NASA Hubble Space Telescope Daily Report #4207

Status Report From: Space Telescope Science Institute
Posted: Thursday, September 28, 2006



- Continuing to collect World Class Science

PERIOD COVERED: UT September 26, 2006 (DOY 269)


NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non-standard reference files available to users with a USEAFTER date/time mark. The keyword 'USEAFTER=date/time' will also be added to the header of each POST-SAA DARK frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day so each POST-SAA DARK will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such maps to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC3 10894

Probing the Birth of Super Star Clusters with NICMOS

The formation of ``super star clusters" represents an extreme mode of star formation in the local universe. Star clusters with radii < 5pc and masses exceeding 10^4 solar masses are now known to be common in starbursts. These clusters are amazingly densely packed with massive stars, and can have a violent impact on their host galaxies and the surrounding IGM. The effects of massive star clusters perhaps were even more important in the earlier universe, when galaxy mergers and starbursts were common, and the formation of massive globular clusters was ubiquitous. However, our knowledge of the formation and early evolution of such massive clusters remains poorly understood, and observations have only begun to probe these stages. The near-IR fluxes and colors of natal clusters change dramatically in their early stages of evolution, providing important diagnostics. We will use NICMOS to explore the early evolution of massive star clusters through observations of a sample of nearby starburst galaxies containing the recently discovered ultra-young massive star clusters. First identified as compact optically- thick free-free radio sources, these natal clusters are still embedded in their birth material and obscured at optical wavelengths. Sensitive, high-resolution observations in the near-IR are critical for investigating the properties of these clusters as they evolve from being completely obscured by their natal clouds to fully emerged and optically visible. NICMOS F160W, F205W, F187N, and F190N {roughly H, K, and Pa-alpha} images will allow us to determine their ages, extinctions, ionizing fluxes, embedded stellar masses, and the morphological relationship between radio, mid-IR, and optically visible clusters. These results will ultimately provide insight into the earliest stages of super star cluster evolution and the properties of massive star formation throughout the universe.

WFPC2 10745


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.

WFPC2 10914

HST Observations of Astrophysically Important Visual Binaries

This is a continuation of a project begun in Cycle 7 and continued up through Cycle 14. The program consists of annual FGS or WFPC2 observations of three visual binary stars that will yield fundamental astrophysical results, once their orbits and masses are determined. Our targets are the following: {1} Procyon {P = 40.9 yr}, for which our first WFPC2 images yielded an extremely accurate angular separation of the bright F star and its much fainter white-dwarf companion. Combined with ground-based astrometry of the bright star, our observation significantly revised downward the derived masses, and brought Procyon A into much better agreement with theoretical evolutionary masses for the first time. With the continued monitoring proposed here, we will obtain masses to an accuracy of better than 1%, providing a testbed for theories of both Sun-like stars and white dwarfs. {2} G 107-70, a close double white dwarf {P = 18.5 yr} that promises to add two accurate masses to the tiny handful of white-dwarf masses that are directly known from dynamical measurements. {3} Mu Cas {P = 20.8 yr}, a famous nearby metal-deficient G dwarf for which accurate masses will lead to the stars' helium contents, with cosmological implications. For all three stars, we will also be setting increasingly stringent limits on the presence of planetary-mass bodies in the systems.


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

HSTARS: (None)


17933-1 - Lower battery VTFE to K1L4-100mv to reduce batt. 5&6 temps

17934-0 - Monitor ACS JHAS2PWR relay

                SCHEDULED      SUCCESSFUL    
FGS GSacq          01             01                 
FGS REacq          06             06                 
OBAD with Maneuver 14             14   


1. Flash Report - VTFE Curve Adjustment Flash Report (by D. Lewis, Tue, 26 Sep 11:46:27) - On DOYs 2006/266 - 269, battery 5 and 6 temperatures exceeded their ground limit of +3.5degC during low suntime. In an effort to lower battery temperatures and thereby reduce the time required to reach the BRT setpoint of 4 batteries, EPS SEs lowered the VTFE curves on all the batteries by 100mV to a K1L4-100mV equivalent with the dog leg = 3 DegC via Ops Request 17933-1 on DOY 2006/269 at 13:51 GMT. The system was monitored for 1 full orbit day period and nominal system performance was observed. EPS SEs will continue to monitor the system and provide a more detailed analysis and plots as more data becomes available.

2. Flash Report - RE: Ops Briefing for ACS Relay State Test - Tuesday 9am (by R. Stevens, Tue, 26 Sep 06:26:12) - The briefing charts for the Relay Monitoring Test are . . . posted to the ACS Tiger Team website:

3. Flash Report - Flash Report: Ops Briefing for ACS Relay State Test including Test Results (by R. Stevens, Tue, 26 Sep 12:12:54) - The ACS HRC ASPC2 Relay Monitoring Test Ops Briefing was conducted on September 26, 2006. This is a short on-orbit test to determine the status of the HRC ASPC2 relay by monitoring the relay's state via analog telemetry. The presentation charts are posted in the EDOCS Mission Operations web-page. URL: Corrections to presentation: Chart 17: In the event of an ACS Safing, we will stand down from the test. Action Item: Steve Arslanian will brief the FOT regarding any possible out of limit conditions that may occur while the telemetry address tables are patched. Test Results: The test was run successfully on orbit. Both the ASPC1 and ASPC2 relays were reading an analog value of 171 counts (sometimes 172). ACS is currently in its Suspend Mode on Side-2.

4. Flash Report - Flash Report: SA Short Test Ops Briefing (by N. Tull, Tue, 26 Sep 15:46:18) - An Operations Briefing for the SA Sections 1 & 5 Current Anomaly Test was held on Tues, 09/26/06, at 2:00 pm in B3/S107A. Approval was granted to proceed with the on-orbit test which will investigate the source of the anomalous current signature that first occurred on 08/10/06 (2006/222, HSTAR# 10399). The test will begin on Wed, 09/27/06, at 9:16 am (2006/270/1316z). No corrections were identified. Charts are posted to EDOCS: Action Item: AI-1. If commanding is not completed on DOY 270 as planned, N. Tull will contact STScI to verify that there are no critical science activities contained in the SMS SA268Q03 intercept load that would conflict with contingency uplink opportunities on DOY 271 (Intercept time is 271/19:56:41z). AI-2. N. Tull will coordinate a follow-up meeting with HST Project to review the results of this test and other SA short analysis. Discussion/Agreements: SPA layout on SA3 is such that a short directly between two adjacent Section 1 and 5 SPAs is unlikely because the circuit panel poles are not aligned as required. However, an inter-SPA short may still be responsible for the current anomaly if a sneak path between SPAs was formed through the graphite face-sheet as a result of micrometeorite hit. EPS and Sys Mgmt can sit in MSR with the EPS Flight Controller during commanding. EPS SE and Sys Mgmt can use the HST Sim Team room to monitor CCS and work between command orbits.

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