Meeting Minutes - Interim Report Review - November 17, 2017


Origins Space Telescope (OST)

Interim Report Review 


Purpose: To review and evaluate the OST interim report.Facilitator/Host:

Margaret Mexiner/ Spitzer Science Center

Goddard Space Flight Center (GSFC), Greenbelt, Maryland


Telecon: WebEx Online

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Meeting Number:

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Access Code: 900 952 539 
Meeting Password: telescope

Scribe:Sydney Jones

Discussion Topics 

Introduction - 9:00 AM - 9:15 AM

  • General Interim Report Open Discussion 
    • Overall purpose is to walk through the proposal, discuss input from the review panel, review individual sections and overall perspective.
    • Sheth: In reviewing interim report, did the review team envision themselves as a decadal member?
    • Mather: In some ways yes.
    • Warner: Added that we tried to remember that we are talking about year 2035. It is important to imagine ourselves in this era. 
    • Reiki: One should think of 2019 as the era.
    • Leisawitz: Intention is to think about uniqueness and special capabilities in the 2030s. 
    • Proposing technologies are less than or equal to 2032. Technologies are at TRL-5 by 2024, which would satisfy the decadal survey. The more technologies OST has at a high level the better. 
    • Consensus is that we have a dual role. Science should be compelling in the 2035 time frame. These questions may not be answered between now and then. Reasonable belief should be that technologies should be available by then.
    • Reiki: Will we get a response back (presumably from the decadal review)? Susan has had conversations with the study managers. Leadership is very keen on understanding what we have to say. Looking for feedback on the interim report itself and feedback on the interim report and final report. Content included in the interim report is outside the box and may be overachieving. Need to make some hard choices going froward, cost wise, that are compelling for a decadal recommendation. 
    • Leisawitz: This and other concept studies are community led efforts. The NASA Center (Goddard Space Flight Center (GSFC)) are largely responsive to community driven requests that drive the concept and do two things for the decadal; present mission concepts that are scientifically compelling and executable. We are going through two different design cycles - Concept 1 (interim report currently) and Concept 2. Concept 2 is less ambitions that Concept 1. We approached it in a cost unconstrained way that is very large in size and cost. This may be a problem. We have been in contact with aerospace all along, and understand what the CATE will do. Concept 1 is very large - we are deliberately looking at something smaller. Telescope collecting area for Concept 2 will be 5 meters in diameter. The telescope diameter for Concept 2 will be 9.1 meters (hexagon). 
    • Sheth: Science should be compelling. Community peers should agree that the mission is worth doing. If science is definable, NASA will support it. Given budget realities with Spitzer, we can adjust the scope accordingly, but the mission can still be compelling. 
    • Reiki: Are we willing to be canceled six times?
    • Sheth responded that we would like to avoid this. The number OST would like to be at is $3 Billion (B). It's up to the team in terms of what they want, but the science should be compelling. 
    • We have purposely allowed time to incorporate review team comments.
    • Reiki: Discussion with review/panel team should be flagged to discuss with the team (STDT). 
    • Susan sent out a spreadsheet that provides the opportunity to do what Reiki is saying in terms of providing feedback. She asks that reviewers take time after the meeting to fill in the charts (on the spreadsheet sent out) for any area that needs to be presented to the team. Panel members are not expected to review the report before it goes to HQ. We may be invited back to look at or provide comments for the final report.
    • Leisawitz: Interim report will be thinned down. 
    • What is the audience for current version? Comprehensive summary gathered from the team. An archive of what we have done in Concept 1 study.
    • Mexiner: Audience is the decadal committee and astronomy community. 
    • Review report by two or three science members with decal science experience. The interim report committee will have some decadal review experience, but they will not go into detail unless the report is vastly off track.
    • Sheth added that the report will be published on a site where all decal report material is already posted. Susan added that OST should view what is put out as something that could be viewed by ASTRO PR and added that OST does not want to put something out that puts them in a bad position. 
    • Should have strong technology and detector road map. Extract road map and have a very well worked out mission implementation, in showing we are on the right path. 

Executive Summary - 9:15 AM - 9:45 AM

  • Questions for the Interim Report (reviewers should take advantage of using the spreadsheet to feed additional comments to the team).
    • Does the report make a compelling science case and is theh mission executable (technology roadmaps)?
    • Is the deisgn self consistent?
    • Will mission parameters lead to propsed science?
    • Is the report organized logically? (HQ does want to look at this to see that report holds together so the public (and those examining it) will not get lost in a bad construct of reprot. 
    • Recommendations for interim report and final report (for Concept 2)?
  • Additional Input from Reviewers
    • For instrument design maturity in terms of mechanics and from a mechanical structural standpoint, the panel would like to understand that we have an idea of how the concept will work, we indicate rational behind this. Identify mechanics intergated modeling and distortion (identify how we will address this). Include something that describes how to approach large integrated modeling issues, not necessarily solve them but describe them.
    • Interim report does not address worries such as testing in the beginning. Need to include that what we can do, the strategy, and a sketch of the plan as to how it can be done (include all this in the executive summary). Missing the biggest part of the picture which is the begnning. 
    • Scope of mission vs. cost is hard to swallow. Delineate how/why its easier to use longer wavelengths. 
    • Susan: Alot of what has been discussed really needs to go into play.
    • Does the report make a compelling science case and is the mission executable (technology roadmaps)?
    • Reiki: Not very well. Need a pararaph or two that has more about science cases before getting into the tools. 
    • Warner: Same comment as Reiki.
    • Executive summary does not reflect science summary in Section 3. Didn't see parrrellelism in Section 3. Including lines as intergral part would help. We are all seeing the same.
    • Susan: Did not understand how we got from three questions to how science observations would connect. 
    • Do we need science requirements flowdown implying science instruments are x and y? Do not have this anywhere. 
    • Include statement that we will do things that no one has ever done, that in 50 years these questions may not be answered. We cant claim what isnt true. 
    • Is there science that can only be done with long wave observations?
      • Very hard to tell. Went to panel for exoplanets. Everything discussed in the panel has been done, but in very different ways. 
      • Primordial H2, for biosigntatures, get methane together with Ozone, need Mid-IR and need to explain multiple observatories and combining forces and what this would be able to do. 
      • Reiki: Doesnt think we can do a good job of doing this going forward. H2 is possible, but we have to do our best.
      • Jean: Great wavelength band. She would like everything she saw to be done (saw great stuff). SOPHIA may be able to, but this could potentially do it. H2 is fundamental, and studying gas in the early universe. Broadly speaking this is where the team could go with this. Galaxies: key lines in interstellar medium (traces kinematics of the gas) cooling lines and intensity, but kinematics are important. Too much imformation there (in section about galaxies) it is hard to pasrse through.
    • Does executive summary convey executable mission?
      • The exective summary does not address this. 
      • Executability is helpful to capture in the executive summary. 
      • Not much in executive summary but science. 
      • If we dont take the chance to say that this could be done then we have lost. 
      • Hardest one is detectors and deep cooling (need to say there is a possilble plan).
      • Thompson: Questioning executability of Concept 1. Numerous comments about there being no thought to cost or scheudle, only to science, needs to be fleshed out.
      • Reiki: Concept 2 (being a 5 meter telescope) need to comment on things that we may be very careful about doing, for Concept 2. 
    • Is the report self-consistent and does the report lead to measurements? 
      • How are they related to instruments (the five instruments stated here)?
      • Include traceability matrix, show what instruments attack certain themes. 
      • Graphic may be helpful. Draw things that say heres a particular phenominon and link to instrument.
      • This report makes a big deal about covering huge areas of the sky. OST field of view is similar is JWST? Thinks this is compleletly unbelievable. Margaret spoke with those in the lab, Eric Stoneking said motion mechanisms for OST are different than JWST. The interim report will need to better clarify this. 
        • Fast is not the only requirement for detectors. 
        • Is the fast steering mirrior able to do this (cover huge areas of the sky)?
        • Need a section dedicated to covering huge areas of the sky. Need to know where the detector is pointing. OST is more about reconstructing the map after (where it was pointed for remapping). OST dectors are continuously moving. 
        • Need to add that we can observe as we are scanning. 
        • Warner: Use a design reference mission. What are design reference missions and see if this all works. Continuous scanning doesnt allow us to go deep (spectroscapy). 
      • Discussion for report organization will come as we move further along. 
      • Section 2: Make sure lessons learned feeds into argument about executability.

Science Investigation (Part 1) - 9:45 AM - 10:30 AM

  • NOTE: Susan pulled major subtitles out of report (major themes) (discussions about compelling, executability and organization)
  • Panel Feedback for Science Themes 
    • Tracing the Ingredients of Life and of Habitable Worlds 
      • Reiki: Had trouble with section because capabitlies kept popping up. Tracability matrix should be included to show how the themes tie into the science capabilities. Otherwise it detracts from the science. 
      • Should we incoprtate this into the exetcutive summary? Need to have overview of capabilties 
      • Reiki: Map the rule of three into the executive summary. Tracing...could be subnotes...included into the exectuive summary. Organize these four themes into the three questisons. Put questions in executive summary as a header. 
    • OST Reveals the Physics of Star Formation and Black Hole Growth  
      • Jane:  Apply the rule of three
    • Charting the Rise of Metals, Dust, and the First Galaxies
      • Jean:  Apply the rule of three
    • The Solar System in Context 
      • Doesnt understand division/separation (formatting), lots of lines, hard to organize. Doesn't understand why they are separated. Organization is key.
      • Context is clear
      • Warner: Move solar system up to habitable worlds sections. Secondly, in talking about satr formation, should talk about star and planet formation because they are so intimately linked. Global star formation is the difference. WIthin our galaxy we should keep a couple.
      • Susan: Had trouble establishing a connection. Was not able to tell how it pulled together as a mission, as opposed to things that scientists want to do. How does this lead to mission suite, and mission parameters.
      • Cooray: May be missing mission implementation section. 
      • Mexiner: Should provide a better roadmap in the beginning. 
    • Comments for individual science investgations
      • Reiki: Page 14. Did not have positive reaction to simulated planetary trasit. gain in JWST is using same detector type, telescope (factor of twenty). Report says we will order up detectors that are more stable. Thinks this is insulting. JWST has the best detectors. 
        • In report, spell out what we have (densified pupil). OST is meeting with infra-red detector specialists.
          • JWST is limited in detector capabiltity, not sure if what is recommended will help.
          • Need to discuss with panel. 
          • Warner: Part of proposal is badly oversold. Mention in figure caps that we will have better detectors. Moved trapis star in too close. In competative environment, starting in very first sentence (habitable worlds..) will have coronograph people at our throuats before they get to page two. This part extends beyond the imagine (habitable worlds and detectors). May be other things that will come in for next deacde of performance (proton detectors). He is refferring to pages 13 - 15. 
      • Jeane: Concerns about the lines, and focus on HD and measuring mass (Gas masses). Unless there is something she doesnt know. Not super correlated with H2. HD, fractionation and chemical abundance and exotation temperature (128 degrees). ALMA (really bright Co2). This has exotation (128 degrees). Bright where there is hot gas. In terms of measuring mass, there is a problem. Bright C02 is coming from very little gas. HD is good for somethings, but it shows up a lot and needs to be dialed back and explained why it is. 
        • Weidner: HD expert (proposed discussuion with Jean to follow up on). 
      • Rikci: Mike, Jean and I are saying some of the same things.May have made a mistake by loading so many different science themes. Distill down to two or three great things (for the themes) and focus on those things. Well explained and detailed enough. View us as a panel (decadal survey) where the knives really slice. These are very keen to the science case. Modification that these are mapped into the different science themes. Things that we can do with telescope that cant be done with any other telescope. 
      • Warner: Isotomically substitute species. Conversion factor is measuring line width. Isotpoes, cold temperatures are subject to fractionation, and running into chemical problems.
      • Susan: Sense of showing magintude of science loosing what is most interesting and unique to this type of measurement (interstellar medium exploration is particularly compelling in the interstellar medium)
        • Jean: Complicated. Lot of lines. Learned alot from Herchshel, CO sled (certainly worth referring to). 
        • RIcki: So much infra red detail. Pick key points and drive those home. 
        • Warner: More of a problem in the extragalactic section. 
      • Tracing the ingrediencts of life and of habitable worlds...
        • How does it interellate with other questions? GOing back to original questions and identifying linkage between them. 
        • Warner: Dont make much of spacial resolution in OST. Nearby galaxies have an additional advantage. Big advantage over Hershel and SOPHIA. 
        • Ricki: Less complexity fewer instruments in getting a lower aperature. Angular resolution is critical in getting to far-infra red. 
        • Dipirro: Wriiten comments would be very helpful (spectral confusion). 
        • Jean: Spectral confusuion, spectral resolution is very useful for line widths. 
        • Cant use red shift to solve the line issue. Incoherent spectrometers with high resolution (distingushes this mission). 
        • If you are looking at a line coming from a highly excited gas ;like H2, exotation may pick out small reigion for you in the beam. 
        • Ricki: This report relies on spectral reoluition to desconfuse things (the argument can be made but Riki rejects it)
          • Simulation......foreign concept to most astronmeers. Big burden of proof that this will work. What do we need to know to convience the decadal survey and public. Fundamental issue, making aperature smaller. Astronomers are used to pointing and extracting. A different apporach will be hard to accept (in terms of astronomers).
        • Rikci: Have to be careful not to oversell (angular resolution). 
      • OST Reveals...
        • Confused about the organization of the association of (black hole growth). 
        • Warner: Z greater than five is exactly what we want to be doing (Page 5). Talking about what ALMA, JWST wont do. Need to adopt a different perspective for 2035 timeframe, JWST & ALMA will define interesting questions, and OST will build on this progress. Refrain from the approach of saying what JWST and ALMA wont do. 
        • Susan: Should argue that OST is building on other missions. Sense of finality and didnt reflect the hertiage in a positive light.
        • Assume context (JWST, ALMA) and OST builfing on this, would shift the focus and carry the hertiage. 
        • Riki: Issues with page 23, solar metalicity number is wrong. AH features go down 20 percent of solar metaliicity. Need to be more cercumspect in showinig a simulation. Whole area is obvilious, blanket critisism of the whole area. A simulation will not solve. Pick the strong ones, dont try to justify no matter how marginal it is. Need to describe more of what we have now. There are statements of looking at AH feature for the birth of galaxies which will not work. They require carbon (generated in moderate mass stars) will not get the first thing. Emission line spectrum: should not project the z of 12 for this. Very massive galaxies have a high red-shift. 
        • Jane: Organizational problem with moving from first dusts, to dawn of...was very jarring. This has been corrected. 
    • Charting the Rise of Metals...
      • Going farther back in time, declining metal level, lines claiming to detect may not be decatable, which questions upper limitit. May not be useful circinus galxaxy for example of low metal system. 
    • The solar system...
      • Reorder it. 
      • Connection to exosolar planetary system (arguement can be made a lot stronger). Dadiacle dusts are all multiple (Figure 3.42). Hoar in on connection between solar system and exoplaneatry system. 
      • Jean: clearer and earier to read. To sell a mission you have to assume that major results come easily, need some margin.  
      • Keiper belt survey number (8000 hours). Reaction is that if it only takes a year, this should not be approved. This undermines the sientific power. Finds this to be modest. 
        • Jean: Finds this interesting.
        • Mexiner: Design reference mission may be a good discipliine, arguing what you can do and how it can be done. 

Science Instruments (Part 1) - 11:30 AM - 12:15 PM

  • Mid-Ir Coronograph (MISC) (10 to the minus 5, MISC team will build to 10 to the minus 7)
    • Which instrument drives telescope design the most?
      • Mid-IR coronograph drives the system. 
    • Ricki: Drives the wavefront error. 
    • BAseline is not to drive the coronograph. 
    • This is not considered a high priority science goal. 
    • Susan: Lee Fineberg: Mentioned that he is not a scientist, but is worried about how useful the coronograph is. Can it justify cost over complexity for lambda over D. 
    • Ricki: Lamba over D for this concept is smaller. There is an issue with descope and whether the coronagraph really accomplishes anything. 
    • In thinking about science in the 2030s,  how important is having the coronoagraph? How does this feed into habitable
      • Shielding inner worlds, detecting exoplanets (self luminous). 
      • Planets are young. A planet at 10 au is not that different at 2 au. 
      • Klaus: Science case for coronograph is detecting solarsystem jupiters, can get jupiters at 5 au, which fundamentally distinguishing it. 
      • Ricki: Competiion hasnt been defined. Example of science objective where we are bound to run into critiscm (EELT). Those telescopes are also oversold. Who can sell the most. 
      • Question of what wavelength we want. It goes pretty long. Have to the point on achieving science goals unqiquely, not just want we can do with OST. If this is important it will happen sooner. 
      • Have to make the point that this will be better than JWST. 
    • Baselining animonmy silicon waivers (hard to get these). Change to phosphorous (animony will be a huge a technical risk)
    • No one has made phosphorus detectiors. Sciences objectives at 34 microns with phosphorus (is more feasible). 
    • Effects science justification and how OST will optimize instruments (33 microns may be better). 
    • This is more about spectroscapy than measuring the temperature. 
    • Ricki: Imaging sensitivity numbers are more optimistic than JWST, which underimines the credibility of what we are claiming. JWST numbers are higher by a factor of 2. Senistivty is being exaggerated. 
      • Exaggeration is overall but more specific to the mid-IR
    • Point of clarification MISC and MISCS is a typo
    • Mechanical design comment about silicone carbide using mass or alumnimum (stability and mass). 
    • Main motivation is the biosignature case. Should we try to get NHC methane together with the Ozone. Should methane be used as a driver for the science case?
      • Extended this from far-IR mission to five and half microns. Do we have a case and can we do better than miri? No one in JWST community thinks we can do methane. 
      • RIcki: Should look at nearcam look at 3 1/2 mcrions, fundamental absorption band there, can be done from ground. From the ground, there are issues with stability. Dont focus on 6 microns and longer, focus on 3 1/2 microns (very competitive way to look for methane) 
      • Mexiner: Transit spectral channel (comments on transit)? No comments. 
  • Medium Resolution Survey Spectrograph (MRSS)
    • What is OST accomplishing with MRSS?
      • Bradford: Envisioned as general purpose wideband survey spectrometer, covers full band, between 30 mictrons and 670 microns. Optimized for sensitivity. 6 spectrometers cover this band, each with 100 beams. Designed for follow up of invidvidual surfaces, Addresses extragalactic cases. In addition to high res capability (obtain spectra), comes with no penalty in the line sense. Allows us to pull low equivalent lines using HD. Fairly simple instrument in concept. Key is the new detectors (far-IR) big thrust for OST, in understadning how to array detectors and what the focal plane would look like, and is a driver for instrument size. Pitch is (670 microns), sets size for arrays and optics are built on this).
    • general impression of MRSS insrtument?
      • Ricki: Field of view of instrument is really small, applied interation (a few seconds per point). Is questioning numbers for (200 sq degrees). Need to review the numbers for MRSS instrument and field of view.
        • Is there enough information given for sensitivity and nesessary intergrations to reproduce the number. Include this in an appendix or table. Summarize in the executive summary.
        • Need to show that this is how we get to the observation and that this is how we do it.
        • Figure 4.2.1 has information in it that will not work.
      • Mexiner: Question for Jean, is MRSS applicable to science? Are galaxies and high-resolution apart of the science case, Jean did not see it in the respective section in the report. 
    • Figure 14.2.13 looks scary. Packaging should be moutable and packagable. Ask optical engineer to run sensitivities for optical performace. Questioning sensitivities and packaging. Where do optical benches go?
      • Ricki: Instruments will have to look similar for Conept 2. Concept 2 will have to make things look less challenging. Need to point to architecture that already works for packaging. 
      • What presentation can be made to the decadal for the MRSS? 
      • Packaging is always a risk, especially if they is a sensitvity problem. Optical designer has to include sufficience margining around the optics to make this possible. 
      • There is an estimate for every single componet. 
      • There is no mechanical or structural analysis. There is not a lot of lightweighting either. The reality is that we can't create a high fidelity design. Now we are looking at smaller systems for Concept 2. Explain how we came up with this. 
      • No MRSS IDL runs have been done. Team X ran MRSS IDL run. 
    • Mexiner: Limited resources in fleshing out details. What is convincing enough to show that it is executable? Things will be heavier than we expect. What is reasonable and how to we pitch it so we understand?
      • CATE study is the enemy. If this looks complicated to an optical engineer, high risk options will cost more. For concept 2, do things with optical design that will be feasible. 
      • Looking at rays that are so close together, there is no room for baffle (red flag). Describe heritage from design fro inferometer for packaing and mass (same for spectroeters and mass).
      • John: Say that requirments don't conflict because of x. Have strategies for those things that may not fit. 
      • Figure 10 looks doable, however figure 12 does not look doable. 
      • Suggestion is to explain why we believe we can get where we want to go. 
      • Ricki: Look hard at scrubbing complexity for Concept 2. 
      • For Concept 2, we are looking and merger between MRSS and MRS, and combining key features. Optical engineers think this may bea mistake. Should see whether the same packaging concern applies to HRS. 
  • Heterodyne Reciever for OST (HERO)
    • Overview of HERO instrument 
      • HIgh spectral resolution of science cases. 
      • 10 to the 7th (Delta lamba over lamba)
      • Cover high bandwidth range (450 gigga herz)
        • 110 microns all the way down to the water line
      • Frequency range divided into six bands to get several positions on the sky.
      • Herschel heritage.
  • Far-IR Imager and polarimeter (FIP)
    • Does not have science driver in terms of prioritization of science. 
    • Polarimetry, magnetiic fields in galaxy, far-IR in background, solar system objects
    • 240 microns, 4 bands 
    • Issues demonstrated with 9 meter cold telescope, will reach confusion limit at 42 miliseconds. 
      • Give this, it is important in terms of surveys, differential polarimerty will allow for high polarimetry. 
      • Would be interesting to see if this can address the mechanical mode concern. 
    • Seeing rays always helps, specifically for mechanical contstraints.
    • Worth noting that background limit detector noise must be at a specific number (Johannes Staguhn). For TRL levels, this is the only instrument that has indicvidual detectors that meet the noise limit. 
    • Super conducting...orders, is this something we have, or is this needed?
      • We have this, but it may not meet the TRL requriements. 
      • We did the IDL run with normal conductors off the shelf, and it does work thermally. 
      • In the report, we would refer to the normal. Later on we can include super conductors. Do not confuse the reader. 
    • Mexiner: Do we need an imager for Conept 2 (MRSS) in constructing images?
      • Jean: if we can include it, do include it. A far-IR imager would be best, if it is scaled down to 5 meters. Polarimetry is important. 
      • Staghun: It has a billion times the mapping speed of PAX, will be a decent imager. 
      • Can descope if we have to. 
      • Detector can work with smooth scanning. For these detectors we can map away. There is fine print, we will have to continually acquire guide stars. 
      • How long can we track, once we have reference frame. Pointing requirements for far-IR are more relaxed. 
        • Dippiro: Do have a scheme to give us this tracking with MISC. There are so many sources per arch field of view that MISC has.
      • Reiki: Will have to think about this, the field here is small, and trade off of depth should be considered.  
      • Team has a lot of tresposcapous on this, the imager may not be a competative instrument. We could get spectral imaging and be fine with this (ALMA does this); however, this is different instrument with OST. 
        • Mounting and placement of the mirrors is the questions. 
        • Reiki: Menitoned Keiperbelt search program. It's not just snap your fingers and swap it out without loosing anything. 
      • If MRSS is the instrument for the pretty pictures, how important is it that other instruments cannot run, is that a problem if we use this as the image source? Full MRSS plus the guider uses full allocation of heat. operating only when other instruments are off? When MRSS is on, the only other thing that will be on is the guider instrument. 
      • Reiki: In picking wavelengths that are not confusion limited, the imager will go deeper. 4080 is unresolved so far. 60-70 microns can detect infrared galaxies. 
      • Can go deep at 70 microns, at red-shift 7 or 8 but there is a discovery space. Local low metalistic galaxies, one can conclude that 8 microns is a good number, for low metalistic galaxies.  
  • High Resolution Spectrometer
    • Overview
      • Push limits for higher spectral resolution using spectrometer. 
      • In MRSS, higher resolution is being provided by fibre peros, which decreases noise bandwidth, depends on how we can push detector performance. 10 he sixth regime, have to detect noise temperature with heterodyne instrument. 
      • Ambitious instrument. 
      • Main science case is protoplanetary disks, dont need to reach confusion limit (10 to the minus 20 is the requirement for MRSS to be background limited). 
      • WIll need photon counter if background limited.
      • COorary: Asked about how much  HERMES measures protoplanetry disks? Scientists want to measure a large number of these, its a low number. Mapping speed is a factor of 1000, its in the single digits. 
      • Mexiner: Include what we are building on for prior missions. 
      • With a transition temperature of 50 mili kelvin (410 to the minus 20). Might have to isolate thermal. 
    • Comments and questions?
      • Phasing of the shell? JWST uses active measurement for alighment of mirror adjustments. Doint this on the ground is feasible. 
        • Reiki: John Lassey (picture from John Lassey would mitigate any concerns).
      • Is HRS considered the most challenging of the instruments? 
        • It is large and requires a lot of space (Cooray added that is 1 ton), but all instruments are challenging.
  • Instrument Suite
    • Susan: From science perspective, are these instruments seen as having their own science to conduct or should they be paired, would each instrument be used for separate observation or would the data be paired?
    • How is the insrtument information presented in report
      • Consistency of pattern of organization in commonality of insrtument (logical flow). Need commonality in how the information is presented and the order of the instrument. This would make it easier to read.
      • Include introduction of spectral resolution, showing interreltation. This would make it more user friendly.
  • General Overview of Suggestions 
    • Reference heritage 
    • Work would be demonstrated with JPL, risk would be minimized with GUSTAL, should explain this. 
    • Show that NASA is investing in demonstrations.
    • Getting power down on local isolator chain to......what number? 
      • Use multiple amplifiers to pump the individual mixers. 
    • Have fewer pixels on the isolator. 
    • Science trade for (concept 2) 4 pixel array, do science and remove technical risk. Have to sell science first. There is a tall technical pull on power isolater trade. Consider descope. 
    • If we dont sell this then we cannot map the ISM. 
    • Micron channel, should we keep this?
      • Specrtral resolution,is 75 thousand, may be sufficient. 
      • 75 thousand is conformtably attainable at 01, 4 kilometers per second. 
      • If we will descope it is reasonable to do away with the 63 micron channel. 
    • This telescope brings angular resolution. Argument would be week to keep the HERO. In descoping, need to consider whether to keep the HERO instrument. 
      • Linear competition is ultra blast. High exotation levels may be a problem. 
      • The protostellar disk case is getting tough,  but doesn't require a large array.
    • Mechanical design section question, Pg. 102,  mentions components being vibration sensitive. Now addressing how vibration sensitivity is corrected can be a problem. 
      • Remove vibration sensitivy, if a clause is not included on mitigation. 

Mission Implementation (Part 1) - 1:30 PM - 2:15 PM

  • Walkthrough each section/open discussion for any topics based on everyones review
    • Interesting and complicated deployment scheme. 
      • Include smaller number of actuators.
    • Is industry involved in deployment of this part? Nothrop Grummana and Harris are helping. 
    • Cryocoolers: Include that we have more than one source and will select the right one later (piece of Northrop Grumman). 
    • Need readers to know that this can be done. 
    • Reiki: FIgure 4.3-4, makes the case of why we are going cold. Natural background limitations. Point of 6 is that the miri coolers already. WHat is the gain in going to 6-7K then going to 4K? Taking on risk withough much sceintifc gain, need to emphasize the gain. The power used in lifting is a concern. For imaging, can you wait for two seconds. We are not designing the system, we are convincing people that this can be done. The requirment should be TRL 9. Its not that we dont need to go colder, its the head lift - need to be able to justify this argument. 
      • Reiki suggested using 6K and explain the science. 
      • Dippirro indicated that we are showing that 4K is achievable. 4K allows for more flexibility in temperature gradience. If 6K works, we can use this. For the purposes of this group, we need to make the case as to why we chose this temperature.
        • Susan: Cooler can be at 4K, other parts of the telescope may be at 6K. By addressing this, this will give us flexibility to support the argument that the cooling may go up to 6K. 
      • 4K has been done, but need justifying. 
      • MIRI experience proved that cooler is a lot more difficult given the current temperature. OST going cooler is bold. 
        • 4K background is supresses, and do not need to worry about gradient. 
      • Bradford responded that there is backround limitation at MRSS of 500. 
    • Concept 1 is described as being questioned (in tone). Need to describe Concept 1 as is. Rather than tearing down Conept 1, include language such as based on analysis to date, we relize this trade, which shows that it can be optimized this way. Describe that here is Concept 1 and in Concept 2, this is what we can do to make it better. 
    • Susan: High data rate downlink (Pg 255), need optical comm to downlink the data. Is optical comm needed? Yes it is need. The requirement is commensurate with what is expected of optical comm by that date. 
      • Reiki: Are there commitments with optical comm will have to be done by a certain date? Getting to 2025, if we dont have optical comm done by 2025, then the question is whether K band can do what opictical comm did? We need to argue what we can do to reduce this data rate. Can simplify what we have on orbit, using K band to simplify data rate.
      • The way certain sentences are written in the interim report shows that optical comm may be needed. If it is true that optical comm will be required (it may be development item for OST), if so, then we need to show are argue how this will be done. 
      • There is a two level strategy included that addresses this, need to modify how it is presented. 
    • Inconsistent formatting and paragraph numbering needs to be fixed. 
    • Phil Stahl's questions/comments:
      • Not using JWST traceable actuator?  We are using the same actuators as JWST but only three as opposed to seve. Perhaps this needs to be clarifed. 
      • Likes use of stray light aperature.
      • Gets into other details.
    • Lee Fineberg:
      • Suggested using 6.5 to 8 meter telescope for Concept 2, 5 meter telescope is not worth it, and 9 would be too much. 
    • Reiki: Low risk point in leveraging JWST investment, why are we going to 5 meters instead of doing jWST clone?
    • Ed Tupper will send in comments.  
      • Constraints were Ttaking miminum size that science cases needed. 
      • Anything to do with confusion limit has very little to do with aperature. As soon as we do imaging surveys this will be different. 
      • Is there an argument in doing 5 meters?
        • John Arenberg is currently looking at this. 
        • In having a 6.5 telescope with an $3M telescope, is there any leveraging that can be done?
        • John Arenberg claimed that this could be done. 
        • Susan: Does this suggest, in tracability of science to instrumentation. Are there key observations that we have to give up in going to five that make this mission less interesting? 
          • We havent looked at a 5 or 6.5 microns, because of sensitivity. 
        • Will a cryogencic 5 meter being sold be a major advance? 
          • Mexiner; Tried to assess whether SPICA would make it through the decadal. 
          • Our diameter is 80% in terms of what JWST is collecting. 
          • In  thining about a 5 meter equivalent aperature. Going to decadal with 5.5 meter aperature given the previous aperature size, how will this 
          • Reiki: There is a lower limit in terms of selling the mission, 5 may be pushing the limit. 
          • Dipirro; We are trying to make everything as small and as cheap as JWST 5. 
          • Mexiner; $3B came about due to a phycological limit (from study manager). 
          • If we dont show a significant gain in telescope size, and cant claim that we have a cold telescope, OST will have a significant problem. 
          • Reiki: Was on panel for coronographic star shades, and the panels response was to do this for some other time. 
          • Reiki: Suggests coming up with mission with 6 meters or more for $3.5B. Push the $3B a little. 
            • Doing the same euiqivalent area as JWST. 
        • In terms of John Arenbergs exercise, can we duplicate JWST? Patrick suggested starting with the actual cost of JWST. 
          • Take JWST and use the berillium. 
          • John Arenberg promised to give OST the JWST chillled cost.
        • Dipirro: Possibly make advanced arrangements, with the review team following us, to present same ideas that arent constrained with HQ constraints. 
        • Run Concept 2 by Mark Devilin (can give us decadal survey outlook). 
        • Include science driver. Such as for H2 lines, arguing that this is the reason we need a 6 meter. Use H2 as scientific justification for a 6 meter. 
        • OST should go back an consider (can invite us to come back for a discussion), and address what is the science arugument for whatever path, what were the trades, so the review team can give us a perspective. Not getting a compelling science case with the 5 meter. Need supportin arguments, 

Mission Implementation (Part 2) - 2:30 PM - 3:15 PM

  • Comments for any of the following:
    • Mission Concept Overview
    • Telescope System
    • Instrument Accommodation Module
    • Spacecraft Bus
      • Asked about the raditator on Pg. 150. This drawing is old but shows the boundary, given the large observatory.
    • Observatory Integration and Test
    • Observatory Thermal Analysis
    • On-orbit Servicing
      • Is this a requirment? Not really. Something that, because of congressional requirements, is needed. Is serviceable, swapping out instruments for on orbit, using IAM to swap out instruments, using robotic method. Will be in sun earth 2. Susan's response, SSPD could resupply fuel, and encouraged OST to touch base with SSPD. OST recieved presentation from Charlie for this. Susan additionally mentioned that we dont need to build alot into the proposal. Replacement of instruments is not the current state, restoralisis can be successful. 
      • Assumptions about servicability are driving the design to be more expensive to build, because we are assuming the older technologies are only available. IAM design made it less structurably stable. May need to further define was servcing means. Should maybe explain further how the robotic arm is useful. This design approach needs to further clarify how it is serviceable. 
      • Reiki: Unqiue problems in servicing cryogenic device. May want to identify this now, but not solve it now. Be careful in terms of the short tearm, and in the long term work on solving. 
    • Enabling Technologies
      • Far-IR detectors 
        • Reiki: Mid-IR detectors paragraph is not adequate. Will not improve stability of mid-IR detectors with a one line statement. Restablishing capability for mirri-detectors. For decadal survey, the current content in the interim report is not suffiecient. Need a detailed discussion regarding detector technology. Suggested assuming demonstrated detector for science, with a goal of improving the science. Assume that we have JWST miri-detector stability. 
        • Roellig: Meeting in Japan. Japanese are interested in working on this at NASA Ames (TRL 2). Technology roadmap includes this need. Lost technical capabilties such as people and their knowledge. . 
        • May be able to improve upon existing scientific performace, by using miri detectors to distribute light
        • Reiiki; Suggested improving pitch with definate development plan where success is likely, and include a goal of improvement of stability.
      • Sub-Kelving Cooling 
      • 4K Cooling 
      • Susan: Technology development does not have a plan going forward. We currently say what we need but there is no mention 
        • Dipirro: We will put this together before this is submitted to HQ.
    • Ground System and Mission Operations
      • Reiki: Section seems short (could be due to data rate). LST will have a huge data center. In doing huge survey, OST will accumulate an eccessive amount of data. This does have to be included at some level. 
      • Reiki: Unqiue aspects: managing cryocoolers, concerned about temerature. Mechanism is constrained across the board. We are saying we are flying TRL 4-5. Temperature brings requirements on shielding. 
        • Dipirro: Starting off with JWST lessons learned. We recognize cryocooling issues.
      • Reiki: Suggested including risk mitigation are for operations. Suggesting a paragraph on mitigation strategies for operations with cryocoolers.
      • Discussion on single point failiure? Flores indicated that there is cross trapping. No single failure analysis has been done but, cryocoolers have full redundancy. TRL design will include a door for local isolator instrument (should include this in the report for top level).

Management and Schedule - 3:15 PM - 3:45 PM

  • General Reccommendations/Comments
    • Proofread report overall for spellinig errors
  • Organization
  • Management Processes and Plans
    • Carter: Not including cost at this level of the interim report. 
    • Susan: This section is underdeveloped. Inlcude lessons learned from JWST in terms of managing mission complexity, mutlipartner, AO's to go out for instruments, Science Team arrangements.
    • Mather: Develop technologies to TRL 6 before completing design (this is a JWST lesson learned). Suggested maintaining backups from critical mission elements, and functional redundancy, consisting of two ways to focus, is very important. If something goes wrong it can't be fixed. Back up way for guide camera, saying the gyros are good enough. Stressed the importance of rehersal. Suggested sending out interface simulators to the team.
    • Better defined  instrument interface. Mass capability was limited for JWST (limited by 5 meter fairing). 
    • Reiki: Capture cryogenic testing from JWST.
  • Top Risks and Risk Mitigation
    • Will identify top risks for Concept 2 and include a risk matrix. 
  • Mission Development Schedule
    • Has potential to be stronger and should include more lessons learned. 
    • Shows a huge amount of paraelle, not much staggering. Schedule was done for US, assumed 10 year development time from beginning to end,  build and instruments would be done in paraell, where if one insrtrment were delayed then 
    • Lessoned learned, both Spitizer and JWST put off space craft development, resulting in launch slips. Should defend not putting off space cradt development. Start on spacecraft early, so that end the end it doesn't result in the long slip. 
    • Consult at the project management level, if they have scheduling suggestions for OST. 
    • Move synopsized version of science requirements further up. 

Appendices - 3:45 PM - 4:00 PM

  • Revisit table in Appendix 2. Shows decoping and required isstruments. Reiki suggested getting rid of the heterogyne with so damage to the instruments. 
  • Mexiner asked Reiki about estimating cost when building something?
    • Reiki's response was garbage in garbage out. 
    • Carter explained OST current approach; proposed 1 kg/1 million. 
      • Reiki mentioned that the problem is coming up with cost where the decadal surveys response is not shocking. The danger of going into the decadal survey is going into the decadal survey with a cost that is too high and then being shocked. Risk is that they are more conservative with the decadal costing. Risk is that they will give us a number/cost now, and then on the record come up with a higher cost. Reccommended getting CATE cost number now from HQ. These four studies should suggest/promote this idea of negotiating CATE cost and forwarding these to the decadal survey. NASA commitment at a HQ level as to the advantages and disadvantaegs. 
        • Carter: OST will have an opportunity to reconcile the cost. Cost estimators read the design and estimate in the dark. If we have an opportunity to reconsile or explain, we can come to closer estimates. 
        • They want a cost that is doubled (60-70% higher).

Summary - 4:00 PM - 4:30 PM

  • Concept 2: cost constraints and telescope size perception issue. Should consider 6.5 meters and not 5 meters for the telescope. Spend less money on instruments 

Action Items

#Action ItemOwner Due Date
1Reviewers take time after the meeting to fill in the charts on any area that needs to be presented to the team.George Reicki 
2Written guidance on what to do to improve the argument for spectral confusion limit. George Ricki
3Share references or articles about red-shifts for galaxies (Bring post doc in who is also first author on key paper)George Ricki
4Schedule offline discussion of HD discussion. Martina Wiedner
5Identify easy comparisons and make sure they are not hanging out (MISC instrument)STDT


Ask optical engineer to run sensitivites for MRSS instrument.

Thomas L. Roellig 

Matt Bradford

7Ask Gary to elaborate on protoplanetar disks for HEREMES (number to get)

8Scheudle off line meeting to discuss detectors. Thomas L. Roellig
9Interested in feedback from George Reicki on detector capabilities (Margaret Mexiner) will send George Reiki/Susan the email list.Margaret Meixner
10Send out interface simulators to STDT management.John Mather
11Susan will collect comments, summarize and send this out to Ruth Carter. Susan  Breon