Help - Search - Members - Calendar
Full Version: Kepler Mission
Unmanned Spaceflight.com > Beyond.... > Telescopic Observations
Pages: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
imipak
I'm sure there's a Portuguese equivalent of the English expression: "A watched pot never boils" ... *grin*
ustrax
Yes, I know the expression...I have chosen another one for the occasion...
Barco parado não faz viagem. wink.gif
Tictactictactictac....
PhilCo126
Did anyone found a weblink with the dimensions of the 1040 kilograms Kepler Space Observatory?
ustrax
Nope...I would say 5 to 6 meters tall...
Only found the info at the mission site, with the photometer dimensions it is just a question of doing the maths... wink.gif
http://kepler.nasa.gov/sci/design/spacecraft.html

BTW, Beyond the Cradle, spacEurope's sucessor, is welcoming some members of the Kepler team, the last one was Alan Gould, here's a bit of it, revealing how this guys imagination is running wild...gotta love science... smile.gif :

"We just finished 2 days of very exciting Kepler Science Team meetings here in Cocoa Beach FL (Mon-Tue, Mar 2-3), getting ready for Friday’s launch. We’re all extremely suspenseful, elated, and hopeful all at the same time. The science discussions were fascinating and intriguing–some about all the different types of transits we might observe with different classes of stars, different sizes of planets, shapes and periods of orbits, planets orbiting eclipsing binary stars, all stimulating thoughts of strange and wonderful new worlds."

If you scroll down you will also find a piece by Edna DeVore...everything that helps passing the time is welcome... wink.gif
PhilCo126
Ben Cooper Launchphotography has amazing photos of the Kepler Space Observatory:
http://www.launchphotography.com/Kepler_cleanroom.html


for spacecraft dimensions: google --> Kepler Press Kit wink.gif
Greg Hullender
I have a "no peanuts" rule this time, though . . .

--Greg :-)
ustrax
If my time zone doesn't fail me there will be within 30 minutes (1 p.m. EST) a Kepler Mission Pre-Launch Science Briefing at NASATV.

EDITED: Speaking of hours help me here (it's always the same thing with every event...), the launch will take place in my GMT time on Saturday 03:49:57AM? Correct? Or not?... rolleyes.gif

EDITED: Stu just made me a very happy man...
http://countdown.ksc.nasa.gov/elv/
Vultur
16 hours left...

fingers crossed...
ugordan
QUOTE (Vultur @ Mar 6 2009, 12:33 PM) *
fingers crossed...

Relax. Those guys are pros.
ustrax
Great to see the attention it is getting on CNN's website...top story! smile.gif
SpaceListener
I am trying to find out about the future position of Kepler with respect to Earth. So far I have found the following info which does not satisfy me since it does not tell me about how far will be Kelper following up to Earth with a constant distance?

QUOTE
Sixty-two minutes after launch, Kepler will have separated entirely from its rocket and will be in its final Earth-trailing orbit around the sun, an orbit similar to that of NASA's Spitzer Space Telescope.

unsure.gif
remcook
My impression was that it would move further and further away from Earth.
Google is very useful:
http://redorbit.com/images/gallery/kepler/...3/41/index.html
HughFromAlice
QUOTE (SpaceListener @ Mar 7 2009, 12:13 AM) *
future position of Kepler with respect to Earth.


I went here http://kepler.nasa.gov/sci/design/orbit.html

NASA press kit is interesting - orbit info on page 14 http://www.nasa.gov/pdf/314125main_Kepler_...2-19_smfile.pdf

Kepler needs uninterrupted viewing to ensure most efficient use of observation time for planetary transits ("100,000 stars will be monitored continuously and simultaneously")!!!!! - therefore it is being put into a heliocentric orbit that trails behind the earth where earth/moon will not block the view. Also important - being further away from effects of things like earth/moon gravity, magnetoshpere etc means good stability and so better pics. Kepler's orbit will gradually fall further behind the Earth (worst case 0.5 AU after 4 years) but it will still be within communications range even after the end of the nominal mission - 3.5 years. Will probably get funding a bit longer after that.

Hope this helps.
SpaceListener
Thank you HughFromAlice. Its heliocentric orbit takes 371 days means that it will be keeping away from Earth in every year until it will meet again with Earth in very far future. biggrin.gif
ustrax
Man...Jon Jenkins back at BTC contagiated me with is emotions...if I was intending to stay calm I can't avoid to become all emotional... tongue.gif

"I’ve been waiting for this moment for 14 years. Tonight, NASA Discovery Program’s Kepler Mission will blast off at 10:48 pm from Canaveral Air Force Station taking the hopes and dreams of myself and so many other people who’ve worked so hard for so long to make this moment happen. It feels like I’m on a roller coaster on its way up to the first big hill, ka-ching, ka-ching. I can just start to see the big drop just beyond the crest of the tracks, and at launch there will be no turning back and we’ll be taken along for one of the most thrilling rides of our lives. Yesterday I watched “Magnificent Desolation” at the IMAX theater at KSC Visitor Complex. Unbidden tears formed in my eyes and flowed down my cheeks towards the end of the film. The enormity of the goals and aspirations achieved by the Apollo Program are overwhelming."
nprev
Great, moving words. I think all of us are pretty excited, but I can only imagine how the team members feel right now.

GO KEPLER!!!!!
Zvezdichko
Looks like launch was successful.
eoincampbell
Brilliant launch Kepler, (I'm Ecstatic)
Go Find 'Em
Flea on the Headlight! cool.gif
PhilCo126
Indeed, together with CoRoT a very interesting mission to look forward to...
BIS Spaceflight May 2009 will have an article on Kepler wink.gif
Stu
Gorgeous launch pics by Ben Cooper...

http://www.launchphotography.com/Kepler.html

Second one is an absolute beauty, Ben, well done! smile.gif
FrankB
I don't know about Corot... It seems it didn't gone so well with planets detections There is a new article here: http://www.cnes.fr/web/CNES-fr/7492-jour-de-chance.php
I tried to translate it with google and I am pretty disapointed:

To date, 7 CoRoT exoplanet discovered with certainty, including the smallest ever detected. This is an array of hunting already significant, but it is actually far less than what the researchers expected to discover. "We are half the planets as we had hoped" said Peter Barge. "We were so intrigued that we first thought there was a problem in detection methods. We distributed to all teams of the light curves with simulated transits to see if it was the methods of signal processing that were reviewed. But all the simulated planets had been identified ... " Another hypothesis, that of a noise, a disturbance signal which would be higher for low-light stars, often longer. "We will soon be able to better filter the residual instrumental noise on the low stars. We will see then if we find the planets expected. » " But if no new planet revealed the tip of the eclipse, it should be made to face the facts: the problem will not come from the instrument, but the stars themselves. "Maybe the planets are formed preferentially in our little galaxy" advance Pierre Barge with a smile. "Maybe the planets are formed preferentially in our little galaxy" advance Pierre Barge with a smile. The Sun and its retinue of planets and that a majority of the exoplanets detected are located in one arm of the galaxy, the Orion arm, a fairly dense area that could be more conducive to the formation of planets and other regions. But for now, this is still a hypothesis, "says the researcher.
dmuller
Does anybody know where I can find the spice kernels for Kepler? Since it's orbiting the Sun, I would want to include it on my site.

QUOTE (SpaceListener @ Mar 7 2009, 01:43 AM) *
since it does not tell me about how far will be Kelper following up to Earth with a constant distance?


It will slowly fall behind Earth as it goes around the Sun ... Kepler orbits the Sun and not Earth. To keep it at a constant distance from Earth would involve at least two major trajectory correction maneuvers, so it is much more efficient to launch it into an orbit which is similar to that of Earth
SpaceListener
I am glad to know that the launch of Kepler was stunning and succesfull in spite of the fact that there were minor problems with some delay of relaying data to space center.

BrianJ
Congratulations on a succesful launch to everyone involved with the Kepler mission.

I have two questions which someone here may be able to enlighten me on:

1. Why wasn't an L2 orbit used (similar to the forthcoming Herschel and Planck missions)? Wouldn't an L2 orbit give a longer mission lifetime?

2. If/when an exo-planet is detected, is there any way to determine the eccentricity of it's orbit (either by Kepler or by ground based observations)?

Best regards,
Brian

scalbers
Yes, the radial velocity method can determine the eccentricity...
belleraphon1

Congratulations to the mission launch team on this beautiful launch. Heart was in my mouth waiting for confirmation of Goldstone signal.

In 1991, when the pulsar planets were announced, we started writing the Book of ExoWorlds. How many pages will be added in 4 years time?

KEPLER (and COROT) will answer a question I have been wanting an answer to ever since I was old enough to understand the question. How common are Earth sized planets?

As Alan Boss has noted, we are entering the platinum age of explanetary science.

Craig



BrianJ
QUOTE (scalbers @ Mar 7 2009, 08:28 PM) *
Yes, the radial velocity method can determine the eccentricity...

Using spectroscopy/doppler shift measurements? That's possible for Earth-sized planets? Even if there's a Jupiter-sized planet in the same system(messing things up)? Wow.

I think I'll have to try to crunch some numbers on that, to get my head around it.

The more I think about it, the more amazing the process of making those measurements, and disentangling them, becomes.

Thanks.

Del Palmer
QUOTE (BrianJ @ Mar 7 2009, 07:45 PM) *
1. Why wasn't an L2 orbit used (similar to the forthcoming Herschel and Planck missions)? Wouldn't an L2 orbit give a longer mission lifetime?


I recall L2 being mentioned early on, but they descoped along the way in order to fit on a Delta II -- it's sobering to think Kepler was rejected four times before being accepted!
MahFL
We saw the launch last night in real life from our location in Orange Park, FL. The Delta 2 looked like a large firework rocket at first. Then an orange light which noticeably accelerated. We have seen the Shuttle launch several times and also I think one of the Rovers.
tasp
It would not be confirmable by the 3 observation criteria, but it would still be interesting to review Kepler light curve data for brightenings possibly due to equivalents of Kreutz sun grazers. (IIRC, some Kreutz sun grazers have been visually observed in daytime near the sun, implying a summed magnitude increase greater than the expected decrease in magnitude due to a planetary type stellar transit)



nprev
Considering that the Kreutz group is thought to have originated from the breakup of a single large object perhaps less than a thousand years ago, and that a comet's peak brightness during periastron lasts only a few days at most, I think detection of such events by Kepler are statistically unlikely in the extreme.
scalbers
QUOTE (BrianJ @ Mar 7 2009, 09:56 PM) *
Using spectroscopy/doppler shift measurements? That's possible for Earth-sized planets? Even if there's a Jupiter-sized planet in the same system(messing things up)? Wow.

I think I'll have to try to crunch some numbers on that, to get my head around it.

The more I think about it, the more amazing the process of making those measurements, and disentangling them, becomes.

Thanks.


Well I should qualify that the radial velocity method generally works for planets larger than the Earth, depending on how close they are to their parent star. I've heard radial velocity limits between .3 and 3 m/s that would depend on the brightnesss of the parent star.

http://kepler.nasa.gov/sci/capabilities.html

It can determine the eccentricity though as well as work with multiple planets to disentangle the individual signals.
scalbers
QUOTE (antoniseb @ May 22 2006, 07:02 PM) *
It seems to me that many more opportunities happen than this. We need only look at the light curve of medium to large asteroids as the Earth, or Venus, or Mars, or Jupiter transit the Sun from their locations. There must be dozens of such events per year. More if you want to look at smaller objects.


Perhaps though the light curves of the asteroids would be more influenced by their rotation compared with a star?
climber
QUOTE (MahFL @ Mar 8 2009, 03:59 AM) *
We saw the launch last night in real life from our location in Orange Park, FL. The Delta 2 looked like a large firework rocket at first. Then an orange light which noticeably accelerated. We have seen the Shuttle launch several times and also I think one of the Rovers.

Opportunity was launched at night.
An watch out next wednesday you'll enjoy Discovery's night launch too.
Lucky man.
BrianJ
QUOTE (Del Palmer @ Mar 8 2009, 01:49 AM) *
I recall L2 being mentioned early on, but they descoped along the way in order to fit on a Delta II -- it's sobering to think Kepler was rejected four times before being accepted!
Thanks Del. I'm certainly glad Kepler made the cut in the end!

Some back-of-the-envelope calculations tell me that Kepler has a max. dV of ~23m/s (assuming 12kg propellant, ISP 2000Ns/kg)
From what I can find out on the web, Herschel(direct injection to L2 halo orbit) will need ~200m/s dV (inc. safety margin). So Kepler would require ~90kg of extra propellant on board to match that.

The largest component of the Herschel dV budget seems to be for correction of launcher error. So I guess it's largely down to the accuracy required for a launch to L2 halo orbit (compared to a launch to Earth-trailing heliocentric orbit).

@scalbers: Thanks so much for the link to the Kepler/Planet Detection Methods page. That makes the limitations of the different methods quite clear. I was just wondering if a system similar to the Earth/Sun were detected, could we tell whether it was a "habitable" place (low eccentricity) or being alternately roasted and frozen every orbit (high eccentricity).

Best regards,
Brian
Mongo
QUOTE (BrianJ @ Mar 8 2009, 06:11 PM) *
That makes the limitations of the different methods quite clear. I was just wondering if a system similar to the Earth/Sun were detected, could we tell whether it was a "habitable" place (low eccentricity) or being alternately roasted and frozen every orbit (high eccentricity).

It would be possible to determine that a particular planet had a high-eccentricity orbit using only transit information (under certain viewing circumstances), but many high-eccentricity planets would not be recognized as such.

The time between successive planetary transits (combined with the primary star's estimated mass) determines the semi-major axis, while the total duration of the transit from first to last contact is determined by the "impact factor" (how central the transit is, relative to the stellar disk), the diameter of the stellar primary and the velocity of the planet while transiting in front of the star. So if the stellar parameters are reasonably well-known, a transit duration longer than that expected from a central transit of a low-eccentricity planet says that the planet must be slower (and hence farther from its primary) at that moment than expected at any time in a low-eccentricity orbit, and so its eccentricity must be high.

However, a transit duration less than the expected duration of a central transit and a low-eccentricity orbit means little, since the transit might be off-center or grazing, which would reduce its duration as well.
Syrinx
I made it out to the Kepler launch party here at NASA Ames in Mountain View, CA. After the launch, masses of people starting filing out and I was able to grab a few minutes with Dr. Tom Roellig, co-investigator for Kepler. There were a few of us pelting him with questions, some of them interesting.

- "Flea on a headlight" whatever, what's the intensity resolution? Kepler has 16-bit A2Ds.

- Kepler has an 90 megapixel digital camera. Is all that data beamed back to Earth? No, just the pixels that have a star sitting on them, about 5%. Then compression is about 2:1.

- Does a star move from pixel to pixel during measurements? No. A star will sit within one pixel with a LARGE amount of the pixel to spare.

- What if a star just happens to be right on the border of one pixel and another pixel? Kepler blurs adjacent pixels to account for this. (Not clear to me if this is accomplished in software or hardware.)

- Why is Kepler's life span just six years? Not enough fuel. Have to desaturate from time to time, no choice.

- (My question) Can we expect preliminary data to be published in May or June? Yes and no. The Kepler team will have some data and preliminary "subjects of interest" but they won't publish it. Because some media will misrepresent the data and you'll have headlines such as "30 Earths found!!!" and NASA will look bad for no reason when NASA has to clean up the mess.
scalbers
QUOTE (Mongo @ Mar 8 2009, 07:53 PM) *
It would be possible to determine that a particular planet had a high-eccentricity orbit using only transit information (under certain viewing circumstances), but many high-eccentricity planets would not be recognized as such.

The time between successive planetary transits (combined with the primary star's estimated mass) determines the semi-major axis, while the total duration of the transit from first to last contact is determined by the "impact factor" (how central the transit is, relative to the stellar disk), the diameter of the stellar primary and the velocity of the planet while transiting in front of the star. So if the stellar parameters are reasonably well-known, a transit duration longer than that expected from a central transit of a low-eccentricity planet says that the planet must be slower (and hence farther from its primary) at that moment than expected at any time in a low-eccentricity orbit, and so its eccentricity must be high.

However, a transit duration less than the expected duration of a central transit and a low-eccentricity orbit means little, since the transit might be off-center or grazing, which would reduce its duration as well.


Perhaps in principle a transit can be determined to be off-center if we time the steepness of the light curve's descent/ascent. I'm unsure though that Kepler would have the requisite time resolution.

Brian, it looks like an Earth-Sun analogue would have a few times less radial velocity than would be needed, though one might get close if the star was near and bright with lots of photons.

Syrinx, I was at a similar launch party at CU/LASP where the mission is being controlled from. I gather most of the science activity will be at Ames.
dilo
QUOTE (Syrinx @ Mar 8 2009, 09:00 PM) *
- What if a star just happens to be right on the border of one pixel and another pixel? Kepler blurs adjacent pixels to account for this. (Not clear to me if this is accomplished in software or hardware.)

Syrinx, my understanding is that star images are deliberately unfocused at sensor and their blurred images are about 7 pixel wide. This "hardware blur" offers many advantages in terms of precison and dynamic range because it reduces effect of different pixel responses and avoid fast saturation...
Take in mind that Kepler camera is not used to took real pictures ( sad.gif ) but only extremely accurate photometry of selected stars in the field.
robspace54
I am an engineer for MAG Cincinnati (formerly Cincinnati Machine) and we built a large vertical milling machine which was used as a grinder to grind the 1.4 meter diameter photometer mirror for Kepler. The U5 machine was built for L-3 Communications (Brashear) who performed the work for NASA.

So I say bon voyage to Kepler and use your mirror well! Catch a few Earth-sized objects!!!

Rob

PhilCo126
Talking about mission life time; there was already talk of a possible extension to six years, which would allow improved observations of more transits to detect smaller planets and of course finding planets in larger period orbits cool.gif

Meanwhile:
http://www.astronomynow.com/090310KeckandK...joinforces.html
HughFromAlice
QUOTE (PhilCo126 @ Mar 11 2009, 04:03 AM) *
improved observations


Ref the article: Interesting!!! Especially ..... "Furthermore, Marcy and his team can use the Keck-calculated mass and Kepler-calculated diameter to determine the planet's density". (My bolding)
Hungry4info
QUOTE (HughFromAlice @ Mar 10 2009, 04:39 PM) *
Ref the article: Interesting!!! Especially ..... "Furthermore, Marcy and his team can use the Keck-calculated mass and Kepler-calculated diameter to determine the planet's density". (My bolding)


I am unsure why you bring attention to this. Density = mass / volume, with the mass and volume of a planet, we can calculate its density fairly easily. The density of transiting planets is not unmeasured.
To name a few examples:
HD 209458 b -> ~ 0.41 g cm^-3.
HD 149026 b -> ~ 0.82 g cm^-3.
HAT-P-2 b -> ~11.9 g cm^-3.
HD 189733 b -> ~ 1.06 g cm^-3.
TrES-3 b -> ~ 0.99 g cm^-3.

And so on...
AndyG
QUOTE (Hungry4info @ Mar 10 2009, 10:46 PM) *
.
HAT-P-2 b -> ~11.9 g cm^-3.


Denser than lead? That - Jovian cores aside - doesn't seem very planet-like to me.

Andy
HughFromAlice
QUOTE (Hungry4info @ Mar 11 2009, 08:16 AM) *
I am unsure why you bring attention to this.


As I understand it (being an interested amateur) the radius of planets can only be determined from the shape of their light curves using transiting techniques. Since Kepler will be in space and has such an advanced photometer, it will be able to determine the size of planets that are even smaller than Earth. It will simultaneously observe a huge number of stars - 100,000.

Before reading the article I didn't realize that there was any radial velocity technique sensitive enough to check out the mass of such small planets. Since Keck has the capability to detect changes in radial velocity down to below 1/m sec, it is senstive enough. It will target the transit positives.

So you were right to comment!!! Currently we only know the size and and mass of a small percentage of planets - the new Planetary Society exoplanet catalogue is really useful resource. What I should have said was ...... density of (hopefully a lot of) earth like planets!!!. That's exciting. How many will be around the 5.75 gm/cc? I believe radial velocity techniques currently only estimate min mass with + ~20% error range to more heavy than estimated - worse if not in line of site.

PS - Andy - TPS catalogue gives HAT-P-2 b density ~13.37 gm/cc!! 'Super Earth' CoRoT-Exo-7b density ~11.36 gm/cc!!
SpaceListener
QUOTE (HughFromAlice @ Mar 10 2009, 04:39 PM) *
... can use the Keck-calculated mass ...

That has brought to my attention. How does the team determine its mass?
Using the mass spectometry determines it? If it is so, which of the following
method uses:

a) Vaporisation
'b)' Ionisation
c) Acceleration
d) Deflection
e) Detection


Regards,
dilo
SpaceListener, I hope you're jocking... unsure.gif
If you are able to put an exoplanet inside a mass spectrometer, you are a genius! tongue.gif
djellison
QUOTE (SpaceListener @ Mar 11 2009, 02:22 PM) *
How does the team determine its mass?


I assume by the scale of it's influence on the parent star.

Doug
PhilCo126
Correct Doug... examining the star's (periodic) radial velocity(ies) reveals the mass(es) of exo-planet(s).

AdyG --> http://en.wikipedia.org/wiki/HAT-P-2b

Multiple exo-planets:

siravan
QUOTE (PhilCo126 @ Mar 12 2009, 03:58 AM) *
Correct Doug... examining the star's (periodic) radial velocity(ies) reveals the mass(es) of exo-planet(s).


Using radial velocity technique, one can calculate m.sin(i), where m is the mass and i the orbital inclination (for one or more planets). Hence, the radial velocity only determines a lower limit on the mass. If an exoplanet is observed by both radial velocity and transit method, it means i=90 (due to seeing a transit), and that fixed the mass. Planet radius can be calculated by transit method. Therefore, using a combination of radial velocity and transit methods, it is possible to calculate the density (but neither does it alone).
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2014 Invision Power Services, Inc.