatellite constellations in space, that promise to provide much more frequent revisits per day than existing satellites can provide and at a much lower cost.
In April 2013 Planet Labs launched two demonstration satellites, “Dove 1” and “Dove 2”. Planet Labs has already launched 72 cubesats and plans to launch a total 100 of the Earth observing satellites at an altitude of 400 km. The satellites will provide frequent snapshots of the planet at a resolution of about 5 m, allowing users to track changes such as traffic jams, deforestation, construction progress in close to real time.
Skybox Imaging, acquired by Google, has launched the SkySat-1 and SkySat-2 satellites (each larger than nanosatellites at about 100 kg) which are intended to capture sub-meter imagery and HD-video of any spot on earth, multiple times per day to provide timely high-resolution imagery, HD video, and analytics.
In November 2013 two nanosatellites, NanoSatisfi's ArduSat 1 and ArduSat X, supported by Kickstarter crowdfunding were placed in orbit from the International Space Station . NanoSatisfi has since been renamed. Spire Global Inc, has launched 4 out of more than 50 planned remote sensing cubesats into orbit at altitudes of 500–600 km. Spire's remote sensing satellites range from cubesat 1U to 3U and are built with Commercial Off-The-Shelf (COTS) components wherever possible to lower costs. The spacecraft carry multiple sensors including RF sensors that are not restricted by clouds, haze and night.
Spire's business niche is 80 km from any coastline, the three-quarters of the Earth that is either covered by water or considered remote and is not regularly monitored by today's remote-sensing satellites. Spire plans to be able to collect data from any point on Earth every hour.
Spire’s multi-sensor satellites provide a variety of data types such as Automatic Identification System (AIS) service for tracking ships, and weather payloads that measure temperature, pressure and precipitation. Spire plans for a 2 year refresh cycle on each satellite enabling a continual improvement in on-board technology .
Some of the applications Spire is targeting include;
- Illegal fishing - Monitoring illegal, under-reported and unregulated fishing.
- Trade monitoring - Virtually all global trade transits through areas of the planet otherwise ignored by traditional remote sensing. Spire can deliver reliable data on every ship in every ocean every hour.
- Marine domain awareness - Criminal activities such as illegal shipments and clandestine cargo exchange are some of the issues.
Other applications envisioned for the future include;
- Insurance - when ships collide determining what actually happened
- Environmental impact - in case of oil spills helping to determine who's liable
- Asset tracking - finding ships in distress faster
- Piracy - vessel tracking that cannot be disabled by pirates