NASA Hubble Space Telescope Daily Report #4707

HUBBLE SPACE TELESCOPE DAILY REPORT #4707

PERIOD COVERED: 5am September 30 – 5am October 1, 2008 (DOY 274/0900z-275/0900z)

OBSERVATIONS SCHEDULED

FGS 11299

Calibrating the Mass-Luminosity Relation at the End of the Main Sequence

We propose to use HST-FGS1R to finish calibrating the mass-luminosity relation for stars less massive than 0.5 Msun, with special emphasis on objects near the stellar/substellar border. Our goals are to determine Mv values to 0.05 magnitude and masses to 5%, and thereby build the fundamental database of stellar masses that we will use to test theoretical models as never before. This program uses the combination of HST-FGS3/FGS1R at optical wavelengths, historical infrared speckle data, ground-based parallax work, metallicity studies, and radial velocity monitoring to examine nearby, subarcsecond binary systems. The high precision separation and position angle measurements with HST-FGS3/FGS1R {to 1 mas in the separations} for these faint {V = 10-15} targets simply cannot be equaled by any ground-based technique. As a result of these measurements, we are deriving high quality luminosities and masses for the components in the systems, and characterizing their spectral energy distributions from 0.5 to 2.2 microns. One of the objects, GJ 1245 C with mass 0.074 +/- 0.002 Msun, is the only object known with an accurate dynamical mass less than 0.10 Msun. The payoff of this proposal is high because the six systems selected for final observations in Cycles 15 and 16 have already been resolved during Cycles 5-13 with HST FGS3/FGS1R and contain most of the reddest objects for which accurate dynamical masses can be determined.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS:

11518 – GSAcq 2,3,2 Failed to RGA Hold

GSAcq 2,3,2 scheduled from Day 275/02:34:31 to 02:41:59, failed to RGA Hold. Mnemonics F2STOPF, QF2STOPF flagged, and upon entry to FN FMT at 02:36:22, FSTOP, GSTOP and QSTOP also flagged.

Astrometry Observation FGS1 #11299 affected.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                        SCHEDULED      SUCCESSFUL
FGS GSacq                12                   10
FGS REacq                01                   01
OBAD with Maneuver       26                   26

SIGNIFICANT EVENTS:

Flash Report:

As a result of NCS cooler and the Sis being safed, the HST load decreased from ~75A to ~53A, resulting in a battery heat up with the increased charge current. Per COP 4.27A the +BB SPA Trim relay (Battery 3) was off-lined as Battery 3’s temperature was demonstrating an increasing warming trend and was approaching 3.5 DegC, the yellow ground limit. Commanding to off-line the SPA was performed at DOY 275, 01:04 GMT via Ops Request 18303.