Status Report

NASA Hubble Space Telescope Daily Report #4173

By SpaceRef Editor
August 9, 2006
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NASA Hubble Space Telescope Daily Report #4173
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT # 4173

PERIOD COVERED: UT August 08, 2006 (DOY 220)

OBSERVATIONS SCHEDULED

ACS/WFC 10546

The filaments of NGC1275

The spectacular H-0alpha filaments stretching over 100 kpc around the central galaxy in the nearby Perseus cluster of galaxies, NGC1275, resemble those found around distant radio galaxies and some protogalaxies. The origin and ionization of the filaments are poorly understood and relate to heating and cooling processes in galaxy formation and evolution. We propose here to image the filaments in order to reveal their true small-scale structure and to search for clumps of young stars along them. The observations will produce the first deep high resolution images of the whole filament system and, with our 1 Ms Chandra image, constrain both particle and photon ionization models for its ionization and excitation.

ACS/WFC 10787

Modes of Star Formation and Nuclear Activity in an Early Universe Laboratory

Nearby compact galaxy groups are uniquely suited to exploring the mechanisms of star formation amid repeated and ongoing gravitational encounters, conditions similar to those of the high redshift universe. These dense groups host a variety of modes of star formation, and they enable fresh insights into the role of gas in galaxy evolution. With Spitzer mid-IR observations in hand, we have begun to obtain high quality, multi-wavelength data for a well-defined sample of 12 nearby {<4500km/s} compact groups covering the full range of evolutionary stages. Here we propose to obtain sensitive BVI images with the ACS/WFC, deep enough to reach the turnover of the globular cluster luminosity function, and WFPC2 U-band and ACS H-alpha images of Spitzer- identified regions hosting the most recent star formation. In total, we expect to detect over 1000 young star clusters forming inside and outside galaxies, more than 4000 old globular clusters in

>40 giant galaxies {including 16 early-type galaxies}, over 20 tidal

features, approximately 15 AGNs, and intragroup gas in most of the 12 groups. Combining the proposed ACS images with Chandra observations, UV GALEX observations, ground-based H-alpha imaging, and HI data, we will conduct a detailed study of stellar nurseries, dust, gas kinematics, and AGN. FGS 10611

Precise Distances to Nearby Planetary Nebulae

We propose to carry out astrometry with the FGS to obtain accurate and precise distances to four nearby planetary nebulae. In 1992, Cahn et al. noted that “The distances to Galactic planetary nebulae remain a serious, if not THE most serious, problem in the field, despite decades of study.” Twelve years later, the same statement still applies. Because the distances to planetary nebulae are so uncertain, our understanding of their masses, luminosities, scale height, birth rate, and evolutionary state is severely limited. To help remedy this problem, HST astrometry can guarantee parallaxes with half the error of any other available approach. These data, when combined with parallax measurements from the USNO, will improve distance measurements by more than a factor of two, producing more accurate distances with uncertainties that are of the order of ~6%. Lastly, most planetary nebula distance scales in the literature are statistical. They require several anchor points of known distance in order to calibrate their zero point. Our program will provide “gold standard” anchor points by the end of 2006, a decade before any anticipated results from future space astrometry missions.

WFPC2 10745

WFPC2 CYCLE 14 INTERNAL MONITOR

This calibration proposal is the Cycle 14 routine internal monitor for WFPC2, to be run weekly to monitor the health of the cameras. A variety of internal exposures are obtained in order to provide a monitor of the integrity of the CCD camera electronics in both bays {both gain 7 and gain 15 — to test stability of gains and bias levels}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. These also provide raw data for generating annual super-bias reference files for the calibration pipeline.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10395 – GSAcq(1,3,3) requires two attempts to achieve CT-DV @ 214/1006z

OTA SE review of PTAS processing data revealed that GSAcq(1,3,3), scheduled for 214/10:06:40 required two attempts to achieve CT-DV on FGS1.

10396 – GSAcq(1,3,3) requires two attempts to achieve CT-DV @ 216/0605z

OTA SE review of PTAS processing data revealed that GSAcq(1,3,3), scheduled for 216/06:05:06 required two attempts to achieve CT-DV on FGS1.

10397 – REacq(2,1,1) failed to RGA Control @ 220/1515z

At acquisition of signal 220/15:42:39, Target REacq(2,1,1) scheduled at 220/15:15:45-15:23:50 was observed to have failed to RGA Hold due to both scan step limit exceeded (QF2SSLEX) and stop flag (QF2STOPF) on FGS-2. Prior REacq at 220/13:40:00 using the same star id was successful. At AOS Pre-acquisition OBAD2 had (RSS) attitude error correction value of 5.20 arcseconds. Post-acquisition OBAD/MAP not scheduled.

10398 – REACQ(2,1,1) failed, scan step limit exceeded on FGS 2 @ 220/2007z

REACQ(2,1,1) at 220/20:04:15 failed due to scan step limit exceeded on FGS 2 at 20:07:28. Initial GSACQ(2,1,1) and 4 previous REACQ’s were successful. REACQ(2,1,1) at 220/21:40:11 failed due to scan step limit exceeded on FGS 2 at 21:43:24. Same target and guide stars as previous failure at 20:07:28.

COMPLETED OPS REQUEST:

  • 17873-1 – Batt 1 Cap: Conting – Off-line -BB SPA (SA Sect 5) @ 220/1346z
  • 17886-0 – Contingency**** Extend Trickle Charge Elapse Timer by one orbit @ 220/1742z
  • 17886-0 – Contingency**** Extend Trickle Charge Elapse Timer by one orbit @ 220/1945z
  • 17881-0 – Genslew for proposal 10539- slot 7 @ 220/2200z
  • 17882-0 – Genslew for proposal 10539- slot 8 @ 220/2202z
  • 17883-0 – Genslew for proposal 10539- slot 9 @ 220/2203z
  • 17884-0 – Genslew for proposal 10487- slot 10 @ 220/2204z
  • 17885-0 – Genslew for proposal 10487- slot 11 @ 220/2205z

COMPLETED OPS NOTES: (None)

                         SCHEDULED      SUCCESSFUL 
FGS GSacq               04                    04 
FGS REacq               11                    08 
OBAD with Maneuver  30                    30 

SIGNIFICANT EVENTS:

As battery 5 and 6 temperatures exceeded 5.5 DegC, the -BB SPA trim relay on SA section 5 was off-lined (disconnected in hardware and masked in FSW) per the Battery Heat-Up Contingency at approximately 2006/220 13:40 GMT (8:40 am, August 8th) via Ops Request 17873-1. The battery 5 temperature decreased ~1.5 DegC the next orbit. However, only three batteries reached charge cut-off and BRT was not satisfied for the 2 orbits following taking the SPA off-line. To mitigate an unnecessary safemode entry and since the system was not in a run-down state, the Trickle Charge Elapse Timer Limit was extended from 4 orbits to 5 orbits via Ops Request 17886-0 at approximately 2006/220 17:42 GMT (1:42 pm local). By the tail end of the 3rd orbit, the EPS system satisfied BRT with 4 batteries reaching cut-off. The system also reached cut-off during the next orbit. As such, the Trickle Charge Elapse Timer Limit was restored from 5 orbits to 4 orbits at approximately 2006/220 19:45 GMT (3:45 pm local). Battery 5 and 6 temperatures continue to cycle well below 5.5 DegC. The EPS system is performing nominally.

SpaceRef staff editor.