Rosetta at Comet 67P/Churyumov- Gerasimenko: Landing and Archiving Data NASA SBAG Report

Bonnie Buratti, US Rosetta Project Scientist, JPL Arthur B. Chmielewski US Rosetta Project Manager, JPL 1 Mathieu Choukroun, US RosettaDeputy Project Scientist, JPL

January 11, 2017 Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI.

The US Contribution to Rosetta 1. 3 ½ instruments 2. 3 PI’s, PS, DPS, IDS 3. 46 Co-I’s and researchers 4. DSN 70 m and 34 m support 5. ASPEN scheduling software for science observations 6. SPICE support 7. Comet modeling 8. Shadow navigation for flight dynamics verification 9. Outreach and media products 2 10. Leadership for ESA's Amateur Ground Observing Campaign

Instrument Purpose Country of Origin Alice Ultraviolet spectrometer United States CONSERT Radar tomography France COSIMA Dust composition Germany GIADA Dust detector Italy MIDAS Atomic Force Microscope Austria MIRO Microwave spectrometer/radiometer United States OSIRIS Narrow-angle and wide-angle cameras Germany 3 ROSINA Gas composition Switzerland RPC Magnetometer, plasma detectors Various, inc. US RSI Radio science investigation Germany VIRTIS Infrared spectrometer Italy Rosetta.jpl.nasa.gov Escorting the comet

Sept 2016 – Landing!

August 2014

4

Credit: NASA/JPL Caltech National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Outreach activities late 2016

• Claudia Alexander was a tireless proponent of outreach, and we have tried to continue on that path • Public lecture (von Karman series) on August 11 and 12 by Project Manager and Project Scientist; 600 participants plus thousands of streaming viewers • An Educators’ Workshop at JPL was held on Sept. 24, 2016 with about 40 teachers attending. The full day event included lectures on small bodies and Rosetta, plus hands-on activities such as “kitchen comets”. • Partnership with Chinle (Arizona) school district for month-long science program in June; 20-30 students from Navajo Nation participate • Sept. 30: Friends & Family program prior to “landing” leading into NASA TV live from Darmstadt and into ESA feed. Don Yeomans was M. C. • Popular NASA Rosetta Blog written by co-Is • NASA TV and interview events associated with landing on Sept. 30, 2016 • Outreach events planned for the Science Working Team Meeting #47 in New York City, reaching an underserved cohort

Ekaterina Smirnova prox Space Artist

Ekaterina Smirnova, Rosetta’s artist, presented a show on Rosetta during DPS, gave a talk at JPL on Oct. 24, and is invited to talk in New York. 6 National Aeronautics and Space Administration Jet Propulsion Laboratory U.S. Rosetta Project California Institute of Technology JPL/Caltech Proprietary – Not for Public Release Philae found Sept 5, 2016

7 National Aeronautics and Space Administration Jet Propulsion Laboratory U.S. Rosetta Project California Institute of Technology JPL/Caltech Proprietary – Not for Public Release Rosetta End-of-Mission: Landing on 67P

• Targeted impact region just beside one large pit of the Ma’at region. • Most instruments “ON” until the end.

Impact site Ma’at pit “D”

8 Sept 5, 2016 Sept 2, 2016

Approx. FOV: 171 M 157 M

Check out: https://planetgate.mps.mpg.de/Image_of_the_Day/public/IofD_archive.html 9 National Aeronautics and Space Administration Jet Propulsion Laboratory U.S. Rosetta Project California Institute of Technology JPL/Caltech Proprietary – Not for Public Release Final images before landing: 5.8 km and ~ 25 meters

FOV 223 m FOV 96 cm 10 National Aeronautics and Space Administration Jet Propulsion Laboratory Last data from NASA U.S. Rosetta Project California Institute of Technology JPL/Caltech Proprietary – Not for Public Release Instruments on Rosetta

Rosetta’s descent provided a wealth of high-resolution data, which will be invaluable to understand the influence of small-scale features on the surface of 67P on the data obtained by MIRO and Alice.

MIRO: last 1 h of subsurface temperature Alice: last UV spectrum 8 min before impact

Courtesy: F. Peter Schloerb

Data packet obtained in last 1 minute before impact Shaded cliff of Ma’at pit D

Courtesy: Joel Parker

11 Top 10 discoveries of Rosetta (with US contributions)

1. Comet 67P/ Churyumov-Gerasimenko is primitive and relatively unprocessed, except in its very shallow subsurface (upper few meters). Partly MIRO (Microwave Imager for Rosetta), built at JPL. 2. Molecular hydrogen, oxygen, and nitrogen were discovered, and they were incorporated at the comet from the beginning, showing that the comet formed in a low-temperature environment. US co-Is on ROSINA, the Rosetta Mass Spectrometer 3. The ratio of deuterium to hydrogen in the water from the comet was determined to be three times that found for terrestrial water, showing that the D/H ratio in water from Jupiter-Family comets vary widely. This suggests possible multiple reservoirs, or a more complex D/H distribution in the solar nebula than previously thought. US co-Is on ROSINA. 4. The nucleus is far more complicated than envisioned: the comet is nearly binary, composed of two planetesimals. There are pits (former outgassing sites), cliffs, layers, “goose bumps”, “dinosaur eggs”, and boulders. The comet’s jets originate mostly from cliffs and pit walls. One Imaging Team Member (Bjorn Davidsson) now at JPL. 5. The density of the comet is low, about 0.5 gm/cc. The upper ~20 cm is tenuous, covering a harder, more compact layer. Further into the comet, the density decreases. (MIRO data and partly DSN data; US IDS Weissman on Radio Science Team) 6. The comet’s nucleus has no magnetic field. US co-Is on Magnetometer team. 7. Most of the outgassing of water takes place at the neck region because of shape and orientation (MIRO). 8. Organic molecules, including the amino acid glycine, were detected on the comet. . US co-Is on ROSINA. 9. Diamagnetic cavities were found in the vicinity of the comet (Electrons detected by the Ion Electron Spectrometer from SWRI helped map them; US co-Is on Magnetometer team).

10. Electrons, rather than solar photons, are responsible for the rapid breakup of water and CO2 (Alice – UV spectrometer built at SWRI - discovery) 11. (Bonus) The comet is dusty, with a dust to gas ratio of ~4:1 near perihelion

Comet 67P/ Churyumov-Gerasimenko in context: Characterizing both comets and Kuiper Belt Objects (KBOs) 67/P Primitive Smallest KBO observed 3.1 km radius Wild-2 (Stardust) ?

Tempel-1 2104 MU 69 (Deep Impact) New Horizons KBO target 2019 ~45 km radius Phoebe Pluto (this is Pandora) Cassini flyby Charon New Horizons Captured KBO New Horizons Largest known KBO Battered, dense (1.6 gm/cc) Global melting Differentiated Undifferentiated Differentiated (?) Active geology 606 km radius Comets above 107 km radius 1187 km radius

KBOs (increasing size) National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Rosetta Data Analysis Program (RDAP)

• The intent of the Rosetta Data Analysis Program is to provide the funding that will allow for continued analysis and interpretation of data, provide the opportunity for new collaborations and investigators, and support limited laboratory and field measurements (including astronomical data) to interpret space measurements correctly. Synergistic analyses will be encouraged, including comparisons with data from other missions • Can propose analysis of PDS data that is available at time of issue • Typically $100-200K/year/3 years award levels • Collaborations with European PIs encouraged (no funding to international investigations) • Headquarters assurance that RDAP will occur

Recent and upcoming significant events

• AGU Fall Meeting 2016 special session: 8 oral talks and 22 poster talks • US co-I meeting at AGU Dec. 11: over 30 participants and talks • US Rosetta Scientific Working Team (SWT #47) meeting in the US in 2017 – first ever. Location is New York City, March 14-17, 2017 • March 2017 co-I meeting will be combined with SWT #47 • Archiving into PDS and ESA’s Planetary Science Archive (PSA) proceeding on schedule. Level 3 and 4 products are being emphasized. Some concern as end-of-Project for NASA is March 31, 2018, while ESA will continue until the end of 2019. Delta-review in early 2018 may be required.

15 The US Rosetta Project would like to thank:

• ESA for the fabulous ride • NASA HQ - Jim Green, Tony Carro and David Schurr for steadfast support over the years