Engineering topics

Wercinski, Paul F.

Publications and source records attributed to Wercinski, Paul F..

At least 19 records

NASA NTRS2019

ADEPT Sounding Rocket One Flight Test Overview

On September 12th, 2018, a sounding rocket flight test was conducted on a mechanically-deployed atmospheric entry system known as the Adaptable Deployable Entry and Placement Technology (ADEPT). The purpose of the Sounding Rocket One (SR-1) test was to gather critical flight data for evaluating the vehicle's in-space deployment performance and supersonic stability. This flight test was a major milestone in a technology development campaign for Nano-ADEPT: the application of ADEPT for small secondary payloads. The test was conducted above White Sands Missile Range, New Mexico on a SpaceLoft XL rocket manufactured by UP Aerospace. This paper describes the system components, hardware development campaign, test execution, and test conclusions.

Cassell, Alan M.↗

NASA NTRS2018

Adaptive Deployable Entry Placement Technology (ADEPT) Development for Small Sat Class Venus Missions

The Adaptable, Deployable Entry and Placement Technology (ADEPT) is a novel approach for entry vehicle design. Similar to an umbrella, it is stowed during launch and deployed prior to entry. ADEPT employs a high performance, 3-D woven, carbon fabric to serve as the primary surface of the mechanically deployed system. The successful ADEPT sounding rocket flight test matured the 1-meter Class ADEPT in the areas of deployment and structural integrity, and provided aerodynamic flight characteristics of the ADEPT open-back configuration from Mach 3 to Mach 0.3. Aerocapture uses the aerodynamic drag from a single hyperbolic atmospheric pass to provide the delta-V needed for orbit insertion. Studies suggest that, compared to propulsive orbit insertion, aerocapture could increase delivered payload by 70 percent at Venus. Drag modulation aerocapture, which shows promise of being simpler and more cost-effective than the more-often studied lift modulation methods, uses in-flight transformations of an entry vehicle's drag area to control the amount of deceleration produced during an atmospheric pass. In single-event drag modulation, a drag device is jettisoned after the appropriate deceleration. ADEPT, due to its unique ability to fold and unfold, is being considered for this SmallSat class payload mission applications.

Cassell, Alan M.↗

NASA NTRS2017

NASA's Advanced TPS Materials and Technology Development: Multi-Functional Materials and Systems for Space Exploration

NASA's future missions will be more demanding. They require materials to be mass efficient, robust, multi-functional, scalable and able to be integrated with other subsystems to enable innovative missions to accomplish future science missions. Thermal protection systems and materials (TPSM) are critical for the robotic and human exploration of the solar system when it involves entry. TPSM is a single string system with no back-up. Mass efficiency and robustness are required. Integration of TPSM with the aeroshell is both a challenge and an opportunity. Since 2010, NASA's Space Technology Mission Directorate has invested in innovative new materials and systems across a spectrum of game changing technologies. In this keynote address, we plan to highlight and present our successful approaches utilized in developing four different materials and system technologies that use innovative new manufacturing techniques to meet mission needs. 3-D weaving and felt manufacturing allowed us to successfully propose new ways of addressing TPSM challenges. In the 3-D MAT project, we developed and delivered a multi-functional TPS materials solution, in under three years that is an enabler for Lunar Capable Orion Spacecraft. Under the HEEET project, we are developing a robust heat-shield that can withstand extreme entry conditions, both thermally and mechanically, for entry at Venus, Saturn or higher speed sample return missions. The improved efficiency of HEEET allows science missions entry at much reduced G'loads enabling delicate science instruments to be used. The ADEPT concept is a foldable and deployable entry system and the critical component is a multi-functional fabric that is foldable and deployable and also functions as a mechanical aeroshell and a TPS. The fourth technology we will highlight involves felt to address integration challenges of rigid ablative system such as PICA that was used on MSL. The felt technology allows us to develop a compliant TPS for easy integration. The above four technology developments have focused on mission infusion as the success criteria. These technologies are in different stages of mission infusion. These innovations have led to new mission concepts to be proposed in the future. In our keynote address we will present approaches we have employed throughout the project to create the bridge to transition from low TRL to mission infusion and to overcome the traditional TRL valley of death.

TPS↗

NASA NTRS2017

ADEPT SR-1 Flight Experiment

The ADEPT architecture represents a completely new approach for entry vehicle design using a high-performance carbon fabric to serve as the primary drag surface of the mechanically deployed decelerator and to protect the payload from hypersonic aerothermal heating during entry. The initial system-level development of the nano-ADEPT architecture will culminate in the launch of a 0.7-m deployed diameter ADEPT sounding rocket flight experiment. The SR-1 sounding rocket flight experiment is a critical milestone in the technology maturation plan for ADEPT and will generate performance data on in-space deployment and aerodynamic stability.

aeroshell↗

NASA NTRS2015

Adaptable Deployable Entry and Placement Technology (ADEPT)

No abstract available

Deployable↗

NASA NTRS2013

Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions:An Overview of the Technology Maturation Effort

The Office of Chief Technologist, NASA identified the need for research and technology development in part from NASAs Strategic Goal 3.3 of the NASA Strategic Plan to develop and demonstrate the critical technologies that will make NASAs exploration, science, and discovery missions more affordable and more capable. Furthermore, the Game Changing Development Program is a primary avenue to achieve the Agencys 2011 strategic goal to Create the innovative new space technologies for our exploration, science, and economic future. The National Research Council (NRC) Space Technology Roadmaps and Priorities report highlights six challenges and they are: Mass to Surface, Surface Access, Precision Landing, Surface Hazard Detection and Avoidance, Safety and Mission Assurance, and Affordability. In order for NASA to meet these challenges, the report recommends immediate focus on Rigid and Flexible Thermal Protection Systems. Rigid TPS systems such as Avcoat or SLA are honeycomb based and PICA is in the form of tiles. The honeycomb systems are manufactured using techniques that require filling of each (38 cell) by hand, and in a limited amount of time all of the cells must be filled and the heatshield must be cured. The tile systems such as PICA pose a different challenge as the low strain-to-failure and manufacturing size limitations require large number of small tiles with gap-fillers between the tiles. Recent investments in flexible ablative systems have given rise to the potential for conformal ablative TPS. A conformal TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials. The high strain-to-failure nature of the conformal ablative materials will allow integration of the TPS with the underlying aeroshell structure much easier and enable monolithic-like configuration and larger segments (or parts) to be used. By reducing the overall part count, the cost of installation (based on cost comparisons between blanket and tile materials on shuttle) should be significantly reduced. The conformal ablator design will include a simplified design of seams between gore panels, which should eliminate the need for gap filler design, and should accommodate a wider range of allowable carrier structure imperfections when compared to a rigid material such as PICA.The Conformal TPS development project leverages the past investments made by earlier projects with a goal to develop and deliver a TRL 5 conformal TPS capable of 250 Wcm2 for missions such as MSL or COTS missions. The capabilities goal for the conformal TPS is similar to an MSL design reference mission (250 Wcm2) with matching pressures and shear environments. Both conformal and flexible carbon-felt based materials were successfully tested in stagnation aerothermal environments above 500 Wcm2 under earlier programs. Results on a myriad of materials developed during FY11 were used to determine which materials to start with in FY12. In FY12, the conformal TPS element focused on establishing materials requirements based on MSL-type and COTS Low Earth orbit (LEO) conditions (q 250 Wcm2) to develop and deliver a Conformal Ablative TPS. In FY13, development and refining metrics for mission utilization of conformal ablator technology along with assessment for potential mission stakeholders will be carried out.

Thermal protection materials↗

NASA NTRS2012

Enabling Venus In-Situ Science - Deployable Entry System Technology, Adaptive Deployable Entry and Placement Technology (ADEPT): A Technology Development Project funded by Game Changing Development Program of the Space Technology Program

Venus is one of the important planetary destinations for scientific exploration, but: The combination of extreme entry environment coupled with extreme surface conditions have made mission planning and proposal efforts very challenging. We present an alternate, game-changing approach (ADEPT) where a novel entry system architecture enables more benign entry conditions and this allows for greater flexibility and lower risk in mission design

Wercinski, Paul F.↗

NASA NTRS2012

Mechanically-Deployed Hypersonic Decelerator and Conformal Ablator Technologies for Mars Missions

The concept of a mechanically deployable hypersonic decelerator, developed initially for high mass (~40 MT) human Mars missions, is currently funded by OCT for technology maturation. The ADEPT (Adaptive, Deployable Entry and Placement Technology) project has broad, game-changing applicability to in situ science missions to Venus, Mars, and the Outer Planets. Combined with maturation of conformal ablator technology (another current OCT investment), the two technologies provide unique low mass mission enabling capabilities otherwise not achievable by current rigid aeroshell or by inflatables. If this abstract is accepted, we will present results that illustrate the mission enabling capabilities of the mechanically deployable architecture for: (1) robotic Mars (Discovery or New Frontiers class) in the near term; (2) alternate approaches to landing MSL-class payloads, without the need for supersonic parachute or lifting entry, in the mid-term; and (3) Heavy mass and human missions to Mars in the long term.

Venkatapathy, Ethiraj↗

NASA NTRS2012

Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions: Overview of the Technology Maturation Efforts Funded by NASA's Game Changing Development Program

The Office of Chief Technologist (OCT), NASA has identified the need for research and technology development in part from NASA's Strategic Goal 3.3 of the NASA Strategic Plan to develop and demonstrate the critical technologies that will make NASA's exploration, science, and discovery missions more affordable and more capable. Furthermore, the Game Changing Development Program (GCDP) is a primary avenue to achieve the Agency's 2011 strategic goal to "Create the innovative new space technologies for our exploration, science, and economic future." In addition, recently released "NASA space Technology Roadmaps and Priorities," by the National Research Council (NRC) of the National Academy of Sciences stresses the need for NASA to invest in the very near term in specific EDL technologies. The report points out the following challenges (Page 2-38 of the pre-publication copy released on February 1, 2012): Mass to Surface: Develop the ability to deliver more payload to the destination. NASA's future missions will require ever-greater mass delivery capability in order to place scientifically significant instrument packages on distant bodies of interest, to facilitate sample returns from bodies of interest, and to enable human exploration of planets such as Mars. As the maximum mass that can be delivered to an entry interface is fixed for a given launch system and trajectory design, the mass delivered to the surface will require reduction in spacecraft structural mass; more efficient, lighter thermal protection systems; more efficient lighter propulsion systems; and lighter, more efficient deceleration systems. Surface Access: Increase the ability to land at a variety of planetary locales and at a variety of times. Access to specific sites can be achieved via landing at a specific location (s) or transit from a single designated landing location, but it is currently infeasible to transit long distances and through extremely rugged terrain, requiring landing close to the site of interest. The entry environment is not always guaranteed with a direct entry, and improving the entry system's robustness to a variety of environmental conditions could aid in reaching more varied landing sites."

Beck, Robin A.↗

NASA NTRS2005

Shuttle Orbiter Contingency Abort Aerodynamics: Real-Gas Effects and High Angles of Attack

An important element of the Space Shuttle Orbiter safety improvement plan is the improved understanding of its aerodynamic performance so as to minimize the "black zones" in the contingency abort trajectories [1]. These zones are regions in the launch trajectory where it is predicted that, due to vehicle limitations, the Orbiter will be unable to return to the launch site in a two or three engine-out scenario. Reduction of these zones requires accurate knowledge of the aerodynamic forces and moments to better assess the structural capability of the vehicle. An interesting aspect of the contingency abort trajectories is that the Orbiter would need to achieve angles of attack as high as 60deg. Such steep attitudes are much higher than those for a nominal flight trajectory. The Orbiter is currently flight certified only up to an angle of attack of 44deg at high Mach numbers and has never flown at angles of attack larger than this limit. Contingency abort trajectories are generated using the data in the Space Shuttle Operational Aerodynamic Data Book (OADB) [2]. The OADB, a detailed document of the aerodynamic environment of the current Orbiter, is primarily based on wind-tunnel measurements (over a wide Mach number and angle-of-attack range) extrapolated to flight conditions using available theories and correlations, and updated with flight data where available. For nominal flight conditions, i.e., angles of attack of less than 45deg, the fidelity of the OADB is excellent due to the availability of flight data. However, at the off-nominal conditions, such as would be encountered on contingency abort trajectories, the fidelity of the OADB is less certain. The primary aims of a recent collaborative effort (completed in the year 2001) between NASA and Boeing were to determine: 1) accurate distributions of pressure and shear loads on the Orbiter at select points in the contingency abort trajectory space; and 2) integrated aerodynamic forces and moments for the entire vehicle and the control surfaces (body flap, speed brake, and elevons). The latter served the useful purpose of verification of the aerodynamic characteristics that went into the generation of the abort trajectories.

Prabhu, Dinesh K.↗

NASA NTRS2003

In-Space Propulsion Program Overview and Status

NASA's In-Space Propulsion (ISP) Program is designed to develop advanced propulsion technologies that can enable or greatly enhance near and mid-term NASA science missions by significantly reducing cost, mass, and/or travel times. These technologies include: Solar Electric Propulsion, Aerocapture, Solar Sails, Momentum Exchange Tethers, Plasma Sails and other technologies such as Advanced Chemical Propulsion. The ISP Program intends to develop cost-effective propulsion technologies that will provide a broad spectrum of mission possibilities, enabling NASA to send vehicles on longer, more useful voyages and in many cases to destinations that were previously unreachable using conventional means. The ISP approach to identifying and prioritizing these most promising technologies is to use mission and system analysis and subsequent peer review. The ISP program seeks to develop technologies under consideration to Technology Readiness Level (TRL) -6 for incorporation into mission planning within 3-5 years of initiation. The NASA TRL 6 represents a level where a technology is ready for system level demonstration in a relevant environment, usually a space environment. In addition, maximum use of open competition is encouraged to seek optimum solutions under ISP. Several NASA Research Announcements (NRA's) have been released asking industry, academia and other organizations to propose propulsion technologies designed to improve our ability to conduct scientific study of the outer planets and beyond. The ISP Program is managed by NASA Headquarters Office of Space Science and implemented by the Marshall Space Flight Center in Huntsville, Alabama.

Wercinski, Paul F.↗

NASA NTRS1998

Preliminary Assessment of a Neptune Aerocapture Mission Using an Integrated Design Tool

Aerocapture is an efficient orbit insertion technique that uses the planet's atmosphere to decelerate an arriving spacecraft. With current technology and for vehicles of reasonable mass, it is the only technique that might deliver the high delta-V's required for insertion to orbits around the outer planets. Preliminary design studies for outer planet orbital missions must evaluate aerocapture strategies, and must therefore consider the coupling between vehicle geometry, aerodynamics, aerocapture trajectory, heating and thermal protection system mass. The analyses have been linked into an integrated design environment, with the critical parameters grouped in a global database. The designer is free to use single point evaluations, parametric variation, and numerical optimization to evaluate a range of vehicle shapes and insertion trajectories. The application of this design tool to a preliminary study for Neptune aerocapture has implications for the use of such computational environments for any atmospheric entry mission.

Gage, Peter J.↗

NASA NTRS1998

Arc Jet Flow Properties Determined from Laser-Induced Fluorescence of Atomic Nitrogen

An laser-spectroscopic investigation of the thermocheMical state of arcjet flows is currently being conducted in the Aerodynamic Heating Facility (AHF) Circlet at NASA Ames Research Center. Downstream of the nozzle exit, but upstream of the test article, Laser-Induced Fluorescence (LIF) of atomic nitrogen is used to assess the nonequilibriuM distribution of flow enthalpy in the free stream. The two-photon LIF technique provides simultaneous measurements of free stream velocity, translational temperature, and nitrogen number density on the flow centerline. Along with information from facility instrumentation, these measurements allow a determination of the free stream total enthalpy, and its apportionment in to thermal, kinetic, and chemical mode contributions. Experimental results are presented and discussed for two different niti-ogen/argon test gas flow runs during which the current is varied while the pressure remains constant .

Fletcher, Douglas↗

NASA NTRS1997

Outer Planet Mission Studies Neptune Aerocapture

Current and previous studies of orbiter missions to the outer planets have clearly identified high-energy aerocapture as a critical and enabling technology. Aerocapture involves the use of aerodynamic lift to fly a trajectory through a planet's atmosphere to sufficiently decelerate an entry vehicle to capture into planetary orbit. In the past, numerous studies of different configurations of lifting entry vehicles were studied for various planetary orbiter missions which identified aerocapture as a feasible concept yet complex and technically challenging. In order to determine the feasibility of high-speed aerocapture at the outer planets, an accurate trajectory simulation of the flight vehicle is the critical first step in the proposed research. Vehicle response to aerodynamic loading must be predicted accurately in the trajectory simulations. For several Neptune orbiter missions currently under study at the Jet Propulsion Laboratory (JPL), entry velocities relative to the rotating atmosphere ranging from 25 to 30 km/sec, are to be expected. Preliminary trajectory analysis has identified the various flow regimes the entry vehicle is expected to fly in the 8 1% H2 and 19% He atmosphere of Neptune. The size and mass of the vehicle are also determined by the launch vehicle constraints and orbiter spacecraft requirements. For a given baseline arrival conditions of an inertial entry velocity of 28 km/sec and an entry mass of 400 kg, a medium lift (L/D = 1), axisymmetric biconic shaped vehicle was selected in order to satisfy entry corridor width requirements expected for Neptune aerocapture. The analysis summarized in this study indicates that a biconic entry vehicle is a feasible concept for a Neptune aerocapture orbiter mission. The preliminary entry trajectory simulations has demonstrated adequate entry corridor control authority. Furthermore, estimates of the stagnation point heating environment has enabled the preliminary selection of candidate lightweight ceramic TPS materials.

Wercinski, Paul F.↗

NASA NTRS1997

JAE: A Jupiter Atmospheric Entry Probe Heating Code

The strong gravitational attraction of Jupiter on probes approaching the planet results in very high atmospheric entry velocities. The values relative to the rotating atmosphere can vary from about 47 to 60 km/sec, depending on the latitude of the entry. Therefore, the peak heating rates and heat shield mass fractions exceed those for any other atmospheric entries. For example, the Galileo probe's heat shield mass fraction was 50%, of which 45% was devoted to the forebody. Although the Galileo probe's mission was very successful, many more scientific questions about the Jovian atmosphere remain to be answered and additional probe missions are being planned. Recent developments in microelectronics have raised the possibility of building smaller and less expensive probes than Galileo. Therefore, it was desirable to develop a code that could quickly compute the forebody entry heating environments when performing parametric probe sizing studies. The Jupiter Atmospheric Entry (JAE) code was developed to meet this requirement. The body geometry consists of a blunt-nosed conical shape of arbitrary nose and base radius and cone angles up to about 65 deg at zero angle of attack.

Wercinski, Paul F.↗

NASA NTRS1995

Multi-Line Gamma-Ray Spectrometer Performance of a Si(Li) Detector Stack

Experimental data is presented which for the first time displays multi-line spectrometer performance of a Si(Li) detector stack at elevated temperature. The stack consists of four elements, each with a 2 cm diameter active area. Ba-133 and Ag-110m spectra are obtained using various techniques to enhance the peak-to-background ratio. Spectral data are shown as a function of temperature (94 K less than or equal to T less than or equal to 230 K) using optimized peak shaping.

Hubbard, G. Scott↗

NASA NTRS1995

Multi-Line Gamma-Ray Spectrometer Performance of a Si(Li) Detector Stack

Experimental data is presented which for the first time displays multi-line spectrometer performance of a Si(Li) detector stack at elevated temperature. The stack consists of four elements, each with a 2 cm diameter active area. Ba-133 and Ag-110m spectra are obtained using various techniques to enhance the peak-to-background ratio. Spectral data are shown as a function of temperature (94 K less than or = T less than or = 230 K) using optimized peak shaping.

Hubbard, G. Scott↗

NASA NTRS1994

Mars Sample Return: A Low Cost, Direct and Minimum Risk Design

Current NASA strategy for Mars exploration is seeking simpler, cheaper, and more reliable missions to Mars. This requirement has left virtually all previously proposed Mars Sample Return (MSR) missions as economically untenable. The MSR mission proposed in this paper represents an economical, back-to-basics approach of mission design by leveraging interplanetary trajectory design and limited surface science for shorter mission duration, advanced propulsion and thermal protection systems for mass reduction and simplified mission operations for high reliability. As a result, the proposed concept, called the Fast, Mini, Direct Mars Sample Return (FMD-MSR) mission represents the cheapest and fastest class of missions that could return a 0.5 kg sample from the surface of Mars to Earth with a total mission duration of less than 1.5 Earth years. The constraints require an aggressive mission design that dictates the use of advanced storable liquid propulsion systems and advanced TPS materials to minimize aeroshell mass. The mission does not have the high risk operations of other MSR missions such as orbit rendezvous at Mars, propulsive insertion at Mars, rover operations on the surface, and sample transfer. This paper details the key mission elements for such a mission and presents a feasible and cost effective design.

Wercinski, Paul F.↗