Over the course of Hubble's 20-year mission, new and improved instruments are periodically installed in order to bring the most advanced instrument technologies to the observatory.
The following chart shows how the complement of instruments aboard Hubble is evolving
over the life of the observatory.
Hotspots within the chart link to short descriptions of the instruments within this page.
Note: Tasks that do not involve the scientific instruments are not included below.
Object Spectrograph - First-generation spectrograph. FOS
was used to obtain spectra
of very faint or faraway sources. FOS also had a polarimeter
for the study of the polarized light from these sources.
Object Camera - First-generation imaging camera. FOC was used to image
very small fields of view and very faint targets.
Speed Photometer - First-generation photometer. This instrument
was used to measure very fast brightness changes in diverse
objects, such as pulsars. It was removed during the first servicing mission
in 1993 to make way for COSTAR.
Guidance Sensors - Science/guidance instruments -
The FGS's are used in a "dual-purpose" mode serving to lock
on to "guide stars" which help the telescope obtain the exceedingly
accurate pointing necessary for observation of astronomical
targets. These instruments can also be used to obtain
highly accurate measurements of stellar positions.
1993 Servicing Mission 1 (STS-61):
Field Planetary Camera 2 - Second-generation imaging camera.
WFPC 2 is an upgraded version of
which includes corrective optics and improved detectors.
Optics Space Telescope Axial Replacement - Second-generation
corrective optics. COSTAR is not an actual instrument. It consists
of mirrors which refocus the abbreviated light from Hubble's
optical system for first-generation instruments
It replaces the first-generation photometer
1997 Servicing Mission 2 (STS-82):
Telescope Imaging Spectrograph - Second-generation spectrograph/imager.
STIS is used to obtain high resolution spectra.
STIS has the special ability to simultaneously obtain spectra
from many different points along a target.
It replaced the first-generation spectrograph
Infrared Camera/Multi-Object Spectrometer - Second-generation
imager/spectrograph. NICMOS is Hubble's only near-infrared (NIR)
instrument. To be sensitive in the NIR, NICMOS must operate
at a very low temperature, requiring sophisticated coolers.
Problems with the solid nitrogen refrigerant have necessitated
the installation of the NICMOS Cooler System (NCS) on
SM3B to continue its operation. It replaces the first-generation spectrometer
2002 Servicing Mission 3B (STS-109):
NICMOS Cooling System - Like
NCS is not a separate instrument
but rather a device which will allow NICMOS to continue operations
by providing mechanical cooling for the NICMOS detectors. Results
from the HOST mission indicate that the NCS will allow NICMOS to operate for
up to 5 years beyond SM3B. CLICK HERE
for a special look at the making of NCS.
Camera for Surveys - The Advanced Camera for Surveys (ACS)
is a third-generation imaging camera. This camera is optimized
to perform surveys or broad imaging campaigns.
It replaces the first-generation camera
2009 Servicing Mission 4 (STS-125):
WFC 3 -
Field Camera 3 - Fourth-generation imaging camera.
This camera will supplement
and guarantee imaging capability for Hubble after the Fourth
Servicing Mission. It replaces the second-generation imaging camera
Origins Spectrograph - Fourth-generation spectrometer. COS
is an ultraviolet spectrograph optimized for observing faint
point sources with moderate spectral resolution.
It replaces the second-generation corrective optics
has not been used since the removal of the first-generation instruments
STIS Repair - The
Space Telescope Imaging Spectrograph
was installed in February 1997. STIS stopped functioning in August of 2004
due to a power supply failure. The instrument remains in safe mode. The
attempted in-place repair of STIS during this mission will restore Hubble's
ACS Repair - The
Advanced Camera for Surveys was
installed in March 2002. ACS suffered a power supply failure in January 2007,
leaving two of its three cameras/channels dark. ACS in-place repair will
restore all three cameras to functional capacity and allow for the ability
to do deep parallel observations with other Hubble instruments.