ACE Weekly 08/07/2013 - 08/13/2013

All ACE spacecraft subsystems are performing as expected.

========================================================================
Orbit/Attitude:

	Type         Attitude
	Date         08/13/2013
	DOY          225 2013
	Thrusters    2R 4R+ 4R-
	Duration     20:17 min
	Start        16:40:16z
	Stop         17:00:33z
	HGAStart     -8.77 deg
	HGAStop      +8.82 deg
	SunStart     10.74 deg
	SunStop      10.89 deg
	SpinStart    4.9476 rpm
	SpinStop     4.9527 rpm
	Nutation      0.21 deg
	Firing       100 pulses
	FuelUsed       0.2994 lbm
	FuelRemain   112.5532 lbm
	FinalSCMass  1346.813 lbm

The next attitude maneuver is scheduled for Tuesday 08/20/2013.

This week's attitude maneuver (0.30 lbm) is larger than usual (0.09-0.18
lbm).  ACE crossed the ecliptic plane on Friday (8/9/2013; DOY 221) and
this maneuver turned the spacecraft from pointing 7 degrees above the
ecliptic plane to 9 degrees below the ecliptic plane.  This is to keep
the spacecraft  at larger sun angles.  These large maneuvers will happen
every 3 months (last occurrence 5/7/2013).

Fuel usage with "weekly attitude maneuvers" has been at the same rate as
fuel usage with "maximum time attitude between maneuvers" (~6.5
lbm/year); even with large maneuvers every 3 months.  There are other
factors: shorter burns are less efficient, longer burns are more
"circular" due to sun-pulse based firing, etc.  But the end result is
that attitude maneuver fuel usage has not changed with the increased
frequency of maneuvers.

========================================================================
OCRs:

None

========================================================================
Activities:

Data Capture:  100%  DOY 216-223 2013

A fourth Santiago range test is scheduled for Wednesday 7/14/2013.  Over
the course of these tests, several issues have been resolved and
Santiago may be close to the point where FDF can use their
range/tracking data.  The buffer overflow problem has not been resolved
(a 10,000,000,000 nanosecond round-trip-light-time cannot be stored by a
4 byte integer 4,294,967,296), but FDF seems to be able to account for
this by adding 8,589,934,592 to the range data (2 "overflows").  If DSN
antenna time becomes problematic with the reduction from 13 to 12
antennas (12/23/2013), it may be worthwhile to investigate using
Santiago to supplement ACE's southern-hemisphere ranging needs.  (These
tests were originally planned so that DSCOVR could use Santiago.)


========================================================================
Anomalies:

None