C. Raymond SBAG12 06 Jan 2015

Slide 1

Dawn Status Report

Small Bodies Assessment Group C. Raymond, JPL

06 Jan 2015 Tempe, AZ

C. Raymond SBAG12 06 Jan 2015

Slide 2

Mission Status

Flight Team is performing well and the Flight System is healthy

• The spacecraft is thrusting nominally on approach to Ceres • Estimated Ceres arrival (capture) date is 6 March 2015 • First science orbit begins April 22 (RC3)

Instruments are all healthy and performing well

• Performed framing camera straylight calibration to resolve remaining contamination

• VIR inflight calibration of the IR channel has (finally) yielded a good calibration for this spectral range – calibration will be published and archived in near future

Team is awaiting the selection of Guest Investigators

C. Raymond SBAG12 06 Jan 2015

Slide 3

Recent Highlights

• Dawn experienced a safing event on September 11 – Altered the Approach geometry – Delayed the beginning of science acquisition ~1 month – Causes of the problem are well understood and are not a risk for

future operations

• Ceres plans are set – Resource margins are robust to the planned 16-month primary

mission – If the reaction wheels perform well the spacecraft could last until

late in 2016 – Observations aimed at detecting water vapor have been

incorporated into the plan (high phase and limbs)

• Vesta data analysis/mapping nearly complete

C. Raymond SBAG12 06 Jan 2015

Slide 4

Vesta Data Analysis • Special Issue of Icarus on Geologic Mapping of Vesta

– Global and Quadrangle Maps based on entire data set

• Special Issue in prep on Compositional Mapping (Icarus)

C. Raymond SBAG12 06 Jan 2015

Slide 5

Gullies on Vesta: Evidence of Flowing Water

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• Recent large craters in the area near Marcia crater show evidence of sinuous intersecting gullies in the crater walls

• Consistent with release of water from the crust upon impact • Material flowed into the bottom of Marcia crater and escaping water

left pits in the crater floor

Scully et al., Icarus, 2015

C. Raymond SBAG12 06 Jan 2015

Slide 6

Ceres Hydrazine Usage Estimate

Uncertainty = ± 3. kg

Margin = 2.5 kg

Contingency = 3.2 kg

CBE = 16.3 kg

C. Raymond SBAG12 06 Jan 2015

Slide 7

Ceres Late Approach and Capture

RC 3

RC 2

Capture

This was the plan prior to Sep 2014 safing

C. Raymond SBAG12 06 Jan 2015

Slide 8

eres Approach

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Approach Trajectory

Sun

Capture (March 6)

1st science orbit (Rotation Characterization #3)

Ceres Approach

View from Above

Tick marks every 2 days

Capture

Sun

Tick marks every day

Current Plan

C. Raymond SBAG12 06 Jan 2015

Slide 9

Ceres – Our First Peek

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Taken Dec 1, 2014 at a distance of 1.2 million km, about 3 times the Earth-Moon distance

Framing Camera Straylight Test

C. Raymond SBAG12 06 Jan 2015

Slide 10

Ceres Approach Timeline Date Activity Distance Pixels Comment

Dec 1, 2014 Calibration image of Ceres 1.12M km 8 Complete

Jan 13, 2015 First OpNav Image of Ceres 379,000 km 26 0.8x Hubble resolution

Jan 26, 2015 OpNav #2 201,000 km 43 1.4x Hubble resolution

Feb 4, 2015 OpNav #3 148,000 km 68 2.2x Hubble resolution

Feb 12, 2015 Rotation Characterization #1 84,000 km 116 3.7x Hubble resolution

Feb 20, 2015 Rotation Characterization #2 48,000 km 226 7x Hubble resolution

Feb 23, 2015 Closest Approach Begin high-phase Approach

Feb 25, 2015 OpNav #4 39,000 km 264 8x Hubble resolution

Mar 2, 2015 OpNav #5 50,000 km 205 6.5x Hubble resolution

Mar 6, 2015 Capture Capture into orbit

Apr 10, 2015 OpNav #6 33,000 km 300 9.5x Hubble resolution

Apr 15, 2015 OpNav #7 21,000 km 470 15x Hubble resolution

Apr 23, 2015 Rotation Characterization #3 13,000 km 20x Hubble resolution

C. Raymond SBAG12 06 Jan 2015

Slide 11

Ceres Approach Geometry

C. Raymond SBAG12 06 Jan 2015

Slide 12

Ceres Science Orbits • 406 days of operations are planned at Ceres

– Primarily constrained by hydrazine • RC3

– Phase angle = varying – Duration 1 orbit (20 days) – Nadir rotation movies, high phase observations.

• Survey Orbit: – Beta angle = 10-25º drifting, Incl. = 90º – Duration 7 orbits (22 days) – Nadir mapping, limb observations

• High Altitude Mapping Orbit (HAMO): – Beta angle = 27-37º drifting, Incl. = 90º – Duration 70 orbits (56 days) – Nadir and fixed off-nadir mapping

• Low Altitude Mapping Orbit (LAMO): – Beta angle = 45-50º, Incl. = 90º – Duration 404 orbits (92 days) – Nadir pointed for GRaND – HGA-on-Earth for gravity (some LGA tracks)

C. Raymond SBAG12 06 Jan 2015

Slide 13

Ceres Mission Timeline

4b. – FC coverage 5b. – FC topography 7b. – VIR HAMO

1 – Density 2 – Spin Axis

3b. – High-res Gravity field 6abc. – GRaND elemental abundance

7b. – VIR Survey

C. Raymond SBAG12 06 Jan 2015

Slide 14

Preview of RC3

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Three full rotations of the lit side are obtained in the north, at the equator, in the south, as well as limbs and high phase imaging on the dark side.

17000 km radius

C. Raymond SBAG12 06 Jan 2015

Slide 15

Plume/Exosphere Detection

• The RC3 observations will be the best opportunity to see material emitted or lofted from Ceres’ surface – VIR team has used their simulation tools to predict the ability to

detect the putative flux of 6 kg/s estimated from Herschel detection (Küppers et al., 2014) • By averaging many spectra together, the expected signal can be

observed with SNR of 2-3 – FC images at high phase are expected to be able to see dust

• Dawn’s payload is well suited to searching for evidence of activity on Ceres’ surface – Look for recent and past deposits of outgassed material (and ice) – Constrain the thermophysical properties – Link surface composition to geologic processes

C. Raymond SBAG12 06 Jan 2015

Slide 16

Upcoming Events

• First look from Approach results at LPSC – Press conference likely in late Feb/early Mar

• “I C Ceres” Outreach event at Caltech May 9th

• Resolved mapping results from Survey at IAU in August and EPSC in Sept

• More complete results at AGU in Dec

C. Raymond SBAG12 06 Jan 2015

Slide 17

Here we come!