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Hills, H. K.

Publications and source records attributed to Hills, H. K..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Availability of Previously Unprocessed ALSEP Raw Instrument Data, Derivative Data, and Metadata Products

In year 2010, 440 original data archival tapes for the Apollo Lunar Science Experiment Package (ALSEP) experiments were found at the Washington National Records Center. These tapes hold raw instrument data received from the Moon for all the ALSEP instruments for the period of April through June 1975. We have recently completed extraction of binary files from these tapes, and we have delivered them to the NASA Space Science Data Cordinated Archive (NSSDCA). We are currently processing the raw data into higher order data products in file formats more readily usable by contemporary researchers. These data products will fill a number of gaps in the current ALSEP data collection at NSSDCA. In addition, we have estabilished a digital, searcheable archive of ALSEP document and metadata as part of the web portal of the Lunar and Planetary Institute. It currently holds approx. 700 documents totaling approx. 40,000 pages

ALSEP↗
NASA NTRS2015

Restoration of the Apollo Heat Flow Experiments Metadata

Geothermal heat flow probes were deployed on the Apollo 15 and 17 missions as part of the Apollo Lunar Surface Experiments Package (ALSEP). At each landing site, the astronauts drilled 2 holes, 10-m apart, and installed a probe in each. The holes were 1- and 1.5-m deep at the Apollo 15 site and 2.5-m deep at the Apollo 17 sites. The probes monitored surface temperature and subsurface temperatures at different depths. At the Apollo 15 site, the monitoring continued from July 1971 to January 1977. At the Apollo 17 site, it did from December 1972 to September 1977. Based on the observations made through December 1974, Marcus Langseth, the principal investigator of the heat flow experiments (HFE), determined the thermal conductivity of the lunar regolith by mathematically modeling how the seasonal temperature fluctuation propagated down through the regolith. He also determined the temperature unaffected by diurnal and seasonal thermal waves of the regolith at different depths, which yielded the geothermal gradient. By multiplying the thermal gradient and the thermal conductivity, Langseth obtained the endogenic heat flow of the Moon as 21 mW/m(exp 2) at Site 15 and 16 mW/m(exp 2) at Site 17.

HFE metadata↗
NASA NTRS1991

The Apollo lunar surface water vapor event revisited

On March 7, 1971, the first sunrise following the Apollo 14 mission, the Suprathermal Ion Detector Experiment (SIDE) deployed at the Apollo 14 site reported an intense flux of ions whose mass per charge was consistent with water vapor. The amount of water is examined, and the various acceleration processes, responsible for accelerating ions into the SIDE, are discussed. It is concluded that during most of the event the observed water vapor ions were accelerated by the negative lunar surface electric potential and, secondly, that this event was probably the result of mission associated water vapor, either from the LM ascent and descent stage rockets or from residual water in the descent stage tanks.

Freeman, J. W., Jr.↗
NASA NTRS1990

World-wide interactive access to scientific databases via satellite and terrestrial data network

In order to demonstrate the possibilities for scientific networking and data transfer, a first temporary satellite network link was installed between Czecholovakia and the European space operations center in Darmstadt, during the meeting of the inter-agency consultative group for space science in Prague. Several experiments to show interactive nature of the facility and the capability of the system were carried out, and it was proven that, despite the temporary nature of the installation, the planned demonstrations could be conducted in real time. Demonstrations included electronic mail message, orbit prediction and solar X-ray data. The results of the experiment provided insight into possibilities of data exchange.

Sanderson, T. R.↗
NASA NTRS1984

Launch summary for 1978 - 1982

Data pertinent to the launching of space probes, soundings rockets, and satellites presented in tables include launch date, time, and site; agency rocket identification; sponsoring country or countries; instruments carried for experiments; the peak altitude achieved by the rockets; and the apoapsis and periapsis for satellites. The experimenter or institution involved in the launching is also cited.

Hills, H. K.↗
NASA NTRS1979

Long term magnetospheric particle variations (1 day T infinity), appendix 2

Effects of solar variations on energetic particle propagation are discussed, as well as prediction techniques for such particles within the magnetosphere. Magnetic field models, magnetic energy stored in the tail, magnetic monitoring measurements in the geostationary orbit and at certain ground based stations are important elements concerning improving such techniques.

Vette, J. I.↗
NASA NTRS1979

Occurrence of the lobe plasma at lunar distance

Recent analysis has confirmed the existence of the lobe plasma, the extension of the 'boundary layer' and 'plasma mantle' to lunar distances. The observation of the lobe plasma is strongly correlated with the y component of the IMF. Generally, the lobe plasma is observed sporadically for a full day after the moon has entered the tail and a full day before the last magnetopause crossing as it exits the tail. An average extent of approximately 8-10 earth radii inward from the magnetopause is inferred; however, the lobe plasma has been seen all across the tail.

Hardy, D. A.↗
NASA NTRS1978

Transport of terrestrial atmospheric gases to the moon

The suprathermal Ion Detector Experiment instruments on the lunar surface have identified fluxes of ions which may be different from the solar wind both in elemental and in isotopic abundances. At present, only O/+/ is (tentatively) identified, but the mechanism operates to produce ions at the moon which have their origin in the earth's atmosphere. Consequently, the 'solar wind' component of the surface-correlated gases is effectively a combination of terrestrial atmospheric ions and the actual solar wind. The results differ from solar wind results if the terrestrial ion abundances strongly differ from those of the solar wind.

Hills, H. K.↗
NASA NTRS1977

Double-peaked ion spectra in the lobe plasma - Evidence for massive ions

Suprathermal Ion Detector Experiments (SIDE) have suggested the presence of a significant secondary peak in the ion distribution function during geomagnetic active periods when the moon is within the lobe plasma. It is observed that: (1) an increase in the primary peak bulk velocity is reflected in an increase in secondary peak bulk velocity, (2) both spectra are narrow in the instrument-look direction (assumed parallel to the flow) and peak temperatures are usually less than about 10 eV, (3) periods for double peak observations comprise about 10% of the total lobe plasma observation time, (4) assuming that peaks are caused by protons, and without correcting for lunar surface potential, primary peak bulk velocity is between about 70 and 160 km/s, and secondary peak bulk velocity is between about 360 and 840 km/s, and (5) assuming equal flow velocities outside the influence of the lunar surface potential are equal for the ions of the two peaks, and making corrections for this potential, secondary peak ions are consistent with N(+) or O(+), and the ratio of O(+) to proton number densities is usually less than about 2 x 10 to the -3rd.

Hardy, D. A.↗
NASA NTRS1977

Heavy ion circulation in the earth's magnetosphere

A mechanism for heavy ion circulation in the magnetosphere is proposed. Singly charged ions heavy ions from the plasmasphere are convected intermittently to the dayside magnetopause, accelerated there, swept into the distant tail lobes and boundary layer, and convected earthward in the plasma sheet to reenter the magnetosphere.

Freeman, J. W.↗
NASA NTRS1976

Low-energy-proton regime in the geomagnetic tail at lunar distance

The reported investigation makes use of data obtained with the aid of the suprathermal ion detector experiment (SIDE) that is being conducted with instruments which were placed on the moon during the Apollo lunar landings. The moon traverses the geomagnetic tail once each month. Observations of a new low-energy plasma regime in the tail are presented. It is pointed out that the new regime lies within the magnetosphere, but outside the plasma sheet. According to the mass analyzer data of SIDE, the observed low-energy fluxes could consist entirely of protons. However, there might be an admixture of ions of greater mass.

Hills, H. K.↗
NASA NTRS1975

Bow shock protons in the lunar environment

Protons from the earth's bow shock are observed by the suprathermal ion detector experiment (SIDE) in two regions of the lunar orbit. The dawn region begins at the dawn-side bow-shock crossing and ends about 5 days later, the dusk region begins at about 2 days prior to entering the dusk-side magnetosheath and ends at the inbound bow-shock crossing. Dusk and dawn refer to a terrestrial coordinate system. The dominant contribution to the ion spectra observed by the SIDE in these regions is from particles with energies between about 750 eV/q and 3500 eV/q. Analysis of simultaneous data from the Explorer 35 magnetometer and the SIDE indicates that the observability of bow-shock protons at the lunar distance is dependent on the configuration of the interplanetary magnetic field.

Benson, J.↗
NASA NTRS1975

A new plasma regime in the distant geomagnetic tail

Observations are reported of an extensive region of low-energy plasma particles (LEP) flowing antisunward along the ordered field lines in the lobes of the geomagnetic tail at lunar distances. The flow was detected by three suprathermal ion detectors deployed on the lunar surface during the Apollo 12, 14, and 15 missions. This particle regime is found to be similar to the 'boundary layer' and 'plasma mantle' observed at smaller geocentric distances and to an interior flow region parallel to the magnetopause in the dayside magnetosphere. It is located exterior to the plasma sheet across essentially the entire tail and adjacent to the magnetopause on both the dawn and dusk sides of the magnetosphere. Variations in the integral flux, temperature, and number density are described. It is suggested that this flow and the three similar regimes are simply connected along the inner surface of the magnetopause and are, in fact, the same phenomenon.

Hardy, D. A.↗
NASA NTRS1975

Solar cosmic ray 'square wave' of August 1972

Three Rice University suprathermal ion detector experiments (sides) were deployed on the lunar surface during the Apollo 12, 14, and 15 missions. During the exceptional period of solar activity in August 1972, penetrating particles were observed by all side detectors on the night side of the moon. The penetrating particles are tentatively identified as solar protons with energies (approximately 25 MeV or greater) that were able to penetrate the shielding of all detectors. Of particular interest is the occurrence on August 5 of a 'square wave' flux enhancement of 2-hour duration. Data from a variety of ground-based and space experiments are examined in relation to the square wave. Based on the results of this investigation a model relating the square wave to the flare plasma propagation is proposed. This model hypothesizes transport of energetic particles along a 'corridor' formed by the tangential discontinuity produced by the driver gas of a flare-induced shock wave. This model could explain other frequently observed delayed particle events.

Medrano, R. A.↗
NASA NTRS1975

The lunar terminator ionosphere

The extended ionosphere is seen by the Suprathermal Ion Detector Experiments (SIDE) near the terminator. An analysis of the energy and mass spectra of these ions accelerated by the interplanetary electric field indicates the following: (1) the principal ion species are in the mass per unit charge ranges consistent with neon and argon, (20-28 and 40-44 amu/q); (2) the lunar atmosphere in these mass ranges is distributed exponentially; (3) the terminator region surface number density for Ne-20 is of the order of 10 to the 5th/cu cm; (4) the terminator region lunar surface potential is negative from about 10 to 100 volts; and (5) this potential has a screening length of the order of a kilometer.

Benson, J.↗
NASA NTRS1973

Electric potential of the moon in the solar wind.

Acceleration and detection of the lunar thermal ionosphere in the presence of the lunar electric field yields a value of at least +10 V for the lunar electric potential for solar zenith angles between approximately 20 and 45 deg and in the magnetosheath or solar wind. An enhanced positive ion flux is observed with the Apollo Lunar Surface Experiments Package Suprathermal Ion Detector Experiment when a preacceleration voltage attains certain values. This enhancement is greater when the moon is in the solar wind as opposed to the magnetosheath.

Freeman, J. W., Jr.↗