Chat Room Transcript - Chat Session, April 3, 2008 @ 6:00 pm

<Angela Braun - NASA> good to meet you all - HAS is a GREAT
   program. i'm actually kind of jealous of you all

<Angela Braun - NASA> :)

<Gabriella Dodd> It has been really fun and I'm so looking forward to
   this summer!

<Angela Braun - NASA> it's a lot of fun.  intense, but fun

<Angela Braun - NASA> ok, well, i guess we can get started then

<Angela Braun - NASA> my name's Angela, and i work in the
   trajectory design area

<Angela Braun - NASA> basically, we tell launch vehicles how to fly

<Gabriella Dodd> So are you a flight dynamics officer?

<Angela Braun - NASA> No, but we work with the FDO

<Angela Braun - NASA> i work DOLILU

<Michael Young> How do you guys calculate everything. I mean to
   make it so exact?

<Angela Braun - NASA> day of launch i-load uplink

<Angela Braun - NASA> we send up balloons to get measurements
   of winds and atmospheric parameters

<Angela Braun - NASA> and then design a trajectory

<Angela Braun - NASA> so that the wings don't rip off!

<Michael Young> lol

<Michael Young> don't want that

<Gabriella Dodd> What kind of degree do you have?

<Angela Braun - NASA> when you're flying at several times the
   speed of sound through the thick part of the atmosphere, that can
   be an issue

<Michael Young> Does it involve tedious mathematical calculations?

<Angela Braun - NASA> aerospace engineeing BS and mechanical
   engineering MS

<Angela Braun - NASA> it probably would be tedious,

<Angela Braun - NASA> but the calculations (actually optimization
   techniques) are so difficult

<Angela Braun - NASA> we have machines do them!

<Gabriella Dodd> That's convenient!

<Michael Young> That's good!

<Angela Braun - NASA> and then we evaluate the output to make
   sure it's good

<Tehreem Bilal> ninja

<Michael Young> lol?

<Angela Braun - NASA> it's exciting, ,cause the wind is always
   changing...

<Tehreem Bilal> :)

<Angela Braun - NASA> and this kind of work is part art, part
   science

<Tehreem Bilal> is the wind speed in different layers of the
   atmosphere different?

<Gabriella Dodd> What else do you have to consider, besides the
   wind?

<Angela Braun - NASA> yes, it is

<Tehreem Bilal> you make it sound like so much fun

<Angela Braun - NASA> we also look at atmospheric temperature,
   pressure, and density

<Angela Braun - NASA> because that will effect vehicle Mach and
   dynamic pressure

<Tehreem Bilal> what effect would atmospheric pressure have on a
   launch?

<Angela Braun - NASA> which are critical parameter when
   designing steering commands

<Angela Braun - NASA> but luckily the atmosphere doesn't change
   too fast

<Angela Braun - NASA> so we only have to use one balloon for
   atmospheric parameters

<Gabriella Dodd> How much steering can you actually do at such
   high speeds?

<Angela Braun - NASA> then we evaluate the wind about every
   hour until launch time

<Angela Braun - NASA> not a lot - about 4 degrees alpha (angle of
   attack)

<Angela Braun - NASA> and we shoot for zero beta (angle of
   sideslip)

<Angela Braun - NASA> i think it's fun. cause it seems like there's
   always some sort of excitment

<Gabriella Dodd> What happens if you make a mistake in designing
   the trajectory?

<Angela Braun - NASA> losing a balloon due to icing or seeing two
   measurement systems that don't match up

<Angela Braun - NASA> well, we'd probably lose the vehicle

<Angela Braun - NASA> but luckily we're not the only team doing an
   evaluation

<Michael Young> Is there a backup incase of miscalculations?

<Tehreem Bilal> what?!

<Angela Braun - NASA> we have an independent contractor that's
   also evaluating wind effects

<Tehreem Bilal> lose, as in, gone forever?

<Angela Braun - NASA> and we have to be in agreement in order to
   launch

<Gabriella Dodd> So there's no way to save the vehicle or redirect
   the path?

<Angela Braun - NASA> plus we have pretty well-defined criteria

<Angela Braun - NASA> and margin built into the system

<Tehreem Bilal> whats your margin?

<Angela Braun - NASA> yes, lose as in gone forever

<Tehreem Bilal> !!!!

<Tehreem Bilal> scary

<Angela Braun - NASA> the aerodynamic forces would tear it apart

<Angela Braun - NASA> it is a little when i stop to think about it

<Angela Braun - NASA> but that's why we all take our job very
   seriously

<Angela Braun - NASA> tough and competent - the MOD motto

<Tehreem Bilal> i appreciate what you do so much more now. not
   that i didnt before!

<Gabriella Dodd> Yeah, it's amazing how important the people on the
   ground really are, especially when most people only think of the
   astronauts

<Tehreem Bilal> MOD?

<Angela Braun - NASA> mission operations directorate

<Tehreem Bilal> aaaaaaah

<Angela Braun - NASA> they provide all of the flight controllers and
   trajectory designers for a mission

<Michael Young> What's the toughest trajectory you have ever had
   to design?

<Angela Braun - NASA> and trainers, and simulators, and lots of
   other studd

<Gabriella Dodd> Do you also design the trajectory once the vehicle
   is in space or is there another group for that?

<Angela Braun - NASA> well, it's not exactly like that. but tough for
   us would mean a day where the winds are changing a lot

<Angela Braun - NASA> but maybe still within our tolerances

<Michael Young> oh

<Angela Braun - NASA> but you're nervous that it will change to
   bring it outside tolerances by launch time

<Angela Braun - NASA> a balloon takes an hour to rise to altitude,

<Michael Young> That's very stressing

<Angela Braun - NASA> so, we can only look at it so close to launch

<Angela Braun - NASA> for the new vehicle

<Angela Braun - NASA> we're hoping to move to a radar based
   wind measurement system

<Angela Braun - NASA> that can give us a wind profile in 5 mintues

<Angela Braun - NASA> which would be MUCH better

<Gabriella Dodd> That sounds really helpful!

<Angela Braun - NASA> (especially for those stress levels!)

<Tehreem Bilal> :)

<Angela Braun - NASA> there is a drawback though

<Michael Young> definitely!

<Tehreem Bilal> how would that radar work?

<Angela Braun - NASA> the radars can't give us as high a fidelity
   wind as balloons

<Tehreem Bilal> er...fidelity?

<Angela Braun - NASA> so we lose some info, but if we take it into
   account with design, we think we can handle it

<Angela Braun - NASA> trade study for us

<Gabriella Dodd> That makes sense

<Angela Braun - NASA> radar works by reflecting off the particles
   in the air

<Angela Braun - NASA> if you're familiar with doppler shift, same
   concept

<Tehreem Bilal> oh. that makes so much more sense than what i was
   thinking.

<Gabriella Dodd> Oh, cool! We just talked about Doppler in my
   physics class

<Angela Braun - NASA> fidelity means how accurate

<Angela Braun - NASA> balloons can give us information every 100
   ft, while radar is more like every 1000 ft

<Angela Braun - NASA> so, if you sample the wind only every 1000
   ft,, you're going to have a much "smoother" profile than if you did at
   100 ft

<Angela Braun - NASA> but it also means you're not measuring the
   "fine" movement of the wind

<Gabriella Dodd> That seems like a huge difference in precision

<Tehreem Bilal> which do you think is better? being able to measure
   the fine movement of the wind, or a more general measurement?

<Angela Braun - NASA> which, with our current design philosophy,
   drives our alpha and beta output

<Angela Braun - NASA> i think general, because the small
   movement in the wind changes very rapidly

<Angela Braun - NASA> so it's better to handle it with statistics
   rather than actual measurement

<Gabriella Dodd> And that makes things easier for the calculations,
   right?

<Angela Braun - NASA> while the gross movement of the wind
   (radar measurement) is pretty stable - doesn't change much from
   hour to hour

<Angela Braun - NASA> or if it does, would be an indication that it's
   not a good day to fly

<Angela Braun - NASA> actually, the calculations would get a little
   more complicated cause you'd be doing what you currently do,

<Angela Braun - NASA> and then adding on an additional calculation
   to compensate for small changes

<Gabriella Dodd> I didn't think about that

<Angela Braun - NASA> there will be a lot of work up front to prove
   we can do it, but once it's defined, shouldn't be too bad!

<Gabriella Dodd> How are you going to prove you can do it?

<Angela Braun - NASA> probably by using our vast database of
   Shuttle data

<Angela Braun - NASA> and proving we can make it work for that
   system first

<Gabriella Dodd> So can you practice with mock vehicles?

<Angela Braun - NASA> well, we use simulations

<Angela Braun - NASA> which for Shuttle are extremely accurate
   (about as accurate as actually flying)

….The chat got too full so a little bit is missing here!

<Angela Braun - NASA> cause the aerodynamics database turned
   out to be very different

<Angela Braun - NASA> than what was indicated in wind tunnel
   testing

<Angela Braun - NASA> but once we had flight data

<Angela Braun - NASA> they were able to update the databases and
   give better answers

<Angela Braun - NASA> well, the flight design process starts about
   a year before a given flight

<Angela Braun - NASA> with generic products used to start design
   and begin crew and flight controller training

<Angela Braun - NASA> then as we get closer and things firm up
   (like masses of payloads and such) we release updated versions

<Angela Braun - NASA> the "final" design is released about a week
   before launch

<Angela Braun - NASA> and then on launch day, my team updates it
   for environmental effects and propellant loading

<Angela Braun - NASA> or refines it, if you will

<Angela Braun - NASA> so, one of our check is agains the
   reference trajectory released about a week before launch

<Angela Braun - NASA> we have a large database of how things
   can change in that time

<Angela Braun - NASA> and if we're outside of it, we need to be
   very careful with our evaluation

<Angela Braun - NASA> just another one of the ways we make sure
   we're good to fly

<Gabriella Dodd> And if you're not?

<Angela Braun - NASA> if we're not what?

<Gabriella Dodd> good to fly

<Angela Braun - NASA> then we say "NO GO" to the Mission
   Management Team and the launch is scrubbed for the day

<Angela Braun - NASA> which nobody likes...

<Gabriella Dodd> So you just push it back to the next day?

<Angela Braun - NASA> but has happened in the past

<Angela Braun - NASA> yup - we'll usually try again the next day

<Angela Braun - NASA> unless the weather's looking bad

<Angela Braun - NASA> or we've already had a scrub, which means
   we could need to stand down for a day to reload cryogenic
   propellants

<Angela Braun - NASA> there are pages and pages of launch scrub
   Flight Rules

<Angela Braun - NASA> that tell you what to do for different
   situation

<Jonathan Hua> how many pages are you talking about?

<Angela Braun - NASA> not sure, but probably hundreds.
   althogether, there are probably thousands of pages of flight rules

<Angela Braun - NASA> luckily no one person has to know all of
   them!

<Angela Braun - NASA> which is why it's called the Flight Control
   "Team"

<Gabriella Dodd> How many are on the team?

<Angela Braun - NASA> well, you know when you see mission
   control on the tv

<Angela Braun - NASA> and there are about 20 people in the room

<Angela Braun - NASA> well, each of those people has a team of
   maybe 3 to 50 people supporting them in the "back room"

<Angela Braun - NASA> and then on top of that, there's engineering
   support in another room

<Gabriella Dodd> Wow, that's a lot more than I thought

<Angela Braun - NASA> just in case a big problem that needs to be
   worked crops up

<Angela Braun - NASA> i know, i was kind of shocked at first too!

<Angela Braun - NASA> if you just watch it on tv, it all seems kind
   of routine at this point. but, it never is

<Gabriella Dodd> That sounds really exciting!

<Angela Braun - NASA> Shuttle's still considered an "experimental"
   vehicle

<Angela Braun - NASA> it is - launch support is definitely exciting.
   and everyone has their game face on

<Angela Braun - NASA> i've never been in a room with so many
   people that's so quiet

<Tehreem Bilal> :)

<Angela Braun - NASA> before supporting space shuttle ascent

<Gabriella Dodd> I guess it's really intense

<Angela Braun - NASA> yup

<Tehreem Bilal> what is constellation by the way (sorry i asked so
   late, i had to go take a phone call)

<Angela Braun - NASA> oh, constellation is our new vehicle
   program

<Angela Braun - NASA> to replace shuttle and take us back to the
   moon and on to mars!

<Angela Braun - NASA> i can't wait to go to mars...

<Gabriella Dodd> Me neither!

<Michael Young> What exactly does it look like and does it function
   like the shuttle?

<Angela Braun - NASA> it consists of the Ares launch vehicle and
   the Orion crew module

<Angela Braun - NASA> it looks a lot like the old Apollo/Saturn V
   combo

<Michael Young> Intresting!

<Angela Braun - NASA> but taller and skinnier with a larger crew
   compartment

<Tehreem Bilal> did they use the designs from Apollo for
   constellation?

<Angela Braun - NASA> it's being designed to accomodate 6, rather
   than 3

<Angela Braun - NASA> no - while the outer mold line looks similar

<Angela Braun - NASA> all of the components are new

<Angela Braun - NASA> which i would hope so since technology's
   advanced a lot in 40 years!

<Tehreem Bilal> :D

<Angela Braun - NASA> it's funny to think

<Michael Young> Maybe those Sci-Fi spaceships will become
   reality...

<Angela Braun - NASA> that they went to the moon during apollo
   with flight computers that are probably less powerful than your cell
   phone!

<Michael Young> Wow! I didn't know that!

<Gabriella Dodd> I've heard that. Imagine what we can do now that
   we have such great technology!

<Angela Braun - NASA> maybe that's exagerating a bit, but...they
   were pretty sad. totally dwarfed by the computing power in your
   standard pc today

<Tehreem Bilal> thats hilarious, i didnt know that

<Angela Braun - NASA> i know! even shuttle has computers that
   were state of the art...for the late 70;s

<Tehreem Bilal> :)

<Angela Braun - NASA> my graphing calculator probably has more
   juice!

<Angela Braun - NASA> they have made improvements though

<Tehreem Bilal> now thats hilarious

<Gabriella Dodd> Definitely!

<Michael Young> lol

<Tehreem Bilal> improvements in capabilities right?

<Angela Braun - NASA> the shuttle computers used to have to load
   different programs off of tape before different flight phases cause it
   couldn't hold everything at once! crazy...

<Tehreem Bilal> wow

<Angela Braun - NASA> so ascent would be loaded, and then once
   they got to orbit, they'd have to load orbit software

<Gabriella Dodd> Wow, I had no idea

<Tehreem Bilal> thats a little scary

<Angela Braun - NASA> and so on

<Michael Young> man..

<Angela Braun - NASA> i know, right?

<Angela Braun - NASA> computing technology has really changed
   the game in what we do

<Gabriella Dodd> I can imagine. It's probably made your job a lot
   easier as well

<Angela Braun - NASA> even 15 years ago, the way we use our
   simulations wouldn't have been possible

<Michael Young> Are the computers at NASA more advanced than
   standard PCs?

<Angela Braun - NASA> it does, and it doesn't

<Angela Braun - NASA> now we almost have too many resources -
   so much data it can get hard to process it all

<Gabriella Dodd> Ah, that would be difficult

<Angela Braun - NASA> depends on which computers. there
   definitely are some

<Angela Braun - NASA> but we use standard dell pc's running Linux
   to run our simulations now

<Angela Braun - NASA> and we'll run them on a distributed network

<Tehreem Bilal> linux? reallY?

<Michael Young> Ooo, my dad uses linux

<Tehreem Bilal> **really

<Michael Young> personally, it's kind of hard for me to use

<Angela Braun - NASA> yup. linux. actually just finished the
   transition about a year ago

<Angela Braun - NASA> you know, you get used to it

<scott miller> does nasa have an operating system that is unique to it

<Gabriella Dodd> How much time do you actually spend on a
   computer?

<Angela Braun - NASA> i didn't know anything abotu unix/linux
   operating systems before i started working

<Angela Braun - NASA> that you even know the name of the
   technology is something! :)

<Michael Young> Heh:)

<Tehreem Bilal> :)

<Angela Braun - NASA> although, to be fair, i'm probably one of the
   least "techie" engineers out there...

<Tehreem Bilal> linux has some fun features. the guys in robotics use
   it, and it looks really cool

<Tehreem Bilal> oh-ho, trust me, you're not

<Michael Young> I heard it's safer than Windows because it's
   immune to the majority of viruses

<Angela Braun - NASA> :)

<Angela Braun - NASA> i think so, but that's just because Windows
   is so prevalent

<Angela Braun - NASA> that hacker get the most bang for their
   buck dealing with it

<Tehreem Bilal> :)

<Angela Braun - NASA> if Linux were the default system, i'm sure
   it'd have just about the same vulnerabilities

<Angela Braun - NASA> maybe more since it's open source

<Michael Young> yeah that'sture

<Michael Young> true*

<Angela Braun - NASA> not sure though. although maybe it'd get
   fixed faster

<Angela Braun - NASA> cause you have a limitless army of
   developers

<Angela Braun - NASA> :)

<Angela Braun - NASA> well, maybe not limitless...

<Gabriella Dodd> I've been wondering, what kind of hours do you
   work? I mean, do you have to put in extra time right before and
   during launches?

<Angela Braun - NASA> sometimes. depends on the launch time a
   lot

<Angela Braun - NASA> usually it's 40 hours. unless launch support
   or a big presentation or review coming up

<Tehreem Bilal> i know a night launch is really hard to do, and nasa
   did their first one recently. can you tell us about that?

<Angela Braun - NASA> or sometimes there's a question that needs
   quick turn around

<Angela Braun - NASA> well, night launch, from our perspective
   isn't that bad

<Angela Braun - NASA> it's the early morning ones that are killer

<Angela Braun - NASA> cause we have to get in about 7 hours
   before launch

<Angela Braun - NASA> so if we launch at 7 a.m. we have to work
   from midnight... :(

<Angela Braun - NASA> 3-5 a.m. is the hardest time for me...

<Gabriella Dodd> Is there an advantage to launching at night or early
   morning?

<Michael Young> wow...I can't even get up that early.

<Angela Braun - NASA> it's truly based soley on where the space
   station is

<Angela Braun - NASA> we have to rendezvous, which means we
   launch when it's orbit plane passes over the launch site

<Tehreem Bilal> :) that is so horrible. i dont like early hours, at least
   not until i've eaten something. :)

<Angela Braun - NASA> so it's totally based on orbital mechanics

<Gabriella Dodd> That makes sense

<Angela Braun - NASA> and it's cyclical - moves about 27 minutes
   earlier every day

Back to Chat Room Transcripts