Meeting Minutes - OST STDT Bi-Weekly Telecon - May 4, 2018


Subject:OST STDT Bi-Weekly TeleconDate:5/4/2018
Purpose:To discuss science activities for OST.Facilitator:Asantha Cooray/Margaret Meixner
Location/Time:

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Meeting number: 628 543 585

Audio Connection: +1-510-338-9438 US TOLL

Note Taker:Sydney Jones



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Discussion Items 

News, updates (May meetings…), science meetings

  • OSS is in IDL this week
  • F2F #8 is less than two weeks away. This F2F will be used for:
    • Discussing what will happen during summer science meetings
    • Margaret Meixner recieved an email from Kate Sue summarizing that the protoplanetary disk group does not plan to meet over the summer. Klaus Pontoppidan concurred. The proptoplanetary disk science group must make submit all required deliverables as expected on schedule to the management team . 
    • ACTION: Draft and send out table of contents for final report to discuss and flesh out, and discuss and develop a schedule of when we need things over the summer and fall of 2018.
    • Margaret Meixner has spoken to Cara Battersby and @Karen (last name?) about scheduling a summer science meeting for near by galaxies and milky ways
    • The exoplanet science group will be meeting as planned over the summer  
      • Kevin Stevenson mentioned that the exoplanet group is looking at hosting a workshop or splinter meeting at the winter AAS in 2019
      • Kevin Stevenson will keep Gary Melnick informed of details regarding the proposed exoplanet working group winter AAS workshop/splinter meeting 
  • Proposals for special sessions at the winter 2019 AAS meeting are due by . AAS wants to see real science results discussed. 
    • Deadline for input to final report for Concept 2 is due by the end of summer 2018.
    • Gary Melnick added that purpose for workshops at the winter 2019 AAS meeting is to communicate information from our team to the community, as opposed to accepting additional information from the community into the final report. Margaret Meixner concurred.
  • There will be about 10 presentations related to OST at the June 2019 EPIA meeting in Austin, TX. Margaret Meixner has asked presenters to draft an outline and to discuss coordination at the 8th F2F. 
  • Thomas L. Roellig asked about potential delays to the Decadal review. Margaret Meixner added that NASA has an interest in delaying in due to JWST delays, but NSF and DoD do not want to delay this. OST has been given no direction to extend the study, and will be operating on schedule.

Mission Operations Concept - Meixner 

  • This topic will be discussed at the 8th F2F
  • Summer exercise is a design reference mission spreadsheet. Margaret Meixner thanked those who have responded and commented on the spreadsheet.
  • Mission operations concept has to do with observatory wide missions operations concept stuff. There is a policy side to this (GTO vs. GO for example).
  • In thinking about the instrument suite and how the observatory should move, how does STDT envision using Concept 2? Are there specific parallel operations that you think are useful to have, or survey areas (speed, mapping, stability). Things that haven't been defined so much. The purpose of this discussion is for the engineers to get feedback and to shape the design reference mission study. Mission design lab activities will occur for fleshing out attitude control (1st week in August), so when are determinations made for the following questions (some requirements have already been determined and sent in).
    • Response to this question included the following:
      • Nervous about how quickly to turnaround in making a map. There are those who want to go deep in small field, and those who want to look at wide areas. Making the observatory efficient for looking at a degree or half a degree is very important for nearby star formation (mapping around a square degree). Lack of efficiency for a degree scale will be problematic for nearby star formation and nearby galaxies. 
      • Do you see a significant difference with mapping imaging in terms of efficiency? Bright variables should be mapped, but the area should be considered. With pointed, the question is how sloppy is the telescope and how quickly can it integrate. 
      • Pointing observations (for spectroscopy), but we will be using the fine steering mirror with a wide grasp (parking the telescope). Can the fine steering mirror be moved in order to get the map?
      • How do you define what is settled, is it a fraction of a beam and what would the fraction be? It depends on the science case. You want stability needed to do spectroscapy thats desired. This is a science dependent thing. A fraction of a beam is typically settled better than a tenth of a beam. 
        • What would this be for exoplanet transits? Strong function of how stable your instrument is, relative to intrapixel variation. Ideally, if you have intrapixel variations that are systematic and need to removed, then you would want no motion at all so the systematics is kept the same for any given observation, however this is not realistic, so one should minimize it as small as possible. Will defocusing be done for exoplanet observation (this will allow for more robust intrapixel variation and jitter). It is naturally defocused because its diffraction limited at 30 microns. The spectrometer design divides up the pupil. What Sean is saying is true, but is different for other missions.
        • Diffraction limit can be adjusted in our spectrometer because OST has a deformable mirror. OST has put together a set of pointing and imaging requirements for transit spectroscopy. 
        • For pointed spectroscopic observations, clusters of young stars, if doing parallel imaging, OST may be able to cover a significant fraction of the cloud.
          • When on a source, is there a jitter pattern? Have not gotten this far. Will not do deep extragalatic imaging in regions with young stars because background will be high. Long integrations are not necessarily done, these are many points of spectroscopic integrations of clusters with one square degree. 
          • ACTION: Specify how would you get a good image if you do spectroscopy for a long time? 
            • Can't see how you would move for one instrument and not for the other. 
              • Imagers have an instantaneous field of view. MISC imaging can be done in parallel if doing spectrocapy on a pointing source (there will be offset somewhere), offset sources in the cluster may still have good coverage of paralell region. 
          • Serendipitous pointing is not a mode that will justify the science case. Science case justification has to be something that is directed at a combined image. Herschel surveys had hax and spire in parallel and they all used this mode. If experts can develop this science case, this seems to be the mode where.
            • Any idea of what instrument offsets look like (ACTION: It would be good to communicate this with the design reference mission spreadsheet so people can think about this)? Relatively small, 20 arch minutes at most. 
            • Is it interesting to have OSS and FIP in parallel? Is it important to have this in parallel or not?
              • Will be useful to have parallel for extragalatic  
              • FIP and OSS would have to scan at the same rate.
              • May be useful for small body survey
            • Are any modes running into data rate limits, because for parallel this would be the bottle neck? This may be one of them. This gets revisited at the mission development lab, as each instrument will have its own data processing and maybe a memory buffer. They send all of this to a solid state recorder. They are sizing things at the moment. Determinations for this will be made in August 2018. 
            • Although everything may not be ran in parallel, but there is a strong science motivation for this, considering the OST mission will be judged on science value per dollar. From the design reference mission, we can talk about how much data will be accomplished from these surveys. 
          • Responses included mostly MISC and FIP, OSS and FIP (etalon in parallel with imaging, may need to be fleshed out) and possibly some spectroscopy.
  • Status of instrument parameter feedback submissions to David Leisawitz

Outreach projects – Battersby & Kataria

  • No notes for this item.

F2F Meeting Discussion

  • Possibly add explanation as to why cooling is not a major issue. Margaret Meixner will discuss this with Ruth Carter
  • Polarization can be used for the GO program. 
  • Bring cyrogenics ideas or theories to 8th F2F

Study Center update 

  • Will add this later...