Giovanni Minelli

The O/OREOS Mission: First Science Data from the Space Environment Survivability of Living Organisms (SESLO) Payload

We report the first telemetered spaceflight science results from the orbiting Space Environment Survivability of Living Organisms (SESLO) experiment, executed by one of the two 10 cm cube-format payloads aboard the 5.5 kg Organism/Organic Exposure to Orbital Stresses (O/OREOS) free-flying nanosatellite. The O/OREOS spacecraft was launched successfully to a 72° inclination, 650 km Earth orbit on 19 November 2010. This satellite provides access to the radiation environment of space in relatively weak regions of Earths protective magnetosphere as it passes close to the north and south magnetic poles; the total dose rate is about 15 times that in the orbit of the International Space Station. The SESLO experiment measures the long-term survival, germination, and growth responses, including metabolic activity, of Bacillus subtilis spores exposed to the microgravity, ionizing radiation, and heavy-ion bombardment of its high-inclination orbit. Six microwells containing wild-type (168) and six more containing radiation-sensitive mutant (WN1087) strains of dried B. subtilis spores were rehydrated with nutrient medium after 14 days in space to allow the spores to germinate and grow. Similarly, the same distribution of organisms in a different set of microwells was rehydrated with nutrient medium after 97 days in space. The nutrient medium included the redox dye Alamar blue, which changes color in response to cellular metabolic activity. Three-color transmitted intensity measurements of all microwells were telemetered to Earth within days of each of the 48 h growth experiments. We report here on the evaluation and interpretation of these spaceflight data in comparison to delayed-synchronous laboratory ground control experiments.

The O/OREOS Mission: First Science Data from the Space Environment Viability of Organics (SEVO) Payload

We report the first science results from the Space Environment Viability of Organics (SEVO) payload aboard the Organism/Organic Exposure to Orbital Stresses (O/OREOS) free-flying nanosatellite, which completed its nominal spaceflight mission in May 2011 but continues to acquire data biweekly. The SEVO payload integrates a compact UV-visible-NIR spectrometer, utilizing the Sun as its light source, with a 24-cell sample carousel that houses four classes of vacuum-deposited organic thin films: polycyclic aromatic hydrocarbon (PAH), amino acid, metalloporphyrin, and quinone. The organic films are enclosed in hermetically sealed sample cells that contain one of four astrobiologically relevant microenvironments. Results are reported in this paper for the first 309 days of the mission, during which the samples were exposed for ∼2210 h to direct solar illumination (∼1080 kJ/cm(2) of solar energy over the 124-2600 nm range). Transmission spectra (200-1000 nm) were recorded for each film, at first daily and subsequently every 15 days, along with a solar spectrum and the dark response of the detector array. Results presented here include eight preflight and 16 in-flight spectra of eight SEVO sample cells. Spectra from the PAH thin film in a water-vapor-containing microenvironment indicate measurable change due to solar irradiation in orbit, while three other nominally water-free microenvironments show no appreciable change. The quinone anthrarufin showed high photostability and no significant spectroscopically measurable change in any of the four microenvironments during the same period. The SEVO experiment provides the first in situ real-time analysis of the photostability of organic compounds and biomarkers in orbit.

SEVO ON THE GROUND: DESIGN OF A LABORATORY SOLAR SIMULATION IN SUPPORT OF THE O/OREOS MISSION

This technical note describes a novel solar simulation experiment designed to mimic the solar radiation experienced by the Organism/Organics Exposure to Orbital Stresses (O/OREOS) nanosatellite in low-Earth orbit. Thin films of organic compounds within hermetically sealed sample cells (identical to the films and cells of the spaceflight mission) were exposed to simulated AM0 solar radiation in the laboratory for a total of 6 months, and monitored for spectral changes at two-week intervals. The laboratory experiment accurately simulated ultraviolet and visible solar irradiance to within 2% from 200‐1000 nm and the Ly! (121.6 nm) emission line radiation to within 8%. Design and calibration parameters for the experiment are discussed in detail for this ground-based laboratory irradiation experiment, which was built as a complement to, and as scientific validation of, the O/OREOS SEVO experiment in space.

Responsive Small Satellite Mission Operations Using An Enterprise-Class Internet-Based Command and Control Network

Rapid integration of spacecraft into low-cost mission control systems is an essential element of enabling cost-effective, responsive space missions. This paper describes a distributed satellite ground segment and control network that is developed and operated by students at Santa Clara University in order to support a wide variety of NASA and university-class small spacecraft. In addition to reviewing the technical design of the system and summarizing the missions being supported, the paper outlines several strategies for implementing a low-cost system that supports rapid integration of new spacecraft.