JAXA Lands Rovers on an Asteroid

An artist’s impression of the Hayabusa 2 probe. Targeting an asteroid, it plans to land, sample it and then return with the sample by 2020.

The Japanese Space Agency have successfully landed and deployed two small rovers onto the surface of a near Earth asteroid from the Hayabusa 2 probe. Following on from its predecessor Hayabusa, this second mission is an asteroid sample return mission, building on and addressing the weak points of the first mission. It launched on the 3rd of December 2014, and it rendezvoused with the near-earth asteroid 162173 Ryugu on the 27th of June 2018. Currently in the process of surveying the asteroid for a year and a half, it will depart in December 2019, returning to Earth in December 2020.

Photo taken by Rover-1B on Sept 21 at ~13:07 JST. It was captured just after separation from the spacecraft. Ryugu’s surface is in the lower right. The misty top left region is due to the reflection of sunlight. 1B seems to rotate slowly after separation, minimising image blur. Credit: JAXA

The Hayabusa probe carries four small rovers that are designed to investigate the asteroid surface in situ. They are designed to provide data and context of the environment around where the returned samples are from. Different from rovers that we are used to, these all use a hopping mechanism to get around. None of the rovers have wheels as there is so little gravity that they would be very inefficient. Deployed at different dates, they are all dropped onto the surface from 60-80 m altitude and fall to the surface by the very weak gravity. The MINERVA-II-1 lander is the container that deployed two of the rovers. ROVER-1A and ROVER-1B were deployed on 21st of September 2018. Developed by JAXA and the University of Aizu, the rovers are identical. They are 18cm in diameter and 7cm tall, with a mass of 1.1kg (2.4lb) each. They hop by using rotational masses within the rover. They have stereo cameras, a wide angle camera, and thermometers aboard. Solar power and a double layer capacitor power them.

First pictures from a MINERVA-II-1 rover that landed on the asteroid. Credit: JAXA.

The  MINERVA-II-2 container holds the ROVER-2, developed by a consortium of universities led by Tokyo University. It is an octagonal prism shape, 15cm diameter and 16cm tall. The mass is about 1kg (2.2lb), and has two cameras, a thermometer and an accelerometer on board. It has optical and UV LED’s for illumination to detect floating dust particles. It has four mechanisms to hop and relocate. The fourth rover, named MASCOT (Mobile Asteroid Surface Scout) was developed by the German Aerospace Center in cooperation with the French Space Agency CNES. It measures 29.5cm x 27.5 cm x 19.5cm and has a mass of 9.6kg (21lb). It carries an infrared spectrometer, a magnetometer, a radiometer and a camera that will image the small-scale structure, distribution and texture of regolith. it is capable of tumbling to re-position itself, and is designed to measure the mineralogical composition, the thermal behavior and magnetic properties of the asteroid. The non-rechargeable battery will only last for 16 hours. The infrared radiometer on the InSight Mars lander, launched in 2018, is based on the MASCOT radiometer.

An artistic rendering of Hyabusa 2 collecting a surface sample.

Thank you for reading, take a look at my other posts if you are interested in space, electronics, or military history. If you are interested, follow me on Twitter to get updates on projects I am currently working on.

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The Dawn of Ion Engines

Ion thrusters are becoming a bigger and bigger part of modern satellite design. Over 100 geosynchronous Earth Orbit communication satellites are being kept in the desired locations in orbit using this revolutionary technology. This post is about its most amazing achievement to date, the Dawn Spacecraft. Just reported that it is at the end of its second extension of the mission it has a few records under its belt. It is the first spacecraft to orbit two different celestial bodies, and the first to orbit any object in the main asteroid belt between Mars and Jupiter. It is also a record breaker for electric speed. Travelling over 25,700 mph it is 2.7x faster than the previous fastest electric thrusted spacecraft. That is a comparable speed to the Delta 2 launch vehicle that got it to space in the first place.

Delta 2 launch
The Dawn spacecraft launching on a Delta 2 rocket from Cape Canaveral Air Force Station SLC 17 on Sept 27th, 2007. Credit: NASA/Tony Gray & Robert Murra

The Dawn mission was designed to study two large bodies in the main asteroid belt. This is to get a deeper insight into the formation of the solar system . It also has the added benefit of testing the ion drive in deep space for much longer than previous spacecraft. Ceres and Vesta are the two most massive bodies in the belt, and are also very useful protoplanets from a scientific standpoint. Ceres is an icy and cold dwarf planet whereas Vesta is a rocky and dry asteroid. Understanding these bodies can bridge the understanding of how the rocky planets and icy bodies of the solar system form. It could also show how some of the rocky planets can hold water/ice. In 2006 the International Astronomical Union (IAU) changed the definition of what a planet is, and introduced the term “dwarf planet”. This is the change that downgraded Pluto from its planet status, although that has been argued to be wrong by Dr. Phil Metzger in a recent paper. Ceres is classified as a dwarf planet. As Dawn arrived at Ceres a few months before New Horizons reached Pluto, Dawn was the first to study a dwarf planet.

Dawn prior to encapsulation at its launch pad on July 1, 2007. Credit: NASA/Amanda Diller

The ion engine is so efficient that without them a trip to just Vesta would need 10 times more propellant, a much larger spacecraft, and therefore a much larger launch vehicle (making it much more expensive). The ion propulsion system that it uses was first proven by Deep Space Mission 1, along with 11 other technologies. Dawn has three 30 cm diameter (12 inch) ion thrust units. They can move in two axis to allow for migration of the center of mass as the mission progresses. The attitude control system can also use the movable ion thrusters to control the attitude. The mission only needs two of the thrusters to complete the mission, the third being a spare. All three have been used at some point during the mission, one at a time. As of September 7th 2018 the spacecraft has spent 5.9 years with the ion thrusters on, which is about 54% of its total time in space. The thrust to its first orbit took 979 days, with the entire mission being over 2000 days. Deep Space 1’s mission in contrast lasted 678 days before the fuel ran out.

An artist’s impression of Dawn with its ion thrusters on. Credit: NASA

The thrusters work by using electrical charge to accelerate ions from xenon fuel to speeds 7-10 times that of chemical engines. The power level and the fuel feed can be adjusted to act like a throttle. The thruster is very thrifty with its fuel, using a minor 3.25 milligrams of xenon per second, roughly 280g per day, at maximum thrust. The spacecraft carried 425 kg (937 pounds) of xenon propellant at launch. Xenon is a great fuel source because it is chemically inert, easily stored in compact form. Plus the atoms are very heavy so they provide large thrust compared to other comparable candidate propellants. At launch on Earth the xenon was 1.5 times the density of water. At full thrust the ion engines produce a thrust of 91 mN, which is roughly the force needed to hold a small sheet of paper. Over time these minute forces add up and over the course of years can produce very large speeds. The electrical power is produced by two 8.3 m (27 ft) x 2.3 m (7.7 ft) solar arrays. Each 18 meter squared (25 yard squared) array is covered in 5,740 individual photo voltaic cells. They can convert 28% of the sun’s energy into useful electricity. If these panels were on Earth they would produce 10 kW of energy. Each of the panels are on gimbals that mean they can turn any time to face the sun. The spacecraft uses a nickel-hydrogen battery to charge up and power during dark points in the mission.

The dawn mission patch.  This logo represents the mission of the Dawn spacecraft. During its nearly decade-long mission, Dawn will study the asteroid Vesta and dwarf planet Ceres Credit: NASA.

Vesta was discovered on March 29th 1807 by astronomer Heinrich Wilhelm Olbers, and is named after the Roman virgin goddess of home and hearth. The Dawn mission uncovered many unique surface features of the protoplanet ,twice the area of California, that have intrigued scientists. Two colossal impact craters were found in the southern hemisphere, the 500 km (310 miles) wide Rheasilvia basin, and the older 400 km (250 miles) wide Veneneia crater. The combined view of these craters was apparent even to the Hubble telescope. Dawn showed that the Rheasilvia crater’s width is 95% of the width of Vesta (it’s not perfectly spherical) and is roughly 19 km (12 miles) deep. The central peak of the crater rises to 19-25 km (12-16 miles) high, and being more that 160 km (100 miles) wide, it competes with Mars’ Olympus Mons as the largest mountain in the solar system. The debris that was propelled away from Vesta during the impacts made up 1% of its mass, and is now beginning its journey through the solar system. These are known as Vestoids, ranging from sand and gravel all the way up to boulders and smaller asteroids. About 6% of all meteorites that land on Earth are a result of this impact.


The brave new world of 4 Vesta, courtesy of NASA’s Dawn spacecraft. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

Dawn mapped Vesta’s geology, composition, cratering record and more during its orbit. It also managed to determine the inner structure by measuring its gravitational field. The measurements were consistent with the presence of an iron core of around 225 km (140 miles), in agreement with the size predicted by
howardite-eucrite-diogenite (HED)-based differentiation models. The Dawn mission confirmed that Vesta is the parent body of the HED meteorites, by matching them with lab based measurements. These experiments measured the elemental composition of Vesta’s surface and its specific mineralogy. These results confirm that Vesta experienced pervasive, maybe even global melting, implying that differentiation may be a common history for large planetesimals that condensed before short-lived heat-producing radioactive elements decayed away. The pitted terrains and gullies were found in several young craters. This could be interpreted as evidence of volatile releases and transient water flow. Vesta’s composition is volatile-depleted, so these hydrated materials are likely exogenic (formed on the surface).

A colour coded topographic map from the Dawn mission of the giant asteroid Vesta. Credit: NASA/JPL

The first object ever discovered in the main asteroid belt was Ceres. Named after the Roman goddess of corn and harvest, it was discovered by Italian astronomer Father Giuseppe Piazzi in 1801. Initially classified as a planet, it was later classified as an asteroid as more objects were found in the same region. In recognition of its planet like properties (being very spherical) it was designated a dwarf planet in 2006 along with Pluto and Eris. Observed by the Hubble telescope between 2003 and 2004, it was shown to be nearly spherical, and approximately 940 km (585 miles) wide. Ceres makes up 35% of the mass of the main asteroid belt. Before Dawn there were plenty of signs of water on Ceres. First, its low density indicates that it is 25% ice by mass, which makes it the most water rich body in the inner solar system after Earth (in absolute amount of water). Also, using Hershel in 2012 and 2013, evidence of water vapor, probably produced by ice near the surface transforming from solid to gas (known as sublimating).

Dwarf planet Ceres is shown in these false-color renderings, which highlight differences in surface materials. Credit: NASA/JPL-CalTech/UCLA/MPS/DLR/IDA

Acquiring all the data it needed by the middle of 2016, Dawn measured its global shape, mean density, surface morphology, mineralogy, elemental composition, regional gravity and topography at exceeded resolutions. The imaging from the mission showed a heavily cratered surface with bright features. Often referred to as “bright spots” they are deposits of carbonates and other salts. Multiple measurements showed an abundance of ice at higher latitudes. However the retention of craters up to 275 km (170 miles) in diameter argue for a strong crust, with lots of hydrated salts, rocks and clathrates (molecules trapped in a cage of water molecules). Gravity and topography data also indicated that that Ceres’ internal density increases with depth. This is evidence for internal differentiation resulting from the separation of the dense rock from the low density water-rich phases in Ceres history. The rock settled to form an inner mantle overlain with a water-rich crust. This internal differentiation is typical of small planets like Ceres and Vesta that Sets them apart from asteroids.

Thank you for reading, take a look at my other posts if you are interested in space, electronics, or military history. If you are interested, follow me on Twitter to get updates on projects I am currently working on.

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The Items Apollo 11 Left behind on the Moon

Aldrin Looks Back at Tranquility Base
Buzz Aldrin Looks Back at Tranquility Base just after deploying the Early Apollo Scientific Experiments Package (EASEP). Credit: NASA.

July 21st 1969. The time is 2:56 UTC, Neil Armstrong is taking the first steps on the moon, 20 minutes later Buzz Aldrin is following. The landing site looks clean apart from the big lander that is their lift home. By the end of the two hour EVA on the lunar surface the site would be walked over, science experiments laid out, and a pile of rubbish left in a pit. A view you don’t get to see in the images from Apollo 11, the astronauts left over 100 items on the lunar surface. Some commemorative, but mostly items they didn’t need for the return journey.

The plaque
The plaque attached to the lunar lander, with a message from all mankind, just in case some other being finds it. It commemorates the first steps on the Moon. Credit: NASA.

Famously landing in the sea of tranquillity, the Eagle lander has a number of official commemorative items attached to it. The main one is a plaque proclaiming “Here men from planet Earth first set foot upon the Moon. July 1969, A.D. We came in peace for all mankind.” Under the “we come in peace” is a golden replica of an olive branch. Nearby is a small aluminium capsule with a tiny Silicon disc inside. It contained on it messages from four US presidents, and seventy three other heads of state. It was sketched onto it in microscopic lettering, with the wording found here. There are also a few non official items taken there by the astronauts. An Apollo 1 patch in memory of Roger Chaffee, Gus Grissom, and Ed White who died in January 1967 in a fire inside the first Apollo capsule. They also left behind two military medals that belonged to Yuri Gagarin and Vladimir Komarov, both famous USSR cosmonauts. It showed the respect these men had for Soviet cosmonauts who had achieved so many firsts, and went through the same trials and tests they did.

The Apollo 1 patch
The patch for the famous Apollo 1 where Roger Chaffee, Gus Grissom, and Ed White tragically died in a fire. The patch was left on the Moon. Credit: NASA

On top of this they left the science experiments that they had used, such as the passive seismic experiment. The experiment that used meteorite impacts on the surface to map the inside structure of the Moon. They also placed a master reflector so that scientists could measure the distance from Earth precisely. This retroreflector still works, and if you have access to a powerful enough laser you can measure it yourself. They also had to pick up lots of moon rocks and moon dust as part of the science mission. They used sample scoops, scales and even a small hammer. There are also many specific tools that were needed, but were discarded before the return journey.

Map of Tranquillity base
Map of Tranquillity base including the Toss Zone where all the rubbish was discarded. Credit: NASA

Overall they left roughly 106 random bits if rubbish at the launch site. Including lots of tools like the hammers, chisel and brushes needed for sampling; astronaut EVA gear such as the over boots and and life support systems; and actual rubbish like the empty food bags, some armrests they wanted to dispose of; a TV camera; insulation blanket; pins and plastic covers for items like the flag (and the flag itself) plus the urine, defecation and sickness bags, although there is no word on whether they were used. They threw all the items into an area behind the lander known as the “Toss Zone”, basically just a rubbish pit.

Buzz with science
Buzz carrying science experiments to the required place slightly away from tranquility base. Credit: NASA

The astronauts left a surprisingly large amount of stuff on the Moon, but it does make sense, as they needed that weight to be replaced with the 300 kg of Moon rocks that they wanted to bring back, so they just left it all there. There is a full list of the items on this webpage, and its worth a look. Archived by the Lunar Legacy Project, they count it as over 106 items. Depending on how you count it, there can be over 116 items left by the Apollo Astronauts.

Thank you for reading, take a look at my other posts if you are interested in space, electronics, or military history. If you are interested, follow me on Twitter to get updates on projects I am currently working on.


The Secret Side of Sleepy North Devon and Cornwall

Barrel Rock Bude
Barrel Rock at the end of the Breakwater on Bude beach, used to guide ships into the harbour.

North Devon and Cornwall, a sleepy area that is full of history of its fishing and farming past. Now with a bustling influx of tourists every summer to enjoy the museums, adventure parks and sunny beaches. Just getting back from a holiday there in Appledore It has all these things, but the one big thing I noticed was the large presence of military sites in the area. Just visible from Appledore is RMB Chivenor, a big marine base, as well as a Babcock site that has built military ships for over 160 years. Just down the road is a selection of old RAF radar stations and airfields, one of which is now a top secret GCHQ site that could be listening to a large portion of the world’s internet traffic.

View From Bude
A view of one of the satellite dishes at GCHQ Bude taken from Bude beach. Credit: me.

On a day trip to Bude in Cornwall, after the customary ice cream we took a walk down the beach and were drawn to the Breakwater. More specifically a big rocky section at the end of the breakwater called Barrell Rock. Named so because of the barrel on the end of a long pole used to guide ships around the dangerous rocky breakwater. It gave a great view of the beach and bude itself,  and the chapel said to be where Bude originated. One thing I did notice when looking north up the coastline was what looked like a satellite dish, and that got me wondering. Then I remembered we passed a single signpost on the way pointing to GCHQ. It turns out that just 6km up the coastline is GCHQ Bude.

A view of GCHQ Bude
A great View of GCHQ from the coastal path. Credit: Paul Phillips

Nestled between the small villages of Morwenstow and Coombe, during the second World War the Air Force built RAF Cleave. It was designed to house target and target support aircraft for the firing ranges along the north cornwall coast. After the war it then stayed in government hands, with little use. Then in the 1960’s it started changing. The main reason: in 1962 a satellite receiving station was established at Goonhilly Downs, mainly for linking with television satellites, it also carried large amounts of telecommunications data. A surprisingly important piece of satellite communications infrastructure it has played a key role in communications events such as the Muhammad Ali fights, the Olympic Games, the Apollo 11 Moon landing, and 1985’s Live Aid concert. Being only 100km south of RAF Cleave signals could be intercepted by placing receiver dishes on the grounds. Initially to intercept mainly signals from Intelsat, a commercial communications satellite, the construction of the station began in 1969, with two 27m dishes, with smaller dishes coming after. Initially signposted as CTOS Morwenstow (CTOS standing for Composite Signals Organisation Station), in 2001 when a third large dish was built the station was renamed GCHQ Bude.

RAF Cleave gun emplacement
Remains of an RAF Cleave gun emplacement, with the modern satellite dishes of GCHQ Bude behind

GCHQ Bude has come under fire many times because of the ethical implications of the work conducted there. Even as early as 1963 they could have been tapping the data classed as suspicious from the TAT-3 telephone undersea cable. There are cable landing points at Widemouth bay that connect the UK to the USA, just 10 km south of the Cleave camp. It was also featured in a BBC Horizons documentary where it is claimed that all the data that goes through that the internet landing cable at Skewjack farm in Cornwall (formerly RAF Sennen) is sent on to GCHQ Bude for processing. The Fiber-Optic Link Around the Globe cable that surfaces there is estimated to see around 25% of all internet traffic, just think about that for a second. In terms of satellite installations at GCHQ Bude there are twenty one satellite antennae of differing sizes, three of which having a diameter of 30m. In theory these dishes could cover all the main frequency bands. Based on the position, some have theorised that they are oriented towards satellites of the INTELSAT, Intersputnik, and INMARSAT communications networks over the Atlantic Ocean, Africa, and the Indian Ocean, as well as towards the Middle East and mainland Europe. As well as this in 2011 a torus antenna was installed which is able to receive signals from up to thirty five satellites at once.

GCHQ Bude facing East
A wide image of GCHQ Bude facing east with a sunset in the background.

This post is not about my opinion about what they do at GCHQ but I find it a very interesting place, with a serious amount of technology involved, but they have been in the news a lot. A report made public in 2001 showed concerns by some EU member states that CTOS Morwenstow was involved in industrial espionage. It is claimed that the Intelligence Services Act 1994 grants GCHQ access to anything that emitted an electromagnetic signal, so pretty much any electronic device. In 2011 the Guardian reported how GCHQ attempted to gain access to the Blackberry Messenger service for the use of police to trawl for riot organisers. In 2013 the Guardian reported a large amount of information about GCHQ Bude leaked by Edward Snowden. It talked about operation Tempora, where GCHQ tapped into undersea cables and kept the data for up to 30 days to assess and analyse it. A further article reported that it was eavesdropping on charities, German government buildings, the Israeli Prime Minister, and an EU commissioner. There are plenty of other similar articles out there with similar overtones, and about GCHQ in general. The thing I found crazy is that even though trespassing on the site is its own law, you can walk fairly close when going along the coastal path.

RAF Hartland Sign
A sign at one of the old radar stations at RAF Hartland Point, now used by the aviation authority. Credit: Exal66 on derelictplaces.co.uk

When researching this subject it can get into a deep pit of conspiracy, but the thing I enjoy the most is looking at old military installations. Just up the coast from Bude in the northwestern point of Devon is Hartland Point. We visited Hartland Quay (close by) and it is highly recommended for the views. Apart from the hundreds of shipwrecks along that coastline, a noticeable part of the view is the old radar station at the point. During World War 2 that was controlled by RAF Hartland Point. The foundations of the big type 11, 13 and 14 radars can still be seen around the radar station at the point. Great information about the radar systems and some more information about the base can be found here. There is also an old air raid shelter, and a former station building that has been commandeered by the coastguard. The radar that can be seen nearby (the spherical one) is used by the UK Civil Aviation Agency for air traffic control. A user on derelictplaces.co.uk shows some great images of his walk around the site.

RAF Hartland base
The base of a radar from WW2 at what was RAF Hartland point. The aviation authorities new radar is in the background. Credit Exal66 on derelictplaces.co.uk

The final place I want to mention is one that is very noticable to anyone who has called the Tarka Trail between Fremington and Bideford. It passes right across the river from the historical Appledore shipbuilders. With many owners and names in the 160 years it has been active, it is now owned and operated by Babcock international Ltd, the same company who run Devonport. The dockyard has built more than 350 vessels in its lifetime, including small and medium-sized military craft, as well as superyachts, bulk carriers, ferries and oil/LPG industry vessels. While we were there a Norwegian military ship was being worked on. Some of the most notable ships include HMS Echo, HMS Enterprise, HMS Scott, and RRS Charles Darwin. A trip down the Tarka Trail is highly recommended, especially by bike.

Appledore Babcock
The shipbuilders at Appledore, now owned and run by Babcock international, visible by the Tarka Trail.

Thank you for reading, take a look at my other posts if you are interested in space, electronics, or military history. If you are interested, follow me on Twitter to get updates on projects I am currently working on.


Delta II Launch Site Demolished

Delta II launch
The launch of the GRAIL mission from Launch Complex 17 by a Delta II. The final launch from SLC-17. Credit: NASA/Tom Farrar and Tony Gray

At 11:00 UTC on the 12th of July 2018 the two launch towers of Space Launch Complex 17 were demolished by controlled explosions. The crowd of onlookers cheered as the towers fell, and took some great images and videos of the demolition. The launch site had not been used since 2011 when Delta II 7920H-10C fired NASA’s GRAIL spacecraft towards the Moon. The launch complex had two pads named 17A and 17B. The site is now to be reused as a test bed for potential lunar landers made by Moon Express. Boasting some very prestigious missions well beyond Earth SLC-17 will be remembered as an important part of the history of American space.

Delta Echo 1
A delta Rocket carrying NASA’s Echo 1 satellite launching August 12th 1960. The Echo satellite inflated in orbit to reflect signals back to Earth. Credit: NASA.

It was built in 1956 for use as a launch site for the PGM-17 Thor missile. This was the first operational ballistic missile that the United States had in their arsenal. The first launch of a Thor missile from 17A was 3rd of August 1957, with the first launch from 17B being 25th of January 1957. In the early 1960s the site was upgraded to support a variety of Expendable Launch Vehicles, all of which were derived in some way from the Thor booster. We now know this family of rockets as the Delta rockets used by the United Launch Alliance. Thirty five early Delta rocket missions were launched from LC-17 between 1960 and 1965. At that point operated by the US Air Force. In 1965 the operation of the site was transferred to NASA.

View of LC-17
View of LC-17 viewing East. A fairly old photo taken by the U.S. Army Corps of Engineers. Credit: Martin Stupich

In 1988 the site was returned to the Air Force to support the Delta II program. The site had to be modified to facilitate the new more powerful rocket, with new platforms being installed and the D=Ground Service Tower was raised by 10 ft. The program entered service in 1989 after worries about the shuttle due to the Challenger disaster. Pad 17B was modified in 1997 to support a newer more powerful launch vehicle the Delta III which made its maiden flight on 26th of August 1998. Ending in failure, the next three attempts were failures in some sense and the programme was abandoned in late 2000. The Delta II continued to launch, with it’s fairly cheap price tag, and amazing track record it has been a favourite for NASA on a number of big projects. This post by NASA explains how the layout of the site and the small teams allowed LC-17 to be efficient and consistent over it’s 50 year lifespan. Some Delta II launches could be within days of each other because the launch crews were so effective.

Space Launch Complex 17
A view of Space Launch Complex 17, pads A and B taken in 2007. Delta II rocket with THEMIS aboard sits on Pad B. Credit: NASA/George Shelton

There have been some very famous spacecraft launched from SLC-17 in the years, mostly by Delta I and II rockets. Among them the Explorer and Pioneer space probes studying the physics of our solar system, and exploring some of it. All of the Orbiting Solar Observatories between 1962 and 1975 were launched from this site, as well as the Solar Maximum mission in 1980. Some of the first weather satellites like TIROS and later GOES were launched from SLC-17 allowing much better understanding of weather and improving (mainly military) weather reports. My personal favourite launches are those of the Mars Exploration Rovers in 2003. Both spirit and Opportunity (still going) were launched from this important launch site.

Spirit lifting off
A Delta II launching from pad SLC-17A with the MER-A or Spirit Rover towards Mars on June 10th 2003. Credit: NASA/KSC

Space Launch Complex 17 is also famous for being the last site where you had to press a button to launch the rocket. Most pads had a computerized auto-sequencer, much like the space shuttle, and in the modern world of rocketry it makes much more sense to do that. Even after 1995 when they got rid of the button (sadly) a human needed to press go on a computer to say launch. Bill Hodge, an electrical engineer at the launch complex said “If you didn’t push that button, it didn’t launch.” Tom Mahaney, project manager for the closeout of the complex described the site as “hectic, but not dysfunctional.” This is the best description I can find of this massively important historical site. In its time it has supported a total of 325 Thor and Delta rocket launches!

Thank you for reading, take a look at my other posts if you are interested in space or electronics, or follow me on Twitter to get updates on projects I am currently working on.


How the Moon’s Dust Could be Deadly

footprint on the moon
Very famous image of a footprint in the lunar soil, part of the 70mm Hasselblad image collection, you can see the dust and rocks that are classed as mature Regolith, Credit: NASA.

The space industry is changing, improving and looking at places to go. Although Mars is the big target for Elon Musk and SpaceX, revisiting the Moon is a big and real challenge that many are aiming for. Whether it is just getting people back there in a safer and cheaper way than Apollo or if it is companies wanting to design Moon bases, it is an active area of interest. Since the Moon landings over half a century ago, researchers have poured over the moon rocks, and images brought back from the mission. More recently though, researchers are looking at a slightly overlooked factor, lunar dust. They were a problem for the astronauts to landed there in the 60’s/70’s and they may pose a problem to future missions where they may spend weeks or months rather than just a few hours/days. The research below shows how the moon moon affects us when we are there, and how it could be very dangerous.

Harrison Schmitt collects samples
NASA astronaut Harrison Schmitt retrieving lunar samples using a scoop during the Apollo 17 mission in 1972. Credit: NASA.

At time of writing, twelve people have been known to walk on the Moon, all between 1968 and 1972. The longest any group spent on the Moon was the crew of Apollo 17 who spent just over three days there. Sleeping in the Lunar Exploration Module, the astronauts tended to collect lots of dust during the EVA’s (Extravehicular Activity). As the moon has a much lower magnetic field it gets blasted with much more radiation from the sun on the surface.  This electrostatically charges the dust particles making it much more likely to stick to the astronauts spacesuits. This linked with the lower gravity of the Moon means that the particles do not drift to the ground as fast like on Earth. Plus when the dust got into the Spacecraft it had no gravity on the trip home. All these factors meant that the astronauts inhaled lots of lunar dust during the mission.

Lunar dust particle
Fine like powder, but sharp like glass. An image of a lunar dust particle. Credit: NASA/JSC.

On earth, dust tends to be fairly round, eroded over time by wind and water. It is also not only rocks, but biological as well,  On the moon, the dust is just rocky and hasn’t been eroded over time as there is no wind or water. The particles are spikey, abrasive and nasty. All twelve of the people who landed on the moon suffered with what NASA astronaut Harrison Schmitt described as “lunar hay fever”. They had symptoms like sneezing, nasal congestion and often they took time to fade. Most people know that the astronauts describe the dust as smelling like burnt gunpowder, but don’t know that it made them quite ill. Even the astronauts themselves might not have known the true reasoning behind the illness. Part of the reason is that the lunar dust has silicate in it, often found on planetary bodies with volcanic activity. As well as making the astronauts ill, it was so abrasive that it ate away at layers in the spacesuit boots, and destroyed vacuum seals on sample containers.

Eugene Cernan Hay fever
NASA astronaut Eugene Cernan inside the lunar module, still on the moon after his second moonwalk of Apollo 17. With spacesuit covered in lunar dust he complained of hay fever like symptoms. Credit: NASA.

One study by Stony Brook University School of Medicine, NY looked into the toxicity and DNA damage as a result of exposure to Lunar dust. They attempted to mimic the effect of lunar regolith (the dust) on mammalian cells. They took lung and neuronal cells and then exposed them to materials processed to mimic lunar dust so they could assess survival and genotoxicity. They showed that the soil can cause death to some cells and DNA damage in both neuronal and lung cell lines. Certain forms of the dust had more effect than others, but it was shown that depending on conditions, lunar soil can be cytotoxic (toxic to living cells) and genotoxic (damages genetic information) to both neuronal cells and lung cells. Testing was done by cultures and not tested on real people or animals. Kim Prisk, a pulmonary physiologist from the University of California with over 20 years of experience in human spaceflight is taking part in similar research as Part of an ESA research program. She mentions that “Particles 50 times smaller than a human hair can hang around for months inside your lungs. The longer the particle stays, the greater the chance for toxic effects”. ESA make simulated moon dust from a volcanic region in Germany. See their post on Lunar dust here.

Thank You for reading, take a look at my other posts if you are interested in space or electronics, or follow me on Twitter to get updates on projects I am currently working on.


Charon: The Man Who Gave His Wife a Moon

Charon Enhanced
An enhanced colour version of Charon taken by New horizons space probe. It is enhanced to show the differences in surface composition. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

On June 22nd, 1978 James Christy was trying to refine the orbit of Pluto when he noticed something odd about the images. Going straight to Robert Harrington, his supervisor at the U.S. Naval Observatory in Flagstaff, Arizona, together they concluded that they had found what we now know as Pluto’s largest moon Charon. Discovered just 6 miles away from where pluto itself was found (Lowell Observatory), discovering Charon began a journey from Pluto being a dot on a telescope to its own planetary system. With some amazing images coming from a probe NASA sent there, we have a glimpse of the edge of our solar system. The best part of the story, Charon is named after Christy’s wife.

40 years after christy
40 years on, Christy shows the images he used to discover Charon, and now one of the New Horizons images is his PC wallpaper. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Art Howard/GHSPi

In 1930, Clyde Tombaugh discovered Pluto, and although famous in itself, there was limited study on this dot in the far reaches of the solar system. So on the fateful day James Christy asked his supervisor Bob Harrington for something to do, Harrington pulled some telescope plates of Pluto from the Naval Observatory at Flagstaff to look over. Christy looked over them for some time under a microscope and noticed some inconsistencies with the images, with the asymmetry being different between them. In simple terms he noticed a bump on the side of Pluto that seemed to move over time. Although at first he thought he might be seeing things, when he took it to Harrington he agreed with the findings.

Jim Christy points
Jim Christy pointing to the photographic plate that he used to discover that Pluto has a moon. Credit: U.S. Naval Observatory

When  looking at other images of Pluto, the bump was constantly moving from one side to the other. Further examination showed the bump moved around Pluto at the same own rotational period, 6.39 days. There were two potential theories as to what it was, either Pluto had a mountain thousands of miles high (meaning Pluto was not very spherical) or it has a satellite in synchronous orbit. In the 48 years since Pluto’s discovery at Lovell Observatory in 1930, there had never been any evidence spotted that Pluto had a moon. The next steps included scouring the archives for more cases of an elongated looking Pluto.

The Charon images
The discovery at the US Naval Observatory, Flagstaff was seen as a time varying bulge on the image of Pluto. This is a negative version of the one Christy looked at. Credit: US Naval Observatory.

Christy measured the angle from the north where the strange elongation was. At the same time Robert Harrington calculated what the answer would be if the elongation was from a satellite. They then compared their results, and they were the same. To be sure they waited for the Observatories 61 inch telescope to make a final confirmation on the matter. On the 2nd of July 1978 new images showed an elongation exactly where they expected it to be. Five days later they announced the discovery to the world. Pluto’s first satellite had been discovered.

40 years difference
The difference of 40 years, top left is one of the images Christy used to discover Cahron, the big image is from New Horizons flyby. Credit: U.S. Naval Observatory; NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

By astronomical tradition, the discoverer of an object gets the first chance to suggest a name for the object. The name does not have to be recognised by the International Astronomers Union. Christy wanted to name the moon after his wife, Charlene. To make it sound more scientific he took his nickname for her “Char” and added an “on”. The “on” was from his interest in atoms, and words like proton and neutron. He suggested the name on the June 24th, 1978. Colleagues at the observatory prefered the name Persephone, but Christy noticed that Charon was actually a real Greek mythological figure. Charon is the ferryman of the dead, associated with the god Hades. Creepily the Romans identified Hades with their god Pluto. The name was eventually adopted on January the 3rd 1986.

The greek Charon
The name Charon was partially adopted because it is the name of the ferrymen of the dead in greek mythology. this is a nineteenth century painting by Alexander Litovchenko

Charon is the largest moon of Pluto, and is about the size of Texas. It also makes Charon the largest moon relative to its parent planet at about 12% of the size. So big in fact that Charon and Pluto are seen as a double planet or binary planets. They have a common centre of gravity that is outside of either of them. It is believed that it was formed by some sort of giant impact, much like the Earth and the Moon. The sheer size and proximity to Pluto meant it was a good choice for a scientific mission to take a closer look at the system. The mission, New Horizons was launched in 2006, with a  primary mission to performa flyby study of the Pluto system.

New Horizons Artist
An artistic impression of what New Horizons looked like when it passed Pluto and Charon. Credit: NASA Goddard Media Studios.

Passing about 18,000 miles (29,000 km) away from Charon on the 24th of July 2015, New Horizons gave the world a brand new stunning view of the moon from up close. At its closest point it was 7,800 miles (12,500 km) from Pluto, mapping both the planet and the moon using its long range imaging cameras. It mapped them to a resolution of 25 mi (40 km). The way they entered the system and the speed they were going allowed them to map all sides of both bodies. They took multiple images with the close range camera to find any surface changes. They also characterised the atmosphere, using the on board ALICE experiment.

Best Charon Images
A mosaic of the best images taken by New Horizons of Charon, from a few different angles. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The science gained by New Horizons has given astronomers a new look into the outer reaches of the solar system, and it is still planning to take more images of comets and asteroids it comes into contact with in 2019. The first close up images of Charon were revealed  to the world at the John Hopkins Applied Physics Lab in Maryland to a packet auditorium. Jim Christy, the discoverer of Charon and his wife who it was named after were there at the unveiling, were recognized by the crowd. He said “When you go from this little blur in which you don’t actually see anything, to the enormous detail New Horizons sent back,” Christy said, “it’s incredible.” That amount of change in just 40 years.

The Secret of Salton Sea Naval Base

Salton Sea Base Sign
Welcoming visitors to Salton Sea Base while it was run by the Sandia Corporation.

Salton Sea Naval Base is not known as one of the famous military test sites in the United states. Although it isn’t as revered as places like White Sands or Edwards AFB it is still the location of some of the most important testing during the second world war. It aided in the development of the Fat Man, the bomb that eventually ended the second world war by destroying Hiroshima and Nagasaki in Japan. With many aerodynamic testing, and target practice for the bombers, at one point it was one of the most secret places in the United States, now it is basically a desert, with broken buildings, occasionally being found by urban explorers.

Building from the pier
A building found 100m up from the pier, showing signs of wear. Found by urban explorers recently. Credit: Saltonseawalk.

Salton Sea is a shallow saline lake located directly on the San Andreas Fault. The U.S. Navy inspected the site in January of 1940, and commissioned it as the Salton Sea Naval Auxiliary Air Station in October 1942. The base was designed as a training base for seaplanes, and was located just to the south east of Salton city. Although it only initially took claim of the northern end of the Lake, it eventually controlled part of the southern end too. Technically speaking it is a Naval Station and not a Navy Base, but most references refer to it as a Test Base.

Overhead view of Salton Sea in 1947
An overhead view of Salton Sea base in 1947.

View of Salton Sea base
Aerial view of Salton Sea boat docks, showing how remote the place is. Credit: Center for Land Use Interpretation.

Throughout the 1940’s it functioned as an active military weapons test site. Lt. Col. Paul Tibbets led the 393rd Heavy Bombardment Squadron during 1944 and 1945 through a series of classified B-29 practice flights from Wendover, Utah to the Salton Sea, where they would drop dummy atomic bombs onto a floating white raft. This was used as the testing site for the fateful atomic weapons attacks that ended the second world war for Japan. It is said that Tibbets dropped the first atomic bomb himself on Hiroshima in a plane named after his mum, Enola Gay. The prototypes were tested at Salton Sea.

instrument lab 1951
Image of the instrument lab of the Salton Sea Navy Base taken in 1951.

The crews made hundreds of practice runs over the Mojave and Salton Sea. The bombs they used were full size mock-ups, sometimes filled with concrete, other times containing everything except the nuclear part. This often meant being filled with explosives. During one Salton Sea run, an engineer dropped one of the Fat Man mock ups too soon. It narrowly missed the town of Calipatria. The bomb buried itself 3m into the ground, but luckily didn’t explode. Bulldozers rushed to the scene to erase the evidence.

UXO sign at Salton Sea
A sign warning of Unexploded Ordnance around the Salton Sea base area, with all the testing over the years it is understandable. Credit: Saltonseawalk.

Area Closed
A sign telling all visitors that the area is closed to all users.The guys who took the pictures ignored this warning though. Credit Saltonseawalk.

During the 1950’s the base was used by Sandia National Labs as a range for missile testing, with over 1,100 missile tests being conducted there. Sandia was the principal contractor for the Atomic Energy Commission after the war, and they renamed the site Salton Sea Test Base in 1946. They used the site to test weapons, space capsule parachute drops, drone airplane tests, and Nike missile launches. 150 different tests were conducted annually over a ten year period some using depleted uranium. Sandia ended operations in 1961 when they moved to a new remote site. The main reason for moving was a fight with rising waters of the lake.

Building A1
Located a few hundred meters into the base, Building A1 is one of the more interesting surviving buildings, you can see that it has not been looked after. Credit: Saltonseawalk.

Building A1
The building marked A1, one of the only buildings still standing. On top an Alaska Pedestal, used to hold tracking equipment for missiles. Credit: Saltonseawalk.

During the 1960’s it was mainly abandoned, and in the 1970’s it was occasionally used for live munitions practice.  Most buildings suffered substantial damage. The site was listed as inactive in 1986, but the facility found renewed life as a site for Gulf War training maneuvers during the 1990’s. As most of the original buildings were destroyed, the base was decommissioned and turned over the the U.S. Bureau of Reclamation in the mid-1990’s. The Site was used during the early 2000’s as a research site for salinity control. There are no plaques or monuments to the achievements of Salton Sea, and the parts it played in winning the second world war, and very little online about it.

Pier at Salton Sea
A great picture of what used to be the pier at Salton Sea base. Credit: Saltonseawalk.

Thank You for reading, take a look at my other posts if you are interested in space or electronics, or follow me on Twitter to get updates on projects I am currently working on.


Taking a Selfie on Mars

Curiosity in a dust storm
An image shared by Seán Doran on Sunday of the Mars Curiosity in the middle of a dust storm reported to cover an area the size of the US and Russia Combined. CredIt: NASA/JPL/Seán Doran.

Curiosity is a famous, car sized rover currently exploring Gale Crater on Mars. Famous because it has an impressive track record. Landing on Mars in August 2012, the rover was designed to last 687 days/668 sols (martian days) but was extended to indefinitely in December 2012. Although at the time of writing it is trying to wait out a dust storm that has forced Opportunity into a deep sleep, it is still going strong to this day, and has managed to even take a selfie while waiting for it all to blow over. That is over 2100 earth days, still functioning and completing chemical analysis on soil from 560 million km (350 million mi) away!

Mars Curiosity Rover MAHLI
The Mars Hand Hand Lens Imager (MAHLI) on NASA’s Curiosity Rover, taken by Curiosities Mast Camera on the 32nd martian day. Credit: NASA/JPL.

Curiosity first space selfie
The first selfie that Curiosity took of itself with its MAHLI camera with it’s dust cover closed. Taken September 7th, 2012. Credit: JPL/NASA.

Even though this impressive piece of engineering has been collecting samples and completing scientific experiments for over 5 years, the rover still has time to take the occasional selfie. It has a 2.1m robotic arm, and a sophisticated camera (MHLI) mounted on the end of it. The obvious thing you will notice about the images is that you can’t see the arm taking the image. To many of the NASA sceptics and flat earthers this is conclusive proof that the rover is in a film studio somewhere in California rather than on our nearest neighbour planet. At first glance you can understand the problem, where is the arm? The first clue is that the arm isn’t in the picture at all, and when you see the images taken of it here on Earth you can see it is a very prominent feature.

Mars Rover selfie October 2012
The Curiosity Rover taking a selfie at “Rocksnest” a sand patch on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons (“Mount Sharp”) Taken in October 2012, not long after landing. Credit: NASA/JPL.

The simple answer was explained by NASA/JPL when these questions came up after the first self shot. As the Curiosity camera has a limited view, it cannot get the entire rover into one shot, and even when it does, it looks slightly odd depending on the angle. This is also a problem that they have when taking images of the martian landscape. To get round it, the camera takes many images at differing angles. The images can then be stitched together in photoshop by engineers. They did something similar when putting together images of the moon taken by satellites. As the following image posted by NASA shows, the arm has to move during the changes in camera location, often moving out of frame. Even when the arm is slightly in an image they tend to cover it with another image, so it doesn’t confuse the people looking at it. The selfie would look odd if it had more than one arm showing.

Even though they take care to put together the images in a way that dont look like many stitched together there are still sometimes some inconsistencies. Notice that in the next image the shadow of the arm is still in the image, and there is a slight ghost of the arm below the rover. As you can see below this shot too 72 images stitched together to be made. 20 of those images, over 2 tiers just make up the horizon. Selfies are generally taken at each new drill site, as part of an overall effort to document the trip and of that site. The entire picture taking sequence has now been automated, and tested rigorously on the second identical rover that is here on Earth. If the rover were to take the multiple pictures from individual commands the process would be too long and drawn out.

Mars Rover Selfie August 2015
The Mars rover from a different lower angle. Taken at “Buckskin” on Aeolis Mons on
Mars. Taken on Aug. 5, 2015, during the 1,065th Martian day. Credit: NASA/JPL.

Mars rover selfie component images
The 72 images taken by the rover over the period of an hour. Credit: NASA/JPL/MSSS/Emily Lakdawalla.

There are at least 7 of these selfies taken over the years, all from a very similar angle. The big thing to notice is the difference in the rover itself. Over time it slowly gets covered in more and more dust, starting to blend in with the martian soil behind it. The saddest part to see is the slow deterioration of the wheels. There are small holes developing and getting bigger in the metalwork on the wheels, and in some images they can seem prominent. Either way, these selfies show a slight human side to the robot. There are many people throughout Twitter that anthropomorphize Curiosity and its predecessors, wishing them well on their journey.

Mars Rover selfie September 2016
A slightly newer selfie taken at “MurrayB” a named rock on
Aeolis Mons in Gale Crater. An awesome image taken in September 2016. Credit: NASA/JPL.

Thank You for reading, take a look at my other posts if you are interested in space or electronics, or follow me on Twitter to get updates on projects I am currently working on.


How the Type G Gate Worked

apollo 3 input NOR gate
An image of the silicon die inside the Type G 3 input NOR gate used to power the Apollo Guidance computer.

Previously I went through the three input NOR gate that ran the Apollo Guidance Computer and how the circuit works. Previous to that I also told the story of how this chip partially funded Silicon Valley as we know it today. This post builds on that and goes through how the silicon works, and the simplicity of the circuit. Quite a famous image of the chip, fairly detailed image of the silicon inside the device spurred on this post, and taught me lots about silicon that I want to pass on.

apollo 3 input NOR gate schem annotated
The schematic of the 3 input NOR gate. From the schematic of the Apollo Guidance Computer. Annotated with my own designators for reference.

The above schematic of the 3 input NOR gate is also shown in previous posts. It is from the NASA Apollo Guidance Computer schematic, but I have annotated it so that I can reference to specific parts. It is a handy schematic considering it was right at the start of the development of semiconductors. The first image in the post is the best image of the silicon, but is not very big. The biggest image I can find is not quite as sharp, but is much better to annotate, it is the same chip. The first annotation shows the pinout of the device, and how those pins actually connect to the pins.

apollo 3 input NOR pin out
The silicon of the 3 input NOR gate with annotations to show which pin is connected. The pin numbers are from the schematic.

Showing how pins are connected
An image showing how the pins coming off of the silicon are connected into pins of the flat pack.

The noted parts of the above images are pins 5 and 10, and are the starting points to deciphering the layout. If you look at pin 5 and 10 on the schematic, they correspond to GND and power respectively. They are the only pins that are shared between both NOR gates. Apart from that the two sides look remarkably similar, and are basically a mirrored version. To figure which is ground and which is power, the resistors need to be taken into account.

apollo 3 input NOR gate resistors
The resistors on the silicon of the device. Shown above as brown lines they are P doped silicon that act like a resistor.

The above image shows the resistors found on the device. They tend to just be a thin section of P doped silicon, and above connect two sections of aluminum to form a resistor. It is also noted that there is big section of brown surrounding the whole circuit. Although it functions like a resistor and is made in the same way, it is puterly for ESD purposes, protecting the circuit. This big ring also is a big hint that it is connected to ground (pin 5). the second hint is that GND has no resistors attached to it on the schematic, but power has two. They are R1 and R2, connecting to pin 9 and 1 respectively, and are pull up resistors. Pin R3 to R8 are simply the base resistors for the transistors. They are all roughly the same size, and are there are 6 of them. The transistors are also fairly obvious in the centre of the silicon.

apollo NOR gate transistors
The centre silicon from the Apollo 3 input NOR gate. The transistors have been shown, and the collector, base and emitter also shown,

The above image is showing the heart of the device. the 6 transistors that make it resistor-transistor logic. As you can see in the above image, all the collectors are connected together, connected to pins 1 and 9. If you look closely, the base and emitter of each transistor sit inside a brown section like the resistors. This is P doped silicon and forms the base-emitter junction. This allows the base and emitter to sit anywhere within that P doped silicon detection to work. This means that the transistors do not conform to the standard Collector-base-emitter topology. All of the emitters are also connected together via the aluminium placed on the top, but the P doped sections of each device are seperate. As all the transistors of each device have common emitters, it doesn’t matter that they are all connected together, by design, only one of the transistors needs to be on for it to function.

Ken Shirriff transistor side view
A great image showing how the transistor works from a side view by Ken Shirriff.

The above image found on Ken Shirriff’s blog shows how the transistor works with the emitter and base in the P doped silicon. I may do some more posts about it, but his blog is a great place to find more information on silicon reverse engineering.

Electronics world 1963
A cutout from electronics world in 1963 showing the new process of planar technology. This method was used to make the NOR gate.

The above image is an interesting one I found while researching this chip. A section in electronics world 1963 showing how micrologic is made. The type G chip was part of the second batch of micrologic circuits. This section was useful to see how silicon was actually manufactured, and in some ways, still is today.