April 18, 2001 (11:05 a.m.-11:50 a.m.)

Dr. Ken Kissell, a professor at the University of Maryland and a Hubble Space Telescope scientist, chats with several classroom groups representing Grand Island Public Schools and Westside Community Schools.



Colette deFrey: Hello

Colette deFrey: The second Chat begins at 10:05!

Colette deFrey: Sorry, it starts at 11:05

Cindy Mangers: Mrs. Johnson Fourth Grade is on-line now.

Ken Kissell: http://heritage.stsci.edu

Ken Kissell: Howdy, this is Erik at the moment. We will be back and starting in just a moment.

Katie Sindt: Mra. Jensen and Mrs. Sindt's students are on and ready. Mrs. Sindt is absent, but her

students have everything they need.

Darren Folchert: Mr. Folchert's class is ready to go.

Colette deFrey: OK!

Colette deFrey: OK, I think we are ready to start.

Colette deFrey: Please wait until you are called on to enter a question

Colette deFrey: The first question will come from Mrs. Mangers class. They may sent it out now

Cindy Mangers: Dr/. Kissel, When you helped design the Hubble, what are you most proud of in

the development? Was it the most difficult part?

Colette deFrey: He says this is a great question!

Colette deFrey: Be patient! He is working on his answer now!

Colette deFrey: Remember that complete answers require some time to type in, so bear with us,


Colette deFrey: Dr. Kissell wants to give you all the best answers he can.

Ken Kissell: My job for about 5 years was to go to meetings and manufacturers plants where they

were testing the parts to ask questions and flag the problems for the NASA management.

Understanding the problem, and seeking fixes from others was the fun but tough part. The

problem I wish I had seen and solved was the the mistake in the mirror, which happened two years

before I got involved, but no one found or admitted to!

Colette deFrey: A suggestion: If you only ask the questions you had on your lists that were

submitted to Dr. Kissell, he'll be able to give faster answers!

Colette deFrey: OK, let's go with a question from Mrs. Jensen's class

Colette deFrey: Students, please have questions typed in and ready to go when called on. It will

save some time. Thanks!

Colette deFrey: How about a question from Mrs. Wroten's class then?

Donna Wroten: What are the levels of the majority of the magnification lenses on the hubble?

Colette deFrey: Good question, Dr. Kissell is in the process of answering this one.

Colette deFrey: Carol Fleming's group is next. Do not send the question until told to do so! Thanks

Cindy Mangers: Have we lost our connection? We have waited for 15 minutes and not seen


Colette deFrey: Did you get the answer to your first question?

Colette deFrey: Dr. Kissell posted it a minute or two ago

Colette deFrey: OK, back to Mrs. Wroten's question. The answer is on its way!

Ken Kissell: The Hubble uses mirrors, not lenses, to form the images. This is so all colors of light will

focus the same. The images are formed behind the second mirror and may be magnified inside

one of the science instruments by a factor of 2X to 4X. It is not like a backyard telescope where

you swap eyepieces. The image is formed directly onto aa electronic detector called a CCD, as in

a home video camera.

Colette deFrey: OK, Mrs. Flemings' group may send a question

carol fleming: Do you think the USA will send up a "Hubble 2"? If so, why and how will it have to be


Colette deFrey: He's got an answer to this one at his finger tips!

Colette deFrey: Stay tuned for the answer!

Colette deFrey: Mr. Folchert's group will be next, so be ready when I give the word. OK?

Ken Kissell: The Next-Generation Space Telescope [to be renamed after launch] is under design

right now. It will be about three times the size of Hubble, but will not take data in the UV or visible

light. It will be an infrared telescope, much less sophisticated in the instruments on-board. It will

be launched so as to travel in a looping orbit much of the way to the moon.

Colette deFrey: OK, Mr. Folcher'ts group. Go for it.

Darren Folchert: When they are finished with the Hubble are they going to destroy it and bring it

back to earth like the MIR space station?

Colette deFrey: Good question! Dr. Kissell is thinking about this one! Be patient!

Colette deFrey: http://heritage.stsci.edu

Ken Kissell: They don't know yet. They will need to visit it with the Space Shutle to do either. I

hope they bring it back for the Smithsonian Museum!!

Colette deFrey: Here's a website that Dr. Kissell sent out for the last chat.

Colette deFrey: OK, Mrs. Sindt's class is next.

Tina Rickett: How much did the HST cost to build and who paid for it?

Colette deFrey: Dr. Kissell has this answer, too!

Ken Kissell: US taxes paid 90% of $2.5 billion, European Space Agency 10%. + $250,000,000/yr

Colette deFrey: OK, let's have another question from TJ Jensen's group

Ken Kissell: The operating cost funds about 350 astronomers in Baltimare, and others who

compete with ideas for what to observe next. They have given time to high schoo; students in the


Sue Little: How does the HST know when to take pictures?

Colette deFrey: Dr. Kissell is pondering this one. Be patient!

Ken Kissell: The Hubble collects far more light with its 8-foot mirror than your eye with a

one-quarter-inch pupil, even in the dark. It brings this light into a small image at the focus of the

mirror, 20-some feet away. We don't use our eye to see the image, or film to record the image, but

instead magnify the image and put it onto an electronic detector from which it is converted into a

computer code to show the location and brightness of every detail in the small image. This is sent

back to the earth by digital radio signals for computer reconstruction.

Colette deFrey: Ok, Mrs. Wroten's class is up. Send a question please!

Donna Wroten: If the Hubble crashed and burned up in the atmoshpere, would you need more

than 4 years to build it?

Ken Kissell: The plan for use of the telescope is worked out weeks in advance. All of the next days

work is stored in the spacecraft computer, and the object found from star trackers on the outside

of the Hubble.

Colette deFrey: Dr. Kissel just thought of something he wants to add to the last answer. Here it is!

Colette deFrey: OK, he is now answering Mrs. Wroten's question.

Colette deFrey: Mrs. Flemings' students are next. But please wait until we tell you to enter the

question. Thanks!

Ken Kissell: It took 18 years to sell the idea, design, and build the last one. If we made a pure copy,

to replace it, it wouild take five years to get the money -- and five years to build it, at least.

Colette deFrey: OK, Mrs. Fleming - Go for it

carol fleming: What do you predict the Widefield Camera to be added to the Hubble in 2003 will

find, and how long do you think it will take for earth scientists to make use of the information

gathered by this camera?

Colette deFrey: Dr. Kissell has the answer to this one! It will be on the screen very shortly. Be


Ken Kissell: This will be the third camera of its class to be installed, and is the one which allows the

spectacular images of galaxies and star clusters, plus the planets and their moons. The new

camera will be more sensitive, cover about twice more sky in the UV and visible and have an

additional near-infrared imaging chip, allowing detection of cooler stars. It should allow direct

imaging of stars just in formation.

Colette deFrey: Great! Next question is from Mr. Folchert

Colette deFrey: Mrs. Sindt's students are after Mr. Folchert. But wait until I say OK to send the


Colette deFrey: OK, Mrs. Sindt, go for it!

Pam Buchholz: What are the future plan for astronomy? Is there anything currently under


Katie Sindt: What were the orignal long-rang goals for the HST?

Colette deFrey: Dr. Kissel will be answering the question from Katie Sindt right now.

Ken Kissell: It was to be used for 15 years to study the most distant objects in the universe, and to

study our companion planets and particularly the Comet Halley. [ It was launched too late to study

Halley. ] It was to be visited every 3 years to fix it and to install new instruments. It has done all

those things and now will be kept operating, barring an accident, for 20 years.

Colette deFrey: OK, T.j Jensen's students can send a qustion now

TJ Jensen: How do scientists compare radio maps with photographs taken by the HST?

Colette deFrey: Dr. Kissell is working on this one. Be patient.

Colette deFrey: Donna Wroten's students are next, but do not send until told to. OK?

Donna Wroten: How much did the clean room cost per week?

Ken Kissell: Radio maps of the sky are made by allowing the earth to rotate and scan the antennae

bean. These are plotted on a map of the heavens, simiilar to a star map. The Hubble uses stars

mapped in detail on the star map coordinates. Any data from Hubble can then be mapped against

any prior star map or radio map.

Colette deFrey: OK, how much did that clean room cost per week?

Colette deFrey: Mrs. Flemings' students are next!

Colette deFrey: But wait to enter question

Colette deFrey: I know the Merry Maids charge around $90.00 to clean a house, so a clean room

might run about 30.00????

Ken Kissell: I haven't a clue, but to build it, Lockheed took a big tax break. It was used later to built

spy satellites and communication satellites.

Colette deFrey: OK, Mrs. Fleming

carol fleming: Hi! We know a light gathering mirror was repaired by Shuttle astronauts. Was the

information lost during its down time, made up when it was repaired, or was there information lost

in a "pass by?"

Colette deFrey: s class is next

Colette deFrey: Dr. Kissell is impressed with these questions!

Colette deFrey: Katie Sindt's students have the final question for this session. Wait until I tell you to

send it! OK?

Colette deFrey: Dr. Kissell is working hard on that last question!

Colette deFrey: It has lots of different points to it.

Ken Kissell: Compared to its efficiency before the fix, the telescope could do science which was

originally planned but impossible with the fuzzy images. Infinitely better. For science which could

be done, even with fuzzy images, it was about 5-8 times faster., It only took about 1 month to fix

and adjust the repair device, which actually install 3 pairs of small mirrors, took over a year to build.

Colette deFrey: OK, Mrs. Sindt's class. We are ready for the last and final question!

Pam Buchholz: This may have been addressed, but What are your future plans for the field of

astronomy? Also, many thanks for chatting...

Donna Wroten: Thank you very much!

carol fleming: Talk about arcseconds and their impact on the work being done by the telescope.

Colette deFrey: Dr. Kissell is working on the question about future plans for the field of astronomy.

Colette deFrey: Be patient!

Ken Kissell: The Hubble telescope was a big leap forward, allowing pictures of extreme sharpness

since it eliminated the shimmer and blur of the atmosphere. It took 20 years to build it. Meanwhile,

engineers on the ground found how to use clever optics and computers at a ground based

telerscope to cancel the shimmer and blur. Wehave telescopes of more than 5 times the size of

Hubble to take much sharper picyurs than the Hubble can. I am work ing with people to study star

formation with a couple of these , one in Chile and one in Hawaii. Thanks fore asking!

Colette deFrey: All of the students in today's sessions have been very patient in waiting their turns

and waiting for their answers! A big thank you for that!

Colette deFrey: And a big thanks goes to Dr. Kissell

Colette deFrey: for sharing his expertise with us

Colette deFrey: Good bye to all. A copy of today's chat will be on the CD website!


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