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RXTE Cycle 11

Information for Proposers Regarding Proposal Submission,

Evaluation, Selection, and Implementation

C.1 Proposal Preparation and Submission

C.1.1 General Observing Parameters

The current Announcement covers the 12 months of observations to be carried out with RXTE beginning on or around March 1, 2006. These observations will be selected from proposals submitted to NASA in response to this Announcement.

Once the targets to be observed are identified, the Science Operations Center (SOC) is responsible for generating the science time-line under the specified constraints. Under normal operating conditions, the only constraint is the angle between the target and the Sun, which must be larger than 30 degrees. Proposers may specify additional constraints on their observation. Maneuvers are scheduled to occur during passage of the spacecraft through the South Atlantic Anomaly (SAA) or, where possible, when the target is occulted by the Earth. Large maneuvers occur at ~6 degrees per minute, and a typical maneuver between unrelated targets incurs approximately 500 seconds of overhead. Approximately 20 maneuvers per day can be performed. These values may change as a result of further in-orbit experience. Scans of extended targets can be made at lower slew rates. There are no restrictions regarding the maximum amount of observing time or the maximum number of targets that may be requested. Proposals must have at least one target, and every observation must be a minimum of 1000 seconds in duration.

Proposals may be submitted for single targets with short or long observation times, or for larger programs involving multiple targets or significant amounts of observing time. All proposals will be reviewed in the same peer review, which should result in the selection of a mix of large, medium, and small programs. However, Cycle 11 proposers are specifically encouraged to consider projects that would profit uniquely from large amounts of observing time, to enable investigations of significantly greater scope than those possible in earlier RXTE observing cycles. Accordingly, large proposals, defined as those that request observing times of 500 ksec or more, will be given special consideration and are allowed 6 pages for the Scientific Problem and Technical Feasibility section of the proposal (see section C.2.2.2).

There are no specified key projects for RXTE. Proposers may request observations extending beyond the end of the formal 12-month period covered by this Announcement, but must present compelling scientific justification for such observations. For the current observing cycle, it is anticipated that observing time will be awarded to about 100 proposals.

RXTE can respond quickly to the transient behavior of astronomical sources, so the exact scheduling of time-critical observations may be done only a few days or weeks prior to the observation. One of the primary design criteria for RXTE was the rapid response to Targets of Opportunity (TOO's). Proposals to observe TOO's are allowed under this Announcement. Such observations can be triggered either by a change in flux as measured by the ASM, or by optical, radio, or other external triggers. The automatic SOC software may detect some critical changes of ASM flux, however, it is the responsibility of the PI to monitor the behavior of the source of interest using the online ASM light curves. For external triggers, it is the responsibility of the Principal Investigator to notify the SOC that the triggering event has occurred. When a TOO is triggered and approved by the RXTE Project Scientist, a repointing of the satellite can be effected in as short a time as seven hours from the time of notification. Data rights from a TOO proposal that has been peer reviewed and approved in response to this Announcement are identical to those of a non-TOO proposal that has been peer reviewed and approved in response to this Announcement. Further details on proposing for observations of Targets of Opportunity can be found in the RXTE Technical Description. Prospective proposers should note that reductions in staffing resources may affect the capability of the SOF to respond to TOO's under some circumstances. Accepted TOO proposals will be carried out as proposed on a best efforts basis.

One advantage of this mission in comparison to previous missions is the relatively unconstrained solar angle constraint that makes available approximately 93% of the sky at any given time. The large sky accessibility affords an opportunity for coordinated ground-based and RXTE observing, as a given target can be scheduled for observations during night-time hours at ground-based telescopes. Up to 4 coordinated observations per month will be designated for "special handling" by the peer review panel. Observations with this designation will be assigned a high priority for matching the requested coordinated observing times. There is no limit on the proportion of observations that can be accepted that include time, phase, or other observing constraints.

C.1.2 Who May Propose

Proposals may be accepted from any institution within or outside the United States. RXTE proposals must identify a Principal Investigator (PI), who assumes full responsibility for the conduct of the scientific investigation.

Following selection, the SOC will communicate only with the person identified as PI or lead Co-Investigator (Co-I), who can also serve in this role in the event that the PI is unavailable. It will be the PI's responsibility to respond to any questions concerning observational constraints or configurations.

C.1.3 Who May Propose -- Foreign Participation

NASA welcomes proposals from outside the U.S.. Proposals from outside the U.S. and U.S. proposals that include non-U.S. participation must be endorsed by the respective government agency or funding/sponsoring institution in the country from which the non-U.S. participant is proposing. Such endorsement should indicate that the proposal merits careful consideration by NASA and that, if the proposal is selected, sufficient funds will be made available to undertake the activity as proposed.

All proposals must be typewritten in English and comply with all other submission requirements stated in the Solicitation Announcement. All non-U.S. proposals will undergo the same evaluation and selection process as those originating in the U.S. All proposals must be received before the established closing date; those received after the closing date will be held for the next proposal cycle. Sponsoring non-U.S. agencies may, in exceptional situations, forward a proposal without endorsement to the submission address if endorsement is not possible before the announced closing date. In such cases, however, NASA's Office of Space Science should be advised when a decision on endorsement can be expected.

Successful and unsuccessful proposers will be contacted directly by the NASA Office of Space Science. Copies of the letters of notification will be sent to the sponsoring government agency. Should a foreign proposal or a U.S. proposal with non-U.S. participation be selected, NASA's Space Science and Aeronautics Division will arrange with the foreign sponsor for the proposed participation on a no-exchange-of-funds basis, in which NASA and the non-U.S. sponsoring agency will each bear the cost of discharging their respective responsibilities.

Depending on the nature and extent of the proposed cooperation, these arrangements may entail:

  • an exchange of letters between NASA and the foreign sponsor; or

  • a formal Agency-to-Agency Memorandum of Understanding (MOU).

    C.1.4 Export Control Guidelines Applicable to Foreign Proposals and Proposals Including Foreign Participation

    Foreign proposals and proposals including foreign participation must include a section discussing compliance with U.S. export laws and regulations, e.g. 22 CFR Parts 120-130 and 15 CFR Parts 730-774, as applicable to the circumstances surrounding the particular foreign participation. The discussion must describe in detail the proposed foreign participation and is to include, but not be limited to, whether or not the foreign participation may require the prospective proposer to obtain the prior approval of the Department of State or the Department of Commerce via a technical assistance agreement or an export license, or whether a license exemption/exception may apply. If prior approvals via licenses are necessary, discuss whether the license has been applied for or if not, the projected timing of the application and any implications for the schedule. Information regarding U.S. export regulations is available at http://www.pmdtc.org/ and http://www.bxa.doc.gov/. Proposers are advised that under U.S. law and regulations, spacecraft and their specifically designed, modified, or configured systems, components and parts are generally considered "Defense Articles" on the United States Munitions List and subject to the provisions of the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120-130.

    C.2 Proposal Format and Content

    C.2.1 Overview

    In the proposal review, the scientific and technical merits of the proposed investigation will be reviewed, including the appropriateness of using RXTE to address the scientific objectives and its relevance to furthering our understanding of high energy astrophysical processes. Based upon the criteria listed in Section C.3, a panel of scientific peers will evaluate the scientific and technical merits of proposals received in response to this Announcement.

    C.2.2 Proposal Details

    C.2.2.1 Proposal Content

    The proposal must include a standard Cover Page form, a General Form, the scientific and technical justification (as described below), a status page describing previously-awarded RXTE observations (see below), a Target Summary form, Target Forms as needed, and, optionally, Constraints Forms as needed (see Appendix D). The information in the forms will be entered into a data base that will be used in cataloguing and evaluating proposals. The forms must be completed in the prescribed format. Cost sections should not be submitted and will not be considered under this Announcement.

    The abstract should be limited to 800 characters, including spaces between words, with no embedded commands, i.e., flat ASCII only. Abstracts that exceed this length will be truncated automatically at 800 characters when entered into the data base. Abstracts and target lists for selected proposals will be made available on publicly accessible data bases.

    Proposers should also note that the pointing positions given in the Target Form will be used to point the spacecraft and therefore should exercise considerable care in specifying these positions. Pointing errors can seriously degrade the data from an observation. Positions must be stated in J2000 coordinates.

    A target number should be assigned to each proposed pointing to designate the priority of that particular pointing within an investigation requiring multiple pointings. If it is necessary for the peer-review committee to reduce observing times, an attempt will be made to preserve the highest priority observations.

    Proposers who have been awarded RXTE observing time in prior Cycles should indicate the status of these programs. Proposers with RXTE programs approved in Cycles 1 through 10 are required to append a page to their proposal listing, by Cycle, proposal number and title, their previously-accepted RXTE proposals and the status of the data analysis or publications that have followed from them. Programs awarded to the Principal Investigator and any major Co-Investigators should be included.

    The discussion of the scientific investigation is limited to 4 (6) pages including references, figures, and tables. It should provide the following information, and be structured as follows:

    (1) Scientific Problem. (Suggested text length: 2-3 pages.) Clearly state the scientific problem to be addressed, with relevant scientific background and references to previous work. Show how the proposed RXTE observations and subsequent data analyses are expected to address the problem and advance prior knowledge in the context of past work in this research area. Justify the use of RXTE for the proposed investigation by showing how the observations use the unique strengths and capabilities of RXTE.

    (2) Technical Feasibility. (Suggested text length: 1 page.) Show how the requested observations (exposure time, telemetry requirements, etc.) make possible the achievement of the scientific objectives. State how targets or pointing locations were selected. List assumptions about source intensity, surface brightness, and spectrum. Estimates of both count rates and total counts needed to successfully accomplish the investigation must be provided. At a minimum, the Portable Interactive Multi-Mission Simulator (PIMMS - see the RXTE Technical Description) should be used to estimate count rates. The spectral fitting software XSPEC, or the online simulator WebSpec, may also be used to estimate count rates or demonstrate how the spectral data will be analyzed. Timing simulations are strongly encouraged. Note that it is in the proposer's best interest to provide enough detail to allow a reviewer to understand the proposer's target brightness assumptions and to reproduce the count estimates. The proposer should demonstrate that those estimated counts are sufficient to extract the desired astrophysics from the observation. RXTE has numerous data processing configurations and the user must select the configurations for the on-board processing of the data stream for his or her proposed observations. It is the proposer's responsibility to be knowledgeable of the configurations and their limitations.

    (3) Targets of Opportunity. Targets of Opportunity (TOO) may be proposed. Proposers should state in their justification the estimated probability that the TOO trigger will occur during the observing period covered by this Announcement, and how they arrived at this estimate. To simplify the proposal evaluation process, proposals must not contain a mix of TOO and non-TOO targets.

    (4) Constrained Observations. The proposer may desire to place constraints (monitoring, coordination with observations at other wavelengths, uninterrupted, etc.) on the proposed observations. A coordinated observation can be designated for "special handling." However, this designation places increased emphasis on matching the absolute coordinated schedule; a change in the coordinated schedule can be accommodated up to 60 days in advance of the observation. Up to 4 "special handling" requests per month will be considered, so such constraints must be demonstrated as feasible and scientifically justified. The previously-available capability of performing alternate targets, defined as a substitute for the primary target if the primary target becomes scientifically uninteresting (e.g., becomes too faint), has been discontinued due to the operational burden. Proposers should also note the potential impact on time-constrained observations of an interruption by a TOO.

    (5) Justification of Telemetry Use. Requests for telemetry beyond the nominal rates for each instrument must be justified due to the constrained nature of this resource. Similarly, rates significantly below these allocations may be viewed as an under-utilization of RXTE and should likewise be justified. The allocated, nominal rates are, assuming an observing efficiency of ~60%, ~40 kbits/s for the PCA, and ~8 kbits/s for the HEXTE. The proposer is also invited to discuss, within the page limit, possible uses of increased telemetry if additional telemetry were to become available. In particular, the proposer may specify the key parameter (temporal resolution, spectral resolution, layer ID, etc.) to alter in the instrument configurations if such an increase in telemetry were found to be feasible during his/her observation.

    (6) PCA Constraints. The PCA is currently being operated with reduced duty cycles for three out of the five PCU detectors. Proposers should calculate exposure times and discuss technical feasibility with an expectation of using an average of three PCUs. If special circumstances warrant or require the use of four or five PCUs for an observation (e.g., faint source spectroscopy or investigations of weak QPO signals), then a quantative justification must be clearly stated in the Technical Feasibility section. (Although every effort will be made to fulfill requests for more than three PCUs, operational limitations make it impossible to guarantee that the requested number of PCUs will be available.) In addition, it should be noted that some observations, especially those for source monitoring, may be conducted with two PCUs, and proposers should discuss the expected impact of this limitation on their observing program.

    C.2.2.2 Page Restrictions, Certifications, and Quantity

    As a result of the large number of proposals anticipated in response to this Announcement, strict page limits will be enforced. The scientific justification should consist of not more than four pages (six for large programs; see C.1.1) where each side of a sheet of paper with text or figures is considered a page. When printed out, type should not be smaller than 10 point (standard typewriter size print), and is limited to not more than 55 lines per page. Margins should be a minimum of 1 inch on all sides. These pages and the associated forms comprise the scientific proposal and should provide the peer panel members with the essence of the proposed scientific investigation.

    Proposals should be submitted electronically. RPS submission of the cover forms is still required. In addition, the cover forms and scientific justifications should be submitted electronically as two PostScript files. No hardcopies need be sent by postal mail. A full step-by-step description of the electronic submission process can be obtained from the relevant RXTE Web pages on Cycle 11 proposal submission.

    Reviewers will consider only those pages in each proposal section that do not exceed the page limits specified below.

      Section                  Page Limit     Comments 
      Cover Page               1              no other cover necessary
      General Form             1               
      Target Summary           1                                
      Target Forms             1 or more      as needed   
      Constraints Forms        1 or more      optional, as needed  
      Scientific Problem and   4/6            includes text, figures, charts, 
      Technical Feasibility                   tables, references      
      Status of RXTE Programs  1              new requirement - see C.2.2.1.
      Vita of PI               1              optional 

    C.2.2.3 Technical Information Resource

    Technical questions concerning the RXTE mission and requests for assistance in proposal submission may be addressed to Dr. Padi Boyd, RXTE GOF Manager, at:

    Dr. Padi Boyd
    RXTE Guest Observer Facility
    Code 662
    Goddard Space Flight Center
    National Aeronautics and Space Administration
    Greenbelt, MD 20771-0001
    TEL: 301-286-2550, FAX: 301-286-0708
    E-mail: xtehelp@athena.gsfc.nasa.gov

    C.2.2.4 Electronic Forms Submission

    All proposers must electronically submit their Cover Page, General Form, Target Summary, Target Forms, and Constraints Forms. Proposers who do not have access to electronic communications must contact Dr. Boyd at the above address no later than two weeks before the submission deadline. Electronic submission facilitates efficient proposal processing and reduces the likelihood of the introduction of transcription errors into the proposal and observation databases. For electronic forms submission, the RXTE Guest Observer Facility has made available Remote Proposal Software (RPS) (see Appendix D). Additional information on RPS is available from the RXTE GOF web site at http://rxte.gsfc.nasa.gov/,

    In addition, proposers must also electronically submit their Forms as PostScript files, and their scientific justification and associated materials as PostScript files, as described in C.2.2.2 above.

    C.3 Proposal Selection, Evaluation, and Implementation

    C.3.1 Evaluation Criteria

    Stage 1 proposals will be evaluated with respect to the criteria specified in Section C.3 of the NASA Guidebook for Proposers Responding to a NASA Research Announcement - 2004 (excluding cost), where it is understood that the intrinsic merit of a proposal shall include the following factors:

    • The suitability of using the RXTE observatory and data products for the proposed investigation;
    • The degree to which the investigation uses RXTE's unique capabilities;
    • The feasibility of accomplishing the objectives of the investigation within the time, telemetry, and scheduling constraints; and
    • The feasibility of the proposed analysis techniques.

      Evaluation of a proposal's relevance to NASA's objectives includes the consideration of the potential contribution of the effort to NASA's mission as expressed in its most recent NASA strategy documents and to the objectives and goals of the RXTE mission.

      C.3.2 Proposal Selection

      RXTE proposals will be evaluated by a scientific and technical review panel convened by NASA. All proposals submitted in response to this Announcement and received by the proposal deadline will be evaluated for scientific merit and for technical feasibility with respect to spacecraft and observational constraints. From experience with previous solicitations, a substantial oversubscription of RXTE observing time and available telemetry is expected.

      To aid in prioritizing investigations, proposals will be assigned a numerical grade by the peer evaluation panel. Proposed observing programs must receive a high ranking to be considered for selection. The detailed observing plan (timeline) will be formulated and implemented by the SOC. It is the intent of NASA that all selected observing programs be carried out, although scheduling constraints and TOO observations may require rescheduling some observations.

      Proposers need not repropose if a selected observing program is not carried out during the current observing period. Note that in accordance with established RXTE policy, proposers of Cycle 10 TOO observations will be required to repropose their observing programs if the TOO has not been carried out during the Cycle 10 period. Similarly, successful proposers of Cycle 11 TOO observations will be required to repropose their observing programs if the TOO is not carried out during Cycle 11.

      Since RXTE has so many possible instrument configurations, and many of the targets that RXTE will observe are expected to vary with time, it is expected that individual targets may be observed many times without exhausting the science that can be obtained. The peer evaluation panel will judge whether a proposed observational program essentially duplicates one or more observations made earlier, including those performed during the IOC period. The peer evaluation panel may recommend that two or more proposals from different investigators to observe the same source be scheduled, if the proposals have sufficiently high scientific merit. Requests from an investigator to observe a particular source more than once or to observe multiple sources with the same scientific goal should generally be made in a single proposal. Separate proposals to observe the same source more than once, each time with different scientific goals, are acceptable if the goals could not be attained simultaneously in a single observation. The acceptance of a scientific target in previous cycles does not preclude it from being proposed (or reproposed) in this cycle if the goals could not be attained with data currently in, or anticipated to be in, the RXTE public data archive. Scientific justification must be provided in each of the situations described above.

      While a balance between large, medium, and small observing programs is still sought, the trend towards larger observing programs is encouraged.

      C.3.3 Implementation of Approved Observing Programs

      All approved targets will be placed into an observation database. Each observation will be assigned a unique identifying number. It is the responsibility of the RXTE mission planning and operations team at the RXTE Science Operations Facility (SOF) to produce a mission timeline out of all approved observation requests. The process of mission timeline generation is split into two parts: first, for the entire period covered by this Announcement, a long-term mission timeline (LMTL) will be generated with a precision of about a week. Additional LMTL's will be generated in response to TOO's and other timeline changes as necessary. Second, about three weeks prior to the execution of the observations, a short-term mission timeline (SMTL) will be produced on the basis of the LMTL. The SMTL is used for the automatic generation of the required spacecraft commands. It will be optimized a final time approximately one week prior to the start of a particular observation.

      Targets are scheduled in the LMTL to achieve maximum efficiency in the observing program within the operational constraints of RXTE. Unconstrained observations are thus scheduled to produce the highest observing efficiency. Any observation requiring time constraints will be designated as "time critical" and its priority in scheduling will be related to its peer review grade.

      The SOF will make its best effort to schedule all approved observations. All observations that are not scheduled or that were scheduled but not successfully executed for whatever reason will automatically be rescheduled within the current observing cycle. Approved non-TOO observations will be carried over into the observing program of the next observing cycle. Approved TOO observations will not be carried into the next observing cycle.

      If observations are cut short by mission timeline optimization or other constraints, a completion criterion will determine whether a given target is scheduled for additional observing time. The completion criterion for each requested pointing with RXTE is 80% of the recommended exposure time, regardless of the grade assigned to the corresponding proposal by the peer evaluation panel.

      Any constraint on the scheduling of observations must be stated and justified. SAA passage and Earth occultation will, of course, interrupt the average observation. Long observations of low telemetry usage will likely be interspersed with high telemetry rate, short observations. Observers who desire uninterrupted observations may set the "uninterrupted" constraint flag, but must justify the scientific necessity and must show that the observation is feasible.

      Users should also note that a prime purpose of RXTE is the capability to respond to Targets of Opportunity (TOO's). Any observation may be interrupted by a TOO. The priority grade assigned to a target will indicate the susceptibility to interruption likely for that target. High-priority, time-critical targets will have the least chance of interruption by a TOO (but still not zero). Interrupted observations will be completed at a later time. Note that proposers are not permitted to propose a TOO that would be triggered by PCA or HEXTE data that is proprietary to another observer. They may, however, propose a TOO that may be triggered by PCA or HEXTE slew data, by RXTE ASM data, or other means.

      Investigators whose proposals are selected will receive the resulting data in a form suitable for analysis. Twelve months after this receipt, the data will be placed in the public domain via the RXTE data archive.

      C.4 Schedule

      The current schedule for the review and selection of proposals for the tenth observing cycle on RXTE is listed below. Note that the dates of events planned beyond the Proposal Due Date are estimates and subject to change.

             Date		   Action

      January 2005 Release of NASA HQ's ROSES-05 Announcement July 12, 2005 Release of this Web Announcement Sept 19, 2005 Notices of Intent Due Sept 19, 2005 Proposals Due November 2005 Review; scheduling commences March 1, 2006 Begin Cycle 11 Observations

      Proposals may be submitted at any time during the period prior to the Proposal Due Date. Proposals received after the due date will not be reviewed during the current opportunity, but will be held for the next review cycle at the request of the proposer.


      The ROSES-05 Announcement "Research Opportunities in Space and Earth Sciences - 2005", describing the "Rossi X-ray Timing Explorer Guest Observer Program - Cycle 11

      Description of the RXTE Guest Observer Program

      Information for Proposers Regarding Proposal Submission, Evaluation, Selection, and Implementation

      Filling out RXTE Proposal Forms