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LRV Performance

Copyright © 2010 by the Editors of Working on the Moon.
Last revised 9 January 2010.

Header 3


Text

Apollo 16 Traverse Segments


Location
Ground Elapsed Time (hhh:mm:ss)
Odometer (km)
Range (km)
Battery (amp-hrs)
Travel Time (mm:ss)
Odom. Diff.

Odom. Diff /
Trvl.Time
MapDist.

MapDist. / Trvl.Time
Notes

EVA-1


ALSEP Depart 122:59:06 0.1
0.1
118, 118
24:48
1.9 km

4.8 km/hr
1.6 km

3.9 km/hr
Caution driving down-Sun. LM map location uncertain till they get to Plum.  Brief, unplanned stop at Halfway Crater because of nav. undertainty.
Station 1 Arrive 123:23:54 2.0
1.4
nr = not reported
Station 1 Depart 124:14:32 6:15
0.8 km

7.7 km/hr
0.7 km

6.7 km/hr
Followed outbound tracks so less caution despite poor up-Sun visibility.  John mentions in the mission report that he did some tacking to improve visibility.
Station 2 Arrive
124:20:47 2.8
0.8
nr
Station 2 Depart
124:48:20 5:47
1.0 km

10.4 km/hr
0.9 km

9.3 km/hr
On the return to the LM, they stopped near the ALSEP so that Charlie could film John doing the Grand Prix, which involved John driving the LRV toward the LM and back.  John drove for about 25 seconds toward the LM, reporting a max speed of 10 km/hr along the way.  He then turned and drove back in about 25 seconds.  The distance driven was no more than 140 meters.  He then did a second run.  In total, each of the runs took about 1 min 05 seconds.

*The odometer value used at the ALSEP when they get back is the value given later at the LM minus 0.4 km, total, for the two Grand Prix runs and the 0.1 km return to the LM.
ALSEP
Arrive
124:54:07
3.8*
0.1
nr
LM Arrive
125:09:43
4.2
0
108, 105
-
-
-

EVA-1 Totals
Driving Time:  40:00 (est.)
Odometer distance and speed:  4.2 km, 6.3 km/hr
Map distance and speed:  3.2 km, 4.8 km/hr

EVA-2



Ground Elapsed Time (hhh:mm:ss) Odometer (km) Range (km) Battery (amp-hrs) Travel Time (mm:ss)
Odom.Diff

Odom.Diff / Trvl.Time
MapDist.

MapDist. / Trvl.Time
Notes
LM Depart
143:31:40 0
0
108, 105 from EVA-1 Close-out 23:56
5.2 km

8.7 km/hr
3.1 km

7.8 km/hr
Figure 6-6 from the Apollo 16 Preliminary Science Report shows the various station locations and approximate locations from which Charlie took various traverse photos.  John and Charlie drove SSE from the LM, climbed up onto Survey Ridge and drove SSW along it before heading to a point at the base of Stone Mountain directly north of Station 4.  The started climbing at about the indicated place whereCharlie took photo 17918.  Their average speed along their actual path is necessarily greater than the 7.5 km/hr range rate.
Base of Stone Mountain
143:55:36 nr
3.0
nr
Base of Stone Mountain
143:55:36 nr
3.0
nr
11:53
1.2 km

6.1 km/hr
Station 4 and the approximate spot where Charlie took 17918 are shown in a labeled detail from topographic map LTO78D2S1(50) (5.7 Mb) indicates that they were driving cross-slope and climbed about 145 meters in 1.1 km.  The slope they experience is about 7.5 degrees.
Station 4 Arrive
144:07:29 5.2
4.1
100, 100
Station 4 Depart
145:04:22
5:08
0.7 km

8.2 km/hr
0.7 km

8.2 km/hr
Followed their outbound tracks partway downhill.

Young: Ya-ho-ho-ho-ho.  (Pause)  Look at this baby (meaning the Rover).  I'm really getting confidence in it now.  It's really humming like a kitten.
Duke: Oh, this machine is super.
CapCom Tony England: Probably a good idea you couldn't see how steep it was going up.
Young: Darn right it was.  (Pause)  Okay.  I've got the power off, and we're making 10 kilometers an hour.  Just falling down our own tracks.  (Pause)  Uh-oh.
Duke: Almost spun out.
Station 5 Arrive
145:09:30
5.9
3.5
100, 100
Station 5 Depart
145:58:40
6:39
0.8 km

7.2 km/hr
0.5 km

4.5 km/hr
Young: Okay, we're riding at idle (meaning that he is not applying any power to the wheels), and she's picking up speed ... I'm just glad that we don't have that watch-the-Rover-go TV.  (Laughing)  Because I don't think we'd be going.  (Pause)

John is probably saying that, if Houston had real-time TV of this drive, the NASA managers would be having heart-failure and would make the crew stop and walk down the mountain.

At 146:03:32, they turn left and drive west along a bench to find a suitable crater for sampling.
Station 6 Arrive
146:05:19
6.7
3.1
100, 95
Station 6 Depart
146:29:22
10:46
1.2 km

6.7km/hr
0.8 km

4.5 km/hr
They drive west for most of this segment, then turn south to climb a ridge.  This probably slows them somewhat, but an incorrectly-set Rover circuit breaker also contributes.  Houston helps them correct the problem before they leave Station 8
Station 8 Arrive
146:40:08
7.9
2.9
95, 95
Station 8 Depart
147:48:15
3:09
*
0.5 km

9.5 km/hr
*The nav system is not working properly, probably because of the various changes in switch and circuit breaker setting made while diagnosing the drive power problem.
Station 9 Arrive
147:51:24
*
*
90, 90
Station 9 Depart
148:29:45
24:28
*
2.6 km

6.4 km/hr
*They notice the nav system errors during this segment. They do the Station 10 activities near the ALSEP. 
Station 10 Arrive
148:54:13
*
*
65, 110
EVA-2 Totals
Driving Time:  86:00 (est.)
Odometer distance and speed:  11.3 km, 7.9 km/hr
(map distance plus 10% for the last two segments)
Map distance and speed:  9.4 km, 6.6 km/hr

EVA-3 outbound

Location Ground Elapsed Time (hhh:mm:ss) Odometer (km) Range (km)

Bearing (degrees east of north)
Battery (amp-hrs) Travel Time (mm:ss)
Odom.Diff.

Odom.Diff. / Trvl.Time
MapDist.

MapDist. / Trvl.Time
Notes
LM Depart
166:09:13
0
0

0
60, 115
13:02
nr
1.7 km*

7.8 km/hr

They climb a ridge immediately north of the LM, then back down into a "big, sag-type area", and continue north to the elevated rim of Palmetto Crater and along the rim toward End Crater.

*Map location directly from LRV nav. readout of range and bearing to the LM.  On Figure 3.6.2-8a in Final Lunar Surface Procedures, the LM is at CB.1/80.6 and their location on the Palmetto rim is CK.4/82.5
Palmetto rim
166:22:15
nr
1.7

193
nr
Palmetto rim
166:22:15 nr
1.7

193
nr
14:13
nr
2.0 km*

8.4 km/hr


England: Y'all are making some outstanding time there.
Duke
: It's really easy going, Tony.  (Hears Tony)  Well, he's got it full blower at 11 clicks, and we're just going over an undulating terrain.

*Map location directly from LRV nav. readout of range and bearing to the LM.  Their map location at the end of this segment is CV.5/82.5.

Base of North Ray ridge
166:36:28
nr
3.7

186
nr
Base of North Ray ridge
166:36:28 nr
3.7

186
nr
2:09
nr
0.2 km

5.6 km/hr


At the start of this interval, they are just east of Station 13.  As can be seen in the contour map  from the North Ray chapter of the A16 Professional Paper, they climb about 25 meters over the next 200 meters, a slope of about 7 degrees.
Top of the 1st rise
166:38:37
nr
nr
nr
Top of the 1st rise
166:38:37 nr
nr
nr
5:46
nr
0.6 km

6.2 km/hr

Young: Okay.  (Pause)  We're on a relatively flat surface now

Over the next 450 meters, they
climb about 10 meters, on a slope of 1.3 degrees, and then finish with a climb of about 15 meters over the final 150 meter to Station 11, a slope of about 6 degrees.



As discussed in the ALSJ after 166:45:15,  the bearing and range puts them well inside the rim, about 250 meters north of their actuall location.  This unusualy-large difference may be due to wheel slippage during the climb up North Ray Ridge.
Station 11
Arrive
166:44:23
5.5 km
4.5 km

179
60, 115

EVA-3 Outbound Totals
Driving time:  35:10
Odometer distance(less 0.2 km) and speed: 5.3 km, 9.0 km/hr
Map Distance and Speed: 4.5 km, 7.7 km/hr


EVA-3 Return

Station 11 Depart
168:09:46
5.5 km
4.5 km

179
60, 115
7:53
1.0 km

7.6 km/hr
0.9 km

6.8 km/hr
They follow they outbound tracks downhill toward Station 13.

Duke: We can't see old (LM) Orion from here.  (Laughing)  This is going to be something going down this hill ... Look at that slope!  Be sure that you got the brakes on.  Tony, this is at least a 15-degree slope we're going down, and that Rover came right up it and you never even knew it.  (Pause)  Brake that beauty, John.  (Laughs)  Man, are we accelerating.  Super.
Young:  (To Tony) We've just set a new world's speed record, Houston;  17 kilometers an hour on the Moon.

At 168:14:31, they reach the top of the 1st rise.  They've done 0.6 km in 4:45, giving a speed of 7.6 km/hr.

On arrival at Station 13, the location error has reduced to 180 meters, perhaps because of John's use of the LRv brakes coming downhill.
Station 13 Arrive
168:17:39
6.5 km
3.8

184
50, 110
Station 13 Depart
168:46:33
6.5 km
3.8

184
50, 110
13:35
nr
2.0 km

8.8 km/hr
Nearing the rim of Palmetto, Charlie gives a range and bearing about a minute after he mentions that they are "passing End Crater".  That suggests that the nav system still thinks the LRV is north of its actual location, now by roughly 150 meters.  They are near CK.6/82.5
Palmetto
169:00:08
nr
1.9

192
nr
Palmetto
169:00:08 nr 1.9

192
nr 15:18
nr
1.9 km

7.5 km/hr
Station 10' is due north of the ALSEP

The segment from Station 13 to Station 10' covered sn odometer distance of 3.8 km, done in 28:53, at an average speed of 7.9 km/hr.
Station 10' Arrive
169:15:26
11.1 km
0.1

188
30, 120
EVA-3 Return Totals
Driving Time: 36:46
Odometer distance and speed:  5.6 km, 9.1 km/hr
Map distance and speed:  4.8 km, 7.8 km/hr



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