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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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At least 145 records · Page 8
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NASA NTRS1974

Apollo 16: Core 60004 - Preliminary study of less than 1 mm fines

The article studies the possible variation of mineralogy as a function of both grain size and depth within the core of less than 1 mm fines, for the core section 60004 from Apollo 16. Twelve samples of the fines were dry sieved. The grain size analysis showed a bimodal distribution for all samples, indicating a competing process of grain size degeneration and agglutinate formation. Approximately 99% of the minerals in the samples examined consisted of plagioclase feldspar, pyroxene and olivine, with plagioclase the dominant phase. The various minerals were analyzed, using standard electron microprobe techniques, as a function of size range for each sample, and the representative analyses are presented. Several types of glass were also analyzed, ranging in color from orange through yellow and green to colorless. The investigation of the chemical variations of mineral and lithic clasts from the top and the bottom of the core suggests that although minor variations are present, the regolith was derived from fairly homogeneous sources.

Meyer, H. O. A.↗
NASA NTRS1972

Apollo lunar surface experiments package

Developments in the ALSEP program are reported. A summary of the status for the total ALSEP program is included. Other areas discussed include: (1) status of Apollo 16 (array D) and Apollo 17 (array E), (2) lunar seismic profiling experiment, (3) lunar ejecta and meteorites experiment, and (4) lunar mass spectrometer experiments.

Source record↗
NASA NTRS2014

Forward Bay Cover Separation Modeling and Testing for the Orion Multi-Purpose Crew Vehicle

Spacecraft multi‐body separation events during atmospheric descent require complex testing and analysis to validate the flight separation dynamics model and to verify no recontact. NASA Orion Multi‐Purpose Crew Vehicle (MPCV) teams examined key model parameters and risk areas to develop a robust but affordable test campaign in order to validate and verify the Forward Bay Cover (FBC) separation event for Exploration Flight Test‐1 (EFT‐1). The FBC jettison simulation model is highly complex, consisting of dozens of parameters varied simultaneously, with numerous multi‐parameter interactions (coupling and feedback) among the various model elements, and encompassing distinct near‐field, mid‐field, and far‐field regimes. The test campaign was composed of component‐level testing (for example gas‐piston thrusters and parachute mortars), ground FBC jettison tests, and FBC jettison air‐drop tests that were accomplished by a highly multi‐disciplinary team. Three ground jettison tests isolated the testing of mechanisms and structures to anchor the simulation models excluding aerodynamic effects. Subsequently, two air‐drop tests added aerodynamic and parachute parameters, and served as integrated system demonstrations, which had been preliminarily explored during the Orion Pad Abort‐1 (PA‐1) flight test in May 2010. Both ground and drop tests provided extensive data to validate analytical models and to verify the FBC jettison event for EFT‐1, but more testing is required to support human certification, for which NASA and Lockheed Martin are applying knowledge from Apollo and EFT‐1 testing and modeling to develop a robust but affordable human spacecraft capability.

Ali, Yasmin↗
NASA NTRS1971

Test and evaluation of Apollo 14 composite casting demonstration specimens 6, 9, and 12, phase 1

Flight and control specimens 6, 9, and 12 from the Apollo 14 composite casting demonstration were evaluated with respect to the degree of dispersion achieved for mixtures of immiscible materials under one-gravity and low gravity environments. The flight and control capsules 6, 9, and 12 contained paraffin and sodium acetate; paraffin, sodium acetate and argon; and paraffin, sodium acetate and 100 micrometer diameter tungsten microspheres, respectively. The evaluation and documentation utilized photographic and microstructure examinations, density measurements, and droplet size and distribution determinations. In addition, theoretical analyses were performed in order to aid in the understanding of the fluid behavior of the specimens during processing and subsequent solidification. A comparison of evaluated data with the theoretical analyses reveals that although the immiscible materials were uniquely dispersed in a low gravity environment, nonuniform dispersions were obtained primarily due to insufficient initial mixing and an essentially unidirectional thermal gradient during cooldown.

Reger, J. L.↗
NASA NTRS2004

Rocket Exhaust Cratering: Lessons Learned from Viking and Apollo

During the Apollo and Viking programs NASA expended considerable effort to study the cratering of the regolith when a rocket launches or lands on it. That research ensured the success of those programs but also demonstrated that cratering will be a serious challenge for other mission scenarios. Unfortunately, because three decades have elapsed since NASA last performed a successful retro-rocket landing on a large planetary body - and ironically because Apollo and Viking were successful at minimizing the cratering effects - the space agency has a minimized sense of the seriousness of the issue. The most violent phase of a cratering event is when the static overpressure of the rocket exhaust exceeds the bearing capacity of the soil. This bearing capacity failure (BCF) punches a small and highly concave cup into the surface. The shape of the cup then redirects the supersonic jet - along with a large flux of high-velocity debris - directly toward the spacecraft. This has been observed in terrestrial experiments but never quantified analytically. The blast from such an event will be more than just quantitatively greater than the cratering that occurred in the Apollo and Viking programs. It will be qualitatively different, because BCF had been successfully avoided in all those missions. In fact, the Viking program undertook a significant research and development effort and redesigned the spacecraft specifically for the purpose of avoiding BCF [1]. (See Figure 1.) Because the Apollo and Viking spacecraft were successful at avoiding those cratering effects, it was unnecessary to understand them. As a result, the physics of a BCF-driven cratering event have never been well understood. This is a critical gap in our knowledge because BCF is unavoidable in the Martian environment with the large landers necessary for human exploration, and in Lunar landings it must also be addressed because it may occur depending upon the design specifics of the spacecraft and the weakening of the regolity by gas diffusion.

Metzger, Philip T.↗
NASA NTRS1971

Study of an evolutionary interim earth orbit program

An evolutionary, gradual, and step-wise spacecraft systems technology development from those used on the Apollos and Skylab 1 to that required for the space station was considered. The four mission spacecraft were dry workshop versions of the Saturn 4-B stage, and each individually configured, outfitted and launched by INT-21 vehicles. These spacecraft were evaluated for crews of three, six and nine men and for mission lifetimes of one year. Two versions of the Apollo CSM, a three man and a four man crew, were considered as the logistic vehicle. The solar cell electrical power system of the first mission evolves into a light weight panel system supplemented by an operating isotope-Brayton system on the later missions. The open life support system of the first mission evolves to a system which recovers both water and oxygen on the last mission. The data handling, communications, radiation shielding, micrometeoroid protection, and orbit keeping systems were determined. The program costs were estimated and, excluding operational costs, the cost for each mission would average about $2 billion of which one-sixth would be for development, one-fourth for experiments, and the balance for vehicle acquisition.

Anderson, J. L.↗
NASA NTRS1993

Lunar base habitat designs: Characterizing the environment, and selecting habitat designs for future trade-offs

A survey of distinct conceptual lunar habitat designs covering the pre- and post-Apollo era is presented. The impact of the significant lunar environmental challenges such as temperature, atmosphere, radiation, soil properties, meteorites, and seismic activity on the habitat design parameters are outlined. Over twenty habitat designs were identified and classified according to mission type, crew size; total duration of stay, modularity, environmental protection measures, and emplacement. Simple selection criteria of (1) post-Apollo design, (2) uniqueness of the habitat design, (3) level of thoroughness in design layout, (4) habitat dimensions are provided, and (5) materials of construction for the habitat shell are specified, are used to select five habitats for future trade studies. Habitat emplacement scenarios are created to examine the possible impact of emplacement of the habitat in different locations, such as lunar poles vs. equatorial, above ground vs. below ground, etc.

Ganapathi, Gani B.↗
NASA NTRS2013

Rover-Based Instrumentation and Scientific Investigations During the 2012 Analog Field Test on Mauna Kea Volcano, Hawaii

Rover-based 2012 Moon and Mars Analog Mission Activities (MMAMA) were recently completed on Mauna Kea Volcano, Hawaii. Scientific investigations, scientific input, and operational constraints were tested in the context of existing project and protocols for the field activities designed to help NASA achieve the Vision for Space Exploration [1]. Several investigations were conducted by the rover mounted instruments to determine key geophysical and geochemical properties of the site, as well as capture the geological context of the area and the samples investigated. The rover traverse and associated science investigations were conducted over a three day period on the southeast flank of the Mauna Kea Volcano, Hawaii. The test area was at an elevation of ~11,500 feet and is known as "Apollo Valley" (Fig. 1). Here we report the integration and operation of the rover-mounted instruments, as well as the scientific investigations that were conducted.

Graham, L. D.↗
NASA NTRS1979

Earth-crossing asteroids - Orbital classes, collision rates with earth, and origin

Asteroids that can intersect the orbit of the earth are discussed, which include Aten asteroids (semimajor axis (a) less than 1 AU, aphelion greater than 0.983 AU), Apollo asteroids (a greater than 1 AU, perihelion less than 1.017 AU), and Amor asteroids (perihelion distance between 1.017 and 1.3 AU). The principal sources of earth-crossing asteroids appear to be extinct comet nuclei and collision fragments from regions in the main asteroid belt. The total population of earth-crossers is estimated at 13,000, of which approximately 8% are Atens, 50% are Apollos, and 40% are Amors,and the present collision rate of such asteroids with the earth is estimated at about 3.5 objects, to absolute magnitude 18, per million years.

Shoemaker, E. M.↗
NASA NTRS1993

Apollo 16 core 60013/14 as a product of path 1 and path 2 regolith evolution processes

We have made a petrographic study of 12 samples along the 62 cm profile of Apollo 16 core 60013/14 taken at Station 10 near the lunar module. The basic core description and maturity variations have been discussed earlier. This core is important because it enables a stratigraphic comparison with nearby cores 60001-7 and 60009/10. These cores form a triangle with sides 35-40 m. FMR data show a maturity-match between 60009/10 and 60013/14. Unfortunately, segments of the core 60001-7 are too disturbed for any cm scale comparison. We present new data on the grain size distribution and the modal petrography for six samples from six levels of 60013 using the same approach and rationale used for 60014. We have combined the new data with our previous data on 60014 to plot the variations of grain size distributions and grain type abundances, in the 500-1000 m and 90-150 micrometers size fractions, with depth. Agglutinate abundances match the I sub s/FeO profile and both show a significant break at a depth of about 45 cm, with lower maturity material below that point. Grain size distributions show that for all analyzed samples, the mean grain size is below 90 micrometers. The two lowest samples are somewhat more coarse-grained than the rest of the core. The break at about 45 cm is the most prominent feature of the core and was described during the initial dissection as a pronounced change in color from dark to light. It now seems clear that this break is primarily one of maturity rather than of bulk chemical composition.

Basu, A.↗
NASA NTRS2009

Lift-Off Acoustics Predictions for the Ares I Launch Pad

The vibroacoustic environment associated with large launch vehicles is of concern for the integrity of the launch complex and the vehicle itself. A large body of knowledge of this environment was developed during the early years of the missile and space flight, particularly during the Apollo program. Reference 1, prepared by Sutherland and others during that era, contains much of that knowledge. A specific process for predicting noise on and around the vehicle itself and the launcher is presented in Reference 2, prepared by Eldred, et al. Recent reviews of the process, e.g., Reference 3, have suggested some revised details but generally support the methodology in Reference 2.

Launch Pad↗
NASA NTRSDate not supplied

The Challenger disaster was caused by an Apollo decision

NASA’s view of risk changed between early Apollo and the Space Shuttle. Risk was a known serious problem at the beginning of Apollo and the risk estimates were disturbingly high. To avoid public concern, risk analysis was discontinued. Risk analysis was avoided in Shuttle, leading to an unnecessarily risky design. The immediate cause of the Challenger tragedy was the mistaken decision to launch in cold weather. The fundamental cause was the high risk of the Shuttle design. Before Challenger, management thought and testified that the probability of an accident was 1 in 100,000. After Challenger, Probabilistic Risk Analysis (PRA) found a roughly 1 in 100 chance of a Shuttle failure. The recent Orion design uses the safer Apollo approach, with a hardened capsule, launch abort escape, and the crew placed above the rocket tanks and engines. During Apollo it was estimated that, “assuming all elements from propulsion to rendezvous and life support were done as well or better than ever before, that 30 astronauts would be lost before 3 were returned safely to the Earth.” The chance of astronaut survival was only 10%. After the Apollo 1 tragedy, the awareness of risk led to an intense focus on achieving safety. “The only possible explanation for the astonishing success – no losses in space and on time – was that every participant at every level in every area far exceeded the norm of human capabilities.” During Apollo, a NASA PRA found that the chance of success was “less than 5 percent.” The NASA Administrator felt that “the numbers could do irreparable harm,” and discontinued numerical risk assessment.

Harry W Jones↗