In this post we give a brief overview of how Earth Observation (EO) optical payloads are used in small satellites and share listings of multiple products available on the global marketplace - if you would like to skip the introductory material and instead get straight to the product listings, please click here.
Space engineers have been looking to lower costs by using commercial off-the-shelf (COTS) innovations for the last few decades.
Alongside this commercial drive, experiments into the use of COTS components and sub-systems have been carried out at universities such as the University of Surrey and TU Berlin for several years.
In fact, the foundation of experimental satellites built by universities, such as the UoSAT and TUBSAT series of satellites, has provided the basis for realising cost-effective spacecraft that are packed with decent Earth Observation (EO) capabilities.
It is worthwhile to note interesting observations made by Professor Sir Martin Sweeting (Figure 1) of improvements in performance criteria such as Ground Sampling Distance (GSD), data rate, data storage etc., having a very close association with Moore’s law.
One could argue that the cost of satellites themselves has possibly followed the same trajectory (given the same GSD) due to factors such as reliability of COTS electronics and the decrease in launch costs.
Figure 1 - Moore’s Law observed in small satellites (image credit: Professor Sir Martin Sweeting ).
A whole generation of universities and NewSpace companies have leveraged such cost-effective spacecraft development in the small satellite world and have taken advantage of the increase in computing capabilities to generate much greater progress in the last thirty years.
The invention of CubeSats led to further interest in COTS EO payloads by students and engineers and has also enabled the translation of academic research interests into the development of innovative NewSpace EO ventures.
The most well-known example of this is Planet Labs, which has flown over 200 satellites based on CubeSat standard.
Choosing the right optical payload for your mission
When selecting any piece of technology for your mission it is important to be aware of costs, lead times, integration and testing requirements, as well as the physical requirements of your system.
In addition, here are some of the key performance criteria to consider when assessing which payload is right for your needs:
- Spatial resolution - a measure of the smallest object that can be resolved by the optical payload.
- Spectral resolution - the number and width of spectral bands that the sensor can collect from reflected radiance.
- Swath - the area imaged by the optical payload.
- Radiometric resolution - this indicates how much information is in a pixel and is expressed in units of bits.
- SWaP factor - the size, weight and power of the satellite or sub-system.
Optical payloads on the global market
In the list below we have rounded up a range of commercially-available EO optical payloads for small satellites (<100 kg) on the global marketplace for space.
Please note that this list will be updated when new products are added to the global marketplace for space - so please check back for more or sign up for our mailing list to get all the updates.
The IM200 by Hyperion Technologies
The IM200 is a versatile imager, based on the ST200 Star Tracker platform. With a dedicated high-speed USB2.0 interface, the IM200 is capable of capturing 5 frames per second at full resolution. The large internal buffer allows for storing up to 25 full-frame images, which can be compressed into JPEGs for fast previewing. The CPU power allows for real-time processing of the images, allowing for the use of the IM200 as a target-tracking imager, a docking camera or an inspection camera. The small form factor and low mass makes the system highly flexible. The system also features flight heritage, for trusted performance during launch and in-orbit.
The iSIM portfolio of Satlantis Microsats
Satlantis manufactures a range of high-resolution EO cameras for microsatellites in the Integrated Standard Imager for Microsatellites (iSIM) portfolio. All systems feature a low mass and size to performance ratio and the range consists of:
iSIM-12U - the 6kg integrated Standard Imager for Microsatellites 12U is a high-resolution multispectral (RGB, NIR) camera specially designed for Earth Observation 12U CubeSats. It provides a low mass-to-performance ratio, for a fraction of the cost of many of today’s Earth Observation instruments. It has a GSD of <2m @ 500km, a swath of 13km @ 500km and operates with 4+1 (VNIR) multi-spectral bands.
iSIM 170 - the 15kg integrated Standard Imager for Microsatellites is a high-resolution multispectral (RGB, NIR) camera for Earth Observation microsatellites (50-100kg). It provides a low mass-to-performance ratio, for a fraction of the cost of many of today’s Earth Observation instruments. It has a GSD of <1m @ 500km, a swath of 7.5 km @ 500km and operates with 4+1 (VNIR) multi-spectral bands.
SWIRHOT - the Short-Wave InfraRed High-resolution Optical Technology is the latest development in the iSIM family. It is an innovative VNIR & SWIR camera that operates in the spectral range of 450-1450nm, taking full advantage of the iSIM-170 optomechanical design and requiring no cryogenic cooling system. It features a GSD of 2,2 m @ 1,2 µm with super-resolution and 5,0 m @ 1,2 µm without as well as a swath of 7.5 km @ 500 km.
The SEEING 1.5-m / 0.75-m and 10-m by Safran Reosc
Safran Reosc is developing high-performance imaging payloads for smallsats, building on the decades of experience in the development of high performance space optics, electronics and software of its parent company Safran Electronics & Defense assets.
These diffraction-limited EO payloads are designed for optimised SWaP factor (size, weight and power) in order to deliver the maximum additional value for the end-user at system level, thanks to many kgs of mass and litres of volume saved.
The two core products are:
The SEEING 1.5-m / 0.75-m - a high resolution payload suitable for fine Ground Sampling Distance (GSD) to 1.5-m from 500 km. It features a 10 x 7 km² wide FoV, 2D CCD/CMOS sensor and multi-hyperspectral capabilities. With 190 mm aperture it features only 8U volume and 6 kg weight as well as a super-resolution mode that offers sub-metre imagery.
The SEEING 10-m - a multi-hyperspectral payload with a 10-m resolution and a 60 x 40 km² wide FoV from 600 km orbit. The moderated GSD is balanced by low F/N of the optics enabling imagery and detection in low light level environment. The key target application is maritime awareness. The payload is fitted within 8U (plus entrance baffle) and weighs only 8 kg.
The portfolio of Simera Sense
Simera Sense manufactures a range of optical payloads for different application and system requirements. The portfolio is primarily designed for EO applications in CubeSats and consists of:
The HyperScape100 - a hyperspectral push-broom imager based on a 12.6-megapixel image sensor and continuously variable filter in the visible and near-infrared (VNIR) spectral range.
The MultiScape100 CIS - a multispectral push-broom imager based on a CMOS image sensor and a multispectral filter in the visible and near-infrared (VNIR) spectral range.
The TriScape100 - a colour snapshot imager based on a 12.6-megapixel CMOS image sensor with an integrated Red Green Blue (RGB) Bayer filter in the visible spectral range.
The optical payload portfolio of SCS Space
SCS Space manufactures a range of EO optical payload products:
The Chameleon camera - a high capacity, high-performance, mass storage EO camera designed for the CubeSat form factor.
The Gecko imager - an ultra-compact CubeSat imager that provides RGB matrix or multispectral linescan imaging, and features large, integrated, high-speed data storage.
The Monitor imager - multispectral imaging capability in a small package, using advanced detectors, optics and high-speed data capture designed to provide achievable ground resolution while maintaining high levels of swath, spectral performance, and ease of operation.
The Tegu imager - a lightweight multispectral imager with a 200mm aperture suitable for demanding microsatellite missions. Dynamic selection of spectral bands is enabled, covering Coastal, Blue, Green, Yellow, Red, Red Edge, NIR and PAN.
The Iguana imager - featuring high performance optics with a large square aperture. The control electronics offer on-board image processing and an integrated high speed buffer. The system is also compact enough to serve as the optical payload on a 16U CubeSat.
The High Resolution Video Camera (HRVI-6HD) and VNIR & SWIR Hyper Spectral Camera (HSI-100) by Berlin Space Technologies
The High Resolution Video Camera (HRVI-6HD) - interactive and real-time operation to support all mission types, including time-critical applications such as search and rescue or security. Featuring 240 GB of storage, a 5 year lifetime and a data rate of 1.4 Gb/s.
The VNIR & SWIR Hyper Spectral Camera (HSI-100) - a dual-band VNIR & SWIR hyper spectral payload built upon a proprietary technology from Singapore. A special filter element allows the camera to act as a polarizing Fourier transform hyper spectral camera (PolarFour™). The payload incorporates a high performance data processing unit (DPU) and data storage for each of the two bands.
STREEGO is a multispectral EO payload for small satellites. Its mass and volume are designed specifically to be suitable for the small satellite form factor. The unobscured Three Mirror Anastigmat (TMA) design maximizes MTF at high spatial frequencies. STREEGO offers multispectral imaging, with options for hyperspectral, enabling applications for small satellites previously possible only in large satellites such as the Sentinel-2 class satellites.
The 90mm Optical System and 230mm Optical System by SatByul
SatByul manufactures two EO optical systems:
The 90mm Optical System - developed as an Earth observation payload for a 6U CubeSat. It is capable of providing up to 5m resolution images at 400km orbit. It has a compact size, slightly larger than 2U, and can be integrated to any satellite platform.
The 230mm Optical System - designed as a payload for a 16U CubeSat platform. It is capable of in-orbit reconfigurable GSD up to 2.5m and spectral bands up to 12 bands at 50km swath. By offering collection and rapid revisit it can provide repeated images of large areas for the purpose of conducting automated change detection data.
Described as the first ever miniaturized hyperspectral imager with its own brain HyperScout is designed for nano-, micro- and larger satellites. The compact reflective telescope ensures optical quality in the VNIR range and an on-board data handling system enables real-time data processing; providing Level-2 generation capabilities on-board, reducing the amount of data to be downloaded and processed.
In larger satellites the wide swath, Level-2 real-time data processing functionality, and minimal impact at system level, makes the HyperScout attractive as an ancillary instrument for providing real-time phenomena information, either to a larger primary payload or to a ground control room. This enables smart operational planning for large payloads.
The C3D CubeSat Camera by XCAM
A space-qualified TRL 9 CubeSat camera system which has proven flight-heritage having flown on both of the UK Space Agency’s CubeSat missions with a 100% success rate. The C3D may be customised to cater for customers’ individual requirements. The system weighs 85 g and operates in a 400-650 nm spectral band. It has a 3-year lifetime and 1.3 MP image sensor.
The Micro Camera System by Crystalspace
The Crystalspace micro camera family is one of the smallest and most advanced series of satellite camera systems on the market. It is well-suited for densely packed satellites, from CubeSats (for taking pictures of the Earth) to large satellites (monitoring cameras). Under 600 metres per pixel ground resolution is achieved from low Earth orbit (600 km) using the basic version of the optics (44 x 34 degree field of view) and sensor (640 x 480 pixels).
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 Professor Sir Martin Sweeting, “The Role of Small Satellites in Earth Observation Services,” European Space Agency.