Explorer 1 and the Van Allen Story

On February 1st, 1958 at 03:48 UTC (January 31st at 22:48 EST), the first Juno booster launched Explorer 1 into Low Earth Orbit. It was the first satellite to be successfully launched by the United States, and the third ever, after Sputnik 1 and 2 in 1957. Launched from the Army Ballistic Missile Agency’s (ABMA) Cape Canaveral Missile Annex in Florida, now known as Launch Complex 26. The launch played a pivotal part in the discovery of the Van Allen Belt, Explorer 1 was the start of the Explorer series, a set of over 80 scientific satellites. Although sometimes looked over in the history of space, it guided the US space program to what it eventually became.

William Hayward Pickering, James Van Allen, and Wernher von Braun display a full-scale model of Explorer 1 at a crowded news conference in Washington, DC after confirmation the satellite was in orbit.

In 1954 The US Navy and US Army had a joint project known as Project Orbiter, aiming to get a satellite into orbit during 1957. It was going to be launched on a Redstone missile, but the Eisenhower administration rejected the idea in 1955 in favour of the Navy’s project Vanguard. Vanguard was an attempt to use a more civilian styled booster, rather than repurposed missiles. It failed fairly spectacularly in 1957 when the Vanguard TV3 exploded on the launchpad on live TV, less than a month after the launch of Sputnik 2. This deepened American public dismay at the space race. This lead to the army getting a shot at being the first american object in space.

The launch
Launch of Jupiter-C/Explorer 1 at Cape Canaveral, Florida on January 31, 1958.

In somewhat of a mad dash to get Explorer 1 ready, the Army Ballistic Missile Agency had been creating reentry vehicles for ballistic missiles, but kept up hope of getting something into orbit. At the same time Physicist James Van Allen of Iowa State University, was making the primary scientific instrument payload for the mission. As well this, JPL director William H. Pickering was providing the satellite itself. Along with Wernher Von Braun, who had the skills to create the launch system. After the Vanguard failure, the JPL-ABMA group was given permission to use a Jupiter-C reentry test vehicle (renamed Juno) and adapt it to launch the satellite. The Jupiter IRBM reentry nose cone had already been flight tested, speeding up the process. It took the team a total of 84 days to modify the rocket and build Explorer 1.

Preparing the explorer 1
Explorer 1 is mated to its booster at LC-26

The satellite itself, designed and built by graduate students at California Institute of Technology’s JPL under the direction of William H. Pickering was the second satellite to carry a mission payload (Sputnik 2 being the first). Shaped much like a rocket itself, it only weighed 13.37kg (30.8lb) of which 8.3kg (18.3lb) was the instrumentation. The instrumentation sat at the front of the satellite, with the rear being a small rocket motor acting as the fourth stage, this section didn’t detach. The data was transmitted to the ground by two antennas of differing types. A 60 milliwatt transmitter fed dipole antenna with two fiberglass slot antennas in the body of the satellite, operating at 108.3MHz, and four flexible whips acting as a turnstile antenna, fed by a 10 milliwatt transmitter operating at 108.00MHz.

Explorer 1 parts
A diagram showing some of the main parts of the Explorer 1 satellite

As there was a limited timeframe, with limited space available, and a requirement for low weight, the instrumentation was designed to be simple, and highly reliable. An Iowa Cosmic Ray instrument was used. It used germanium and silicon transistors in the electronics. 29 transistors were used in the Explorer 1 payload instrumentation, with others being used in the Army’s micrometeorite amplifier.  The power was provided by mercury chemical batteries, what weighed roughly 40% of the total payload weight. The outside of the instrumentation section was sandblasted stainless steel  with white and black stripes. There were many potential colour schemes, which is why there are articles models and photographs showing different configurations. The final scheme was decided by studies of shadow-sunlight intervals based on firing time, trajectory, orbit and inclination. The stripes are often also seen on many of the early Wernher Von Braun Rockets.

NASM flight spare
The flight ready spare of the Explorer 1, now shown at the National Air and Space Museum.

The instrument was meant to have a tape recorder on board, but was not modeled in time to be put onto the spacecraft. This meant that all the data received was real-time and from the on board antennas. Plus as there were no downrange tracking stations, they could only pick up signals while the satellite was over them. This meant that they could not get a recording from the entire earth. It also meant that when the rocket went up, and dipped over the horizon, they had no idea whether it got into orbit. Half an hour after the launch Albert Hibbs, Explorers System designer from JPL, who was responsible for orbit calculations walked into the room and declared there was a 95% chance the satellite was in orbit. In response, the Major snapped: “Don’t give me any of this probability crap, Hibbs. Is the thing up there or not?”.

Explorer 1 Mission Badge
The official JPL mission pac=tch for the Explorer 1 mission.

The instrument was the baby of one of Van Allens graduate students, George Ludwig. When he heard the payload was going into the Explorer 1 (and not the Vanguard) he packed up his family and set off for JPL to work with the engineers there. He has a good oral history section on this link, talking about designing some of the first electronics in space. He was there watching the rocket launch and waiting for results. From the Navy’s Vanguard Microlock receiving station they watched the telemetry that reported the health of the cosmic-ray package. The first 300 seconds were very hopeful, with a quick rise in counting rates followed by a drop to a constant 10-20  counts per second, as expected. The calculations told them when they should hear from the satellite again, but 12 minutes after the expected time, nothing showed up but eventually, after pure silence, Explorer 1 finally reported home.

The Van Allen Belt
This diagram showcases the Van Allen belts, which were first detected by instruments aboard Explorer 1 and Explorer 3. The Van Allen belts were the first major scientific discovery of the space age.

Once in orbit, Explorer 1 transmitted data for 105 days. The satellite was reported to be successful in its first month of operation. From the scientist point of view, the lack of data meant the results were difficult to conclude. The data was also different to the expectations, it was recording less meteoric dust than expected and varying amounts of cosmic radiation, and sometimes silent above 600 miles. This was figured out on Explorer 3 when they realised the counters were being saturated by too much radiation. Leading to the discovery of the Van Allen Radiation Belt. Although they described the belt as “death lurking 70 miles up” it actually deflects high energy particles away from earth, meaning life can be sustained on earth. The satellite batteries powered the high-powered transmitter for 31 days, and after 105 days it sent it’s last transmission on May 23rd 1958. It still remained in orbit for 12 years, reentering the atmosphere over the pacific ocean on March 31st after 58,000 orbits.

When Planes Need an Eye Test

Naval Outlying Field Webster
The photo resolution marker at Naval Outlying Field Webster, From Google Maps

A few years ago, The Center for Land Use Interpretation (CLUI) reported on the dozens of Photo calibration targets found in the USA. They are odd looking two dimensional targets with lots of lines on the of various sizes, used as part of the development of aerial photography. Mostly built in the 1950’s and 60’s as part of the US effort of the cold war.

Shaw Air Force Base
The photo resolution marker at Shaw Air Force Base. From Google Maps

At this point, just after the second world war, there was a huge push to get better information about the enemy. The military needed better aerial recconasance. This very problem lead to the development of the U-2 and the SR-71. As part of this, there needed to be methods of testing these planes with the big camera systems attached to them. This was before the development of digital photography, so resolution is much more difficult to test.

The USAF test target
The 1951 USAF test target from wikipedia, they can still be bought.
Fort Huachuca
The photo resolution marker at Fort Huachuca. From Google Maps

This is where the photo resolution markers came in. Much like an optometrist uses an eye chart, military aerial cameras used these giant markers. Defined in milspec MIL-STD-150A, they are generally 78ft x 53ft concrete or asphalt rectangles, with heavy black and white paint. The bars on it are sometimes called a tri-bar array, but they can come in all forms, such as white circles, squares, and checkered patterns.

Beaufort Marine Corps Base
The photo resolution marker at Beaufort Marine Corps Base. From Google Maps

The largest concentration of resolution targets is in the Mojave desert, around Edwards Air Force Base. This is the place most new planes were tested during this time, with the U-S, SR-71 and X-15 being just some of the planes tested there. There are a set of 15 targets over 20 miles, known as photo resolution road. There are also plenty of other resolution targets at aerial reconnaissance bases across the US, such as Travis AFB, Beaufort Marine Corps Base and Shaw Air Force Base.

Elgin Air Force Base
The photo resolution marker at Elgin Air Force Base. From Google Maps

Semi Autonomous Robotic Platform

As part of my degree I had to complete a project as part of the third year in the field of robotics and electronics. I chose to make a robotic platform, a simple idea that could be completed to a high quality with the right amount of effort. What is a robotic platform I hear you ask? well it essentially is a small buggy/rover that that moves around an assigned area completing simple jobs such as transporting goods, picking up parcels or any job that needs a moving vehicle. Usually autonomous, and very expensive, the majority of systems are very application specific. Some simple systems without any sort of control system can cost tens of thousands of pounds, and are not easy for the average employee to operate. Tackling the problem of expensive, application specific robotic platforms was the basis of my project.

4WD robotic platform
The Nexus 4 wheeled drive mecanum robot has an arduino based control system, and mecanum wheels, but will set you back $1500

Named the Semi Autonomous Robotic Platform, the idea was very simple, make a modular system, with building blocks that could be easily interchanged, and didn’t cost the world. These modules were things like motor controllers, sensors and power systems. If a user had a working platform built from this system, it would take minimal effort to swap out any of these modules to bigger motors or better sensors. This means a user can make a robot and only buy the bits they need, and even make their own modules, as long as they fit to the standard written as part of the project.

system block diagram
The initial block diagram of the system, showing how the modules can be controlled in hierarchy structure.

In most robotic systems, mainly to keep costs cheap, there is one controller that controls everything. This idea makes sense for small integrated systems that don’t need to change, but doesn’t really work when systems need to be dynamic. For instance, say you decide that your DC motors driving your robot aren’t giving you the control you want. You source some stepper motors, but this means completely changing the motor controller and therefore the software that controls it. Because one controller is in charge of everything, the software for the whole system needs to be re-written, and re-tested. That small change could have affected any of the other systems that that controller is in charge of. Make a change that breaks something important, you could set back a project weeks. This shows how painful a setup like this can be, especially when it starts to become a complex robot. Add on top of that the potential for computer intensive algorithms being used on the robot, like route planning or SLAM, and that controller suddenly has a lot to do. My system design separates these jobs out to a selection of individual controllers, such as a system specifically for motor control, or power systems. These controllers can deal with the nitty gritty hardware, and leave the master controller to orchestrate a higher level version of control.

Final Year Project
My design, near the end of the project, with the mecanum wheels, ultrasonic sensors and multiple controllers.

The added benefit of separating out all these jobs means that multiple engineers can work on the same robot, at the same time on different areas and not be worried about breaking the other person’s design. The system specification defines how the modules interact in terms of communication speeds/type, the way to alert other modules and how those communications are scheduled. The master controller (shown in the system block diagram in green) schedules all these communications and decides which modules need specific information. Warnings, control signals and user inputs are all calculated and scheduled, then communicated to and from the required modules. A power system doesn’t care that a user has pressed a button to scroll through an LCD screen, and the master controller means it doesn’t see it.

The above video shows how the robot moves with its mecanum wheels, and how it can easy move around environments. I will explain the more technical parts of the project in a later post, but this simple idea became a very heavy hardware based project, rather than the software project it started as. I learnt about mechanical design, PCB design and good techniques associated with electronic design. For these reasons, the robot won the “Best Project” award for 2017. Thank you to: Cubik Innovation for help with electronic design, and providing PCBs, VEX Robotics for donating the wheels, and Altium Designer for providing their electronic design software. I would not have been able to produce the robot I did without them.

Arianespace Launches a Successful Soyuz

VS18 liftoff
VS18 taking off from the Soyuz Launch Complex (ELS) near Sinnamary.

At 17:10 UTC on the 9th of March 2018, Arianespace launched its second rocket of the year from Guiana Space Center at Kourou. Designated VS18, the Soyuz rocket launched four O3b Satellites into orbit more than 3 years after the last O3b launch. Controlled by a Russian ground crew from the Soyuz Launch Complex (ELS) near Sinnamary, there was a 33 minute delay to the start because of bad weather. The Soyuz used was a Soyuz 2-1b/Fregat placing the satellite in Medium Earth Orbit (MEO).

The VS18 launch from Instagram
The VS18 launch from the Instagram of Arianespace.

A somewhat complex launch, the first ascent lasted 9 minutes and 23 seconds placing the launcher in a sub orbital trajectory. After separation the Fregat performed a 4 minute burn to reach 160 x 205 km x 5.16 deg parking orbit. Coasting for 8 minutes, the Fregat performed its second burn for 8 minutes and 36 seconds to enter  a 190 x 7,869 km x 3.88 deg transfer orbit. Then after a coast of 1 hour and 21 minutes to the apogee, the Fregat fired for its third and final time for 5 minutes and 6 seconds, to enter its 7,830 km x 0.04 deg insertion orbit.

Poster of VS18 launch
Poster advertising the VS18 launch from the Arianespace website.

After the third burn, the satellites were release two at a time, with opposite satellites released at the same time. The first were released 2 hours into launch, and the second set 22 minutes later after a short firing of the Altitude Control System. The rocket then performed 2 more burns to lower its orbit to 200 km below the O3b release point. This was a disposable orbit, intended so that it will not interfere with working satellites.

The four 700kg satellites
The four 700kg satellites being lowered being loaded into the fairing, before the launch. Image from Arianespace website.
The O3b Satellites being prepared to be transported
One of the O3b Satellites being prepared to be transported to the launch site.

The Ka band satellites are the fourth set of O3b to be sent up, making the total constellation 16. Arianespace intend to launch the next set of four in 2019. “The new Ka-band satellites will join the existing O3b constellation to deliver high-speed connectivity to people and businesses in the growing mobility, fixed data and government markets,” Arianespace officials said in a statement. It was reported that the launch was a success, and the Luxembourg based satellite operator SES Networks now have control of the O3b’s.

The fairing of VS18 ready to launch
The fairing of VS18, ready to be attached to the Soyuz rocket, picture from Arianespace website.

The second launch of the year, Arianespace delayed the launch from the original March 6th launch date. This was postponed to conduct extra checks, likely inspired by the partial failure of the Ariane V earlier this year. On January 25th the company lost contact with the upper stage of the rocket. The 3 satellites on board did reach orbit despite the anomaly, but Arianespace have been quiet on the condition of them.

Launch of VS18 with four Ob3
Launch of VS18 with four Ob3 satellites on board. Image from Arianespace website.

How Going To The Moon Kick-started the Silicon Age

In the late 1950’s, there were three people who were at the epicenter of a huge breakthrough in the world of electronics, the invention of the Integrated Circuit (IC). Jack Kilby of Texas Instruments, Kurt Lehovec of Sprague Electric Company, and Robert Noyce of Fairchild Semiconductor. In August 1959, Fairchild Semiconductor Director of R&D, Robert Noyce asked Jay Last to begin development on the first Integrated Circuit. They developed a flip-flop with four transistors and five resistors using a modified Direct Coupled Transistor Logic. Named the type “F” Flip-Flop, the die was etched to fit into a round TO-18 packaged, previously used for transistors. Under the name Micrologic, the “F” type was announced to the public in March 1961 via a press conference in New York and a photograph in LIFE magazine. Then in October, 5 new circuits were released, the type “G” gate function, a half adder, and a half shift register.

The Type F flip flop
Junction-isolated version of the type “F” flip-flop. The die were etched to fit into a round TO-18 transistor package
Type F life image
Physically-isolated Micrologic flip-flop compared to a dime from LIFE magazine March 10, 1961

These first few integrated circuits were relatively slow, and only replaced a handful of components, while being sold for many times the price of a discrete transistor. The only applications that could afford the high prices were Aerospace and Military systems. The low power consumption and small size outweighed the price drawbacks, and allowed for new and more complex designs. In 1961, Jack Kilby’s colleague Harvey Craygon built a “molecular electronic computer” as a demonstration for the US Air Force to show that 587 Texas Instruments IC’s could replace 8,500 discrete components (like transistors and resistors) that performed the same function. In 1961, the most significant use of Fairchild Micrologic devices were in the Apollo Guidance Computer (AGC). It was designed by MIT and used 4,000 type “G” three input NOR gates. Over the Apollo project, over 200,000 units were purchased by NASA. The very early versions were $1000 each ($8000 today) but over the years prices fell to $20-$30 each. The AGC was the largest single user of IC’s through 1965.

apollo guidance computer logic module
Apollo logic module assembled by Raytheon to be used in the AGC
Type G micrologic
Philco Ford also produced the Fairchild Type ‘G’ Micrologic gate for the Apollo Guidance Computer – this is the flat pack verison

Note that although Fairchild designed and owned the type “G” device, they were mostly made by Raytheon and Philco Ford under licence from Fairchild. Over this time many semiconductor manufacturers such as Texas Instruments, Raytheon and Philco Ford were also making large scale silicon production for other military equipment. These included the LGM-30 Minuteman ballistic missiles, and a series of chips for space satellites. This major investment from the government and the military kick started the development of the increasingly complex semiconductor, and eventually forced the prices low enough for non military applications. The processes improved and by the end of the Apollo program, hundreds of transistors could be fitted into an IC, and more complex circuits were being made. Eventually the costs of adding more transistors to a circuit got extremely low, with the difficulty being the quality of manufacturing. It could be argued that NASA and the Pentagon paved the way for silicon device production as we know it today.

The 50th Flight of the Falcon 9

Awe inspiring Falcon 9 Photo
A truly awe inspiring photo Of the Falcon 9’s 50th flight. From the SpaceX Flickr.

At 05:33 UTC on March 6th 2018 SpaceX launched it’s 50th Falcon 9 mission. The version 1.2 Falcon 9, with a brand new “Block 4” variant booster B1044, lifted off from Cape Canaveral Space Launch Complex 40. On board, inside the type 1 fairing was Spain’s Hispasat 30W-6. Weighing in at 6,092kg, being the size of a bus and being launched into geosynchronous transfer orbit, it’s the biggest challenge that the Falcon 9 has come up against.

50th Falcon 9 Flight 1
50th Falcon 9 flight soars into the Florida night sky, Image by @marcuscotephoto on Twitter

The First stage if the Falcon 9 fired for about 2 minutes and 35 seconds before releasing and plummeting back towards the Atlantic ocean. The initial plan was top land the “type 4” first stage on the autonomous drone ship “Of Course I Still Love you” in the Atlantic. Landing legs and titanium steering grid fins were attached and went up with the rocket.  There was already speculation, due to the large payload and the orbit attempted, whether the Falcon 9 would have enough fuel left to attempt the reentry and landing procedure. Unfortunately it was not possible to find out whether the F9-51 mission would have made a landing because the autonomous drone ship was kept in port because of high sea conditions. The rocket still went through the entire reentry and landing procedure, as mentioned on the livestream, but ended up in the Atlantic.

Long exposure of Falcon 9
An awesome long exposure shot of the Falcon 9 Taking off from SLC-40. From @marcuscotephoto on Twitter

almost 9 minutes in, the second stage with the payload achieved a Low Earth Orbit, and “parked” until T+26 min 36s where they first crossed the equator. This second burn lasted 55 seconds to accelerate the ss/Loral-built satellite  into a Geosynchronous Transfer Orbit. The Hispasat 30W-6 will fire its four SPT-100 plasma thrusters to gradually raise itself to Geosynchronous Orbit positioned 30 degrees West (clue in the name). Hispasat 30W-6 is designed to provide broadband services in Europe and Northwest Africa.

The Hispasat 30W-6 launching
The Hispasat 30W-6 launching at night, from SLC-39. From SpaceX Flickr.
Timelapse of Falcon Launch
Timelapse of Falcon Launch from across the water, from SpaceX Flickr

This is the fourth all-expendable Falcon 9 launch in the past 5 years, and the first time a “type 4” stage has been expended on it’s first flight. Both of the stages of the F9-51 rocket were tested at SpaceX Rocket Test Facility in McGregor, TX during October/November 2017. They have been at Cape Canaveral since January 2018, and were stacked ,loaded with propellant and tested (first stage only) at the Cape at SLC 40 on February 20, 2018. The Launch was initially planned for February 25th, but was shelved by SpaceX to investigate payload fairing pressurisation issues.

Raw power of Falcon 9
An image showing the raw power of the Falcon 9, from SpaceX Flickr.

The Latest Atlas V Launch GOES-S Well

The Atlas V launch
The Atlas V launch taken by @marcuscotephoto on twitter.

At 22:02 UTC on March 1st 2018 the Second Atlas V launch of 2018 fired the 5,192kg GOES-S satellite into orbit. Launching from Space Launch Complex 41 at Cape Canaveral, FL, the AV-077 (the launch designation) was an Atlas V in 541  configuration. GOES-S, an A2100 series satellite built by Lockheed Martin, was separated 3.5 hours into the mission into a 8,215km x 35,286km x 9.52 deg Geosynchronous Transfer Orbit (GTO).

Atlas V launch
Atlas V launch from Launch Complex 41 at Cape Canaveral, FL. Image from @NOAASatellites Twitter.

The second of a new generation of weather satellites for the United States, GOES-S follows in the footsteps of GOES-East, now renamed to GOES-16. A huge jump in satellite capability, the new set of satellites cover from eastern Japan all the way over to west Africa, as well as parts of the Arctic and Antarctic. They can detect storms faster, see lightning and even have sensors to detect solar storms. The satellites were commissioned by the National Environmental Satellite, Data and Information Service (NESDIS) who manage the National Oceanographic and Atmospheric Administration (NOAA) constellation of environmental satellites. For more images and information follow them on twitter @NOAASatellites.

The new generation of weather satellites
Image showing the difference between GOES-16 and the previous version, GOES-13. Image from @NOASatellites twitter.

There are versions of the livestream on Youtube, and a highlight reel on the ULA Youtube page. They are definitely worth a watch if you want more information from the engineers themselves.

Atlas V launch
Atlas V launching the GOES-S satellite on March 1st 2018. Image from @NOAASatellites Twitter
The Atlas V just taking off
The Atlas V just taking off, Image from @NOAASatellites

To find similar photos, and to buy reasonably priced prints of some of the above visit www.marcuscotephotography.com

The Ups And Downs Of The Falcon Heavy Launch

At 20:45 UTC on the 6th of February 2018 the long awaited Falcon Heavy soared up into the sky. Watching the livestream, there was something slightly different. Instead of the usual single commentator, they had four. Behind them, hundreds of SpaceX employees cheering all the way through the launch, with bigger cheers at each milestone. It was definitely long anticipated, and I even felt the impact at university. Students were going round making sure people knew that tonight was the night that the Falcon Heavy was launching. The stream didn’t disappoint space lovers, and I highly recommend watching it on the SpaceX Youtube page.

So what actually happened,  why was this flight so important? The demo mission was the  first firing of the full Falcon Heavy configuration. Although all the rockets had been previously fired and tested at SpaceX’s rocket test facility in McGregor, TX. Consisting of “Block 2” variant side boosters (B1023.2 and B1025.2) and a “Block 3” variant core stage (B1033.1). Both the boosters had been flown before and refurbished in Hawthorne, CA. B1023.2 was flown May 27th, 2016 for Thaicom 8 launch, landing on SpaceX’s autonomous drone ship “Of Course I Still Love You”. B1025.2 flew on July 18th, 2016 for the CRS-9 mission, landing at Landing Zone (now landing zone 1). It is noted that future Falcon Heavies will likely use the “Block 5” variant. Elon Musk Claims that the development of the Falcon Heavy project has cost $500 million to get to this stage.

Falcon Heavy Before Launch
The Falcon Heavy the night before launch. From @SpaceX on Twitter

At 20:45 UTC, the Falcon Heavy lifted off of pad 39A at Kennedy Space Centre. It weighed roughly 1,400 tonnes and was 70m tall. with 2,128 pounds of thrust, the triple barreled rocket lifted off the pad with its 27 Merlin 1D engines (9 on each booster). At the time of writing it is the largest and most powerful operational rocket in use today by a factor of 2. Elon Musk gave the launch a 50-50 chance of success, but it continued through almost all of the milestones. Through Max-Q, release of boosters, and release of the main engine. The second stage performed 3 burns during the 6 hour mission to accelerate the cargo to into a heliocentric orbit. The orbit ranges from earth orbit to beyond mars (0.99 x 1.71AU). The concept of this burn was to demonstrate long coasts between the second and third burns. This ability is needed for some DoD EELV Heavy class missions, a market that SpaceX wants to compete in.

Falcon Heavy Launching
Falcon Heavy launching from pad 39A at Cape Canaveral Air Force Base.
Intended Orbit
Intended orbit of the Falcon Heavy payload, heliocentric. From Elon Musk’s Twitter.

Usually on these types of initial flights they put some sort of simulated weight in the fairing (the bit that holds the payload on top) usually a block of concrete. Elon Musk being Elon saw this as a marketing opportunity, and instead used his personal 2008 cherry red Roadster, weighing in at 1,250kg. In the driver’s seat sat a full scale human mannequin named “Starman”, wearing a SpaceX branded pressure spacesuit. The person who timed the release of the fairing showing the Tesla against the backdrop of the earth, to the music of “Life of Mars” by David Bowie, deserves a medal. Although perfectly timed, it is sometimes incorrectly attributed as “Starman” by Bowie, which would make more sense when you think about it. On the dashboard of the car is the immortal words of “don’t panic”, a tribute to A Hitchhiker’s Guide to the Galaxy, that was a clever addition. There is a livestream of the first 5 hours of Starmans trip, at which time it probably lost signal, or ran out of battery. There has been mixed reviews of this stunt. Some call it art, whereas others call it “space littering”. Some commentators such as Burnie Burns on the Roosterteeth Podcast simply don’t like the use of space for marketing purposes. Scientists at Purdue University called it “the dirtiest man-made object ever to be sent to space” due to its use driving in Los Angeles.

Tesla Roadster in Orbit
Elon Musk’s Tesla Roadster with Starman sat in the driver’s seat.

For me personally the most impressive part of the entire video was near to the end. SpaceX have had some famous problems with the landing of their reusable rockets, but during this mission they planned to land all three. The best shot of the entire livestream was the two boosters coming down at the same time, with the Cape in shot. Both boosters opening their landing legs, and coming down to land on Landing Zone 1 and 2. It was a truly epic sight, and from an engineers point of view, very impressive. The second pad was installed for these Falcon Heavy missions, and the boosters worked just as planned. The core was a slightly different story. It attempted to land on the autonomous drone ship “Of Course I Still Love You”. It completed its boost-back and reentry burn, but for the three-engine landing burn, two engines failed to ignite. The core ended up in the Atlantic. Smoothly brushed over, this was not mentioned on the Livestream, and not until a few hours later on Twitter. Even so, the things that did land correctly were impressive.

FH Side Booster Landing
The impressive shot of the side boosters landing simultaneously on LZ1 and LZ2, at Cape Canaveral.

There has been a huge amount of excitement and skepticism about the Falcon Heavy. Some have heralded it the way Elon Musk wants to get to Mars, others just love the idea that the car will be out there for “billions of years”. Although very impressive, the Falcon heavy is really designed to be a beefier version of the Falcon 9, and will probably do the same job. SpaceX are aiming in the coming years to get more contracts from the Department of Defence, and aim to get more up into space at the same time. The Falcon Heavy is all about making it cheaper for big payloads to get to space. Although it has the capability to get to Mars, and carry people, Musk has said that there are bigger plans in the pipeline for those jobs. As for the car, according to chemist William Carroll, solar and cosmic radiation will break down most of the car within a year, leaving just the aluminium frame and maybe some glass that isn’t shattered by meteorites.

The Falcon Heavy Launching
The Falcon Heavy launching, taken from behind a SpaceX hangar near the launch site.

This is a big moment for SpaceX, and the space community, and shows that there are big things coming in the sector. There are big launches aimed from the big companies this year, and new rockets being unveiled in the near future. SpaceX may have just started a new space race. For all the excessive marketing that Elon Musk does, SpaceX have definitely got their marketing message right.

To find similar photos, and to buy reasonably priced prints of some of the above visit www.marcuscotephotography.com

The Foundry: Blowing Smoke

In the last post, we saw a fire actually burning in the foundry. The concrete has set, and doesn’t fall apart while being used. After researching other designs, and using some logic, we figured we need to force more air into the system. As we designed previously, there is a large 30mm hole on the side of the forge to allow air into the fire. Unfortunately, this doesn’t seem to provide the amount of air we need to get the desired heat. We have tried a number of ways to force air into the hole, with varying success. First we literally blew into it, like you would a campfire, and it works well, but soon you start to really hyperventilate, and it’s not good. The next idea was to take a chopping board (but any board will do) and flapped it, forcing air towards the hole. This worked much better than simply blowing. Lots of air fuels the fire, and it burns really hot. The big downside is that it wastes most of the air produced, and creates some interesting smoke patterns that seem to be inefficient. Either way, it is a good cheap way to improve the forge performance.

First Tests
The foundry during its first fire, not particularly hot.

The method we eventually used to force air into the system was in the form of a fan. Before I start this section, it comes with a warning, you need to wear goggles if you try this, as will be explained. You have been warned. The initial fan was in the form of an old hairdryer, bought from a charity shop for £3. Putting it right up to the hole forced hot air directly into the hole, with very little waste air escaping. It worked very well, and the fire started to burn much hotter. It also meant we could control the amount of airflow by using the switches on the hairdryer, or simply moving it further away.

Forcing air into the forge
Forcing air into the forge using a hairdryer, the fire is visibly hotter.

Two issues came up while using this method of airflow. The first big problem is the mass of air being forced into the hole needs to go somewhere. The only place it can go is straight up, and as we don’t have a lid it just fires ash into the air. This is dangerous if gloves and goggles aren’t being worn. This ash can be hot and can take some of that fuel and heat away from the forge. A lid will fix this, and that will be covered in the next post. For this test we kept it at a low fan speed, and found a nice point where we weren’t firing ash into the air, but still giving lots of air to the fire. The second problem was that the hairdryer started getting really hot, and the plastic began to melt. Essentially this means it was too close to the fire, but if you move the fan away then the air just misses. To fix this we found a 30mm diameter iron pipe, and attached the hairdryer to it. This allowed the air to be funneled in with the fan unit being further away from the forge.

The fire burning
The fire burning with a steel tin on top to stop the ash flying out.

So what have we learnt from this fire? We need a lid. This will be a topic of further posts, but for now we know we can produce a hot fire, and the air going into the fire can be controlled. Thanks for reading, and hope to come with another update soon.

Halfpenny Bridge: The Bridge Over Nothing

If you walk down Union street in Plymouth, just before you come to Devonport you will come across what looks like a bridge. Called Stonehouse Bridge, it comes from a time when Plymouth had a very large river/lake separating Devonport and Plymouth-Town. Originally to get across the creek to what was then known as Plymouth-Dock, you had to take the pedestrian ferry, or go all the way up to Mill bridge. So in 1767 Lord Mount Edgcumbe, who was lord of the manor of East Stonehouse, and Sir John Saint Aubyn, Lord of the Manor of Stoke Damerel, obtained an act of Parliament authorising construction of a bridge. The idea was to allow for a more direct link between Plymouth-Dock and East Stonehouse. It made sense when in the Act they described the old ferry as ‘narrow and could only be used by foot passengers’.

Stonehouse Bridge, Plymouth, engraved by W.B. Cooke 1836 Clarkson Frederick Stanfield 1793-1867

The man who designed the Eddystone Lighthouse, that now stands on Plymouth Hoe, John Smeaton, was invited to design the bridge. The bridge charged a toll to get across it, like many bridges of the time, and it was fixed by the act of parliament. It cost 2d return for a 1-horse drawn vehicle, 3d for  a 2 horse vehicle, and 6d for wagons drawn by more than 2 horses. The nickname ‘Halfpenny Bridge’ was from the halfpenny it cost for pedestrians to cross, also it was sometimes pronounced ‘Ha’penny Bridge’. Interestingly it absolved the owners from paying any public or parochial rate or tax.

The old 5 horse car at the halfpenny gate

Opened in 1773, the approach to it was via Stonehouse lane (now known as King Street) and the High Street, rather than Union Street. in 1775 the first carriages began to be hired between Plymouth and Plymouth Dock, over the new bridge. Carriages were popular but Stonehouse lane was described as ‘ruinous’ and a new road was needed. A further Act of Parliament was obtained in 1784 to create the Stonehouse Turnpike Trust. In 1815  Union Street was finally opened, as a turnpike, the users paid a toll to use the bridge, that went to the upkeep of it.  So users now had to pay for the bridge and the road leading up to it. Turnpikes were very popular in the 18th and 19th century and are basically a toll road. In 1828 the bridge was raised while Devonport hill was lowered. This meant that hackney carriages could now be used to provide a route between Plymouth and Devonport the following year.

Stonehouse Bridge from Richmond Walk.

Both Plymouth and Devonport tried many times to purchase the gate, but the bridge, along with Stonehouse Mill bridge were sold in February 1890 to the General Tolls Company Ltd for £122,000. The company (with the Earl of Mount Edgcumbe and Lord Saint Levan had shares in) was registered on February 12th 1980. The idea was for the owners to collect the tolls rather than auction them, which was more common at the time. From October of 1917, servicemen and nurses could get across the bridge for free.

Stonehouse creek before being filled in, from the bridge

After long negotiations, an Act of Parliament in 1923 allowed Plymouth Town Council to buy the toll rights for £100,000. This meant that the Council could have charged tolls and collected than money for up to ten year. Instead, on April 1st 1924, the Mayor, Mr Solomon Stephens, and council visited all the toll houses and declared them free.

Stonehouse Bridge Freeing Ceremony, 1924 looking towards Devonport. From a postcard

The upper end of the creek, near the Pennycomequick, was known towards the end of the 19th century as Deadlake. St Barnabas Terrace, a road now adjacent to the park, was marked on 19th century maps of the area as Deadlake Lane. Toward the end of the 19th century, culverts were made to channel the streams that ran into deadlake, and the swampland was filled in with rubble from the quarries at Oreston and Cattedown. To celebrate queen Victoria’s reign, Victoria Park, along with the park-keeper’s lodge, was formally opened to the public in 1903.

Looking down the filled in fields, towards Stonehouse

Between Mill Bridge and Stonehouse Bridge, the creek was filled in in 1972, when 600,000 tons of ballast and rubble were used to create 19 acres of land. Now a set of pitches for Devonport High School for Boys (previously the royal naval hospital) and the pitch for Devonport RFC. When you walk along it you can see some areas, especially close to the bridge where all the rubble has been added. On the water side of the bridge you can see where the arches have been filled up. Stonehouse bridge is now more of a dam, but one with some important history for Plymouth.

Halfpenny Bridge, on the side of the creek