Author Topic: NASA - Transiting Exoplanet Survey Satellite ( TESS ) updates  (Read 73174 times)

Offline speedevil

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So, the cameras are capturing the supernova progression at 0.5 fps, but then through the summing action they lose that really fine time resolution.  Regardless, the images of a developing supernova at a 30 minute cadence will be really cool.  And if they somehow get lucky enough to see one in the background of the postage stamps--and thereby have images every 2 minutes--that would be awesome.
I guess it depends how much storage and processor they have free onboard.
64 megapixels for example, if you have ten prior frames stored, and have enough spare CPU to threshold every few frames to see if anything has popped up five sigma and add it to a list of areas to store postage stamps around that area at 0.5s  until it quiets down.

I am probably not awake, but am failing to find detailed instrument and computational subsystem info, and if there is any emergency low bitrate channel that could in principle give prompt alerts of interesting places to look, even if downlinking much data is prohibitive.

Offline LouScheffer

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So, the cameras are capturing the supernova progression at 0.5 fps, but then through the summing action they lose that really fine time resolution.  Regardless, the images of a developing supernova at a 30 minute cadence will be really cool.  And if they somehow get lucky enough to see one in the background of the postage stamps--and thereby have images every 2 minutes--that would be awesome.
I guess it depends how much storage and processor they have free onboard.
64 megapixels for example, if you have ten prior frames stored, and have enough spare CPU to threshold every few frames to see if anything has popped up five sigma and add it to a list of areas to store postage stamps around that area at 0.5s  until it quiets down.

I am probably not awake, but am failing to find detailed instrument and computational subsystem info, and if there is any emergency low bitrate channel that could in principle give prompt alerts of interesting places to look, even if downlinking much data is prohibitive.
There is no way that I know of to signal the ground on request of the spacecraft.   The ground needs to have an antenna pointed towards the spacecraft and listening, which is scheduled every two weeks.   Using DSN (the normal path for communications) for continuous coverage is not practical - the network is already over-subscribed, and it would be too expensive in any event.   Maybe they could hire USN or another commercial vendor, but this likely has the same problems. 

The best bet would be to build three dedicated ground stations, spaced 120 degrees apart, so at least one is always listening.   Since the spacecraft never comes closer to the Earth than 100,000 kilometers, three are enough so one is always in view.  Bit rate would be very low, since (a) these antennas cannot be huge or they would cost too much, and (b) the spacecraft does not normally have the high gain antenna pointed to Earth, so the low gain antenna would need to be used.  But it would then be possible to signal at any time.

Offline hop

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I am probably not awake, but am failing to find detailed instrument and computational subsystem info, and if there is any emergency low bitrate channel that could in principle give prompt alerts of interesting places to look, even if downlinking much data is prohibitive.
I would expect they get some low bandwidth telemetry outside of the downlink period (the NG fact sheet mentions an S band transmitter), but even if possible in theory, there's essentially zero chance significant operational or flight software changes would be made to support something like this in the prime mission. TESS was funded to find exoplanets, everything else is a bonus. Maybe in an extended extended extended mission if it really lasts for decades as some have suggested...

The 30 minute FFIs will already be a goldmine for all sorts of astronomy.
« Last Edit: 09/04/2018 05:02 am by hop »

Offline acsawdey

The best bet would be to build three dedicated ground stations, spaced 120 degrees apart, so at least one is always listening.   Since the spacecraft never comes closer to the Earth than 100,000 kilometers, three are enough so one is always in view.  Bit rate would be very low, since (a) these antennas cannot be huge or they would cost too much, and (b) the spacecraft does not normally have the high gain antenna pointed to Earth, so the low gain antenna would need to be used.  But it would then be possible to signal at any time.

Perhaps it could employ a beacon like New Horizons does during it's hibernation periods -- broadcast just a carrier wave and the center frequency tells you if it has an alert. No demodulation equipment necessary would make it easier to recruit people to check in a few times a day. Not as good as instantly, but ~8 hours notice is better than 14 days.

It does seem like on-board analysis could as speedevil suggests and dynamically add postage stamps if something new pops up between one 2-second frame and the next (and persists for the next few frames).

Offline as58

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The best bet would be to build three dedicated ground stations, spaced 120 degrees apart, so at least one is always listening.   Since the spacecraft never comes closer to the Earth than 100,000 kilometers, three are enough so one is always in view.  Bit rate would be very low, since (a) these antennas cannot be huge or they would cost too much, and (b) the spacecraft does not normally have the high gain antenna pointed to Earth, so the low gain antenna would need to be used.  But it would then be possible to signal at any time.

Perhaps it could employ a beacon like New Horizons does during it's hibernation periods -- broadcast just a carrier wave and the center frequency tells you if it has an alert. No demodulation equipment necessary would make it easier to recruit people to check in a few times a day. Not as good as instantly, but ~8 hours notice is better than 14 days.

It does seem like on-board analysis could as speedevil suggests and dynamically add postage stamps if something new pops up between one 2-second frame and the next (and persists for the next few frames).

For supernovae 2-second time resolution feels like an overkill and I doubt a supernova could be caught by analysing consecutive frames. Supernova brightening time scales are quite a bit longer than a few seconds.

Offline LouScheffer

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For supernovae 2-second time resolution feels like an overkill and I doubt a supernova could be caught by analysing consecutive frames. Supernova brightening time scales are quite a bit longer than a few seconds.
At least sometimes supernovae are associated with Gamma Ray Bursts, which can have optical transients with risetimes measured in seconds.  So two second resolution might both be useful, and could get some trigger events with inter frame comparison.

Offline deruch

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I had a chance to ask Jeff Volosin about comparing Kepler transits with TESS versions of the same planet to help calibrate analysis of both and he said NASA declined because they wanted to keep TESS on the southern hemisphere for now.
 Next year they should have a chance to get some Kepler targets with TESS for comparison.

Dr. Jeff Volosin - TESS - 21st Annual International Mars Society Convention
The Mars Society
Published on Sep 3, 2018

Dr. Jeff Volosin, NASA Goddard
Transiting Exoplanet Survey Satellite (TESS)

From the 21st Annual International Mars Society Convention, held at the Pasadena Convention Center in Southern California from Aug 23-26, 2018.

The four-day International Mars Society Convention brings together leading scientists, engineers, aerospace industry representatives, government policymakers and journalists to talk about the latest scientific discoveries, technological advances and political-economic developments that could help pave the way for a human mission to the planet Mars.


https://www.youtube.com/watch?v=KIAYb08qFrI?t=001

Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline ncb1397

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50 exoplanet candidates:

Quote
In just six weeks of science observations, NASA’s Transiting Exoplanet Survey Satellite (TESS) has already found 50 possible new worlds for scientists to examine.
http://blogs.discovermagazine.com/d-brief/2018/09/14/nasa-tess-exoplanet-spacecraft-finds-new-worlds/#.W51MuUxFy74

Offline Star One

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50 exoplanet candidates:

Quote
In just six weeks of science observations, NASA’s Transiting Exoplanet Survey Satellite (TESS) has already found 50 possible new worlds for scientists to examine.
http://blogs.discovermagazine.com/d-brief/2018/09/14/nasa-tess-exoplanet-spacecraft-finds-new-worlds/#.W51MuUxFy74

Thanks for posting that sounds like TESS is working beyond nominal which is good news for science results.

Offline speedevil

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Dr. Jeff Volosin - TESS - 21st Annual International Mars Society Convention
@17:20 'You can see the rise of a supernova and you can see it tail off. Not to get ahead of ourselves, but we're publishing in the next couple of weeks something around that' - paraphrased.
Just after that he refers again to 'usually you don't have the benefit of a camera which takes data every two seconds' - which is odd for a comment about supernova if there is no triggering on high brightness events, because if there is no fast trigger, then there is no point at all, because by the time the data is downlinked, the next opportunity to observe that spot will often be a couple of years hence, and the only frames stored would be at the low 'full frame' decimated rate.

If you have ten prior frames stored, and have enough spare CPU to threshold every few frames to see if anything has popped up five sigma and add it to a list of areas to store postage stamps around that area at 0.5s  until it quiets down.

Will be interesting to see details in the paper referred to.
« Last Edit: 09/16/2018 02:07 pm by Lar »

Offline jebbo

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Announcement of the first discovery from TESS:

TESS Discovery of a Transiting Super-Earth in the Π Mensae System

Quote
We report the detection of a transiting planet around π Mensae (HD\,39091), using data from the Transiting Exoplanet Survey Satellite (TESS). The solar-type host star is unusually bright (V=5.7) and was already known to host a Jovian planet on a highly eccentric, 5.7-year orbit. The newly discovered planet has a size of 2.14± 0.04~R⊕ and an orbital period of 6.27 days. Radial-velocity data from the HARPS and AAT/UCLES archives also displays a 6.27-day periodicity, confirming the existence of the planet and leading to a mass determination of 4.82± 0.85~M⊕. The star's proximity and brightness will facilitate further investigations, such as atmospheric spectroscopy, asteroseismology, the Rossiter-McLaughlin effect, astrometry, and direct imaging.

Paper here: https://arxiv.org/abs/1809.05967

--- Tony

Offline Alpha_Centauri

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Odd it’s been uploaded to arxiv without an official press release.

Edit: oh it’s at the EPSC.
« Last Edit: 09/18/2018 12:10 pm by Alpha_Centauri »

Offline jebbo

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It's #EPSC2018 but yes, I was a bit surprised this came out with no associated media stuff :-)

Offline ChrisGebhardt

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It's #EPSC2018 but yes, I was a bit surprised this came out with no associated media stuff :-)

This is a draft of a not-yet final paper and was not published with permission.  It's an embargo break, and not a good one either.

UPDATE on this (same as posted below).  The person who told me the paper was not published with permission was incorrect.

These are being published by the TESS team themselves so that ground telescopes can be used to quickly confirm the exoplanet candidates.

There was some initial confusion on that point as NASA is not used to operating on such quick turn-around of candidate planet info -- hence why the draft papers are hitting and becoming public hours before NASA tweets confirmation (as opposed to the usual method where NASA announces first or in conjunction with official paper publication).
« Last Edit: 09/20/2018 09:26 pm by ChrisGebhardt »

Offline JH

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Embargo breaks not withstanding, its a cool discovery, with a surface gravity of 105(+24/-22)% that of Earth. A shame that it's exposed to 318x Earth's solar flux.

Offline as58

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The paper was posted on arxiv by the first author. How does that make it "published without permission"? Or didn't she get ok from the other authors?

Offline jebbo

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I wondered about that as well. There has been some surprise about the paper, but mostly to do with publication of a discovery from data that is only available to a few beta testers from a mission with no proprietary period ... to me, the paper seems scant on detail of the data and errors properties and the detrending process - especially for a "first discovery" paper.

--- Tony

Offline Alpha_Centauri

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It does worry you when some of the most intelligent people on Earth can screw up something as simple as an embargo...
« Last Edit: 09/19/2018 05:13 pm by Alpha_Centauri »

Offline Star One

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NASA - Transiting Exoplanet Survey Satellite ( TESS ) updates
« Reply #118 on: 09/19/2018 06:51 pm »
It does worry you when some of the most intelligent people on Earth can screw up something as simple as an embargo...

They are still only human.

Anyway leak or not it has now been reported more widely.

https://gizmodo.com/nasa-s-tess-space-telescope-has-spotted-its-first-exopl-1829165207
« Last Edit: 09/19/2018 07:26 pm by Star One »

Offline jebbo

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Well, it is now official:

From @NASA_TESS on Twitter:
Quote
The @NASA_TESS team is excited to announce the mission's first candidate  planet -- a super-Earth around the bright star Pi Mensae, nearly 60 light-years away. The planet orbits every 6.3 days. The discovery is now  being reviewed by other scientists to validate it. Stay tuned!
https://twitter.com/NASA_TESS/status/1042496479108243456

--- Tony

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