" F R I N G E S "

S P A C E   I N T E R F E R O M E T R Y   M I S S I O N   N E W S L E T T E R

                               Number 28, June 20, 2003


SIM ENTERS PHASE B !

The SIM Project has just successfully passed its most important milestone to
date, on its path to launch in 2009.  By authorizing SIM to enter Phase B, NASA
reaffirms its commitment to to this mission, and the revolutionary science
results that it expects to provide to us.

    Here is what has happened during the last few months to reach this milestone

For the last several months, Project staff have prepared for the reviews which
had to be successfully passed in order to enter Phase B.  The first, and
largest, of these reviews was the Preliminary Mission and Systems Review (PMSR),
which was held April 29-30.  Three review teams listened to presentations by
Project staff on every aspect of the mission: science objectives, cost,
schedule, technology maturity, instrument and mission design, and margins,
reserve, and risk items.  There was also a shelf-full of documentation for
inspection.  The teams were:

JPL SIM Standing Review Board (SRB), chaired by Tom Fraschetti
JPL Systems Management Office 'Red Team', chaired by Glen Cunningham
NASA Navigator Program Independent Review Team (IRT), chaired by Vernon Weyers

The review boards were (mostly) very impressed with the maturity of SIM in each
of the major areas covered by the charters.  The only significant exception was
the apparent lack of a detailed plan for Phase B.  (Phase B runs from August
2003 - October 2005).  On June 6, the Project briefed members of the review
teams with a clearer presentation of the Phase B plan, satisfying their concern
and resulting in their unanimous recommendation for Phase B entry.

With the approval of the three review boards, the Project and review board
chairs briefed JPL's Program Management Council (PMC) at the Initial
Confirmation Readiness Review (ICRR) held at JPL on June 10th.

The final step came this week with the Project and review board chairs briefing
the Space Science Enterprise Program Management Council (EPMC) at NASA
Headquarters on June 18.  With the EPMC's approval, we expect the formal
authorization for Phase B entry to arrive shortly.

    What is the significance of this milestone?

Phase B is the 'Preliminary Design Phase' of a NASA Project.  Construction of
flight hardware begins with Phase C/D (October 2005 for SIM).  'Preliminary' is
a bit misleading, as many aspects of the SIM design are in fact very mature.  In
previous Newsletters, we have reported on the technology milestones which
NASA Headquarters has been tracking.  Completing the first 4 (of 8) was one of
the requirements for Phase B entry.  Milestone #5 was completed in March 2003, a
month ahead of schedule (see Newsletter #27).

After a well-earned celebration, Project staff are now hard at work filling out
many details of the instrument and mission design, as well as continuing with
testbeds designed to verify the remaining 3 technology milestones.

The next review is the System Requirements Review (SRR) scheduled for 3 days in
November 2003.  At this review, the Project's requirements - on science,
instrument and mission - will be examined for sufficient maturity, and for
consistency across the different subsystems.

    A step closer to microarcsecond astrometry

The SIM teams can be justifiably proud of what they have achieved to date.  The
promise of microarcsecond astrometry - for detecting terrestrial planets, and
for fundamental stellar, Galactic, and extra-galactic astrophysics - remains as
exciting as ever.  SIM is perceptibly closer to reality - only 6 more years to go!

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Steve Unwin, Editor                              stephen.unwin@jpl.nasa.gov

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