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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Terrestrial quarantine considerations for unmanned sample return missions

For the purpose of understanding some of the possible implications of a terrestrial quarantine constraint on a mission and for developing a basic approach which can be used to demonstrate compliance beyond that developed for Apollo, a terrestrial quarantine study was performed. It is shown that some of the basic tools developed and used by the planetary quarantine community have applicability to terrestrial quarantine analysis. By using these tools, it is concluded that: (1) the method of biasing the earth aiming point when returning from the planet is necessary but, by itself, may not satisfy terrestrial quarantine constraints; and (2) spacecraft and container design significantly influence contamination transfer.

Hoffman, A. R.↗
NASA NTRS1974

Mars surface-to-orbit vehicles for sample return missions

Review of the results of a Mars surface-to-orbit launch vehicle study using an upgraded atmospheric density profile and an ascent trajectory optimization program. Orbit insertion was achieved with velocity losses less than those found in an earlier study. Values of thrust-to-mass ratio which minimize velocity losses for dual-burn vehicles were found to be significantly greater than the values of thrust-to-launch-mass ratio for the minimum-velocity-loss continuous-burn vehicle. The use of a two-stage solid-propellant vehicle employing a spin-stabilized second stage offers an attractive design option for a Mars surface-to-orbit launch vehicle.

Weaver, W. L.↗
NASA NTRS1980

Design integration of aerocapture and aeromaneuver vehicles for a Mars sample return mission

The concept of using an aerocapture vehicle for Mars and other planetary missions is a technology that yields significant fuel savings. This concept uses the planet's atmosphere to dissipate excess velocity of the entry vehicle allowing it to go into orbit. A conceptual design integration study of two configurations of aerocapture vehicles which can make an aerodynamically controlled entry has been made. The first configuration contains the existing Viking type Lander and an Orbiter. The second spacecraft is more general in payload and could be used to place an Orbiter and a Lander on other planets with a single aeroshell.

Hassett, R. J.↗
NASA NTRS1983

Comet flyby sample return experiment

Dust from several comets can be returned to earth with minimum propulsion effort after a high-speed encounter. The collection concept involves the capture of individual dust particles by condensation in a cell after vaporization by a thin diaphragm. This collection concept has been validated in laboratory tests. To compensate for the slower laboratory velocities in a two-stage light-gas gun, higher-density metals (Zn and Cd) have been used for particles and diaphragms to simulate hypervelocity vaporization. Teflon has proved to be a suitable material for the collection cell; more than 50 percent of the vaporized projectile material has been recovered by chemical etching from such cells. Hypervelocity-impact parameters (such as diaphragm-to-projectile ratio, hole size, and plume angles) determined by tests permit the modification of existing analytical models. These new findings are necessary for flyby cometary experiments.

Tsou, P.↗
NASA NTRS1988

Trace fossils of microbial colonization on Mars: Criteria for search and for sample return

The recent discovery of microbial trace-fossil formation in the frigid Ross Desert of Antarctica suggests that early primitive life on Mars may have left behind similar signatures. These trace fossils are apparent as chemical or physical changes in rock (or sediment) structure (or chemistry) caused by the activity of organisms. Life on Mars, if it ever existed, almost certainly did not evolve above the level of microorganisms, and this should be considered in search for fossil life. For the reasons detailed here, microbial trace fossils seem to be a better and more realistic target for search than would be true microbial fossils (remnants of cellular structures).

Friedmann, E. I.↗