Andres Galvez

Bio: Andres Galvez is an academic researcher from European Space Agency. The author has contributed to research in topics: Asteroid & Deflection (engineering). The author has an hindex of 7, co-authored 21 publications receiving 273 citations.

AIDA: The Asteroid Impact & Deflection Assessment Mission

Abstract: The Asteroid Impact and Deflection Assessment (AIDA) mission, a joint effort of ESA, JHU/APL, NASA, OCA, and DLR, is the first demonstration of asteroid deflection and assessment via kinetic impact. AIDA consists of two independent but mutually supporting mission elements, one of which is the asteroid kinetic impactor and the other is the characterization spacecraft. These two missions are, respectively, JHU/APL’s Double Asteroid Redirection Test (DART) and the European Space Agency’s Asteroid Investigation Mission (AIM) missions. As in the separate DART and AIM studies, the target of this mission is the binary asteroid [65803] Didymos in October, 2022. For a successful joint mission, one spacecraft, DART, would impact the secondary of the Didymos system while AIM would observe and measure any change in the relative orbit. AIM will be the first probe to characterise a binary asteroid, especially from the dynamical point of view, but also considering its interior and subsurface composition. The mission concept focuses on the monitoring aspects i.e., the capability to determine in-situ the key physical properties of a binary asteroid playing a role in the system’s dynamic behavior. DART will be the first ever space mission to deflect the trajectory of an asteroid in a measurable way.It is expected that the deflection can be measured as a change in the relative orbit period with a precision better than 10%. The joint AIDA mission will return vital data to determine the momentum transfer efficiency of the kinetic impact [1,2].

Learning to deflect near earth objects: industrial design of the don quijote mission

Abstract: Near-Earth Objects or NEOs include both objects having a likely asteroidal origin, and extinct comets orbiting the Sun in the near Earth Space, crossing the region of the inner planets. Because of their close approach to the Earth, NEOs are the population of the smallest Solar System bodies that can be accessible to detailed physical investigations, but in the same time they represent also a potential threat to our planet. Although impacts of large objects with catastrophic consequences are extremely infrequent, size of few tens or hundreds of meters in diameter can cause severe damage. A direct ground impact is not the sole threat since NEOs might be the origin to a large scale Tsunami whose consequences can exceed those of the Indian Ocean in 2004. The Don Quijote mission has been proposed by the European Space Agency as an asteroiddeflecting experiment with both a scientific and a practical perspective in the context of the management of the NEOs impact hazard. The primary objective of the DQ mission is to impact a given NEO with a spacecraft (Impactor) and to measure the resulting variations of the orbital parameters and of the rotation states by means of a second spacecraft (Orbiter) previously operating in the proximity of the asteroid. A radio science instrument carried by the Orbiter will be used for the precise measurement of the asteroid orbit and of its gravity field. The Orbiter will also perform measurements to determine the asteroid mass, size and surface properties. Secondary mission goals have also been defined, which would involve the deployment of an autonomous surface package and several other experiments and measurements. Three industrial teams have been awarded a contract by the European Space Agency to carry out phase-A studies in preparation for the detail design and development phases. This paper presents the main intermediate results of this design activity.

Forming a Moon with an Earth-like composition via a Giant Impact

Abstract: In the giant impact theory, the Moon formed from debris ejected into an Earth-orbiting disk by the collision of a large planet with the early Earth. Prior impact simulations predict that much of the disk material originates from the colliding planet. However, Earth and the Moon have essentially identical oxygen isotope compositions. This has been a challenge for the impact theory, because the impactor’s composition would have likely differed from that of Earth. We simulated impacts involving larger impactors than previously considered. We show that these can produce a disk with the same composition as the planet’s mantle, consistent with Earth-Moon compositional similarities. Such impacts require subsequent removal of angular momentum from the Earth-Moon system through a resonance with the Sun as recently proposed.

Absolute Magnitudes of Asteroids and a Revision of Asteroid Albedo Estimates from WISE Thermal Observations

Abstract: We obtained estimates of the Johnson V absolute magnitudes ( H ) and slope parameters ( G ) for 583 main-belt and near-Earth asteroids observed at Ondřejov and Table Mountain Observatory from 1978 to 2011. Uncertainties of the absolute magnitudes in our sample are H data with absolute magnitude values given in the MPCORB, Pisa AstDyS and JPL Horizons orbit catalogs. We found that while the catalog absolute magnitudes for large asteroids are relatively good on average, showing only little biases smaller than 0.1 mag, there is a systematic offset of the catalog values for smaller asteroids that becomes prominent in a range of H greater than ∼10 and is particularly big above H ∼ 12. The mean ( H catalog − H ) value is negative, i.e., the catalog H values are systematically too bright. This systematic negative offset of the catalog values reaches a maximum around H = 14 where the mean ( H catalog − H ) is −0.4 to −0.5. We found also smaller correlations of the offset of the catalog H values with taxonomic types and with lightcurve amplitude, up to ∼0.1 mag or less. We discuss a few possible observational causes for the observed correlations, but the reason for the large bias of the catalog absolute magnitudes peaking around H = 14 is unknown; we suspect that the problem lies in the magnitude estimates reported by asteroid surveys. With our photometric H and G data, we revised the preliminary WISE albedo estimates made by Masiero et al. ( Masired, J.R. et al. [2011] . Astrophys. J. 741, 68–89) and Mainzer et al. ( Mainzer, A. et al. [2011b] . Astrophys. J. 743, 156–172) for asteroids in our sample. We found that the mean geometric albedo of Tholen/Bus/DeMeo C/G/B/F/P/D types with sizes of 25–300 km is p V = 0.057 with the standard deviation (dispersion) of the sample of 0.013 and the mean albedo of S/A/L types with sizes 0.6–200 km is 0.197 with the standard deviation of the sample of 0.051. The standard errors of the mean albedos are 0.002 and 0.006, respectively; systematic observational or modeling errors can predominate over the quoted formal errors. There is apparent only a small, marginally significant difference of 0.031 ± 0.011 between the mean albedos of sub-samples of large and small (divided at diameter 25 km) S/A/L asteroids, with the smaller ones having a higher albedo. The difference will have to be confirmed and explained; we speculate that it may be either a real size dependence of surface properties of S type asteroids or a small size-dependent bias in the data (e.g., a bias towards higher albedos in the optically-selected sample of asteroids). A trend of the mean of the preliminary WISE albedo estimates increasing with asteroid size decreasing from D ∼ 30 down to ∼5 km (for S types) showed in Mainzer et al. ( Mainzer, A. et al. [2011a] . Astrophys. J. 741, 90–114) appears to be mainly due to the systematic bias in the MPCORB absolute magnitudes that progressively increases with H in the corresponding range H = 10–14.