NASA Hubble Space Telescope Daily Report #4057

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT #4057

PERIOD COVERED: UT February 23, 2006 (DOY 054)

OBSERVATIONS SCHEDULED

ACS/HRC 10738

Earth Flats

Sky flats will be obtained by observing the bright Earth with the HRC and WFC. These observations will be used to verify the accuracy of the flats currently in the pipeline and to monitor any changes. Weekly coronagraphic monitoring is required to assess the changing position of the spots.

ACS/HRC 10752

Cycle 14 Focus Monitor

The focus of HST is measured primarily with ACS/HRC over full CVZ orbits to obtain accurate mean focus values via a well sampled breathing curve. Coma and astigmatism are also determined from the same data in order to further understand orbital effects on image quality and optical alignments. To monitor the stability of ACS to WFPC2 relative focii, we’ve carried over from previous focus monitor programs parallel observations taken with the two cameras at suitable orientations of previously observed targets, and interspersed them with the HRC CVZ visits.

ACS/WFC 10574

Witnessing Galaxy Transformation in Galaxy Groups at z > 1

The recent discover of five galaxy groups in the Lynx supercluster region offers us the exciting opportunity to observe for the first time groups in the process of collapsing into a merging pair of clusters at z > 1. Our current picture of structure formation suggests that substantial evolution of galaxy properties can occur in groups and filaments well before they enter the environs of massive clusters. However, neither current theoretical models nor observations give us a complete understanding of the relative importance of the different physical processes that control the structural and spectral transformations that occur prior to, during, and after infall into a dense environment. We propose direct observation of these newly discovered dynamically young structures in the Lynx region, in order to provide a critical benchmark in testing not only whether galaxy evolution occurs mostly prior to entry into the densest regions but will also constrain the relative importance of initial conditions in determining the fate of galaxy systems. Our analysis of these proposed ACS measurements will be complemented with an unique dataset we have already in the optical, infrared, mid-infrared, and X-ray.

WFPC2 10779

WFPC2 WF4 Temperature Reduction Test #2

A serious anomaly has been found in images from the WF4 CCD in WFPC2. The WF4 CCD bias level appears to have become unstable, resulting in sporadic images with either low or zero bias level. The severity and frequency of the problem is rapidly increasing, and it is possible that WF4 will soon become unusable if no work-around is found. The other three CCDs {PC1, WF2, and WF3} appear to be unaffected and continue to operate properly. This is a second test to further reduce temperatures. Orbits: internal 26, external 1

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10145 – Reacq (2,1,2) drops lock @055/0927z

Reacq(2,1,2) scheduled at 055/09:19:14 reached finelock at 09:26:17 but dropped lock at 09:26:47. The Map at 09:26:28 showed errors of V1=-3.72, V2=-1.26, V3=4.55, and RSS= 6.01.

COMPLETED OPS REQUEST:

17657-1 – Increase Benchmark SOC @054/2254z

COMPLETED OPS NOTES: (None)

                          SCHEDULED      SUCCESSFUL     FAILURE TIMES
FGS GSacq                07                      07
FGS REacq                07                      06               055/0927z 
(HSTAR 10145)
OBAD with Maneuver   18                      18

SIGNIFICANT EVENTS:

Benchmark SOC Adjustment Flash Report

On DOY 2006/054 at 22:53 GMT, the EPS Benchmark SOC was successfully increased from 241A-hr to 246 A-hr via Ops Request 17657-1. EPS SE observed the expected step increase of the FSW SOC by 5 A-hr upon uplink of the new benchmark value and that the FSW SOC tracks more closely with the pressure-based SOC. The EPS system was monitored for one orbit cycle and nominal system performance was verified with the BRT satisfied ~37 minutes into orbit day and the benchmark SOC reset at 246 A-hr.