Integrated Solar Array and Reflectarray Antenna (ISARA) - 10.25.17

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ISS Science for Everyone

Science Objectives for Everyone
Integrated Solar Array and Reflectarray Antenna (ISARA) prepares a new hybrid antenna and power system for space applications by demonstrating its use in CubeSat-based environmental monitoring. Advances in material science and electrical engineering have made possible a flexible solar panel that can send and receive messages. ISARA tests the performance of these new solar antennas in collecting instrumental data aboard a CubeSat deployed from the International Space Station and monitored by ground-based engineering crews.
Science Results for Everyone
Information Pending

The following content was provided by Richard Hodges, Ph.D., and is maintained in a database by the ISS Program Science Office.
Experiment Details


Principal Investigator(s)
Richard Hodges, Ph.D., CALTECH Jet Propulsion Laboratory, Pasadena, CA, United States

Daniel Hoppe, Ph.D., CALTECH Jet Propulsion Laboratory, Pasadena, CA, United States
Dorothy Lewis, M.S., CALTECH Jet Propulsion Laboratory, Pasadena, CA, United States

JPL, Pasadena, CA, United States
The Aerospace Corporation, El Segundo, CA, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
National Laboratory (NL)

Research Benefits
Scientific Discovery, Earth Benefits, Space Exploration

ISS Expedition Duration
September 2017 - February 2018

Expeditions Assigned

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • Integrated Solar Array and Reflectarray Antenna (ISARA) is a high-gain antenna (i.e., an antenna with a focused, narrow radio wave beam width) that provides an essential technology for high data rate communications. High data rates are key for Earth science instruments to deliver the science payload to researchers on the ground.
  • Antenna gain is proportional to antenna surface area. Therefore, to achieve high return, the antenna must be large. Nonetheless, the antenna must stow compactly and fit into the available CubeSat launch canister volume to deploy from the International Space Station (ISS).
  • Existing high-gain antenna technologies, such as parabolic reflectors, require a large percentage of the payload volume for stowage. This is not practical for small spacecraft such as a CubeSat because it does not leave room for the science instruments.
  • The ISARA reflectarray antenna concept folds into a thin, flat package that fits between the spacecraft and the launch canister, the area reserved for solar panel stowage. Therefore, the ISARA antenna uses essentially zero spacecraft volume.
  • Science instruments also require electrical power. ISARA demonstrates that the antenna can be integrated into specially designed solar panels so that the antenna also provides over 20 watts of spacecraft power.
  • The ISARA mission demonstrates for the first time that the flat panel reflectarray antenna concept works in space and that it can provide spacecraft power for a science instrument.
  • The ISARA spacecraft also demonstrates that the concept is viable by hosting a secondary payload called the CubeSat Multispectral Observation System (CUMULOS), which researches the use of commercial off-the-shelf (COTS) camera sensors to perform weather and environmental monitoring missions.
  • ISARA technology greatly expands the capability of CubeSats to perform science missions. In addition to the high data rate, the antenna technology can also be used to create sensors such as RADAR and Radiometers.


The Integrated Solar Array and Reflectarray Antenna (ISARA) mission demonstrates a reflectarray antenna that increases downlink data rates for CubeSats from the existing baseline rate of 9.6 kilobits per second (kbps) to more than 100 megabits per second (Mbps).
The reflectarray antenna consists of three panels, electrically tied together through hinges, which have an array of printed circuit board patches on them. The size of the patches is adjusted so that the phase of the reflected feed illumination collimates the radiation in much the same way a parabolic dish reflector would. Unlike a parabolic dish, however, the reflectarray panels are flat, which enables them to be folded down against the CubeSat. On the opposite side of the printed reflectarray antenna, solar cells have been added. This makes the overall antenna/solar array panel assembly slightly thicker, but the cells are stowed in the “dead space” between the launch rails that would have otherwise been left empty. This combination of antenna and solar cells makes for a very efficient use of CubeSat volume, leaving plenty of room for payloads such as science instruments or imaging systems.
The stowage volume and spacecraft power provided by ISARA technology also enables the ISARA mission to carry a secondary payload known as the CubeSat Multispectral Observation System (CUMULOS), an experimental Aerospace Corporation remote sensing payload. CUMULOS is composed of a 0.4-0.8 micrometer (μm) visible camera, a 0.9-1.7 μm short-wavelength infrared camera, and an 8.0-13.5 μm long-wavelength infrared, microbolometer camera.
The CUMULOS sensors provide a small-aperture, large field-of-view, remote sensing payload suitable for testing the performance of passively-cooled commercial sensors for weather and environmental monitoring missions. CUMULOS is designed for point-and-stare imaging and allows almost simultaneous three-band coverage of regions 230 x 180 kilometers (km) in size, at ground sample distances from 180 to 600 meters. Remote sensing applications to be investigated include: cloud cover detection, surface temperature measurement, hotspot detection (including fires, gas flares, and volcanic activity), and detection of nighttime lights.
The ISARA mission is validated in space during a five-month mission to measure key reflectarray antenna characteristics, which include how much power can actually be obtained over its field of view. ISARA contains a transmitter and an avionics subsystem that features a Global Positioning System (GPS) receiver and a high precision attitude control system designed to orient the CubeSat to enable accurate antenna beam pointing. Once in orbit, ISARA deploys its solar array and reflectarray antenna. It then uses its attitude determination and control system to stabilize itself. An ultra-high frequency (UHF) communications system is used to make initial contact with the satellite and perform in-orbit checkout procedures.
During the in-orbit test, ISARA’s reflectarray antenna transmits a signal that is received by a ground station located at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. The spacecraft’s location and orientation telemetry data is analyzed to reconstruct the antenna signal pattern, which then is compared against pre-flight ground measurements.
At the end of the validation mission, the reflectarray antenna technology is available for use on other missions that need high bandwidth telecommunications. The ISARA technology enables CubeSats and other small satellites to serve as viable platforms for performing missions that were previously only possible on larger and more costly satellites. For a modest increase in mass, volume and cost, the high data rate this technology enables, paves the way for high value science missions and formation flying missions that use distributed CubeSats and small satellites.
ISARA was selected for a flight opportunity as part of the CubeSat Launch Initiative in NASA’s Human Exploration and Operations Mission Directorate. ISARA’s spacecraft is launched and deployed as an auxiliary spacecraft on a rideshare mission arranged by the Launch Services Program at NASA’s Kennedy Space Center.
The ISARA mission is funded through NASA’s Small Spacecraft Technology Program (SSTP), which is chartered to develop and mature technologies to enhance and expand the capabilities of small spacecraft with a particular focus on communications, propulsion, pointing, power, and autonomous operations. SSTP is one of nine programs within NASA’s Space Technology Mission Directorate.

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Space Applications
ISARA serves space applications by demonstrating a light, flexible hybrid power and communication system. The growing range of landed and orbital missions to far-flung destinations in the solar system requires new technologies for powering instruments and sending data. ISARA is an agile solution that meets power and communications needs of distributed platforms like CubeSats or instruments sent to other planets.

Earth Applications
As a light, flexible hybrid power and communication system, ISARA has the potential to serve military, recreational and scientific applications on Earth. From remote outposts in war zones to Burning Man camps in the Nevada desert, solar-powered communication devices and instrumentation can save lives, collect data and enhance human connection.

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Operational Requirements and Protocols

NanoRacks CubeSats are delivered to the ISS already integrated within a NanoRacks CubeSat Deployer (NRCSD) or NanoRacks DoubleWide Deployer (NRDD). A crew member transfers each NRCSD/NRDD from the launch vehicle to the Japanese Experiment Module (JEM). Visual inspection for damage to each NRCSD is performed. When CubeSat deployment operations begin, the NRCSD/NRDDs are unpacked, mounted on the JAXA Multi-Purpose Experiment Platform (MPEP) and placed on the JEM airlock slide table for transfer outside the ISS. A crew member operates the JEM Remote Manipulating System (JRMS) – to grapple and position for deployment. CubeSats are deployed when JAXA ground controllers command a specific NRCSD.
Following deployment from the NCRSD, the ISARA spacecraft starts the operational phase of the mission. The key event is deployment of the ISARA solar panels. Once the panels are deployed and nominal operations are established, the experimental phase begins. This involves precision gain and antenna radiation pattern measurements performed using the Jet Propulsion Laboratory Ka-band ground station. This data is used to verify the successful operation of the antenna and demonstrate the capability to achieve 100 Mbps data rate. The CUMULOS secondary payload mission starts when the primary mission concludes.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Related Websites
Jet Propulsion Laboratory
More information about Small Spacecraft Technology (SSTP)
Small Satellites - Integrated Solar Array and Reflectarray Antenna (ISARA)

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