Search Publications
Optical tracking of deep-space spacecraft in Halo L2 orbits and beyond: The Gaia mission as a pilot case
Buzzoni, Alberto; Altavilla, Giuseppe; Galleti, Silvia
We tackle the problem of accurate optical tracking of distant man-made probes, on Halo orbit around the Earth-Sun libration point L2 and beyond, along interplanetary transfers. The improved performance of on-target tracking, especially when observing with small-class telescopes is assessed providing a general estimate of the expected S/N ratio in …
Quasi-continuous reconnection accompanied by FTEs during IMF Bz ≈ 0 nT observed by Double Star TC-1 at the dawnside magnetopause
Shen, Chao; Chen, Tao; Phan, Tai +6 more
During a one-hour interval of interplanetary magnetic field (IMF) Bz ≈ 0 nT, the equatorial spacecraft Double Star TC-1 encountered the dawn flank magnetopause many times at the magnetic local time (MLT) of about 08:00 and the latitude of about -27°. During each encounter, reconnection jets were observed with their velocities up to more…
Coronal partings
Dumin, Yurii V.; Nikulin, Igor F.
The basic observational properties of "coronal partings"-the special type of quasi-one-dimensional magnetic structures, identified by a comparison of the coronal X-ray and EUV images with solar magnetograms-are investigated. They represent the channels of opposite polarity inside the unipolar large-scale magnetic fields, formed by the rows of magn…
Development of a formalism for computing transits of Earth-directed CMEs, plasma sheaths, and shocks. Towards a forecasting tool
Corona-Romero, P.; Gonzalez-Esparza, J. A.
Interplanetary Coronal mass ejections (ICMEs) (super-magnetosonically) faster than the ambient solar wind are preceded by shock waves. Earth-directed shock waves, plasma sheaths and ICMEs are precursors of the major geomagnetic storms. The plasma sheath between the shock and the ICME leading edge plays a very important role to determine the geoeff…
Future dedicated Venus-SGG flight mission: Accuracy assessment and performance analysis
Zheng, Wei; Hsu, Houtse; Zhong, Min +1 more
This study concentrates principally on the systematic requirements analysis for the future dedicated Venus-SGG (spacecraft gravity gradiometry) flight mission in China in respect of the matching measurement accuracies of the spacecraft-based scientific instruments and the orbital parameters of the spacecraft. Firstly, we created and proved the sin…
First geodetic VLBI sessions with the Chinese Deep Space Stations Jiamusi and Kashi
Wang, Guangli; Xu, Dezhen; Dong, Guangliang +2 more
The first three 24-h S/X dual-band geodetic VLBI sessions using two new Chinese Deep Space Stations (CDSSs), Jiamusi and Kashi, and four Chinese VLBI Stations (CVSs), Beijing, Kunming, Seshan, and Urumqi were conducted with the goal of improving the two CDSSs' positions, which were previously known to a few decimeters. Due to the limited frequency…
Relationship between magnetic field properties and an X-class flare in active region NOAA 9077
Liu, D.; Liu, S.
The magnetic field plays a key role in producing solar flares, so that the investigation on the relationship between the magnetic field properties and flares is significant. In this paper, based on the magnetic field extrapolated from the photospheric vector magnetograms of the active region NOAA 9077 obtained at Huairou Solar Observing Station, t…
The end-of-life disposal of satellites in libration-point orbits using solar radiation pressure
Soldini, Stefania; Colombo, Camilla; Walker, Scott
This paper proposes an end-of-life propellant-free disposal strategy for libration-point orbits which uses solar radiation pressure to restrict the evolution of the spacecraft motion. The spacecraft is initially disposed into the unstable manifold leaving the libration-point orbit, before a reflective sun-pointing surface is deployed to enhance th…
The number distribution of weak Explosive Events observed by SUMER/SoHO
Mendoza-Torres, J. E.
Explosive Events (EEs) observed by SUMER on SoHO at the 1393.8 Å Si IV line are analyzed. We look for EEs to study their number distribution at low energies. Eight data sets taken in June 1996 in raster observations are used. In these observations a field on the solar disk is scanned several times during a period considerably longer than the typic…
Possible signature of solar oblateness in the Sun's oscillation frequency splittings
Woodard, M. F.
Departures from spherical symmetry split the frequencies of the Sun's normal oscillation modes. In addition to the well-studied, dominant splitting of the mode frequencies, due to the first-order advection of internal wave motion, a number of second-order effects of rotation on the frequency splittings, predominantly the solar oblateness, are expe…