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TESS stands for Transiting Exoplanet Survey Satellite.
The basic idea is that it’s an all-sky survey mission that will
attempt to discover new expolanets that are going to be transiting the nearest and brightest stars.
In order to do this it has to cover pretty much the entire sky
and monitor about 500,000 stars during the two-year mission.
We’re going to be focusing primarily on Earths and super-Earths
and covering full range of stellar hosts.
All the way from F5 to M5 stars.
So basically from stars somewhat warmer and larger than the sun to stars that are quite a bit cooler and smaller than the sun.
As a result of this survey we will be able to provide targets for future missions.
In fact, I think it’s fair to say that the targets that we’ll be able to establish from the TESS missions
are ones that will be a real resource for humanity for all time
because once you’ve carried out this survey and you’ve established the nearby transiting systems,
you’ve pretty much defined the ones that are going to be most useful
for future follow-up missions.
The types of follow-up missions that will be relevant—or our observations that will be relevant
are the spectroscopic things that are going—studies that are going to be possible from the coming
generation of extremely large telescopes such as the EELT that the Europeans have funded
and also the giant segmented mirror telescopes that are coming on with several different concepts
including the TMT, which would be a 30-meter class telescope that would be in the northern hemisphere
and then a 20-meter telescope that would be in the southern hemisphere by two different U.S. consortiums.
Of course, the real crème-de-la-crème for the targets
that we’re going to be looking at are going to be those that are going to be favorably positioned for JWST to survey.
So that’s the basic idea behind TESS.
To see what the implication is that this new group of sources that we will find
have for the rest of exoplanet astronomy.
This is the current discovery space that we can have.
This is a three-dimensional plot, with stellar type along this axis.
Basically, we’re talking about going from small stars at this end to large stars at this end.
This axis is planet size going from Earth-sized planets to planets that are quite a bit larger.
This scale along the vertical axis is magnitude in the range that astronomers use,
which is almost a natural log scale.
The key boundary here that is shown here is 12 magnitude.
It turns out that’s an extremely useful boundary because many of the objects that are—that have been discovered by Kepler
and the other ground-based surveys that have going and also the COROT mission from Europe are all in this region down below here.
The reason that’s an important boundary is if you do follow-up work
on objects that are at this level or fainter—so really bright stars
that are visible that you can see with your naked eye or up in this part of the chart—these
are the ones that it takes a much larger aperture to study effectively.
So basically the region that’s populated currently are those that are very difficult to observe.
The targets that TESS will provide the community
and that’s pretty and that’s why we think of this in some sense as the people’s telescope
are those that really are in the upper part of this plot.
So this is what happens with TESS and this is the situation we have without TESS.
The other thing is, in terms of thinking about the topic we’re going to cover in this part of the session.
I was reminded, sort of go back to some of the things that we had done previously
from some of our crew.
Many of the things that we’re actually trying to do with TESS
are based on the experience that our team has had working with a previous small satellite HETE-2,
which some of the people at NASA headquarters may recall.
This is a plot that actually shows the complexity index for a number of missions versus cost.
It’s a log-log plot, so there’s a lot of scatter, but the scatter is very significant.
This is from the Aerospace Corporation.
This little purple dot down in the corner,
which has a fair degree of complexity associated with it
was actually quite a ways below the trend line.
That’s something that we really want to try to achieve with TESS
and we did that by following a very rigorous KISS philosophy.
We had a small dedicated scientist and engineer mission team
that worked on this program together for the period of three years to the launch in 2000.
And then we continued to work with many members of that team for the six years of on-orbit operations.
With that having been said, in the current climate,
as we’ve learned from the other sessions and the other talks that have been given at this meeting,
the mission challenges today are much more complex
and there certainly are lessons learned that we have from these previous missions,
but on the other hand, as Roy Maizel commented in his talk with the quote from Sun Tzu, that is really an issue.
Things are going to really be more complicated.
You can’t be bound too tightly to the things we’ve learned before,
but we should try to stick with those best practices.