Technical Sessions

Session IV: Recent and Future Missions

Chair: Carlos Neiderstrasser, Orbital

Tuesday, August 11, 2009

10:45 a.m.Blue Marble: Remote Characterization of Habitable Planets

Neville Woolf – University of Arizona; Brian Lewis – The Aerospace Corporation; James Chartres, Anthony Genova – NASA Ames Research Center

ABSTRACT: The study of the nature and distribution of habitable environments beyond the Solar System is a key area for Astrobiology research. At the present time, our Earth is the only habitable planet that can be characterized in the same way that we might characterize planets beyond the Solar System. Due to limitations in our current and near‐future technology, it is likely that extra‐solar planets will only be observed as single‐pixel objects. To understand this data, we must develop skills in analyzing and interpreting the radiation obtained from a single pixel. These skills must include the study of the time variation of the radiation, and the range of its photometric, spectroscopic and polarimetric properties. In addition, to understand whether we are properly analyzing the single pixel data, we need to compare it with a ground truth of modest resolution images in key spectral bands. This paper discusses the concept for a mission called Blue Marble that would obtain data of the Earth using a combination of spectropolarimetry, spectrophotometry, and selected band imaging. To obtain imagery of the proper resolution, it is desirable to place the Blue Marble spacecraft no closer than the outer region of cis‐lunar space. This paper explores a conceptual mission design that takes advantage of low‐cost launchers, spacecraft bus designs and mission elements to provide a cost‐effective observing platform located at one of the triangular Earth‐Moon Lagrangian points (L₄, L₅). The mission design allows for the development and use of novel technologies, such as a spinning Moon sensor for attitude control, and leverages lessons‐learned from previous low‐cost spacecraft such as Lunar Prospector to yield a low‐risk mission concept.

11:00 a.m.System Outline of Small Standard Bus and ASNARO Spacecraft

Toshiaki Ogawa – NEC Corporation; Keita Miyazaki – Institute for Unmanned Space Experiment Free Flyer (USEF); Osamu Itoh – New Energy and Industrial Technology Development Organization (NEDO)

ABSTRACT: ASNARO (Advanced Satellite with New system ARchitecture for Observation) system outline including payload characteristics and bus architecture is presented in this paper. ASNARO, which is being developed by NEC and USEF under the contract with NEDO, is a LEO satellite for the earth observation by optical sensor in sub‐meter class. The bus module of the ASNARO is highly adaptive for various missions such as remote sensing by optical sensor or Synthetic Aperture Radar (SAR) sensor, and for the future small satellite market. ASNARO imaging capability of Ground Sample Distance (GSD) from 504km altitude is less than 0.5m for the panchromatic band. The new silicon carbide mirror, named NTSIC, is employed for the primary mirror of the telescope.

11:15 a.m.Small Satellite Rendezvous and Characterization of Asteroid 99942 Apophis

James Chartres – Carnegie Mellon University/NASA Ames Research Center; David Dunham, Bobby Williams – KinetX, Inc.; Anthony Genova, Anthony Colaprete, Ronald Johnson, Belgacem Jaroux – NASA Ames Research Center

ABSTRACT: The Measurement and Analysis of Apophis Trajectory (MAAT) concept study investigated a low‐cost characterization mission to the asteroid 99942 Apophis that leverage small spacecraft architectures and technologies. The mission goals were to perform physical characterization and improve the orbital model. The MAAT mission uses a small spacecraft free flyer and a bi‐propellant transfer stage that can be incorporated as a secondary payload on Evolved Expendable Launch Vehicles (EELVs), Atlas V or Delta IV launches. Using the innovative secondary architecture allows the system to be launched on numerous GTO or LTO opportunities such as NASA science missions or commercial communication satellites. The trajectory takes advantage of the reduced Delta‐V requirement during the 2012‐ 2015 time frame, with a large flexible launch opportunity, from January to November 2012 and heliocentric injection occurs in April 2013. Primary communications use the traditional Deep Space Network (DSN) with a secondary system using a laser link demonstrating the technology at greater than Earth‐Moon distances. The spacecraft uses Commercial Off The Shelf (COTS) components and technologies in combination with a reduced Lunar CRater Observation and Sensing Satellite (LCROSS) instrument suite.The suite includes a high‐resolution navigation camera, two visible mapping cameras, an infrared camera and a laser ranger. The study of both the physical and dynamical properties of Apophis requires a rendezvous mission, with the spacecraft operating for several months in close proximity. Physical characterization occurs over three months and includes determining the mass, density, dynamical state, topography, and geological context of the object that is difficult to determine or cannot be determined from ground based instruments. Tracking of the spacecraft over several months using the Deep Space Network (DSN) ensures increased accuracy in orbit determination and combined with physical characterization allows for the study of non‐gravitational forces, such as the Yarkovsky effect. The science data and analysis can yield physical and orbital characteristics of Apophis several orders of magnitude better than currently estimated and provide science data that cannot be achieved with ground‐based instruments.

11:30 a.m.BX‐1: The Companion Microsatellite in Shenzhou‐7 Mission

Zhencai Zhu, Hongyu Chen, Wen Chen, Yilin Zhou, Yong Yu, Caixia Cao – Chinese Academy of Sciences

ABSTRACT: Microsatellites flying around big spacecraft can provide security monitoring for spacecrafts, extend mission functions, and provide an ideal platform for demonstrating and verifying key technologies of coordinated space missions. Most companion satellites have orbit manoeuvre capability. They usually take space station, aircraft, piloted spaceship, big satellite or other big spacecraft as task centre or service object, and fly with it in a certain relative formation. The BX‐1 micro‐satellite is the companion satellite for the Shenzhou VII (SZ‐7) manned spaceship and carries out two in‐orbit experiments in the Shenzhou VII mission: images capturing of SZ‐7 and the companion flying experiment. The release of BX‐1 from SZ‐7 was successful, which verifies the safety design of satellite release in orbit. The observation of SZ‐7 spaceship from space was achieved by BX‐1 after it was released. Images captured by the double‐focusing system provide for the first time the high resolution photos of the spaceship at a distance from about 4 metres to 8 km. After astronauts returned to the ground, BX‐1 continues its mission by conducting companion flying around the orbital module of SZ‐7 remained in the orbit, which successfully demonstrates the companion flying technologies of BX‐1. In this paper, we give comprehensive information about the BX‐1 satellite and introduce the in‐orbit experiments of BX‐1 in the Shenzhou‐7 mission with flight datum.

11:45 a.m.Spin Dynamics of the Pico Satellite Solar Cell Testbed Spacecraft

Siegfried Janson, David Hinkley – The Aerospace Corporation

ABSTRACT: The low Earth orbit (LEO) Pico Satellite Solar Cell Testbed spacecraft (PSSCT; also known as the PSSC Testbed) was ejected from the Space Shuttle Endeavour at 12:34 PM, PST, on November 29, 2008. The LEO PSSCT is a 6.5‐kg mass, 5” x 5” x 10”, fairly rigid, box‐shaped nanosatellite designed to provide space flight data on radiation degradation of multi‐junction solar cells. The LEO PSSCT was ejected from the shuttle with the long axis (Z axis) perpendicular to the instantaneous sun‐spacecraft line. It has an internal momentum wheel that was spun up before ejection, thus determining the angular momentum vector in inertial space. After ejection, the momentum wheel took 5 minutes to slow down, thus imparting a 507 degree/second rotation rate for the spacecraft body about the Z axis. MEMS rate gyros from Analog Devices were used to monitor the rotation rates about the X, Y, and Z axes, with Earth and sun sensors providing additional information for on‐orbit spin rate calibration. The Z axis has the minimum moment‐of‐inertia, so we expected the spacecraft to transfer energy from the Z axis to the X and Y axes over the course of several months. We obtained over three months of on‐orbit spin rate data.

12:00 p.m.Canadian Advanced Nanospace Experiment 2 Orbit Operations: One Year of Pushing the Nanosatellite Performance Envelope

Karan Sarda, Cordell Grant, Stuart Eagleson, Daniel Kekez, Amee Shah, Robert Zee – Space Flight Laboratory/University of Toronto

ABSTRACT: The objective of the Canadian Advanced Nanospace eXperiment (CanX) program is to develop highly capable nanospacecraft, i.e. spacecraft under 10 kilograms, in short timeframes of 2‐3 years. CanX missions offer low‐cost and rapid access to space for scientists, technology developers and operationally‐responsive missions. The Space Flight Laboratory (SFL), at the University of Toronto Institute for Aerospace Studies (UTIAS) has developed the CanX‐2 nanosatellite that launched in April 2008. CanX‐2, a 3.5‐kg, 10 x 10 x 34 cm satellite, features a collection of scientific and engineering payloads that push the envelope of capability for this class of spacecraft. The primary mission of CanX‐2 is to test and demonstrate several enabling technologies for precise formation flight. These technologies include a custom cold‐gas propulsion system, a 30 mN·m·s nanosatellite reaction wheel as part of a three‐axis stabilized Y thomson‐configuration attitude control subsystem, and a commercially available GPS receiver. The secondary objective of CanX‐2 is to perform a number of university experiments including an atmospheric spectrometer. After one successful year in orbit, the nanosatellite has met or exceeded all mission objectives and continues to demonstrate the cost‐effective capabilities of this class of spacecraft. Key achievement s to date include a characterization of the propulsion system, a full demonstration of the attitude determination and control subsystem including capabilities in accurate payload pointing (including nadir‐tracking) and orbit‐normal alignment, long‐duration reaction wheel operation, unprecedented radio performance for an operational nanosatellite, and successful science operations. The mission, the engineering and scientific payloads, and a discussion of notable orbit achievements and experiences of CanX‐2 are presented in this paper.

12:15 p.m.Delfi‐C³ Preliminary Mission Results

Robbert Hamann, Jasper Bouwmeester, Geert Brouwer – Delft University of Technology

ABSTRACT: Delfi‐C³ is a three‐unit CubeSat launched on April 28th 2008 and has been designed, developed and operated by students of the Delft University of Technology and several Engineering Colleges in the Netherlands. Preliminary results of the Thin Film Solar Cell and Autonomous Wireless Sun Sensor payloads are shown and discussed, as well as the experiences with a third on‐board experiment: a transponder for the radio amateur community.

In the first three months of operations Delfi‐C³ has collected 53,000 high quality current‐voltage curves of the solar cells (1.3% of the maximum possible) and has performed some 3,500 attitude measurements with the Sun sensor. These data have been collected by a worldwide network of radio amateurs, and have been sent to Delft for further processing. The relatively low yield is caused by a combination of a non‐uniform distribution of radio amateurs over the Earth’s surface and a design flaw in the Command and Data Handling Subsystem that caused unwarranted recovery actions by the computer watchdog function. The performance of the Attitude Determination and Control Subsystem and the Ground System is shortly discussed as far as they have had an impact on the quantity and quality of the payload data.

Although the mission results are satisfactory, not everything went as foreseen. Some design errors and project management shortcomings became evident prior and during operations. Recovery actions are outlined and lessons learned discussed. Special attention will be paid to the specific constraints related to developing and operating a satellite in an academic environment.

Delfi‐C³ is functioning well, and has entered its second period of scientific data collection after having completed a first three‐month period in Science Mode and some three months in Transponder Mode.

12:30 p.m.RapidEye System Commissioning and On‐Orbit Performance

Daniel Schulten, George Tyc, Yolanda Brown, Joe Steyn, Norman Hannaford, Wade Larson – MDA

ABSTRACT: RapidEye is a complete end‐to‐end commercial earth observation system comprising a constellation of 5 small satellites, each with a 5 band multi‐spectral camera providing 6.5 m GSD and an approximate 78 km swath, a dedicated Spacecraft Control Center (SCC), a data downlink ground station service, and a full ground segment designed to plan, acquire and process millions of square kilometres of imagery every day to generate unique land information products. The system is owned and operated by RapidEye AG, a commercial company providing global geo‐information services and data, located in Brandenburg, Germany. MDA is the mission prime contractor and was responsible for the delivery of the space and ground segments, launch of the constellation, and on‐orbit commissioning and camera calibration.

On August 29, 2008, the RapidEye constellation was successfully launched. Spacecraft and ground segment commissioning have taken place, and since 30 January 2009, RapidEye AG has taken control of the constellation to begin full commercial operations. The overall RapidEye system is performing well and is capable of collecting more than 4 M km² of high quality multi‐spectral imagery every day and can acquire an image of any location on earth every single day. The paper describes the overall system commissioning activities that were undertaken and provides a summary of the actual in‐orbit performance of the constellation and the system as a whole.

Alternate  Initial Flight Results from the PharmaSat Biological Microsatellite Mission

Christopher Kitts, Karolyn Ronzano, Richard Rasay, Ignacio Mas, Jose Acain, Michael Neumann, Laura Bica, Paul Mahacek, Giovanni Minelli, Erin Beck, Steve Li, Brian Gamp, Seamus Agnew, John Shepard – Robotic Systems Laboratory/Santa Clara University; John Hines, Elwood Agasid, Charlie Friedericks, Matthew Piccini, Macarena Parra, Linda Timucin, C. Beasley, Mike Henschke, Ed Luzzi, Nghia Mai, Mike McIntyre, Robert Ricks, Antonio Ricco, David Squires, Bruce Yost, Greg Defouw, Aaron Schooley, Diana Ly, Millan Diaz‐Aguado, Eric Stackpole, Orlando Diaz, Tammy Doukas – NASA Ames Research Center; David Niesel, Michael McGinnis – The University of Texas Medical Branch

ABSTRACT: The mission of the PharmaSat biological microsatellite is to investigate the efficacy of anti‐fungal agents in the spaceflight environment. The satellite uses autonomous, in situ bio‐analytical and sample management technologies in order to culture and characterize the growth of multiple samples of yeast, which are exposed to differing levels of an anti‐fungal agent during their growth cycle. The satellite uses a 10 cm x 10 cm x 30 cm Cubesat‐class structure with body‐mounted solar panels, an ISM‐band transceiver, and a simple PIC‐class microcontroller for the main flight computer. PharmaSat was launched on May 19, 2009 from Wallops Flight Facility as a secondary payload on a Minotaur launch vehicle. During the first week of operation, the primary biological experiment was conducted, and data from this experiment was downloaded thereby achieving mission success. The PharmaSat design and mission control architecture inherits many features and design strategies from the GeneSat‐1 mission, which was previously developed by the same design group at NASA Ames Research Center and Santa Clara University. This paper presents the PharmaSat mission, the design of its spacecraft and ground segment, and initial flight results.

Alternate  Nanosatellite Tracking Ships: From Concept to Launch in Seven Months

Freddy Pranajaya, Robert Zee – Space Flight Laboratory/University of Toronto; Jeff Cain, Richard Kolacz – COM DEV Limited

ABSTRACT: The Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies and COM DEV Ltd have developed a low Earth orbit nanosatellite in less than seven months to perform rapid turnaround experiments in space to detect and study Automatic Indentification System (AIS) signals transmitted by maritime vessels. The satellite, known as "Nanosatellite Tracking Ships" (NTS) leverages both SFL’s CanX‐2 nanosatellite technology and Generic Nanosatellite Bus (GNB) mechanical design to house a custom AIS receiver payload developed by COM DEV Ltd. NTS was developed under an extremely tight schedule, with on‐orbit results required within a year from contract start. NTS have successfully met all of its mission objectives and continues to operate in orbit. This paper outlines how SFL and COM DEV were able to rapidly design, construct and deploy a custom satellite to respond to the opportunity to bring on‐orbit AIS detection services to the international community. This paper also provides an overview of the on‐orbit data collected thus far outlining the capability of the spacecraft.