solar orbiter – mission update

Solar Orbiter – Mission Update

• Reference launch: Oct 2013 (back-up: May 2015). • Baseline mission design retained by both

contractors after Mid Term Meeting (direct injection, SEP, 1.5 yr cruise, 3.2 yr nominal science phase, 2.4 yr extended science phase).

• Back-up mission designs are available but all impact either on cruise phase duration (up to 5 yr) or on total cost and risk.

• Strong commonality and programmatic link with Bepi Colombo mission is confirmed (e.g. HGA usable down to 0.3 AU from Sun).

• No technical show-stoppers identified to date. ‘Behind shield’ design is confirmed as most appropriate. Solutions available.

• Tight management of onboard resources is required (mass, thermal loads, TM link).

• Overall mission complexity lower than Bepi Colombo.

Industrial Assessment Studies – key results


Remote Sensing Instruments:

Ground rules from Integrated Payload Study

- ‘1m class’ instruments principle (as instrument size impacts on P/L and spacecraft dimensions larger mass)

- ‘0.5 arcsec/pixel imaging/1 arcsec/pixel spectroscopy’ principle (as enhanced resolution implies larger apertures unacceptable heat loads and again larger mass)

- Commensurate focal plane detector size (Max 2k x 2k, as large array size implies large data volume excessive TM needs)

- Co-alignment of all RS units and design harmonisation (e.g. single technology for focal plane detectors)

- Resources demands compatible with final PDD values and based on a realistic and thorough estimate.

- Keep it simple approach…


Payload Definition Document (PDD) Consolidation Meeting – ESTEC Nov 1, 2004

Achieved milestones:- Industrial science payload study - Jan-June 2004- Internal ESA CDF study - Mar 2004- Parallel competitive industrial studies (Astrium, Alcatel) – KO

end of April, Mid Term Review - Sep 2004- PDD revision and release of v3 - Sep 2004- Draft Technology Development Plan - Oct 2004

Ongoing:- Consolidation of Payload Definition Document- Consolidation of the Technology Development Plan



General Notes:- PDD Version 4 is the last one before the AO, i.e.

it is the one we must get right. Version 3 is not ‘final’.

- Final presentation from Industrial Study – Dec 14-15 at ESTEC. PWG chairs to attend.

- AO nominally at end of 2005. Early 2006 more likely (especially in light of national funding and NASA situation.



Technology Development:- PWG requested development/test activities, in particular

support for detector development and optical surface/coating environmental (particle and thermal) tests. ESTEC now responding.

- Activities identified by ESTEC for remote sensing payload:VIM – Fabry-Perot filterVIM – Polarisation modulation packageVIM – Large narrow bandpass entrance filterEUS – Radiator grid entrance filterVIM/EUI/EUS/COR/STIX – DetectorsALL – Data compressionALL – Solar environment test facility.



Common Detector Needs:

Given need from ESA for 1 m instruments, and 1 arcsec spectroscopy (pixel size) & 0.5 arcsec imaging, i.e. 150 km at perihelion for EUS and 75 km for VIM, EUI, is there a common need for detectors of 2 k x 2 k at 10 or 8 micron rather than different values (e.g. the 4 k x 4 k 5 micron detector for EUS is not driven by spatial resolution/instrument length).

Does this cater for EUI, EUS, VIM, COR? Consider wavelength requirements, coatings (if any), compatible with MCP if COR needs it? Would it still be possible for EUS to have 5 micron array (for smaller instrument) – risks, optical performance (1 m instrument).



Data Compression:

Seen as critical BUT action is delayed until instruments better defined – beyond initial studies already done through PDD activity.



Solar Environment Test Facility:

Test facility of up to 23 solar constants envisaged by ESTEC team. Definition meeting this Friday at ESTEC. Sized for single instruments. Would not include particle environment, so additional tests would be required.

Can this cover the requirements of the PWG? Who organises the test programme?



EUS Radiator Grid Entrance:

EUS studies suggest that the radiator grid entrance filter may add complexity and risk and that it is more elegant to focus on the primary mirror plus the reflector/heat stop as a ‘simple’ approach.

Action: Having the filter is not a requirement. We need to show that the latter is OK for ESA to remove the filter option from their Technology Development Activity list. If the primary mirror is the main thermal ‘item’, are we comfortable with SiC – i.e. not worry about the potential degradation of coatings (gold, multilayers). Comment on impact of this on wavelength selection.



Pointing & Stability:

Requirements (note x is in the solar direction):

Parameter Line of sight (x) Around line of sight

Absolute pointing error < 2 arcmin < 20 arcmin

Pointing drift error < 1 arcmin/10 days < 10 arcmin/10 days

Relative pointing error < 1 arcsec/10 sec < 2 arcsec/10 sec

RPE ‘achieved’ 0.5 arcsec/10 sec

Note: 2 arcmin at 0.2 AU is equivalent to 24 arcsec at 1 AU.

Do we need stabilisation systems for a 1 arcsec/pixel spectrometer or a 0.5 arcsec/pixel imager? (EUI PDD was listed as 0.1 arcsec/10 sec when pixel was 0.25 arcsec).



EUI Issues:

Assume 9-10 micron pixels.

Aperture: Astrium ‘scale down’ had resulted in 1 cm! Key is instrument size, mass, thermal situation. PDD back at 2 cm but is not a requirement.

Mass (kg)

Data rate (kb/s)

Pixel size (arcsec)

Pixel size (km @ 0.2AU)

Array Instrument Size (cm3)

PDD#1 48.6 20 0.25 37 2k x 2k 180x44x25

PDD#3 15.5 20 0.5 75 2k x 2k 95x50x30



EUS Issues:

PDD#1 and 3 assume 5 micron pixels. PDD#3’ assumes 8-10 micron pixels.

Mass (kg)

Data rate (kb/s)

Pixel size (arcsec)

Pixel size (km @ 0.2AU)

Array Instrument Size (cm3)

PDD#1 25 17 0.5 75 4k x 4k 160x30x40

PDD#3 16 17 1 150 2k x 2k 80x15x15

PDD#3’ 20 17 1 150 2k x 2k 96x24x18

Solar Orbiter – EUV Spectrometer (EUS)

4th Consortium Meeting – November 4, 2004

http://www.orbiter.rl.ac.uk

Agenda:

09:30-12:30

Solar Orbiter and EUS Status Richard Harrison/Peter Cargill

Report on Imager Plans Louise Harra

Scientific Issues Peter Young

Mechanical & Thermal Overview Eric Sawyer, with Doug Griffin, Bryan Shaughnessy.

Optical Design Kevin Middleton, Roger Thomas, Luca Poletto, & Clarence Korendyke (EIS/gratings)



http://www.orbiter.rl.ac.uk

Agenda:

13:30-17:30

Detector Status Nick Waltham (APS), Udo Schuehle (BOLD)

Wavelength Selection (Discussion) Chair: Peter Young

Consortium Responsibilities (Discussion) Chair: Richard Harrison

Schedule to AO (Discussion) Chair: Richard Harrison



Schedule to AO:

AO End 2005/Early 2006

Proposal draft production From November 2005

Pre-Proposal Consortium Meeting ~ September 2005

Detailed design phase From January 2005

‘Post Feasibility Study’ Consortium Meeting Spring 2005

‘Feasibility phase’ Two basic design concepts established

Optical, Thermal, feasibility/tradeoffs

Consolidate (in parallel) wavelengths

Define institute responsibilities

Hardware Telecons/Meetings???

ESA Industrial Study Input/PDD4 December

Weekly Local Meetings at RAL Started…

solar orbiter – mission update

Documents

bepi colombo mission

baseline mission design

pdd version

backup mission designs

pdd revision

final pdd values

detector development

industrial study