aerospace engineering department sd2: status and on comet science p. di lizia, f. malnati, p....

Aerospace Engineering

Department

SD2: Status and On Comet Science P. Di Lizia, F. Malnati, P. Francesconi, A. Ercoli Finzi, F. Bernelli-Zazzera

RLSW #4 Venice 2009

Aerospace Dep.

Pierluigi Di Lizia 2

SD2 Status

SD2 Open points Cruise phase Post Hibernation phase Comet phase

First Science Sequence (FSS) Requirements Proposed sequence

Long Term Mission (LTM) SD2 Facility Perforation Strategy Test campaign Preliminary Results

Agenda

RLSW #4 Venice 2009

Aerospace Dep.


In flight tests performed: Commissioning (4 blocks)

– Electronic behaviour tests

– Carousel movements

– Volume Checker movements

Active checkout ( 3 checkouts)– Carousel movements

– Drill rotation

– Drill translation

– EEPROM refresh

Passive Checkout ( 6 checkouts)– EEPROM content check

– Electronics switch on

– Position resolvers switch on

SD2 Status

(switch on SD2) OK

(4 rotations) OK

(2 movements) OK

(20 rotations) OK

(4 movements) OK

(2 movements) OK

OK

OK

OK

OK

Results

RLSW #4 Venice 2009

Aerospace Dep.


Fully commissioned: All mechanical items of SD2 have been tested during cruise phase

SD2 Status

Mechanical unit(including Drill)

SD2 is ready for comet phase

Electronic unit

Carousel

RLSW #4 Venice 2009

Aerospace Dep.


Required (or desired) activities for next active checkouts:

Carousel movements Drill rotation Drill translation EEPROM Refresh (during PC#12)

SD2 OPEN POINTS: Cruise phase

RLSW #4 Venice 2009

Aerospace Dep.


Test definition Complete test of SD2 is recommended after hibernation

• Carousel movements

• Drill rotation movement

• Drill translation movements

• EEPROM refresh (Mandatory)

Constraints about• Power budget

• Data rate

• Access to Rosetta (RF link)

• Other subsystems and experiments activities

SD2 OPEN POINTS: Post hibernation phase

No activities foreseen during SDL phase

RLSW #4 Venice 2009

Aerospace Dep.


Decisions for both phases:

First Science Sequence How many holes How many samples from each hole Which ovens shall be used to release samples Use of Volume Checker

Long Term Mission Use of SD2 to perform qualitative analysis of mechanical

characteristics of comet soil

SD2 OPEN POINTS: Comet phase

RLSW #4 Venice 2009

Aerospace Dep.


SD2 FSS: Requests (1/2)

Reference Documents: Philae Science Objectives [RO-LAN-L1-1000; Issue 1.1 Draft;

January, 02, 2009]

Requests:

CIVA M/V Requests # of holes # of samples Depth Oven type

ROS-PHI-CIV-FSS-002

Analyze samples from different depths and location

2 4 Different depths (TBD)

MTO

CIVA M/I Requests # of holes # of samples Depth Oven type

ROS-PHI-CIV-FSS-003

Analyze samples from different depths and location

2 4 Different depths (TBD)

MTO

RLSW #4 Venice 2009

Aerospace Dep.


SD2 FSS: Requests (2/2)

COSAC Requests # of holes # of samples Depth Oven type

ROS-PHI-COS-FSS-003

Collect 2 samples: 1 from deepest location, 1 from surface

1 2 1 from deepest 1 from surface

1 MTO 1 HTO

PTOLEMY Requests # of holes # of samples Depth Oven type

ROS-PHI-PTO-FSS-001

Load HTO1 with a surface sample, HTO2 with a sample at maximum depth

1 2 1 from surface 1 from deepest

2 HTO

ROS-PHI-PTO-FSS-002

Load MTO with sample and rotate oven between CIVA and Ptolemy

1 1 TBD 1 MTO

ROS-PHI-PTO-FSS-001

Analyze the coma at various epochs/solar distances

N.A. N.A. N.A. 1 HTO

RLSW #4 Venice 2009

Aerospace Dep.


SD2 FSS: # of holes - # of samples

Required Depths

Surface Max Depth

Hole 1

Sample 1 MTO 1 under CIVA M/V MTO 1 under CIVA M/I

Sample 2 HTO 1 under COSAC

Sample 3 HTO 2 under PTOLEMY

Sample 4 MTO 2 under CIVA M/V MTO 2 under CIVA M/I – PTOLEMY

Sample 5 MTO 3 under COSAC

Sample 6 HTO 3 under PTOLEMY

Hole 2



RLSW #4 Venice 2009

Aerospace Dep.


SD2 FSS: Proposed Sequence

Seq.

DescriptionDuration

[h]Consumption

[Wh]Oven Depth Instrument

PTO HTO 0 - PTOLEMY 0.57 2.20

H1S1 MTO 1 Surface CIVA 3.83 21.10

H1S2 HTO 1 Surface COSAC 2.00 10.70

H1S3 HTO 2 Surface PTOLEMY 2.00 10.70

H1S4 MTO 2 Max CIVA-PTOLEMY 6.65 34.81

H1S5 MTO 3 Max COSAC 3.49 19.58

H1S6 HTO 3 Max PTOLEMY 3.49 19.58

H2S1 MTO 4 Surface CIVA 3.83 21.10

H2S2 MTO 5 Max CIVA 5.85 33.16

Total: 31.70 172.93 Low Drill translation velocity (2 mm/min) for H1S1 and H2S1, and during

drilling to maximum depth Duration and consumption do not include stand-by phases

RLSW #4 Venice 2009

Aerospace Dep.


SD2 FSS: Mission Plans; HK, SC Packets

Necessary mission plans: 30

MP Description # of words bit

1 Drill bite rearming 30 480

2 Sample retrieval 25 400

3 Sample release 22 352

4-7 Drill down high and low velocity to surface and maximum depth

100 1600

8-30 Ovens’ positioning 322 5152

Total: 499 7984

House-keeping (HK) and Science (SC) Packets

Packet # of packets Mbit

HK 481 2.07

SC 4544 19.56

RLSW #4 Venice 2009

Aerospace Dep.


How to sample the comet

Drilling phase Sampling phase Discharge phase

Sampling tube

Drill bite

Comet soil

Oven

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Aerospace Dep.


SD2 Scientific Instrument

Correlation analysis between drill telemetry data and the mechanical characteristics of the perforated material

Tool

Scientific Instrument

(material parameters) = f (telemetry data)?

Experimental approach

SD2

RLSW #4 Venice 2009

Aerospace Dep.


SD2 DIA Facility (Laboratory)

• Strain gauge equipped with an amplifier and the conditioning system

• Current sensor

• DC Power Supply

• Low-pass digital filter

• Data Acquisition device

• Labview Software

• MATLAB

SD2 DIA Facility

RLSW #4 Venice 2009

Aerospace Dep.


Simulation of different sampling scenarios,

according to different on comet surface conditions.

SD2 Facility - Specimen

GRAPHITIC-FOAM

MULTI-LAYERGASBETON

RLSW #4 Venice 2009

Aerospace Dep.


Perforation strategy - Material Characteristics

GASBETON• Fragile material• Low density (~500 kg/m3)• Porous composition

GRAPHITIC-FOAM• Fragile material• Low density (560 kg/m3)• Porous composition

RLSW #4 Venice 2009

Aerospace Dep.


The contact between cutting and surface is asymmetrical, with an asymmetrical distribution of cutting stress

1) Test 20°2) Test 60° F

CFL

Simulation of SD2 operation on irregular cometary surface

Test campaign - Inclined surface

RLSW #4 Venice 2009

Aerospace Dep.


Goal: Drill behaviour analysis(discontinuity of force and torque)

First layer: mix of concrete material

Second layer: gasbeton

Test campaign - Multi-layers specimen

RLSW #4 Venice 2009

Aerospace Dep.


First layer: dry graphitic-foam

Second layer: frozen graphitic-foam

Goal: Drill behaviour analysis(discontinuity of force and torque)

Test campaign - Multi-layers specimen

RLSW #4 Venice 2009

Aerospace Dep.


Minimum Rotation Speed

Experimental campaign with different specimen categories:

• Imposition of decreasing drill rotation speed values • Identification of the minimum rotation speed required to drill the specimen without stepper motor stop

Creation of a DATABASE of correlations between minimum speed value

and the material characteristics

Perforation strategy - Experimental Approach

RLSW #4 Venice 2009

Aerospace Dep.


Test campaign - Gasbeton

Gasbeton drilling:

Ct = 4 Vt = 10

Cr = 1 Vr = 18

RLSW #4 Venice 2009

Aerospace Dep.


Dri

ll R

ota

tio

n s

pee

d l

evel

s

Drill Translation speed levels

Test campaign - Gasbeton

RLSW #4 Venice 2009

Aerospace Dep.


Preliminary Results

SD2 could be used as a scientific instrument in order to retrieve qualitative mechanical information about comet soil

The procedure about the soil analysis is both time and power consuming

Several mission plans need to be uploaded

Several laboratory tests must be implemented: The database about different soil mechanical characteristics The correct sequence of drilling test in order to perform the test in best

way without risk

It could be useful in case of some failure of other experiments (backup solution)

Aerospace Engineering

Department

SD2: Status and On Comet Science P. Di Lizia, F. Malnati, P. Francesconi, A. Ercoli Finzi, F. Bernelli-Zazzera

aerospace engineering department sd2: status and on comet science p. di lizia, f. malnati, p....

Documents

sd2 fss

drill sd2

pierluigi di lizia

comet phase slide

sd2 status switch

cruise phase slide

mechanical items of

sdl phase slide