AlSat Nano / AlSat-1N
AlSat Nano (Algerian Nanosatellite)/AlSat-1N
In March 2014 the UK Space Agency (UKSA) and Algerian Space Agency (ASAL) signed a MOU (Memorandum of Understanding) under which the two parties agreed to enhance collaboration in space programs. A specific action identified following the MOU was the establishment of a joint educational CubeSat development program to be delivered by SSC (Surrey Space Centre), utilizing its ties and heritage in the field. 1) 2)
A 3U CubeSat standard nanosatellite, AlSat Nano, was designed, built and launched as part of the joint education program at SSC (Surrey Space Centre) to Algerian students. The UK (SSTL) is responsible for the platform hardware design, development and build, ASAL will undertake the final AIT, launch and operations.
The UK program is being delivered by the SSC (Surrey Space Centre) of the University of Surrey, funded and steered by the UKSA (UK Space Agency). The program involves a number of Algerian graduate students hosted at SSC and focused on the development and operation of a nanosatellite as a hands-on learning exercise for the students and ASAL staff, to demonstrate the practical implementation of this type of low cost space technology. Graduate students are enrolled on courses related to key areas of satellite technology. Additional focused training programs were delivered to ASAL staff in the areas definition, implementation and testing of a full nanosatellite.
To increase the value of the mission and widen the reach of the program, it was decided that the AlSat-1N nanosatellite would carry self-funded payloads supplied by the UK CubeSat community, and selected through a competitive process, effectively performing a technology demonstration mission. The three payloads demonstrate novel technologies in mechanisms, imagery and power generation. These payloads occupy approximately half of the spacecraft volume. The AlSat-1N spacecraft was designed, integrated and tested by the SSC with hands-on contribution by ASAL students. The AlSat-1N spacecraft went from design to delivery in 18 months. 3)
The main goals of this program are:
• To provide education and support allowing development of space technologies and applications which are of practical use to Algeria, at a competitive cost which will help to create sustainable growth in the country.
• To offer a flight opportunity for payloads and/or bus elements to the UK nanosatellite & CubeSat community, selected for flight through an open competition which issued by UKSA in collaboration with the SSC and ASAL.
The overarching aim of the program is to foster an enhancement of collaboration in space programs between the UK and Algeria, in line with intentions expressed in a MOU. — The growth of an appropriately educated workforce who can exploit space technologies and their applications has been identified as a key enabler to the diffusion of space technologies. Supporting education in this area contributes to the development of this sector of the economy of Algeria and enhance that of the UK by access to new markets. This project provides an opportunity to develop existing skillsets through hands on engineering across a full nanosatellite mission lifecycle. To this end, the program includes an educational component consisting of five student positions (2 MScs and 3 PhDs) hosted at the Surrey Space Centre, and whose project based activity involved aspects of the design and manufacture of the Nanosatellite. Through PhD programs, students acquire a more focussed knowledge, and an ability to advance the current knowledgebase (e.g. technologies or methodologies to analyze research problems), learning how to develop new techniques and/or new applications. These can lead more efficient or new industrial processes, driving progress and economic growth. The inclusion of PhD level education generates the capability for sustained space activities.
The various activities under the AlSat-Nano program are brought together by the development of the nanosatellite and its operation, which are an integral part of the joint program.
The AlSat-Nano Program offered a flight opportunity to the UK CubeSat community for competitively selected self-funded payloads, and potentially novel platform components. Three payloads were selected by panel in February 2015.
The AstroTube Boom payload is divided into 3 elements: the main PCB (Printed Circuit Board), the boom mechanism and the secondary (sub payload) PCB. The OSS (Oxford Space Systems) developed AstroTube payload comprises the following subsystems:
• 1.5m long extendible rolled composite boom, boom mechanism, and associated main PCB.
• Magnetometer and associated electronic circuit (SpaceMag-Lite)
• 2 x RADFET (Radiation-Sensing Field-Effect Transistor) and associated electronic circuit.
The extendible element of the boom sub-system is a 20 mm diameter open-section flexible composite member with a 224° subtended angle and 0.3 mm thickness. Epoxy-based plain weave carbon fiber pre-impregnated has been used in the manufacturing of the boom as this material type has low outgassing characteristics and relatively high radiation tolerance. The boom element itself can be fully or partially deployed; it can be retracted and stowed from either of these two states.
The SpaceMag-Lite is a three axis, lightweight, fluxgate magnetic sensor, offering measurement performance from DC to 1 kHz, for field strengths up to ±60 µT. The RADFETs (Radiation-sensitive Field Effect Transistors) are micro-miniature silicon p-type MOSFETs (Metal-Oxide Semiconductor Field Effect Transistors) which act as an integrating dosimeter, measuring dose in rad or Gy (SI).
Figure 1: Photo of the AlSat-1N AstroTubeTM Boom (image credit: AlSat-1N Team)
C3D2 (Compact CMOS Camera Demonstrator 2)
C3D2 is based on the C3D imager that has been previously flown on UKube-1. 4) The Open University developed this payload in collaboration with XCAM Ltd. of Northampton, UK and e2v Technologies of Chelmsford. C3D2 hosts three e2v ‘Sapphire' CMOS imaging sensors, each capable of implementing multiple imaging modes, in a three imager arrangement; two wide field imagers (WFI) and one experimental narrow field imager (NFI). One of the WFI cameras has a focal length of 45 cm and is aligned to image the Boom payload once deployed. The focus of the other WFI is set to infinity, it utilizes a Bayer filter to provide full RGB color. Full size images are 1200 x 1080 pixels.
Imagery data is transferred from the payload to the OBC via a file transfer protocol and optionally allows for compression, windowing and auto/manual exposure settings. For each image capture, the payload also provides a scaled 120 x 100 thumbnail image for initial analysis.
Figure 2: Photo of the AlSat-1N C3D2 payload (image credit: AlSat-1N Team)
C3D2 can also perform thermometry and radiation dose measurements using a suite of distributed sensors on an ESS (Experiment Support System). This data is accessed via a small "housekeeping" packet.
TFSC (Thin Film Solar Cell)
The CSER (Centre for Solar Energy Research) of Swansea University (in south-west Wales, UK) is demonstrating a novel thin film solar cell structure. The structure is the first to utilize from Qioptiq Space Technology Ltd's (QST) ultra-thin and flexible cover glass as both the substrate and radiation protection for the solar cell.
The technology is based on thin film cadmium telluride (CdTe), deposited directly onto ultra-thin space qualified cover glass. This offers a potentially high specific power, low-cost technology with the added benefit of allowing a high degree of solar array flexibility for improved stowage volume and novel deployment strategies.
The TFSC payload is designed to measure the (non-linear) current-voltage (I-V) response of 4 experimental thin-film solar cells in orbit when illuminated by the Sun.
The TFSC payload consists of two elements: An externally mounted board, which is mounted on a solar-irradiated surface and an internally mounted controller board. The solar cell test has 4 test cells with a mounted LM35 temperature sensor.
Figure 3: Photo of the AlSat-1N TFSC payload (image credit: AlSat-1N Team)
CubeSat Design & Development
Requirements for payload providers were defined as part of the announcement of opportunity for payloads. Similarly, platform requirements were defined at this time based on the objectives of the AlSat-Nano program. 5)
The mechanical design of the AlSat-1N spacecraft was designed in-house at the SSC based on experience of existing commercially available structure systems for ease of integration and precision of alignment. The AlSat-1N structure uses distinct Aluminum bracketed modules for ease of assembly/disassembly. The spacecraft has a platform module for all avionics, and distinct structural modules for the payloads. These modules are integrated and aligned using externally mounted rails and side panels incorporating solar cells.
Qualification of the novel structure was performed via vibration testing on a SQM (Structural Qualification Model). The platform avionics is composed of:
• Stellenbosch ADCS (Attitude Determination and Control Subsystem) that additionally acts as an OBC. The ADCS includes sun sensors, magnetometer, gyro, sun and nadir cameras for sensing and magnetorquers and momentum wheel for actuation.
• The power system, with the ClydeSpace 3rd generation 3U EPS (Electrical Power Subsystem), and custom solar panels (with Azur Space cells with 28% efficiency) and a standalone battery of 30 Whr.
• The communications with the ground station are executed through the Surrey Transceiver (STRx), using the UHF band to transmit and the VHF to receive.
• An interface board and a bespoke power switch board, both made in the SSC, provide appropriate interfaces with the EGSE (Electrical Ground Support Equipment) and with the payloads, respectively.
The spacecraft uses a Copper-Beryllium tape form antenna system, with the UHF Tx and VHF Rx antennas deploying from opposite facets of the spacecraft. The antennas are wrapped around the long-axis of the spacecraft and retained by burn-wires for launch.
Figure 4: AlSat-1N CAD rendering (image credit: AlSat-1N Team)
Figure 5: Block diagram of AlSat-1N (image credit: AlSat-1N Team)
Software Design & Development: Software was developed for AlSat-1N based on a RTOS (Real Time Operating System) incorporating a HAL (Hardware Abstraction Layer) and higher level mission modules for example: payload, file transfer, beaconing, etc. The RTOS development makes use of auto-generated software modules from TT&C spreadsheets allowing for rapid software build and simple configuration management. 6)
Several dedicated modules were developed by Algerian PhD students where these aligned with their area of research. The AlSat-1N software includes a bootloader, allowing for upload of full software binaries whilst on orbit. A thoroughly tested "gold copy" is held and protected on the spacecraft and the spacecraft will always revert to this safe version in event of a reset.
CubeSat Integration & Test: AlSat-1N was delivered on a rapid schedule with parallel development of the electronics and spacecraft software. As such, three key phases of testing were conducted: i) subsystem/system testing – verifying and characterizing the electrical, mechanical and interface behavior of the system ii) EVT (Environmental Verification Testing) – verifying consistent electrical, mechanical and interface behavior pre and post EVT, iii) final mission SEET (System End to End Testing) – verify the system functionality with final flight version of software run in flight like configuration. - This approach allowed the development of software beyond basic functionality to be partially decoupled from the spacecraft qualification program.
Figure 6: Photo of the AlSat-1N FM during integration (left) and completed with umbilical (right), image credit: AlSat-1N Team
Subsystem/System testing: A phased integration approach was taken with subsystem level testing performed on incoming hardware prior to integration into the spacecraft system. Repeated testing was performed as each subsystem was added and to the system to confirm consistent operation of subsystems. While the integration activity was led by SSC staff, the Algerian PhD students provided significant contributions to this phase, building experience in hands on testing and debugging. The involvement of the Algerian students in this phase is a key feature of the SSC Program, with the first-hand experience gained being crucial to on-going, repeated success.
EVT (Environmental Verification Testing): AlSat-1N followed an EM & PFM (Engineering Model and Proto-Flight Model) philosophy. As such, the spacecraft was qualified for flight primarily by testing on the Proto-Flight Model via vibration, thermal and TVAC (Thermal Vacuum) testing.
Vibration testing was carried out on the integrated spacecraft in flight configuration using the flight deployment pod. This test followed the PFM approach with qualification level loads for acceptance level durations. Test levels were as per the launch vehicle (PSLV) requirements in all three axes including random vibration, combined sine and quasi-static test, with sine surveys performed between tests. The vibration test was passed with consistent functional testing of the spacecraft before and after the vibration test.
Following vibration testing, the spacecraft was subject to TVAC testing over multiple thermal cycles, in addition to a 24 hour bake-out, between -20ºC and +50ºC and dwells at the temperature extremes. The spacecraft was subject to functional testing at each hot and cold dwell to verify operation of all subsystems and payloads and to characterize temperature sensors and behavior of the RF and power systems. The burn wire antenna deployment mechanism was performed during a cold dwell test.
Additional thermal testing was performed following the TVAC test after identifying some non-ideal behaviors during the TVAC testing. In addition to the PFM qualification path, shock testing was also performed on an SQM to verify no debris creation, while avoiding over-testing of the PFM.
SEET (Mission System End-to-End Testing): Prior to delivery, the team completed a simulated LEOP (Launch and Early Operations Phase) run through checkout of the spacecraft. This testing was conducted over 100 hours of continuous operation with no resets of the OBC and simulated the early phases of the mission from deployment out of the pod including antenna release and beaconing, through platform commissioning and ending in payload commissioning with minimum mission success criteria achieved. This testing was performed whilst undergoing thermal cycle testing and using worst case average orbit power. These tests brought the total uptime on the integrated spacecraft in flight configuration to 560 hours, almost all of which was conducted over RF communications using the SSC groundstation. The spacecraft then had final external flight prepped performed followed up an outgoing health check prior to ship out to launch site.
Figure 7: AlSat-1N FM undergoing Boom deployment (image credit: AlSat-1N Team)
As part of the education and Knowledge Transfer aspects of the AlSat-Nano Program, training sessions were held covering three key areas for ASAL Staff: AIT, EVT and Operations, the last being crucial for successful handover of the spacecraft from the SSC to ASAL. A summary of the training sessions is given in Figure 8.
AIT Training: A one week session was held with ASAL staff members to provide an introduction to the principles and processes of AIT, and particularly in relation to CubeSats. This session included taught sessions covering the design of the spacecraft, software, cleanroom training, and mechanical design. A supervised sequence of performing checkout, characterization and acceptance of an EM Power switch board, culminating in demonstration of the FM model in the CubeSat system.
EVT Training: Experienced ASAL engineers participated in review and execution of EVT activities, specifically PFM level vibration testing and preparation for TVAC. Given the already high level of experience of the engineers, training aspects focussed on the specifics of nanosatellite test campaigns and how these differ from testing on larger platforms.
Operations Training: Operation training was split into two sessions:
1) One week of familiarization with the spacecraft and groundstation tied with the AIT training program. This provided an introduction to the spacecraft and groundstation facilities, providing time to digest and perform background reading to prepare for the main session.
2) Two weeks dedicated training in July 2016:
- The first week was aimed at providing formal training for ASAL students and staff on the AlSat-1N nanosatellite. This consisted of a series of sessions with key SSC staff and academics providing hands on training and exercises covering TM/TC, satellite management, payload operations, file transfers and scripting.
- The second week was an accelerated walkthrough of LEOP, aimed at providing a sample of the tasks to be performed from the days prior to launch through to payload commissioning.
Figure 8: Summary of training under the AlSat-Nano program (image credit: AlSat-1N Team)
The SSC engineering team were markedly removed from the second training week and the ASAL team were expected to operate from the User Manual and CONOPS (Concept of Operations) Plan for the first week of operations where the SSC artificially accelerated the timelines for the purpose of training. SSC staff activated the FM spacecraft on the bench and supervised as the operations students controlled the spacecraft over RF replicating groundstation "passes". The SSC team simulated contact duration, RF packet drop, groundstation hardware faults and spacecraft anomalies to demonstrate and test the trainees. The trainees were required to develop their pass plans based on the LEOP plan and operations handbook, with review and discussion with SSC staff before and after each simulated pass, but did not interfere during the passes themselves.
As part of the AlSat-Nano program, a groundstation was established at ASAL's CDS (Centre de Developpment des Satellites) facility in Algeria.
SSC MOC (Mission Operations Center): The SSC ground-station is a VHF/UHF twin-antenna system that allows flexible, reconfigurable operation, including breakout of the signal path to both hardware modems and SSC-developed software-defined radio modules for both uplink and downlink. The SSC baseline system, developed for the STRaND-1 mission , uses a hardware TNC (Terminal Node Controller) for modulation and demodulation. A HPA (High Power Amplifier) capable of increasing the RF broadcast power is optionally included in the uplink path, with automatic control of this amplifier under computer control.
CDS Groundstation: The ASAL groundstation is based on the SSC facility and the equipment list for the installation was specified by the SSC after an initial site visit. ASAL engineers designed, built and integrated the system at the CDS site with advice from the SSC. A follow up site visit by SSC engineers assisted in the commissioning of the facility, and confirmed its operational readiness.
Figure 9 depicts the ASAL ground station system diagram established to support the AlSat-Nano mission at CDS in Oran. A primary PC maintained within the Ground Segment control center interfaces with both the RF chain and rotator systems. The RF chain is based around an ICOM-9100 transceiver controlled via the ground segment control PC via a Kantronics TNC (KWM-9612+). Doppler frequency control of the ICOM is via the control PC. The ICOM Tx line is routed to the 144 MHz antenna – an optional HPA can be included in the system on the transmit chain if found to be needed.
The ICOM Rx is connected to the 434MHz antenna through a masthead mounted UHF LNA (SP-70). The antennas are mounted on a roof-top 10 m mast at the ground segment site. Tracking rotation in Azimuth/Elevation is via Yaesu G-5500 rotators controlled with Yaesu GS-232 interfaced to the groundstation PC.
Figure 9: AlSat-1N ASAL groundstation (image credit: AlSat-1N Team)
MCS (Mission Control Software): The MCS consists of a database and associated programs to allow spacecraft controllers to efficiently control both the groundstation and spacecraft. While used to support multiple on-going missions at the SSC, it was developed in parallel to the AlSat-1N CubeSat and the design was driven heavily by the operational requirements of this mission.
The MCS developed by the SSC is a core part of the training partnership developed with ASAL. Operations training was based around the software package and its interaction with the spacecraft. In earlier phases, aspects of usability and interfacing were iterated based on feedback from ASAL operators. As the project progressed and operator expertise with the software increased, deeper modifications and updates were made by the SSC/ASAL team.
Spacecraft Emulator: A spacecraft emulator was developed as a means to test the groundstation prior to launch. The emulator consists of a Flight representative STRx Transceiver connected to an OBC emulator development board running the spacecraft software. Antennas are included in the emulator which is integrated into a hard-case. The emulator allows verification of the full chain bidirectional interface over RF from the MCS to OBC and back again.
Launch: The AlSat-1N 3U CubeSat was launched on September 26, 2016 as a secondary payload on the PSLV-C35 flight of ISRO from SDSC (Satish Dhawan Space Center) SHAR on the east coast of India. The primary payload on this flight was SCATSat-1 (Scatterometer Satellite-1), a minisatellite (371 kg) of ISRO. 7) 8)
Orbit: Sun-synchronous orbit of SCATSat-1, altitude = 720 km, inclination = 98.1º, LTAN = 9:30 hours. The satellite is allowed to drift to an LTAN of 8:45, orbital period of 99.19 minutes.
All secondary payloads were deployed into an orbit of ~670 km altitude. — This was ISRO's first multi-orbit mission. It was the longest ever PSLV flight which lasted for more than 2 hours 15 minutes. According to ISRO, PSLV-C35 successfully placed all satellites into their respective orbits.
• Pratham, a nanosatellite (10 kg) of ITT, Bombay
• PISAT, a nanosatellite (5.3 kg) of PES University, Bengaluru, India
• BlackSky Pathfinder, a microsatellite (44 kg) of BlackSky Global.
• AlSat-1N (Nano), a 3U CubeSat of ASAL (Algerian Space Agency)
• CanX-7, a 3U CubeSat (8 kg) of UTIAS/SFL, Toronto, Canada.
• September 2017: Continued operations of the platform and payloads have been conducted throughout the mission lifetime. Additional scripting has been uploaded to the spacecraft to perform varied operations of the payloads and platform providing capability for regular data collection from all payloads (Ref. 3).
- Operations continue to be a shared activity between the SSC and the ASAL team. The SSC and ASAL are in scheduled daily contact via email and regular telecons. ASAL operators provide handover reports updating all parties on the status of the spacecraft at the end of the day's passes and the activity conducted in that day. All downloaded data is logged on a shared online drive for ease of access. Weekly to fortnightly teleconferences are held to review recent activity, discuss spacecraft behavior and plan ongoing and upcoming operations. Other project partners (ie: UKSA and Payload providers) receive reports via the Basecamp online tool on a fortnightly to monthly basis, in addition to email updates. Operations requests from payload providers are sent to both the SSC and ASAL. SSC continues to provide advice on spacecraft operation, but all decisions and planning are ultimately made by the ASAL team.
- In the course of operations, both the SSC and ASAL have made upgrades to the MCS software controlling the groundstations. This provides a bi-directional flow of capability providing, for example: improved user interfaces, report generation, alert messaging and data management.
- These activities along with the day-to-day operations and in-orbit issues resolutions were an opportunity to reinforce and increase significantly the Knowhow transfer for ASAL trained operators especially on the spacecraft architecture and software. In this way, a greater level of autonomy and in-depth understanding of platform and payload behavior were achieved.
• July 24, 2017: AlSat Nano has been successfully operating in orbit for over 9 months. A status update is provided as the mission approaches its one year milestone. 9)
- Stable, healthy spacecraft platform
- All subsystems functional – over 15,000 ground to space commands successfully sent
- Strong communications link – over 1000 files downloaded so far
- Low spin rate
- Longest uptime: 27.4 days
- On board ADCS (Attitude Determination and Control Subsystem) verified and activated
- Regular datasets returned for TFSC (Thin Film Solar Cell) payload
- Multiple image capture and download for all three C3D2 payload cameras – 105 image files downloaded in total so far, including 16 full size images.
- AstroTube Boom payload deployed and stowed multiple times, including full 1.5 m length, captured with dedicated C3D2 camera.
• Mission Successes: The TFSC (Thin Film Solar Cell) payload is the first solar cell deposited directly onto cover glass to be deployed in space and successfully return data. The data returned show an improved performance surpassing that of the terrestrial measurements with Voc increasing by almost 25%. The improvement in Voc is attributed in part to lower cell temperature measurement and extended light soaking (Ref. 3).
- The TFSC test payload, led by Swansea University, is the first solar cell deposited directly onto cover glass to be deployed in space and successfully return data. The ultra-thin (just 0.1 mm thick) cover glass, developed by industrial partners Qioptiq Ltd, allows for extremely high power to weight ratio which is crucial for saving costs in spaceflight. Flight data returned so far show extremely promising performance, and with proven materials heritage there are now clear routes to secure further funding and eventually commercialize the payload.
- The AstroTubeTM Boom payload from OSS has been deployed to full length and retracted demonstrating the performance of the technology. The Boom payload has been demonstrated to report the deployment position in this process. Figure 10 shows an image of the Boom deployed to its full length.
Figure 10: AstroTubeTM Boom payload deployed to 1.5 m and imaged by C3D2 (image credit: AlSat-1N Team)
- Regular image capture has been performed for the C3D2 payload with >100 captures and thumbnail downlink. Multiple good quality full size images have been downloaded from the Boom and Earth imagers in both compressed and uncompressed formats. Imagery has captured a range of terrain across latitudes. A sample color image from the C3D2 WFI is shown in Figure 13.
Figure 11: C3D2 image of the Thai/Cambodia border. A partial length deployment of the AstroTubeTM Boom tip is visible at the bottom of the image (image credit: AlSat-1N Team)
• January 9, 2017: AlSat Nano, a UK-Algeria CubeSat mission, has captured its first full color image following its launch in September 2016. 10)
Figure 12: Image taken from space of the Arkhangelsk Oblast region, on the North West coast of Russia (image credit: Alsat Nano mission, Open University,, December 2016)
Legend to Figure 12: The image was taken by the Open University C3D2 instrument's wide field camera on 3 December 2016, over the Arkhangelsk Oblast region, on the North West coast of Russia. It was captured under twilight conditions at dawn, showing the coastline to the right, and a brief winter sunrise over the arctic region with a deep red-brown hue. Through the cloud cover there is evidence of hills and snow on mountains, and mist in the river valleys. The object in the foreground is the OSS (Oxford Space Systems) AstroTubeTM Boom payload, also carried on board the spacecraft. - This marks an important milestone for the mission as all core payloads have now been commissioned successfully, paving the way for further scientific and commercial exploitation.
Figure 13: The Alsat Nano image of Figure 12 is overlayed on Google Maps (image credit: Alsat Nano mission, Open University, December 2016. Map credit: Google Maps)
Dr Abdewahab Chikouche, Director of Space Programs at ASAL (Algerian Space Agency), said: The Alsat-1N project is a concrete example of the success of our cooperation with UKSA. This project, very enriching from the scientific and technological point of view, allowed ASAL engineers to progress in the integration and testing of nanosatellites and acquire autonomy in its operation. This project will enable Algerian researchers and academics to strengthen national capabilities in advanced space technology."
• November 2016: Payload commissioning had been intended to be performed fully using individual commands during groundstation passes, however, it quickly became clear that flight timing constraints would prevent operators from executing all necessary commands within a single pass. As a consequence, having to deactivate payloads during eclipse to protect long-term battery health as per the CONOPS led to bringing forward the commissioning of the on-board automation and scripting capability. Thus, this module was activated after TFSC commissioning. The automation was used in the commissioning of C3D2 and Boom payloads. C3D2 was used to capture and downlink a full size image of the Boom (Figure 14) by November 2016 ending the initial commissioning phase (Ref. 3).
Figure 14: First AlSat-Nano full size image showing the partially deployed Boom (image credit: AlSat-1N Team)
• October 3, 2016: Early commissioning progress was rapid with WOD (Whole Orbit Data) collections within the first week to monitor battery voltage and temperature throughout the orbit. This also verified the file transfer protocol using packets of 220 bytes. — Once the platform stability had been verified, the payloads were in turn commissioned by performing basic operations:
- TFSC – collection of data sample in solar illumination.
- C3D2 – capture and transfer of thumbnail images from each imager.
- Boom – Deployment of Boom to >30 cm length.
• A phased approach was taken in commissioning the spacecraft with a transition to handover from the SSC groundstation to ASAL groundstation as prime. In sequence, groundstation reception, transmission and file handling were performed at the SSC and then the respective function verified at the ASAL facility. At all times, ASAL operators were in control of the CubeSat at both sites, with SSC staff providing advice and facility support (Ref. 3).
Figure 15: AlSat-1N SSC to ASAL prime groundstation verification and handover process (image credit: AlSat-1N Team)
• September 26, 2016: Reception and decoding of beacon telemetry was made at the SSC groundstation, followed by the ASAL groundstation in Oran, Algeria on the first pass. The initial beacon telemetry showed spacecraft uptime as expected, confirmation of antenna deployment with strong RF signal (35dB SNR), good battery health and temperature. The data were decoded into the MCS at both groundstations (Ref. 3).
- A wealth of data was provided by the Amateur Satellite community around the world, particularly on the first few days which allowed the team to quickly review the health of the spacecraft looking particularly at battery voltage, battery temperature and software stability – all were found to be in expected ranges (Ref. 8).
1) "Request for Information AlSat-Nano Program," UKSA, Oct. 10, 2014, URL: https://www.gov.uk/government/uploads/system/uploads/attachment
2) "UK Space Agency's second CubeSat mission is taking shape," UKSA, March 5, 2015, URL: https://www.gov.uk/government/news/u
3) Ben Taylor, Richard Duke, Brian Stewart, Chiara Massimiani, Fawzi Djamane, Christopher P. Bridges, Guglielmo Aglietti, Abdelmadjid Lassakeur, Mohammed Amine Ouis, Mohammed Cherif Ladouze, Khaled Meftah, Craig Underwood, Abdelwahab Chikouche, Djamel Eddine Baba Hamed, "AlSat-Nano: Knowledge Transfer to Operational Partnership," Proceedings of the 68th IAC (International Astronautical Congress), Adelaide, Australia, 25-29 Sept. 2017, paper: IAC-17-B4-1.8
4) R. D. Harriss, A. D. Holland, S. J. Barber, S. Karout, R. Burgon, B. J. Dryer, N. J. Murray, D. J. Hall, P. H. Smith, T. Grieg, J. H. Tutt, J. Endicott, P. Jerram, D. Morris, M. Robbins, V. Prevost, K. Holland, "Compact CMOS Camera Demonstrator (C3D) for Ukube-1," Proceedings of SPIE, Vol. 8146, 'UV/Optical/IR Space Telescopes and Instruments: Innovative Technologies and Concepts V,' 8 September 2011, San Diego, USA, https://doi.org/10.1117/12.895986, URL: http://oro.open.ac.uk/34697/1/Harriss%20-
5) "Request for information: AlSat Nano payload," UKSA, 10 October 2014, URL: https://www.gov.uk/government/publications/request
6) R. Duke, C. P. Bridges, B. Stewart, B. Taylor, C. Massimiani, J. Forshaw, G. Aglietti, "Integrated Flight & Ground Software Framework For Fast Mission Timelines, " Proceedings of the 67th IAC (International Astronautical Congress), Guadalajara, Mexico, Sept. 26-30, 2016
7) "PSLV-C35 / SCATSAT-1, ISRO, Sept. 26, 2016, URL: http://www.isro.gov.in/launcher/pslv-c35-scatsat-1
8) "AlSat-1N , Launch & Early Operations," SSC, URL: https://www.surrey.ac.uk/surrey-space-centre/missions/alsat-1n
9) "Status update for record breaking UK-Algeria CubeSat mission AlSat Nano," UKSA, July 24, 2017, URL: https://www.gov.uk/government/news/status-update-for-record-breaking
10) "First color image for joint UK and Algerian CubeSat," UKSA, 9 Jan. 9 2017, URL: https://www.gov.uk/government/news/first-colour
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 (firstname.lastname@example.org).