A preliminary study of resistance to wilt caused by Fusarium lycopersici Sacc., and earliness in the tomato cross, Bonny Best X Marglobe

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Cover Crops Cover a Lot of Possibilities

Cover crops have been used for centuries. However, today\u27s modern farmers have grown up in a generation or two which has replaced the use of cover crops with fertilizers and herbicides

Red Clover Variety Persistence Trial

In response to questions about the longevity of the forage legume red clover (Trifolium pretense) in northwest Iowa, a variety trial was initiated in 2010 with a few examples of alternative red clover varieties. For a long time, red clover has been considered a shortlived (2-year) perennial, with some yield in the planting year and generally good production for one additional production year. Plants generally are lost because of a combination of root and crown diseases and winterkill. Red clover breeders have been selecting for improved plant resistance to the root/crown vascular wilt diseases, as well as northern and southern anthracnose. With improvement in anthracnose resistance has come somewhat better persistence. Several new red clover varieties are being marketed as 3- and 4-year production varieties

Safe Construction in Space: Using Swarms of Small Satellites for In-Space Manufacturing

With the emergence of a new space-to-space servicing sector, along with the return of manned missions beyond low earth orbit, there is an increased need for quick, efficient, and most of all, safe Rendezvous and Proximity Operations (RPO). An additional next big step forward may be true manufacturing in space, which could take advantage of swarms of small satellites cooperating in close proximity to each other, all subjected to the same laws of orbital mechanics. Currently, there is a lack of knowledge about how to safely operate a swarm of spacecraft in close quarters in a dynamically changing environment (i.e., a “space construction site”), without creating a high risk of collision and/or potential debris creation. In order to formulate a stable, recurring, and efficient set of trajectories, a method was developed using genetic algorithms. This set of algorithms is able to solve for a set of relative motion trajectories for a swarm of N spacecraft, taking into account gravitational perturbations, to obtain trajectories that are recurring over a set amount of time. These algorithms also have the capability to dynamically alter the trajectories in order to take into account changes to the system, such as the addition of new spacecraft, or individual spacecraft failures

Alternative Grass Variety Trial 2010–2012

In response to questions about the suitability of some relatively new or different forage grass species for northern Iowa, a variety trial was initiated in 2010 with a few examples of alternative forage grasses. Among the entries tested were two intermediate wheatgrass varieties and two meadow bromegrass varieties

Low Cost Magnetosphere Measurement: Leveraging Fusion of Low Data Rate Downlink with Amateur Radio Community

In the last 10-20 years, the simplified structure and low-costattributes of CubeSats have given universities and other student groups the opportunity to build and launch their own small satellites. This was the case with the University of Southern California’s 4th CubeSat, Magneto. Magneto’s mission objective is to validate two magnetometers, provided in partnership by Omega Engineering, by attempting to map the Earth’s magnetic field in a low Earth orbit (LEO). This goal presented a multifaceted problem, characterized by the design challenges associated with building a low-cost CubeSat that can collect and downlink data from all over the globe. A balance had to be maintained, operating within onboard storage limitations and keeping power demands low, while still downlinking enough widespread data to make the mission meaningful. Amateur radio operators around the world were proposed to act as the CubeSat’s distributed global ground station network, providing a means by which to receive downlinked data in locations out of range of Southern California. Additionally, a rotating onboard beacon scheme with stored data points further preserved magnetosphere measurements taken out of range of a ground station. Employing these resources and techniques, the Magneto team hopes to produce a map of the magnetosphere comparable to one produced by European Space Agency (ESA) satellites

The Arkisys Port Module: An Orbital Platform for Hosted Payloads in Low-Earth Orbit

Advances in Small Satellite technology combined with the availability of low-cost rideshares to Low-Earth Orbit (LEO) have led to an increasing number of space missions. However, the underlying technology for small payload missions has been relatively constant over the past two decades: CubeSat form factor platforms for free-flying missions in LEO. Arkisys is working to change this, and allow a wider variety of payloads to reach LEO which don\u27t include an immediate free-flying requirement. This platform is called The Port, and is an autonomous long-duration orbital platform for a multitude of uses, including hosting payloads in LEO. Currently, avenues available to test small experimental payloads in LEO are hosted inside other satellites, or in some cases aboard the International Space Station (ISS) at the ISS National Laboratory. While CubeSats are quite ubiquitous and widely available; the downside is that while they appear low cost, they can be costly for a team who has never developed one before. New companies hosting payloads for customers offer a way to get to space for a limited duration, some even offering to bring them back to Earth. The ISS National Laboratory can support a wider variety of payloads than small satellites alone; however, there is a limited capacity on the ISS, and the missions are limited by human factor constraints. For researchers and commercial developers who want to run small-scale experiments on orbit, on the order of 10 - 200 kg, a long-duration robotic platform which can host these payloads, providing power, data, and thermal control over a standardized docking interface presents a unique opportunity to expand their functional test and operations. On a long duration platform payloads can be situated in an orientation that provides a constant view of the Earth, of deep space, or even a radiation-shielded environment. With a large enough number of payloads on board running at a duty cycle, the per-user cost is able to be brought significantly lower than a one-off small satellite mission for an equivalently sized payload. There is a interesting dichotomy in the use of Cubesat/Small Satellites to support payload testing; the value proposition is typically in building a satellite to last for multiple years, yet many payloads are Technology Readiness Level (TRL) raising demonstrations that only need to run for a matter of months. This results in a potential under-utilization of resources of the satellite. A long-duration platform optimized to allow for any level of maturity of a technology or payload that needs testing on orbit is able to amortize the cost of operation over time and numbers of customers, helping to drive cost down with increased utility and functions passed on to the payload consumer. This paper puts forward Arkisys\u27s alternative approach to hosting new technologies and missions into space that does not require a full satellite to be built and launched, and describes in detail the capabilities and benefits of the Arkisys Port platform as a long-duration orbital platforms to serve short- and medium-term missions to LEO. The goal is to offload some of the existing payload and new technology backlog from the existing methods to accelerate innovation in space technology today

Paper Session III-C - Accelerated Low cost Liquid Engine Stage Development for Critical Needs Missions

Based on near term mission needs for liquid engine target stages for the Strategic Defense Initiative Organization (SDIO) Office, the Astronautcs Laboratory at Edwards AFB, California, and the Jet Propulsion Laboratory in Pasadena, California, have formed an unparalleled alliance to develop an accelerated low cost liquid engine target stage program. To satisfy high profile accelerated projects in support of SDIO near and long term missions, liquid target stage development is needed for a variety of mission support roles. The AL and JPL laboratories have brought to life a unique method and philosophy for creating an accelerated program to develop a liquid target stage. The philosphy utilizes inherent advantages present in surplus flight qualified components as the basis for a design start, then accelerating the design process using conservative constraints, fabricating structural components from preliminary released design drawings, and assembling the components from first release assembly drawings. Vehicle assembly is in structure specific stages, thereby allowing all design, fabrication, and assembly disciplines to run in parallel, developing a fast paced flow from ideas to assembled components. Integration is also broken into phases, with the final product assembled from the structure specific stages. By keeping multiple components and stage segments in parallel in each discipline, changes or problems can be accommodated with a minimum of disturbance, and be incorporated in final assembly with no loss of schedule

Cellular Based Aggregated Satellite System: The Design and Architecture of a Three Degree of Freedom Near-Frictionless Testbed for Ground Validation of CubeSat Operations

As small and nano-satellite operations become more complex and increase in functionality, the need to validate new concepts prior to deployment in a low-cost and time efficient manner has further increased. While computer simulations have traditionally provided acceptable results for guidance navigation and control (GNC) algorithms, more complex actions such as rendezvous and proximity operations and docking (RPOD) require alternative methods, which often require ground-based platforms. The concept of on-orbit autonomous docking of small satellites has grown in popularity due to its broad range of applications. However, most existing ground testing platforms (GTP) are expensive due to the technologies used and large physical space required. Due to the importance of RPOD to nano-satellites specifically, the development of a low-profile GTP is a crucial component in the testing and validation of small satellite concepts. The Space Engineering Research Center (SERC) at the University of Southern California (USC) has designed and manufactured a GTP capable of validating various unique nano-satellite operations in a cost-effective and space-efficient manner. This paper will focus on the design and architecture of a three degree of freedom (3DoF) near-frictionless testbed for ground validation of RPOD in a microgravity environment and its use with various small satellite applications

Evaluating the adaptability of forage species and varieties

Iowa\u27s harsh climate can make forage establishment and maintenance difficult. This project examined which forages might be best adapted to growth and survival in northwest Iowa