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Preview of a Web-based GUI

Interface to SPICE

“WebGeocalc”

The NAIF and UCD TeamsAugust 22, 2011

SPICE components are not restricted under ITAR

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Current Access to SPICE

• To use SPICE today, one needs to:– write a program* that calls SPICE modules, or– use a SPICE-based program someone else has written

*Languages available: Fortran 77, ANSI C, IDL, MATLAB, Java Native Interface

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Making it Easier

• NAIF and UCD believe there is a “market” for a GUI interface to SPICE

– Especially if implemented in a client-server architecture where...» “Client” is the user’s web browser» “Server” is usually the NAIF server

• Supplied with data (kernels) from lots of missions, all managed by NAIF• But such a server could be installed and operated from anywhere

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Why Build This Tool?

• Provides much SPICE capability to people who can’t or won’t do programing

• Can be used as a “gold bar” validation for SPICE-based pipeline code being written by a customer

• Customers can obtain “one-off” answers to many kinds of geometry questions very quickly

– E.g. in a meeting– E.g. back of the envelope analysis

• Provides outputs in several forms:– Screen displays, saved to a log file for subsequent use– Tabular, exported into Excel– Plots, pasted into other documents

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“Both Kinds” of SPICE Calcs.

• You’ll see that the tool does “both kinds” of SPICE computations

– Compute parameter “blah” at time T– Find the times, or time intervals, when:

» parameter “blah” has some value or is in some range» when condition “blurp” is true (or is not true)» (NAIF calls this “geometry finder”)

• The user may chain together multiple computations.

– Rather like an interpreted language

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Browser Appearance to the User

Inputs

Outputs KernelsUsed

Saved Outputs

for Reuse

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Sample Screenshot - 1

Inputsarea

Outputsarea

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Sample Screenshot - 2

Outputsarea(more area shown)

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Why Show This Tool to the PDSMC?

• Do you think WebGeocalc would be useful to the space science community?

• Have you any recommendations about from whom to get some functionality and usability feedback?

Also…• We believe this tool would not serve any function

within the core of the PDS4 system, but thought the MC should have a chance to weigh in on this.

– Comments?

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WebGeocalc Demo Overview

• Mark Rose will run a few examples using the current, very early version of WebGeocalc.

– It’s not yet ready for testing by the MC or others.

• Much planned functionality is not yet available, so the examples shown are not very complex and don’t have as much “science flavor” as one might like.

• Some changes to what you’ll see are already planned.

– Don’t get hung up on the details.

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Four User Scenarios

1. Compute and plot the range from Odyssey to Phobos, regardless of whether or not Mars is occulting Phobos.

2. Within a user supplied bounding window, find all of the Odyssey equator crossing times.

3. Within a user supplied bounding window, find the time intervals

when Mars Odyssey is in view of the MER Opportunity rover.

4. a) Within a given bounding window, find the times when Cassini is within X km of Titan.

b) Using any one interval from the previous result, compute distance and sub-spacecraft location in the Titan-fixed reference frame.

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Mark Do the Demo Now

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Challenges

• Making it “easy” for users to load the right and necessary kernels is the largest challenge.

– So far we have largely put off this part of the work

• Will the GUI interface, including its Help and SPICE Error Message displays, be sufficient to get users confidently achieving what they want?

“Kernel management is the Achilles heel of SPICE” --B.C.

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Next steps

• Who might we talk to to get feedback on the concept and planned functionality?

• Who might we sign up to do some alpha-testing in a few months?

Please contact Chuck with your suggestions. Thanks in advance!

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Backup

• Some ideas of additional planned capabilities– Provide “easy, informed” loading of kernels, including from PDS

archives, from flight operations collections, and generic kernels– Allow users to save, then later recall, a set of config parameters– Support use of a command language– Provide kernel summary/characterization capability– Draw a visualization representing observing geometry– Draw instrument field-of-view footprint– Compute/display certain geometry items at cursor location in

graphic– Allow appropriate computed results to be displayed as a movie– Interface with a glossary of terms– Interface with star catalog– Interface with useful kernel utility programs (brief, ckbrief, etc.)