XTENEWS#5: XTE telemetry, and other frequently-asked questions

[Alan Smale <alan@osiris.gsfc.nasa.gov>]

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       XTE telemetry, and other frequently-asked questions
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XTENEWS#5                                          21st April 1995


In this message we attempt to clarify the telemetry issue, and provide
answers to some other questions that we get asked rather frequently,
namely signatures, electronic proposal submission, and using ASM
hardness to trigger TOOs.


0. Breaking News
----------------

Q. How do I find out the very latest information about XTE; the
availability of matrices, status of corrections to the Technical
Appendix, etc?

A. See the "What's New" link on the XTE GOF homepage, and get a copy
(if you haven't already) of the PostScript file NRA_errata.ps in
anonFTP legacy.gsfc.nasa.gov:/xte/nra/appendix_f/addenda.  Also be
aware that this directory contains further examples of spectral
simulations that you might find useful.  
(GOF homepage: http://heasarc.gsfc.nasa.gov/docs/xte/xte_1st.html)


1. Telemetry rates
------------------

Q. Could you clarify the use of XTE telemetry and the amount that
can be reasonably proposed for?

A. This is discussed in section C.2.2 (4) on page C-6 of the NRA in
which justification of requested telemetry is discussed. To emphasize
the points of this paragraph:

   * The nominal effective telemetry rates for the PCA and HEXTE
instruments are ~22 kbits/sec and ~8 kbits/sec respectively.

   * Users can (and should) propose higher telemetry rates if
justified by the proposed science.

   * Since it is not possible before launch to estimate what average
telemetry rates can be sustained for many orbits, proposers are
encouraged to describe how the proposed science could be enhanced if
additional telemetry capacity were to become available.

   * Proposers should recognize that for sustained average telemetry
rates _much_ larger than the nominal rates, some of the recorded
science data will not be telemetered to the ground; this depends on
the duration of the observation and the onboard recorder management.


2. Signatures
-------------

Q. Do I need an institutional signature?

A. Neither NASA Headquarters nor the XTE GOF require an institutional
signature for the science (Phase I) proposals, due April 27.  This
information was unfortunately not available when the NRA went to
press, although it was included in XTENEWS#2. The signature box is
there for those institutions which require internal approval of all
proposals regardless of whether they contain a budget.  Signatures
will only be required for Phase 2, in which successful proposers will
be asked to submit a budget.


3. Electronic submission.
-------------------------

Q. Do I really have to do this? Why do I have to submit electronically
AND with 20 hardcopies? As long as I submit electronically by the
deadline, does it matter if my hardcopies arrive late?

A. Yes. Electronic submission ensures that all the necessary
information flows accurately into the proposal database, and from
there into the command generation software. A long time ago, we used
to type all this information in by hand from the proposal hardcopies;
it's not difficult to see (a) how mistakes could easily creep in, and
(b) how much personpower such an approach took. Electronic submission
also enables us to perform automatic proposal verification, which most
people are very enthusiastic about.  Likewise, we don't have the
personpower to generate the necessary hardcopies ourselves. Both the
electronic submission and the hardcopies MUST arrive at the address in
the Announcement by (or on) Thursday, April 27th - any delay in
receiving either would jeopardize the schedule for the proposal review
process, and this must therefore be considered a hard deadline.


4. TOOs
-------

Q. Can ASM hardness be used as a trigger for TOOs?

A. On p. 83 of Appendix F, it says that the ASM can be used in this
way. However, the capability of doing this is not yet implemented, and
thus the Constraints form does not have a section for specifying ASM
hardness. We believe that we will be able to implement this
possibility in the future, for those observers who will be willing to
take responsibility for later working out this determination. If you
want to trigger on a hardness state, explain what you want to
distinguish in the way of source behavior on the remarks section of
the Target form. (If possible, of course, put an ASM rate as trigger
on the Constraints page.)


5. GOF Service
--------------

Q. How do I get the best service from the XTE GOF?

A. OK, nobody actually asked this question, but we'd like to answer it
anyway. We're getting a lot of community questions, ramping up sharply
as the deadline approaches. We're still managing to answer all Emailed
questions within 24 hours (and the vast majority within 2 hours), and
hope to keep this up till the last, if the coffee doesn't run out.

Quickest response will come from using the xtenra@athena.gsfc.nasa.gov
Email exploder for XTE and NRA questions, and the rpshelp@athena...
address for RPS questions. If you send Email to individual members
there may be a delay while the mail is rerouted to the right
individual. For the next week or so, phoning is not recommended. We
will generally answer phonemail queries by Email to preserve a record
of our answers. 

Finally, if you've read this far, thank you. We like people who read
the documentation!

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