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!

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  1. I would like to make one point on the “direction to new star fields”. No way!! Up to now only gas giants and planets obiting pulsars have been seen. Some gas giants are closer to their star than Mercury.

    This is an artifact of out obervation. Kepler, if it stares for a full JOVIAN year at the same stars could help to answer this question. We could start to get some idea of the true distribution of distances wrt. both rocky planets and gas giants.

    • Eric
    • March 18th, 2009

    Jon,

    I’m curious to know if Kepler might be repointed at some future time.

    Imagine if Kepler is very successful its first 3 years and finds 100 Earth-size planets. Then during year 4 Kepler finds 2 such planets, leading us to believe that year 5 would probably be even less fruitful.

    During years 5 and 6 (or perhaps earlier) might Kepler be pointed at some other star cluster?

    Thanks.

    • Greg Hullender
    • March 17th, 2009

    Will any of the raw data be made available for enthusiastic amateurs to play with? Several aspects of the problem of sorting out small planets from large ones from binaries from random cosmic rays etc. seem tailor-made for various machine-learning algorithms, and it would be interesting to see how well those performed in practice.

    Along those things, what sort of algorithms are you planning to use for this?

    –Greg

    • Jose Miguel
    • March 17th, 2009

    First of all thanks for taking some of your precious time to answer some of our questions, recently i was at nasa´s site watching the pages of the SIM lite mission and at some place(on SIM´s book) i read:
    “The candidate Earth-like planets revealed by Kepler will raise the question: Are they really Earths?
    Instead, they could be grazing-incidence eclipsing binaries with a brighter third star that dilutes the
    photometric dimming. SIM Lite offers a valuable way to check some of these potential false-positives.”
    Is there a way to eliminate this false positives with the current instruments,so that we can be truly sure that we have a planet?
    Thanks

  2. The Press kit mentioned a possible prolongation of the mission beyond 3.5 years. I guess (technically = excluding budget reasons) this will depend on the amount of coolant or the life time of the coolant radiator? Any other points that could influence a possible extension?
    Philip

    • imipak
    • March 16th, 2009

    Hi Jon,

    Great to see the launch and checkout seem to be proceeding well, many thanks for finding some time for us during this intensely busy period.

    I have a question about the mission duration. The primary mission’s 3.5 years and I’ve seen mention of the possibility of a secondary mission of the same length. With the experience of the MERs, Cassini’s latest extended mission and even the Ulysses spacecraft’s improbable survival months after frozen hydrazine lines were expected to end it, I wonder what the hard limits are on Kepler’s long-term survival? How long will consumables for position-holding last, for instance, and is there any prospect of getting useful science data beyond that point? Thanks!

  1. March 21st, 2009

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