An evaluation of the exposure in nadir observation of the JEM-EUSO mission

We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme Universe Space Observatory, on-board the Japanese Experiment Module of the International Space Station. Designed as a mission to explore the extreme energy Universe from space, JEM-EUSO will monitor the Earth’s nighttime atmosphere to record the ultraviolet light from tracks generated by extensive air showers initiated by ultra-high energy cosmic rays. In the present work, we discuss the particularities of space-based observation and we compute the annual exposure in nadir observation. The results are based on studies of the expected trigger aperture and observational duty cycle, as well as, on the investigations of the effects of clouds and different types of background light. We show that the annual exposure is about one order of magnitude higher than those of the presently operating ground-based observatories.     

Hubble Space Telescope imaging polarimetry of Mars during the 2003 opposition

We report results of polarimetric imaging observations of Mars with the Hubble Space Telescope during the 2003 opposition. Through careful calibration, the observations with the ACS camera allow measurements of the polarization degree with an absolute accuracy better than 0.5% and detection of features with polarization degree contrast as small as 0.2%. The general distribution of linear polarization parameters over the Mars disk and their dependence on phase angle and wavelength are well explained qualitatively by a combination of scattering separately by the martian surface and atmosphere. We have discovered transient polarization phenomena interpreted as clouds that are best observed in ultraviolet light. These clouds are optically thin but strongly polarizing, and their origin may be related to atmospheric ice condensation processes.     

The Burden and the Promise of Scientific Research in Difficult Times

Difficult times may drive scientists and scholars to innovate. The notion is examined through the early career of historian of science George Sarton. A new departure is proposed for the unsettling present: sending a poet, an artist and a musician to the International Space Station.     

Solar Spectral Irradiance Variability in November/December 2012: Comparison of Observations by Instruments on the International Space Station and Models

Onboard the International Space Station (ISS), two instruments are observing the solar spectral irradiance (SSI) at wavelengths from 16 to 2900 nm. Although the ISS platform orientation generally precludes pointing at the Sun more than 10?–?14 days per month, in November/December 2012 a continuous period of measurements was obtained by implementing an ISS ‘bridging’ maneuver. This enabled observations to be made of the solar spectral irradiance (SSI) during a complete solar rotation. We present these measurements, which quantify the impact of active regions on SSI, and compare them with data simultaneously gathered from other platforms, and with models of spectral irradiance variability. Our analysis demonstrates that the instruments onboard the ISS have the capability to measure SSI variations consistent with other instruments in space. A comparison among all available SSI measurements during November–December 2012 in absolute units with reconstructions using solar proxies and observed solar activity features is presented and discussed in terms of accuracy.     

Comparison of UV spectra from solar-type stars

We compare high-resolution spectra from the Sun and the four solar-type stars 16 Cyg A, 16 Cyg B, HD 32008, HD 34411 obtained with IUE in the wavelength range 2650–2930 Å. The comparison is made for peak intensities between absorption lines. At the level of accuracy of the IUE observations, the stars 16 Cyg A, 16 Cyg B, HD 34411 are indistinguishable from the Sun, in particular the Mgii resonance line profiles are identical. HD 32008 is not a solar analog but is evidently of late G to early K spectral type.Based on observations with the International Ultraviolet Explorer collected at the Villafranca Satellite Tracking Station of the European Space Agency.     

Calibrating Photometric Redshift Measurements with the Multi-channel Imager(MCI)of the China Space Station Telescope(CSST)

The China Space Station Telescope(CSST)photometric survey aims to perform a high spatial resolution(～0″.15)photometric imaging for the targets that cover a larg...     

Submillimeter observations from space: A space station submillimeter facility (SSSF)

There are many important scientific problems to be attacked in the submillimeter wavelength region including the astrophysics of star formation, the dynamics of protoplanetary systems, the physics of interstellar gas, mass loss from stars, supernovae, the chemical evolution of galaxies, the star formation rates in galaxies, the astrophysics of active galactic nuclei, the deuterium abundance in different astrophysical environments, and the distribution of the cosmic background radiation. However, to effectively explore this wavelength range requires going into space since atmospheric absorption precludes most observations from the ground. As in most areas of astronomy, the twin needs for sensitivity and high redsolution indicate use of an imaging interferometer, but the needed baselines of a few tens-of-meters require a large physical structure. The planned Space Station will provide, for the first time, a platform which is large enough to accommodate a forefront submillimeter synthesis instrument. Such a telescope would open an entirely new wavelength regime to astronomy with the attendant possibilities for unexpected new discoveries.A submillimeter array would also be technically well suited for operation on the Space Station. Second-of-are resolution at submillimeter wavelengths requires only relatively short baselines; pointing accuracy and tracking stability requirements are relatively crude being determined by the single dish size rather than the array resolution; radio frequency interference (RFI) susceptibility is very low due to the large frequency separation from normal communications bands; emissions from co-orbiting debris, dust, gas, and water vapour are uncorrelated between interferometer elements; baseline stability requirements, while severe, are less stringent than for optical/IR interferometers and can almost certainly be satisfied for existing phase correction and phaseless image restoration techniques; and the technology for the dishes, mounts, receivers, LO/IF systems, and correlators either exists or is a reasonable extrapolation of what already is available on the ground.We consider the applications and possible design of a Space Station based submillimeter array which could be mounted along the main (Y) axis of the Space Station and use orbital revolution and precession to produce high-resolution synthesis mapping in much the same way ground-based linear arrays do by Earth rotation synthesis.     

Delivery of Space Weather Information in Collaboration with the International Space Environment Service (ISES)

Studying space weather is an excellent subject for getting people interested in space science in general; therefore, it is being included as part of the education and public outreach activities being organized during the International Heliophysical Year (IHY). The general public find the subject interesting because variation in the space environment, i.e., space weather, can be related to their daily lives. The international organization concerned with space weather is called the International Space Environment Service (ISES). This organization is composed of the World Warning Agency (WWA) and 11 Regional Warning Centers (RWCs). The WWA and RWCs collect, collate, and disseminate space weather information on a regular basis. This report contains history and activities of the ISES.     

Ultraviolet extinction towards far OB associations

Stars in the Aur OB-2 and Sco OB-1 associations, located in the direction of the galactic anticenter and center, respectively, have been observed for interstellar extinction. No effects due to changes of grain composition across such large distances are seen. A star exhibiting a peculiar extinction is found in each association. The properties of the responsible dust grains are discussed in terms of a two-component dust mixture: graphite and uncoated silicates. The column density both of graphite and silicate atoms are found to be higher than in stars of the same associations exhibiting a regular UV extinction.Based on observations by the International Ultraviolet Explorer collected at the Villafranca Satellite Tracking Station of the European Space Agency.     

Determination of the rotational excitation temperature in solar type stars

The OH molecular spectrum has been identified in three solar type stars, Com, CVn, and Cet. The rotational excitation temperature from molecular line intensities of OH has been determined for these stars. The observations in high resolution were made by use of the IUE satellite.Based on observations by the International Ultraviolet Explorer collected at the Villafranca Satellite Tracking Station of the European Space Agency.     

Comments on the existence of circumstellar clouds derived from interstellar Mg observations

From observations of interstellar Mgi, ii resonance lines, Gurzadyan has proposed recently that for the majority of hot stars most of the line-of-sight gas originates in dense, circumstellar clouds. To support this conclusion, which is contrary to most current models of the interstellar gas, he has set out apparently strong theoretical arguments based on empirical evidence from the sample of stars considered. In this paper we have considered the same data and have included some additional observations of interstellar Mg lines. We suggest that an empirical relationship between Mgii equivalent width and stellar effective temperature, which is central to the model proposed by Gurzadyan, may be explained by an observational selection effect. Further, we suggest that while circumstellar material may well contribute in part to observed column densities, there is no firm evidence that most of the gas is located in circumstellar clouds.Based in part on observations by the International Ultraviolet Explorer satellite collected at the Villafranca Tracking Station of the European Space Agency.     

Microbial contamination monitoring and control during human space missions

The ubiquity and resilience of microorganisms makes them unavoidable in most environments including space habitats. The impaired immune system of astronauts in flight raises the level of concern about disease risk during human space missions and additionally these biological contaminants may affect life support systems and hardware. In this review, the microbial contamination observed in manned space stations and in particular the International Space Station ISS will be discussed, demonstrating that it is a microbiologically safe working and living habitat. Microbial contamination levels were in general below the implemented quality standards, although, occasional contamination hazard reports indicate that the current prevention and monitoring strategies are the strict minimum.     

Column densities of interstellar matter in the direction of the starκ Cas (B1 Ia)

We have studied the interstellar column densities in the direction of the star Cas with the IUE high resolution SWP spectrum so as to see the relations of element depletions with condensation temperature and compare our results with the interstellar column densities in the directions of the other B-type stars obtained with the COPERNICUS satellite.Based on the observations made by the International Ultraviolet Explorer (IUEO, and collected at the Villafranca Satellite Tracking Station of European Space Agency.     

The spectroscopic orbit of 6 Draconis

6 Dra has long been known to show small variations in radial velocity, and there is photometric and spectroscopic evidence that its spectrum is composite. We show, largely on the basis of a generous number of photoelectric radial velocities mainly obtained at Cambridge and Fick observatories, that the orbit is of mild eccentricity and has a period of 562 days and a semi-amplitude of 7 km s−1.IUE observations show that the spectrum between 1600 and 1800 ∢ is consistent with its arising from a late-A main-sequence companion Based in part on observations made with the Cambridge radial-velocity spectrometer, in part on those made with the Erwin W. Fick Observatory spectrometer, and in part on those made by the International Ultraviolet Explorer and collected at the Villafranca Satellite Tracking Station of the European Space Agency.     

Polarimetry and BVRI photometry of the potentially hazardous near-Earth Asteroid (23187) 2000 PN9

The results of V-band polarimetric observations of the potentially hazardous near-Earth Asteroid (23187) 2000 PN₉ at large phase angles are presented as well as its photometric observations in BVRI bands. Observations were made in March-April 2006 during its close approach to the Earth using the 1.82-m Asiago telescope (Italy) and the 0.7-m telescope at the Chuguevskaya Observational Station (Ukraine). We obtained polarimetric measurements at the phase angle of 115°, the largest phase angle ever observed in asteroid polarimetry. Our data show that the maximum value of the polarization phase curve reached 7.7% and occurred in the phase angle range of 90-115°. The measured values of linear polarization degree, BVRI colors and magnitude-phase dependence correspond to the S-type composition of this asteroid. Based on our observations the following characteristics of the Asteroid (23187) 2000 PN₉ were obtained: a rotation period of 2.5325±0.0004 h, a lightcurve amplitude of 0.13 mag, an albedo of 0.24±0.06 and a diameter of 1.6±0.3 km.     

Dependence on reddening of interstellar column densities in the direction of O stars

We have investigated 14 O-type stars with IUE high resolution SWP spectra in order to improve the relations of element depletions withE(B-V), and to look for other possible relations with two stellar parameters: namely, the rate of mass loss and rotational velocity. The stars were chosen so as to cover several directions in the Galaxy, as well as a wide range in interstellar reddening. Although our data are only crude and were obtained by making several approximations, they show the derived dependence of a parameter, which we call a depletion index, on reddening. We found a clear inverse trend relating the abundance of elements to interstellar reddening, and a crude relation between the increasing depletion and condensation temperature.Based on observations by the International Ultraviolet Explorer (IUE) collected at the Villafranca Satellite Tracking Station of the European Space Agency.On leave of absence from the Astronomical Department, Istanbul University.     

Column densities of Interstellar Gas in the direction of the starε Ori (B0 IA)

We have investigated the star Ori with IUE high resolution SWP spectrum in order to derive curve of growth and column densities of Al II, Si II, S II, Fe II, Ni II and Zn II. It has been possible to fit these ions on one empirical curve of growth with a velocity parameterb = 11 km s^–1 for the star studied.Based on observations made by the International Ultraviolet Explorer (IUE), and collected at the Villafranca Satellite Tracking Station of the European Space Agency.     

High-Energy Astronomy From The International Space Station

The European Space Agency, ESA, is currently studying 3 high-energy astronomy missions that use the International Space Station (ISS). These are Lobster-ISS, an all-sky imaging X-ray monitor, the Extreme Universe Space Observatory (EUSO) which will study the highest energy cosmic rays by using the Earth's atmosphere as a giant detector and XEUS — the X-ray Evolving Universe Spectroscopy Mission, a potential successor to ESA's XMM-Newton X-ray observatory. These first 2 missions will he attached to the external platforms on the Columbus module, while XEUS will visit the ISS to attach additional X-ray mirrors to enlarge the original 4.5 m diameter mirrors to the 10 m diameter required to observed redshifted iron lines from massive black holes in the early Universe. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Case For Renewed Human Exploration Of The Moon

The European Space Agency, ESA, is currently studying 3 high-energy astronomy missions that use the International Space Station (ISS). These are Lobster-ISS, an all-sky imaging X-ray monitor, the Extreme Universe Space Observatory (EUSO) which will study the highest energy cosmic rays by using the Earth's atmosphere as a giant detector and XEUS — the X-ray Evolving Universe Spectroscopy Mission, a potential successor to ESA's XMM-Newton X-ray observatory. These first 2 missions will he attached to the external platforms on the Columbus module, while XEUS will visit the ISS to attach additional X-ray mirrors to enlarge the original 4.5 m diameter mirrors to the 10 m diameter required to observed redshifted iron lines from massive black holes in the early Universe. This revised version was published online in July 2006 with corrections to the Cover Date.     

HUMAN SPACEFLIGHT: ACHIEVEMENTS, BENEFITS AND FUTURE OPPORTUNITIES FROM A EUROPEAN PERSPECTIVE

The past achievements, benefits and future opportunities of human spaceflight are discussed from a European perspective. Earlier work performed on the Skylab, Salyut, Shuttle, Spacelab, and Mir orbital facilities is reviewed, together with the prospects for new research on the International Space Station (ISS). Major scientific benefits are expected from the ISS in the areas of life science research (including human physiology and medicine) physical sciences, and fundamental physics.