Flight Opportunities Program Research Articles

APL JANUS System Progress on Commercial Suborbital Launch Vehicles: Moving the Laboratory Environment to Near Space

Abstract Multiple private companies are building suborbital reusable launch vehicles possessing vastly different designs. Many of these companies originally focused on space tourism; however, revolutionary applications for scientific and engineering research as well as technology demonstrations and instrument development are emerging. The dramatic reduction in cost over traditional launch systems as well as a guaranteed (and rapid) safe payload return enable many new launch vehicle applications. These new capabilities will essentially move the laboratory environment up to the edge of space. To make use of these novel launch vehicles, the John Hopkins University Applied Physics Laboratory has established a Commercial Suborbital Program with a core system (JANUS) to support and enable many future suborbital missions. This program has already conducted six suborbital flight missions to establish vehicle interfaces and analyze the suitability and limits of each flight environment. Additionally, this program has also been selected by the NASA Flight Opportunities Program for five additional operational suborbital missions. Here we present the results of our completed missions as well as descriptions of future selected missions scheduled for 2021–2023.

Customized Real-Time Interior-Point Methods for Onboard Powered-Descent Guidance

This paper presents a new onboard-implementable, real-time convex optimization-based powered-descent guidance algorithm for planetary pinpoint landing. Earlier work provided the theoretical basis of convexification, the equivalent representation of the fuel-optimal pinpoint landing trajectory optimization problem with nonconvex control constraints as a convex optimization problem. Once the trajectory optimization problem is convexified, interior-point method algorithms can be used to solve the problem to global optimality. Though having this guarantee of convergence motivated earlier convexification results, there were no real-time interior point method algorithms available for the computation of optimal trajectories on flight computers. This paper presents the first such algorithm developed for onboard use and flight-tested on a terrestrial rocket with the NASA Jet Propulsion Laboratory and the NASA Flight Opportunities Program in 2013. First, earlier convexification results are summarized and the resulting second-order cone-programming problem for fuel-optimal trajectory optimization is presented. Then, the proposed, fairly generic, second-order cone-programming interior point method algorithm is presented in detail with an overview of the customization process for real-time computations. Customization exploits a specific problem structure to increase the computational speed, which is shown to decrease run times by two to three orders of magnitude in many applications. A new convexification result for maximal-divert trajectories with active velocity constraints is also presented herein.

Development of a Microgravity Research Team Project Course

A “hands-on” Microgravity Research Team two-semester engineering research project course sequence has been developed and offered at West Virginia University over the past 15 years. The primary course goal is to provide students with a hardware-oriented, hands-on, open-ended experimental research project experience. During the first semester, the teams of four to 12 undergraduate students develop an experimental concept and hypothesis to be studied in microgravity conditions and then submit a detailed technical proposal for their experiment for review by the NASA Reduced Gravity Student Flight Opportunities Program, or more recently to the Reduced Gravity Education Flight Program. Twelve successful experiments have been selected and flown aboard microgravity research aircraft in the past 15 years, with the 2014–2015 team working to develop an experiment to propose for any parabolic trajectory student program that may become available in the near future. Because of cancellation of the program during the 2014–2015 year, over the past year the course has been significantly modified to use a new 1.25 s West Virginia University drop tower and a general aviation aircraft, to obtain low-gravity experimental data, to continue the program. These program modifications are briefly described, and a return of the program is advocated.

High-Flying Success for Chemistry Students: NASA's Reduced Gravity Student Flight Opportunities Program

High-Flying Success for Chemistry Students: NASA's Reduced Gravity Student Flight Opportunities Program

The role of gravity in the motion of plasma arcs inside ‘Plasma Balls’: An investigation in the NASA reduced gravity student flight opportunities program

We present results of an investigation performed by undergraduates as part of the NASA Reduced Gravity Student Flight Opportunities Program. The goal was to determine the importance of buoyancy-driven convection on the motion of plasma streamers in commercially available ‘plasma balls.’ The motion of the plasma streamers was studied as a function of acceleration level provided by drop experiments and parabolic flights on NASA’s KC-135. We determined that there were more than two contributing factors to the motion of plasma arcs: buoyancy-driven convection and magnetic fields from the Tesla coil that generated the high voltage in the plasma ball. When the plasma ball was isolated from the Tesla coil, the streamer velocities were higher. The velocities were nonzero at zero acceleration level and increased with increasing acceleration level. The nonzero velocity at zero acceleration could be the result of residual acceleration in the KC-135 or more likely an intrinsic aspect of this system.

Zero-g acoustic fire suppression system

The objective is to study the effects of acoustics on a flame in microgravity. This research is meant to provide a new approach to reducing and extinguishing a combustion reaction in space (where a conventional fire extinguisher is hazardous). The group proposes to test the following hypotheses: (1) as sound intensity increases, so does the magnitude of the effect on the flame; (2) there is one optimal frequency for maximizing the effects of sound waves on a flame; (3) homogeneous flames (found only in microgravity) can be affected in a single area separate from others; (4) a sustained pulse of sound, rather than a single, brief pulse, can be used to extinguish a flame. The group will describe the experimental apparatus in detail, which was flown aboard a NASA C-9B Aircraft through their Reduced Gravity Student Flight Opportunities Program (RGSFOP), and present the findings and compare data obtained in a 1-g environment with data collected in a microgravity environment. [Thanks to the following organizations for their support: Kicker Audio, Georgia Space Grant Consortium, Siemens, FLIR Systems, PCB Piezotronics, UWG Honors College, and NASAs Reduced Gravity Student Flight Opportunities Program.]