Secondary Payloads Increasingly Take Center Stage

CubeSats (Credit: ESA/Medialab)

by Douglas Messier
Managing Editor

On most launches, the small secondary satellites that ride along with the primary payloads garner little attention.

That has begun to change in recent years as CubeSats have become increasingly capable. The importance of these small satellites could be seen in the recent launch of an Indian PSLV rocket, which carried a CartoSat Earth observation satellite and 30 secondary spacecraft from India, Canada, Finland, France, Republic of Korea, UK and the United States.

The table below shows the manifest for the PSLV C-40 flight.

Cartosat 2 (Primary)1ISROIndiaEarth observation
MicroSat-TD1ISROIndiaMiniature multispectral technology demonstration payload
INS-1C1ISROIndiaTechnology demonstrator
 Arkyd 61Planetary ResourcesUSADemonstration of core technologies for use in asteroid exploration
CICERO 71GeoOpticsUSACommunity Initiative for Cellular Earth Remote Observation (CICERO) 7 will measure global weather patterns with high accuracy using a GPS radio occultation sensor
Landmapper-BC31AstroDigitalUSAMulti-spectral remote sensing spacecraft that is part of a 10-satellite constellation
Flock-3P4PlanetUSAEarth observation
Lemur 2y4SpireUSAAutomatic identification system (AIS) for vessel monitoring and operational meteorology
MicroMAS-31MIT Lincoln Laboratory, MIT  Space Systems Laboratory & University of Massachusetts at Amherst; funding from U.S. Air Force & NOAAUSAMicro-sized Microwave Atmospheric Satellite will conduct radiometer measurements
Fox 1D1Radio Amateur Satellite Corporation (AMSAT)USAAmateur radio communications
Tyvak1TyvakUSAAstronomical satellite will catalog variability of luminous stars
DemoSat 21UnknownUSAUHF radio test
SpaceBEE4UnknownUSA2-way satellite communications and data relay
LEO Vantage 11Telesat CanadaCanadaKa-band communication satellite demonstration for 120-spacecraft low-latency communications constellation
Carbonite-21Earth-iUKEarth observation technology demonstration mission to test and validate a high-definition imagery and video system for constellation
ICEYE X11ICEYEFinlandSynthetic aperture radar proof of concept for SAR constellation
PicSat1LESIA (Laboratoire d’Etudes Spatiales et d’Instrumentation), Observatoire de Paris, 3 universitiesFranceAstronomical satellite for the measurement of exoplanet transits
CANYVAL-X 1Yonsei University, Korea Aerospace Research Institute (KARI) & NASA Goddard Space Flight CenterSouth KoreaAstronomical satellite
CNUSail 1 (Papillon)1Chungnam National UniversitySouth KoreaSolar sail demonstrator
KAUSAT-51Korea Aviation UniversitySouth KoreaInfrared Earth imaging
SIGMA1Kyung Hee UniversitySouth KoreaGlobal magnetic field research
STEP Cube Lab1Chosen UniversitySouth KoreaDemonstration of thruster, radiator and heat pipe technologies

Planet and Spire, two companies that have built their business models around CubeSats, each had four spacecraft aboard the booster. Planet’s large constellation of satellites image the entire planet on a daily basis. Spire’s Lemur spacecraft provide ship tracking and operational meteorology services.

Telesat Satellite Internet

Telesat’s Phase 1 LEO spacecraft, built by England’s Surrey Satellite, is the first of a planned constellation of 120 satellites designed to provide fiber-like broadband Internet services anywhere in the world.

“The company’s Phase 1 testing will demonstrate key features of Telesat’s LEO system design, in particular the capability of the satellite and customer terminals to deliver a low-latency broadband experience that MEO and GEO satellites cannot provide,” the Canadian company said in a press release.

“Telesat has installed ground infrastructure at its teleport in Allan Park in Canada to support testing and has customers in growing enterprise segments who will be participating in trials during 2018,” the company added.

Planetary Resources

Arkyd-6 spacecraft (Credit: Planetary Resources)

Planetary Resources Arkyd-6 CubeSat will test 17 elements the asteroid mining company needs to identify promising targets. The spacecraft’s most important instrument is  a mid-wave infrared (MWIR) imager that will provide pixel-level data of objects on Earth and in space.

“If all of the experimental systems operate successfully, Planetary Resources intends to use the Arkyd-6 satellite to capture MWIR images of targets on Earth’s surface, including agricultural land, resource exploration regions, and infrastructure for mining and energy,” said Chris Vorhees, chief engineer of Planetary Resources.

“In addition, we will also have the opportunity to perform specific celestial observations from our vantage point in low Earth orbit,” he added. “Lessons learned from Arkyd-6 will inform the company’s approach as it builds on this technology to enable the scientific and economic evaluation of asteroids during its future Space Resource Exploration Mission.”


The ICEYE-X1 spacecraft is the first microsat equipped to fly with synthetic-aperture radar (SAR) as well as the first commercial satellite from Finland.

“ICEYE has been committed to enabling better decision making for everyone with Earth observation capabilities, and now through this new SAR data source, we are closer than ever to unlocking that potential across many different industries,” said ICEYE CEO and Co-founder Rafal Modrzewski.

ICEYE says the data can be used for a number of applications, including monitoring changing sea ice, tracking marine oil spills and preventing illegal fishing. 


CARBONITE-2 (Credit: Earth-i)

Earth-i launched a Surrey Satellite-built prototype for its Vivid-i constellation, which will provide full-color, utlra-high definition video from orbit. The constellation will provide:

  • high-frame rate images with resolutions better than one meter for any location on Earth;
  • the ability to film moving objects such as surface vehicles, vessels and aircraft in ultra-high definition color video;
  • the capability to revisit the same location multiple times per day with agile satellites that can be pointed to image specific areas of interest; and,
  • the rapid tasking of satellites to take images or video, and fast data download within minutes of acquisition.

“Today is a significant milestone for Earth-i and for the global space industry,” said Earth-i CEO Richard Blain. “It’s the culmination of much hard work by the teams at Earth-i and SSTL. We are now researching and testing the technology and data services for the Vivid-i Constellation using the still and video imagery from this prototype – and showing our customers what will be possible in the future from new capabilities such as color video from space.”


AstroDigital’s Landmapper-BC spacecraft is the third of a planned 10-satellite constellation that will provide broad coverage multi-spectral imaging of the Earth. These spacecraft will complement a constellation of 20 Landmapper-HD satellites that will return high-definition imagery.

The company’s satellites will image all agricultural land on a daily basis to create deep stacks of pixels that can be used for trend detection and change identification.


GeoOptics’ CICERO 7 spacecraft is the seventh of a planned constellation of 24 satellites that will measure global weather patterns with high accuracy using GPS radio occultation sensors. The satellites observe how GPS signals refract as they pass through the atmosphere, allowing for the measurement of atmospheric pressure, temperature, moisture and the distribution of electrons in the ionosphere.

CNUSail-1 satellite [Credit: Chungnam National University]
In September 2016, NOAA awarded a weather data purchase contract to GeoOptics under a pilot program to evaluate how commercial satellites can help improve forecasting.

South Korean Solar Sail

Chungnam National University’s 3U CNUSail 1 satellite, also known as Papillon, will deploy a solar sail to demonstrate how it can be used to de-orbit a spacecraft.

The ultra-thin solar sail will be deployed using four steel beams measuring 1.42 meters (4.65 feet) in length.  The spacecraft’s orbital lifetime is expected to be three months.