“LICIACube – the Light Italian Cubesat for Imaging of Asteroids” is managed by the Italian Space Agency (ASI) and will be part of the NASA DART mission, with the aim of i) documenting the DART ...impact’s effects on the secondary member of the (65803) Didymos binary asteroid system, ii) characterizing the shape of the target, and iii) performing dedicated scientific investigations on it. DART probe will be launched at the end of 2021 and LICIACube will be hosted as piggyback during the interplanetary cruise, then released 10 days before the impact, and autonomously guided along its fly-by trajectory. The LICIACube payload is composed by LEIA, a narrow FoV camera, and LUKE, a wide FoV imager with an RGB Bayer pattern filter, that will collect and transmit to Earth several unique images of the effects of the DART impact on the asteroid, such as the formation and the development of the plume potentially determined by the impact.
LICIACube will be the first deep space mission developed and autonomously managed by an Italian team: the design, integration and test of the CubeSat have been assigned by ASI to the aerospace company Argotec, while the LICIACube Ground Segment has a complex architecture based on the Argotec Mission Control Center, antennas of the NASA Deep Space Network and data archiving and processing, managed at the ASI Space Science Data Center. The LICIACube team includes a wide Italian scientific community, involved in the definition of all the aspects of the mission: trajectory design; mission definition (and real-time orbit determination during operations); impact, plume and imaging simulation and modelling, in preparation of a suitable framework for the analysis and interpretation of in-situ data. The major technological mission challenge, i.e. the autonomous targeting and imaging of such a small body during a fast fly-by, to be accomplished with the limited resources of a CubeSat, is affordable thanks to a strong synergy of all the mentioned teams in support of the engineering tasks.
-LICIACube is the first purely Italian spacecraft operating in deep space.-LICIACube is managed by the Italian Space Agency and will be part of the NASA DART mission.-It will analyze the output of the first kinetic impact test at a realistic scale.-The payload is composed by LEIA, a narrow FoV camera, and LUKE, a wide FoV imager with an RGB Bayer pattern filter.-Aims: documenting the DART impact on Dimorphos; characterizing the target shape; performing scientific investigations.
The Engineering Radiation Monitor measures dose, dose rate, and charging currents on the Van Allen Probes mission to study the dynamics of Earth's Van Allen radiation belts. Over 5 years, results ...from this monitor show a variation in dose rates with time, a correlation between the dosimeter and charging current data, and a comparison of cumulative dose to prelaunch modeling. Solar cell degradation monitor patches track the decrease in solar array output as displacement damage accumulates. The Solar Cell Monitor shows ~33% cumulative degradation in maximum power after 5.1 years of the mission. The desire to extend the mission to ~2,500 days from 800 days created increased requirements for the ionizing radiation hardness of spacecraft and science instrument electronics. We describe the investigations that insured compliance with these enhanced requirements.
Key Points
The Engineering Radiation Monitor dose and dose rate data versus time and shield depth are summarized
The Solar Cell Monitor shows ~33% cumulative degradation in maximum power after 5.1 years of the mission
The observatories electronic parts were qualified for a ~800‐day mission; a radiation hardness survey gives a projection exceeding the 2,500‐day extended mission goal
Proteins associated with 36S virus RNA from Vero cells infected with San Miguel sea lion virus, type 2 (SMSV-2), were labelled with 125I. One protein, VPg, remained linked to RNA when subjected to ...deproteinization techniques. VPg labelled wtih 32P was observed on 36S RNA from purified virions; the quantity of label was compatible with two phosphates per genome. The estimated mol. wt. of SMSV-2 VPg was 15 000.
Platelet factor 4 (heparin neutralizing) activity shortens the thrombin time of a heparinized plasma. In the proposed procedure (I) a heparin thrombin time curve is constructed by adding gradually ...increasing amounts of heparin to a commercial plasma substrate and determining thrombin times, (2) a suitable concentration of heparin that gives highest reproducible thrombin time is selected and added to the substrate, (3) thrombin times are determined for the heparinized substrate before and after addition of a test material containing platelet factor 4. The two thrombin times are converted to heparin concentration by reference to the heparin thrombin time curve. The difference in heparin concentrations represents platelet factor 4 activity. When lyophilized commercial plasma is used as substrate larger quantities of heparin can be employed in the system, resulting in improved sensitivity and precision.
An improved micromethod for plasma fibrinogen, based on the Ellis-Stransky thrombin-clot density procedure, is presented. Modifications includes: (1) addition of Polybrene eliminates heparin ...interference; (2) measurement of absorbance at 340 nm provides improved sensitivity at low fibrinogen levels as well as with small volumes of plasma (40 mul.); (3) higher concentration of thrombin reduces the incubation time. Plasma fibrinogen by the proposed method compares well with a reference procedure based on total clottable protein (coefficient of correlation 0.99).
Three plasma fibrinogen methods are presented based on (1) clottable protein assay by Biuret reagent, (2) measurement of clot absorbance and (3) thrombin time. These methods show good correlation and ...adequate precision on normal subjects as well as heparinized plasmas. The effects of interference owing to hemolysis, lipemia, bilirubin, heparin and fibrinogen degradation products are discussed briefly.
Methods for plasma fibrinogen based on thrombin time are technically simple, rapid, and sensitive, although "false low" results may occur due to heparin interference. The present modification ...incorporates Polybrene into buffer to eliminate this heparin interference. The proposed method shown excellent agreement with a reference procedure based on clottable protein, and excellent day-to-day precision (C.V.3.5%). The present method is easily adaptable to semi-automated measurements.
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