Optical communication on CubeSats - Enabling the next era in space science

CubeSats are excellent platforms to rapidly perform simple space experiments. Several hundreds of CubeSats have already been successfully launched in the past few years and the number of announced launches grows every year. These platforms provide an easy access to space for universities and organizations which otherwise could not afford it. However, these spacecraft still rely on RF communications, where the spectrum is already crowded and cannot support the growing demand for data transmission to the ground. Lasercom holds the promise to be the solution to this problem, with a potential improvement of several orders of magnitude in the transmission capacity, while keeping a low size, weight and power. Between 2016 and 2017, The Keck Institute for Space Studies (KISS), a joint institute of the California Institute of Technology and the Jet Propulsion Laboratory, brought together a group of space scientists and lasercom engineers to address the current challenges that this technology faces, in order to enable it to compete with RF and eventually replace it when high-data rate is needed. After two one-week workshops, the working group started developing a report addressing three study cases: low Earth orbit, crosslinks and deep space. This paper presents the main points and conclusions of these KISS workshops.Comment: 7 pages, 5 figures, 2 tables, Official Final Report of KISS (Keck Institute for Space Studies) workshop on "Optical communication on CubeSats" (http://kiss.caltech.edu/workshops/optcomm/optcomm.html

Quantum Communication Uplink to a 3U CubeSat: Feasibility & Design

Satellites are the efficient way to achieve global scale quantum communication (Q.Com) because unavoidable losses restrict fiber based Q.Com to a few hundred kilometers. We demonstrate the feasibility of establishing a Q.Com uplink with a tiny 3U CubeSat (measuring just 10X10X32 cm^3 ) using commercial off-the-shelf components, the majority of which have space heritage. We demonstrate how to leverage the latest advancements in nano-satellite body-pointing to show that our 4kg CubeSat can provide performance comparable to much larger 600kg satellite missions. A comprehensive link budget and simulation was performed to calculate the secure key rates. We discuss design choices and trade-offs to maximize the key rate while minimizing the cost and development needed. Our detailed design and feasibility study can be readily used as a template for global scale Q.Com.Comment: 24 pages, 9 figures, 2 tables. Fixed tables and figure

It's hip to be square : The CubeSat revolution

With the launch of the UK’s first commercial CubeSat, UKube-1, on the horizon, Malcolm Macdonald and Christopher Lowe look at what the future holds for this standardised spacecraft platform

On orbit validation of solar sailing control laws with thin-film spacecraft

Many innovative approaches to solar sail mission and trajectory design have been proposed over the years, but very few ever have the opportunity to be validated on orbit with real spacecraft. Thin- Film Spacecraft/Lander/Rovers (TF-SL Rs) are a new class of very low cost, low mass space vehicle which are ideal for inexpensively and quickly testing in flight new approaches to solar sailing. This paper describes using TF- SLR based micro solar sails to implement a generic solar sail test bed on orbit. TF -SLRs are high area- to-mass ratio (A/m) spacecraft developed for very low cost consumer and scientific deep space missions. Typically based on a 5 μm or thinner metalised substrate, they include an integrated avionics and payload system -on-chip (SoC) die bonded to the substrate with passive components and solar cells printed or deposited by Metal Organic Chemical Vapour Deposition (MOCVD). The avionics include UHF/S- band transceivers, processors, storage, sensors and attitude control provided by integrated magnetorquers and reflectivity control devices. Resulting spacecraft have a typical thickness of less than 50 μm, are 80 mm in diameter, and have a mass of less than 100 mg resulting in sail loads of less than 20 g/m 2 . TF -SLRs are currently designed for direct dispensing in swarms from free flying 0.5U Interplanetary CubeSats or dispensers attached to launch vehicles. Larger 160 mm, 320 mm and 640 mm diameter TF -SLRs utilizing a CubeSat compatible TWIST deployment mechanism that maintains the high A/m ratio are also under development. We are developing a mission to demonstrate the utility of these devices as a test bed for experimenting with a variety of mission designs and control laws. Batches of up to one hundred TF- SLRs will be released on earth escape trajectories, with each batch executing a heterogeneous or homogenous mixture of control laws and experiments. Up to four releases at different points in orbit are currently envisaged with experiments currently being studied in MATLAB and GMA T including managing the rate of separation of individual spacecraft, station keeping and single deployment/substantially divergent trajectory development. It is also hoped to be able to demonstrate uploading new experiment designs while in orbit and to make this capability available to researchers around the world. A suitable earth escape mission is currently being sought and it is hoped the test bed could be on orbit in 2017/18

JUMPSAT: Qualifying three equipments in one Cubesat mission

We work on a student 3U Cubesat mission, called JUMPSAT, expected for 2017. This is a collaborative project involving both institutions (CNES, ONERA) and schools (ISAE, TELECOM Bretagne). The different equipments to qualify are the Supaero Star Tracker, which measures stars’ luminosity to infer the satellite’s attitude, a detector for particles trapped in the Earth magnetic field designed by the ONERA, and the AOCS. Uplink and Downlink communications will be provided during the mission by the HETE Primary Ground Stations. JUMPSAT is the first Cubesat which needs a three axis attitude control, which involves an innovative mission analysis, to overcome all these constraints. The mission analysis deals with the orbit’s determination, the Cubesat’s structure, the power strategy, and the visibility balance. The particles detector is the only constraint for the altitude of the satellite: we can get meaningful data only at altitudes higher than 700 km. Moreover, the most interesting zones are South Atlantic and poles. But a circular orbit with this altitude does not respect the LOS (French space act).The structure of the Cubesat is also hard to define. To get information from the satellite, we need an antenna, and an attitude and orbital control system to point the antenna at the ground station and the Star Tracker at the stars. Solar Panels cannot be opened out because of the micro elements that could be settled on the particles detector. However, fixed solar panels are not very efficient to recharge batteries. The power balance shows critical problems: both attitude control system and the Star Tracker consume a lot, and cannot work at the same time during the whole orbit. However, all the components are linked: the Star Tracker is not efficient if the satellite attitude is not stabilized; the antenna functioning must be synchronized with visibilities by the ground station. Anyway, the visibility balance stresses the point that a ground station at Toulouse would be particularly welcome. We need also to take into account phenomena of eclipse and satellite drift. To conclude, our mission analysis is deeply constrained by the equipments we want to qualify. Our task is to find the optimal orbit, suggest a power strategy considering the orbital constraints and components’ physical parameters, and to study the visibility balance. It is a real challenge in terms of power consumption, architecture, orbital strategy for such a small satellite

Development of Small-Scale and Low-Power Attitude Determination System for Nanoscale Satellites by Infrared Earth-Imaging Sensors

Many space missions require that the spacecraft be oriented in a specific direction to operate correctly. ARKSAT 1, the University of Arkansas’s first satellite, is a 1U CubeSat designed to perform atmospheric spectroscopy from Low-Earth Orbit and as such requires precise attitude determination and control. Currently, attitude determination systems for 1U CubeSats with small space, low power, and low cost restrictions do not exist. This paper discusses the development of an earth-imaging infrared camera system for attitude determination on CubeSats and SmallSats that meets these requirements. Melexis MLX 90640 IR arrays and Microchip 8-bit microcontrollers are used to create infrared images of various test targets. The contrast of the resulting images is discussed along with recommendations for future development of the system

Deploying quantum light sources on nanosatellites II: lessons and perspectives on CubeSat spacecraft

To enable space-based quantum key distribution proposals the Centre for Quantum Technologies is developing a source of entangled photons ruggedized to survive deployment in space and greatly miniaturised so that it conforms to the strict form factor and power requirements of a 1U CubeSat. The Small Photon Entangling Quantum System is an integrated instrument where the pump, photon pair source and detectors are combined within a single optical tray and electronics package that is no larger than 10 cm x 10 cm x 3 cm. This footprint enables the instrument to be placed onboard nanosatellites or the CubeLab structure aboard the International Space Station. We will discuss the challenges and future prospects of CubeSat-based missions.Comment: Submitted to SPIE Quantum Information Science and Technology. Paper number 9648-4

End to End Satellite Servicing and Space Debris Management

There is growing demand for satellite swarms and constellations for global positioning, remote sensing and relay communication in higher LEO orbits. This will result in many obsolete, damaged and abandoned satellites that will remain on-orbit beyond 25 years. These abandoned satellites and space debris maybe economically valuable orbital real-estate and resources that can be reused, repaired or upgraded for future use. Space traffic management is critical to repair damaged satellites, divert satellites into warehouse orbits and effectively de-orbit satellites and space debris that are beyond repair and salvage. Current methods for on-orbit capture, servicing and repair require a large service satellite. However, by accessing abandoned satellites and space debris, there is an inherent heightened risk of damage to a servicing spacecraft. Sending multiple small-robots with each robot specialized in a specific task is a credible alternative, as the system is simple and cost-effective and where loss of one or more robots does not end the mission. In this work, we outline an end to end multirobot system to capture damaged and abandoned spacecraft for salvaging, repair and for de-orbiting. We analyze the feasibility of sending multiple, decentralized robots that can work cooperatively to perform capture of the target satellite as a first step, followed by crawling onto damage satellites to perform detailed mapping. After obtaining a detailed map of the satellite, the robots will proceed to either repair and replace or dismantle components for salvage operations. Finally, the remaining components will be packaged with a de-orbit device for accelerated de-orbit.Comment: 13 pages, 10 figures, Space Traffic Management Conference. arXiv admin note: text overlap with arXiv:1809.02028, arXiv:1809.04459, arXiv:1901.0971