The InnoSat spacecraft is based on a small, capable and low cost platform intended for a range of missions in Low Earth Orbit. It is designed to fit within a piggyback launch envelope that is roughly 50 kg mass and about 60x70x85 cm size, and to provide high performances in terms of pointing, power and data downlink. The need for routine engineering maintenance and support will be limited thanks to the high level of autonomy in the system.

The key performance factors of the InnoSat spacecraft standard bus is summarized in the table below. Should higher power be needed, the design supports two deployable additional solar panels.

Satellite mass <50 kg
Size 70x65x85 cm
Max payload mass Up to 15 kg
Max payload power 40 W (orbit average, 06:00/18:00 LTAN SSO),
extendable up to 120 W if required
Design lifetime 2 years
Downlink bitrate 3-5 Mbps
Pointing performance
Max 0.1 deg absolute pointing error
Max 0.01 deg pointing knowledge error (reconstructed)
Orbit determination On-board GPS
Nominal attitude mode Nadir/Forward-looking

The Prisma platform is a versatile small satellite platform that can accommodate a payload external to the main bus so as to be flexible to the payload dimensions and minimising need of redesign between various payloads. It has a high level of agility yet it can provide the pointing and stability required by e.g. high resolution imagery payloads. Integrated propulsion allows for orbit maintenance and potential de-orbiting. The platform builds on the PRISMA mission flight heritage, with regard to all subsystems.

Performance and design

Mechanical architecture
Prismatic box structure that can be sized. Payload can be mounted as assembly on upper deck or distributed over platform. Payload volume with max footprint approximately 1m x 1m, with height of 1 m.

Thermal control
Passive, with structure walls acting as radiators. Heat pipes if required.

Mechanisms and deployment
SA panel deploy mechanism, can be used for other appendages.

HYD or HPGP system for initial orbit correction, orbit maintenance and de-orbit. 2-8 thrusters in basic configuration.Up to 17.4 kg propellant in one tank.

Attitude and orbit control
Three-axis stabilized attitude. Use of reaction wheels as sole actuator in normal mode. Use of star tracker as primary sensor in normal mode. Roll and pitch manoeuvres supported by angular rate sensors. Sun sensor and sun presence detectors for Safe mode control. Wheels unloading by magnetorquers.

AOCS sampling frequency 10 Hz
Pointing accuracy = 17 mdeg (3)
Pointing knowledge = 15 mdeg (3)
Pointing stability (0,3 ms) = 0.08 arcsec
Pointing stability (2 s) = 2,3 mdeg (3)
Agility = 40 deg in 42 sec (including settling time)

Data handling
On-Board Management Unit based on LEON 3 FT processor. CAN bus, Spacewire and RS422 serial links. Dedicated Payload Data Handling system is assumed.

RTOS using RTEMS software.

Electrical power
SA panels with triple-junction GaAs cells. Li-Ion battery. 28 V regulated bus. Centralized distribution and protection in Power Control and Distribution Unit. Max average payload power 150 W (baseline configuration, adaptations are possible) Peak payload power 220 W (baseline configuration, adaptations are possible)

Platform RF communications
16 kbps PM uplink in S Band. Up to 5 Mbps kbps BPSK or QPSK HK data downlink in S Band. Omnidirectional coverage.

Payload data handling and transmission (optional)
Input interface = LVDS, Spacewire
Input rate = 1,5 Gbit/s max
Storage = 96 Gbyte max
Downlink rate = 350 Mbit/s max
Downlink frequency = X band
Compression = Lossless and lossy
Encryption = AES

Payload Mass
< 100 kg RAMS

Reliability > 0.91 for 5 years
Redundancy concept: Single point failure free

The Small GEO is a product line of general-purpose small geostationary satellite platforms. This new modular and flexible platform addresses especially the telecommunication satellite market and is compatible with the majority of  commercial launchers

Small GEO is a small European geostationary platform being developed under OHB SE (Germany) lead management. OHB Sweden is a Core Team Partner in the Small GEO Telecom satellite programme and we are responsible for the attitude and orbit control and electrical propulsion subsystems.

Small GEO has been developed as an optimum platform for communications payloads. With its modular design however Small GEO also provides a cost-efficient basis for other applications such as earth observation or meteorology.

What sets the Small GEO platform apart is its modular structure. As a result the satellite can be fitted individually in accordance with the customer s specific requirements without any major modifications to the satellite bus, the advantages being that short integration times make it possible to react swiftly to new market needs and reduce costs. The relatively low complexity of the system ensures high reliability in tandem with reduced program risk.

Small GEO comes in two major configurations, “FAST” with a combination of chemical and electrical propulsion, and “FLEX” based on only electrical propulsion for both orbit transfer and station-keeping.

The SMART platform was developed by OHB Sweden (at the time the Space Systems division of SSC) for the ESA SMART-1 lunar mission. SMART-1 was launched in 2003 and ended its successful mission to the moon in 2006. The platform uses electrical propulsion for orbit control and has a flexible attitude control system, and large solar arrays. The platform is highly suitable for interplanetary missions and missions to geostationary orbit. The satellite platform dry mass is around 200 kg and can support a payload of around 100 kg and provide up to 2 kW payload power.

OHB Sweden is one of Europe’s leading propulsion suppliers. Our knowledge and experience cover the complete range of different propulsion systems; electric propulsion, liquid propulsion as well as cold gas propulsion. We are able to understand and define the propulsion system, from the very early project stage and throughout the development and operating phase.

For the European Space Agency’s successful pioneer mission to the Moon, the SMART-1 mission, OHB Sweden implemented the highly efficient propulsion technology. In the demanding SmallGEO telecom satellite product line, OHB Sweden is providing the electric propulsion subsystem.

To enable the most recent addition to the SmallGEO product line, the full EP Electra platform, an electric propulsion subsystem is mandatory as it provides both the orbit transfer and station-keeping abilities, resulting in a significant mass saving and consequently larger payload mass.
For the ESA Solar Orbiter mission, OHB Sweden provides the chemical propulsion subsystem together with Airbus DS.

In close relation with OHB Sweden’s mission analysis team, AOCS department and AIV team, we are able to understand and define mission system and AIV needs on the propulsion system in early project stages. Today OHB Sweden has experience of a number of types of propulsion systems; electric propulsion, liquid propulsion, cold gas propulsion development framework.

Our capabilities and skills cover a wide range of areas; specification, procurement, manufacturing of propulsion hardware, design, analysis routing, accommodation of tubing and propulsion system components, plume impingement, thermal hydraulic, spacecraft charging, control algorithms FMECA/FDIR safety analysis, in-house facilities, in-house tubing fitting and bracket manufacturing, titanium orbital welding, radiographic inspection, cleaning and cleanliness verification, subsystem integration and test, ground flight operations procedures, encompassed technologies, electric propulsion.

OHB Sweden develops satellite guidance, navigation and control systems for innovative space projects. Our engineers are committed to achieve the highest standards in meeting our customers’ expectations of successful space missions. With extensive experience in spinners, low cost- and high performance 3-axis control systems, sensor technologies and navigation strategies for Rendezvous and Formation Flying in space, OHB offers world leading technological innovative capabilities within AOCS.

Our development framework covers:

  • ECSS-compliant design and verification processes
  • mission analysis
  • specification and procurement of sensors and actuators
  • development of state of the art AOCS flight software
  • high-performance 3-axis attitude control guidance for orbit transfer and station keeping
  • advanced orbit control for formation flying and rendezvous
  • system level simulator development software
  • spacecraft system level testing
  • flight dynamics
  • subsystem integration and test operations.

In-house we also have the SATLAB software system test environment, covering real-time simulation environment, EM computers in-the-loop, CAN-bus in-the-loop, other H/W simulated towards CAN i/f. Additional H/W can be included for H/W in-the-loop testing, commanded with real operational software through the RAMSES mission control system, expandable for S/C system test with FM H/W.

RAMSES is a flexible and extendable new generation monitor and control system software, developed by OHB Sweden. The system can be applied on both satellite and sounding rocket missions and is designed to be used during the development, integration, validation, and operational phases, thereby significantly decreasing project costs.

OHB Sweden has, during the last 30 years been responsible for the development of control systems for all Swedish scientific satellites.

RAMSES (Rocket and Multi-Satellite EMCS Software) is a new generation monitor and control system SW. Its development is based on more than 30 years of experience of satellite and sounding rocket missions. RAMSES includes the core functionality of a mission control system and offers great advantages compared to other control systems available on the market. These advantages include using low cost HW platforms, easy adaptation and customization to different missions and an open network interface to easily integrate third-party software. The system can be applied on both satellite and sounding rocket missions and is designed to be used during the development, integration, validation, and operational phases, thereby significantly decreasing project costs.

RAMSES is designed for several types of spacecraft constellations; single satellite missions and multi-satellite missions as well as sounding rockets with one or several experiment modules. RAMSES was used in developing the Prisma satellite system, a formation flying and rendezvous mission that was launched in 2010. RAMSES is currently used to operate the Prisma satellites.

It has also been used in several other projects; the MASER microgravity rocket missions and the Telescience Support System flown on the ESA Foton-M3 mission. The system is easy to configure and provides for a fast and straightforward setup.

RAMSES uses the Microsoft Windows 7 platform and runs on ordinary office PC’s enabling a cost-effective system and setup with no recurrent hardware costs. Due to the open network interface, custom nodes using different platforms can seamlessly be integrated into the system.

Using the same system in both test and operations brings several advantages, such as the possibility to reuse the telemetry/telecommand database, configurations and documentation as well as test and operational procedures. It also reduces compatibility problems as the system configuration has been thoroughly tested before launch.