Michael Swartwout

A brief history of rideshares (and attack of the CubeSats)

Rideshares (“piggyback” launches) go almost back to the first satellite launches, with the first one in 1960. Given the extraordinary cost of launch, it is natural to seek out ways to share costs, or to make use of the unused capacity of a larger launch vehicle. One tool that would be of use to mission planners is a statistical look at past rideshares to help understand the opportunities and obstacles for prospective future rideshares. The purpose of this paper is to begin to collect the data necessary for such analyses, and to start identifying the fundamental issues. 12

A statistical survey of rideshares (and attack of the CubeSats, part deux)

In last years conference, we presented a statistical look at the 316 rideshare missions launched from 1990-2010, examining issues of mass, nations of origin and launch and mission type. Examinations of the data indicated that the broad range of mission types, sizes and participating nations could be classified in several useful ways. For example, we were able to forecast a bifurcation of rideshares into the CubeSat-scale and ESPA-scale categories. In this paper, we will expand on last years results in three meaningful ways. First, we will extend the analysis back to the first rideshare in 1960 and up through 2011. In doing so, we will be able to confirm what were anecdotal conjectures from the previous paper: that the changes in the numbers and demographics of rideshares can be tied to the availability of specific launch vehicles/systems (namely the Ariane, Dnepr, Shuttle and P-POD); and that the avalanche of CubeSat flights represents a significant change in the nature of rideshares. The second extension of previous work will be the further subclassification of rideshares into military, civil, commercial and educational categories. Identifying the nature of the rideshare operator will help us better correlate the launches available to different missions. For example, we will show that the large number of U.S. rideshare missions is actually a large number of DoD rideshare missions, with a handful of U.S. civil, commercial and educational flights (most of them in the last 5 years). With this new data, we will further refine our forecasts of the launches available for various mission categories in the next few years.

Cheaper by the dozen: The avalanche of rideshares in the 21st century

In the previous two conferences, we presented a statistics-based history of rideshares, first with the 300 rideshares launched from 1990-2010, then with the 600 rideshares launched in the first 54 years of spaceflight. We showed that there have been several waves of rideshares, each with their own particular characteristics: the avalanche of US military rideshares of the 60s (acting as calibration targets, environmental sensors and performing other space-qualification tasks); the slow-build of commercial rideshares starting with the Ariane ASAP in the early 80s, and now a bifurcation into 100-kg ESPA-class spacecraft and a second, larger avalanche of CubeSats.

Secondary spacecraft in 2016: Why some succeed (And too many do not)

This paper updates previous reviews of secondary spacecraft. With the number of new secondary spacecraft exceeding 100 per year, it is necessary to revisit the data, to better understand the trends and make new predictions. While CubeSats are the dominant type of secondary payloads, they are not the sole focus of this work. For 2016, we will re-examine our data and previous claims using a new set of classifications. We now believe that secondary-spacecraft developers are best divided into three groups: novices, traditionalists and experimentalists. Each of these groups approaches the development and operation of rideshares in very different ways, and the mission success rates between the three groups diverge. In this paper, we will review the census data (mass, lifetime, mission category, contributing organizations), examining trends and identifying deviations from (or confirmations of) previous predictions. Our focus will be on mission success and failure. We have accumulated sufficient information to define failure rates based on the type of organization, and to identify most-likely-causes based on the mission and organization type.

Argus: A flight campaign for modeling the effects of space radiation on modern electronics

The effects of radiation on modern electronics are not well understood; devices with length scales below 60 nm are sensitive across a wider range of input energies and respond differently to different species than larger devices. This is not a trivial issue: existing predictive failure models are off by as much as three orders of magnitude. Complicating the problem is that modern devices have dozens of operating modes, requiring orders of magnitude more testing time. This increase in the required time (and cost) for ground testing, coupled with the greatly reduced cost (and development time) for space experimentation via CubeSats, has made spaceflight a sensible complement to ground testing. The Institute for Space and Defense Electronics (ISDE) at Vanderbilt University has partnered with the Space Systems Research Laboratory at Saint Louis University to develop Argus, a proposed flight campaign of perhaps a dozen CubeSat-class spacecraft spanning years. Argus will fly an array of radiation-effects modeling experiments; on-orbit event rates will be compared against ground predictions to help calibrate new predictive models developed at ISDE. Argus leverages COTS CubeSat systems and the extremely simple payload requirements to field a set of very low-cost, very automated passive platforms developed by students at both institutions. This paper will describe the challenges in modeling radiation effects on modern electronics as well as the new models developed at ISDE. The Argus campaign concept and drivers will be discussed, and the first two missions will be presented: COPPER, which flies in late 2012, and Argus-High, proposed for a 2013 launch.

The Argus mission: Detecting thruster plumes for Space Situational Awareness

The growing capability for proximity-operations missions requires a new capability in Space Situational Awareness (SSA): detecting the presence of other spacecraft operating within 2–5 km of a high-value asset. While significant effort is being devoted to visible-wavelength observation using ground-based systems, we believe that multi-spectral imaging (e.g., long-wavelength infrared, visible and ultraviolet) and particle impact detectors (e.g., mass spectrometers) could be used for in-situ detection of the thruster plumes of spacecraft entering an observational orbit around the high-value asset as well as maintaining it.12

Feasibility of a deployable boom aboard picosatellites for instrumentation and control purposes

Until the 1990s, satellites grew ever larger in both size and mass. NASA administrator, Daniel Goldin, urged for a “faster, better, cheaper” approach that created a wide variety of programs including microsatellite research. Picosatellites, weighing less than 1 kilogram, are one branch of these miniature spacecraft. Their reduced size allows them to be launched in mass quantities at low cost and provides many opportunities not always permitted by larger structures. Unfortunately, while small spacecraft technology has proved to reduce cost and development time, their small size limits the possibilities of certain design concepts. One way to widen the capabilities of these small satellite systems is by utilizing a deployable boom. The boom is stowed within a picosatellite prior to launch and extends into a deployed state once in low Earth orbit. Once in space, the boom serves a two-fold purpose. First, it can be used as a passive form of control to help stabilize and orient the satellite using a reliable gravity-gradient technique. Secondly, on-board instruments could be placed at the tip of the extended boom to minimize any magnetic and electronic interference with internal bus components. Extendable booms have proven space flight heritage on larger microsatellites like QuakeSat and PRISM. Initial research, however, suggests that this concept has not been adapted to the smaller class of picosatellites. This study takes a deeper look into the history of deployable structures on microsatellites in the hope of designing a boom capable of operating within a picosatellite. Various trade off studies are performed, placing heavy emphasis on choosing a suitable boom type and deployment technique while taking into consideration well defined mass, volume, and power constraints. After choosing an appropriate boom and deployment method, a computer-aided design (CAD) model will outline the final boom design both in its stored and deployed configurations. The structural integrity and physical limitations of the boom are demonstrated by performing a finite element dynamic analysis that simulates typical launch loads. Finally, a MATLAB code is utilized to simulate and verify the stability and effectiveness of the chosen gravity-gradient boom design. Introducing a deployable boom in a picosatellite allows for a reliable, inexpensive form of control while simultaneously allowing for more accurate instrumentation data by reducing system noise. By keeping cost and development time low, an extendable boom can expand the current capability of picosatellites to a wider aerospace population, including the university level.