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Q&A for Solar Orbiter Payload AO

Q&A for Solar Orbiter Payload AO

29 Oct 2007 - NGD not in revised PDD
Q: Is it true that the NGD was excluded from the revised PDD for technical reasons. If so, what were the reason(s)?
A: The exclusion of the NGD instrument from version 6 of the PDD is a result of the science prioritization from the Solar Orbiter/Sentinels joint Science and Technology Definition Team. In their report, it was recommended not to allocate spacecraft resources to a dedicated sensor on Solar Orbiter, in part owing to the difficulty of accommodating the instrument behind the heat shield. It was suggested, however, that more limited neutron and gamma-ray measurement capabilities might be achieved by the EPD instrument suite on Solar Orbiter provided this did not lead to an increase in the allocated resources. This is the reason for the exclusion of the NGD instrument from the most recent PDD.
30 Oct 2007 - CZT development
Q: We were not aware of an existing ESA-funded, currently on-going CZT activity. Please let us know the details and possibilities for contact.

Concerning the development of CZT, we have concentrated on building up the capability of growing high quality material in Europe.
There is a contract running with Durham, Scientific Crystals (C 20493) under the ITI initiative with the following targets:

Phase 1 ITI Demonstration of the vapour phase growth of single crystal cadmium zinc telluride material – 6 months duration

  • Demonstrate the feasibility of growth of CZT using the MTPVT method
  • Determine the growth parameters using a bench top simulator
  • Expand existing CdTe models to simulate CZT growth conditions
  • Validate model with bench top simulator results

Status: This first phase has successfully been concluded

Phase 2 ITI Production of single crystal cadmium zinc telluride (CZT) for detector applications – 12 months duration

  • Fabricate a fully operational vapour growth system for the production of single crystal CZT from two binary sources
  • Adjust growth conditions to optimise the crystals for use as high energy radiation detectors

Status: Industrial reaction vessel built. Producing large area single xtal high resistivity. We hope to conclude this activity in Q1/2008.

We are still far from having a reliable source for CZT detectors in Europe, but at least, the first steps have been taken.

31 Oct 2007 - Maximum length of remote sensing instruments
Q: The PDD document reports a length for COR instrument of 80 cm (excluding the heat shield thickness). Is there the possibility of increasing the length? What is the maximum length the payload module can allocate to COR?

The maximum length for remote sensing instruments is 1 metre, as stated in the EID-A, section 4.6.2.

01 Nov 2007 - Contact for entrance window
Q: Are we allowed to contact Galileo Avionica to get a ROM estimate for the FM entrance windows? Or, has such an estimate already been given to the project and are you in a position to disclose it?

Instrument teams are allowed to contact Galileo Avionica for a quote for the entrance window cost. The contact person is

  Mr Giovanni Taglioni
phone: +39.08639062202
(who may then refer you to a commercial officer).

02 Nov 2007 - Instrument structural model
Q: Is the "thermal-structural model" a piece of hardware or a computer model?

A Structural Mathematical Model is required per EID-A section
Thermal Mathematical Models are required per EID-A sections,,
A Structural & Thermal Model (STM, hardware) and an Engineering Model (EM, hardware) are required per EID-A section
The schedule of deliveries (TBD for the mathematical models and TBC for the hardware models) is per EID-A section 8.8.3.

09 Nov 2007 - Baseline measurements for solar wind ions

We would like to bring to your attention that the baseline measurements for solar wind ions (i.e., the SW-PAS instrument) stated in Table 3-3 of the HELEX JSTDT report are significantly different when compared with those stated in the Solar Orbiter PDD. Please clarify if the information given in the HELEX report now represents the actual requirements.

The PDD requirements for SW-PAS are given on page 73:

    Normal Mode
    A typical time resolution of 3s for 3-D velocity distribution functions;
    FOV: ± 45° to Sun, ± 15° north/south at 5° deg resolution

    Burst Mode
    Measurements of 2-D distributions of solar wind protons and alpha particles to resolve typical growth times of instabilities, i.e., at a cadence of 0.1s

In contrast, the Prioritized Solar Orbiter Measurements for solar wind ions as stated in Table 3-3 (page 48) of the JSTDT report for HELEX are:

    Baseline Measurements for solar wind ions:
    Detailed 3-dim velocity distribution functions at 1 s time-resolution;
    FOV: ± 45° to Sun, ± 15° north/south, angular resolution of 2°

    Augmented Measurements for solar wind ions:
    Burst mode at 0.1s time resolution or better for protons for 1 dim

A: The difference in requirements between the PDD and HELEX Report likely has its origin in the JSTDT Plasma & Fields splinter group discussions where it was stated on several occasions that Solar Orbiter, being 3-axis stabilised, is more suited to kinetic physics (including rapid ion measurements) than Sentinels. However it cannot be expressly confirmed when and how the numbers that appear in the JSTDT report were decided.
With this in mind, the following approach is recommended: treat the more stringent figures in the JSTDT report as a target rather than a set of requirements that must be met at all costs. The first priority of the proposing teams should be to address the science goals of the joint mission. If additional science can be done within the resource allocations (in this case, telemetry in particular) this will only strengthen the proposal. It should be also kept in mind that an increase in the number of sensors or required resources places an additional burden on the overall payload accommodation.
12 Nov 2007 - Proposals from the U.S.
Q: (put to NASA on 03 Nov 2007)
Can NASA provide clarification as to what, if anything, that has been requested by ESA in the Solar Orbiter AO is to be included in a proposal to NASA under the FOSO amendment. We assume that the due date for any such submission is Feb 1, 2008. Is that correct? Are there any submissions by US PIs directly to ESA? If so can that be done by the US PI submitting to NASA and then NASA forwarding the documents to ESA?
  • In their response to the ESA Solar Orbiter Payload AO, U.S. proposers provide their proposal to ESA, according to the procedure described in the ESA AO. The selection will be performed by an ESA Payload Review Committee (= selection committee) which will include U.S. members appointed by NASA in consultation with ESA. Selection by ESA does not entail any funding by ESA. The procedure for U.S. proposers is identical to the procedure for any other (non U.S.) proposer.
  • Simultaneously, U.S. proposers provide their proposal to NASA in order to secure NASA funding, according to the NASA SMEX/FOSO procedure described in the NASA SMEX/FOSO. This procedure is similar to the procedure for any other (non U.S.) proposer, who also has to secure funding from a national agency.
  • Because of the respective AO schedules, U.S. proposers are required to provide within their proposal to ESA a NASA document certifying that their proposal has been received and accepted by NASA and declared compliant with the SMEX/FOSO rules. (Other proposers are required to include a full-fledged Letter of Commitment from their funding agency.)
13 Nov 2007 - Question 11 from the NASA SMEX/FOSO AO FAQ

Section 10.2 Reference Payload states that the "Nominal accommodation of all instruments has been defined with the exception of a wide-field heliospheric imager. With the caveats mentioned in the previous paragraph, it is anticipated that the available resources for a wide angle coronagraph/heliospheric imager will be in the range of 5-10 kilograms in mass, 5-10 Watts in power, and a telemetry bandwidth of ~20 kilobits per second." In section 3.6.3 of the ESA Payload Definition Document (PDD), there is a chart that defines the instrument accommodation maximum resources as slightly different. Which document (the SMEX AO Addendum or the ESA PDD) should we consider as the master for developing our proposal concept? 

NASA Response to Question 11:
The FOSO Amendment to the SMEX AO takes precedence over the ESA PDD.


ESA complementary response: The evaluation of proposals will be based on the ESA documentation including the EID-A, which contains a payload resource table. The EID-A is applicable. Since spacecraft resources are at a premium, a proposal with a higher mass will be graded lower than a proposal with an EID-A compliant mass. The mass range indicated by NASA's response is the range beyond which a proposal will not be examined. The same applies to the power and telemetry. Concerning telemetry, one should take into account that remote-sensing instruments will not operate along the whole orbit, therefore the bandwidth figure depends on the proportion of the orbit on which this particular instrument generates data. This resolves partially or wholly the discrepancy between the ESA and NASA bandwidth figures.

13 Nov 2007 - Question 13 from the NASA SMEX/FOSO AO FAQ

Section of ESA's Payload Definition Document, shows the Heliospheric Imager instrument mounted to the same side as a solar panel in figure 3.6.2. Straylight from the solar array makes it extremely difficult to meet filed of view requirements associated with the Heliospheric Imager. During the accommodation study, would ESA consider moving the solar panels to another plane while keeping the Heliospheric Imager instrument in the ram or anti-ram side and on the ecliptic plane? 

NASA Response to Question 13:
Moving the solar panels may be considered during an accommodation study.


ESA complementary response: The accommodation study will not start from scratch. It will be aimed at optimizing the accommodation of the instruments (including GHI/WFC) within the spacecraft, but not at fundamentally re-designing the spacecraft. In addition, in this particular case, alternatives to the baseline solar panel location have been considered already to a significant extent and result, as far as we know today, in solutions worse for the instrument than the current baseline.

13 Nov 2007 - Augmentation payload
Q: The AO for Solar Orbiter does not really exclude any of the instruments corresponding to the measurements defined by the Solar Orbiter Science Requirements Document, including those considered as High Priority Augmentation such as a Radiometer. In practice however, it seems that there is hardly any chance that a radiometer will be accepted, because the report of the Joint Science and Technology Definition Team (JSTDT) for HELEX clearly states on page 22: "Solar Orbiter's payload complement has been further streamlined by eliminating the following instruments included in the High Priority Augmentation category: Neutrals, Coronal Radio Sounding, and Total Solar Irradiance (TSI) (cf. "Solar Orbiter Mission Requirements Document")."
Is it worth the effort to prepare and submit a proposal for any of the latter instruments?
A: At present there are no spacecraft resources available to include any of the instruments of the High Priority Augmentation category as defined in the Solar Orbiter Science Requirements Document. Therefore, any proposal for an instrument in this category would be given a lower priority during the evaluation. In the very unlikely event that excess resources become available, the possibility of implementing one of these High Priority Augmentation instruments might then be reconsidered.
13 Nov 2007 - Instrument model philosophy
Q: Some doubts have arisen after reading the model philosophy specified on pages 128-129, section of EID-A (and not fully resolved after reading the Q/A dated 02 Nov). Particularly, could you clarify what you understand by PFM? Is it equivalent to the traditional QM? On page 129, the FM is missing, could you please specify the tests to be performed on this unit? And finally, could you please clarify which units require Thermal Vacuum testing?
A: Section of the EID-A describes the Satellite Model and Test Philosophy, not the instrument models. Its purpose is to give instrument teams an understanding of the satellite-level model philosophy and thereby an understanding of what will be done with the instrument models which they are required to deliver in accordance with the following section

The (satellite) PFM is not equivalent to the traditional QM but it does mean that part of the (satellite) qualification will be performed on the (satellite) Flight Model, hence its designation as Proto-Flight Model. However, we anticipate that relatively little will be qualified on the satellite PFM, since the primary structure will be qualified on the satellite STM and the electrical aspects will be for the most part qualified on the satellite EM. Designating the satellite flight model as PFM gives us some limited flexibility in this respect at satellite AIV level, for the case programme development identifies beneficial options in schedule and/or cost e.g. by re-using some part of the satellite STM into the satellite PFM. This also explains why the (satellite) FM is absent from the list on page 129.

At instrument level, instrument teams have some leeway to propose the model and AIV philosophy they deem most suitable. However they must remain compatible with the satellite-level philosophy as described by the EID-A, hence:

  • the instrument STM has to be put through thermal vacuum testing to ensure its capability to participate in satellite-level thermal vacuum testing; and the test should include thermal balance phases to ensure its representativity for the instrument.
  • the instrument EM is not required to go through thermal vacuum testing, since it will be used at satellite-level in the satellite EM, which is not scheduled to go through thermal vacuum. However, instrument teams may elect to perform thermal vacuum qualification testing on this model, making it an EQM. This is a classic approach. It greatly reduces the risk of discovering thermal problems too late, on the FM. It also avoids stressing the FM by acquiring qualification on it (thus making it a PFM). Depending on the make-up of the instrument, if it significantly saves resources without unduly increasing risk, it may also a good compromise to adopt a STM/EQM/FM approach for some more critical units and a STM/EQM/PFM approach for some less critical or better known units e.g. those only slightly modified from existing qualified units.
  • the FM and FS have to be put through acceptance thermal vacuum / thermal balance testing. If qualification has not been acquired on a QM or EQM, then the FM is actually a PFM and has to be put through qualification thermal vacuum / thermal balance testing.
A classic approach which can be recommended from experience, but which is not compulsory, is thus the following:
  • instrument models are an STM, an EM (not vacuum-tested), an EQM (flight-standard), an FM.
  • The qualification testing is performed on the EQM.
  • The FM is acceptance-tested.
  • After completion of qualification, the EQM becomes the FS (with minor refurbishment if/as applicable). Note that in this case a separate EM is required, since the EM will remain with the spacecraft until after completion of payload in-orbit commissioning as per EID-A section
14 Nov 2007 - Use of fold-outs in proposals

Does ESA have a position on the use of fold-outs? Would it be acceptable to include 2 fold-outs in addition to the 40-page A4 limit?

A: Yes, a maximum of 2 fold-outs is acceptable.
14 Nov 2007 - Instrument reference temperatures
Q: According to EID-A, section, the PI shall define the URP temperature. However, section, in the paragraph devoted to internally mounted units defines a temperature range for URP. This section also mentions the SRP temperature level, relevant only for externally mounted units (as stated in Please clarify the meaning of that paragraph and who is responsible for the definition of the URP temperature range.
A: The control of the Unit Reference Point temperature of internally-mounted units is under the responsibility of the spacecraft Thermal Control Subsystem. However, it is up to the unit supplier to define the location of the URP in accordance with definition He defines also the desired ranges at that point if they are not in agreement with the range proposed in Although the proposed temperature ranges ( are negotiable, it is important to understand than any narrower range will strain the spacecraft thermal control subsystem and therefore will count as a request for extra resources.

When a unit is mounted outside the spacecraft, it is assumed to be thermally decoupled e.g. with washers, CFRP legs from the spacecraft structure. In this case, the instrument will control by itself the temperature of the URP. Per definition in, the URP is "on the unit side close to the mechanical interface to the spacecraft". On the spacecraft side, there will be a Spacecraft Reference Point (SRP) whose temperature will be controlled by the spacecraft Thermal Control Subsystem.

14 Nov 2007 - Infrared fluxes into instruments
Q: According to EID-A, section, the infrared loads QB from the thermal baffle and reaching the inner part of the instrument through this aperture shall be computed with the temperature of the baffle, TB. The baffle shall be simulated by a perfectly black surface closing the aperture and maintained at a temperature TB. Please define the values of TB for the different load cases.
A: At this point of the accommodation studies, it appeared more robust to provide directly in the EID-A the fluxes QB themselves rather than the temperatures TB. Therefore the computations called for per section have already been performed or superseded by the table providing the fluxes, which is Table 8 in section 4.7.4, page 61. In Table 8, QB gives only the maximum solar flux entering the apertures of the respective payload units for the particular accommodation studied. This is the reason why the EID-A still contains section, but for now, since the QBs are given, the TBs should not be necessary to perform an instrument thermal analysis.
19 Nov 2007 - CMOS imager with EUV detection capability
Q: Please provide any recent update of the status of the "CMOS imager with EUV detection capability" undertaking described in section 1.6.2 of the AO.
A: This activity has been placed on hold, pending gathering of information concerning the other technological alternatives being pursued. A decision to resume this activity can only be made if a clear technical activity can be defined, and if it is clear that ESA's support is indispensable, which is not the case today. No contract has actually been initiated to-date.
22 Nov 2007 - Status of Solar Orbiter programme
Q: Please provide an update of the status of Solar Orbiter following the recent Science Programme Committee meeting.
A: Following the positive outcome of the Science Programme Committee meeting on 12-13 November, Solar Orbiter will enter its Definition Phase (Phase B1) in January 2008, leading towards mission confirmation (including Cost-at-Completion approval) by November 2009, in order to remain compatible with a launch in mid-2015. When presenting the way forward for Solar Orbiter to the SPC, the ESA Executive confirmed that the overall cost to ESA is within the allocated envelope set in order to comply with the recommendations of the Science Programme Review Team. The approach adopted is based on maximum reuse of technology developments and available units from the BepiColombo project. The Mission Operations Centre and Science Operations Centre have been scrutinized and solutions found to make them compatible with the available cost envelope. In line with the strategy to conduct Solar Orbiter as a joint scientific programme together with NASA's Solar Sentinels mission, the present baseline is that Solar Orbiter will be launched on an Atlas V provided by NASA.
23 Nov 2007 - Instrument back-up solutions in proposal
Q: During the course of the definition phase of the Solar Orbiter mission, from the very first science definition and payload definition meetings, and until the recent joint Solar Orbiter & Sentinels study, the involvement of US scientists has been significant. As a result of this involvement, many instrument LOIs for Solar Orbiter have proposed US Co-Investigators to supply essential parts of their investigations. These agreements at the instrument LOI level were motivated by the aim of proposing the best instruments possible and increasing the science return of the mission.
Following NASA's FOSO AO it appears possible that the level of NASA funding may not be able to cover all the US hardware contributions as expected during the LOI phases. As a consequence we would like to know how we should manage the back-up solutions in the proposal, in case a sub-system of our instrument is not selected by NASA.
A: The proposal should include the optimum scientific and technical solution as baseline, but clearly state the alternatives and their scientific, technical and financial impact.
23 Nov 2007 - Maintaining instrument acronym
Q: Is it possible to propose an instrument named with an acronym different from its AO designation?
A: Yes. Use of a different name or acronym will not be held against a proposer during the evaluation; however, sticking to the AO designations (or at least to something close) would avoid an acronym translation exercise and would simplify matters for the evaluation team. There are many instruments, several of them with several sensors, and we expect numerous proposals, resulting in (potentially) dozens of acronyms.
23 Nov 2007 - Co-PI rights at meetings
Q: In case a Co-PI is proposed and accepted for an instrument, does this Co-PI have the same rights as the PI during the SWT discussions on implementation, accommodation, operations?
A: As stated in the Science Management Plan, each investigation has a single interface to the Project Office, namely the Principal Investigator. Exceptionally, a Co-PI may represent the PI at SWT and other project meetings and where applicable, be eligible to vote on his/her behalf.
3 Dec 2007 - Application of ESA technology development
Q: Should the technology development undertaken by ESA mentioned in the AO be taken as baseline, backup or augmentation?
A: The technology development that has been initiated by ESA is being done for the purpose of mitigating the risk for several identified critical payload technologies. The aim is to mitigate the risk by developing at minimum a feasible backup solution. While it is not mandated that these technologies be used in the instrument proposals they may be considered as either a baseline or a backup solution.
3 Dec 2007 - APS development
Q: Will the APS development be done as an ITT?
A: All detector activities described in the AO have already been initiated with the exception of the CMOS imager (see question and answer above, Nov. 19th).
3 Dec 2007 - Cost of APS sensors
Q: Can ESA put a price on the APS sensors they intend to develop for Solar Orbiter?
A: There are several activities in progress, electro-optical characterization of the LUPA 4000 detector, proton radiation sensitivity tests on a CZT detector and development of the BOLD detector. The LUPA 4000 is commercially available and pricing information should be readily available. Pricing information for the other devices would be extremely premature at this stage, as technical feasibility has not yet been ascertained.
3 Dec 2007 - Cost of RTC chip 
Q: Can ESA put a price on the RTC chip they mention in the AO?
A: The price will be about 2-3 kEuro per unit.
3 Dec 2007 - Application of ESA developed technologies
Q: In the AO it explicitly states for the Heat Rejecting Entrance Window that "Proposers who intend to make use of this technology or a derivative, e.g. for an instrument that would benefit from a similar item with different passband wavelengths, will be expected to take over the development and procurement of the item. ESA welcomes but does not require any proposer to make use of this development." Does this only apply to this technology or does it apply to the other ESA technology development activities as well?
A: ESA makes every effort to steer the developments towards the widest use onboard Solar Orbiter if it is at all possible. However, if an instrument needs a modified version of any of the technologies being developed it will be the PI's responsibility to undertake the delta development activity.
3 Dec 2007 - Preliminary orbit parameters
Q: Are the "Preliminary Orbit Parameters" files, on the ESA website, still considered valid for payload purposes?
A: Yes.
3 Dec 2007 - Thermal diaphragm responsibility
Q: Who is responsible of the thermal diaphragm?
A: The spacecraft will provide the thermal diaphragm for the heat shield feedthrough.
3 Dec 2007 - Interface heat shield/instruments responsibility 
Q: Who is responsible for the interface between the heat shield feed through and the instruments?
A: By definition, both sides are responsible for an interface.
3 Dec 2007 - Cleanliness environment class
Q: Can we expect a better cleanliness environment (Class 100) due to instrument specific cleanliness requirements?
A: No.
3 Dec 2007 - Molecular contamination level 
Q: Is the given molecular contamination value (7×10-8g/cm²) applicable at delivery?
A: This is the level incurred in the period between delivery and launch.
3 Dec 2007 - Addressing impact of direct illumination
Q: In section of the EID-A what does "short duration" mean?
A: In the EID-A (pg. 58) it states that:
The PI shall address the consequences of:
  • Illumination from direct sunlight at 0.22 AU for short duration (15 degree off-pointing for up to 20 seconds, TBC).
The short duration is defined as 15 degree off-pointing for up to 20 seconds.
3 Dec 2007 - Spacecraft vs. instrument heat rejection
Q: Can we increase the entrance aperture if the instrument heat rejection baffle has been improved with higher rejection efficiency?
A: No. Even if the instrument's heat rejection capacity is increased it does not change the amount of heat flux that must be rejected through spacecraft resources (radiators, etc.).
3 Dec 2007 - PAD review period
Q: A minimum of 20 working days are stated to review a PAD (part approval document). Can we expect shorter review in a critical situation?
A: No. At this stage it should be considered that the review will take a minimum of 20 working days.
10 Dec 2007 - Co-PI appointment 
Q: Section 2.7.2 of the Science Management states: "Although not a preferred arrangement, in some exceptional circumstances, a Co-PI may be appointed." What kind of exceptional circumstances are meant and to what extent is this arrangement not preferred?
A: As stated in the SMP, ESA requires there to be a single management interface for each instrument, namely the Principal Investigator. In the (exceptional) case that (parts of) two investigations are merged during the selection process, a Co-PI may be appointed. Another possibility is that one Co-PI acts as Principal Investigator during the development phase, and then hands the PI-ship over to the other Co-PI after launch (i.e., during the scientific exploitation phase). A situation in which there are more than 2 Co-PIs, each with equal rights, is not acceptable. In this case, the PI should designate a number of "Lead Co-Is" within her/his team.
13 Dec 2007 - On-board data storage
Q: Does the spacecraft provide data storage? (How many Gbytes) Is this mass-storage randomly accessible? (i.e. once we have written data in it, can we go back to these data and alter them?)
A: The spacecraft is designed with on-board memory to store telemetry received from the payload. Once the payload telemetry is stored on the spacecraft on-board memory, the payload cannot alter or access the content of it, except possibly to change the assigned priority as described in the next question.
13 Dec 2007 - Telemetry handling
Q: How will the telemetry queue in the spacecraft be handled? Would it be possible to selectively download through telemetry only certain sections of this onboard storage? (example: “please send us HRI images of Nov 11 2018 between 9:00 and 15:00, but delete all other images of the same day?)
A: At minimum, it is currently planned that during the long residence time periods the data in mass-storage will be assigned a priority that would determine the order in which it would be downloaded. It may be possible to change this priority while the data resides in the spacecraft mass memory.
13 Dec 2007 - Pointing stability and jitter
Q: Is pointing stability of 1-arcsec over 10-seconds still to be considered as baseline?
A: The pointing performance can be found in the EID-A, Table 6 (page 46).

Q: What is the expected jitter spectrum from few 10Hz to few minutes?
A: Information is not available.
13 Dec 2007 - Composition of platform structure
Q: What is the platform structure made of (honeycomb panel with aluminium or CFRP face sheets)?
A: This can not be specified at this time.
13 Dec 2007 - Thermal specifications
Q: What does “hot/cold interfaces” mean, i.e. which temperature?
A: The temperature is determined by the needs of the instrument. The cold finger is below the reference temperature of the instrument, while a hot element interface has a temperature above the instrument reference temperature.

Q: Where is the interface located? (between radiator and cold finger?)
A: The hot element or cold finger is considered to be the interface.

Q: The instrument may also need a hot element interface for heat rejection of its entrances baffles. May we count on 2 radiators? Is it acceptable to have more than 1 interface between the instrument and the hot elements radiator, and between the instrument and the cold finger radiator?
A: It may be possible to provide more than 1 hot/cold interface to an instrument. The number of radiators, however, depends on the spacecraft design.

Q: Are the radiators dedicated per instrument or shared with other instruments?
A: This is dependent upon the spacecraft design; however instruments may have either dedicated or shared radiators. It may be necessary for dedicated radiators to be provided by the instrument.

Q: Is it correct to assume average temperatures of 200°C (cold case) and 350°C (hot case) for the heat shield baffles?
A: The hot case can be assumed as 350°C. The cold case can be assumed as -120°C for a worst case of a closed baffle (a baffle that is open on one or two of the four sides would reach colder temperatures).

Q: Has the spacecraft taken into account any reflected flux coming from the instrument toward the heat shield internal baffle?
A: Yes, in general this was considered. However, a typical baffle was assumed and it was not designed in detail.
13 Dec 2007 - Interface of heat shield/instrument front face
Q: What is the expected gap between the Heat Shield and the instrument front face? May we expect a protective door in-between?
A: The detailed interface between the Heat Shield/baffle and the instrument front face is currently being defined. It will be designed to be light tight to prevent straylight entering the instrument aperture. The instruments can not expect a protective door between the HS and the instrument aperture. As described in the EID-A section, a door may be placed on the Sun entrance end of the Heat Shield if required. If a second door at aperture level is necessary (i.e. for contamination protection purposes) it shall be provided by the instrument.
13 Dec 2007 - Instrument external radiators
Q: Who provides the instrument external radiators?
A: In general, if an instrument is internally accommodated it is assumed that the spacecraft will provide a radiator. However, the instrument team may be responsible for providing a dedicated radiator if it is required.
If the instrument is externally accommodated it will be fully responsible for its own radiators.
13 Dec 2007 - Launcher authority safety requirements
Q: In the EID-A section 7, “Launcher Authority Safety Requirements” is mentioned. Can we have this document?
A: This will be provided once the launch vehicle is fully specified.
13 Dec 2007 - Document templates
Q: For a number of previous ESA missions, e.g. BepiColombo, templates were provided by the project for the Engineering, Management and Product Assurance plans (such as NCR, RFW, EEE, MIP/KIP, DML,&), is the project planning to provide such templates?
A: Templates will be provided to selected instruments.
13 Dec 2007 - Date and purpose of ISRR
Q: An Instrument Science Requirements Review (ISRR) is planned to be held 7 years before launch, i.e. in May 2008. This is falling some months ahead the payload selection (Q4 2008) and would not allow the conduct of a proper Phase A. Please re-plan the ISRR. Is the ISRR still planned 7 years before launch (2015)?
A: The ISRR is still planned to be held 7 years before launch. Its purpose is to settle the baseline performance of the instrument as selected. In the simplest case where the proposal was sufficiently detailed and complete, it is simply a formalization and confirmation of the instrument baseline performance as proposed. If some clarification or more detailed work on the baseline performance was needed and performed during or immediately following the selection process, then the set of baseline performance requirements finally agreed upon at the outcome of selection and worked out to the necessary level of detail is to be frozen by the ISRR. This also includes making sure that there is an agreed baseline in case the proposal contained several options for performance and/or design concepts. Since the acronym ISRR appears to be a source of confusion, we will replace it with IBPR (Instrument Baseline Performance Review), or something similarly more to the point.
13 Dec 2007 - Spacecraft pointing methods
Q: If the spacecraft is to point at a fixed location on the Sun during the remote sensing science windows, the spacecraft will have to account for the rotation of the Sun (even at perihelion as true co-rotation will not be achieved). How will the correction be done to maintain pointing at a fixed location? Will it be smooth or in steps? Using reaction wheels or thrusters?
A: The spacecraft pointing is almost always performed with the reaction wheels, thrusters are only used if absolutely required. Reaction wheels can be operated in continuous mode so that the spacecraft pointing can be adjusted smoothly.
13 Dec 2007 - Product Assurance and Management Plans
Q: The EID-B contains section 7, Product Assurance Plan and section 8, Management Plan. In addition, the proposal is required to contain part IV, Product Assurance Plan and part V, Management Plan. What is the expected relationship between the content in these two parts and that in the EID-B?
A: The Product Assurance Plan and Management Plans are indeed expected to be part of the proposal. In the draft EID-B the respective plans can be referenced, however they should cover, at a minimum, all aspects outlined in the EID-A.
13 Dec 2007 -  Question on Letters of Committment / Endorsement by funding agencies
Q: The last part of the answer to the question dated 12th November states: "Because of the respective AO schedules, U.S. proposers are required to provide within their proposal to ESA a NASA document certifying that their proposal has been received and accepted by NASA and declared compliant with the SMEX/FOSO rules. (Other proposers are required to include a full-fledged Letter of Commitment from their funding agency.)"
How does this apply to US contributions to an European-led proposal which will also seek funding through FOSO? Obtaining a NASA letter of endorsement implies submission of the proposal to NASA for compliance checking several weeks ahead of the ESA deadline, while the stated FOSO deadline is actually not until 2 weeks after the ESA deadline. Under these circumstances, does ESA expect a NASA endorsement to come with the proposal to ESA?
A: Considering the tight AO schedule, the recent updates to the ESA Science Management Plan and the difficulties in forming instrument consortia with final and binding agreements at this stage between envisaged hardware providers, ESA will accept Letters of Endorsement if it is not possible to provide Letters of Commitment at the time of submitting a proposal. These Letters of Endorsement must, however, include a timeline of decision points within the relevant funding agency, leading to a final commitment to join the proposed instrument consortium. In the case of Letters of Endorsement from NASA, these should be submitted separately as an addendum to the proposal as soon as possible after the FOSO deadline.
14 Dec 2007 -  Instrument Manager, references in AO documents
Q: In the AO it is mentioned (pg. 3) that the "PI shall nominate an Experiment Manager"; on page 14 it is written that the management scheme "must include an Instrument Development Manager; on page 16 it is written that the Funding Agency have "responsibility through the PI and Instrument Manager". In EID-A sometimes it is termed an "Instrument Manager", and others an "Instrument Development Manager". Is it correct to assume that all of these different names are for the same person, having the role of "Instrument Manager"?
A: Yes, all of these references do refer to a single position, the Instrument Manager.
14 Dec 2007 - Spacecraft off-pointing procedure
Q: For some instruments (such as a coronagraph) it might be necessary to include internal mechanisms to compensate with spacecraft off-pointing. The complexity of these mechanisms however depends on the way in which the S/C will realize the off-pointing. In fact there are two ways to off-point the S/C, let's say to North-East: either an off-point to North followed by an off-point to East (or viceversa), or a S/C 45° rotation around the Sun center boresight direction followed by an off-point.
If the "total" off-point is realized in the first way, the instrument would need to move its components along two directions, to compensate the two S/C movements; however, if the off-point is realized in the second way, since the S/C rotation is not affecting the instrument alignment, the instrument would only need to move its components in a single direction. This would greatly simplify the mechanisms, with a significant mass saving, a reduced mechanism complexity and additional safety. Would this off-pointing strategy be feasible from a spacecraft point of view?
A: The procedure for off-pointing has not been firmly established at this point, however a manoeuvre such as the one described in the second option is not currently being contemplated. This is due to the fact that the orientation of the in-situ instruments with respect to the velocity direction must be maintained (i.e. y-axis parallel to the orbital plane).
21 Dec 2007 - Instrument description, number of pages
  1. On page 8 of the AO all the content of the cover page is described. It seems hard to fit it all to one page unless one uses a very small font size. Can the cover page be extended or the funding agencies and CoIs names, addresses, telephone etc be put in the management plan?

  2. On page 7 of the EID-B (part II), are the page limits strict or could they be extended? 20 pages for chapter I (general introduction) seems a lot while 10 pages for chapter 3 (instrument description) is probably not enough.
  1. It is acceptable to put the details of the funding agencies and Co-Is in the management plan.

  2. It is acceptable to exceed the number of pages in chapter 3 if the total number of pages of chapter 1 and chapter 3 remains 30.

11 Jan 2008 -  Deadline paper copies and endorsement letters
Corrected 15 Jan 2008

Q: Can ESA accept receiving the paper copies of an instrument proposal later than the 15 January 2008 deadline?  To take into account the extra time involved in obtaining letters of endorsement from our funding agencies, can ESA accept receiving them later than the proposal itself ?
  • As long as the proposal is made available in electronic form on the proposer's FTP server (or sent by email if the proposal is small enough) by the stated deadline of 15 January 2008 24:00 CET, ESA will accept receiving the paper copies no later than 17 January 2008 close of business.
  • ESA will accept the required funding agency letters of endorsement until 08 February 2008.
25 Jan 2008 - Submission deadline U.S.-led proposals
Q: Is it still possible for U.S.-led proposals to be submitted to ESA?
A: In order to accommodate the NASA FOSO process, the deadline for receipt of U.S.-led proposals by ESA has been extended to 24:00 Central European Time on Wednesday 06 February 2008.

Last Update: 1 September 2019
24-Jan-2022 07:21 UT

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