Space Team Online QuestChat

Date: September 23, 1998

Featuring: Rick Pettegrew
Associate Staff Scientist
NASA Lewis Research Center, Cleveland, OH

[ Oran/NASAChatHost - 5 - 09:00:14 ]
Hello to our early arriving Space Team Online participants! The Space Team Online chat with Rick Pettegrew from NASA Lewis Research Center will begin approximately 30 minutes. Be sure you have read Rick's autobiography at http://quest.arc.nasa.gov/space/team/pettegrew.html before joining this chat. Once the chat begins, Rick will attempt to answer as many of your questions as he can, but please be patient. In the event that we begin to receive too many questions during the chat, the chat may be "moderated." This means that only a few questions will be posted at a time, until Rick can catch up with us. So we ask that you give Rick time to answer your questions before submitting new ones.

[ Oran/NASAChatHost - 6 - 09:01:10 ]
As a reminder, remember to enter "Your Handle" in the box provided, before posting questions to the chat room. Once you've done this, please let us know that you have logged on for today's chat.

[ Oran/NASAChatHost - 7 - 09:01:20 ]
At the conclusion of today's chat, you will have an opportunity to give us feedback about it. We encourage you to take a few minutes to share your thoughts with us by responding to our QuestChat Feedback survey at http://quest.arc.nasa.gov/qchats/qchat-surveys. Your responses, comments and suggestions will help us with future chats. We hope to hear from you!

[ Oran/NASAChatHost - 10 - 09:50:54 ]
RE: [Yoshihide/Utsunomiya_JapanBlackJack-black.jack.] Good morning Dr.Oran! I have logged on STO's Homepage.
Hello and welcome to today's Space Team Online chat with Rick Pettegrew from NASA Lewis Research Center. Rick works with a team that analyzes the characteristics and behavior of fire. Rick and his team study "the basics" of combustion science. They try to better understand the science by performing experiments in reduced gravity environments. Facilities with reduced gravity such as a drop-well, reduced gravity airplane, and the space shuttle while in space, have been used to perform their experiments. They will be sending yet another experiment into space on the future International Space Station.

[ Rick - 13 - 09:53:57 ]
RE: [Oran/NASAChatHost] Yoshihide, Rick Pettegrew is online to answer your questions.
Yoshihide- How are you?.....What would you care to talk about?

[ Rick - 15 - 09:57:13 ]
RE: [Rick] Yoshihide- How are you?.....What would you care to talk about?
Ok, Yoshihihide, let's start....are you a student? What age or grade level are you in?

[ Rick - 17 - 09:57:49 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Yes,I have a few questions for Dr.pettegrew.
Ok, shoot!

[ Rick - 19 - 09:59:23 ]
By the way, Yoshihide- Call me Rick....its a lot easier to type!

[ Rick - 21 - 10:06:56 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Good morning Dr.Pettegrew. Japanese Satellite (ETS-VII) is observing atomic oxygens in it's orbit. I heard it that atomic oxygens deteriorate a satellite body. Please tell me. Why atomic oxygens exist inte universe? and Why atomic oxygens deteriorate a satellite body?
Ok...you'll have to cut me a bit of slack on THAT particular question...I'm a combustion researcher.... As for why Oxygen exists in an atomic form, rather than its normal molecular form...my understanding is that this is rather rare. While it may be something that is being currently observed, single oxygen atoms are unstable.....because of the elctronic configuration of oxygen, it 'wants ' to bond to another oxygen atom....so the unstable "solo" atom doesnt stay that way for long!

[ Rick - 23 - 10:09:55 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Good morning Dr.Pettegrew. Japanese Satellite (ETS-VII) is observing atomic oxygens in it's orbit. I heard it that atomic oxygens deteriorate a satellite body. Please tell me. Why atomic oxygens exist inte universe? and Why atomic oxygens deteriorate a satellite body?
Now....as for why it is hard on satellite bodies..... Again, this is out of my area of expertise, but there are at least 2 effects: one is chemical interactions with the surface of the satellite; literally, "rust" (oxidation) of the surface....the other would clearly be frictional effects of the gas atom/molecule 'rubbing' on the fast-moving satellite body....but for that effect, it doesnt really matter whether its oxygen or another gas molecule...its still gonna cause friction!

[ Rick - 24 - 10:10:54 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Rick,I'm sorry. I can't write and speak English.
No problem, just do the best you can.

[ Rick - 26 - 10:14:21 ]
RE: [Rick] No problem, just do the best you can.
Yoshihide- I'm not sure if that answered your questions or not....did that make sense?

[ Rick - 29 - 10:17:45 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Thank you,Rick. I undestand Rick's responses outlines.
Ok....what else can we talk about?

[ Oran/NASAChatHost - 32 - 10:23:30 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] I will study about Rick's the researchs more than else. I'll question next time too. Please take me next chance.
Yoshihide, thank you for joining us today. Rick will be chatting with us again on Thursday, November 19. We hope you can join us at that time.

[ Rick - 33 - 10:23:45 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] I will study about Rick's the researchs more than else. I'll question next time too. Please take me next chance.
Yoshihide- No problem....it looks like I'll be back for another 'chat', probably in November. If you have some more questions now, thats fine, or if you want to join me in November, you can ask them then....

[ Rick - 36 - 10:25:15 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Thank you verry match Dr.Pettegrew and Dr.Oran!
No problem....talk to you in November!

[ Oran/NASAChatHost - 37 - 10:25:27 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Thank you verry match Dr.Pettegrew and Dr.Oran!
You're welcome, Yoshihide. Please visit http://quest.arc.nasa.gov/qchats/qchat-surveys and let us know what you thought of the chat.

[ Rick - 41 - 10:27:04 ]
RE: [MrsA-MrsA/Dist46] Hello, I'm knew to this. Are you still there?
Yes, I'm here! What can we talk about today?

[ Oran/NASAChatHost - 42 - 10:27:14 ]
RE: [MrsA-MrsA/Dist46] Hello, I'm knew to this. Are you still there?
Mrs. A., Rick Pettegrew will remain online to answer any questions you have.

[ Oran/NASAChatHost - 43 - 10:27:53 ]
RE: [Yoshihide/Utsunomiya_Japan-black.jack.] Rick and Oran,I have no question anyting today.
Thank you again for joining us today, Yoshihide.

[ Rick - 44 - 10:28:00 ]
RE: [MrsA-MrsA/Dist46] I'm hoping to get my students to interact with NASA next month. I am trying this out.
What grade level are your students?

[ Rick - 46 - 10:30:26 ]
RE: [MrsA-MrsA/Dist46] I'm not sure. I was just checking how this worked. I read your bio and am trying to see how to integrate the space challenge with our fifth and sixth grade currriculum.
Well, that's probably an age level where the kids are starting to get interested in some of these things....we can probably get a little dialog going with them that would both teach them a little, and (hopefully) keep them interested....

[ Oran/NASAChatHost - 49 - 10:32:58 ]
MrsA, we would like to obtain some general comments from you regarding your interaction with Rick Pettegrew online. Please take a few minutes to share your thoughts about chatting with us at http://quest.arc.nasa.gov/qchats/qchat-surveys. Thanks!

[ Rick - 50 - 10:33:02 ]
RE: [MrsA-MrsA/Dist46] I know you will be on for a chat again. I will try to get them to read your bio and come up with questions in advance.
Sure.....I have spoken to a variety of student groups at various schools....some of the most interest comes in the area of our 'reduced-gravity' aircraft operations, (which is how the space sequences of the movie 'Apollo 13' were filmed).....rather than "hard core" combustion science, that seems to keep kids interest, and gets them to think about some basic physics...

[ Rick - 52 - 10:36:21 ]
RE: [Rick] Sure.....I have spoken to a variety of student groups at various schools....some of the most interest comes in the area of our 'reduced-gravity' aircraft operations, (which is how the space sequences of the movie 'Apollo 13' were filmed).....rather than "hard core" combustion science, that seems to keep kids interest, and gets them to think about some basic physics...
...as I was saying, the airplane work that we do is always somewhat of a 'crowd favorite' when I speak at schools....I talk a little about that in my journal, which you should be able to find online. In that, I also talk a little about some very general science issues that pertain to our work....but I'll try to field virtually any science/space/NASA questions that they have.

[ Rick - 55 - 10:37:44 ]
RE: [MrsA-MrsA/Dist46] Thank you for your time. I will try to do some research on that area and try to get my students to observe our interaction next time. I really think this activity can be beneficial.
Great, talk to you then!

[ Oran/NASAChatHost - 56 - 10:37:52 ]
RE: [Michael-MichaelNiemack/CalTech] Hello Sorry I'm so late. Are you still there Rick?
Michael, as you know, this chat was scheduled for 9:30 a.m. Pacific Time. Rick will remain online as long as he can to asnwer your questions. He has been rescheduled to chat on November 19. We ask that in the future, you log on for chats at the time they are scheduled to begin.

[ Michael-MichaelNiemack/CalTech - 62 - 10:43:07 ]
Sorry I couldn't make it earlier. I work at CalTech and have been busy all morning.

[ Rick - 57 - 10:38:43 ]
RE: [Michael-MichaelNiemack/CalTech] If you are I was wondering what kinds of materials you use for your microgravity combustion experiments.
Michael- Glad to have you with us. As for your question....I think you mean, "what kind of fuels do we burn"?

[ Rick - 59 - 10:40:41 ]
RE: [Rick] Michael- Glad to have you with us. As for your question....I think you mean, "what kind of fuels do we burn"?
If that was your question.... we look at a lot of different fuels. Currently, I'm using thin ("thermally" thin, not just dimensionally thin) solid fuels, such as cellulosic fuel (paper), and thin plastics, such as wire insulation, etc...

[ Rick - 61 - 10:42:51 ]
RE: [Michael-MichaelNiemack/CalTech] How big are the explosions? How do the flames act differently from when you are under the influence of gravity? Do you work with possible fuel sorces for spaceflight?
Ok, several questions there.... FIRST....we try NOT to have explosions! Although an explosion IS a combustion event (generally speaking), we are looking at SLOWER occuring combustion, ie., flame spread type stuff....

[ Rick - 63 - 10:44:14 ]
RE: [Rick] Ok, several questions there.... FIRST....we try NOT to have explosions! Although an explosion IS a combustion event (generally speaking), we are looking at SLOWER occuring combustion, ie., flame spread type stuff....
Secondly, There are BIG differences between normal gravity (1-g) and reduced gravity (0-g) stuff....it looks like you are from Cal Tech, so I'll give you a slightly higher-end explanation than I would otherwise...

[ Rick - 65 - 10:45:40 ]
RE: [Rick] Ok, several questions there.... FIRST....we try NOT to have explosions! Although an explosion IS a combustion event (generally speaking), we are looking at SLOWER occuring combustion, ie., flame spread type stuff....
In (1-g), temperature differences cause BUOYANCY....which will then dominate both the mass and heat transfer processes which MUST occur for the flame to exist.....

[ Rick - 67 - 10:47:28 ]
RE: [Michael-MichaelNiemack/CalTech] Is the research mostly scientific, or how is it applied?
As far as application....the most direct (and obvious) application is spacecraft fire safety. However, we are after the fundementals of combustion, rather than after a specific application.

[ Rick - 68 - 10:48:17 ]
RE: [Rick] As far as application....the most direct (and obvious) application is spacecraft fire safety. However, we are after the fundementals of combustion, rather than after a specific application.
If you want more on this, let me know...I want to answer your questions well, but at the same time, I dont want to bore you with endless detail...

[ Rick - 69 - 10:50:13 ]
RE: [Michael-MichaelNiemack/CalTech] Re:it looks like you are from Cal Tech, so I'll give you a slightly higher-end explanation than I would otherwise. Thanks. I'm no genius, but I have a decent science background.
What else would you like to talk about?

[ Rick - 74 - 10:53:06 ]
RE: [Michael-MichaelNiemack/CalTech] Does the combustion attempt to spread as fire does in gravity, or does it self contain because of the lack of a thermal gradient? (I'm not sure if I said that right) Or does it create airflow in some other way?
Ok...good question. This can get complicated in a hurry... For the flame to exist, you have to have oxygen get to the fuel, so that it can interact with it, and combust...(I'm talking here about systems that are NOT premixed with fuel and Oxygen)...

[ Rick - 77 - 10:54:25 ]
RE: [Michael-MichaelNiemack/CalTech] Well I guess I'll have to login on time next time you do a chat to get all my questions answered. Thanks for your time though Rick. Again, I apologize for barging in so late.
Ok, actually,although that is a good question, we are starting to run a bit late....why dont you come back to my Nov 19 talk, and we'll go over the whole thing, in whatever amount of detail you like!

[ Oran/NASAChatHost - 78 - 10:54:58 ]
Thank you for joining us for our chat with Rick Pettegrew from NASA Lewis Research Center. Rick will be online to chat with us again on November 19. Check the STO chat schedule page at http://quest.arc.nasa.gov/space/chats for more information.

[ Michael-MichaelNiemack/CalTech - 81 - 10:55:58 ]
Sounds great. I promise I'll be on time for that one.

[ Oran/NASAChatHost - 80 - 10:55:56 ]
Please share your thoughts about today's "mini-chat" with us at http://quest.arc.nasa.gov/qchats/qchat-surveys.

[ Rick - 82 - 10:56:11 ]
RE: [Michael-MichaelNiemack/CalTech] I just read your last message. I'd like as much info as you can type in the next couple minutes.
Alright, (rather quickly), there are 2 main type of combustion systems: premixed, where the fuel and oxidiser are (obviously) premixed, and diffusion flames, where the fuel and oxygen are initially separated, but must then diffuse together before they react....

[ Rick - 83 - 10:58:24 ]
RE: [Rick] Alright, (rather quickly), there are 2 main type of combustion systems: premixed, where the fuel and oxidiser are (obviously) premixed, and diffusion flames, where the fuel and oxygen are initially separated, but must then diffuse together before they react....
Sorry, Michael, looks like our time is up.... Please take a look at my journal entry, and stop back in on Nov 19....we'll talk more then....

[ Oran/NASAChatHost - 84 - 10:58:37 ]
A VERY BIG THANKS to Rick Pettegrew from NASA Lewis Research Center for sharing extra time with us online today!!!