All 2010 Content

UNESCOsat: The United Nations’ First Satellite

Donald Platt — Thu, 12 Aug 2010 12:45:00 PDT

An international effort is underway to produce the first satellite in the history of the United Nations. The idea of the preparation and launch, with the endorsement of the UNESCO branch of the United Nations, of an international satellite to promote science education, public awareness of science, and international co-operation in the basic sciences, was presented by the National Commission of the Russian Federation for UNESCO to the UNESCO basic sciences committee. The General Conference of UNESCO at its 35th session in October 2009 approved an amendment to the UNESCO draft Programme and Budget for 2010-2011 concerning the project. The launch vehicle and a 100 kilogram satellite platform will be provided by Russia. Payloads will be provided on the basis of international cooperation including several from American universities. Available payload mass is approximately 30kg. Anticipated goals of the project include opportunities to inform and inspire younger students and the public about space missions and the benefits they bring to the world; assist in science technology, engineering and mathematics (STEM) education in the developing world; provide international student payload opportunities; and to highlight the benefits and importance of satellites and space for the general public. Student groups are being sought from around the world to assist in developing payloads, education programs, developing ground stations and other associated areas. One payload, defined thus far, is a remote sensing system to assist students in understanding resource management, science opportunities from space and crop health in their own regions of the world. Images will be able to be requested by participating student groups and then downloaded by their own ground stations or the internet. These images can be used both for educational programs and also to assist in food production and Earth resource management locally. Activities to provide information on the project to a wide range of institutions, partner organizations and sponsoring agencies that may be interested in cooperation are currently underway. A second payload will be a microbial experiment to subject extremophiles to the environment of space and determine their viability.

Conducting Science with a CubeSat: The Colorado Student Space Weather Experiment

Scott Palo et al. — Thu, 12 Aug 2010 12:30:00 PDT

Energetic particles, electrons and protons either directly associated with solar flares or trapped in the terrestrial radiation belt, have a profound space weather impact. A 3U CubeSat mission with a single instrument, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), has been selected by the National Science Foundation to address fundamental questions pertaining to the relationship between solar flares and energetic particles. These questions include the acceleration and loss mechanisms of outer radiation belt electrons. The Colorado Student Space Weather Experiment operating in a highly inclined low earth orbit, will measure differential fluxes of relativistic electrons in the energy range of 0.5-2.9 MeV and protons in 10-40 MeV. This project is a collaborative effort between the Laboratory for Atmospheric and Space Physics and the Department of Aerospace Engineering Sciences at the University of Colorado, which includes the integration of students, faculty, and professional engineers.

The FASTRAC Experience: A Student Run Nanosatellite Program

Sebastián Muñoz et al. — Thu, 12 Aug 2010 12:15:00 PDT

The FASTRAC (Formation Autonomy Spacecraft with Thrust, Relnav, Attitude and Crosslink) satellites built by students from The University of Texas at Austin are manifested for a Space Test Program (STP) launch in September 2010. FASTRAC is the 2005 winner of the University Nanosatellite competition sponsored by the Air Force Office of Space Research and Air Force Research Laboratories. FASTRAC is a two nanosatellite mission that will be launched aboard a Minotaur IV rocket from Kodiak, Alaska. The goal of the FASTRAC mission is to demonstrate enabling technologies for nanosatellites that work together in space. The primary mission objectives are: 1) demonstrate two-way intersatellite crosslink with verified data exchange, 2) perform on-orbit real-time GPS relative navigation between satellites, and 3) demonstrate autonomous thruster operation using single-antenna on-orbit real-time GPS attitude determination. A description of the FASTRAC mission and its concept of operations are provided. This paper also recounts the history of the FASTRAC program, from its beginning in 2003 as an entry in the University Nanosatellite Program (UNP-3) Competition until its Launch and Operations Phase in 2010. Some of the unique goals and challenges of building, testing, delivering, and operating a nanosatellite in a university environment with a very limited budget are addressed. Lessons learned throughout the project's life cycle and recommendations for similar programs are documented and shared.

Experimental Characterization of a Radio Frequency Microthermal Thruster

Shae Williams et al. — Thu, 12 Aug 2010 12:00:00 PDT

In this paper, the results of the first experimental tests on an RF (Radio Frequency) microthermal propulsion system are reported. A brief synopsis of existing propulsion systems for the 10-100 micronewton thrust regime suitable for microsatellites is presented, with cold gas thrusters the currently dominant option due to their reliability, low weight and volume requirements, and lack of complexity. RF microthermal thrusters are also low-requirement compared to most candidate propulsion subsystems, operate on well-understood theoretical principles, and in testing with argon have demonstrated specific impulses as high as 80-85 seconds with a suboptimal propellant and geometry, implying a higher ultimate performance is attainable. Performance is shown to depend linearly on power input, but that performance improves significantly at lower mass flow rates around 0.1 mg/s. Further, the frequency of the RF voltage applied across the coaxial electrodes has a large and nonlinear effect on performance. These trends will both be studied further in later research.

Miniature Wire Boom System for Nano Satellites

Steven Grover et al. — Thu, 12 Aug 2010 11:45:00 PDT

An overview of a 10 meter (tip-to-tip) system for deploying four 1-cm spherical sensors is presented. These sensors permit the measurement of the two-dimensional DC-electric field. The mechanism which deploys the sensors consists of a spool of wire with a small, non-magnetic, piezoelectric motor for deployment control. The entire wire boom system is 1.25 cm high and can fit in a standard CubeSat. A mockup satellite has been developed that mimics the dynamics of a spinning CubeSat as the booms are deployed. This platform contains a 3-axis magnetometer and a set of accelerometers for studying the dynamics of the deployment. Deployment tests in a 1-g field are presented. This mechanism will be flown on the NSF sponsored DICE mission.

Small Satellites Technologies from Newcomers Perspective – Slovenian Space-Si Case

Rodič Tomaž et al. — Thu, 12 Aug 2010 11:30:00 PDT

In Slovenia a new Centre of Excellence for Space Sciences and Technologies SPACE-SI became operational in 2010. The RTD goals of the SPACE-SI consortium consisting of academic institutions, high-tech SMEs and large industrial and insurance companies are focused on nano and micro satellite technologies that are enabling high precision interactive remote sensing and precise maneuvering of small spacecraft in formation flying missions. For the development of these technologies an advanced RTD infrastructure will be set up including a multidisciplinary laboratory for closed loop investigations of materials, structures, micropropulsion systems, electronic components and visual based control algorithms in simulated space environments. The experimental techniques will be combined with virtual models for primal and sensitivity analyses of components, subsystems and platforms as well as for their characterisation by inverse numerical analyses and optimisation of their design with respect to performance and reliability. A development of a technology demonstration mission, which will include the testing of a ferroelectric frequency and polarization tunable microstrip patch design antenna and automatic feature recognition systems for interactive earth observation as well as advanced micropropulsion for precise maneuvering in formation flights, is envisaged for which synergies and partners are sought at the international level.

The QB50 Program, the First CubeSat Constellations Doing Science

Robert Twiggs et al. — Thu, 12 Aug 2010 11:15:00 PDT

The QB50 program was originated by Jean Muytaert at the von Karman Institute in Brussels, Belgium. Through the VKI efforts are underway to provide launches for 50 university built 2U CubeSats. These CubeSats will be provided by an international group of universities of which 10 CubeSats will be provided by US universities. The instruments will be provided by the science community. The expected launch attitude is to be between 300km-325km and during the short lifetime will make atmospheric measure-ments of the Ignorsphere (that part of the atmosphere that the atmospheric scientist say has been ignored due to a lack of sufficient measurements to effect-ively study it). This paper will outline the proposed method used to select US universities to participate and other aspects of the mission to be launched in 2013.

Inkjet-Printed Transparent Antennas Integrated on Solar Cells

Tursunjan Yasin et al. — Thu, 12 Aug 2010 11:00:00 PDT

This paper presents the experimental study on an optimal circular meshed patch antenna inkjet-printed on transparent substrate. Meshed patch antennas provide a cost-effective solution for applications where the antennas need to be optically transparent. An earlier study has shown that it is feasible to integrate a rectangular meshed patch antenna with 93% transparency directly on solar cells. Although circular meshed patch antennas are as important as the rectangular ones, the study on the subject is rather limited due to the limit in fabrication method and lack of an effective feeding method. This paper focuses on the feed design and fast-prototyping with inkjet printing technique, where the antenna geometry is printed on a thin transparent substrate with conductive ink using a commercial printer. The transparent substrate can then be integrated on solar cells. It is found that a non-contact feed using coupling between the feed line and the antenna is more effective and realistic than other feeding methods for solar cell integration. Although the design approach is tested with inkjet printed prototype, it is highly feasible that one can print meshed circular antennas directly on substrates such as cover glass of solar cells.

Initial Flight Results for an Automated Satellite Beacon Health Monitoring Network

Anthony Young et al. — Thu, 12 Aug 2010 10:45:00 PDT

Beacon monitoring is an automated satellite health monitoring architecture that combines telemetry analysis, periodic low data rate message broadcasts by a spacecraft, and automated ground reception and data handling in order to implement a cost-effective anomaly detection and notification capability for spacecraft missions. Over the past two decades, this architecture has been explored and prototyped for a range of spacecraft mission classes to include use on NASA deep space probes, military spacecraft and small satellites. This previous work has also included formalization of performance assessment metrics to capture the cost and performance of the anomaly detection and notification tasks, thereby allowing a characterization of the suitability of beacon monitoring implementations for specific missions. In this paper, we describe a newly implemented beacon architectre that has been developed and commissioned for operation in support of several NASA and university-class small spacecraft. The architecture consists of a spacecraft with a beacon transmission system, a network of four automated receive-only communications stations installed across the United States. Internet-based ground segment communications allowing centralized processing and logging of all received beacon messages, and a notification service for alerting on-call operators to anomalous conditions. We also present initial operational results for the network as applied to the NASA GeneSat-1 spacecraft, which has been operated by Santa Clara University students since its launch in December 2006. Finally, we describe future adaptations that are planned for this system given its pending use in supporting two additional NASA spacecraft due to be launched later in 2010. To the authors' knowledge, this is the first example of an operational satellite beacon-based health monitoring network.

Optical Networking for Aerospace Systems Provisioned through Plug-and-play Avionics

Keith Avery et al. — Thu, 12 Aug 2010 09:59:59 PDT

A high performance extension of the space plug-and-play avionics (SPA) technology is described based on the addition of optical fiber interconnection. This optical SPA (“SPA-O”), due to the bandwidth potential, provides the possibility of moving unprecedented amounts of data and rendering super-computing systems rapidly in orbital platforms. By exploiting the ideas of SPA, the optical properties of SPA-O components can be added to electronic datasheets embedded within the component so that the system-at-large can discover these components and exploit them in dynamically provisionable optical networks formed on demand.