PERIOD COVERED: 0000Z (UTC) 03/19/02 – 0000Z (UTC) 03/20/02

Daily Status Report as of 079/0000Z


1.1 Completed Five Sets of ACS/WFC/HRC 8947 (Weekly Test)

The Advanced Camera for Surveys (WFC and HRC) was used to perform
basic tests to monitor, the read noise, the development of hot pixels and
test for any source of noise in ACS CCD detectors. This program will be
executed at least once a day for the entire lifetime of ACS. There were no
problems reported.

1.2 Completed Two Sets of STIS/CCD 8906 (Hot Pixel Annealing)

The Space Telescope Imaging Spectrograph (CCD) was used to measure
the effectiveness of the CCD hot pixel annealing process by measuring the
dark current behavior before and after annealing and by searching for any
window contamination effects. In addition, CTE performance is examined by
looking for traps in a low signal level flat. There were no reported problems.

1.3 Completed NCS 8967 (Start NICMOS Cooling System)

The NICMOS Cooling System was configured to re-cool the NICMOS
detectors, to determine the optimal science operating temperature for the
NICMOS detectors, and to verify stable operation. The goals are as
follows: 1} cool the NICMOS to the coldest possible temperature as
specified by the NICMOS team {73K} with HST at a hot attitude and the NCC
compressor operating near its maximum allowable speed. 2} measure NICMOS
detector performance during the cool-down and steady state operation of the
NCS. 3} demonstrate stability {+/-0.1K} of the NICMOS detector temperature
at the optimal science operating temperature and 4} demonstrate
repeatability {+/-0.1 K} of NICMOS detector temperature following changes
from the optimal science operating temperature. All tests were successful.


2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 0

Successful: 0

Scheduled Re-acquisitions: 0

Successful: 0

2.2 FHST Updates:

Scheduled: 0

Successful: 0

2.3 Operations Notes:

The operations team continues to execute its responsibilities from

At 079/0816Z, the HST coarse attitude error is 2.46 degrees.

The NICMOS Cryo Cooler (NCC) continues operating nominally.

SSA transmitter #1 was turned on for the interval 078/1201Z to
078/1219Z, using ROP IC-2.

The SSR-1 EDAC error counter was cleared at 078/1307Z per ROP SR-1A.

As directed by an operations request, Vehicle Disturbance Test #3
(Part 3) executed nominally between 078/171000Z and 078/234000Z. This
portion of VDT #3 was executed in real-time to capture NCC surging
disturbances at the 15+ hour mark since the transition to NCC PID Operate,
at the maximum compressor speed during surging. This test was a 4-orbit
test at +V3 sunpoint. During the test interval, the fundamental NCC
surging frequency was observed to be ~1.6 Hz, and higher harmonics of the
surging frequency were also observed at integer multiples of the surging
frequency, as expected. During VDT #3 (Part 1), the fundamental surging
frequency was observed at ~3.0 Hz (within an hour of the transition to PID
Operate), and during the Vibration Emittance Ground Test, the fundamental
surging frequency was observed at 3.5 Hz (within seconds of the transition
to the maximum surging frequency). These results are all consistent with
nominal operation of the NCC during cooldown, as the fundamental NCC
surging disturbance frequency drops as the system temperature drops. As
the NCS cools, the NCC surging frequency and its harmonics are sweeping
through HST system modal frequencies, resulting in HST dynamic responses
that allow identification of the various structural modes of the
telescope. The modal properties of HST will be used to assess attitude
control law stability margins.

Using ROP 09A, the telemetry format was changed at 078/2326Z.

The following operations notes were performed during this
operational day:

  • FGS HV Monitoring during the NCS activities
  • Coarse Attitude Determination during NCS Fill Operations
  • FHST 2 Mounting Bracket Limit Change and Monitoring
  • Continue FGS HV Monitoring until ACR3 Activation


Continuation of Servicing Mission Orbital Verification and the
gradual resumption of normal science observations and calibrations.