NASA Hubble Space Telescope Daily Report #4094

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT #4094

PERIOD COVERED: UT April 17, 2006 (DOY 107)

OBSERVATIONS SCHEDULED

ACS/HRC 10512

Search for Binaries Among Faint Jupiter Trojan Asteroids

We propose an ambitious SNAPSHOT program to survey faint Jupiter Trojan asteroids for binary companions. We target 150 objects, with the expectation of acquiring data on about 50%. These objects span Vmag = 17.5-19.5, a range inaccessible with ground-based adaptive optics. We now have a significant sample from our survey of brighter Trojans to suggest that the binary fraction is similar to that which we find among brighter main-belt asteroids, roughly 2%. However, our observations suggest a higher binary fraction for smaller main-belt asteroids, probably the result of a different formation mechanism {evident also from the physical characteristics of the binaries}. Because the collision environment among the Trojans is similar to that of the Main Belt, while the composition is likely to be very different, sampling the binary fraction among the fainter Trojans should help us understand the collisional and binary formation mechanisms at work in various populations, including the Kuiper Belt, and help us evaluate theories for the origin of the Trojans. Calibration of and constraints on models of binary production and collisional evolution can only be done using these large-scale, real-life physical systems that we are beginning now to find and utilize.

ACS/HRC/WFC 10758

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This programme will be for the entire lifetime of ACS. Changes from cycle 13:- The default gain for WFC is 2 e-/DN. As before bias frames will be collected for both gain 1 and gain 2. Dark frames are acquired using the default gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The first half of the program has a different proposal number: 10729.

WFPC2 10748

WFPC2 CYCLE 14 Standard Darks

This dark calibration program obtains dark frames every week in order to provide data for the ongoing calibration of the CCD dark current rate, and to monitor and characterize the evolution of hot pixels. Over an extended period these data will also provide a monitor of radiation damage to the CCDs.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES:

• 17714-0 – Dump 486 ESBs @ 107/1029z
• 17716-0 – ACS cleanup after Inertial Hold @ 107/1232z
• 17717-0 – WFPC2 cleanup after Inertial Hold @ 107/1239z
• 17711-3 – Contingency: Off-line +A and -E SPA Trim Relays (COP 4.31, case 5 only) @ 107/1250z
• 17719-0 – Reset SSR-1 Storage Area 1 PB Pointer @ 107/1254z
• 17720-0 – Uplink N02Z2700D and set ATP after Inertial Hold @ 107/1336z
• 17718-0 – M2G Inertial Hold Safemode Recovery @ 107/1530z
• 17710-0 – Validate ACS FSW 4.01A Installation @ 107/1521z
• 17695-2 – Monitor VehConLaw.Integral Path Data via TMDIAG Slot 0 @ 107/1655z
• 17721-0 – Start/Stop SFD to SSR 1 @ 107/1730z
• 17722-2 – Set up NSSC memory monitors @ 108/0024z

                         SCHEDULED      SUCCESSFUL
FGS GSacq                01                    01
FGS REacq                01                    01
OBAD with Maneuver   04                    04

SIGNIFICANT EVENTS:

HST SAFEMODE: Following the Health and Safety SMS intercept at 2006/107/14:59:59, SEs verified data transmission through High Gain Antenna when data was acquired. The recovery from Inertial Hold Safemode via OR # 17718 was completed at 2006/107/15:30 GMT.

HST Spacecraft Emergency was terminated @ 107/2310z (Continued) Final Inertial Hold Flash: Science SMS Intercepted

Transition from Health and Safety SMS to Science SMS successfully occurred at 108/02:34 GMT. WFPC calibrations began around 108/04:30 GMT. Beginning of guide star acquisition was also successfully verified at 108/05:20 GMT.

Off-Line SA Section 3 SPAs Flash Report:

After lowering the VTFE curves twice to K1L4-100mV to mitigate battery heat-up during high sun-time, the battery 1-3 temperatures remained above 5 DegC. Since battery 3 exceeded 5.5 DegC, as per the second high sun-time contingency, EPS SEs off-lined one 4-string SPA (+A) and one 5-string SPA (-E) on SA section 3 via Ops Request 17711 on DOY 2006/107 at 12:48 GMT.

The system was monitored for 1 full orbit day period in the MOR and EPS SE observed nominal taper charge control performance. EPS SEs will continue to closely monitor the system.