Solar Orbiter Remote Sensing Payload Working Group

1
Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Monday 25 November Tuesday 26 November (Room
Einstein) Start 1100 PWG Plenary 1 - Welcome
and introduction (Marsden) - Aims of meeting
(Marsden and Rando) - Status of Solar Orbiter in
ESA (Marsden/Peacock) Remote Sensing Splinter
1 - Status of PDD inputs (Appourchaux) -
Discussion of each instrument PDD in turn
(Harrison/Fleck) (what is needed, what is
outstanding and who can supply details?)
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Remote Sensing Splinter 2 Feasibility/Technical
Actions and Studies - Summary of status of
actions (Harrison) - Open discussion on
recommendations to ESA based on actions - What
next? Completion of remaining actions? Report?
How do we relay recommendations to ESA? -
Solar Orbiter Scientific Goals Plenary 2 -
Summary of Splinter Sessions (Harrison/Wimmer) -
Future PWG activities - AOB
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Feasibility/Technical Studies Actions Aim To
demonstrate feasibility of paylaod, especially
given the thermal particle environment and the
mission limitations (e.g. telemetry, autonomy).
Make recommendations to ESA. Co-ordinate/request
studies. Method By identifying the technical
challenges (last meeting) and addressing specific
actions. Remember We are demonstrating
feasibility, nothing more. Comment The PDD
activity is an extra, parallel demand on us,
but it is necessary for us to do what we can to
take advantage of it.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Feasibility/Technical Studies Actions Last
Meeting Technical challenges identified and
listed. Action list set up and assigned. Web
site Web site set up at http//www.orbiter.rl.ac
.uk/solarorb/rspwg/, lists actions, provides
notes from initial meeting, action spread sheet,
Action Completion reports. Other documents (e.g.
PDDs) can be found at http//zeus.nascom.nasa.gov/
bfleck/Orbiter/PLWG/Documents/.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Feasibility/Technical Studies Actions
Progress to date 73 actions listed. 22 ticked
off, i.e. 30 . Not very impressive response from
some especially as some of the actions are
rather basic, e.g. telemetry back of the
envelope calculations. Next Step Assess
remaining actions Pull out recommendations/reques
ts Discuss report/schedule. Warning Next Chair
of SSWG (Peter Cargill) better demonstrate
feasibility by Spring 2003. AO June 2004 (1 year
after BC)?
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Recommendations 1. Pointing It is recommended
that a hard mounted, joint-pointing policy be
adopted, which is in keeping with the science
goals of the mission, but will save mass and
power. 2. Image Stabilisation It is recommended
that the VIM signal be used for all instruments
that use an image stabilisation system, to save
mass and complexity. 3. Resources All options
should be considered by the Project to maximise
the payload mass, telemetry, memory capacity and
power the scientific return is increased with
increased payload resource.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions Some
completed actions make recommendations. If they
are concerned with critical technologies
(especially involving more than one instrument)
or are spacecraft-wide/mission issues, then they
must be discussed and passed on to ESA if ESA
are serious about performing studies, we must
request them formally now.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 4. Thermal
Control Given the extreme thermal environment,
it is recommended that there be a study of a
spacecraft-wide approach to thermal control
(Action 1.1/1.2 EUS). e.g. What actions can be
taken at a spacecraft level to dampen the thermal
variations, to dissipate heat, to allow access to
open space etc
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC

• Other Recommendations from Actions
• 4. Thermal Control (continued)
• Note The RAL/Cranfield and MSSL studies stress
  that it is not so much the absolute temperatures
  that kill you, as the variations! (Possible
  actions Reduce aphelion? Heat switches? Heaters?
  Adaptive optics?)
• e.g. 1500 mm CFRP will expand by 50-75 micron
  with variation of 100oC.
• How do you interface to spacecraft? Same
  materials?
• Do we use adaptive optics or is optical depth
  of focus OK for this?
• Note also the use of CFRP probably means a
  100-130oC upper limit (outgassing, glue)?

10
Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 4. Thermal
Control (continued) However, only one
instrument input has addressed the thermal
action. Thermal feasibility has NOT been
demonstrated for almost all insruments. This must
be done a.s.a.p. if our desire to have a Solar
Orbiter mission is to be taken seriously. However,
the lack of any spacecraft input on the thermal
interface between instrument and spacecraft is
hindering thermal modelling. It is a design
driver. We need input from the Project on the
thermal interface, on thermal policy and views to
space. This is a request to the Project now.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 5. ESA Study
of LCVRs Liquid Crystal Variable Retarders
(LCVRs) may be critical to the operation of VIM
UVC - (as polarization modulators). No LCVR has
been in vacuum for a long period put into
extended operation after a long time, the
radiation impacts must be considered. Is this a
spacecraft issue or just for the instrument(s)
involved? (Action 2.2).
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 6.
Contamination Control (i) Instrument teams must
adopt a stringent contamination policy in the
laboratory, but also in operations (e.g. long
out-gassing period) (Action 3.1). (ii) A test
activity on the degradation of selected optical
surfaces under high irradiation and particle flux
levels should be recommended as part of a Solar
Orbiter development programme (Actions 3.1
3.5). Can we define such a test and the materials
to test?
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 6.
Contamination Control (continued) Test 1
Contamination of optical surfaces under high
irradiation levels. Basic test EUV/UV
reflectivity of optical surfaces at normal
incidence under extreme temperatures, under
vacuum. Surfaces SiC, SiC gold coated, what
else? Temperatures 0oC to 100oC, perhaps
higher? Cycles to represent orbit. What
facilities are available for this? Who can do it?
Action to define test Udo, Luca?? To be relayed
to ESA now.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 6.
Contamination Control (continued) Test 2
Degradation of optical surfaces from particle
impacts. Basic test Examine optical
surfaces/coatings after exposure to selected
particle environments, perhaps also under high
temperatures. Look for blistering and sputtering
effects. Surfaces e.g. SiC gold coated, what
else? (see note on multilayers later) Particles
Proton and ion beams. What facilities are
available for this? Who can do it? Extend
previous CDS study? Action to define test
Harrison? To be relayed to ESA now.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 7. Detector
Development Most instruments call for detector
systems now under development, e.g. 4kx4k 5
micron back-thinned APS or diamond. (Actions
10.3-10.5). Does this require any effort from ESA
or is it all under control?
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 8.
Autonomous Target Selection/Pointing After a
feasibility study (Action 10.7), we recommend
that this facility be adopted for Solar Orbiter,
to ensure the best scientific return. Concerns
over instrument/mission safety must be
addressed. 9. Planning and Operations Cycle A
study of the possible planning and operations
scenario (Action 10.9) has recommended a 150-day
planning cycle, possibly with a dedicated science
centre. ESA must examine the study report and
decide on an approach prior to the AO.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC
Other Recommendations from Actions 10.
Operations Scenario Memory It is recommended
that the Solar Orbiter mission is run with a full
150-day observation period and that on-board
memory is maximised in order to obtain the best
encounter observations. (Action 10.9). 11. Solar
Orbiter Goals The Solar Orbiter goals are NOT
well/properly defined. This is beginning to
hurt i.e. potential proposing groups are not
really able to tune their instruments to the
priority goals. (See post-Tenerife document). It
is recommended that the SOPWG address this now.
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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC

• Other Recommendations from Actions
• 12. Multilayers Action 1.6 not completed.
  However presentation by David Windt (Columbia,
  New York) at MSSL on multilayer stability
• For traditional multilayers, e.g. Mo/Si,
  Mo2C/Si, have tested to high temperatures (see
  Stearns et al. J. Appl. Pys. 67, 2415, 1990). No
  effects up to 100oC. No real concerns up to 150oC
  but degadation seen at 200oC. Can we arrange
  repeat tests with 0-100oC cycling to mimic orbit
  and long-term effects?
• No reports of degradation due to radiation (e.g.
  Kortright et al., J. Appl. Phys. 69, 168, 1991).

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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC

• Other Recommendations from Actions
• 12. Multilayers (continued)
• The effects of particles have not really been
  tested. Possibly a problem is the multilayers are
  not well protected. Should we include multilayers
  in the particle test activity on surfaces?

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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC

• Real Concerns
• Thermal feasibility has NOT been demonstrated for
  most instruments
• Thermal policy/interfaces from S/C required to
  progress beyond basics
• Multilayer and optical surface integrity at high
  temperatures and particle fluxes needs to be
  established
• Instruments must be able to cope with latch-up
• We must have an automated instrument safing
  policy/plan/procedure
• We really need a set of focused goals for Solar
  Orbiter!

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Solar Orbiter - Remote Sensing Payload Working
Group Mid-term meeting - 25-26 November 2002,
ESTEC

• Schedule/Remaining Activities
• Refine PDDs as much as possible - because that
  will influence the mission we get!
• Complete action studies by end of February 2003.
• Write final report by April/May 2003 (based on
  Action Response Forms) - including all
  recommendations.
• Any clear recommendations MUST be passed to ESA
  as they come up.
• Define any studies/test activities as agreed,
  and pass on to ESA now!
• Recommend a set of focused goals for the mission!