Minimize UKube-1

UKube-1 (United Kingdom Universal Bus Experiment 1)

UKube-1 is a pilot project of UKSA (United Kingdom Space Agency), announced in July 2010, to launch Britain's first CubeSat. The project will use a 3U CubeSat platform that is currently under development by the company Clyde Space Ltd. of Glasgow and will involve a competition amongst companies and academic groups to come up with the most innovative ideas for payloads. 1) 2) 3) 4) 5)

UKube-1 is a collaboration between the UK Space Agency, industry and academia. The funding partners for UKube-1 are the UK Space Agency, the Technology Strategy Board and STFC (Science and Technology Facilities Council). The spacecraft is being developed through a Knowledge Transfer Partnership with the Scottish company Clyde Space and the University of Strathclyde, supported with internal funding from Clyde Space. The UK’s largest space company, EADS Astrium Ltd, is providing engineering and program management support to the Agency for the pilot program. UK industry and academia are providing the payloads and the ground support operations. 6)

UKube-1 is the first mission of the newly formed UK Space Agency. The following five core mission objectives, the majority of which will be fulfilled before the Spacecraft reaches the launch pad.

1) UKube-1 shall demonstrate new UK space technology

2) UKube-1 shall demonstrate the capability of useful science to be performed within a CubeSat sized spacecraft

3) UKube-1 shall demonstrate industry and university university based training in spacecraft development

4) UKube-1 shall demonstrate education and outreach in STEM (Science, Technology, Engineering, Mathematics) subjects

5) UKube-1 shall demonstrate Payload Kick-Off to flight qualified spacecraft in < 12 months.

The requirements call for the support of at least 3 primary payloads. The UKube-1 project features 5 payloads.

The following institutions/companies/entities are involved in the development of UKube-1: UKSA, Bright Ascension, CSL (Clyde Space Ltd.), EADS Astrium Ltd., AMSAT UK, University of Strathclyde (Glasgow), Open University, University of Bath, UKSEDS, RALSpace, University of Dundee, Steepest Ascent Ltd., Glasgow, Cape Peninsula University of Technology (CPUT, Cape Town, South Africa), Commercial Space Technologies, SciSys, Knowledge Transfer Partnerships, Technology Strategy Board, Gomspace, ISIS [Innovative Solutions In Space BV (Delft, The Netherlands)], Pumpkin Inc. 7)

Some steps on the way to a project:

• In March 2011, 4 payloads were selected from 22 proposals

• As of July 2011 Clyde Space has accepted the role of Prime for the mission, with overall responsibility for the delivery of the complete mission.

• The CDR (Critical Design Review) of the mission took place on Nov. 3-4, 2011. 8)


Figure 1: Artiist's rendition of the UKube-1 nanosatellite in orbit (image credit: UKSA, ClydeSpace) 9)


The UKube-1 platform is being developed by Clyde Space and the University of Strathclyde. The UKube-1 features a 3U CubeSat form factor, a nanosatellite of size 10 cm x 10 cm x 34 cm and a mass of 5 kg. 10) 11)

The UKube-1 mission is broken into ten elements including the overall system design as given in Figure 2. Five areas are directly responsible for delivery of the hardware for the platform systems within Clyde Space, with the ground, (Primary) payload and launch providers selected by the UKSA with system design support. Assembly, integration, verification and test of the platform is the responsibility of Clyde Space, prior to delivery to the UKSA for launch.


Figure 2: Platform systems (image credit: Clyde Space)

Nominal mission: The majority of the mission shall be spent in nominal operations, starting 2-3 months after launch.


Figure 3: Typical mission orbit profile (image credit: Clyde Space)

Platform technology introduction and subsystems:

All platform subsystems have some new elements, the major developments for UKube-1 are:

STX (S-band Transmitter)

High data rate downlink up to 1 Mbit/s

AMAC (Active Magnetic Attitude Control)

The target is to achieve a pointing accuracy of ±5º

MIC (Mission Interface Computer)

Reconfigurable high performance computing

SFW (Onboard Software)

The software is service oriented and follows a modified PUS CCSDS standard software architecture

SADM (Solar Array Deployment Mechanism)

Higher power through solar array deployment

IE(Interface Emulator)

Platform-Payload interface emulator

Table 1: Summary of platform technology introduction into a nanosatellite

Platform structure: A Pumpkin off-the-shelf (skeletonized) STR (Primary Structure, 3U CubeSat) with integrated separation microswitch is used.

ADM (Antenna Deployment Mechanism): An omnidirectional UV monopole whip antenna for the FUNCube and UV TRX (UV Transceivers) will be deployed from the ISIS off-the-shelf ADM, controlled by the platform I2C data bus and routed through the FUNCube Transceiver.

SADM (Solar Array Deployment Mechanism): Deployment of the deployable solar arrays uses a Clyde Space developed SADM, consisting of release by resistive hot wire cutters and hinge mechanisms for array deployment to 135º from the face surface.



Figure 4: Overview of UKube-1 components and the modular architecture of the systems (image credit: Clyde Space)

AMAC (Active Magnetic Attitude Control): Basic guidance, navigation and control functionality uses a Clyde Space developed AMAC subsystem targeting a 2-axis pointing capability of ± 5º and sensing to 1º. Actuation is provided by a set of 6 magnetorquers (0.15 Am2 in XY and 0.12 Am2 in Z) embedded in the surface mount solar arrays, and sensing by a MEMs IMMU (Inertial & Magnetic Measurement Unit) consisting of gyros, accelerometers and magnetometers, and coarse sun sensors are mounted where volume allows on the solar arrays. A daughterboard containing a GPS interface is attached to the motherboard fed from the TOPCAT GPS receiver, with its antenna mounted in the +X surface mount solar array. Magnetic control is augmented with a 0.09 Am2 permanent magnet in the Z body axis.

EPS (Electric Power Subsystem): Power conditioning using a Clyde Space off-the-shelf next generation EPS, with 6 maximum power point tracking battery charge regulators providing protected 3.3 V @ 4 A, 5 V @ 4 A, 12 V @ 1 A, and battery V @ 4 A primary power lines. The subsystem also incorporates the Flight Activation System of Separation Microswiches, and the Flight Interface with External 5 V (TBC) USB Charge and Remove-Before-Flight pin.

• SAs (Solar Arrays): Use of off-the-shelf Clyde Space SAs with customized cut-outs. A total of 56 UTJ (Ultra Triple Junction, SpectroLab) standard solar cells are mounted on all faces to allow power generation at any attitude, although cell positioning is biased to the expected magnetic alignment, to produce a minimum typical power of 3.8 W worst case (estimated assuming pitch spin about XZ body axis. Two double sided cell deployable solar arrays (SA-D) are deployed in a centipede configuration along the longitudinal axis of the spacecraft, and a third as a spoiler. All surface mount solar arrays incorporate embedded magnetorquers, coarse sun sensors, the option for FSS (Fine Sun Sensors) in addition to cutaways through the panels for specific subsystems.

• Power storage uses an off-the-shelf Clyde Space 30 Whr standalone battery (BAT) based on soft-cased lithium polymer technology. The battery cells are arranged 2S3P, with a nominal voltage of 7.9 V.

• Power distribution uses a Clyde Space power switchboard (SWB) module with 18 switches to allow on/off switching of payload and auxiliary secondary power lines at the same voltages as the primary power lines (3.3, 5, 12, and BAT V). Each switch has overcurrent protection 10% above peak draw and inrush tolerance to 2 A over 10 ms.

OBC (OnBoard Computer): Platform and payload operations, C&DH (Command and Data Handling) uses a Gomspace Nanomind A712D with an ATMEL processor, 2 MB SDRAM, 4 MB FLASH and 2 GB SDCARD.
The onboard software (SFW) is embedded primarily in the OBC, the software uses an operation schedule for allocating resources to the payloads. The software is service oriented and follows a modified PUS CCSDS standard software architecture.


Figure 5: Block diagram of the C&DH subsystem (image credit: Clyde Space, Ref. 10)


Figure 6: Illustration of the deployed UKube-1 spacecraft in orbit (image credit: Clyde Space)

IMI (Inter-Module Interface): A common IMI between the subsystems uses the CSK PC/104 format headers, standoffs and boards for interfacing between internal modules within the STR (Primary Structure). Internal modules shall be stacked in the longitudinal axis, with 104 pins within the stackable headers providing all common data and power bus lines and signals. Six sets of up to four power buses shall distribute power through the interface in groups of 3.3 V, 5 V, 12 V and BAT V (where required):

• Primary power buses distributing to critical platform subsystems directly from the EPS (Electric Power Subsystem).

• Auxiliary power buses distributing to non-critical platform subsystems and routed through the power switchboard

• 4 sets of payload power buses distributing to primary payload subsystems and routed through the power switchboard

Four data buses shall be provided through the interface:

• 100 kit/s platform I2C data bus, interfacing the platform subsystems to the MIC (Mission Interface Computer) and FUNCube transceiver. In nominal operations, the MIC-FPGA is the master of all buses.

• 100 kbit/s payload I2C data bus, interfacing the primary payloads to the MIC

• Up to 1 Mbit/s communications SPI data bus, interfacing the S-band transmitter to payloads and AMAC (Active Magnetic Attitude Control) routed by or through the MIC.

• 9600 bit/s nominal communications UART data bus, interfacing the MIC to the UV transceiver.

RF communications:

• Primary transceiver capability for telecommand, telemetry, and redundant payload data, uses an Astro Dev off-the-shelf UVTRX (UV Transceiver), providing a UHF uplink and VHF downlink both using 9600 bit/s GMSK using CCSDS packets. When not transmitting, the transceiver shall operate in a Morse code beacon mode for broadcasting identification and basic health data for tracking. The UV TRX interfaces to two UV monopole whip antenna deployed from the ADM (Antenna Deployment Module).

• High data rate transfers of payload data shall use a CPUT (Cape Peninsula University of Technology) developed software defined STX (S-band Transmitter) for downlink at variable rates up to 1 Mbit/s O/QPSK (with 1/2, 1/4, 1/8 rates) for enhanced telemetry and payload data utilizing the IntelSat encoding standard, and CCSDS packets. The transmitter shall interface to a 7 dBi directional S-band patch antenna located on the –X (nadir pointing) surface mount SA (Solar Array). The STX has various modes of operation:

- In configuration mode the carrier frequency, power level, data rate and modulation scheme can be selected.

- In synchronization mode synchronization bytes are sent in order for the ground station receiver to achieve lock. The STX will accept data from the SPI bus and until the FIFO is full.

- In data mode data from the FIFO is transmitted to the ground station. Data is written to the FIFO at a suitable rate to prevent buffer underruns.

- The STX will automatically switch off after 15 minutes if not commanded to switch off via I2C.

• Secondary and safe mode transceiver capability for basic telecommand and telemetry uses the AMSAT-UK developed FUNTRX (FUNCube Transceiver) capable of VHF 1200 bit/s BPSK with FEC packet downlink and a UHF 100 ms proprietary DTMF-based uplink. The transceiver consists of three internal modules (CCT, RF, PA). The transceiver downlinks a standard telemetry packet with data from a Material Science Experiment which can be received at a USB dongle antenna for education & outreach into schools. A transponder mode of operation for radio amateurs is also available. The transceiver interfaces to two additional UV monopole whip antennas deployed from the ADM.


Launch: A launch of UKube-1 as a secondary payload is scheduled for the spring of 2013 on a Soyuz-2.1/Fregat vehicle from the Baikonur Cosmodrome, Kazakhstan. 12)

The primary payload on this flight the Meteor-M-N2 mission of Roshydromet/Planeta, Moscow, Russia.

The secondary payloads on this flight are:

• Baumanets-2, a technology microsatellite (~100 kg) of BMSTU (Bauman Moscow State Technical University)

• Monika-Relek (or MKA-PN2), a Russian microsatellite (solar and magnetosphere research)

• Venta-1 / V1-QSPnP1 (V1-QuadSat-PnP-1) the first nanosatellite (7.5 kg) project of Latvia built by LatSpace SIA of Ventspils.

• UKube-1, a nanosatellite of UKSA.

Orbit: Sun-synchronous orbit, altitude of ~ 820 km, inclination = 98.8º, LTDN (Local Time on Descending Node) at ?? hours.



Payload technology demonstrations: (TOPCAT, Janus, C3D, MPQ442, FUNcube)

The UKube-1 platform is able to accommodate at least three payloads compliant to the “payload interface requirements” and within the payload resource allocation for mass, volume, power and data:

- < 1080 g mass inclusive the CSK PC/104 connectors

- < 108 mm height envelope

- < 1200 mW sunlit average power (no eclipse operation)

- < 36 kB per orbit still provides valuable mission return.

UKSA started a payload competition among UK universities and industry. There were a total of 22 proposals for payload concepts on UKube-1. Of these, seven potential payloads have been progressed for UKube-1, which have now been down-selected to four at the Payload Selection Review, with the intention is to maximize the number of payloads flown on the first mission. In addition the MIC was incorporated as a payload with an off-the-shelf OBC selected as baseline at CDR(Critical Design Review). 13) 14)

• TOPCAT: Ionospheric study based on GPS measurements

• JANUS: Random number generation using radiation effects

• MPQ: Open source student satellite testbench

• C3D: Imager and CMOS radiation effects

• MIC: High performance computing technology demonstration.


TOPCAT (Topside Ionosphere Computer Assisted Tomography):

TOPCAT, a project of the University of Bath, will be the first GPS device aimed at measuring space weather conditions in the plasmasphere (the areas of space just beyond the Earth's atmosphere). The results from the measurements taken by TOPCAT will allow these conditions to be monitored and reacted to, reducing negative implications for GPS and improving systems such as satellite navigation and telecommunications. TOPCAT is funded by the University of Bath and the Bath Alumni Fund. 15) 16)

TOPCAT is a specialized dual-frequency GPS receiver that is suitable for operation in the space environment. The goal of TOPCAT is to study space weather through tomography, by observing the upper ionosphere and the plasmasphere. This could validate the technique for a future constellation mission to provide real space weather maps.


Janus (Random Number Generator using Single Event Upsets):

Janus is a device of EADS Astrium Ltd. with the objective to demonstrate on orbit the feasibility of a patent held by EADS Astrium (Patent: 20090316898, inventors: Omar Eman, Peter Bennie and James Stuart Glanfield) on using the radiation environment to demonstrate true random number generation for high data rate applications e.g. SAR. True random number generation is an essential component of secure communication systems required by many satellites.

A secondary objective of the device is to fly a technology demonstrator to determine the SEU (Single Event Upset) effects on a Xilinx FPGA (Field Programmable Gate Array) device (gathering statistics on the radiation performance). These devices are SRAM based, therefore potentially allowing in orbit reconfiguration. The ability to use these FPGA’s will enable further leaps in, in-orbit functionality and data rates. 17)


C3D (Compact CMOS Camera Demonstrator):

The C3D instrument is being developed as a collaboration between the CEI (Centre for Electronic Imaging) at the Open University and e2v technologies plc., a world-leading supplier of scientific imagers into the space market. The objectives are:

1) Provide a technology demonstrator to improve the TRL (Technology Readiness Level) of new CMOS (Complimentary Metal Oxide Semiconductor) sensors

2) Correlate the effects of space radiation with ground based testing - primarily SEE (Single Event Effects) and dark current increase

3) Capture images of the Earth (wide + narrow fields).

This imager is based on a new sensor technology which is being developed and evaluated for space use, based on 0.18 µm CMOS technology. The instrument, which is largely being developed by e2v-sponsored PhD students, will be designed to perform a variety of imaging tasks, including taking pictures of the Earth, and to be an experimental test-bed for radiation damage effects in space. 18)

The C3D instrument uses 3 CMOS detectors with a power consumption of < 1W and a mass of 200 g.


Figure 7: Preliminary view of the C3D imager (image credit: CEI, ev2)


Figure 8: Photo of the color CMOS detector (image credit: ev2)


Figure 9: Illustration of the experiment controller (image credit: CEi, ev2)


Figure 10: Photo of the C3D imager (image credit: Clyde Space)


MPQ442 (MyPocketQub 442):

This payload of UKSEDS (United Kingdom Students for the Exploration and Development of Space) is an open source myPocketQub IQEA (In-plane Qub with Experiment Array) with five experiments: 19) 20)

OpenSpace365 - Arduino with sensors allowing 365+ school pupils, university students and hobbyists to run their own experiment in space for a day
Note: “Arduino” is an open-source single-board microcontroller designed to make the process of using electronics in multidisciplinary projects more accessible.

OrbitView (popout camera) – browse interactive panoramas of UKube and the view from UKube. OrbitView is an imaging payload to capture 360º panoramas from multiple points on-orbit to allow anyone to ‘look out of the window’ of UKube-1.

Qubduino – low cost FPGA testing self repairing advanced virtual payloads. The objective is to space qualify GBP 10 FPGA, test self repairing algorithms and host advanced virtual payloads.

SuperLab – a physics experiment to characterize superconducting materials.

SuperSprite – satellite on a chip proof-of-concept with solar cells, energy storage, microcontroller and transceiver, and with a UHF downlink.

UKSEDS is a British student organization with members from more than a dozen universities. The MPQ442 experiment allows students and hobbyists to take part in a space mission.


MIC (Mission Interface Computer):

Platform and payload operations, command, and data handling uses a Steepest Ascent developed Mission Interface Computer (SA-MIC), primarily utilizing a flash-based Actel FPGA (MIC-FPGA) with softcore processor (ARM Cortex M1), and an MSP430 Safe Processor (MIC-SP) to monitor the primary and take control in off-nominal or power critical operations. The SA-MIC also contains a shared memory (8kB) for mission critical telemetries and flags, and 2 x 1 GB mass memories. 21) 22)


Figure 11: Block diagram of the MIC (image credit: Clyde Space)



The FUNcube payload is a transceiver, provided by AMSAT-UK in collaboration with ISIS (Innovative Solutions in Space BV). It provides UKube-1 with the capability for educational outreach to students at schools and colleges; it is also a “redundant” communications subsystem. The project features a 435 MHz (UHF) to 145 MHz (VHF) linear transponder for SSB/CW (Single Side Band/Continuous Wave) operation. 23)

Note: Since AMSAT-UK has already a FUNCube-1 CubeSat in development, the FUNCube payload on the UKube-1 mission is referred to as FUNCube-2.


Figure 12: Photo of the FUNCube-2 transceiver (image credit: Clyde Space, Ref. 7)

1) “UK Space Agency to launch Britain's first CubeSat,” UKSA, July 21, 2010, URL:

2) “UK Space Agency kicks off CubeSat pilot program,” UKSA, Nov. 10, 2010, URL:

3) “Fuelling The Clyde Space Rocket,” Space Daily, Feb. 1, 2011, URL:

4) Ritchie Logan, Steve Greenland, “UKube-1: A Multi-Payload Technology Demonstration Platform,” 8th Annual CubeSat Developers’ Workshop, CalPoly, San Luis Obispo, CA, USA, April 20-22, 2011, URL:

5) Chris Castelli, “Cubesats for Innovation, Science and Education, Technology, Science and Exploration,” 7th Appleton Space Conference, RAL (Rutherford Appleton Laboratory), Didcot, UK, Dec. 8, 2011, URL:

6) “UKube-1;” UKSA, URL:

7) Steve Greenland, “UKube Program, its Payloads & Enabling Technologies,” 2012 Summer CubeSat Developers’ Workshop, Logan, Utah, USA, Aug. 11-12, 2012, URL:

8) “UKube-1 final design approved,” AMSAT-UK, URL:

9) Craig Clark, Kevin Worrall, “Plug and Play Attitude Control,” Summer CubeSat Developer's Workshop, USU, Logan, UT, August 6-7, 2011, URL:

10) Craig Clark, “UKube-1 Platform Design,” Summer CubeSat Developer's Workshop, USU, Logan, UT, USA, August 6-7, 2011, URL:

11) Craig Clark, Karin Viergever, Andy Vick, Ian Bryson, “Achieving Global Awareness via Advanced Remote Sensing Techniques on 3U CubeSats,” Proceedings of the 26th Annual AIAA/USU Conference on Small Satellites, Logan, Utah, USA, August 13-16, 2012, paper: SSC12-IV-2

12) “UK's Cubesat books a ride on Russian rocket,” Space Daily, Sept. 26, 2012, URL:

13) Information provided by Steve Greenland of Clyde Space Ltd., Glasgow, UK.


15) “TOPCAT – Topside Ionosphere Computer Assisted Tomography,” URL:






21) P. Karagiannakis, S. Weiss, J. Bowman, “Solving the Digital Signal Processing Problem for CubeSats,” 4th European CubeSat Symposium, ERM (Ecole Royale Militaire), Brussels, Belgium, Jan. 30-Feb. 1, 2012

22) “First Scottish-built satellite UKube-1 to launch in 2013,” March 20, 2012, URL:


The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates.