ESA UNCLASSIFIED

ESA UNCLASSIFIED – For Official Use

Proba-V QWG-2

Platform status

28 October 2015

PROBA-V QWG-2 28-29 October page 2ESA UNCLASSIFIED – For Official Use

Orbit status


Orbit status

Orbit evolution:

LTDN well within 10:30 – 11:30

LTDN reaches 10:30 around Sept 2017

Stays well above 10:00 after 5 years


Platform status


Platform key parameter


Platform key parameter

1. The platform availability is around 99.9%. The autonomous reconfigurations have a very small impact on the overall performance.

2. In the last 10 months, there was no safe mode

3. All platform subsystems are nominal

4. The thermal situation is very stable, showing the expected trends in summer and winter

5. There are 2 new anomaly reports opened in the last 6 months

a. PROABV-12, which is related to a single occurrence of a problem in the MMM downlink

b. PROBAV-13, which is related to a single occurrence of a non-detected single bit upset in the star tracker memory. The satellite autonomously detected the issue and reconfigured to the redundant star tracker.


Status AOCS: pointing performance

Observation mode: obtained pointing accuracies

Error at confidence level

Error required[arcsec]

Error measured nominal [arcsec]

APE 68% 15.3

APE 95% 360 23

APE 99.7% 38.2

RPE 1.5s 95% 80 3.3

The AOCS pointing performance is far better than the requirement


Status AOCS units

Unit Status remark

Star tracker nominal Temp Head nominal (average -12 deg). On 05-10, a SEU triggered an on board FDIR. It has occurred in the eclipse part of the orbit with no impact on the mission. Proper automatic recovery, no safe mode.

GPS receiver nominal As from 22/12/2014, the GPS is continuous active (previously, the GPS was OFF during the sun mode part of the orbit). The operations are very stable (99.2% fix).

magnetometer nominal

Reaction wheels nominal No wear detected

Magnetic torquers nominal

AOCS IF nominal

AOCS overall status: all is nominal and performances met by far


Power summary including budget comparison

Mode Bus average consumption [W]

S/A average generated power [W]

Energy budget margin

Minimum battery voltage (max = 29.2V)

Nominal mode

68.8 100 >40% 28 V

Power budget largely positive Very stable in time

Status Power


Status Power

6/14 7/14 9/14 11/14 12/14 2/15 4/15 5/15 7/15 9/15 10/150

50

100

150

200

250

incoming solar power evolution

average Total solarmaximum Total solar

Date

Sola

r arr

ay p

ow

er


Status Power

6/14 7/14 9/14 11/14 12/14 2/15 4/15 5/15 7/15 9/15 10/1528.5

28.6

28.7

28.8

28.9

29

29.1

29.2

Battery voltage

averagemaximum

Date

BA

ttery

volt

age


Status Power

6/14 7/14 9/14 11/14 12/14 2/15 4/15 5/15 7/15 9/15 10/150%

10%

20%

30%

40%

50%

60%

Power margin

average

Date

Pow

er

marg

in


Status Power Units

Unit In-orbit status

Battery nominal No specific issues found. Battery voltage nominal. An average value of 0A is observed as the battery charging and discharging are perfectly balanced. Temperature (average 12 deg, min 9 deg > min of 6 deg) nominal (no heater required)

Solar arrays nominal Total solar array current as expected

Power conditioning (ADPMS)

nominal Power as expected

All units within power budget

The power situation is very stable, showing no apparent degradation of the solar arrays, battery, nor power distribution system


Data handling status

1.

Unit Commissioning status

remark

ADPMS nominal Only events are single bit error (automatically corrected) in the MPM (2 occurrences in last 6 months)

Mass memory Nominal with work around

Latch-up behaviour detected in orbitOn board S/W work around in place

Processor load

• 8 % in safe mode (average)

• 20 % in nominal mode (average)

Comfortable processor budget margin


Mass memory anomaly statistics

• Location in orbit: almost always over the South Atlantic Anomaly

• Occurrence: on average once per 2.8 days (between 2 and 4 days, max 17 days)

• Very stable

• Potential data gap: 4 min per occurrence (when over land)

• There is no increase in the frequency of the events

Data handling mass memory anomaly


Data handling Mass memory usage

MMM usage was never such that non-transmitted data was erased


RF S-Band

S-band system summary


S-band uplink nominal

S-band downlink nominal

• S-band system operationally working as expected

• Link budget within expectations


RF X-Band

X-band system summary


X-band nominal

X-band experimental unit(tech demo)

nominal

New development for Proba-V

Both units main and experimental used daily operations

Comfortable link margin allowed to tune the TX power from 38 dBm to 36 dBm


RF S and X band duty cycle


OBSW status

1. Image 1: OBSW V2.0.6 (launch version)

2. OBSW V2.1.0 (updated after launch on 08/07/2013). This OBSW includes the automatic recovery after a MMM SRAM functional disruption. It had some issues with the handling of the MMM wrap around (during erase and transmit). Other changes are the handling of the GPS in eclipse and tuning of specific FDIR.

3. OBSW V2.1.1 (updated after launch on 15/10/2013). This OBSW provides a solution for all issues found on OBSW V2.1.0

4. Image 2: OBSW V2.1.2. Used as from 11/08/2014. This OBSW provides a solution for all issues found on OBSW V2.1.1.

• More robust Autonomous reconfigurations

• Wheel FDIR speed (out of limit)

• GPS control (more robust against radiation)


Instrument status


Instrument Status

• Fully functional

• No single FDIR triggered except SWIR soft latch-up

• False alarm (linked to integration time)

• In average less than 1 soft latch-up per month

• All calibration requests were correctly executed.

• SWIR dark current (see further)


Instrument Thermal

Optical bench thermal variation

~ 1°C variation per orbit

~ 1.5°C variation per day

Very stable

Confirming excellent thermal performances of radiator and bench

Unit Value

maximum -4 to -6.5 degC

average -6 to -8 degC


Instrument thermal

Move towards lower wavelength when T decreases

When T (winter), A in blue but in NIR in Red and SWIR


Flight Segment evolution


Planned Flight Segment Evolutions

1. PV-OPS#9-4: Automatic Moon calibration

a. Moon calibration requires ground preparation (moon ephemeris, …)

b. Full automation requires involvement of NGC, QS, Spacebel so easily 100-200keuro

c. Not justified

d. Proposed not to do it


Planned Flight Segment Evolutions

1. A1.7 : extended northern coverage (possibly like Sentinel-2 set to 82 degree SZA) during Winter to 82° SZA (Sun Zenith Angle).

a. AOCS-SW calculates the dayflag based on the sun being 10 degrees above the horizon at the nadir location

b. 10 degrees is a global parameter in the AOCS-SW, can be easily changed. There is no impact on the GNC loop

c. Parameter was patched to 8 degrees on board on 27th October only on S/C SDRAM (in case of MMM reconfiguration, automatic update from Redu)

d. VITO/Redu to check dayflag behaviour from in flight data

e. VITO/Redu to further modify configuration if needed (land/sea mask, latitude restrictions)

f. VITO to provide feedback on correct behaviour of patch --> value to be increased or decreased accordingly if needed

g. ESA to assess the overall impact on the downlink volume

h. QS to assess the MMM memory status and power budget

i. If everybody happy: patch performed also in the startup TCs list


Report on anomalies


Report on anomalies A1.17 decompression error

1. linked to the packet processing onboard FPGA based): wrong pointing of the start of a packet within a frame inside the frame header

2. The root cause is still unknown

3. strange thing remains why this issue seems to be degrading over the last months...

4. if the problem is a bug in the mass memory FPGA, then it is either there or not. One explanation for this could be that the bug is only apparent in specific circumstances

5. Either we find the circumstances which trigger the issue onboard and avoid these or we correct the errors on ground

6. Issue seems systematic and consistent

7. Still unknown whether the errors are linked to missing packets or to a wrong content of the packets

8. So far no success to identify the circumstances or to provide a correction on the ground


Report on anomalies A1.17 decompression error


Report on anomalies: SWIR detector

• Macroscopic view (average dark current evolution): in line with prediction

• Pixel view

• Increasing amount of pixels with very high stable dark current

• (few and slowly increasing) Pixels with unstable dark current

• Not reported from ground radiation test

• Ground radiation raw data under investigation in order to detect the same problem and to predict trend accordingly


Report on anomalies: SWIR detector

Dark current± double every year

This is in line with ground prediction (radiation test)

ESA UNCLASSIFIED – For Official Use Proba-V QWG-2 Platform status 28 October 2015.

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