How Not to Build a CubeSat – Lessons Learned from Developing and Launching NMSU\u27s First CubeSat

Ionospheric Neutron Content Analyzer (INCA), a student led CubeSat project at New Mexico State University (NMSU). INCA is launching on NASA’s ELaNa 20 mission carrying a neutron detector designed and built by NASA’s Goddard Space Flight Center. The INCA mission is the first spacecraft built by New Mexico State University in many years, as such, the program was essentially started from scratch with minimal pre-existing resources. While eventually successful, INCA took many missteps along the way, starting out as a 6U, eventually being completely redesigned to a 3U, before launching after around six years of development. This paper documents INCA’s design, build, and early operations, along the way the team learned many lessons about designing and building a small satellite in the context of a university program. This paper is targeted at new university teams considering starting a mission, documenting best practices learned by the INCA team, and some pitfalls to avoid

Virtual Telescope for X-Ray Observations

Selected by NASA for an Astrophysics Science SmallSat study, The Virtual Telescope for X-Ray Observations (VTXO) is a small satellite mission being developed by NASA’s Goddard Space Flight Center (GSFC) and New Mexico State University (NMSU). VTXO will perform X-ray observations with an angular resolution around 50 milliarcseconds, an order of magnitude better than is achievable by current state of the art X-ray telescopes. VTXO’s fine angular resolution enables measuring the environments closer to the central engines in compact X-ray sources. This resolution will be achieved by the use of Phased Fresnel Lenses (PFLs) optics which provide near diffraction-limited imaging in the X-ray band. However, PFLs require long focal lengths in order to realize their imaging performance, for VTXO this dictates that the telescope’s optics and the camera will have a separation of 1 km. As it is not realistic to build a structure this large in space, the solution being adapted for VTXO is to place the camera, and the optics on two separate spacecraft and fly them in formation with the necessary spacing. This requires centimeter level control, and sub-millimeter level knowledge of the two spacecraft’s relative transverse position. This paper will present VTXO’s current baseline, with particular emphasis on the mission’s flight dynamics design

Trajectory Optimization for the Virtual Telescope for X-Ray Observations

The Virtual Telescope for X-Ray Observations (VTXO) is a long focal length telescope which promises to provide orders of magnitude improvement in angular resolution in the X-ray band. VTXO will include a Phased Fresnel Lens (PFL), which provides nearly diffraction-limited imaging, with a 1 km focal length. The PFL is carried by the Optics Spacecraft, which flies in a formation with the Detector Spacecraft, approximating a rigid telescope body. In order to maintain the formation requirements, while pointing the telescope axis at the desired astronomical targets, one spacecraft will be traveling on a non-natural trajectory, requiring the vehicle to maneuver regularly to maintain the telescope pointing. If care is not taken in the trajectory design, these paths result in large propellant consumption. However, there is an opportunity to optimize trajectories when re-arranging the formation between different astronomical targets. This paper presents an optimization scheme for re-pointing the telescope, utilizing a non-traditional path-based cost function to solve the propellant optimal trajectory. The resulting trajectories show a factor of four improvement in propellant consumption compared to the baseline. The optimization techniques developed for VTXO are applicable to orbits ranging from low-Earth orbit, to highly eccentric Earth orbits, and Lagrange point orbits

Navigation and Control Performance Utilizing Precision Formation Flying Along a Propellent Optimized Trajectory for the VTXO Mission

The Virtual Telescope for X-Ray Observations (VTXO) is part of a new generation of distributed component, long focal length telescopes which promise to provide orders of magnitude improvement in angular resolution in the X-ray band over the current state of the art. VTXO will include Phased Fresnel Lenses (PFL), which provide nearly diffraction-limited imaging, with around a 1 km focal length carried by the Optics Spacecraft (OSC), which will fly in a precision formation with the Detector Spacecraft (DSC) approximating a rigid telescope body, with the telescope achieving nearly 50 milli-arcsecond angular resolution in the 4.5 – 6.7 keV X-ray band [1]. In order to maintain the precise formation requirements, while pointing the telescope axis at the desired astronomical targets, one or both spacecraft will inherently be traveling on a non-natural orbit trajectory. These families of trajectories require one or both vehicles to maneuver regularly to maintain the desired path

Development of a new SonovueTM contrast-enhanced ultrasound approach reveals temporal and age-related features of muscle microvascular responses to feeding

Compromised limb blood flow in aging may contribute to the development of sarcopenia, frailty, and the metabolic syndrome. We developed a novel contrast-enhanced ultrasound technique using Sonovue™ to characterize muscle microvasculature responses to an oral feeding stimulus (15 g essential amino acids) in young (~20 years) and older (~70 years) men. Intensity-time replenishment curves were made via an ultrasound probe “fixed” over the quadriceps, with intermittent high mechanical index destruction of microbubbles within muscle vasculature. This permitted real-time measures of microvascular blood volume (MBV), microvascular flow velocity (MFV) and their product, microvascular blood flow (MBF). Leg blood flow (LBF) was measured by Doppler and insulin by enzyme-linked immunosorbent assay. Steady-state contrast concentrations needed for comparison between different physiological states were achieved <150 sec from commencing Sonovue™ infusion, and MFV and MBV measurements were completed <120 sec thereafter. Interindividual coefficients of variation in MBV and MFV were 35–40%, (N = 36). Younger men (N = 6) exhibited biphasic vascular responses to feeding with early increases in MBV (+36%, P < 0.008 45 min post feed) reflecting capillary recruitment, and late increases in MFV (+77%, P < 0.008) and MBF (+130%, P < 0.007 195 min post feed) reflecting more proximal vessel dilatation. Early MBV responses were synchronized with peak insulin but not increased LBF, while later changes in MFV and MBF occurred with insulin at post absorptive values but alongside increased LBF. All circulatory responses were absent in old men (N = 7). Thus, impaired postprandial circulation could impact age-related declines in muscle glucose disposal, protein anabolism, and muscle mass

A Europa CubeSat Concept Study for Measuring Europa\u27s Atmosphere

This presentation is the product of a nine-month mission concept study for a CubeSat that would be carried aboard the JPL Europa Multiple-Flyby Mission, released in the Jovian system and make measurements at Europa. We examined the scientific return as well as the technical feasibility of a CubeSat designed to study the linkage between Europa\u27s radiation environment which generates Europa\u27s atmosphere through sputtering and radiolytic processes, and its atmospheric structure. This would be accomplished by measuring a) energetic particles at Europa and b) its atmospheric density through drag forces on the CubeSat. The findings of our concept study for the Deployable Atmospheric Reconnaissance CubeSat with Sputtering Ion Detector at Europa (DARCSIDE) indicate that the technology exists to enable a 3U, 4.4 kg CubeSat to detect Europa\u27s tenuous atmosphere beginning ~200 km above the surface for ~400 s of flight time during a single flyby, by measuring drag on the vehicle. By including a charged particle detector, we can also measure the sputtering-induced charged particle flux incident on Europa\u27s surface - either for a single arc across the surface or for a number of predeployment Jovian orbits while onboard the Europa Multiple-Flyby Mission - depending on the length of time the instrument is powered on. In addition to providing highly complementary science to the Europa Multiple-Flyby Mission, the combination of the accelerometer and charged particle detector will yield important insights for the study of Europa\u27s atmosphere and surface composition, its interaction with the Jovian magnetosphere, and possibly links to its subsurface ocean. This presentation will be focused on the technical challenges of the DARCSIDE mission. The major challenges to be discussed will include how to survive with only one twenty-fifth the energy available at the Earth, this has significant implications for spacecraft temperature and electrical power generation. Additionally, survival in the extreme Jovian radiation environment will be discussed, along how to meet planetary protection requirements for Europa, which requires DARCSIDE to never impact Europa. Finally, the design for the DARCSIDE drag system, and accelerometers will be discussed

VTXO: The Virtual Telescope for X-ray Observations

The Virtual Telescope for X-ray Observations (VTXO) will use lightweight Phase Frensel Lenses (PFLs) in a virtual X-ray telescope with 1 km focal length and with nearly 50 milli-arc second angular resolution. Laboratory characterization of PFLs have demonstrated near diffraction-limited angular resolution in the X-ray band, but they require long focal lengths to achieve this quality of imaging. VTXO is formed by using precision formation flying of two SmallSats: a smaller, 6U OpticsSat that houses the PFLs and navigation beacons while a larger, ESPA-class DetectorSat contains an X-ray camera, a charged-particle radiation monitor, a precision star tracker, and the propulsion for the formation flying. The baseline flight dynamics uses a highly-elliptical supersynchronous geostationary transfer orbit to allow the inertial formation to form and hold around the 90,000 km apogee for 10 hours of the 32.5-hour orbit with nearly a year mission lifetime. The guidance, navigation, and control (GN&C) for the formation flying uses standard CubeSat avionics packages, a precision star tracker, imaging beacons on the OpticsSat, and a radio ranging system that also serves as an inter-satellite communication link. VTXO’s fine angular resolution enables measuring the environments nearly an order of magnitude closer to the central engines of bright compact X-ray sources compared to the current state of the art. This X-ray imaging capability allows for the study of the effects of dust scattering nearer to the central objects such as Cyg X-3 and GX 5-1, for the search for jet structure nearer to the compact object in X-ray novae such as Cyg X-1and GRS 1915+105, and for the search for structure in the termination shock of in the Crab pulsar wind nebula. In this paper, the VTXO science performance, SmallSat and instrument designs, and mission description is described. The VTXO development was supported as one of the selected 2018 NASA Astrophysics SmallSat Study (AS3) missions