Kepler Mission – Anticipating First Light
As we are counting the days for the first light detected by Kepler, what, as indicated, will happen within 10 days, some questions are popping out from the minds of those following the mission, me included. One of those questions has already been answered by Alan Gould in a previous post but I have decided to adress a request to Beyond the Cradle’s collaborator Jon Jenkins. I’ve asked the mission’s Co-Investigator, imagining how his time must be limited as the ejection of the cover approaches, if he would be available to answer some of the questions of the readers until March 26th?
Jon answered yes.
He tells us that he’s been working nearly continuously starting Friday and that the team is making real progress with commissioning, but they have barely enough time to come up for air. But the Co-I indicates us that he doesn’t mind answering questions readers pose regarding Kepler and commissioning, but he also begs for our understanding that he can’t discuss activities, events and news that hasn’t been cleared by HQ.
So please feel free to shoot your questions, you can leave them either in this post’s comment box or adress it by e-mail to beyondthecradle at gmail dot com.
In the meanwhile, as pointed out by Jenkins, the best place to find up to date new about our progress is the Kepler Mission News web page.
With my request was attached a question made by BtC’s reader “climber”:
I wonder if the cover of Kepler can be put back on, as for Hubble, so they can both protect the optic but I also wonder if, by putting the cover on, they can test again the CCD’s that will surely die during the mission so they could remove every artifact that could lead to faulse detection.
A doubt that Jon was happy to clear:
Kepler’s dust cover cannot be closed once it is deployed; in fact, it is designed to spin away irretrievably when it is released so that it does not interfere with Kepler’s view of the heavens. The dust cover is primarily intended to protect the telescope and its electronics early in Commissioning during the de-tumble and de-spin when the spacecraft separates from the 3rd stage. If the telescope slewed across the Sun and we didn’t have the dust cover, the focal plane would have been fried! A 1.4-m telescope is a really big magnifying glass trained on the CCDs.
The dust cover is not designed to be a shutter, but as long as it is in place, we can study the distribution and frequency of cosmic ray events in order to tune our cosmic ray rejection algorithm. We won’t be able to study the cosmic rays nearly as well once the cover is released and 4.5 million suns shine on the focal plane. When we reach the decision that the spacecraft avionics can avoid the Sun and we’ve completed the activities to collect dark frames from the focal plane to confirm that the instrument is functioning as expected, we will actuate the release mechanism once, and once only. We do have several sensors and on-chip measurements that can tell us if any of the CCDs or the supporting electronics have failed, so I’m not worried that we will get false positives from flakey CCDs when the cover is gone. I can hardly wait to see what we’ll see when we do release the cover!