MTA event, 2018-11-17

The Reaction Research Society (RRS) was glad to offer our Mojave Test Area (MTA) to UCLA for a series of tests of their liquid rocket. This was a private event, but Osvaldo and Elisa were there to witness a successful hot-fire series.

UCLA has been working on liquid rockets and this event was to test the improved version of their 650 lbf thrust LOX/ethanol engine. After validating minor modifications to the plumbing and an improved mechanism for their pneumatic valve actuators, UCLA expected good performance from this test with an expected burn time of 13.8 seconds and an expected total impulse of 9000 lbf-sec.

UCLA makes preparations on their liquid rocket, 11-17-2018 at the MTA

Other improvements include collecting better data. Data collection has been a challenge for many teams over the years. Tank, manifold and chamber pressure measurements were successful combined with thermocouples on the LOX lines for a better estimate of density and on the engine outer surface to anchor heat transfer assumptions. This temperature data has helped to better anchor their estimates of characteristic velocity (C*) and specific impulse (Isp). UCLA was not making direct flow rate measurements in this test, but has planned to do so in another forthcoming test.

UCLA’s liquid rocket in position

UCLA has also been giving their newer student team members opportunities on this project by passing knowledge gained from the more experienced members as turnover is a necessity with graduation.

UCLA liquid rocket hot fire way after sunset, 11-17-2018

Results from the hot-fire seemed to show that UCLA’s computational models were fairly close to actual performance. Total impulse was less than predicted at 8174 lbf-sec, average thrust at 467 lbf and peak thrust at 550 lbf, but a longer than predicted burn duration of 17.0 seconds.

These are good results but improvements can be made, particularly in getting direct propellant flow rate measurements. Both C* and Isp can be directly measured from propellant flow rate.

Further refinement of their assumptions based on this new hard data will help them in their next hot-fire planned for January 2019. The RRS is glad to assist UCLA and other universities with their liquid rocket projects at our Mojave Test Area (MTA). The RRS is ready to help UCLA take their next step in the new year.

We will surely discuss the results of this and the upcoming test of UCLA’s liquid rocket at the next RRS meeting, Friday, December 14th, 7:30pm, at the Ken Nakaoka Community Center in Gardena.

MTA launch event, 2018-08-18

The RRS had a small event at our private Mojave Test Area (MTA) on August 18, 2018, to allow Richard Garcia to test his liquid rocket motor. Richard built a pressure-fed, 1000-lbf kerosene-LOX motor including all of the static fire test stand equipment and control valves.

desert morning at the MTA

Richard Garcia reviews his list in the MTA blockhouse

Switch panel and electrical cabling

Richard had spent a good part of Friday and early Saturday getting his test stand mounted and ready. He had made arrangements to share the contents of a liquid oxygen dewar to supply the oxidizer he needed for his test with other RRS member, Sam Austin. Sam was also preparing to fire his liquid rocket motor at the Friends of Amateur Rocketry (FAR) site just south of the RRS MTA on this same day. Arriving early in the morning, I was glad to help Richard with the final preparations at the RRS MTA to start the initial checkouts and ultimately a successful hot-fire test.

Richard checks the wiring and pneumatic line connections

Richard’s 1000 lbf kerosene/LOX motor was designed for a chamber pressure of 300 psig and used a pintle-type of injector with an ablative lined chamber and graphite nozzle.

Richard Garcia tests both flow paths of his pintle injector in water flow

Ablative liner, G10, sits inside the combustion chamber of Richard Garcia’s 1000 lbf kerosene-LOX liquid rocket motor

Graphite nozzle within the chamber assembly of 1000 lbf kerosene-LOX motor

He brought his motor hardware to the January 2018 meeting, but now it was finally time to prove his design with a hot-fire test.

Richard shows his liquid rocket motor at the January 2018 meeting

Richard’s test used a high pressure nitrogen bottle to pressurize his propellant tanks, the left one for liquid oxygen (LOX) and the right one for kerosene. This regulated inert gas source also provided pneumatic pressure for the propellant valve actuators.

Richard’s static fire tanks and equipment mounted and ready for test, 2018-08-18

The top half of the thrust stand with the tanks and valves is fixed to the structure. The engine is suspended below and is secured to a plate which was mounted to an S-type load cell. These devices are an affordable means of measuring both compressive and tensile forces by the internal strain gauges built into them.

An S-type load cell used for thrust measurements in the static fire equipment

Caution was taken to keep the motor clean during handling and installation by caps on the ports and closing off the nozzle with aluminum foil.

View of Richard’s 1000-lbf motor from below; aluminum foil covering the nozzle exit to prevent foreign object debris (FOD) in the injector

With the validation testing complete and all valves are working, fuel was loaded, then preparations to load the cryogenic liquid oxygen (photo courtesy of Rick Maschek of FAR)

Careful review of the firing procedure before getting down to testing

Preparing for LOX transfer (photo courtesy of Rick Maschek of FAR)

All propellants loaded, everyone in the blockhouse, running the final checks before starting the countdown (photo courtesy of Rick Maschek of FAR)

The view from the blockhouse, a nice clean start of the liquid motor (photo courtesy of Rick Maschek of FAR)

Another view of the rocket firing from Richard’s tripod-mounted camera, 2018-08-18

A few seconds later with the dust kicking up from the motor firing, 2018-08-18

Closeup view of the rocket firing from a small mounted camera; it blew over from the firing but capture this image

Most of the testing seemed to work well. The motor had a clean start and stable run time for the full 5 seconds duration that Richard had predicted. Post-test inspection showed the engine to be in very good condition.

A view from up the nozzle after hot-fire; all looks good

Surface of the 1-inch thick steel plate was melted from the impinging plume; perhaps we’ll mount the next engine a bit higher

Tank pressure measurements were able to be recorded, however the thrust and chamber pressure (Pc) measurements were corrupted. Richard is working on downloading the hot-fire video to be posted on the RRS YouTube channel.

Soon he’ll disassemble the injector and chamber to see if the motor can be fired again. This was a great success for the RRS and we hope this to be the start of several liquid motor hot-fire tests as the RRS continues to improve on this powerful type of rocket.

Richard Garcia stands next to his 1000-lbf kerosene-LOX liquid rocket motor at the RRS MTA, 2018-08-18

I hope that Richard will be able to present his results at the next RRS monthly meeting on the 2nd Friday of the month. The next RRS meeting will be Friday, September 14, 2018 at the Ken Nakaoka Community Center in Gardena, California.

The RRS would also like to thank Mark Holthaus and Rick Maschek of FAR for their assistance on this test.

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Lawn Atlas Missile Base tour

From the ancient armies of China and India and the 19th century British armies using solid rockets in combat, to Von Braun’s work in Nazi Germany and Robert Goddard’s work with the U.S. Navy during the Second World War, the history of rocketry can not be told without mentioning the military aspects of these powerful devices. Modern rocketry at the dawn of the Space Age has roots in one of the most lethal weapons in mankind’s history.

A few years back (June 2014), my wife and I arranged a tour of an unusual piece of Cold War history in the middle of Texas. Larry Sanders, our gracious host is the owner of a former nuclear missile site just outside of the small town of Lawn, Texas. Through his hard work, he has begun to restore his own Cold War museum at this lonely piece of land adjacent to the rolling Texas plains and pastureland.

Longhorn steer grazes on the Texas prairie next to the Lawn Atlas Missile Base

This area, now called the Lawn Atlas Missile Base (LAMB) was once a first-generation Inter-Continental Ballistic Missile (ICBM) site near the small town of Lawn, Texas, less than 20 miles from Abilene, home to Dyess Air Force Base (AFB). Larry gives tours to schools and other interested parties in the local area of central Texas. He’s also been in the local and regional news for his work in restoring his missile silo into a unique historical site for the public.

Lawn Atlas Missile Base from Google Earth satellite imagery

Larry Sanders article – The Eagle

The Atlas ICBM Highway in central Texas (Texas Highway 604, south of Interstate 20)

Larry Sanders gives a tour of the Lawn Atlas Missile Base site outside of Lawn, Texas

In the early days of the Cold War era, the United States and the Soviet Union were in a race to develop launch vehicles to deliver nuclear warheads to the other side of the world from home and friendly territory. The early ICBM’s were liquid fueled rockets based on the higher performance over solid rocket motors of that time. Liquid oxygen (LOX) and kerosene (RP-1) were common high performance propellants in the late 1950’s and early 1960’s (and still commonly used today). The Atlas rocket stood 82.5 feet tall and 10 feet in diameter and with a gross lift-off weight of 268,000 pounds and a total thrust at sea level of 375,000 pounds from all three of its engines could deliver a W38 nuclear warhead over 9000 miles away.

The basic parts of the Atlas F missile

The Atlas rocket designed and built by Convair in San Diego, California, in the 1950’s. The Atlas used a unique vehicle staging concept called “a stage-and-a-half.” Staging of early rocket vehicles at that time was difficult and often plagued with failures. In the 1950’s, there was a concern about reliably igniting the second stage engines in the thin atmosphere at high altitudes. To counter this, the engineers at Convair devised a vehicle that would use a single set of RP-1 and liquid oxygen (LOX) tanks and rapidly ignite all three engines with pyrotechnic cartridges at the same time on the ground. In the middle of ascent, the booster segment would drop away thereby shedding the weight of the two booster engines with their associated pumps in flight. By doing this, the Atlas would finish the mission with only the middle sustainer engine to the end of the flight as the vehicle became lighter.

Rocketdyne MA-3 engine cluster for the Atlas stage-and-a-half rocket

Rocketdyne of Canoga Park, California, built the complex MA-3 engine system for the Atlas ICBM that had two outboard booster engines and a central sustainer engine. The MA-3 engine had a separate turbopump and gas generator for each of the three engines arranged in a line. The MA-3 engine also had two small vernier engines for roll-control, one on opposite sides over the sustainer.

Rocketdyne MA-3 booster engine, LR89-NA-5; two units

Rocketdyne MA-3 sustainer engine, LR105-NA-5; single core engine

Rocketdyne MA-3 vernier engine used on Atlas F vehicle

Atlas booster with the stage-and-a-half concept; outside booster engines fall away leaving the sustainer engine to finish the flight

The Atlas was the first operational ICBM in the American arsenal during the height of the Cold War. Twelve missile bases such as the one near Lawn, Texas, were clustered in around a central strategic command center, a U.S. Airbase in that region. In this case, Dyess Air Force Base in Abilene, Texas, is the former hub of this set of twelve SM-65 Atlas-F type missile sites.

SM-65 Atlas Missile Sites throughout the United States in the 1960’s

Lawn Atlas Missile Base location with respect to Dyess AFB in Abilene, Texas

The Atlas-F type was the last and most advanced version of the SM-65 series. With the RP-1 kerosene fuel loaded and waiting on standby, the Atlas missile was raised vertically from an underground silo to then be tanked with its cryogenic oxidizer (LOX). Air separation plants and special cryogenic liquid handling equipment were required to fuel these first-generation missiles. During its service life, the US Air Force maintained this land-based system to be ready to launch from the surface of the silo within minutes with just a small highly-trained crew.

Atlas-F, SM-65 ICBM in testing

Today, just a few things remain at the surface including the massive, reinforced concrete silo door slab at the Lawn Atlas Missile Base. Two doors are built into the roof where the missile was lowered and raised from its protective silo in the ground.

Lawn Atlas Missile Base – silo and ground access

Atlas-F missile silo as seen from the surface

Top side panaroma of the LAMB site

The Atlas E and F models were the first American ICBM’s to have an on-board computer for guidance using an inertial navigation system. The missile silo had a fixed sighting station to finely calibrate the missile guidance package to make it ready to accurately strike it’s target on the other side of the world. Some parts of this equipment still remain at the site.

The sighting equipment slab facing to the north of the missile silo seen in the background

Atlas ICBM guidance system using an optical sighting apparatus from within the silo

Remnants of communication equipment left at the site

An old antenna mount at the missile site

In the site’s operational period, there were a few small quonset huts at the surface to park servicing equipment for the missile and the silo. Some of the original foundations from these structures still remain at the site as can be seen in the satellite view.

Sketch of the Atlas missile ground support crew and trailers

Atlas F missile base with quonset hut support buildings

Atlas-F perched on the launch table with the blast deflector in place.

Atlas missile stored within its protective silo, erector structure and lifting equipment can be seen

Atlas silo and its underground control room / missile lifted and ready for launch

Our tour started at the protruding angled structure with the surface door angling down below the ground through a convoluted path to the next door.

Atlas F silo – ground access

Ground level door going into the Launch Command Center (LCC) of the Atlas F missile silo; the emergency escape hatch from the LCC can be seen to the right

Down the stair past the first door at ground level

The path from the ground access door leads down two flights of stairs to a couple of turns leading to a pair of entrapment doors. Beyond the entrapment doors are another pair of vault doors. At the LAMB site, a vintage Coke machine is between the two vault doors. Beyond the vault doors leads to a two-floor stair case giving acccess into the round two-floor Launch Control Center (LCC).

entrapment doors in red; the two vault doors in blue

first turn at the bottom of the stairs

the first of two simple doors just around the first corner

The first of two vault doors leading into the stairwell going into the LCC

Vintage (1960’s) Coke machine just behind the first vault door

Vault door latching mechanism

Mechanical vault door actuator from the inside

Once past the radiation-resistant vault door, the two man crew would descend a two-flight set of stairs to access the two-levels of the round LCC. A vintage Coke machine was just behind the door which was a little bit of civilization inside this rugged castle. The whole missile silo was very cool despite the summer heat at the surface, but the humidity inside of the barren silo was very high. Larry said that he very often had to spread desiccant and was frequently combating the mold that would flourish in the moist darkness.

Stairwell access to the Atlas-F LCC

Plate steel stairwell, entering the top floor of the LCC

Bottom of the stairwell, access to the lower deck of the LCC

The Launch Control Center is a two-floor “pillbox” cylinder bunker that housed the crew and the command equipment for operating the missile and the silo equipment. When the site was decommissioned, nearly all of this equipment was removed leaving only the bare walls and only a few non-military items. Having studied the subject and learning what he could from past missileers, our tour guide Larry provided details of where the crew slept, ate and conducted their duties all underground behind the vault door protected from nuclear attack from above.

Identification of equipment and features inside of the LCC

Nearly all of the original wiring and electrical fixtures were stripped out, so Larry has worked to slowly bring back ambient lighting into the LCC, or at least enough to safely conduct tours. Some of my pictures did not turn out so well in the low light, but the LCC had a lot to see.

Launch Control Center (LCC) of the Atlas-F missile silo

top floor inside the LCC in the Atlas-F missile silo

Crew cots around the circumference of the circular LCC (fuzzy from the low light)

Emergency escape hatch from the LCC

Kitchen area inside the LCC, much of this equipment was added (such as the microwave oven)

American eagle emblem hangs just above the kitchen area in the LCC

The lower level had housed the control equipment. Much of this equipment including the electrical fixtures were stripped away. What remains is an old circular photo darkroom and a really nice poster showing the Atlas SM-65 missile.

Picture of the Atlas SM-65 missile next to the circular darkroom for processing camera film

From within the stairwell at the lower level of the LCC, it’s a two-man job, always

Lower level in the LCC

Another view of the lower level of the LCC

The two-story LCC has an access tunnel leading to the missile silo. This circular path had a flat metal grating floor with a corrugated metal piping wall. This access tunnel was heavily corroded from the years of trapped moisture from the missile silo slowly filling with water as the ground water slowly bleeds through the small pores of the concrete. This is a common problem in subterranean structures, like missile silos. My pictures of this access tunnel were difficult to take from the low light conditions even with the camera flash feature.

Circular access tunnel between the LCC and the Atlas missile silo

LCC access tunnel with silo blast doors

Corrugated metal walls of the access tunnel with empty electrical cable trays

A slightly better view of the access tunnel when looking back at the lighted stairwell

A view back at the access tunnel and silo blast doors from the overhanging deck in the missile silo

The missile equipment and silo structures have been stripped out of the silo during decommissioning leaving a dark cavernous cylindrical vault. Larry had a make-shift metal deck installed just at the edge of the opening to the silo, with a rope ladder leading down to a floating platform he set at the waterline.

A look over the edge of the metal deck just past the access tunnel entrance into the missile silo

overhanging metal deck into the missile silo

view looking down into the empty cavernous missile silo; it’s really hard to appreciate just how huge it is inside

Another view of the missile silo interior wall showing the metallic hard point connections for what might have been the missile elevator equipment to bring the rocket to the surface for launch; only the embedded equipment in the walls remain to rust

The two folding doors remain in the down position as the hydraulic piston actuators to open the doors were moved during decommissioning

Over time, rainwater would leak in from the silo doors at the top. Also, groundwater slowly seeps through the concrete filling the silo roughly half full of very clean, very fresh water. Larry is not entirely sure what, if anything, is remaining down at the bottom of the silo. Divers had once expressed interest in exploring the bottom of the silo, but thus far, no one has explored the bottom. My pictures really do not do justice to this impressive site of being within this empty silent tomb.

Looking up at the silo door in the slab from inside of the missile silo

Floating platform within the empty Atlas-F missile silo full of fresh groundwater

After seeing the missile silo, we returned to the LCC to examine some of the posters and documents Larry had collected on the Atlas missile and the missile base.

Collection of photos and Atlas missile silo information

Location of the Lawn missile base in the set of 12 surrounding Dyess AFB in Abilene, Texas

Figurative drawing of the Atlas F missile silo, on display in the LCC

poster of the Pocket Rockets in Texas

As the Atlas was being deployed as weapon, the rocket fulfilled an important early role in the manned spaceflight program. The first Americans in space, Alan Shepard and Gus Grissom, flew on Redstone rockets, but were unable to reach orbit. John Glenn, the first American to orbit the Earth in 1962, did so in his Friendship 7 Mercury capsule fitted on the more powerful Atlas used as a manned spaceflight vehicle.

An Atlas ICBM adapted to launch the Mercury capsule piloted by John Glenn

John Glenn, the first American to orbit the Earth, catching a ride on an Atlas.

Atlas-Mercury 6 launch

Although the Atlas had a fairly short operational history as an ICBM (1961-1966), derivatives of the same Atlas launch vehicle design continued to serve an important role as a space launch vehicle for military, government and commercial payloads. The remaining Atlas F vehicles became space launch vehicles with the last one flying out in 1981. The Atlas F could loft a 820 kg (1800 lbm) payload to a 185 km polar orbit.

Starting with the Atlas G and H vehicles, the Atlas evolved over the decades all the way into the early 2000’s. The last derivative of the original Atlas ICBM was the Atlas 2AS vehicle with a Rocketdyne MA-5A engine cluster that flew its last flight in 2004.

Atlas H launches a payload to space

An Atlas 2AS takes flight

I really recommend visiting the LAMB site as Larry Sanders has really put a lot of his time and resources into gradually recovering the site from the great state of disrepair after being left dormant for decades. He has done a lot of great work in restoring the place and is active in continuing the project. The LAMB tour offers people a rarely seen part of Cold War history. Although, the missile silo is now an empty vault serving as a museum, it’s easy to forget that this site was built to be one of the most lethal weapon systems ever created. Pictures do not really tell the whole story as visiting the site in person can give you the feeling of being inside a place manned by a handful of dedicated servicemen charged with the awesome and haunting responsibility of maintaining a crucial element of the nation’s nuclear deterrent ready for a day that thankfully never came.

Although the Cold War era ended in 1991, land-based strategic nuclear weapons remain in operation in Russia, the United States, China and other countries around the world.

For future reading, there’s a few websites dedicated to the Atlas missile bases from the Cold War. One has the specific details of the Atlas-F, the last and most advanced in the series.

Atlas Missile Silo

Another good place to look at the old missile sites is SiloWorld.net

Siloworld.net

Also, for those interested in the Atlas SM-65 rocket, Wikipedia has a nice summary.

SM-65 Atlas – Wikipedia

Atlas rocket family – Wikipedia

If you’re ever in the Abilene area and interested in a tour of LAMB or just interested in more information on the LAMB site and Atlas ICBM history, readers are encouraged to contact Larry Sanders by his email below:

atlassilo@yahoo.com

I hope you’ve enjoyed this article as this has been a few years, but a very memorable experience. For any questions or comments, contact the RRS secretary.

secretary@rrs.org

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