The May 2009 Servicing Mission 4 to the Hubble Space Telescope was a dramatic achievement. The astronaut spacewalks to replace, repair, and refresh the equipment on the observatory were as inspiring as they were successful. Every item on the to do list was checked off, and it is natural to ask “What’s next?”
In particular, folks want to know when the first images from the refurbished Hubble will be released.
The next step for the Hubble engineering team is called SMOV – Servicing Mission Observatory Verification. SMOV is the long process of starting up and checking out the new and repaired instruments.
Unfortunately for those impatient to see Hubble’s wonders once again, SMOV will last throughout the summer of 2009. Three of the reasons for the time required are outgassing, high-voltage, and calibration.
All materials have what chemistry calls “vapor pressure.” They release atoms and molecules, though generally in very small quantities compared to the density of Earth’s air. However, when those materials are taken to the vacuum of space, that vapor pressure becomes important.
Outgassing is the period during which the vapor pressure of the materials slowly decreases and adjusts to the space environment.
One reason outgassing is important is because the instruments use high-voltage power. Stray gases could conduct electricity and create a short. The high-voltage is slowly raised in increments and the response of the circuitry checked carefully at each stage.
Even when the instruments are operational, the calibration is painstaking. Every part of every detector must be tested and its response fully characterized. For science, it is extremely important to know how sensitive the instruments are and to be aware of the variations and anomalies in the recorded data. In short, we need to know what signals can be attributed to the instruments to figure out what signals come from the objects we observe throughout the universe.
Only when the instruments are fully operational will NASA be ready to unveil the early-release observations. I fully expect that these will be incredible new views of nebulae and galaxies, and can’t wait to see them.
But wait we must as SMOV runs its course. If things progress on schedule, the new images will be released in early September 2009.