Technical Sessions

Session III: TidBits

Chair: Odile Clavier, Creare, Inc.

Tuesday, August 10, 2010

8:30 a.m.Novel Radiation Design Approach for CubeSat Based Missions

Justin Likar, Stephen Stone, Robert Lombardi – Lockheed Martin Space Systems; Kelly Long – Lockheed Martin Information and Global Services Enterprise Integration Group

ABSTRACT: Spacecraft design innovations enabled by nanosatellite, and CubeSat-based, missions often requires a greater-than-desirable amount of risk associated with space radiation design. The accelerating rate of technology advancement in this smaller form factor introduces more advanced / sensitive payloads wherefore a novel approach to radiation environment modeling and design is required in order to minimize risk associated with the development and deployment of advanced / strategic payloads. The space radiation dose to which spacecraft at Low Earth Orbit altitudes (for CubeSats typically 400 km to 800 km) are subjected is dominated by contributions from geomagnetically trapped protons (typical energy range 0.1 MeV to >100 MeV) and electrons (typical energy range 0.1 MeV to 6.0 MeV). The present paper describes a radiation design approach based upon commonly available design tools as well as proposes a novel mission concept, sufficiently executable via a low power 1U vehicle, for purposes of characterizing the anisotropic total radiation dose at Low Earth Orbit altitudes. Analyses and discussions summarized herein demonstrate the importance of focusing on accurate determination of the radiation environment in the presence of spacecraft structure.

8:45 a.m.Study of the Small: Potential for Operational Military Use of CubeSats

Chalie Galliand – United States Air Force

ABSTRACT: The DoD is known for looking to innovative thinking to provide answers to its warfighter’s needs. This holds very true in the realm of space based capabilities. Recently, the sizes of assets in space have been shrinking in size. However, their capabilities have been growing at an accelerated rate. CubeSats are quickly becoming an area of interest because of their growing potential to fulfill operational military missions.

9:00 a.m.Two CubeSats with Micro-Propulsion in the QB50 Satellite Network

P. P. Sundaramoorthy, E. Gill, C. J. M. Verhoeven, J. Bouwmeester – Delft University of Technology

ABSTRACT: A network of small low-cost satellites is the only realistic option for multi-point in-situ measurements in the lower thermosphere. The QB50 program, an initiative of the von Karman Institute of Fluid Dynamics (VKI), aims to employ a network of 50 CubeSats built by universities to study the lower thermosphere (90-320 km). All 50 CubeSats will carry identical sensors and will be launched together from a single launch vehicle. QB50 will also study the re-entry process by measuring a number of critical parameters during re-entry.

The Delft University of Technology (TUDelft) intends to provide two satellites out of the 50 CubeSats in the QB50 network. This paper will discuss the preliminary orbit analysis of the QB50 satellites that will allow a first order evaluation of mission performance parameters like lifetime and coverage. The paper will subsequently look at the two satellites provided by TUDelft, each of which is equipped with a highly miniaturized propulsion system in addition to the science payload. This scenario is an excellent opportunity to demonstrate relative motion control between two CubeSats and elevate university CubeSats as serious contenders for significant science missions. A first analysis assesses the possibility of drag compensation and differential drag compensation using the TUDelft satellites with micro-propulsion.

9:15 a.m.Coral: A High Performance Design Expanding CubeSat Mission Options

Steve Schenk – Comtech AeroAstro, Inc.; Robert Burt – Space Dynamics Laboratory

ABSTRACT: The Coral bus design meets the stringent pointing/slew requirements of Electro-Optical (EO) or Space Situational Awareness (SSA) missions, as well as the higher payload power requirements for Communications or Synthetic Aperture Radar (SAR) missions. The power design features two deployed solar array wings along with a Lithium-Ion battery that provides significant payload power during all mission timeframes. The Attitude Determination and Control Subsystem (ADCS) features excellent agility/stability performance and excellent pointing accuracy performance through the use of a Miniature Star Tracker (MST) developed by CAA. Coral’s Communications system features a high data rate transceiver for support to these specialized missions. Coral’s Avionics subsystem communicates over a high bandwidth, standardized bus that provides a number of external interface options to the payload. The Command and Data Handling (C&DH) software architecture allows rapid integration of any payload hardware or software option with little or no impact to the bus architecture design at any point within the program timeline. Coral facilitates rapid assembly and disassembly of the Coral spacecraft and provides clear access to external interfaces at all times. The Coral bus also provides the ability to be easily upgraded for additional capabilities (e.g., addition of propulsion and power, downlink, and encryption upgrades).

9:45 a.m.Huge Power Demand...Itsy-Bitsy Satellite: Solving the CubeSat Power Paradox

Craig Clark – Clyde Space Ltd

ABSTRACT: Payload developers are becoming increasingly aware of the benefits that very small spacecraft, such as CubeSats, can offer for fast turn-around, low-cost missions. This increased interest in CubeSats for commercial, military and scientific missions is resulting in some exciting and challenging applications for this miniature satellite platform. The challenges include the ability to realize fine attitude control, the need to overcome the physical challenge of payload accommodation, but most consistently, is the capacity to generate and store enough power on-board the spacecraft to fulfill the mission requirements. So how do we overcome the power problem on CubeSats?

Power provision on board any spacecraft is not simply about how large the solar arrays are - size helps, but it isn't everything - it is the configuration of the solar arrays, the efficiency and effectiveness of the power management system and the choice of battery technology that all combine to provide a power system that packs a punch on a tiny satellite. Through the use of a custom designed, CubeSat power analysis design tool, this paper evaluates some common and novel solar array configurations for typical CubeSat orbits. This included both body mounted and deployed solar panel approaches.

Having been asked recently, ‘Can I fit my LiDAR on a CubeSat platform?’, it is clear that power provision on CubeSats will continue to be a bottle neck for new CubeSat applications. This paper shows that CubeSats can provide surprisingly respectable peak and orbit average power levels when configured appropriately.

10:00 a.m.OLFAR, A Radio Telescope Based on Nano-Satellites in Moon Orbit

S. Engelen, C. J. M. Verhoeven – Delft University of Technology; M. J. Bentum – University of Twente

ABSTRACT: It seems very likely that missions with nano-satellites in professional scientific or commercial applications will not be single-satellite missions. Well structured formations or less structured swarms of nano-satellites will be able to perform tasks that cannot be done in the “traditional” way. The Dutch space-born radio telescope project OLFAR, the Orbiting Low Frequency Array, is a good example of a typical “swarm-task”. The OLFAR radio telescope will be composed of an antenna array based on nano-satellites orbiting the moon to shield the receiving nodes from terrestrial interference. The array will receive frequencies in a band from around 30 kHz to 30 MHz. This frequency band is scientifically very interesting, since it will be able to detect signals originating from the yet unseen “Dark Ages” ranging from the Big Bang until around 400 million year after. Another science driver is the LF activity from (exo) planets.

In this paper the design parameters for the satellites and the swarm will be given and status of the OLFAR project will be reported. Details will be given about the antenna system, the LF-receiver and the signals that are expected.

10:15 a.m.Dynamic Ionosphere CubeSat Experiment (DICE)

Geoff Crowley, Gary Bust – ASTRA; Chad Fish, Charles Swenson, Robert Burt, Tim Neilsen – Space Dynamics Laboratory; Aroh Barjatya – Embry-Riddle Aeronautical University; Miguel Larsen – Clemson University

ABSTRACT: The Dynamic Ionosphere Cubesat Experiment (DICE) mission has been selected for flight under the NSF "CubeSat-based Science Mission for Space Weather and Atmospheric Research" program. The mission has three scientific objectives: (1) Investigate the physical processes responsible for formation of the midlatitude ionospheric Storm Enhanced Density (SED) bulge in the noon to post-noon sector during magnetic storms; (2) Investigate the physical processes responsible for the formation of the SED plume at the base of the SED bulge and the transport of the high density SED plume across the magnetic pole; (3) Investigate the relationship between penetration electric fields and the formation and evolution of SED.

The mission consists of two identical Cubesats launched simultaneously. Each satellite carries a fixed-bias DC Langmuir Probe (DCP) to measure in-situ ionospheric plasma densities, and an Electric Field Probe (EFP) to measure DC and AC electric fields. These measurements will permit accurate identification of storm-time features such as the SED bulge and plume, together with simultaneous co-located electric field measurements which have previously been missing. The mission team combines expertise from ASTRA, Utah State University/Space Dynamics Laboratory (USU/SDL), Embry-Riddle Aeronautical University and Clemson University.

10:30 a.m.3D Printing and MEMS Propulsion for the RAMPART 2U CUBESAT

Gilbert Moore – Project Starshine; Walter Holemans – Planetary Systems Corporation; Adam Huang, John Lee, Matthew McMullen – The University of Arkansas; Jim White – Colorado Satellite Services; Robert Twiggs, Benjamin Malphrus, Nathan Fite – Morehead State University; David Klumpar, Ehson Mosleh, Keith Mashburn – Montana State University; David Wilt, James Lyke – Air Force Research Laboratory/Space Vehicles Directorate; Stewart Davis – CRP USA, LLC; Wes Bradley – Analytical Graphics, Inc.; 2ndLt Thomas Chiasson – United States Air Force; Jay Heberle – Universal Space Network; Pat Patterson – Space Dynamics Laboratory

ABSTRACT: A volunteer consortium of the individuals and organizations listed on the title page of this document is using rapid prototyping and MEMS technologies to design and build a 2U RAMPART CUBESAT (RApid prototyped Mems Propulsion And Radiation Test CUBEflow SATellite). The flight of this satellite is intended to certify warm gas propulsion subsystems and magnetic stabilization for Cubesat orbital altitude adjustment, as well as rapid prototyping methods of building one-piece satellite structures, propellant tanks, printed circuit board cages, erectable solar panels, antenna deployment mechanisms, etc. at a fraction of the cost of current methods. Design revisions are being accommodated with a minimum of effort, time and expense. New laser-sintered materials with improved mechanical and thermal properties are being adapted for space use from the Formula 1 Racing field. Polymer sealants and metal platings have been utilized on surfaces inside and outside the satellite to eliminate outgassing and to aid in thermal management. This paper describes the use of these techniques to design-print-fly a 2U Cubesat that will raise its own apogee altitude to 1200 km, just below the equatorial inner Van Allen Radiation Belt, following deployment from its launch vehicle into an initial 450km circular orbit with an inclination of 45 deg. The satellite will measure incident energetic particle flux, together with the performance of new, improved radiation-hardened Cubeflow components and circuits and high-performance solar cells and cover glasses in that enhanced radiation environment, and telemeter those measurements to a redundant international ground station network.

Alternate An Optical Payload for CubeSats

Seshupriya Alluru, Janise McNair – University of Florida

ABSTRACT: Optical wireless communications provide a promising, high bandwidth alternative to radio communications, where high performance links are desired. For large satellites (say, wet mass>1000kg), laser cross links have been successfully established since 2001 by various space agencies in Europe and Japan. Thus far, the cross-links have been able to achiever data rates in Gbps range for distances greater than 10,000km. Such gains would be monumental improvement for communications in small satellite domain (say, wet mass for Cubesats >10kg), where the typical communications payload users radio antenna that achieve an average data rate of 10kpbps.This paper proposes a promising laser communication system for CubeSat. First, a study of the laser crosslink system of large satellites is provided. Then, the subsystems of the larger satellite laser communications are analyzed for suitability in the CubesSat frame. Each subsystem is further analyzed in terms of functionality, contribution to the weight of the optical payload and power requirements. The parameters of the larger system are then redesigned to meet the size, weight and power constraints of the CubeSat. The new system is simulated for performance and various candidate scenarios are discussed.

Alternate Composite and PCB Based Implementations of a Solar Panel Design for SwampSat

Sharan Asundi, Matthew Mahin, Vivek Nagabhushan, Tzu Yu Lin, Norman Fitz-Coy – University of Florida

ABSTRACT: A multifunctional solar panel design is implemented as (i) carbon fiber composite panel and (ii) printed circuit board (PCB) for SwampSat, a University of Florida CubeSat. The solar panels structurally support SwampSat and accommodate embedded magnetic coils, a surface suitable for mounting solar cells, Sun sensor mounting and circuitry for sun sensors, solar cells, temperature sensors and magnetic coils. Wet layup technique, used for the development of carbon fiber composite panels with embedded magnetic coils and the vacuum bagging procedure to cure the panels are discussed. The implementation as a multi-layered PCB to accommodate 2oz per square foot copper traces as magnetic coils, copper deposits for mounting solar cells and circuitry and connectors for panel components is discussed. The paper discusses the design, development, lessons learned as well as the pros and cons of each implementation. Prototypes of fully functional panels are presented. Results of thermal-vacuum and vibration tests performed on the PCB panel are discussed.