Hubble Space Telescope

Image of Hubble Space Telescope

  • Dimensions: 13.2 x 4.2 m (43.3 x 13.8 ft)
  • Mass at Launch: 11 110 kg (24 490 lb)
  • Power: 2 800 watts
  • Launch date: 24 April 1990, 12:33:51 UTC
  • Rocket: Space Shuttle Discovery (STS-31)
  • Rocket Launch Site: Kennedy Space Center Launch Complex 39 (Kennedy LC-39B)
  • Orbit: Geocentric Low Earth Orbit
  • Orbital Distance: 539 – 543 km (335 – 337 mi)
  • Orbital Period: 1 h 35 min or 95.47 minutes
  • Velocity: 27 300 km/h or 7.59 km/s (16 990 mi/h or 4.72 mi/s)
  • Diameter of Main Telescope: 2.4 m (7.9 ft)
  • Focal Length: 57.6 m (189 ft)
  • Focal Ratio: f/24
  • Operators: NASA, ESA, STScl
  • Satellite Catalogue Number (SATCAT): 20580
  • International Designation (COSPAR ID): 1990-037B
  • Manufacturer: Lockheed (spacecraft), Perkin-Elmer (Optics)

Little about the Hubble Space Telescope

From the down of human kind we had a fascination towards night sky, and most of observations before first telescopes were made with naked eye. When in 1610 Galileo turned the telescope to heavens our as a species understanding of universe changed forever.

The telescope is named after Edwin Hubble, he discovered other galaxies beyond ours in Mt. Wilson Observatory near Pasadena, California in 1920. Hubble Space Telescope was not the first telescope above the atmosphere, but was ultimate mountaintop. The main reason to have such a powerful telescope in space was that it would escape rain clouds, light pollution and atmospheric distortions.

Hubble Space Telescope was launched on April 1990 and started new exciting discoveries in Astronomy. It received four servicing missions and more than 25 years of operation and changed how we view our universe forever.

First and seemingly fatal flaw

Image of Charles Pellerin

When you’re working in big office, you have days where it seems that whole world is against you. Charles Pellerin found himself in that situation on day when the telescope was powered up. it was clear that Hubble Space Telescope have unfixable problems with its optics.

Imagine your self in a situation like that where you need to explain to everyone that decade and half was wasted including absurd amount of money $3 billion.

“A good friend of Pellerin who worked on the telescope fell ill in the wake of the launch and died. Two of Pellerin’s senior staffers had to be removed from their offices by guards and taken to alcohol rehab facilities. “These are PhDs sitting at their desk getting drunk; this is how bad the stress was,” says Pellerin.” according to CIO portal. Pellerin was not trying to hide or runaway, instead he tried to fix Hubble and he was successful.

Flawed mirror

Within few weeks after Hubble Space Telescope was launched, first images were received.

Image proves that Hubble optics are flawed

This Extract from Wide Field Planetary Camera (WFPC) shows how light is scattered around the star in great area instead of just few pixels. This result is in pace because when the primary mirror was polished it was polished in wrong shape. Even being in wrong shape this mirror was smoothest to date, with smoothness of about 10 manometers.

Solution was ‘spectacles’

From the beginning Hubble was intended to have servicing mission, and the first one was scheduled for 1993. Astronauts began immediately seeking for potential solution to the problem. The option of bringing the Hubble to the ground for mirror refitting was to much expensive and time consuming and orbital refitting was impossible to.

The fact that the mirror was so precise (even in wrong shape) it opened an opportunity to create new component which might solve the problem. This component must be polished with the same error margin but in opposite sense.

The Corrective Optics Space Telescope Axial Replacement (COSTAR) system developed, it consisted of two mirrors in light path to correct for light aberration. To fit new component into observation where it needed to go one of original instruments had to be removed, High Speed Photometer was sacrificed. In following years all the instruments that requires the primary mirror with COSTAR had fitted with corrective optics and all that was achieved by 2002.

Hubble Servicing Missions

SM1: 2-13 December 1993

This first planned servicing mission was used mainly in attempts to rescue Hubble Space Telescope, new equipment was installed to correct for primary optics flaw.

SM2: 11-21 February 1997

With time some of observations instruments started to fail and degrade, this mission aim was to replace them with different instruments to increase Hubble’s performance and efficiency. Installation of new instruments increased space observations wavelength rage to near infrared for imaging and spectroscopy.

SM3A: 19-27 December 1999

Third mission had to be split into two separate mission just to bring Hubble to operation as soon as possible. This mission was assigned to fix Hubble’s gyros when fourth out of six stopped working and telescope went to save mode and mo more science could be done.

SM3B: 1-12 March 2002

During this mission astronauts replaced solar panels, installed new Advanced Camera for Survey. This instrument was the last original instrument in Hubble Space Telescope.

SM4: 11-24 May 2009

Cosmic Origins Spectrograph (COS) and Wide Field Camera 3 (WFC3) were installed over the corse of the last mission to Hubble. Telescope Imaging Spectrograph (STIS) and Advanced Camera for Survey (ACS) have bin failed and first on-orbit repairs had to be carried out to bring them back to life. To prolong Hubble’s life new gyroscopes, new science computer, new batteries, new isolation on three electronics bays have bin installed and refurbished fine guidance sensor. All this took 12 days and five spacewalks.

Reference list:

NASA – Hubble Servicing Missions

Wikipedia – Hubble Space Telescope facts

CIO article