Flight demonstration of new thruster and green propellant technology on the PRISMA satellite

The concept of a storable liquid monopropellant blend for space applications based on ammonium dinitramide (ADN) was invented in 1997, within a co-operation between the Swedish Space Corporation (SSC) and the Swedish Defense Research Agency (FOI). The objective was to develop a propellant which has higher performance and is safer than hydrazine. The work has been performed under contract from the Swedish National Space Board and ESA. The progress of the development has been presented in several papers since 2000.ECAPS, a subsidiary of the Swedish Space Corporation was established in 2000 with the aim to develop and market the novel “high performance green propellant” (HPGP) technology for space applications. The new technology is based on several innovations and patents w.r.t. propellant formulation and thruster design, including a high temperature resistant catalyst and thrust chamber.The first flight demonstration of the HPGP propulsion system will be performed on PRISMA. PRISMA is an international technology demonstration program with Swedish Space Corporation as the Prime Contractor.This paper describes the performance, characteristics, design and verification of the HPGP propulsion system for PRISMA. Compatibility issues related to using a new propellant with COTS components is also discussed. The PRISMA mission includes two satellites in LEO orbit were the focus is on rendezvous and formation flying. One of the satellites will act as a “target” and the main spacecraft performs rendezvous and formation flying maneuvers, where the ECAPS HPGP propulsion system will provide delta-V capability.The PRISMA CDR was held in January 2007. Integration of the flight propulsion system is about to be finalized.The flight opportunity on PRISMA represents a unique opportunity to demonstrate the HPGP propulsion system in space, and thus take a significant step towards its use in future space applications. The launch of PRISMA scheduled to 2009.     

Plasma irregularities in unstable outer ionosphere according to the Intercosmos-Bulgaria-1300 satellite data

The results of the satellite low-latitude and mid-latitude measurements of the disturbed plasma concentration, electron temperature, and quasi-stable electric field at heights of ～900 km after sunset are discussed. It is shown that the sharp fronts of changes in the electron temperature and plasma density observed in the experiment onboard the Intercosmos-Bulgaria-1300 satellite in the low-latitude (and equatorial) outer ionosphere can be related to damping of the oscillations of plasma electrons at local decreases of the plasma density (plasma “pits”) and formation of the vortex plasma structures at density and temperature gradients, which promotes conservation of ionosphere irregularities and makes the fronts of concentration variations steeper. Nonmonotonic variations in the plasma conductivity for the ionosphere currents in unstable plasma can be a cause of observed nonmonotonic disturbances of the vertical component of the “constant” electric field.     

US and Soviet planetary exploration The next step is Mars, together

Soviet General Secretary Gorbachev has proposed a joint US-Soviet programme to explore the planet Mars. The authors argue that there is considerable advantage to be gained from such a programme for both countries and for all nations on Earth. They trace the history of the US and Soviet space programmes and of cooperation between the two nations, focusing particularly on activities relating to Mars. Robotic Mars exploration is already technically possible and could take place in the 1990s, and a first step towards manned exploration could be the writing of a development and flight plan aiming for the first decade of the 21st century.     

Quasiperiodic oscillations of the sub-mHz band in near-sun plasma according to the coherent radio occultation data

In 2013 and 2015, investigations of the internal solar wind were carried out using the method of two-frequency radio sounding by signals from the Mars Express European spacecraft. The values of the S- and X-bands’ frequency and the differential frequency were registered with a sampling rate of 1s at the American and European networks of ground-based tracking stations. The spatial distribution of the frequency fluctuation’s level has been studied. It has been shown that the intensity of frequency fluctuation considerably decreases at high heliolatitudes. In some radio sounding sessions, quasiperiodic oscillations of sub-mHz band have been observed in the temporal spectra of frequency fluctuations; they are supposed to be associated with the density inhomogeneities, the sizes of which are close to the turbulence outer scale.     

The Far Ultra-Violet Imager on the Icon Mission

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N₂ ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of \(\mathrm{O}^{+}\) ions used to compute the nighttime ionospheric altitude distribution. ICON Far UltraViolet (FUV) imager is a Czerny–Turner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to overcome the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft.     

Observation of Terrestrial gamma-ray flashes in the RELEC space experiment on the <Emphasis Type="Italic">Vernov</Emphasis> satellite

The RELEС scientific payload of the Vernov satellite launched on July 8, 2014 includes the DRGE spectrometer of gamma-rays and electrons. This instrument comprises a set of scintillator phoswich-detectors, including four identical X-ray and gamma-ray detector with an energy range of 10 kev to 3 MeV with a total area of ~500 cm² directed to the atmosphere, as well as an electron spectrometer containing three mutually orthogonal detector units with a geometric factor of ~2 cm² sr. The aim of a space experiment with the DRGE instrument is the study of fast phenomena, in particular Terrestrial gamma-ray flashes (TGF) and magnetospheric electron precipitation. In this regard, the instrument provides the transmission of both monitoring data with a time resolution of 1 s, and data in the event-by-event mode, with a recording of the time of detection of each gamma quantum or electron to an accuracy of ~15 μs. This makes it possible to not only conduct a detailed analysis of the variability in the gamma-ray range, but also compare the time profiles with the results of measurements with other RELEC instruments (the detector of optical and ultraviolet flares, radio-frequency and low-frequency analyzers of electromagnetic field parameters), as well as with the data of ground-based facility for thunderstorm activity. This paper presents the first catalog of Terrestrial gamma-ray flashes. The criterion for selecting flashes required in order to detect no less than 5 hard quanta in 1 ms by at least two independent detectors. The TGFs included in the catalog have a typical duration of ~400 μs, during which 10–40 gamma-ray quanta were detected. The time profiles, spectral parameters, and geographic position, as well as a result of a comparison with the output data of other Vernov instruments, are presented for each of candidates. The candidate for Terrestrial gamma-ray flashes detected in the near-polar region over Antarctica is discussed.     

Designing corrections for the trajectory of the <Emphasis Type="Italic">Spektr-R</Emphasis> spacecraft in the event of immersions into the Moon’s sphere of influence

The results of updating the parameters of motion of the Spektr-R spacecraft at the end of 2016 have shown that, in January 2018, with a probability close to unity, the condition that a spacecraft stay in the Earth’s shadow is violated; however, in May of the same year, the ballistic life of the spacecraft will be terminated. Thus, in 2017, the question arose of how to design the correction of flight of this spacecraft using its onboard propulsion system. The correction was designed with allowance for the fact that, for the first time since it was launched, the spacecraft in the course of several years, beginning with 2017, repeatedly approaches the Moon, deeply immersing into its sphere of influence. This paper presents the technologically and organizationally convenient, allowable versions of upcoming correction of the Spektr-R spacecraft trajectory and justifies the particular scheme of its implementation.     

Study of the magnetospheres of active regions on the sun by radio astronomy techniques

In the 1990s, based on detailed studies of the structure of active regions (AR), the concept of the magnetosphere of the active region was proposed. This includes almost all known structures presented in the active region, ranging from the radio granulation up to noise storms, the radiation of which manifests on the radio waves. The magnetosphere concept, which, from a common point of view, considers the manifestations of the radio emission of the active region as a single active complex, allows one to shed light on the relation between stable and active processes and their interrelations. It is especially important to identify the basic ways of transforming nonthermal energy into thermal energy. A dominant role in all processes is attributed to the magnetic field, the measurement of which on the coronal levels can be performed by radio-astronomical techniques. The extension of the wavelength range and the introduction of new tools and advanced modeling capabilities makes it possible to analyze the physical properties of plasma structures in the AR magnetosphere and to evaluate the coronal magnetic fields at the levels of the chromosphere–corona transition zone and the lower corona. The features and characteristics of the transition region from the S component to the B component have been estimated.     

High-Energy Electron Beam Relaxation in a Stationary Plasma Thruster

In the paper, processes of high-energy electron beam interaction with plasma particles in a discharge channel of a stationary plasma thruster are analyzed and the results are presented.     

Hardware reconfiguration algorithm in multiprocessor systems of integrated modular avionics

Reconfiguration of multiprocessor systems makes it possible to improve their failure-resistance that is especially important for the integrated modular avionics systems. The algorithm considered in this paper allows minimizing the reservation and providing the better safety level and more effective flight completion or even its further execution in the case of failures of airborne equipment.