01.06.2010 [T]
- Introductions, getting settled in
- Computer set-up
- IDL review
02.06.2010 [W]
- More IDL (still no official project)
- Met FIREBIRD team & had a mission briefing
- PowerPoints showing necessary steps to flight (systems
engineering)
- Got aquainted with the mechanical engineering crew in the MechE
computer lab, this is where I'll be spending most of my time
- Obtain necessary password for lab machines, document managers,
servers, etc...
- Read into a few of the current tasks-at-hand, such as:
- Space-craft deployment mechanisms: need to
controllably separate the two birds, something that has never actually
been attempted before.
- Structural/Thermal analysis
- Hysteresis rods: Help to reduce the amount of
tumbling the satellite does while constrained uniaxially, by way of a
permanent maganet located at the centroid of the craft, along Earths
magnet field lines. These are small magnetic bars (actually more
like strips) which dissipate energy, in the form of heat, exerted on
the craft due to a torque created by the magnetic field lines. **quite
interesting
03.06.2010 [R]
- More IDL (Got a Project)
- Project Goal: For an active day on the sun obtain a series of EIT
images from the online database (??) and map them with an contour
overlay of MDI data durign the same time and zoom in on a paticularly
active regaion and plot these images. (Stayed in the Coders Cavern all
day until the task was complete)
- Spent a good while just obtaining and saving the images to my
directory, the new syntax was a little confusing.
- Finally got a cool movie to play, see my homepage.
04.06.2010 [F]
- Presented my IDL project to the group.
- Read deeper into the thermal analysis.
- AFRL slide show on completing thermal analysis for a satellite
- Analysis done on other missions (SpaceBuoy, EIP)
- Decide to create an SSEL template for thermal analysis for any
satellite; use analysis from SpaceBuoy as a guide along with the AFRL
guides. The EXCEL from SpaceBuoy is great, will keep this no need
to redo.
- Get through taking all necessary notes to complete the
preliminary
thermal analysis: this assumes the craft is a sphere with a single
node, no temperature gradients allowed. Just need to type up all
the individual steps.
WEEK 2
07.06.2010 (M)
- Started the multi-node analysis reading and taking notes
- will have 1 node per structural component for a cubesat like
FIREBIRD
this will be 6 sides plus 1 for the heat generated by the
instrumentation inside of the craft.
- Temperature gradients WILL be considered at this stage
- View factors will be necessary, get messy fast! For example:
over 50
calculations for to obtain a matrix of values 11 X 11.
- Got through all of the reading
- GOAL: get templates for entire thermal/structural analysis done
by
Friday (6/11)
08.06.2010 (T)
- Typed out template for preliminary, single-node, thermal
analysis. Thouroughly explained all steps but still need a
results and conclusions section
- GOAL II: Will now complete the preliminary thermal analysis for
FIREBIRD with the rest of the week, while the material is still fresh
in mind
- Had a FIREBIRD meeting with all members of the team. At the
meeting there were a few main issues that were disscussed, mainly about
some mechanical parts that need to finish being modeled, some other
softwear issues, some criticing of the separation proposal along with
solar panel placement discussions.
09.06.2010 (W)
- Finished the results and conclusions section
- Proof-read document, and added references
- Began to obtain (dig up) the necessary design parameters such as:
mass, surface area (that occupied by the surface material and solar
panels obtain percentanges of each), internal heat generated, total
surface area, surface/solar panel properties
10.06.2010 (R)
- Finally found just about all of the necessary parameters to
complete
the thermal analysis, just have a few questions about what surface
should be initially tested, if the internal heat used is correct...
- Modified the eclipse fraction to match that of the FIREBIRD
mission
and corrected the cold-case calculations to reflect this (changed
frcation from 5/12 to 4/12 of the time spent in eclipse, as found in
the power budget)
- Had an antenna deployment brain-storm session with the head of
SSEL
and some of the other graduate students working on the project
- Pretty productive meeting, now have the basic idead that will
be
used, this is to wrap the antenna around the outside and eliminate the
possibility of mechanical faliure (the concept we came up with had too
many moving parts involved: this adds weight and sources for error,
both of wich are NO goes for satellite's)
- Had a lecture this morning about methods of viewing the sun.
Discussed
the various types of instruments to observe the sun.
11.06.2010 (F)
- meeting with Eshon to get a better direction for actually
completeing the thermal analysis for FIREBIRD
- need to reconsider the way in which the hot/cold cases are
defined. Need to create (simulate) all permutations of craft
generation levels
- PEAK: all duty cycles at 100%
- AVG: duty cycle set at operation level
- MIN: only components with 100% duty cycle on
- PEAK whole orbit
- MIN whole orbit
- AVG whole orbit
- PEAK in sun/MIN in eclipse
- MIN in sun/PEAK in eclipse
- completed the preliminary thermal analysis
WEEK 3
14.06.2010
(M)
- read through hysteresis documentation more
- simulating craft with/without the rods in either 1-D or 2-D
- have a better grasp of how to go about the analysis to determine
the necessary volume of hysteresis material, still incredibly confused
about most of the physics which govern the analysis
- spoke with Ian about his orbit modeling software to get a grasp
of what his work will/has accomplish
- talked about ways to go forward, to better his current model
- need to better the way in which the program obtains data about
earth magnetic field intensity and atmospheric density
15.06.2010
(T)
- found a NASA site that will compute/find the magnetic field
intensity, etc for any cordinate and LEO altitude
- obtained MatLab codes that actually do the CUBESIM analysis (for
hysteresis material)
- attempted to decipher how exactly these programs work/where the
calculated data came from
- did not get anything solid done per say, but now have a better
grasp of the way in which the hysteresis rods work & just how big
of a task this project will be
- spoke with Ian again about methods of tracking/mapping orbits
& found that much of the code he needed to write has actually
alread been written in some way or form
- will greatly reduce some of the burden, but this code will need
to be adapted to assemble the completed product
16.06.2010
(W)
- moved away from hysteresis rods [too much!!]
- will now focus on the separation mechanism
- began the creation of an excel sheet that will calculate the
necessary spring constant value for a compression spring that will give
the proper expected separation speed
- found the force necessary to create this separation speed
- will be very small force!
17.06.2010
(R)
- looked into McMASTER-CARR spring plungers (SP)
- NOT defined by k
value as initially calculated
- instead given a max deflection distance and inital/final end
force
- Initial end force: force required to begin to depress the
plunger (implies the spring is slighted compressed to begin with)
- Final end force: force required to depress plunger all the
way, maximum deflection
- given these parameters I computed the spring potential US=1/2*k*x^2
and using an energy balance (assuming all the sprng potential is
converted to kinetic energy) a separation speed is calculated
v=sqrt(k*x^2/m)
- these velocities are compared to the
acceptable range of separation speeds [0.7<v<1.4 cm/s]
18.06.2010
(F)
- checked all calculations for the McMASTER-CARR SP
- attempted to correlate the preliminary spring calculations to a
custom SP...will require some more thought
- will need to use the spring constant provided by the
manufacturer to calculate an expected separation speed
- began the analysis for the leaf-spring alternative
- k value will be found in a
different fashion in accordance to k=1/4*E*b*(t/L)^3
- we will be able to alter the width and length (thickness is
specified by the manufacturer)
- inital thought was to put small leaf-spring boxes with-in the
foot assembly
- this will not work because the L value is way too small and
results in k value upwards of
500 N/m (WAY TOO HIGH)
- Will need to rethink the placement of the leaf-spring mechanism
- need to finish-off a piece of hard plastic for testing in the
vacuum chamber, will be put in a plastic sleeve then all air will be
evacuated
- take 1.5 inches off the length
- square it up
- bevel all edges
WEEK 4
21.06.2010
(M)
- continued analytical analysis for leaf-spring alternative
- because the k values
were too high for placement within the foot the leaf spring will need
to placed elsewhere
- will use a longer leaf (increaseing L, will decrease k)
- place between two feet on opposite sides of the craft
- this new leaf-spring alternative was analyzed and some acceptable
separation speed came out
- used the same matrix: nominal thickness (from McMASTER) vs.
width for varing deflection distances (1-6 mm)
22.06.2010 (T)
- new separation method devised: Tension String
- works basically like a bow and arrow OR a guitar string
- tension the string to a specific frequecy (NEED TUNING KEY)
then deflect the spring with some compression force (due to the two
crafts being loaded into the P-pod) and once this force is removed the
string will move back to the undeflected location causing separation
- did some research to obtain force due to displacement of a taught
string (most of the information from guitar string manufacturers
- string tension: T=4*µ*(L*f)^2
- deflection force: F=4*x*T/L=16*µ*x*L*f^2
- looked into CREEP due to the extreme temperature of the space
environment (failure of material due to various factors, including:
time, temperature, exposure, etc.)
- found that failure due to creep is negligble at approximately
30% of materials boiling point ( approx. 40/50% for ceramics)
- created a table of expected separation speeds for: frequency
(tension) vs. wire thickness (µ) for varied deflection distances
(1-6 mm)
- FB team meeting
23.06.2010 (W)
- cleaned up all excel spread-sheets created thus far
- clearly displayed results at the top of each page
- clearly labeled section titles
- be sure all data is in clear view
- described analytical testing proceedures (all of the calculations
in the spread-sheets) in the TestPlan.doc
- Still need to do conical springs and [custom spring plungers]
<--TJ on this
- informal meeting with Eshon
- discussed the work I've done thus far and talked about the
current possiblites along with some new ideas?
- magnets embedded within the foot assembly; like poles facing
each other in each craft, this will cause a repulsion force (NEED TO DO
SOME ANALYSIS)
- meeting to discuss separation testing proceedures and
prelimiary analysis for next week Wed/Thurs?
24.06.2010 (R)
- began the creation of a spread-sheet to analyze the conical
springs
- obtained part info from the manufacturer (Century Spring Corp)
for tapered springs
- calculated the expected separation speed (using the energy
balance again) for all the tapered springs Century had listed
- the separation speed was calculated using the maximum
deflection and fractions of deflection so to get a better idea of
speeds at varied deflection distances
- all speeds were conditionally formatted, as described below,
and only those springs with yellow/green formatting for half/full were
considered acceptable options to test; came up with only 3 options
- YELLOW: v<0.7 cm/s
- GREEN: 0.7<v<1.4 cm/s
- RED: v>1.4 cm/s
25.06.2010 (F)
- created a results table for both the tension string and the
leaf-spring alternatives (very time consuming); matrix definitions
below [result]
- Leaf-spring: deflection distance vs. width [thickness range]
- Tension String: deflection distance vs. wire thickness
[frequency range]
- devised experiment to determine repulsion force between two
dipoles (permanent magnents)
- a tube slightly larger than the magnets
- drop magnets in so like poles are facing N-N (S-S)
- stack weights on top of the levitating magnet, and the weight
required will be the repulsion force
WEEK 5
28.06.2010
(M)
- thermal analysis meeting
- I've done the most so far with this (preliminary analysis
completed)
- no one else has done anything else (my primary goal now is
the separation mechanisms, will actually be able to complete/see
results by the end of the summer)
- straightend out some terminology issues
- need to be concerned with components that draw/generate 1+
watts, these will require a heat sink
- battery and solar cells most critical components
- spoke of methology to move forward to more in depth analysis
- did more tension string analysis
- idea: with 4 strings on each side (between all sets of feet)=
if 3 fail, left with only 1, and this will produce minimum separation
speed (0.7 cm/s); if none fail, with all 4, will produce the maximum
separation speed (1.4 cm/s)
- did the analysis to obtain the specific tension of the strings
to produce this
- attempted to display these findings on the excel sheet
29.06.2010 (T)
- spent some time developing a tension key design for the tension
string alternative
- going to be modeled after a guitar tuner
- needs to be very small to fit within the foot assembly (7 x 7 x
6 mm)
- contacted a gear manufacturer (Carnes-Miller Gears) about a worm
gear assembly that would fit our specs
- recommended me to his competitors! just because the size of the
assembly was very small for their manufacturing processes
- FB meeting
- need to prepare a presentation (slide-show) to give on Thursday
about the separation strategy test plan
- began preparing the slide-show
30.06.2010 (W)
- worked all day on the presentation; completed the slide-show for
the most part still nees to be proof-read by TJ
- described all alternatives
- tesing proceedures
- highlighted action/discussiong items
1.07.2010 (R)
- touched up the slide-show added some finishing touches
- reviewed/edited all separation documents
- printed final copied of all documents and the slideshow for the
presentation
- gave the presentation, went very well
- all involved very impressed with the presentation
- told to pursue the McMASTER SP and the custom SP; basically put
all of the other options on the back-burner for the time being
- will test these to see if they will give the results we're
looking for; if none of these are acceptable then we will have to
consider some of the other alternatives
2.07.2010 (F)
- not too much today, everyone else has the day off
- got part numbers together and organized (prices, quantities, etc.)
- waited for team meeting said to be at 2PM, but apparently because
of World Cup got delayed to 3PM
- pretty useless for the ME's just told to keep going with the
separation mechanism testing