urn:nasa:pds:context:instrument:rss.orex 1.0 1.16.0.0 Product_Context 2021-09-10 1.0 First version of the context product to be archived with the PDS. urn:nasa:pds:context:instrument_host:spacecraft.orex instrument_to_instrument_host 10.1007/s11214-018-0521-6 E.B. Bierhaus, B.C. Clark, J.W. Harris, K.S. Payne, R.D. Dubisher, D.W. Wurts, R.A. Hund, R.M. Kuhns, T.M. Linn, J.L. Wood, A.J. May, J.P. Dworkin, E. Beshore, D.S. Lauretta and the OSIRIS-REx Team, The OSIRIS-REx Touch-and-Go Sample Acquisition Mechanism (TAGSAM) and Flight System, Space Science Reviews, 214:107, 2018. This paper describes the OSIRIS-REx spacecraft and its main subsystems. The paragraph on telecommunications gives high-level information on the radio, including data downlink strategy and data rates. 10.1007/s11214-018-0480-y McMahon, J.W., Scheeres, D.J., Hesar, S.G., Farnocchia, D., Chesley, S., Lauretta, D. The OSIRIS-REx Radio Science Experiment at Bennu. Space Sci Rev 214, 43 (2018). This paper describes the originally planned OSIRIS-REx Radio Science investigation of the asteroid Bennu with a primary goal of estimating the mass and gravity field of the asteroid. There is very little discussion of the spacecraft radio instrumentation in the paper.The spacecraft conducted proximity operations around Bennu for over 1 year, during which time radiometric tracking data, optical landmark tracking images, and altimetry data were obtained that could be used to make these estimates. The Radio Science team was also responsible for estimating the surface accelerations, surface slopes, constraints on the internal density distribution of Bennu, the rotational state of Bennu to confirm YORP estimates, and the ephemeris of Bennu that incorporates a detailed model of the Yarkovsky effect. 10.1126/sciadv.abc3350 D. J. Scheeres, A. S. French, P. Tricarico, S. R. Chesley, Y. Takahashi, D. Farnocchia, J. W. McMahon, D. N. Brack, A. B. Davis, R.-L. Ballouz, E. R. Jawin, B. Rozitis, J. P. Emery, A. J. Ryan, R. S. Park, B. P. Rush, N. Mastrodemos, B. M. Kennedy, J. Bellerose, D. P. Lubey, D. Velez, A. T. Vaughan, J. M. Leonard, J. Geeraert, B. Page, P. Antreasian, E. Mazarico, K. Getzandanner, D. Rowlands, M. C. Moreau,J. Small, D. E. Highsmith, S. Goossens, E. E. Palmer, J. R. Weirich, R. W. Gaskell, O. S. Barnouin, M. G. Daly, J. A. Seabrook, M. M. Al Asad, L. C. Philpott, C. L. Johnson, C. M. Hartzell, V. E. Hamilton, P. Michel, K. J. Walsh, M. C. Nolan, D. S. Lauretta; Heterogeneous mass distribution of the rubble-pile asteroid (101955) Bennu. Science Advances, doi:10.1126/sciadv.abc3350, 2020. The asteroid (101955) Bennu has a heterogeneous internal mass distribution with an underdense center and equatorial bulge. The gravity field of a small body provides insight into its internal mass distribution. We used two approaches to measure the gravity field of the rubble-pile asteroid (101955) Bennu: (i) tracking and modeling the spacecraft in orbit about the asteroid and (ii) tracking and modeling pebble-sized particles naturally ejected from Bennu’s surface into sustained orbits. These approaches yield statistically consistent results up to degree and order 3, with the particle-based field being statistically significant up to degree and order 9. Comparisons with a constant-density shape model show that Bennu has a heterogeneous mass distribution. These deviations can be modeled with lower densities at Bennu’s equatorial bulge and center. The lower-density equator is consistent with recent migration and redistribution of material. The lower-density center is consistent with a past period of rapid rotation, either from a previous Yarkovsky-O’Keefe-Radzievskii-Paddack cycle or arising during Bennu’s accretion following the disruption of its parent body. 10.1029/2019JE006363 S. R. Chesley, A. S. French, A. B. Davis, R. A. Jacobson, M. Brozović, D. Farnocchia, S. Selznick, A. J. Liounis, C. W. Hergenrother, M. C. Moreau, J. Pelgrift, E. Lessac-Chenen, J. L. Molaro, R. S. Park, B. Rozitis, D. J. Scheeres, Y. Takahashi, D. Vokrouhlický, C. W. V. Wolner, C. Adam, B. J. Bos, E. J. Christensen, J. P. Emery, J. M. Leonard, J. W. McMahon, M. C. Nolan, F. C. Shelly, D. S. Lauretta, Trajectory Estimation for Particles Observed in the Vicinity of (101955) Bennu, JGR Planets, https://doi.org/10.1029/2019JE006363, 2020. The Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) mission discovered that near-Earth asteroid (101955) Bennu is periodically ejecting small particles from its surface, placing it in the uncommon class of “active asteroids.” We linked together individual detections of ejected particles and used numerical models of the forces acting on them to ascertain their trajectories and fates. We found that most particles have suborbital trajectories, meaning they fall back to Bennu's surface shortly after being ejected, but some orbit Bennu for days at a time, and some escape directly into space. From the particle trajectories, we are able to estimate their sizes (comparable to pebbles, from a few millimeters to a few centimeters in diameter) and shapes (probably flake like). Their trajectories also make it possible to estimate Bennu's gravity field more precisely than spacecraft measurements and help shed light on the possible causes of the ejections. Radio Science (Telecom) Subsystem Radio Science not applicable not applicable The spacecraft element of the OSIRIS-REx radio science instrument was the onboard telecommunications subsystem. It included a pair of cross-strapped redundant General Dynamics Small Deep Space Transponder Group Buy III X/X transponders, two cross-strapped 100-watt traveling wave tube amplifiers, and four antennas. Cross-strapping protected the mission against single point failures in the telecom subsystem. The antenna location in reference to the s/c frame are defined as follows: - the HGA frame is nominally rotated from the s/c frame by +90 degrees about Y, then by -150 about Z. - the MGA frame is nominally rotated from the s/c frame by +106 degrees about Y. - the LGA_PX frame is nominally rotated from the s/c frame by +135 degrees about Y. - the LGA_MX frame is nominally rotated from the s/c frame by -45 degrees about Y. Turnaround Ratio – 840/749 Nominal uplink and downlink frequencies – Nominal Rx Freq – 7188.499990 MHz, Nominal Tx Freq – 8445.767679 MHz The transponder carrier delay variation is +/- 3 ns The radio science investigation used all available data over the course of the mission.