摘要:

Because of the healt hazards of solar activity, human traffic in deep space will require facilities for monitoring, predicting, and altering the astronauts to potential danger. This suggests a ‘‘solar watch’’ program consisting of a network of platforms at one A.U. from the Sun, capable of monitoring its global behavior. The instrumentation carried by these network platforms can evolve in sophistication with successive launches, in order to lead to a deep understanding of the physical mechanisms of solar activity — the best basis for maximally reliable activity forecasts. The possibility of steroscopic viewing of the solar surface and corona will confer unique advantages for the physical understanding of these physical mechanisms.

ISSN:0094-243X    

DOI:10.1063/1.39324

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A number of important particle astrophysics and cosmic ray experiments can be carried out at a lunar base which are impossible or impractical on the earth or in earth orbit:i) A measurement of the cosmic ray spectrum and composition in the 1014to 1016eV/nucleus region is crucial for the understanding of high energy cosmic ray sources and energetic particle acceleration mechanisms, but requires detectors too large and massive to be lifted into earth orbit. A calorimeter on the moon could provide the large area and detector mass required by using lunar soil for the bulk of the detector mass, and lifting only the active detector components and support structure from the earth. A lunar base calorimeter may be the only feasible way to do this important experiment.ii) Observation of heavy neutrinos or the products of WIMP annihilations would be of fundamental importance to particle physics and cosmology.Such observations are probably impossible on earth (where the terrestrial atmosphere produces too much background). At a lunar site, the rock itself acts as a target for upward‐moving neutrinos; these then produce secondary muons which are observed as they continue moving upward through the detector.iii) Ultraheavy cosmic ray, isotope, and antimatter studies will shed light on nucleosynthesis processes and the properties of the interstellar medium, and will require large area detectors in a low magnetic field.iv) And observaition of high energy gamma ray sources in the currently unexplored 5–200 GeV window may be able to take advantage of the presence of a (sufficiently large) lunar base water supply at very little additional cost.

ISSN:0094-243X    

DOI:10.1063/1.39352

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Promising experiments from the Moon using particle detectors are discussed, noting the advantage of the large flux collecting powerPc∼A&OHgr;t(m2‐sr‐years) offered by the remote, stable environment of a lunar base. An observatory class of particle experiments is presented, based upon proposals at NASA’s recent Stanford workshop. They vary from neutrino astronomy, particle astrophysics, and cosmic ray experiments to space physics and fundamental physics experiments such as proton decay and ‘‘table‐top’’ arrays. This research is background‐limited on Earth, and it is awkward and unrealistic in Earth orbit. It is particularly suited for the Moon wherePccan be quite large and the instrumentation is not subject to atmospheric erosion as it is (for larget) in low Earth orbit.

ISSN:0094-243X    

DOI:10.1063/1.39353

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A passive, large‐area experiment for the detection of cosmic ray actinides on the lunar surface is discussed. Due to the absence of a geomagnetic cutoff, a 100 m2array of nuclear‐track‐detecting glass plates in 5 years will detect ∼300–1000 U and Th cosmic ray nuclei of energies≳0.85 GeV/u (compared to the present world’s total of 4 actinides). With a charge resolution at uranium of ∼0.25 e, the U/Th ratio can be accurately determined, thereby dating the r‐process component of the cosmic rays; the presence of a fresh r‐process component would be corroborated by the likely detection of transuranics as well. In addition, abundances in the Pt/Pb and sub‐Pt/Pb regions and abundances of secondary actinides would provide detailed data on the 0‐1 g/cm2region of the cosmic ray path length distribution, hence on the astrophysical site of origin of these cosmic rays. Finally, should a fresh r‐process component exist, the detection of postulated superheavy nuclei is conceivale. With an analysis station at the Lunar Base, glass plates could periodically be harvested, analyzed, annealed/remelted, and replaced onto the lunar surface.

ISSN:0094-243X    

DOI:10.1063/1.39354

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We describe the current status of the search for proton decay on Earth, emphasizing the decay modeP→K+&ngr;¯ and discuss the possibility of detecting this mode with a simple detector on a lunar base station uisng the Lunar material for the bulk of the detector. The same detector could be used to search for neutrino bursts from distant supernova using the neutral current signature &ngr;&mgr;,&ngr;+N→n+&ngr;xby detecting the produced neutrons. The key problem is the development of very low mass sensitive detector elements to transport to the moon. The detection of supernova neutrinos will provide new insights into the mechanism of stellar collapse.

ISSN:0094-243X    

DOI:10.1063/1.39355

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A Laser‐Interferometer Gravitational‐Wave Observatory (LIGO) is planned for operation in the United States, with two antennas separated by several thousand kilometers. Each antenna would incorporate laser interferometers with 4 km arm lengths, operating in vacuum. The frequency range covered initially would be from a few tens of Hz to a few kHz, with possible extension to lower frequencies later. Similar systems are likely to be constructed in Europe, and there is a possibility of at least one system in Asia or Australia. It will be possible to determine the direction to a gravitational wave source by measuring the difference in the arrival times at the various antennas for burst signals or the phase difference for short duration nearly periodic signals. The addition of an antenna on the Moon, operating in support of the Earth‐based antennas, would improve the angular resolution for burst signals by about a factor 50 in the plane containing the source, the Moon, and the Earth. This would be of major importance in studies of gravitational wave sources. There is also a possibility of somewhat lower noise at frequencies near 1 Hz for a lunar gravitational wave antenna, because of lower gravity gradient noise and microseismic noise on the Moon. However, for frequencies near 0.1 Hz and below, a 107km laser gravitational wave antenna in solar orbit would be much more sensitive.

ISSN:0094-243X    

DOI:10.1063/1.39356

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The location at a lunar base of an additional laser ranging retroreflector package and a tracking becon would result in increased ranging accuracy through augmentation of the data rate and for more uniform coverage through the lunar cycle. However, an even more attractive approach would be to place a combination of small microwave and optical transponders on the moon. This could improve the lunar ranging accuracy by nearly two orders of magnitude and also simplify the measurements.The K‐band microwave transponders would be operated at the lunar base and at two remote sites to permit much improved lunar libation and tidal displacement measurements. When simultaneous measurements to the three transponders are made from an observatory on the Earth, the range errors due to the uncertainties in the tropospheric and ionospheric propagation corrections will be the same to roughly 1%, and thus will nearly cancel out in the libration and tide measurements. A two‐wavelength laser transponder also would be operated at the lunar base so that accurate tropospheric propagation corrections can be made. This would make possible major improvements in measurements of the lunar orbit and of the Earth’s rotation, as well as in tests of general relativity.

ISSN:0094-243X    

DOI:10.1063/1.39357

出版商:AIP    

年代:1990

数据来源: AIP