The Crawlers

01It dominates whatever is around it.

02You can feel as it comes by, you know, it shakes the ground a little bit.

03It would just amaze you at the size and the complexity of it.

04Think of something that's moving very slow, about .8 or .9 miles an hour, moving this big rocket down the road.

05It's fun to get up every day and come out and work on the crawler.

06Our universe is a wild and wonderful place.

07I'm Patti Boyd, and in this show, NASA is your tour guide.

08Rockets are what launch some of our heaviest and most far-reaching instruments into space.

09But what gets these rockets to their last destination on the ground, the launch pad?

10In this episode, we're exploring some of NASA's most powerful ground machinery, the crawlers.

11These one-of-a-kind, six-million-pound behemoths are what transport rockets and their mobile launch platforms, so that they can make their ascent into space.

12And the crawlers have a long history.

13You almost have to go all the way back to the beginnings of NASA here at Kennedy Space Center.

14That's where they built the launch vehicles.

15That's the crawlers' senior project manager, John Giles.

16The launch vehicles he's referring to are the rockets that would help NASA send humans to the moon for the first time.

17In the early 60s, NASA built the Saturn V rocket to carry out the Apollo missions.

18Saturn V was built upright and was a staggering 363 feet tall, with the Apollo spacecraft on top.

19That's taller than the Statue of Liberty.

20And somehow, the rocket had to travel from the vehicle assembly building to the launch pad, four miles away.

21Engineers at NASA scratched their heads.

22Well, how do you get it there?

23Something 300 feet long is a little tough to put on some kind of a flatbed truck and roll.

24You can't really put it on a barge or float it there.

25So, there were many studies done over the years, and they came up with the best way to get it there was to build this machine, this crawler-type machine.

26NASA needed a vehicle that could pick up millions of pounds and transport it for four miles, all while keeping it level.

27But NASA couldn't just call up any company to make a machine of this scale.

28They looked to an industry making some of the most powerful machinery out there, the coal mining industry.

29When you watch on TV and you see those giant dump trucks and those giant cranes that scoop up all the rock and stuff, the company that builds that type of equipment built this crawler.

30I think it's one of the most phenomenal pieces of engineering equipment ever designed.

31The Marion Power Shovel Company worked with NASA to make two of the most specialized pieces of equipment on the planet, Crawler 1 and Crawler 2.

32They both live at Kennedy Space Center in Florida, but Crawler 1 mostly hangs out in storage, while Crawler 2 gets to do the heavy lifting.

33And here to give you a tour of that crawler are two of its operators.

34There's Breanne Roloff, who just graduated with her bachelor's in aerospace engineering.

35Breanne, she's a blast to be around because she's young, and to her this is just so exciting and so neat.

36This is my first job out of college.

37And then there's Sam Dove.

38Sam's on the complete other spectrum.

39Sam is a senior driver.

40Ice water runs through his veins.

41Nothing phases him.

42I grew up in West Virginia as a farm boy, right?

43Did four years in the Air Force.

44Went to college.

45And then I was fortunate enough to get a job in the space program down here.

46I spent the first 10 years in design engineering.

47And then I became a crawler driver.

48So it wasn't just something I stepped off the street and did.

49Breanne and Sam both maintain and drive the crawlers.

50It's a truly unique job.

51And Breanne still vividly remembers the first time she saw a crawler.

52I just remember looking at it and being like, this is massive.

53It really reminded me of when you kind of take off in an airplane.

54You start to gain altitude and you see all of these things that you normally think of as being big.

55It's buildings and houses and cars and they kind of just shrink.

56And that's kind of what I remember thinking.

57Wow, people and cars look small compared to it.

58It's really not something comparable to what a lot of folks see.

59It's kind of like you took a steel one-story building and sheared off the top of it so it's completely flat.

60A steel box, basically.

61A steel box that's bigger than a baseball field.

62The crawler's platform, which needs to be big enough to accommodate a launcher and rocket.

63Inside the steel box, below where the cargo would sit, is a whole host of important things to keep the crawler going and to keep it level.

64Cables, fans, motors, pumps.

65And the crawlers don't move on wheels.

66But on tracks, like a tank, there are eight total tracks.

67If you think of a giant bulldozer, there'll be one on each corner.

68These tracks are heavy duty.

69The tracks are made up of little segments.

70Well, the crawler segments are called shoes and they're big.

71They're six feet long and about, I think, almost 18 inches wide.

72And they weigh 2,000 pounds per shoe.

73With 456 shoes on each crawler, the shoes alone weigh almost one million pounds.

74Once you add up the rest of the equipment on the crawler, the total weight comes to 6.5 million pounds.

75And that's without any cargo on top.

76That's how big the crawler is.

77Once you add the rocket and the launcher, that's when things get really heavy.

78You know, you're looking at almost 25 million pounds.

79I really don't think I fully understand how heavy that is.

80That's a lot of weight on the ground.

81So you may be thinking, can a normal road withstand the pressure of a crawler?

82So when the crawlers were first built, they did try to roll them on roads out here.

83Needless to say, the asphalt roads did not fare so well.

84We put some cracks in them.

85So it just tore it up.

86Once again, NASA engineers and contractors had to get creative and design something that could support the hefty vehicle.

87Just like the crawlers, the crawler way is one of a kind.

88Everything's special about the crawler way.

89I mean, first of all, it's the size of an interstate road, right?

90You have two lanes on one side, two on the other, and the median.

91But what's most special about the crawler way is what it's made of.

92It's filled with crushed and compacted limestone, hydraulic fill under that.

93And on top of that, about eight to ten inches of gravel.

94That gravel is actually Tennessee river rocks.

95That's what the tracks make contact with.

96And the river rock becomes the sacrificial component because the crawler doesn't have shock absorbers like your car does.

97And when you're carrying a multi-million, multi-billion dollar launch vehicle on top, you don't want to shake it to death while you're rolling it.

98So the crushing of this rock attenuates the vibration.

99As more and more rock crushes into finer pieces, it has to be replaced to make sure it can continue to be a good shock absorber for the crawler.

100Rollout days, or when the crawler actually makes a trip, are big affairs.

101The team, composed of about 30 engineers, gathers four hours before the roll, around 8 p.m.

102They go over the mission, talk safety, and discuss who is in charge of each task.

103Then the team fires up the engines, which take 45 minutes just to heat up.

104The first thing that lets you know we're starting up is you use compressed air to start these large engines, and it just goes...

105And it just gets louder and louder.

106And then the second the engines start, that noise goes away, and then you'll just hear this...

107And some black smoke comes out.

108Then the rest of the systems get going.

109The pumps, the lubrication system, the hydraulics, the fans, all with their unique sounds.

110It really has sounds all its own.

111You really need to be attuned to what those sounds sound like.

112If it's not running right, you can almost immediately tell you need to start looking at something.

113If everything is running properly, the crawler will pick up its freight by rolling right under the launcher.

114It's usually around midnight when the crawler begins its journey to the pad.

115To transport a rocket to the launch pad, the team breaks out into their individual posts.

116There are technicians on the ground constantly checking the position of the crawler.

117If you're walking alongside of it, it's dusty and there's bugs flying around.

118And then you just hear these shoes that just constantly just slapping on the ground.

119And it just never goes away.

120They just keep rolling.

121And then there are the people on board.

122There's probably about at least ten people on the crawler at any time.

123You'll have three engineers that are actually operating something at one time.

124The test conductor, the leveling system operator, and a driver.

125All of those people have backups.

126People to switch out with if they need a break.

127This is very important given that the journey to the pad takes eight hours.

128Why does it take so long to travel only four miles?

129Well, the crawler rarely goes faster than one mile per hour.

130The speedometer shows zero to two.

131Driving such an enormous vehicle is an experience few of us will ever have.

132But Sam tries to explain what it's like.

133Driving the crawler is something like driving your car except it's very slow.

134You know, you're constantly watching your speed because you can't just do a, you know, drift through a curve like a NASCAR race car can.

135And with your car, any inputs you make to the steering wheel, you immediately see that, right?

136Because you're moving at a much faster speed and it's a smaller vehicle.

137With the crawler, you have to think ahead.

138Going so slowly might seem like it would be monotonous.

139Oh, no, no, no.

140Boredom is not something that you have on the crawler, right?

141You're watching where you're going, where you've been, where you're at, the speed, what you're steering.

142Because if the crawler catches you not paying attention, it'll remind you.

143Driving the crawler can be tricky as is.

144But the team has to be aware of other things that might obstruct rollout, like forces of nature.

145Florida, where the crawlers are located, is the number one hurricane and lightning capital in the U.S.

146We don't like rolling, carrying very tall things during thunderstorms and lightning storms.

147Lightning and a rocket are not my favorite combination.

148So the way to get around that is we start rolling very early in the morning.

149That's to avoid the afternoon, when storms are most likely to strike.

150The weather is one thing to watch out for.

151But another obstacle involves things on the ground.

152Because the Kennedy Space Center rests on a wildlife refuge.

153You are constantly on the lookout for wild animals.

154You know, we see bobcats.

155Turtles.

156Snakes.

157Wild hogs.

158Coyotes are starting to come in here.

159You kind of just sit there and you're like, oh, please don't.

160Please don't come into the crawler way.

161Sometimes, though, pleading doesn't work.

162Animals can get in the path of the crawler.

163And that slows the team down.

164There was like a 10 or 12 foot gator that was under one of the trucks.

165And, you know, we had to call the wildlife officer to come and pull that gator out.

166And he was kind of like the crocodile hunter there, you know, like Steve Irwin was.

167He just reached under and grabbed that alligator by the tail, pulled him up, trussed him up, and took him to another part of the space center.

168It was the darndest thing you ever saw.

169And off we went.

170And then there is the tale of the tortoise and the crawler.

171Less well known than the tortoise and the hare.

172One time we were going up the pad slope and I noticed a tortoise.

173They dig burrows in the ground here.

174And this tortoise happened to come out of his hole while we were rolling.

175This vibration that we're making kind of got him a little uneasy.

176So he starts walking around.

177The tortoise and the crawler were both heading up the ramp side by side.

178And this is a true statement.

179The tortoise beat us to the top of the pad.

180That's how slow we go sometimes.

181I guess slow and steady doesn't win the race after all.

182The whole ride down the crawler way is leading up to the most crucial and technical moment when the crawler approaches the launch site.

183It has to go up a ramp called the pad slope and place the rocket with its launcher precisely onto its mounts.

184And that's when things get really exciting but also things get very focused.

185By far the most stressful part of any role is going up the pad.

186Everything's got to be perfect.

187We got to do this right.

188Everybody's got to work as a team.

189Can't get anything wrong.

190The first time I was on the crawler when we pulled up the pad slope.

191And I wasn't even driving.

192I was just observing.

193But seeing other engineers, the more experienced ones, pull up, I felt nervous just being in there for them.

194I was like, oh my gosh.

195When we go up the slope, it's all hands on deck.

196Everybody is stationed in a certain area.

197All of our engines have to be running at their peak performance.

198There'll be technicians standing by them watching every gauge and every fluid level on them as we're rolling.

199If we were to go up that ramp and then lose power for some reason, we could roll backwards.

200The crawler is on a five-degree slope.

201But the rocket needs to stay completely level.

202So the jacking and equalization equipment kick into high gear.

203By that time, the crawler is going even slower than normal.

204Then once you get up close, you jack up to the proper height to go over the mounts.

205And then you get yourself straight and we use a laser to do that.

206And then once you're all lined up left and right and you're high enough, then you get over everything.

207And you get stopped and then you set the whole thing down on the mounts and it fits within a quarter inch.

208After a successful rollout, everyone on the team can breathe a sigh of relief and take a moment to celebrate.

209They've just taken a rocket on its last earthbound leg of its journey before it launches into space.

210We have a tradition when we complete rollout.

211We pop open a bag of chips and somebody breaks out a jar of salsa.

212Gosh, everybody comes in off the pad, the crawlers, to get chips and salsa.

213So it's just something you need to experience.

214When NASA first conceived of the crawlers, it wasn't clear how long they would stay in use.

215By now, the crawlers have long outlived the lifespan of most vehicles.

216And that's because the crawler operators spend most of their time maintaining and upgrading them.

217It's over 55 years old now.

218And she was not designed to last this long.

219So the reason it has lasted this long is because it's so well maintained.

220The crawlers have been there almost since the beginning of NASA, starting with the Apollo days.

221Now the crawler team is getting ready for another mission to bring humans back to the moon.

222The Artemis 1 mission.

223For this mission, the crawler will need to move some of the heaviest loads it ever has.

224To prepare, the team has had to upgrade the crawler.

225New, more powerful generators and cooling systems.

226Bigger bearings.

227There's a lot at stake.

228Because without the crawler, there is no launch.

229It's a big responsibility, but it's really great because if there's something going on in the Space Center, you know, that's really important.

230And the crawler is usually right in the middle of it.

231What we're doing here is just, it's so important for the country, I believe.

232And you've got to have to have this machinery to be able to launch that rocket.

233And it's just great to be a part of it.

234Engineers like Sam and John have maintained the crawlers throughout the space shuttle program.

235And we'll need them again when we return to the moon and go on to Mars as part of the Artemis era.

236And young engineers like Brianne will keep the crawlers functioning for wherever NASA goes next.

237As long as there are rockets that need to get from point A to point B, the crawlers will keep rolling.

238This is NASA's Curious Universe.

239This episode was written and produced by Margo Wall.

240The Curious Universe team includes Maddie Arnold, Michaela Sosby, and Vicki Woodburn.

241Our executive producer is Katie Atkinson.

242Special thanks to Laura Aguiar, Ryland Hegey, Lorne Maythry, Daryl Nail, Madison Tuttle, Tracy Yates, and the Kennedy Space Center.

243If you liked this episode, please let us know by leaving us a review, tweeting about the show at NASA, and sharing this episode with a friend.

244Still curious about NASA?

245You can send us questions about this episode or a previous one, and we'll try to track down the answers.

246You can email a voice recording or send a written note to nasa-curiousuniverse at mail.nasa.gov.

247Go to nasa.gov slash curiousuniverse for more information.