WEBVTT FILE

1
00:00:01.600 --> 00:00:03.933
On November 1st, 2023,

2
00:00:03.933 --> 00:00:09.133
NASA's Lucy spacecraft will fly by a small Main Belt
asteroid named Dinkinesh.

3
00:00:09.133 --> 00:00:14.133
This flyby was added to Lucy's list of targets
in January 2023.

4
00:00:14.133 --> 00:00:16.566
There will now be ten asteroids that the Lucy mission

5
00:00:16.566 --> 00:00:20.533
will explore on its record breaking tour.

6
00:00:20.533 --> 00:00:23.166
Dinkinesh will be the smallest Main Belt asteroid

7
00:00:23.166 --> 00:00:25.900
to have ever been well-imaged by a spacecraft,

8
00:00:25.900 --> 00:00:29.800
registering at only about a half-mile in size.

9
00:00:29.800 --> 00:00:31.766
The primary purpose of this encounter

10
00:00:31.766 --> 00:00:36.733
is to test the spacecraft's Terminal Tracking System,
which will keep Lucy's instruments

11
00:00:36.733 --> 00:00:41.366
pointing at the asteroid
as it flies by at 10,000 miles per hour.

12
00:00:41.366 --> 00:00:45.600
This test may prove crucial
to the overall success of the mission.

13
00:00:45.600 --> 00:00:49.200
Even with the best Earth-based observations
of these distant objects,

14
00:00:49.200 --> 00:00:52.466
there will still be some uncertainty
about precisely where each target

15
00:00:52.466 --> 00:00:56.233
will be as Lucy approaches it. During its journey,

16
00:00:56.233 --> 00:01:01.533
Lucy will utilize its L’LORRI instrument
for optical navigation to improve that knowledge;

17
00:01:01.533 --> 00:01:05.866
but uncertainties as large as a hundred miles may still remain.

18
00:01:05.866 --> 00:01:08.200
If nothing was done, the science instruments

19
00:01:08.200 --> 00:01:13.033
could completely miss the asteroid during the closest approach.

20
00:01:13.033 --> 00:01:14.133
It's for this reason

21
00:01:14.133 --> 00:01:16.633
that Lucy uses the Terminal Tracking System

22
00:01:16.633 --> 00:01:20.166
to image the Trojan targets
in the final hours of an approach,

23
00:01:20.166 --> 00:01:23.133
and to autonomously update the spacecraft's onboard

24
00:01:23.133 --> 00:01:27.433
knowledge of the location of the asteroid in space.

25
00:01:27.433 --> 00:01:31.466
This in turn, allows the instruments to aim with precision,

26
00:01:31.466 --> 00:01:36.900
which will facilitate better
imaging and measurement of these small bodies.

27
00:01:36.900 --> 00:01:38.800
The Dinkinesh asteroid presents

28
00:01:38.800 --> 00:01:42.400
the perfect opportunity to test this system.

29
00:01:42.400 --> 00:01:44.400
The geometry of this encounter,

30
00:01:44.400 --> 00:01:49.033
particularly the angle that the spacecraft approaches
the asteroid relative to the Sun,

31
00:01:49.033 --> 00:01:52.566
is very similar to the mission's planned
Trojan asteroid encounters.

32
00:01:52.566 --> 00:01:57.266
This allows NASA to essentially carry out
a dress rehearsal under similar conditions

33
00:01:57.266 --> 00:02:00.800
well in advance of the spacecraft's main scientific targets.

34
00:02:00.800 --> 00:02:06.566
It's also a full year and a half earlier
than the already planned Donaldjohanson asteroid encounter,

35
00:02:06.566 --> 00:02:12.766
which will serve as a more intricate and complex
test of the spacecraft's systems and instruments.

36
00:02:12.766 --> 00:02:14.666
And since Dinkinesh is much smaller

37
00:02:14.666 --> 00:02:18.500
than any of the Trojan asteroids
that Lucy will be collecting data on,

38
00:02:18.500 --> 00:02:23.300
this test is meant to challenge
the Terminal Tracking System’s capabilities.

39
00:02:23.300 --> 00:02:25.833
It's likely that the system will lock on to Dinkinesh

40
00:02:25.833 --> 00:02:28.800
for only a few minutes before closest approach,

41
00:02:28.800 --> 00:02:32.800
compared to the hour or more
it will have for the Trojan targets.

42
00:02:32.800 --> 00:02:35.233
So, no matter the end result,

43
00:02:35.233 --> 00:02:39.066
this flyby will provide
Lucy's science team and flight engineers

44
00:02:39.066 --> 00:02:43.166
with important insights
into how the tracking system can function.

45
00:02:43.166 --> 00:02:47.433
After the encounter with Dinkinesh, Lucy's orbit around
the Sun will bring it back

46
00:02:47.433 --> 00:02:52.100
towards Earth for its second gravity assist in December 2024.

47
00:02:52.100 --> 00:02:59.000
That assist will send the spacecraft off
to meet its main objectives among the Trojan asteroids.

48
00:02:59.000 --> 00:03:01.433
While the primary purpose of the Dinkinesh encounter

49
00:03:01.433 --> 00:03:03.000
is an engineering test,

50
00:03:03.000 --> 00:03:07.866
the data collected may also provide insight
on the relationship between the Main Belt asteroids

51
00:03:07.866 --> 00:03:10.866
and near-Earth asteroids.

52
00:03:10.866 --> 00:03:14.666
It's an exciting addition to Lucy's groundbreaking mission.