Technical Sessions

Session III: Mission Payloads

Chair: Hallie Walden, Ball Aerospace

Tuesday, August 11, 2009

8:45 a.m. STEIN (SupraThermal Electrons, Ions and Neutrals), A New Particle Detection Instrument for Space Weather Research with CubeSats

D.L. Glaser, J.S. Halekas, P. Turin, D.W. Curtis, D.E. Larson, S.E. McBride, R. P. Lin – Space Sciences Laboratory, University of California at Berkeley

ABSTRACT: The Space Sciences Laboratory at UC Berkeley is proposing a 3U CubeSat mission, the CubeSat for Ions, Neutrals, Electrons, and Magnetic fields (CINEMA), to be funded by the NSF Space Weather CubeSat program and Kyung Hee University, S. Korea. CINEMA will have a particle detector called STEIN (SupraThermal Electrons, Ions, and Neutrals), part of a new breed of highly capable, low mass, and low power consumption silicon semiconductor detectors (SSDs). STEIN will measure particles in the ~2‐100 keV range and distinguish between electrons, ions and neutrals up to ~20 keV. It will perform fundamental research on magnetic storms and the storm‐time ring current, charged particle precipitation, and electron microbursts. STEIN separates electrons, ions, and neutral atoms with an electrostatic deflection system. It has analog electronics with a very low energy threshold and a mechanical attenuator that lowers the particle count by 10². Using a data decimation scheme and the attenuator, STEIN can measure particle fluxes as high as 10⁸ (cm² s sr keV)^‐1. Preliminary tests of a prototype indicate that the electrostatic deflection system works as expected. After a complete set of tests, a flight version of the instrument will be assembled, in anticipation of a possible launch in 2011.

9:00 a.m. A GPS Bistatic Radar for Small Satellite Applications

James Pogemiller, Chen‐Chi Chu, Demoz Gebre‐Egziabher – University of Minnesota

ABSTRACT:This paper presents the results of analysis and experiments evaluating the potential for using reflected GPS signals as a remote sensing instrument. Using GPS signals in this manner is, in effect, GPS bistatic radar and has many advantages for small satellite applications because it provides a sensor which is passive, has a small foot print and consumes very little power. The reflected GPS signals can provide information about ocean surface conditions and other information about terrestrial land mass. The GPS bistatic radar also has the potential for being a sensor for relative ranging and proximity sensing on orbit. This is particularly useful because it allows measuring ranges to objects or satellites that are not equipped with a GPS receiver (e.g, a dead satellite or passive target).

9:15 a.m. Affordable SAR Constellations to Support Homeland Security

Adam Baker, Rachel Bird, Stuart Eves – Surrey Satellite Technology Ltd./Surrey Space Centre; Brent Abbott – Surrey Satellite Technology US LLC

ABSTRACT:This paper describes the applications, benefits and customers for synthetic aperture radar (SAR) payloads carried on small low cost space missions. Although numerous current and soon‐to‐launch carry SAR, affordability of such missions to serve particular types of customers is poor. This is in part due to the high cost of SAR payloads, and specific needs such as high power drain and support for large, heavy antennae which have mandated large, costly satellites. The paper explores the trade‐space between application, customer and performance to show how there is a market for a Disaster Monitoring Constellation class SAR, or DMC‐SAR which can support a number of unmet needs in the Earth observation sector. A DMC‐SAR mission is shown to be feasible, with various options for sourcing and mating the critical SAR instrument to a small low cost SSTL bus. A price of $50M for such a mission is justified from a bottom up system engineering perspective and a top‐down business case driven approach. The value proposition offered by a constellation of DMC‐SAR spacecraft is global imagery with a daily revisit, unaffected by weather, day / night operation, with a system robustness far in excess of a single large satellite, and at a price point that allows potential data sales revenue to more than offset the price of the system.

9:30 a.m. Big Astrophysics in a Small Package – The Gravity & Extreme Magnetism SMEX (GEMS) Mission

Erin Walter, Carlos Niederstrasser – Orbital Sciences Corporation USA; Jean Swank, Keith Jahoda – NASA Goddard Space Flight Center

ABSTRACT:The Gravity and Extreme Magnetism SMEX (GEMS) mission will be the first mission to use x‐ray polarimetry to characterize the geometry and behavior of x‐ray sources, including supermassive black holes and magnetars. Although such astrophysics missions usually require a “large” spacecraft, recent advances in technology allow a smaller spacecraft to conduct significant science in this exciting field. By focusing on the polarization of x‐rays, GEMS will enable scientists for the first time to answer some of the most exciting questions in astrophysics. Polarization has the potential to resolve conflicting estimates of black hole spin, reveal how energy is released in this environment, and probe the physics behind strong magnetic fields.

GEMS is made possible by recent breakthroughs in several key technologies. Advances in gas detector echnology have enabled exploitation of photoelectric polarimetry, without sacrificing sensitivity. Light‐weight mirrors are constructed of especially treated aluminum foils. A deployable boom provides the appropriate separation between the detectors and the mirrors. GEMS has three telescopes on one spacecraft increasing the effective collection area compared to one large telescope. It is the small dimensions and mass of the telescopes and the deployable boom that permits the mounting of three telescopes and vehicle rotation, while retaining a small overall observatory size. Supporting the instrument is the LEOStar 2/750 spacecraft bus.

9:45 a.m. Compact Dual Field‐of‐View Telescope for Small Satellite Payloads

James Peterson, Trent Newswander – Space Dynamics Laboratory

ABSTRACT:Small satellite payloads commonly involve missions with multiple field‐of‐view (FOV) capability. For these missions, it is often desirable that the payload instrument contain optical sensors with both a wide FOV for searching or scanning a scene and a narrow FOV to interrogate and identify the object of interest. This generally requires multiple sensors or a zoom lens with multiple moving lenses. For infrared sensors, these approaches are generally not compact enough for use on small space platforms, unmanned air vehicles, or small satellite payloads. This paper describes a compact dual field‐of‐view telescope with a 6x field ratio. The selection of the field involves changing optical filters, which transmit different spectral wavebands. Each spectral waveband is associated with separate optical paths with differing focal lengths, thus fields‐of‐view. This concept has been proven through the design, build, and alignment of a long‐wave infrared (LWIR) catadioptric telescope.

10:00 a.m.The Cibola Flight Experiment

Michael Caffrey, Kim Katko, Anthony Nelson, Joseph Palmer, Scott Robinson, Diane Roussel‐Dupre, Anthony Salazar – Los Alamos National Laboratory; Michael Wirthlin, William Howes, Daniel Richins – Brigham Young University

ABSTRACT:The Cibola Flight Experiment (CFE) is an experimental small satellite carrying a reconfigurable processing instrument developed at the Los Alamos National Laboratory that demonstrates the feasibility of using FPGA‐based high‐performance computing for sensor processing in the space environment. The CFE satellite was launched on March 8, 2007 in low‐earth orbit and has operated extremely well since its deployment. The nine Xilinx Virtex FPGAs used in the payload have been used for several high‐throughput sensor processing applications and for single‐event upset (SEU) monitoring and mitigation. This paper will describe the CFE system and summarize its operational results. In addition, this paper will describe the results from several SEU detection circuits that were performed on the spacecraft.

Alternate  Operational Class Smallsat System for Sub&‐Metre Resolution Imaging

Maarten Meerman, George Tyc, Tim Butlin, Wade Larson – MDA; Nick Waltham, Nigel Morris – Rutherford Appleton Laboratory

ABSTRACT:MDA, together with its UK partner RAL, has been developing its next generation of operational class smallsat submeter imaging systems. This development will provide an operational half‐meter class solution with long lifetime and world class image quality at a dramatically reduced price point. To achieve this, MDA is leveraging heavily from the recently launched RADARSAT‐2 and RapidEye missions, and also from the technology developed for the Topsat mission launched in 2005. The system contains a number of innovations that are in the process of being patented.

This paper describes the unique camera and associated satellite design that is under development to provide 0.5 m GSD from 500 km altitude. This includes an Active On‐Orbit Optics (AO3) system to actively align the optics in space, and a jitter suppression system. The spacecraft bus is configured around the camera to make it compact, while providing easy access to the subsystems. Its size allows it to be launched on low cost launch vehicles, either single or a constellation. Its small size provides for high agility using conventional low‐cost reaction wheels. MDA’s experience in the ground systems for sub‐meter class images for both DigitalGlobe and GeoEye ensures that the system will provide exceptional image quality.

Alternate  Compact Optical Payload for Daily Survey of Vegetation from Small Satellites

Luca Maresi, Matteo Taccola – European Space Agency; Wouter Moelans – OIP Sensor Systems; Vincent Moreau – AMOS; JanVermeiren – XenICs

ABSTRACT:Recent advancement of optics fabrication, metrology and detectors are the basis for the development of a new compact instrument designed to provide daily revisit for the analysis of vegetation. The instrument has been optimized to improve multispectral imaging capabilities with respect to Spot‐Vegetation, while minimizing mass and power to be accommodated on a small satellite. The new technologies used for this instrument allow shrinking the mass and reducing the power consumption of a factor 5 with respect to Spot‐Vegetation. The new instrument is designed to fly on Proba‐V, a small satellite developed to ensure continuation of the Spot‐Vegetation products.

The paper gives an overview of the payload, presents its performance and explains which innovations allow a very compact design. In particular, the paper presents the technology used for the fabrication of mirrors, the approach used for their alignment, and the tests results obtained so far on the first prototype of the telescope. A section of the paper describes the InGaAs detector developed for the SWIR channel, a long linear array able to operate uncooled. The paper concludes with a description of the mission, of the payload accommodation on the small satellite, and of the data produced.