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The miniRAD radiometer is one of the payloads of the Idefix rover on the MMX mission to Phobos. It is a multispectral instrument which measures the infrared radiative flux in six wavelength channels between 4.7 and 100 µm using single-element thermopile detectors. MiniRAD is equipped with optical filters, one centered at 5.5 µm, three narrow bandpass filters at 8.3 µm, 8.9 µm, and 9.5 µm and two longpass filters with cut-ons at 14–15 µm. One of the longpass filters made from boron nitride (BN) is especially optimized for very low flux, being sensitive in the very long wavelength region even beyond 50 µm. The main measurement objective of the miniRAD instrument is the determination of Phobos’ surface brightness temperature during nighttime, from which the thermal inertia of the surface can be derived. Secondary objectives are to provide constraints on the slope of the emissivity in the thermal infrared, the location of the Christiansen feature, and the surface roughness of Phobos. MiniRAD has been calibrated radiometrically under relevant environmental conditions using a cavity blackbody over the full expected range of object temperatures from 100 to 330 K. The predicted uncertainty of the brightness temperature is < 1 K at dayside temperatures > 270 K for all channels, while the BN filter uncertainty is < 5 K at the lowest calibration temperature of 100 K.

IDEFIX, a rover to be delivered to the martian moon Phobos, is part of the Martian Moons eXploration (MMX) mission by the Japan Aerospace Exploration Agency, JAXA. MMX will explore both moons of Mars remotely but will also land on Phobos and collect samples from its surface and return them back to Earth. The IDEFIX rover will be released from the main spacecraft during its landing rehearsal at an altitude of about 40 m. It will fall to the surface, probably bounce several times and upright itself after having come to rest by applying an autonomous sequence of the deployment of its locomotion system. This sequence is followed by deployment of the solar generator and recharging of the batteries. After commissioning, on-Phobos operations are planned for at least 100 (Earth-) days. Sequences of science operations (instrument measurements), driving, battery charging and communications with Earth (via the main spacecraft) will alternate in a way to maximize scientific return and fulfill technical demonstration goals. IDEFIX accommodates a payload of four scientific instruments: a Raman spectrometer (RAX), a stereo pair of cameras looking forwards (NavCams; also used for navigation), a radiometer (miniRAD), and two cameras looking at the wheel-surface interface (WheelCams). MMX will be launched in autumn 2026, the Rover delivery to Phobos is currently planned for late 2028, before the first touch down of the spacecraft and sample collection. The Rover is a contribution by the Centre National d’Etudes Spatiales (CNES) and the German Aerospace Center (DLR) with additional contributions from INTA (Spain) and JAXA (Japan).

The transposon theory of aging hypothesizes the activation of transposable elements (TEs) in somatic tissues with age, leading to a shortening of the lifespan. It is thought that TE activation in aging produces an increase in DNA double-strand breaks, contributing to genome instability and promoting the activation of inflammatory responses. To investigate how TE regulation changes in somatic tissues during aging, we analyzed the expression of some TEs, as well as a source of small RNAs that specifically silence the analyzed TEs; the Drosophila cluster named flamenco. We found significant variations in the expression levels of all the analyzed TEs during aging, with a trend toward reduction in middle-aged adults and reactivation in older individuals that suggests dynamic regulation during the lifespan.

Enhancers can function over great distances and interact with almost any kind of promoter, but insulators or promoter competition generally limit their effect to a single gene. We provide in vivo evidence that retroelements may establish promoter competition with their neighboring genes and restrict the range of action of an enhancer. We report that the retroelement Idefix from Drosophila melanogaster inhibits white gene expression in testes by a promoter competition mechanism that does not occur in the eyes. The sequence specificity of the two TATA‐less promoters of white and Idefix is a prime determinant in the competition that takes place in tissues where both are transcriptionally active. This study brings to light a novel mechanism whereby transcriptional interference by an active retrotransposon may perturb expression of neighboring genes. This capacity to interfere with the transcriptional regulation of their host, together with the facts that retroelements preferentially move within the germline and do not excise to replicate, suggest that these elements are cis ‐regulatory sequences able to imprint specific and heritable controls essential for eukaryotic gene regulation.

We describe a novel transposition system in a line of Drosophila melanogaster called RevI in which two retroelements are mobilized. These elements are the retroelement ZAM, recently described in the literature, and a novel element designated Idefix. Like ZAM, Idefix displays the structural features of a vertebrate retrovirus. Its three open reading frames encode predicted products resembling the products of the gag, pol, and env genes of retroviruses. In situ hybridization and Southern analyses performed on the RevI genome revealed the presence of some 20 copies of ZAM and Idefix, whereas ZAM is absent and Idefix is present in only four copies on the chromosomal arms of the original parental line. From RevI, a series of mutations affecting eye coloration has been recovered. The genetic and molecular analyses of these mutations have shown that most of them affected the white locus through three rounds of mutational events. The first mutational event was previously shown to be caused by a ZAM insertion 3 kb upstream of the transcription start site of white. It confers a red-brick phenotype to the orange eye coloration of the parental line. The second event results from the insertion of an Idefix copy 1.7 kb upstream of the transcription start site of the white gene, which modifies the red-brick phenotype to orange. This second mutational event was recovered as a recurrent specific mutation in 11 independent individuals. The third event results from an additional Idefix located 1.7 kb upstream of white that is responsible for the full reversion of the orange phenotype to red-brick. The fact that such mutations due to recurrent appearances of both ZAM and Idefix at the white locus result in such a variety of phenotypes brings to light a new molecular system in which the interference of mobile elements with the correct expression of the host gene can be tested.

Transposable elements represent a large fraction of eukaryotic genomes and they are thought to play an important role in chromatin structure. ZAM and Idefix are two LTR-retrotransposons from Drosophila melanogaster very similar in structure to vertebrate retroviruses. In all the strains where their distribution has been studied, ZAM appears to be present exclusively in the intercalary heterochromatin while Idefix copies are mainly found in the centromeric heterochromatin with very few copies in euchromatin. Their distribution varies in a specific strain called RevI in which the mobilization of ZAM and Idefix is highly induced. In this strain, 15 copies of ZAM and 30 copies of Idefix are found on the chromosomal arms in addition to their usual distribution. Amongst the loci where new copies are detected, a hotspot for their insertion has been detected at the white locus where up to four elements occurred within a 3-kb fragment at the 5' end of this gene. This property of ZAM and Idefix to accumulate at a defined site provides an interesting paradigm to bring insight into the effect exerted by multiple insertions of transposable elements at an euchromatic locus.