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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS2009

Functional Task Test (FTT)

This slide presentation reviews the Functional Task Test (FTT), an interdisciplinary testing regimen that has been developed to evaluate astronaut postflight functional performance and related physiological changes. The objectives of the project are: (1) to develop a set of functional tasks that represent critical mission tasks for the Constellation Program, (2) determine the ability to perform these tasks after space flight, (3) Identify the key physiological factors that contribute to functional decrements and (4) Use this information to develop targeted countermeasures.

Bloomberg, Jacob J.↗
NASA NTRS2017

The Functional Task Test: Results from the One-Year Mission

Exposure to the microgravity conditions of spaceflight causes astronauts to experience alterations in multiple physiological systems including sensorimotor disturbances, cardiovascular deconditioning, and loss of muscle mass and strength. Some or all of these changes might affect the ability of crewmembers to perform critical mission tasks immediately after landing on a planetary surface. The goal of our recently completed Functional Task Test (FTT) study was to determine the effects of spaceflight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. The FTT is comprised of seven functional tests and a corresponding set of interdisciplinary physiological measures specifically targeting the sensorimotor, cardiovascular and muscular changes associated with exposure to spaceflight. Both Shuttle and International Space Station (ISS) astronauts were tested before and after spaceflight. Additionally, we conducted a supporting study in which subjects performed the FTT protocol before and after 70 days of 6 deg head-down bed rest, an analog for spaceflight. Two groups of bed rest subjects were studied: one group who performed aerobic and resistive exercise during bed rest using protocols similar to astronauts and one group who served as non-exercise controls. The bed rest analog allowed us to isolate the impact of body unloading without other spaceflight environmental factors on both functional tasks and on the underlying physiological factors that lead to decrements in performance, and then to compare those results with the results obtained in our spaceflight study. As an extension to the FTT study we collected data from one ISS crewmember who experienced 340 days in space using the same FTT protocol used previously to test spaceflight and bed rest subjects. Data were collected three times preflight and 1.7, 7.5 and 36.5 days after landing. The FTT one-year results will be presented at the meeting, and a comparison will be made with data previously obtained using the same protocol on astronauts tested before and after 6 months in space. Future work will focus on collecting data from additional subjects from one-year flights to gain a better assessment of extreme long-duration exposure to spaceflight on both functional measure of performance and physiological metrics.

Bloomberg, J. J↗
NASA NTRS1996

NSTAR Ion Thruster and Breadboard Power Processor Functional Integration Test Results

A 2.3 kW Breadboard Power Processing Unit (BBPPU) was developed as part of the NASA Solar Electric Propulsion Technology Application Readiness (NSTAR) Program. The NSTAR program will deliver an electric propulsion system based on a 30 cm xenon ion thruster to the New Millennium (NM) program for use as the primary propulsion system for the initial NM flight. The final development test for the BBPPU, the Functional Integration Test, was carried out to demonstrate all aspects of BBPPU operation with an Engineering Model Thruster. Test objectives included: (1) demonstration and validation of automated thruster start procedures, (2) demonstration of stable closed loop control of the thruster beam current, (3) successful response and recovery to thruster faults, and (4) successful safing of the system during simulated spacecraft faults. These objectives were met over the specified 80-120 VDC input voltage range and 0.5-2.3 output power capability of the BBPPU. Two minor anomalies were noted in discharge and neutralizer keeper current. These anomalies did not affect the stability of the system and were successfully corrected.

Hamley, John A.↗
NASA NTRS2008

Validation of Cardiovascular Parameters During NASA's Functional Task Test

Microgravity-induced physiological changes, including cardiovascular deconditioning may impair crewmembers f capabilities during exploration missions on the Moon and Mars. The Functional Task Test (FTT), which will be used to assess task performance in short and long duration astronauts, consists of 7 functional tests to evaluate crewmembers f ability to perform activities to be conducted in a partial-gravity environment or following an emergency landing on Earth. The Recovery from Fall/Stand Test (RFST) tests both the subject fs ability to get up from a prone position and orthostatic intolerance. PURPOSE: Crewmembers have never become presyncopal in the first 3 min of quiet stand, yet it is unknown whether 3 min is long enough to cause similar heart rate fluctuations to a 5-min stand. The purpose of this study was to validate and test the reliability of heart rate variability (HRV) analysis of a 3-min quiet stand. METHODS: To determine the validity of using 3 vs. 5-min of standing to assess HRV, 7 healthy subjects remained in a prone position for 2 min, stood up quickly and stood quietly for 6 min. ECG and continuous blood pressure data were recorded. Mean R-R interval and spectral HRV were measured in minutes 0-3 and 0-5 following the heart rate transient due to standing. Significant differences between the segments were determined by a paired t-test. To determine the reliability of the 3-min stand test, 13 healthy subjects completed 3 trials of the complete FTT on separate days, including the RFST with a 3-min stand test. Analysis of variance (ANOVA) was performed on the HRV measures. RESULTS: Spectral HRV measures reflecting autonomic activity were not different (p>0.05) during the 0-3 and 0-5 min segment (mean R-R interval: 738+/-74 ms, 728+/-69 ms; low frequency to high frequency ratio: 6.5+/-2.2, 7.7+/-2.7; normalized high frequency: 0.19+/-0.03, 0.18+/-0.04). The average coefficient of variation for mean R-R interval, systolic and diastolic blood pressures in the prone position and stand test were less than 8% for the test sessions. ANOVA results yielded a greater inter-subject variability (p.0.006) than inter-session variability (p>0.05) for HRV in the stand test. CONCLUSION: These studies show that a 3 minute stand delivers repeatable cardiovascular heart rate and BP data in the context of this larger series of tests such as the FTT.

Arzeno, N. M.↗
NASA NTRS1991

Environmental Data Recorder (EDR) qualification

Qualification testing of the environmental data recorder (EDR) was successfully completed. The purpose of this test was to qualify the EDR so that it could monitor segments shipped via railcar from Utah to Kennedy Space Center (KSC). The tests consisted of a transportation and a functional test. The transportation test verified EDR operation in its intended environment. The functional test verified EDR accuracy. Data from the functional test showed that the EDR accuracies complied with requirements. Since the EDR meets or exceeds all of its test objectives, it was successfully qualified. It is recommended that the EDR replace the transportation monitoring unit (TMU). A description of the qualification procedure is presented.

Danforth, Richard A.↗
NASA NTRS1987

Comparing the effectiveness of software testing strategies

This study compares the results of code reading, functional testing, and structural testing in three aspects of software testing: fault detection effectiveness, fault detection cost, and classes of faults detected. Thirty two professional programmers and 42 advanced students applied the three techniques to four unit-sized programs in a fractional experimental design. The major results of this study are the following: (1) With the professional programmers, code reading detected more software faults and had a higher detection rate than did functional or structural testing, while functional testing detected more faults than did structural testing, but functional and structural testing were not different in fault detection rate. (2) In one advanced student subject group, code reading and functional testing were not different in faults found, but were superior to structural testing, while in the other advanced student subject group there was no difference among the techniques. (3) With the advanced student subjects, the three techniques were not different in fault deteciton rate. (4) Number of faults observed, fault detection rate, and total effort in detection depended on the type of software tested. (5) Code reading detected more interface faults than did the other methods. (6) Functional testing detected more control faults than did the other methods. (7) When asked to estimate the percentage of faults detected, code readers gave the most accurate estimates while functional testers gave the least accurate estimates. Appendix B includes the source code for the word.

Basili, Victor R.↗
NASA NTRS2009

Validation of Cardiovascular Parameters during NASA's Functional Task Test

Microgravity exposure causes physiological deconditioning and impairs crewmember task performance. The Functional Task Test (FTT) is designed to correlate these physiological changes to performance in a series of operationally-relevant tasks. One of these, the Recovery from Fall/Stand Test (RFST), tests both the ability to recover from a prone position and cardiovascular responses to orthostasis. PURPOSE: Three minutes were chosen for the duration of this test, yet it is unknown if this is long enough to induce cardiovascular responses similar to the operational 5 min stand test. The purpose of this study was to determine the validity and reliability of heart rate variability (HRV) analysis of a 3 min stand and to examine the effect of spaceflight on these measures. METHODS: To determine the validity of using 3 vs. 5 min of standing to assess HRV, ECG was collected from 7 healthy subjects who participated in a 6 min RFST. Mean R-R interval (RR) and spectral HRV were measured in minutes 0-3 and 0-5 following the heart rate transient due to standing. Significant differences between the segments were determined by a paired t-test. To determine the reliability of the 3-min stand test, 13 healthy subjects completed 3 trials of the FTT on separate days, including the RFST with a 3 min stand. Analysis of variance (ANOVA) was performed on the HRV measures. One crewmember completed the FTT before a 14-day mission, on landing day (R+0) and one (R+1) day after returning to Earth. RESULTS VALIDITY: HRV measures reflecting autonomic activity were not significantly different during the 0-3 and 0-5 min segments. RELIABILITY: The average coefficient of variation for RR, systolic (SBP) and diastolic blood pressures during the RFST were less than 8% for the 3 sessions. ANOVA results yielded a greater inter-subject variability (p<0.006) than inter-session variability (p>0.05) for HRV in the RFST. SPACEFLIGHT: Lower RR and higher SBP were observed on R+0 in rest and stand. On R+1, both RR and SBP trended towards preflight rest and stand values. Postflight HRV showed higher LF/HF for rest and stand and lower HFnu during rest. CONCLUSION: These studies show that a 3 min stand delivers repeatable HRV data in the context of this larger series of FTT tests. Spaceflight-induced changes in blood pressure, RR and autonomic function (HRV) are evident from the RFST.

Arzeno, N. M.↗
NASA NTRS2019

Meshless Local Petrov-Galerkin (MLPG) Method with Orthogonal Polynomials for Euler-Bernoulli Beam Problems

In this paper, the feasibility of orthogonal polynomials in the meshless local Petrov Galerkin method (MLPG) method is studied. The orthogonal polynomials, Chebyshev and Legendre polynomials, are used in this MLPG method as trial functions. The test functions used were power functions with smooth derivatives at their ends. The performance of these methods is studied by applying these methods to Euler-Bernoulli beam problems. The MLPG-Galerkin and Legendre methods passed all the patch tests for simple beam problems. Next the formulations are tested on complex beam problems such as beams with partial loadings and continuous beam problems. Problems with load discontinuities and additional supports require special attention. Near discontinuities, judicious choice of number of nodes and nodal placements are needed to obtain accurate deflections, slopes, moments and shear forces. As polynomial functions are used, the large number of nodes can create a transformation matrix that is ill-conditioned, resulting in problems with the inversion of the matrix. The conditioning worsens as the number of nodes are increased beyond 20. Quadruple precision was needed for models to obtain accurate solutions. Even with quadruple precision the accuracy of the method suffers as the number of nodes is increased beyond 20. This appears to be a drawback of the MLPG-Chebyshev and MLPG-Legendre methods.

Raju, Ivatury S.↗
NASA NTRS2002

A Meshless Local Petrov-Galerkin Method for Euler-Bernoulli Beam Problems

An accurate and yet simple Meshless Local Petrov-Galerkin (MLPG) formulation for analyzing beam problems is presented. In the formulation, simple weight functions are chosen as test functions. The use of these functions shows that the weak form can be integrated with conventional Gaussian integration. The MLPG method was evaluated by applying the formulation to a variety of patch test and thin beam problems. The formulation successfully reproduced exact solutions to machine accuracy when test functions with C2 continuity and an appropriate order of basis functions are used.

Raju, I. S.↗
NASA NTRS1975

Dynamic analysis of the GEOS satellite

The assumed modes method is used to investigate the stability of the GEOS satellite. The system is discretized by representing the continuous displacement by finite series of space-dependent admissible functions multiplied by time-dependent generalized coordinates. The spatial dependence is eliminated by integration over the elastic domains, so that the testing functional reduces to a testing function. The sign properties of the testing function are then tested and the equilibrium defined as nontrivial. In considering the stability of small motions about nontrivial equilibrium, it is shown that if the analysis performed by ignoring the motion of the mass center indicates stability, then the system remains stable if the motion of the mass center is included.

Meirovitch, L.↗
NASA NTRS1974

HAL/S-360 compiler test activity report

The levels of testing employed in verifying the HAL/S-360 compiler were as follows: (1) typical applications program case testing; (2) functional testing of the compiler system and its generated code; and (3) machine oriented testing of compiler implementation on operational computers. Details of the initial test plan and subsequent adaptation are reported, along with complete test results for each phase which examined the production of object codes for every possible source statement.

Helmers, C. T.↗
NASA NTRS1979

Electrical Evaluation of RCA MWS5501D Random Access Memory, Volume 2, Appendix a

The electrical characterization and qualification test results are presented for the RCA MWS5001D random access memory. The tests included functional tests, AC and DC parametric tests, AC parametric worst-case pattern selection test, determination of worst-case transition for setup and hold times, and a series of schmoo plots. The address access time, address readout time, the data hold time, and the data setup time are some of the results surveyed.

Klute, A.↗
NASA NTRS1979

Electrical Evaluation of RCA MWS5001D Random Access Memory, Volume 3, Appendix B

The electrical characterization and qualification test results are presented for the RCA MWS5001D random access memory. The tests included functional tests, AC and DC parametric tests, AC parametric worst-case pattern selection test, determination of worst-case transition for setup and hold times, and a series of schmoo plots. The test values for the output voltage, average input current, the supply current and the leakage current are presented.

Klute, A.↗
NASA NTRS1979

Electrical Evaluation of RCA MWS5001D Random Access Memory, Volume 4, Appendix C

The electrical characterization and qualification test results are presented for the RCA MWS5001D random access memory. The tests included functional tests, AC and DC parametric tests, AC parametric worst-case pattern selection test, determination of worst-case transition for setup and hold times, and a series of schmoo plots. Statistical analysis data is supplied along with write pulse width, read cycle time, write cycle time, and chip enable time data.

Klute, A.↗
NASA NTRS1979

Electrical Evaluation of RCA MWS5001D Random Access Memory, Volume 5, Appendix D

The electrical characterization and qualification test results are presented for the RCA MWS 5001D random access memory. The tests included functional tests, AC and DC parametric tests, AC parametric worst-case pattern selection test, determination of worst-case transition for setup and hold times, and a series of schmoo plots. Average input high current, worst case input high current, output low current, and data setup time are some of the results presented.

Klute, A.↗
NASA NTRS2013

Qualification of UHF Antenna for Extreme Martian Thermal Environments

The purpose of this development was to validate the use of the external Rover Ultra High Frequency (RUHF) antenna for space under extreme thermal environments to be encountered during the surface operations of the Mars Science Laboratory (MSL) mission. The antenna must survive all ground operations plus the nominal 670 Martian sol mission that includes summer and winter seasons of the Mars thermal environment.The qualification effort was to verify that the RUHF antenna design and its bonding and packaging processes are adequate to survive the harsh environmental conditions. The RUHF is a quadrifilar helix antenna mounted on the MSL Curiosity rover deck. The main components of the RUHF antenna are the helix structure, feed cables, and hybrid coupler, and the high-power termination load. In the case of MSL rover externally mounted hardware, not only are the expected thermal cycle depths severe, but there are temperature offsets between the Mars summer and winter seasons. The total number of temperature cycles needed to be split into two regimes of summer cycles and winter cycles. The qualification test was designed to demonstrate a survival life of three times more than all expected ground testing, plus a nominal 670 Martian sol missions. Baseline RF tests and a visual inspection were performed prior to the start of the qualification test. Functional RF tests were performed intermittently during chamber breaks over the course of the qualification test. For the RF return loss measurements, the antenna was tested in a controlled environment outside the thermal chamber with a vector network analyzer that was calibrated over the antenna s operational frequency range. A total of 2,010 thermal cycles were performed. Visual inspection showed a dulling of the solder material. This change will not affect the performance of the antenna. No other changes were observed. RF tests were performed on the RUHF helix antenna, hybrid, and load after the 2,010 qualification cycles test. The RF performance of the RUHF antenna, hybrid, and load were almost identical before and after the complete test. Therefore, the developed design of RUHF is qualified for a long-duration MSL mission. The RUHF antenna has not been used for long-duration missions such as MSL in the past. The state-of-the-art technology of the RUHF antenna is used to develop the antennas for MSL mission survivability. This developmental test data provides the confidence in using this RUHF antenna for future NASA missions to Mars.

Ramesham, Rajeshuni↗