DIEHARD Data Analysis Final Draft.doc...DIEHARD Colorado Space Grant Consortium University of Colorado at Boulder Page 3 of 26 December 5, 2008 DIEHARD Data Analysis 1.0 Mission Overview

DIEHARD Data Analysis

Demonstrating Intensity of Electromagnetic High Altitude Radiation Determination

Team HASP

Taylor Boe

Kevin Dinkel

Amanda Covington

Melanie Dubin

Space Grant Student Research Coordinator

Brian Sanders

December 9, 2008

DIEHARD

Colorado Space Grant Consortium

University of Colorado at Boulder

Page 2 of 26 December 5, 2008


The organization of the topics below covers the three main components of the DIEHARD

project. This consists of the main science mission implemented by the photometers, the

secondary mission of imaging stars, and the third mission, the overall engineering of the payload.

Each of these areas will be described in detail and include an analysis of functionality and the

conclusions that have surfaced as a result of the data trends.

Table of Contents

1.0 Mission Overview ............................................................................................................................................3

1.1 Flight Overview ...........................................................................................................................................3

1.2 Design Solution Overview ...........................................................................................................................3

1.3 Conclusion ...................................................................................................................................................3

2.0 Photometers ......................................................................................................................................................4

2.1 Standard Tube Photometer ...........................................................................................................................4

2.2 Filter Wheel..................................................................................................................................................5

2.3 Calibration....................................................................................................................................................5

2.4 Analysis........................................................................................................................................................6

2.4.1 Change in Voltage ...............................................................................................................................6

2.4.2 Time to Integrate .................................................................................................................................7

2.4.3 Light Intensity .....................................................................................................................................9

2.4.4 Photometer Spectrum ........................................................................................................................12

3.0 Imaging...........................................................................................................................................................14

3.1 Telescope CCD ..........................................................................................................................................14

3.2 Wide Angle CCD .......................................................................................................................................16

4.0 Payload Engineering.......................................................................................................................................17

4.1 Temperature and Thermal Design............................................................................................................118

4.1.1 Computer .........................................................................................................................................118

4.1.2 Outside ............................................................................................................................................119

4.1.3 Electronics Board ............................................................................................................................119

4.1.4 Science Instruments...........................................................................................................................20

4.1.5 Stepper Motors ..................................................................................................................................20

4.1.6 Disconnected Sensors........................................................................................................................21

4.2 Platform Stability and Accelerometer ........................................................................................................22

4.3 Pressure ......................................................................................................................................................23

4.4 Compass .....................................................................................................................................................24

5.0 Conclusion......................................................................................................................................................25

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1.0 Mission Overview

The University of Colorado at Boulder student team will determine the viability of high

altitude observatories by diurnal imaging of celestial bodies, measuring and recording light

intensity in the stratosphere as a function of altitude, and by nocturnal imaging of celestial

bodies to determine atmospheric turbulence and light intensity due to residuals in the

atmosphere. The DIEHARD payload data will establish whether high altitude platforms are

capable of capturing high quality images of celestial bodies at a lower cost compared to

launching a space telescope like Hubble or constructing a ground based observatory.

1.1 Flight Overview

The DIEHARD payload was launched from Fort Sumner, New Mexico, on September

15, 2008. The approximate launch time was 7:20 AM and the first data package retrieved

from the payload was timed at 7:46 AM. During the daytime, the payload experienced

thermal problems as the computer repeatedly overheated and needed to be manually powered

off. This limited the amount of data points received during the daytime. Once the sun set, the

computer experienced no further thermal problems. The HASP platform ascended to

approximately 36 kilometers and hovered for 32 hours. The CCD camera returned excellent

results throughout the night, capturing stars with both the telescope and wide angle views.

The photometer returned interesting data during the night; however, with the computer

failure throughout the day, a limited amount of data was retained. All platform sensors

returned quality data with the exception of the digital compass, which experienced

interference from all of the electronics onboard.

1.2 Design Solution Overview

Of the problems that the DIEHARD payload faced, all of them can be fixed to enhance

the findings in future experiments. The compass is a vital part of determining the orientation

of the platform. Having a fully functional compass that can record directional orientation of

the payload will be a valuable addition. This shall allow for more accurate identification of

the stars captured on video. Another area for improvement includes the resolution of the

CCD cameras. Having higher quality video shall enhance the amount of stars visible in the

viewing field.

The computer posed a large problem throughout the daytime as it continually overheated.

This shall be fixed by providing a much larger heat sink for the computer electronics to pour

heat into. Because of the reoccurring manual shut down of the computer, there was not

enough photometer data points recorded throughout the first half of the flight. By correcting

the thermal problems with the computer, this inherited photometer malfunction shall also be

corrected.

1.3 Conclusion

The graphs displaying the data are plotted against the hours of flight. Each plot starts at

approximately 7 hours. Each hour of flight after launch is the next consecutive value up to

hour 31. The sun set at approximately hour 20 and rose again at 30 hours. From the data that

the DIEHARD payload retrieved, much progress has been made toward proving the

feasibility of high altitude observatories. The stability of the platform and the physical

capability of capturing images of celestial bodies through relatively low quality CCD

cameras help to provide valuable evidence. The photometers provided interesting data

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regarding the sky brightness in the upper atmosphere throughout the flight. This document

shall bring the possibility of high altitude observatories one step closer to becoming a

realistic future mission.

2.0 Photometers

Photometers were used to record light intensity readings throughout the flight. Quality

data trends of ambient light intensity shall determine the feasibility of seeing stars at different

altitudes and positions. Each of the three photometers, oriented at different positions as

shown in figure 2.0a and 2.0b, return quality data trends that will help determine the altitude

at which quality imaging can be maximized. It is evident from analysis that each photometer

had its own unique behaviors. This must be taken into account when reviewing the

photometer data.

2.1 Standard Tube Photometer

The standard photometers, figure 2.1, successfully recorded light intensity throughout the

flight. Sky brightness readings are calculated by measuring the time necessary to fill up each

capacitor and its corresponding final voltage from a photodiode. The equation used to

determine sky brightness in watts per square meter is L=(4/π)(n2/a

2)(C/K)(∆V/∆t) as cited

from Yorke J. Brown, PhD. This

equation gives the value of light

intensity in watts/m2-sr of the

“glowing” patch of sky observed

by each photometer. Each

photometer was built with a 10½

inch baffling tube so that the

light striking each photodiode is

essentially parallel.

Figure 2.0b: This figure represents the relative angles of the

scientific instruments mounted onboard.

Figure 2.1: This photograph shows the orientation of the photometers mounted in the payload

Figure 2.0a: The science instruments in the payload take data

from two sides of the box.

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Figure 2.3: This photograph shows the three photometer

circuits mounted inside the payload.

For the first half of the flight when the sun was high in the sky, the photometers took only

seconds to completely integrate, and the change in voltage reaches the maximum of 10V.

Once the sun has set, the integration time exceeds 200 seconds due to a dramatic decrease in

light intensity.

2.2 Filter Wheel

Photometer #1 incorporated a filter wheel, figure 2.2, which allowed the photometer to

focus on a single spectrum of light at a time. A motor made it possible to switch the filter

after each consecutive light reading. The data from this particular sensor shall provide

answers to determine the spectrum of light that is most prevalent from distant celestial

bodies.

The filters included:

0-No Filter: all wavelengths

1-Green (visible): 495–570 nm

2-Red (visible): 620-750 nm

3-Infrared: 750-1000 nm

During the flight, an error was received about the functioning of the filter wheel. It is

highly possible that the wheel may not have been changing filters during flight. From the

data found in the sections below it is evident that there is no real difference between the light

captured by the different filters. This suggests that the wheel may have indeed not been

turning during flight. Thus, only one filter may have been read. However, in the section

below, the readings are split up by filter.

2.3 Calibration

One challenge that the DIEHARD team faced was the calibration of the three

photometers onboard the payload. Hundreds of hours went into reconfiguring the circuits to

transfer the light readings from each photometer to the computer in the form of numerical

data. In future missions, this particular challenge shall be improved.

It is evident that errors were made in replacing capacitors, as photometers #2 and #1

integrated 10 times faster than photometer #3. Photometer #2 and #1 were found with 100 pF

capacitors, instead of the preferred 1000 pF capacitor. We compensated for this error in our

photometer analysis.

Also, each photometer board, figure

2.3, though built with the exact same

materials and in the exact same manner,

each returned completely unique data,

both in tests and during the flight. Each

photometer must be analyzed relative to

itself and not to other photometers, as they

behave so differently. This makes data

Figure 2.2: This photograph shows the filter wheel photometer. The

wheel cycled through the filters powered by a stepper motor.

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analysis immensely difficult, and the validity of the data is brought into question. This is an

error that must be improved upon for future flights.

2.4 Analysis

Judging by the trends shown in the figures below, the photometers appear to have returned

relatively accurate data with respect to the time in flight and the known position of the sun

and moon.

2.4.1 Change in Voltage

Figure 2.4.1a shows the voltage change in all three photometers. As can be seen, they all

behaved quite differently. Photometer #3 seemed to charge up to its full capacity (almost

10V) throughout the entire flight. This seems also true for photometer #2 until night time.

This is very interesting because both photometers should have been looking at the same night

sky. The broadband filter on photometer #1 seemed to charge halfway during the night,

setting an average between the other two photometers.

It is is evident that photometer #2 may

have been looking at the balloon for the

entire flight, especially at higher altitudes

where the balloon grows to an enormous

size. Using trigonometry, figure 2.4.1b, this

hypothesis seems probable. Estimating that

the radius of the balloon is 600ft and the

flight string is 600ft below the bottom of

the balloon leaves an angle of sight that

must be less than 63.74 degrees.

Photometer #2 was mounted at

Figure 2.4.1a: This graph shows the voltage change in all three photometers throughout the duration of the flight.

Figure 2.4.1b: This diagram represents the possibility of the balloon obstructing

the view of photometer #2.

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approximately 64.79 degrees above the horizon. Perhaps the fully inflated balloon prohibited

it from seeing the small amounts of light from stars.

2.4.2 Time to Integrate

Figure 2.4.2a shows the time it took for the photometers to integrate. Once again it is

visible that photometer #2 was not taking in much light during the night, as it maxed out at

300 seconds before reset every time. This is also true for the broadband filter on photometer

#1. In this graph there is an interesting artifact found around 24 hours and 27.5 hours for

photometer #1, 26 hours for photometer #2, and 25 hours for photometer #3. These

downward spikes look very similar; however, they occur at different time intervals.

It seems to be a valid

hypothesis that the

photometers may be

picking up reflected light

from the moon. Again,

the reason for this may

have much to do with the

different angles at which

the photometers were

mounted, figure 2.4.2b.

In the videos, the moon is

seen mostly on the right

edge of the screen at

approximately the hour

29 of the flight. As the

moon rose in the night

sky, its light was first

picked up by photometer

#1, and later by

photometer #3, both of

which are at lower angles, as shown in the figure above. Later, the moon’s intense light was

discovered by the steep angle of photometer #2. As the moon began to set, photometer #1

was fortunate enough to catch its light again. Finally, around the 29th

hour the wide angle

CCD camera, set at 25.84

degrees, captured the moon

as it set.

Figure 2.4.2c shows a

zoomed in view of the

integration time during the

day. It is evident that each

of DIEHARD’s three

photometers had very

different integration rates.

The capacitors used on

photometer #1 and #2

integrated ten times faster

Figure 2.4.2b: This diagram shows the orientation of the moon throughout the flight at the approximate

times to which the data correlates.

Figure 2.4.2a: This graph shows the time to integrate for all three photometers

throughout the flight. Notice the interesting spikes during the night.

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than the capacitor on

photometer #3. Photometer

#3 used a 1000 pF capacitor,

while the other two used 100

pF capacitors. The use of

different capacitors was a

fundamental engineering

flaw in the science

component of the DIEHARD

platform. However, this

difference was accounted for

in analyzing the light intensity

readings of the photometers.

Figure 2.4.2c: This graph shows the integration time for all three photometers during the day.

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2.4.3 Sky Brightness

Photometer #1:

This photometer utilized

a filter wheel during flight.

The graphs on the left show

only the readings from the

broadband spectrum. The

brightness readings

throughout the flight seem

very plausible. During the

day, sky brightness varied

mostly between .007 and .01

watts/m2-sr. There seems to

be more fluctuations from

hour 15 to hour 20. During

this time the sun is at a lower

angle in the sky, nearing the

angle at which photometer #1

is mounted, 55.23 degrees.

Direct sunlight most likely

entered the baffling tube

during this time, causing the

relevant spikes in the data.

During the night, the sky

brightness is much lower,

barely surpassing a zero

value. However, there is

unmistakably some light that

enters the photometer tube.

The spikes occurring at night

could be a function of the

light from the moon, as

discussed above.

Entire Flight

Day Time

Night Time

Figure 2.4.3a: These graphs show the relative sky brightness of photometer #1 throughout the flight.

They have been separated into night time and day time to better display the minor fluctuations

throughout the night.

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Photometer #2:

Photometer #2 had the

steepest angle of all the

photometers. This may

explain why during the

middle of the day, when the

sun is overhead, the sky

brightness is consistantly

higher than the other

photometers. Its average

range is between .05 and .12

watts/m2-sr from hour 10 to

15 and drops steadily after

hour 15.

During the night,

Photometer #2 barely took in

any light, as the readings are

essentially zero. There was

one very small spike around

26 hours, however, even that

spike is only about 7.0E-4

watts/m2- sr.

Entire Flight

Day Time

Night Time

Figure 2.4.3b: These graphs show the relative sky brightness of photometer #2 throughout the flight.



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Photometer #3:

Photometer #3

fluctuated from .0025 to

.012 watts/m2-sr during the

day, which was relatively

darker than photometer #2,

possibly due to its lower

angle. There is a

considerable amount of

fluctuation from hour 16 to

19. This could be caused by

the sun which, like with

photometer #1, may send

light directly into the tube

as it approaches the low

angle of 54.05 degrees in

the sky. Direct sunlight

would have caused the

drastic spikes in this time

range.

During the night, not

much light entered into the

photometer. However, the

light that does charge the

diode is considerably more

intense than the light which

entered photometer #2.

Entire Flight

Day Time

Night Time

Figure 2.4.3c: These graphs show the relative sky brightness of photometer #3 throughout the flight.



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2.4.4 Photometer

Spectrum

Integration Time:

The integration time for

the filter wheel followed the

same basic trend as the other

photometers. By zooming in

on the data from just the

daytime it is evident that

different filters had no real

affect on the time it took for

the photometers to integrate.

During the night there is also

no real difference. All of the

different filters took the

maximum time of 300

seconds to fill up for the

entire night, with the

exception of the downward

spikes.

Change in Voltage:

During the day, all of the

frequencies completely charged to 10V,

figure 1.1.4.4. During the night there

seems to be minimal fluctuation. The

green filter seems to produce the most

voltage, followed by infrared,

broadband, and red. However, this data

trend is not extremely reliable due to

the minimal amount of data points for

each filter.

Entire Flight

Day Time

Figure 2.4.4a: These graphs show the integration time for the filter wheel photometer

for the entire flight and zoomed in to see the fluctuation during the day.

Figure 2.4.4b: This graph shows the change in voltage for the filter wheel

photometer for the entire flight.

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Sky Brightness:

During the day the sky

brightness readings for each

filter produced very similar

values, averaging around .01

watts/m2-sr with the

exception of the spikes,

which could possibly be due

to the setting sun.

During the night, all the

filters were relatively dark,

falling between a range of

1.2E-5 to 2.2E-5 watts/m2-

sr. The differences in the

values are so minimal that it

is hard to distinguish if the

filter makes that much of a

difference.

From the gathered data, it

is evident that for the most

part, all visual frequencies

seem to be equally prominent

during both day and night in

the upper atmosphere. During

testing, we discovered that

infrared seemed to integrate

at a small fraction of a

second slower than the rest of

the tested spectrum, but

during flight, the infrared did

not differ very drastically at

all from the other filters. It

seems that with our

instrumentation we could not

decipher any real difference

in the sky brightness of

different frequencies in the

upper atmosphere.

Entire Flight

Night Time

Figure 2.4.4c: These graphs show the relative sky brightness of the filter wheel photometer

throughout the entire flight and zoomed in during the night to display the small

fluctuations in brightness.

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3.0 Imaging

Imaging of stars from a high altitude platform can be successful, as shown in the

telescope video and wide angle CCD recordings. The hard evidence displayed by the cameras

provides undisputable support for additional research concerning imaging stars from lighter-

than-air platforms. Nevertheless, there is vast room for improvement from the standpoint of

image quality. As well as capturing physical images of stars, the CCD camera on the payload

also helps to determine the stability and orientation of the platform while in flight.

3.1 Telescope CCD

The telescope video portrays an interesting

point of view. Being much more “zoomed in”

than the wide angle CCD (field of view near one

degree, figure 3.1a), the smallest movements in

the platform are evident in the movement of the

stars. After closely observing the videos, it

became clear that the platform does occasionally

oscillate, noted by stars that move across the

screen with slight up and down movements.

Through analyzing the pitch of the platform in a

one percent field of view, there is distinct

movement; however, it is less than 5 percent of

the one degree viewable field, indicating that

the pitch of the platform oscillates in a very

minimal range. This analysis reveals that the

platform maintains relative stability in the vertical axis. A change in rate at which the

platform rotates is also very clear, indicating that there may be slight winds in the

environment that speed up and slow down

the movement of the platform

(HASPFLIGHTcam2.16-09-08.05_17_47).

The types of movements detected are

hypothetically caused by the movements of

the balloon above. With its enormous

surface area, movement will be influenced

by a small magnitude of air current.

Physically, the video captured with the

telescope shows stars, but being only a one

degree field of view, they pass through the

shot quickly and begin to lose focus

moving through the left quarter of the

screen. The unknown focusing error was

not an issue for analyzing the data, which

will be explained later. The rate of the stars’

apparent movement changes throughout the

flight, but on average a star does not stay in view for more than five seconds and sometimes

less than a second. Taking still screen shots does not do justice to what was actually captured

on video. The telescope recorded visible stars as the sun went down

Figure 3.1a: This diagram represents the difference between the

field of view of the telescope CCD video versus the wide angle

CCD video

HASPFLIGHTcam2.15-09-08.19_02_28

Figure 3.1b: This screenshot from the telescope CCD video

shows the first visible star during the flight which was captured

around 7:02 PM.

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(HASPFLIGHTcam2.15-09-08.19_02_28) and also may have captured recognizable

constellations like Orion (HASPFLIGHTcam2.16-09-08.00_33_50). Overall, the telescope

more effectively portrayed the behavior of the platform on video rather than recording

quality images of celestial bodies. However, valuable information from DIEHARD shall help

achieve further success on future missions.

08.00_33_50


Figure 3.1c: This screenshot from the telescope CCD video

shows a group of stars that may be the constellation Orion.

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3.2 Wide Angle CCD

The video from the CCD camera

portrays the relative stability as the

platform slowly spins. Stars do not

become visible until

HASPFLIGHTcam1.15-09-

08.19_36_41, which is approximately

11 hours into the flight. This particular

video shows great potential for the

ability to image celestial bodies from a

high altitude platform. Due to the fact

that the sun is still above the horizon,

the video is gray, indicating remnant

light in the environment, and stars are

still visible using a low quality CCD

camera. Under these conditions and

using a high quality imaging device,

spectacular images could plausibly be

captured, essentially proving the

overarching mission of DIEHARD

With the wide angle CCD camera

viewing a twenty degree field

(reference figure 3.1a), several videos

were incrementally viewed throughout

the duration of the flight to analyze the

rotational rate in particular. The

platform’s rate of rotation, figure 3.2b,

ramained relatively constant but

seemed to rotate slightly quicker right

after sunset and two hours after. This

occurrence could be due to the flow of

air masses while the sun is still present

as warm and cool air mingle to cause

more movement of the balloon and

consequently the platform. Being that

there were little or no stars to use as

reference during the day, the rotation

could not clearly be determined until

stars were visible. The rotation ranged

from .5 degrees per second down to

.12 degrees per second, a relatively

mild rotation rate.

Figure 3.2a: These screenshots from the wide angle CCD camera show a

group of stars right after sun set as they move across the screen left to right.

Interestingly, there is a stationary bright point which may be a pixel.


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As the mission progressed, star images became

more vibrant, capturing several constellations,

including a clear view of Orion

(HASPFLIGHTcam1.16-09-08.02_03_24). To

further enhance the images taken from DIEHARD,

we will attempt to stack still images from the CCD

video to try and enhance faint stars hiding in the

background. With more vibrant star patterns,

constellations shall be more readily identified to

indicate the orientation of the platform at a given

time. This part of our investigation is still in

progress could lead to determining more visible

constellations. This has not been the focus of our

analysis because we are primarily concerned with

proving that stars can be imaged from a high

altitude observatory, and this has been

accomplished with relatively simple instruments.

4.0 Payload Engineering

Engineering the DIEHARD payload involved creating a design which provided thermal

protection for all components and a solid structure to ensure data recovery post landing. The

payload was fitted with several temperature sensors as well as accelerometers, a compass and

pressure sensor.

Figure 3.2b: This graph shows an average rate of rotation of the platform throughout the flight derived from the wide angle videos.

Figure 3.2c: This screenshot shows an excellent view of the Orion constellation

from the wide angle CCD camera

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4.1 Temperature and Thermal Design

The following sections show the thermal status of our payload for the duration of the flight.

The DIEHARD payload had 12 temperature sensors; however, only 10 were functioning

during flight. Two of them were disconnected or removed prior to launch. Figure 4.1 shows

the location of the temperature sensors inside the payload.

4.1.1 Computer

The temperature readings internally

and externally gave insight into the

thermal attitude the DIEHARD payload.

As the computer continually approached

the point of overheating itself, it was

manually shutdown. The computer was

turned back on once it cooled to 38

degrees Celsius. This is demonstrated by

the abrupt diagonal lines in figure 1.3.1a.

As the flight progressed, the computer

cooled down at a faster rate, which is

indicated by the steeper diagonal slope.

This is most likely caused by the colder

outside temperatures. In future missions,

this problem can be solved by providing a

larger conduction surface for the

computer to expel its heat.

Figure 4.1.1: This graph shows the temperature recorded by the sensor attached to the

computer. Notice the negative sloping linear sections. These represent the times when

the computer was shut down.

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4.1.2 Outside

The outside temperature profile,

represented in figure 1.3.1b, demonstrates

the greatest fluctuation of any of the

payload’s temperature sensors. It has a

minimum of -50 degrees Celsius, which is

a result of the extremely cold nights in

near space, and a maximum of 70 degrees

Celsius, which may be due to the extreme

heat from the sun during the day or the

conduction of the heat from inside the

payload. The coldest time of the flight

occurred after the sun set, which was at

about 20 hours. The graph’s rapid spikes

during the daytime could be caused by the

rotation of the platform. When the outside

temperature board is pointed directly at the sun in the upper atmosphere, the temperature

spikes upwards very fast. Likewise, the platform also cools very fast when it is pointed away

from the sun.

4.1.3 Electronics Board

The electronics board temperature profiles

are shown in figure 1.3.1c. The power board

temperature seemed to fluctuate more than

any of the other electronic boards. This is

interesting, as it oscillated at 10 degrees

amplitude regularly over the course of just a

few minutes.

Figure 4.1.2: This graph shows the temperature recorded by the sensor

attached to an exterior outside wall of the payload. The linear sections

represent the times when the computer was shut down.

Figure 4.1.3: This graph shows the temperature recorded by the sensor s

attached to the large interior circuit boards. These recorded relatively

warm temperatures throughout the flight due to the heat created by the

electronics.

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4.1.4 Science Instruments

The science instrument temperature

sensors, figure 1.3.1d, were mounted on the

CCD wide angle camera and photometers

#2 and #3. The three science instruments

were spread evenly throughout the payload,

covering three of the four corners. This

graph demonstrates that the internal

temperature seemed to be fairly evenly

distributed throughout the payload for the

duration of the flight.

4.1.5 Stepper Motors

The stepper sensor’s temperature profile is shown in

figure 1.3.1e. The sun shade, though outside, is seen at

relatively high temperatures for the duration of the

flight. This is most likely a result of the sensor being

attached to a hot running motor. The filter wheel,

located inside the payload, got colder at a slower rate

than the sun shade, which was exposed to the outside

elements.

Figure 4.1.4: This graph shows the temperature recorded by the sensor s

attached to the science instruments. This data shows the most accurate

internal temperatures throughout the flight.

Figure 4.1.5a: This photograph shows the location of the external

temperature sensor which was mounted on the stepper motor controlling

the sun shade. There was a second temperature sensor located internally

on the stepper motor controlling the filter wheel.

Figure 4.1.5b: This graph shows the temperature recorded by the sensor s

attached to the internal and external stepper motors (reference figure

4.1.6b).

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4.1.6 Disconnected Sensors

Although these temperature sensors,

figure 1.3.1f, were disconnected or removed

for the flight, they still produced data

readings. This is due to the fact that the wires,

although disconnected from the temperature

sensor, were still connected to the

corresponding port on the serial data read-in

to the computer. So, all of the noise created by

the electronics onboard were picked up by the

disconnected wires. This errant data does not

represent any bias toward the data from the

other functioning sensors.

Figure 4.1.6: This graph shows the temperature recorded by the

disconnected sensors. Interestingly, they follow the same general trend as

the rest of the temperature sensors due to the ability of the open serial

wires to conduct the excitement of electrons as temperature changes.

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4.2 Platform Stability and Accelerometer

The accelerometer onboard the

payload, figure 4.2a, was used to

determine the turbulence during

flight. The accelerometer data

corresponds with the video images

which results in an accurate

account of the flight’s stability.

After plotting data from the

accelerometers, an interesting

occurrence arises. Clearly visible in

the accelerometer data, the X axis

shows some intriguing behavior,

figure 4.2b. While the Z axis and Y

axis fluctuate within a ½ G value,

the X data fluctuates up to 3½ G’s.

By plotting the basic temperature

trend of the HASP platform next to

the accelerometer data, figure 4.2c,

an interesting conclusion arises. It

seems plausible that the X axis of

the accelerometer was getting an

error reading due to the drastic

decrease in temperature of the

flight. The errors in the

accelerometer data correspond

directly to the two coldest parts of

flight, launch and during the night.

The accelerometer data was not

of much use in analyzing the

behavior of the platform. It seemed

to stay relatively calm throughout

the duration of the flight. This is

very promising for the prospect of

a high altitude observatory.

Accelerometer

behind heat sink

Figure 4.2a: The accelerometer in the figure above gave data for X, Y,

and Z axis for the duration of the flight.

Figure 4.2b: The accelerometer error is visible in the black x axis.

Figure 4.2c: The error visibly relates to the relative temperature during the

flight.

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4.3 Pressure

The pressure sensor was located

inside the payload on the avionics board,

figure 4.3a. The pressure data, figure

4.3b, shows how the pressure decreases

as the altitude increases. A half hour into

the flight, the pressure decreased to

nearly half of what it is on Earth’s

surface, from 14 pounds per inch2 (PSI),

to 7 PSI. After reaching maximum

altitude, the pressure decreased to 1.5

PSI, which is what we would expect in a

near space environment.

Pressure Sensor

Figure 4.3a: The pressure sensor was hidden behind the heat sink.

Figure 4.3b: The pressure data matches the trend that was expected prior to flight.

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4.4 Compass

The compass was located inside the payload directly above the CCD wide angle camera,

figure 4.4a. It encountered an error during flight due to electromagnetic interference from the

computer and other components onboard the payload, as can be seen by the flat line, figure

4.4b. This is an unfortunate result, as the compass could have helped determine the

orientation of the platform at any given time during the flight. It could have also given

accurate rotational speeds and the precise attitude behavior of the platform. For future

missions, the compass error will have to be corrected in order to provide accurate directional

orientation.

Compass

Figure 4.4a: The compass failed because of its location

relative to the overhanging computer.

Figure 4.4b: The compass failure is denoted by the strait

line obtained from the data.

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5.0 Conclusion

The DIEHARD mission, stationed on the HASP balloon, has made gigantic strides in

proving the feasibility of stationing an optical observatory at the edge of space. The first

question asked of such an observatory would be its ability to capture images of the stars with

precision and quality. The HASP payload was able to capture hundreds stars during the night

and even during sunset with a simple CCD wide angle camera. The telescope CCD also

captured light from more distant stars. The videos also demonstrated accurately the

conditions of the upper atmosphere. From a free hang below a balloon the maximum

rotational velocity was a very mild ½ degree per second. With a simple stabilization system,

a lighter-than-air observatory could easily counteract this disturbance. The photometer data

showed that there is definitely enough light during the night time to be seen visually. Even

the very small patches of night sky detected were enough to provide charge from the

photodiodes. This is very impressive and is promising for the prospect of optical viewing of

the cosmos at high altitudes.

However, some questions still remain. Can stars be observed even during the day time?

With our simple video capturing devices, the sky was an unfortunate gray during the day.

However, with more advanced instruments and image editing capabilities, it is very feasible

that stars could be viewed during the day time. Hopefully the evidence from the DIEHARD

payload is enough to accurately set the course for the mission of HASP Flight 2009, one

which may further prove the practicality and benefits of a balloon-stationed observatory.

These are constructed airship prototypes that may be used to carry a small telescope to high altitudes

in order to take high quality images of celestial bodies.

http://thinker.colorado.edu/space/fall_2007/downloads/airship_spie.pdf

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Acknowledgements:

On behalf of the 2008-2009 HASP team, we would like to give thanks and recognition to

the following individuals:

Dr. Robert Fessen, Dr. Yorke Brown, Dr. Elliot Young, Kyle Kemble, Grant Fritz, Viliam Klein,

Ahna Isaak, Brian Sanders, Chris Koehler and all of those at the Colorado Space Grant

Consortium who have offered guidance.

Documents

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