1
00:00:00,060 --> 00:00:05,009
The SWEAP investigation consists of
three separate instruments and a central

2
00:00:05,009 --> 00:00:09,840
electronics box most of the instruments
within sweep sit on either side of the

3
00:00:09,840 --> 00:00:14,130
spacecraft stare out over the entire sky
and make maps of all the different

4
00:00:14,130 --> 00:00:17,940
particles and what energies they're
moving at what types of particles they

5
00:00:17,940 --> 00:00:23,070
are the purpose of sweep is to measure
the bulk of the solar wind and a solar

6
00:00:23,070 --> 00:00:26,670
atmosphere one of the biggest questions
we want to resolve with Solar Probe is

7
00:00:26,670 --> 00:00:29,670
how the corona in the solar wind are
heated in order to do that we need to

8
00:00:29,670 --> 00:00:34,350
see if there are waves that are coming
from the Sun and depositing energy

9
00:00:34,350 --> 00:00:38,700
within the solar atmosphere in the solar
wind so we have a series of sensors

10
00:00:38,700 --> 00:00:44,579
across the spacecraft that will collect
individual particles electrons fully

11
00:00:44,579 --> 00:00:48,719
ionized hydrogen helium which we call
protons and alphas and other minor ions

12
00:00:48,719 --> 00:00:54,030
and make maps of the number of particles
as a function of their speed and energy

13
00:00:54,030 --> 00:00:59,070
and type we take those maps on the
ground and we can interpret them to

14
00:00:59,070 --> 00:01:03,539
figure out the temperature the density
the pressure of the solar wind and the

15
00:01:03,539 --> 00:01:07,530
solar atmosphere on the RAM side of the
spacecraft so that's in the shadow of

16
00:01:07,530 --> 00:01:11,580
the heat field in the direction that
Solar Probe is moving around the Sun we

17
00:01:11,580 --> 00:01:17,159
have Span A. Span A looks ahead of the
spacecraft it has an electron and an ion

18
00:01:17,159 --> 00:01:21,840
instrument and they can see the entire
sky on that side of the spacecraft on

19
00:01:21,840 --> 00:01:26,640
the other side the anti ram side of the
spacecraft we have Span B which

20
00:01:26,640 --> 00:01:31,710
basically looks behind our direction of
motion Span a and Span B are each able

21
00:01:31,710 --> 00:01:35,909
to take an inventory of electrons coming
from any direction in the sky their

22
00:01:35,909 --> 00:01:40,530
fields of view stitch together like the
seams on a baseball the spans combined

23
00:01:40,530 --> 00:01:44,610
to give us a field of view that covers
nearly the entire sky and we have one

24
00:01:44,610 --> 00:01:47,759
large gap in our field of view and it's
produced by the heat shield at the front

25
00:01:47,759 --> 00:01:50,640
of the spacecraft
so we have the Solar Probe Cup is the

26
00:01:50,640 --> 00:01:54,869
final instrument within SWEAP. The Solar
Probe cups sits on a strut it looks

27
00:01:54,869 --> 00:01:58,950
around the heat shield and faces
directly into the Sun when our solar

28
00:01:58,950 --> 00:02:02,280
wind or solar atmosphere comes blowing
into the cup

29
00:02:02,280 --> 00:02:06,390
if those particles which are charged
don't have enough energy they get

30
00:02:06,390 --> 00:02:10,289
reflected out by that electric field
we've set up the particles with enough

31
00:02:10,289 --> 00:02:13,530
energy to make it past the
could feel come in and strike a plate

32
00:02:13,530 --> 00:02:18,480
and we record the current all we have to
do in an individual measurement is sweep

33
00:02:18,480 --> 00:02:22,110
in voltage and measure the number of
particles that can make it in as a

34
00:02:22,110 --> 00:02:25,890
function of the voltage that's sweep
when we interpret it lets us figure out

35
00:02:25,890 --> 00:02:30,840
the average speed direction energy
temperature density of individual

36
00:02:30,840 --> 00:02:35,770
populations of particles