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SIRTF Mission
Overview Answer Board
Andrew from
Knoxville, Md
What kind of telescope is going
to be sent into space with this
infrared technology? Is it similar
to the Hubble? |
| Well
Andrew the telescope is similar
to the Hubble in that it has
a primary mirror, a secondary
mirror, and an instrument suite
behind the primary mirror to
which the beam is directed.
The main differences from the
Hubble are firstly it is made
of beryllium rather than glass,
which the Hubble is made of.
Secondly, it’s cooled
through the cryogenic system
that you’ve heard about
to a temperature of about 1-½
degrees Calvin. And the third
difference is it’s only
about a tenth of the area or
a third of the diameter of the
Hubble, but we expect to achieve
scientific results as exciting
as those achieved by the Hubble
because we are exploring a different
part of the electromagnetic
spectrum. |
Jenny
from Las Vegas
How far will SIRTF be positioned
from Earth? |
| Well
Jenny, SIRTF will not be positioned
at a particular location relative
to the earth; it will drift
away from the earth at a distance
of at about a tenth of an astronomical
unit per year. That’s
about one tenth of the distance
from the earth to the sun. So
you can imagine as I said in
my earlier clip, SIRTF following
the earth around the sun like
a faithful puppy dog, but lagging
behind it by about a tenth of
an astronomical unit per year.
At the end of our mission we
will be about a half or six
tenths of an astronomical unit
from the earth.
Host: What
size is this observatory?
Guest: That is a very good
question Tiffany; the telescope
is about 85 centimeters in
diameter. The whole observatory
with the telescope, the instruments,
and the spacecraft is about
15 feet tall and weighs about
a ton.
|
kristin from
mooresville
How long will SIRTF be in space? |
| Well
SIRTF will be in space for a
real long time, essentially
it will be in space forever,
but we will only be using it
for our prime cryogenic mission
for 2 ½ to perhaps 6
years depending on exactly how
well the cooling system performs.
Following that we might operate
for several more years as a
mission using only our shortest
wavelength detectors because
when we’re out there in
space once we run out of cryogen,
it’s still real cold and
we’ll still be able to
do interesting science with
parts of the instrument package.
But following the cryogen exhaustion,
SIRTF will continue to orbit
the sun that you can think about
it as sort of a small asteroid
in a peculiar orbit.
Host: What would you say that you actually turn on,
on SIRTF sort of, when you start trying to get data
from it?
Guest: Well it’s kind
of a staggered or graduated
process because the telescope
cools down and the full scientific
payload can’t be exercised
until the telescope reaches
its operating temperature
about 45 days after launch.
So about 35 days after launch
we’ll complete the focusing
of the telescope. About 60
days after launch we’ll
have completed the validation
or check out of the function
element of the observatory.
And then the following month,
the third month of the mission
will be devoted to tuning
up the scientific measurement
modes and so fourth. We hope
to release the first science
data at a press conference
in mid December.
|
Richard
from Safety Harbor
How will the data be processed
and output? How soon will it
be available to the public?
|
| Well Richard,
the data will be down-linked from the spacecraft twice
per day through the capabilities of the deep space network.
And those raw data frames, if you like, will be sent to
the SIRTF science center on the Cal. Tech campus, which
will process them using specialized data processing pipelines.
The data will start becoming available to the public with
the press conference that I mentioned at about mid-December
and following that we expect to have a continuous stream
of data products available to the public through the SIRTF
science center website. And the URL for that I should
say is www.SIRTF.Caltech.edu. And if you were to go over
there now, or after you finish watching this video, you’ll
find a lot of interesting information about the SIRTF
mission, a personality profile, educational activities,
and lots of good scientific information on which I’m
sure you would enjoy looking at. |
Geoff from
Buies Creek
What will SIRTF detect? |
| Well Geoff,
we are expecting it to detect objects from the outer regions
of our Solar System in the so-called Kuiper belt objects
orbiting beyond Neptune through regions in the local universe
where stars are forming, looking at brown dwarfs, cold
objects which have never quite made it to stars but are
still visible in the infrared because their heat is diffusing
our way. Then beyond our galaxy we will be looking at
distant galaxies that are in the throws of active bursts
of star formation, galaxies that are powered by accretion
on the black holes. And at the earliest and most distant
galaxies that we can see maybe a few burning years after
the origin of the universe and the big bang. Now those
are the things that we know we can see, but equally exciting
as Dave was saying earlier, is the fact that SIRTF’s
measurement capabilities are so powerful compared to what’s
been available in the past. And we have every expectation
of making new discoveries, so the things that we’re
going to see that are going to be the most interesting
from many points of view I can’t describe for you
yet. |
Juan
Rodriguez from Gijon, Spain
The Universe has been studied
by some infrared space observatories,
like ISO or IRAS...Are you expecting
any special discovery with SIRTF? |
| Well
let me take a second Juan to explain about ISO and IRAS.
IRAS was the pioneering infrared space observatory. It
was a joint US, UK, and Netherlands project, which flew
in 1983 and surveyed the entire sky in the infrared. It
also demonstrated many of the technologies that were used
on the subsequent observatories. ISO, the Infrared Space
Observatory, was a project of the European Space Agency
operated from about 1993 to 1996 or 1995 to 1998; I’ve
forgotten the details. It was a very good mission; it
had a flexible instrument package like SIRTF does. It
followed up on many of the results from IRAS and had lots
of exciting scientific results for the European and the
US communities. And these two observatories together set
the stage for SIRTF. SIRTF goes beyond either by using
the powerful infrared detector rays that I talked about
earlier. So we’re definitely expecting to build
on their discoveries, but to go beyond we’re looking
further into space with higher sensitivity and making
new discoveries with the type I just talked about. So
it’s an evolution and beyond where SIRTF leaves
off future missions will take on in the coming years.
Host: Mike I mentioned earlier in your intro 26 years
on this project, this is probably like your baby. How
are you feeling now, I mean we’re days away from
launching?
Guest: My feelings I would say are a combination of
pride and anticipation. I’m proud of the work
that we’ve done as a group and that Dave and I
have directed to work as a team of scientists, engineers,
and managers with the support of Headquarters to build
a really beautiful instrument. It’s beautiful
to look at and it’s beautiful in terms of what
it can do. So that is very satisfying, but of course
I am really anticipating now the excitement and the
satisfaction of seeing the scientific results start
to come back and I should have said in answer to your
earlier question, we’ll know within a few weeks
that we’re good to go for the science program,
which I talked about. It will just take a few months
to get things tuned up so that we can start producing
useful scientific data.
|
Carl
from Portland
Is the SIRTF aimed at the earth
or into the vast darkness of
space and other planets? |
| Well Carl,
we can’t really look at the earth with SIRTF because
the earth is too bright. So we’ll be looking mainly
outward starting with objects in our own solar system
like Kuiper belt objects, comets, and so fourth; and then
beyond that into the galaxy and beyond. |
Carlos
from Mexico City
Will the new telescope aid in
the quest to uncover black holes?
|
| Well we
will definitely be looking at objects that are powered
by black holes. A black hole of course is a dense region
in space from which nothing can escape. But you can study
black holes by seeing their influence on material that
is very close to them, in what’s called an accretion
disk. Accretion disks will have a signature in the infrared
that may allow us to infer their properties even though
they might be in a region where there’s a lot of
dust and gas that can’t be probed as effectively
at visible or ultra violet wave lengths. So we’ll
definitely be on the track of black holes and understand
how their properties and abundance so to speak vary with
cosmic time. |
Debbie
from Melbourne
How will the data obtained be
used with the data already coming
from Hubble and Chandra? |
| Well Debbie,
these three observatories probe different regions of the
electromagnetic specter, and that’s different regimes
or different physical processes. There is an awful lot
of synergism between Hubble, Chandra, and SIRTF and perhaps
the best way to describe it is to say we’ll be doing
our deepest surveys, our most penetrating looks back into
space and time, in the same regions in space, which have
also been studied by Hubble and by Chandra. So we’ll
have a kind of panchromatic or broad view of say the properties
of distant galaxies, where Chandra looks primarily at
the hottest gas and most uniquely at the regions powered
by black holes. SIRTF might look at hidden star formation
and at the star formation, the properties of the stars,
which formed over the lifetime of the galaxy. And the
Hubble might be looking at current, ongoing star formation
and massive young stars and it’s sort of the morphology
in a way that’s not possible with SIRTF. There will
be a tremendous amount of synergism and it’s exciting
to be joining our sister great observatories. |
bill
c from york me
How will we benefit from this
upcoming launch? |
| Well Bill,
that’s a very insightful and legitimate question
because after all you’re helping to pay for this.
And I think there are a number of ways, but I think perhaps
the best answer is to say that SIRTF is another step in
man's ongoing quest to understand the universe around
us. We all benefit from the insights, the understanding,
and the marvels that NASA’s space program returns
to us. They illuminate our life on a daily basis and give
us a better understanding of the universe that we live
in. In addition, the technology that’s been developed
for SIRTF has applications in daily life in things ranging
from fire fighting, from thermal engineering, and also
even in quality control for semi-conductor chip fabrication.
And finally, SIRTF is a training ground on the one hand
for future scientists and engineers, but on the other
hand astronomy is a very accessible science and SIRTF
will help inspire future generations of students and help
them serve as a good tool for enhancing their understanding
of science even if they are going into other careers,
which is extremely important. It is very important for
all of us that we have a scientific, literate and aware
public and SIRTF will be a step towards achieving that.
So there are benefits to scientists, there are benefits
to the general public, there are benefits in specific
industrial applications, and there are benefits to mankind. |
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Curator:
NASA Official:
Web Development: JBOSC Web Development Team
Last Updated:
August 26, 2003
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