Archive for the ‘Uncategorized’ Category

Crawler-Transporter

October 28, 2009

The Crawler-Transporter that brought Ares 1X and its Mobile Launcher (MLP) to the pad last week is one of two that were originally built in the mid-60s for the Saturn series of flights, and have been in use since, for Saturn, Shuttle and now Ares.

Crawler-Transporter near the VAB

There are really two alternatives to transporting rockets vertically to their launch position. The first is to build the rocket horizontally, move it horizontally and hoist it erect at the pad. The massive scale of the Saturn boosters really rules this out. The second option is to build the rocket at the pad. Several factors are against this: weather at the Cape is pretty volatile – hurricane winds, rain, lightning – holding up work; the rate of launches required to meet the end of ’69 deadline meant that having a rocket under construction at the pad would lead to unacceptable congestion.

So the solution was to build a massive Vehicle (initially Vertical) Assembly Building (VAB), construct each rocket inside, out of the weather and transport the rocket to the pad from there. But, again, the massive scale of the Saturn boosters meant this was no trivial problem.

Barges on canals (problems with stability and wind)  and railways (difficulties with rail stability and cornering) were both considered as options, but the solution settled on was to transport the rocket, MLP and Launch Umbilical Tower (LUT) by crawlers.

The coal miners of Ohio had been using massive tracked excavators to strip mine coal.

Bucyrus-Erie steam shovel crawler, Kentucky. Note man on top for scale.

These remain some of the biggest vehicles in the world. In February 1962 NASA engineers from the Launch Facilities and Support Equipment Office (LFSEO) were contacted by the Bucyrus-Erie Company who realised the potential of their massive machines to move launch vehicles.  The Marion Power Shovel Company won the tender, bidding 8 million dollars (competing with Bucyrus-Erie Company, its Ohio competitor, which has since bought Marion, who bid 11 million dollars) and built two wonders. Philip Koehring worked on the Bucyrus bid, and was immediately recruited by Marion to project-manage the massive engineering work.

The first test of the C-T took place in (July?) 1964, attended by several dignitaries and managers from NASA.

First test of the Crawler-Transporter

The image shows, from L:  Richard L. Drollinger, Director of Engineering, Marion Power Shovel Co.;  Theodor A. Poppel and Donald D. Buchanan, both of Kennedy Space Center;  S. J. Fruin, Executive Vice President and Philip Koehring, Project Engineer, both of Marion; and Kurt H. Debus, Center Director at Kennedy Space Center

Each of the two crawlers weighs in at 2700 tonnes, and is supported by four pairs of enormous caterpilar tracks, one at each corner. Each of these tracks has 57 shoes, 0.3 x 2.3m, each weighing nearly a tonne in themselves. The tracks are driven by 16 electric motors. Steering seems to be via three hydraulic rams which push the truck around on its guide tube.  The turning radius is 152 metres, only four times the vehicle’s length.

Crawler truck assembly

The platform which supports the MLP and vehicle has an area of 726 square metres or so, and can rise from 6m above the ground to 8m above ground level. This platform can be kept horizontal, even during the ride up the 5% slope to each pad.

The massive power needed to move such loads is supplied by a diesel-electric system. Generators with a combined power of 5500 kW supply motors, steering and hydraulic pumps. Despite this massive output, the speed of the C-T is limited to about 2mph (0.9m/s) when unloaded, and 1mph when loaded. Bearing in mind the cumbersome nature of its loads, that seems fast enough.

Bob Myers, Crawler Systems Engineer, in one of the cabs

The monster is driven from one of two cabs.  Controls seem very simple, belying the precision achievable:  the C-T must deliver the vehicle and MLP to the pad and lay it down gently within very tight limits.  It is said that the C-T can be moved forward and back in increments as small as 1/8 of an inch (about 3mm)!

So large is the crawler it has a control room inside, under the main deck.  Here engineers monitor and control the motors and generators that supply the electrical power for C-T and MLP systems.  The whole thing is surrounded by catwalks allowing engineers to access any part of the C-T and gain access to the MLP.

Schematic drawing of the Crawler Transporter

Control room windows

The first Crawler transporter ready for service, Jan 1966

A while ago I enjoyed building a Saturn V scale model (and here).  While researching this I’ve found there is a model of the C-T you can build as well.  It looks fantastic, although it is 1:144, so not compatible with my original Saturn V.  However, if this modeller ever finishes this and gets the plans out there I’ll be occupied for ever, but happily!

1:96 Crawler model detail

Sources:  All the sources are referenced in text links or image links.  Most useful, and recommended reading for an understanding of the development of Cape Kennedy Space Center and its hardware is ‘Gateway to the Moon’ by Benson and Faherty.  This book is the first 14 chapters of Moonport: A History of Apollo Launch Facilities and Operations, 1978, part of the NASA History Series.

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Beyond Apollo

September 15, 2009

I realise I haven’t written much here of late, despite a fantastic visit to Apollo sites in the summer.  The fact is, I’ve been reading David SF Portree’s fantastic Beyond Apollo site over the last few months, and just can’t match him for interest and depth.  This leaves me feeling unable to make a decent contribution.  I’m sure I’ll get over it, but blogging isn’t my life anyway!

Please visit David’s blogs.  He’s been talking of deleting his blogs lately, but I hope he doesn’t.

Apollo LM descent stages imaged!

July 18, 2009

The Lunar Reconnaissance Orbiter recently began imaging the surface of the Moon in unprecedented detail. Astonishing images of 5 of the 6 landing sites for Apollo have been released and at last we can resolve the hardware left behind by the 12.

Apollo 14 landing site

Apollo 14 landing site

This image of the Apollo 14 landing site, where Shephard and Mitchell landed is remarkable for its detail, showing both the descent stage (middle right) and to the left a little the ALSEP, or part of it and the trail the astronauts left as they walked between the two.

The Apollo 17 image is interesting.  I’m not sure, but wonder if the rover (or rather its shadow) can be seen to the left of the descent stage here, left after famously allowing Ed Fendell to capture the liftoff of the ascent stage taking Cernan and Schmitt from the Moon for the last time.

Apollo 17 Landing Site

Apollo 17 Landing Site

What’s even more exciting about these images is that there is better to come.  The LRO is yet to achieve its final orbit and resolution (just over 1m per pixel currently) is set to double at least.  Wow!

Apollo Umbilical

February 19, 2009

I can’t be bothered to figure out how to embed this video.  It shows NASA engineers using the Apollo umbilical as a model to inform their design of the Orion umbilical.

Since Orion is reusable, I wonder if they’ll depart from the guillotine style of the Apollo umbilical.  I’d expect that to be more reliable, and it should be trivial to put replaceable connectors just inboard of the cut point so that the cables/pipes can be replaced easily.

Rover Video

January 22, 2009

Nice to get a look inside.

Rover video

Small Pressurized Rover

October 26, 2008

NASA have been testing ideas for Lunar Rovers.  You’ll remember what a success the Rovers for Apollos 15-17 were.  These were ideal for exploration as the astronauts could stop and get off when they pleased to collect samples as the need arose.  It was neatly packed into one of the quadrants of the descent stage of the LM, and was easily deployed.

It’s good to see radical new ideas being considered and this Small Pressurised, sorry, Pressurized Rover (SPR) seems to improve on the original idea in several ways:

  • a shirt-sleeve cab for driving, minimising the time astronauts need to stay suited up
  • egress in, apparently, just 10 minutes via suits which stay outside…
  • …minimising the amount of dust brought inside
  • the option to drive from outside while suited up
  • a 2.5cm layer of ice over part of the craft to act as a solar-storm shield and heat sink
  • improved manouverability

There’s still only room for two (four at a pinch), but the range is proposed to be a massive 240km.

It’s not clear how this will get to the Moon, nor can I see how the large docking hatch can be used to dock with an ascent stage much further from the ground, but I very much like what I see.

Clearly nasty accidents can happen even in Earth testing.  The astronaut on the left here has lost the legs of his suit, or perhaps he just managed to inside-out them on the way back into the Rover?

Saturn V launch

October 25, 2008

While I’m at it embedding videos, what about this one?  We’ve all seen this launch sequence so many times, but this is a case of seeing not being enough for believing.  It’s hard to imagine the forces (more than 33 000 000 N) lifting this 3000 tonne machine into the air. 

Constellation Spacesuit

June 19, 2008

NASA have contracted for new spacesuits to be used on Orion missions. They look like hard shell suits, mainly, and the innovation here seems to be in a modular approach which will allow a capsule/EVA suit to be modified for Moonwalking.

Have a look at NASA’s page and New Scientist’s page. See what you think.

Hammer & Feather II

April 18, 2008

Time I posted some video of my favourite astronaut experiment. This is such a simple demonstration, and Dave Scott carries it off well. He actually carried two feathers with him as he wasn’t sure how the static building up as he moved around would allow him to drop the first one. He didn’t need it, of course, but no-one knows what happened to the second feather. Do they?

Rocket Science

December 17, 2006

I’ve been enjoying making this 1:96 card model of a Saturn/Apollo booster. At first I got it completely wrongOops!  Start again! as there are very few instructions, and really just the photos to go on. However, the models are very accurate and good fun to make. I used to make Airfix models when I was a teenager, but this is much less modelling by numbers and I am forced to learn a huge amount about the rocket.

Apollo model 17.12.06I’ve been reading the Saturn V News Reference as a way of finding out more. I’ve always been stunned by the sheer scale of everything – the 10m rocket diameter, and especially the F1 engines. Making the model also highlights this, especially now I’m getting to the top of the stack and finding the Apollo spacecraft to be very fiddly indeed!

I’ve been using the Saturn V blueprint poster, produced by Boeing, as a reference. This prints brilliantly, and I’ve managed to get a very large (~1m long) version printed, white on a blue background. It looks great. The Apollo Maniacs website is a superb resource on all things Apollo.

One small niggle: the decals don’t seem to match any of the flight articles, although there is an Apollo 11 version. I’m not really that bothered.Apollo launches

I was going to start with the 1:48 version of the model. This would be truly huge. The 1:96 model will be about 120cm tall. Maybe one day…

More about this when I’ve finished, probably.