1
00:00:07,430 --> 00:00:04,710
this is mission control houston again uh

2
00:00:10,230 --> 00:00:07,440
joining us by telephone today we have a

3
00:00:12,629 --> 00:00:10,240
special guest uh interview with uh

4
00:00:15,270 --> 00:00:12,639
debbie judd reedy who is from the

5
00:00:17,830 --> 00:00:15,280
georgia institute of technology and he's

6
00:00:20,310 --> 00:00:17,840
just gotten happy news that his

7
00:00:24,070 --> 00:00:20,320
experiment that is going to be looking

8
00:00:26,150 --> 00:00:24,080
at how to improve uh the manufacture of

9
00:00:28,070 --> 00:00:26,160
photovic voltaic cells on the

10
00:00:29,349 --> 00:00:28,080
international space station

11
00:00:32,310 --> 00:00:29,359
is actually going to fly to the space

12
00:00:34,630 --> 00:00:32,320
station welcome dr reedy thank you kelly

13
00:00:36,709 --> 00:00:34,640
it's uh it is a very exciting it's a

14
00:00:37,990 --> 00:00:36,719
boyhood dream come true to fly in space

15
00:00:40,229 --> 00:00:38,000
even if i'm not actually doing it

16
00:00:42,229 --> 00:00:40,239
something that we handle is is going to

17
00:00:43,750 --> 00:00:42,239
do it so that's it's very exciting well

18
00:00:45,510 --> 00:00:43,760
welcome to mission control tell us a

19
00:00:48,310 --> 00:00:45,520
little bit more about your experiment

20
00:00:50,150 --> 00:00:48,320
well what our experiment does is use a

21
00:00:51,750 --> 00:00:50,160
light trapping morphology on the solar

22
00:00:53,990 --> 00:00:51,760
cell it's a three-dimensional solar cell

23
00:00:56,229 --> 00:00:54,000
so it captures light from multiple

24
00:00:59,349 --> 00:00:56,239
angles which is particularly relevant on

25
00:01:02,389 --> 00:00:59,359
the space station because it goes around

26
00:01:04,469 --> 00:01:02,399
so many times the earth so many times um

27
00:01:07,429 --> 00:01:04,479
you've got mechanical tracking arrays on

28
00:01:10,710 --> 00:01:07,439
it to keep the the solar flux uh

29
00:01:12,149 --> 00:01:10,720
powering the the the channels

30
00:01:16,149 --> 00:01:12,159
and we're looking at some pictures that

31
00:01:18,710 --> 00:01:16,159
you sent us these look like tiny cubes

32
00:01:19,990 --> 00:01:18,720
uh yes we've got um

33
00:01:21,510 --> 00:01:20,000
they're actually

34
00:01:23,670 --> 00:01:21,520
if you zoom right in the carbon

35
00:01:24,870 --> 00:01:23,680
nanotubes are very um

36
00:01:26,310 --> 00:01:24,880
vine like

37
00:01:28,469 --> 00:01:26,320
and so we try to coat those with our

38
00:01:30,230 --> 00:01:28,479
photo absorber materials

39
00:01:31,830 --> 00:01:30,240
we've done it in the past using cadmium

40
00:01:34,390 --> 00:01:31,840
telluride as the

41
00:01:36,550 --> 00:01:34,400
the photon absorbing material

42
00:01:38,870 --> 00:01:36,560
this proposal is using a new chemistry

43
00:01:41,109 --> 00:01:38,880
new photochemistry known as czts copper

44
00:01:41,990 --> 00:01:41,119
zinc 10 sulfide

45
00:01:43,190 --> 00:01:42,000
okay

46
00:01:44,630 --> 00:01:43,200
and so uh

47
00:01:47,030 --> 00:01:44,640
you mentioned that they're three

48
00:01:48,230 --> 00:01:47,040
dimensional i'm guessing that the cells

49
00:01:49,990 --> 00:01:48,240
were using

50
00:01:51,510 --> 00:01:50,000
in most applications here on the ground

51
00:01:53,990 --> 00:01:51,520
and in space right now are two

52
00:01:55,670 --> 00:01:54,000
dimensional type cells that's correct

53
00:01:57,030 --> 00:01:55,680
they're planar there was before we

54
00:01:59,749 --> 00:01:57,040
developed this technology back in the

55
00:02:01,510 --> 00:01:59,759
early 2000s there was no way to texture

56
00:02:03,190 --> 00:02:01,520
what are known as thin film

57
00:02:04,709 --> 00:02:03,200
um

58
00:02:07,190 --> 00:02:04,719
photovoltaic cells you they could

59
00:02:09,669 --> 00:02:07,200
texture silicon cells by etching little

60
00:02:11,510 --> 00:02:09,679
pyramids into the

61
00:02:12,949 --> 00:02:11,520
silicon structure itself

62
00:02:14,790 --> 00:02:12,959
and that would provide a light trapping

63
00:02:17,190 --> 00:02:14,800
basically what it does is it allows the

64
00:02:19,350 --> 00:02:17,200
photon of light to hit the solar cell

65
00:02:21,990 --> 00:02:19,360
and if it does not get absorbed it will

66
00:02:23,990 --> 00:02:22,000
reflect off and hit the solar cell again

67
00:02:25,830 --> 00:02:24,000
inside this pyramidal pit well we do the

68
00:02:27,030 --> 00:02:25,840
same thing but we create vertical

69
00:02:29,110 --> 00:02:27,040
structures

70
00:02:32,070 --> 00:02:29,120
that we then coat with with our photo

71
00:02:34,470 --> 00:02:32,080
absorbers such as cad tell sigs ccts all

72
00:02:36,390 --> 00:02:34,480
the various different thin film

73
00:02:38,869 --> 00:02:36,400
absorbers okay and you mentioned that

74
00:02:41,110 --> 00:02:38,879
this has potential uh applications in

75
00:02:43,430 --> 00:02:41,120
space because naturally you've got a

76
00:02:45,110 --> 00:02:43,440
more three-dimensional capability to

77
00:02:47,430 --> 00:02:45,120
collect the sunlight

78
00:02:49,350 --> 00:02:47,440
uh in space as the space station orbits

79
00:02:50,390 --> 00:02:49,360
the earth and the solar rays can track

80
00:02:52,630 --> 00:02:50,400
the sun

81
00:02:54,070 --> 00:02:52,640
what about on earth is this technology

82
00:02:56,710 --> 00:02:54,080
of potential use for us here on the

83
00:02:59,270 --> 00:02:56,720
ground certainly it'd be very useful on

84
00:03:01,830 --> 00:02:59,280
the ground the key benefit from the czts

85
00:03:04,070 --> 00:03:01,840
absorber is it's low low cost

86
00:03:06,550 --> 00:03:04,080
the 3d

87
00:03:08,390 --> 00:03:06,560
morphology allows us to capture light

88
00:03:10,470 --> 00:03:08,400
without having tracking arrays usually

89
00:03:13,350 --> 00:03:10,480
we don't have tracking arrays on a

90
00:03:14,869 --> 00:03:13,360
terrestrial emplacement of a solar cell

91
00:03:17,350 --> 00:03:14,879
usually you just sort of optimize that

92
00:03:19,509 --> 00:03:17,360
on the roof at a given angle that's

93
00:03:21,430 --> 00:03:19,519
as close as perfect as you can get which

94
00:03:23,110 --> 00:03:21,440
is not very close at all

95
00:03:24,390 --> 00:03:23,120
for your latitude and

96
00:03:27,910 --> 00:03:24,400
and where you are on the face of the

97
00:03:29,270 --> 00:03:27,920
earth with the 3d solar cell

98
00:03:31,589 --> 00:03:29,280
well excuse me with the planar solar

99
00:03:33,270 --> 00:03:31,599
cell they perform best at high noon

100
00:03:35,509 --> 00:03:33,280
where the incident flux is as

101
00:03:37,910 --> 00:03:35,519
perpendicular to the cell as possible

102
00:03:40,550 --> 00:03:37,920
with ours actually we want to be off

103
00:03:42,550 --> 00:03:40,560
angle slightly to allow for more photon

104
00:03:43,910 --> 00:03:42,560
impingements on within the the various

105
00:03:45,509 --> 00:03:43,920
different towers that

106
00:03:48,789 --> 00:03:45,519
were shown earlier with the various

107
00:03:51,030 --> 00:03:48,799
slides okay would this allow you to to

108
00:03:53,910 --> 00:03:51,040
get collect more electricity with a

109
00:03:56,630 --> 00:03:53,920
smaller cell set of cells yes it's

110
00:03:58,309 --> 00:03:56,640
really about the integrated energy from

111
00:04:00,070 --> 00:03:58,319
sunrise to sunset that we're able to

112
00:04:03,030 --> 00:04:00,080
capture because ours will go up whereas

113
00:04:05,670 --> 00:04:03,040
the planar cell will always go down

114
00:04:08,390 --> 00:04:05,680
so that across the entire

115
00:04:10,390 --> 00:04:08,400
span of the sun rising to sun setting we

116
00:04:12,309 --> 00:04:10,400
absorb more more photons due to the

117
00:04:14,229 --> 00:04:12,319
light trapping we're also able to

118
00:04:17,349 --> 00:04:14,239
extract them better because our thin

119
00:04:19,830 --> 00:04:17,359
film absorber is significantly thinner

120
00:04:21,509 --> 00:04:19,840
because we're assured of the absorption

121
00:04:23,670 --> 00:04:21,519
so the carrier pathway getting the

122
00:04:25,749 --> 00:04:23,680
electrons out of the structure to create

123
00:04:27,110 --> 00:04:25,759
useful electricity

124
00:04:29,270 --> 00:04:27,120
is much shorter so there's a higher

125
00:04:31,270 --> 00:04:29,280
probability that they'll come out

126
00:04:33,270 --> 00:04:31,280
all right and uh have you heard any

127
00:04:34,469 --> 00:04:33,280
indications yet on when your experiment

128
00:04:37,430 --> 00:04:34,479
is going to fly

129
00:04:39,990 --> 00:04:37,440
um it's a 12-month program so it'll

130
00:04:43,110 --> 00:04:40,000
start in terms of making these things so

131
00:04:45,590 --> 00:04:43,120
that'll start i guess probably may 1st

132
00:04:47,749 --> 00:04:45,600
middle of april perhaps if we're lucky

133
00:04:49,030 --> 00:04:47,759
and then once we deliver it after 12

134
00:04:50,790 --> 00:04:49,040
months

135
00:04:52,310 --> 00:04:50,800
there'll be the integration that cases

136
00:04:53,670 --> 00:04:52,320
will perform

137
00:04:55,189 --> 00:04:53,680
i believe it's going up on a dragon

138
00:04:56,469 --> 00:04:55,199
vehicle that you've been showing it's a

139
00:04:59,189 --> 00:04:56,479
beautiful vehicle so i look forward to

140
00:05:00,629 --> 00:04:59,199
riding on that and um

141
00:05:02,390 --> 00:05:00,639
i have no idea how long it will take

142
00:05:04,150 --> 00:05:02,400
from when i get it in cases of hands to

143
00:05:05,590 --> 00:05:04,160
uh go to launch but i guarantee you'll

144
00:05:07,110 --> 00:05:05,600
be at the launch site watching it and

145
00:05:09,510 --> 00:05:07,120
cheering for it

146
00:05:11,590 --> 00:05:09,520
okay uh you know you mentioned that this

147
00:05:13,029 --> 00:05:11,600
was kind of a dream come true tell us a

148
00:05:14,550 --> 00:05:13,039
little bit about yourself where where

149
00:05:16,390 --> 00:05:14,560
did where were you born where'd you grow

150
00:05:18,230 --> 00:05:16,400
up and how did you get into space

151
00:05:20,710 --> 00:05:18,240
research um

152
00:05:22,629 --> 00:05:20,720
i am born in north carolina

153
00:05:25,670 --> 00:05:22,639
winston-salem but grew up in chapel hill

154
00:05:27,270 --> 00:05:25,680
um so go tar heels

155
00:05:28,550 --> 00:05:27,280
we've got

156
00:05:30,070 --> 00:05:28,560
space has always been a boyhood dream

157
00:05:32,629 --> 00:05:30,080
i've applied for the astronaut program

158
00:05:34,150 --> 00:05:32,639
since 99

159
00:05:35,350 --> 00:05:34,160
but

160
00:05:36,550 --> 00:05:35,360
it was beginning to look like i'm

161
00:05:37,749 --> 00:05:36,560
probably not going to be able to fly in

162
00:05:38,469 --> 00:05:37,759
space myself

163
00:05:41,909 --> 00:05:38,479
so

164
00:05:43,990 --> 00:05:41,919
research up there that's a pretty good

165
00:05:45,749 --> 00:05:44,000
second prize but maybe by getting some

166
00:05:47,510 --> 00:05:45,759
experience here integrating this payload

167
00:05:49,670 --> 00:05:47,520
that maybe will up my chances a little

168
00:05:51,270 --> 00:05:49,680
bit farther in the selection process i

169
00:05:52,710 --> 00:05:51,280
got pretty far a couple a couple

170
00:05:54,230 --> 00:05:52,720
selections ago got to the reference

171
00:05:55,510 --> 00:05:54,240
stage but

172
00:05:57,670 --> 00:05:55,520
never an interview

173
00:05:59,110 --> 00:05:57,680
all right well and so it's interesting

174
00:06:01,510 --> 00:05:59,120
that this a lot of people don't know

175
00:06:03,590 --> 00:06:01,520
about cases and so uh

176
00:06:07,350 --> 00:06:03,600
we're talking about this because this is

177
00:06:08,790 --> 00:06:07,360
one way one avenue for researchers

178
00:06:11,350 --> 00:06:08,800
whether they're from an academic

179
00:06:13,350 --> 00:06:11,360
institution or for a commercial company

180
00:06:14,950 --> 00:06:13,360
or even individuals in some cases to get

181
00:06:17,430 --> 00:06:14,960
research on the international space

182
00:06:18,870 --> 00:06:17,440
station it is a u.s official national

183
00:06:21,029 --> 00:06:18,880
laboratory

184
00:06:22,950 --> 00:06:21,039
and so uh can you tell us a little bit

185
00:06:25,110 --> 00:06:22,960
about how working with cases has been

186
00:06:27,590 --> 00:06:25,120
yeah it's been great i mean it's it's

187
00:06:29,909 --> 00:06:27,600
just like you know working gonna be just

188
00:06:32,230 --> 00:06:29,919
like if i went to oak ridge national lab

189
00:06:33,990 --> 00:06:32,240
to do do my research up there um

190
00:06:35,590 --> 00:06:34,000
battelle runs that for for the us

191
00:06:36,710 --> 00:06:35,600
government cases does the exact same

192
00:06:40,150 --> 00:06:36,720
thing for the international space

193
00:06:41,749 --> 00:06:40,160
station essentially um so it's been fun

194
00:06:45,110 --> 00:06:41,759
i'm just learning to meet

195
00:06:47,270 --> 00:06:45,120
all the people down there um so i plan

196
00:06:48,870 --> 00:06:47,280
actually i'm gonna be there in two weeks

197
00:06:50,629 --> 00:06:48,880
for uh spring break just happened to be

198
00:06:52,790 --> 00:06:50,639
down there with my daughter so maybe

199
00:06:54,790 --> 00:06:52,800
we'll zip over to the to the cape to to

200
00:06:56,790 --> 00:06:54,800
see them and see the place

201
00:06:58,070 --> 00:06:56,800
all right well judd reedy thank you so

202
00:07:00,390 --> 00:06:58,080
much for joining us today and

203
00:07:01,670 --> 00:07:00,400
congratulation on your experiment being

204
00:07:03,430 --> 00:07:01,680
selected for

205
00:07:04,710 --> 00:07:03,440
tests on the international space station

206
00:07:06,710 --> 00:07:04,720
we'll look forward to hearing the

207
00:07:09,430 --> 00:07:06,720
results of your research thank you very

208
00:07:11,990 --> 00:07:09,440
much kelly i appreciate it

209
00:07:13,909 --> 00:07:12,000
all right that was judd reedy uh who is

210
00:07:15,909 --> 00:07:13,919
working with an experiment that's been

211
00:07:18,070 --> 00:07:15,919
selected now by the center for the

212
00:07:19,589 --> 00:07:18,080
advancement of science and space

213
00:07:21,830 --> 00:07:19,599
to fly on the international space

214
00:07:23,589 --> 00:07:21,840
station in a year or so that's going to

215
00:07:25,909 --> 00:07:23,599
look at how to make

216
00:07:27,749 --> 00:07:25,919
better and three-dimensional