The First Block 5 Launches Bangladesh’s First Satellite

F9-55 launches
An awesome image of the first Block 5 Falcon 9 taking off from LC 39A at KSC. Credit: SpaceX Flickr.

On the 11th of May 2018, at 20:14 UTC the first ever block 5 Falcon 9 rocket launched Bangabandhu 1 into geosynchronous transfer orbit. Launched from Launch Complex 39A at Cape Canaveral Air Force Base, the F9-55 (launch designation) was delayed after an automatic abort on May 10th, 1 minute before liftoff. Bangabandhu 1, a Thales Alenia Space Spacebus 4000B2 series satellite is Bangladesh’s first geostationary communications satellite.

The block 5 has been long awaited by SpaceX fans, with many images in the news, and plenty of hints on Twitter. SpaceX has been incrementally improving and upgrading the Falcon 9 v1.2 booster design since it’s first launch in December 2015. Designed to be much easier to refurbish, with potentially 10 reuses in each booster. Previous block designs have only been able to be reused once before being decommissioned.

F9-55 on the pad
The F9-55 on the launchpad ready to fire a satellite into GTO more efficiently that previous versions. Credit: @marcuscotephoto on twitter.

The Block 5 incorporates higher thrust Merlin 1D engines that have turboprop modifications that were requested by NASA. These modifications are to accommodate future potential crew launches. Another big change was mentioned in the livestream, where the pressurisation method in the second stage has been improved. After the AMOS 6 Falcon 9 explosion, the new version allows for faster, later and denser, chilled kerosene fuel loading. It also has new landing legs that can be retracted without being removed like previous Falcon 9’s. There are other changes, but they have been featured in previous designs.

F9-55 launch
The Falcon 9 takes off with Bangladesh’s first geostationary communications satellite on board. Credit: @marcuscotephoto on Twitter

The first stage had designation B1046. It burned for 2 minutes and 31 seconds, before separating ro perform reentry burns. It opened its new landing legs and landed on the autonomous drone ship Of Course I Still Love You, 630km downrange in the ocean. The second stage burned for 5 minutes and 43 seconds to reach parking orbit at T+8 minutes and 19 seconds. It then restarted ar T+27 minutes and 38 seconds for a 59 second long second burn that accelerated the craft to GTO.

F9-55 awesome shot
The Falcon 9 after an aborted launch the day before, with a new paint scheme to denote the block 5. Credit: SpaceX Flickr.

In the 31 attempts, 25 Falcon 9/Falcon Heavy booster have been successfully recovered. Four of the landings have been on “Just Read The Instructions” off the coast of California. 10 on land at Cape Canaveral from LZ1 with another one on  LZ2. 10 have landed on the autonomous drone ship, Of Course I Still Love You off the Florida coast. Nineteen individual first stages have been recovered, eleven have flown twice, with five of those ether expended or lost during their second flights. All the recovered stages have been v1.2 Falcon 9’s.

F9-55 power
The first look at the extra thrust on the Falcon 9 Merlin 1D engines in the new Block 5. Credit: SpaceX Flickr.

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

The Manned Orbiting Laboratory

NASA Special Agent Dan Oakland holds up a long-lost spacesuit uncovered at the Cape Canaveral Air Force Station (CCAFS) in Florida. Credit NASA.

In early 2005, two security officers at Cape Canaveral Air Force Base in Florida were doing a check of a facility known as the Launch Complex 5/6 museum. NASA Special Agent Dann E. Oakland and Security Manager Henry Butler, of the company that oversees the museum, Delaware North Parks and Resorts, discovered a locked room. The problem was they had no key, and nobody else did! Luckily, being security officers they found a master key and gained entry. By the looks of things the room hadn’t been accessed in  many years, at least not by people, the rodents had made themselves at home. With no power the officers explored with torches and found some interesting stuff.

This is Launch Complex 5/6 blockhouse, now a museum at the Cape Canaveral Air Force Station (CCAFS) in Florida, where long-lost space suits were found. Credit: NASA.

They found retired spacesuits designed for Americans in the 1960’s that were training to be space spies. Initially they assumed the spacesuits were training suits from the end of Gemini or the beginning of Apollo space programs. When inspected by their manufacturer, the Hamilton Standard Corporation, they determined they were actually MH-7 training suits. Kept in surprisingly good condition, the suits were made for a short lived cold war-era military program to put a manned space station in orbit.

This locker reveals a long-lost spacesuit uncovered at the Cape Canaveral Air Force Station (CCAFS) in Florida. Credit: NASA

In 1964 the Manned Orbiting Laboratory program was an Air Force initiative to send a Air Force astronauts to a space station in a Gemini capsule, as they had plenty of experience with it. While up there they would take part in surveillance and reconnaissance efforts. After spending a few weeks in orbit, the crew would simply un dock and return to Earth. A test launch from Complex 40 on Nov. 30, 1966, of a MOL was conducted with an unmanned Gemini capsule. The MOL was constructed from tankage of a Titan II rocket. The program was abandoned by the Air Force in 1969 but not before they made a great deal of technological developments. when the USAF abandoned the MOL program, they transferred all equipment and their astronaut corps to NASA.

A 1960 conceptual drawing of the Manned Orbiting Laboratory. Credit: NASA

There were two spacesuits found, one identified as 007 and another 008. The spacesuit with identifying number 008 had the name “LAWYER” on the left sleeve. The suit was traced to Lt. Col. Richard E. Lawyer, a member of the first group recruited to be MOL astronauts in 1965. Three groups of military officers trained to be MOL astronauts, when the program was cancelled seven of the younger ones were transferred to NASA’s human space flight program, and went on to have standout careers. Notable mentions are Robert Crippen, pilot of the first Space Shuttle mission, and Richard H. “Dick” Truly, who later became a NASA Administrator. All MOL astronauts who were under age 35 and survived eventually flew in NASA programs, either on board Skylab or the space shuttle.

Atlas V Launches InSight

Atlas V on the pad
The Atlas V on the launch pad at vandenberg AFB in California, Credit: ULA flickr.

At 11:05 UTC on May 5th 2018 the forth Atlas launch of the year launched the long awaited InSight mission on a course for mars. Launching from Vandenberg Air Force Base the AV-078 (the launch designation) was an Atlas V in 401 configuration. It was the first interplanetary launch from the west coast of the United States. Liftoff of the Atlas V with a 4m payload fairing was from Space Launch Complex 3 East.

Sam Suns first tweet
An awesome photo of the launch that blew up on twitter, taken from the sky. Credit @BirdsNSpace on Twitter.

The rocket had one main payload, the InSight Mission and two CubeSats. InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) is a robotic lander designed to study the interior of the planet Mars.  I weighed 694 kg at launch, including a 425 kg fueled lander. The lander carries a probe that will be hammered 15m into the Mars surface, a seismometer, a magnetometer (first expected to land on the surface of Mars), a laser reflector, along with other instruments. The lander also has a robotic arm to move payloads around, but there will be another post in the future discussing the instruments in more detail. The two CubeSats on board are known as MarCO-A and MarCO-B, each weighing about 13.5 kg. They will fly by Mars while conducting a data relay experiment with InSight.

Insight Fairing
The 4m payload fairing on top of the Atlas V containing the InSight payload. Credit: ULA Flickr.

The design of InSight was developed from the 2008 Phoenix Mars Lander. The previous lander was launched on Delta 2 rockets compared to the Atlas V, both built and launched by the United Launch Alliance. The Atlas V does have excess capability for the mission (slightly overkill) but this allowed it to be launched from Vandenberg AFB. Previous solar orbit missions (like this one) were launched from the Cape to gain the site’s eastward earth rotational velocity. Vandenberg launches have to fly south or westerly direction across the Pacific Ocean. InSight was originally planned to launch in 2016 but was delayed to 2018 due to the main instrument failing.

Liftoff od Insight
The Atlas V lifts off, unfortunately the fog rolled in so very few great shots were taken by the remote cameras. Credit: ULA Flickr.

AV-078 started on a 158 degree azimuth, aiming towards a 63.4 degree Low Earth Parking Orbit. The LOX/RP-1 fueled RD-180 powered first stage fired for 4 minutes and 4 seconds. The Centaur’s RL10C-1 LOX/LH2 engine then fired for 8 minutes and 48 seconds to reach the parking orbit. It then coasted for 65 minutes and 40 seconds then performing a second, 5 minute and 23 second burn to accelerate into a trans-Mars solar orbit. Insight separated 9 minutes after at about T+1 hour, 33 minutes and 19 seconds. The CubeSats separated shortly after.

Aaron Colier Atlas V launch
An awesome long exposure shot of the launch taken by Aaron Collier. From roughly 85 miles away. Credit @aaroncollier96 on Twitter.

Final Rokot Launches Sentinel 3B

What Sentinel 3B looks like
Artist’s view of what Sentinel 3B looks like when up in space, sadly there are not many images of it for real! Credit: ESA/ATG Medialab

On April 25th, 2018, at 17:57 UTC a Russian Rokot/Briz KM rocket launched from Site 133, pad 3 from Plesetsk Cosmodrome. Aboard was Sentinel 3B, an Earth observing satellite, part of Europe’s Copernicus environmental monitoring network. This marks the final commercial Rokot Launch, and the final Eurokot mission. There are some more Rockot launches planned for the Russian government though, after which it is reportedly that the repurposed missile launch system will be retired.

Sentinel-3B UC exit from MIK go to Launch pad
The Sentinel 3B being transported to the launchpad by the russian train system.

Sentinel 3B is a Thales Alenia Space Prima Bus satellite, designed to measure ocean temperatures, colour, surface height and the thickness of sea ice. While it is over land it can measure the height of rivers and lakes, monitor wildfires, provide maps of land use and monitor vegetation. The satellite has been designed for many uses. Created for the European Space Agency, the satellite will join Sentinel 3A in orbit to symmetrically monitor the Earth. The data will be primarily fed into the Copernicus Environmental Monitoring Service, where the applications can be developed from to use the data.

Sentinel 3B in integration
An image of the Sentinel 3B satellite just before it was sent off to Russia to be put on the Rokot. Credit ESA

The satellite carries many payloads to track the huge amount of data it is recording, these include:

  • OLCI (Ocean and Land Colour Instrument)
  • SLSTR (Sea and Land Surface Temperature Radiometer)
  • SRAL (Synthetic Aperture Radar Altimeter)
  • MWR (Microwave Radiometer)
  • LRR (Laser Retroreflector)
  • GNSS (Global Navigation Satellite System)

Thales Alenia Space was the prime contractor, responsible for constructing the spacecraft and the SRAL instrument, as well as contributing to the supply of the SLSTR instrument. Many European companies were involved in supplying the SLSTR instrument, including SELEX Galileo, RAL (Rutherford Appleton Laboratory), Jena-Optronik, Thales Alenia Space, ABSL and ESA-ESTEC. EADS CASA Espacio was contracted to provide the MWR instrument. CNES was contracted to provide the DORIS instrument.

Mediterranean Sea
An image of the Mediterranean Sea taken by Sentinel 3A, the partner of Sentinel 3B, they will don the same job on opposite sides of the Earth. Credit: ESA

When Planes Need an Eye Test: NOLF Webster.

webster overall map
From Google Maps. the locations and distances between the 4 photo resolution markers. Taken in 2007.

In a previous post, I put together lots of images of photo resolution markers, from across the USA. This post is about the four markers found at a little known airfield named Naval Outlying Field Webster in Maryland. In posts on this subject in other blogs it is often incorrectly named Walker Field, just to make things confusing. The four markers are in a straight line, with an almost exact 2000ft between them. This is likely for some sort of calibration testing, so the planes have an exact known distance to calibrate their cameras from. They are in parallel with one of the main runways to make it easy to maintain them, and as another reference for the planes.

Photo res marker 1
The most eastern photo resolution marker at Naval Outlying Field Webster. Taken in 2007 by Google Maps.

NOLF Webster is located 12 miles south west of Naval Air Station PAX River. It was bought by the military from a set of jesuit fathers during WW2 for just $96,000. It was bought as a auxiliary airfield for PAX River, to send aircraft to on busy days. PAX River is a very famous aircraft testing base, with lots of history associated with it. Part of the history is the photoreconnaissance training school found there. That explains the reasoning for the photo resolution markers just 12 miles to the SW.

Photo res 2
The second photo resolution marker at Naval Outlying Field Webster. Taken in 2007 by Google Maps.

NOLF Webster is good as an air base due to it’s great location. It has a good approach by water from two sides, especially good for testing and training. The other approaches were mainly woodland and fields. The three runways are built in accordance with the prevailing winds, with two of the runways being 5,000ft long. The base was heavily used in the 1950’s as a ‘touch and go’ site for training at PAX.

photo res 3
The third photo resolution marker at Naval Outlying Field Webster. Taken in 2007 by Google Maps.

In the 1960’s the former electronics test division moved in, now known as Naval Air Navigation Electronics Project (NANEP). They helped develop many air navigation systems. They stopped the interference with operations at PAX River. They may also have been a big part on the development of the photo resolution markers found there.

photo res 4
The fourth photo resolution marker at Naval Outlying Field Webster. Taken in 2007 by Google Maps.

Most of the images I have used are taken in 2007, but the final one (of the fourth marker) is taken in 2015, where it has a slightly different pattern. This is maybe to define markers between each of them, so the planes know the final one. There don’t seem to be any other changes according to the images found on Google Earth.

photo res 4
The fourth photo resolution marker at Naval Outlying Field Webster. Taken in 2015 by Google Maps.

Hope you enjoyed this short post, If you enjoy stories and posts on space and electronics, take a look at some of the other posts on my blog. Thank You for reading.

The Foundry: Put a Lid On It

In the previous foundry post, we made the foundry hugely more efficient by adding a fan to force air into it using an old hairdryer. Although it made the fire super hot it introduced many problems. It forced the tiny pieces of ash sitting in the foundry into the air, and towards anyone in a 2m radius. Some of the fuel also gets forced out which makes it less efficient. Bad all round, especially for the neighbors clothes on the washing line, which probably smelt smoky after each burn. We came to the conclusion that we needed a lid to hold in that glorious heat.

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

We went to the internet and found the easiest way to make the lid is to just make it in the same way we made the foundry itself, but with a few modifications. Firstly we made much less, we only want a lid about an inch thick (2.5cm) for a lid. This size was thick enough to be strong, but not so thick that it was unusable. We also used a plastic bucket rather than a metal one. As plastic can be bent it allows some movement to get the set lid out of the bucket without breaking either. You also need something to make the hold in the centre, we used a bottle, but if you can find something with a nice base then use that, the bottle had its drawbacks. Make sure the item you use can be ruined, and has a slight taper, because it needs to come out when the lid is set. Once put together we left the lid for a day to set, just like with the foundry.

The new lid
The new lid sitting inside the bucket setting, with the bottle in the centre to make the hole.

As you can notice in the above image we added a way to pick up the lid. This is firstly really useful to take out of the bucket, but will also be useful when we are actually using the forge and things get hot. It is much easier if we have something to actually grab on to. We used standard off the shelf D rings from ScrewFix, but anything that has a good ring and plenty of metal for the mixture to mould around then it should work fine. For us, it made the act of picking up the lid much easier.

the first lift test
The first attempt to lift the lift after it had been taken out of the bucket.

So once it was out, we left the lid out of the mould overnight, and then tried it out the next day. For the first burn with it we were gentle, and barely put on the hairdryer. This was to make sure that we didn’t damage it, we really wanted to help the curing process. You can see the difference in the below picture though, all the heat is confined inside the forge, and no ash or particulate is coming out the top. To add or remove the lid from the top we used kitchen tongs, as the D rings get very hot. We also hd head gloves to make sure we didn’t burn ourselves in the process. Safety is paramount if doing this yourself. It is easy to make a new lid but it isn’t easy to fix third degree burns! you have been warned. That being said, from our perspective that is a working forge! Now onto melting things.

The lid setup
The full setup, with the lid on it , the first burn was much gentler to allow the lid to set better, we though an extrer first burn could damage it.

Hope you enjoyed this post, hopefully there will be another update soon, but for now search the rest of the blog, as there are some awesome images of rockets, interesting history about aerospace, and you might learn something about electronics. Thanks for reading.

The Exoplanet Hunter TESS Launched by Falcon 9

TESS taking off
The Falcon 9 taking off from SLC-40 at Cape Canaveral with TESS on board. Credit: SpaceX Flickr.

On April 18th, 2018 at 22:51 UTC a Falcon 9 took off from Launch Complex 40 at Cape Canaveral AFB. Aboard was NASA’s latest research satellite TESS. A mission that cost $337 million, Transiting Exoplanet Survey Satellite (TESS)  is the latest in a line of space based observatories that are set to launch this decade. Launched into an arching elliptical orbit that will take the spacecraft over two thirds of the distance to the moon. The first stage of the Falcon 9 landed on the autonomous drone ship Of Course I Still Love You to be refurbished and reused.

falcon 9 engines
The sheer power of the Falcon 9’s nine Merlin 1D engines produce an awesome inferno. You can clearly see the 45 written on the side as the booster designator. Credit @marcuscotephoto on Twitter.

After a 5 day checkout of the spacecraft, basically a hardware check, the ground controllers will switch on the TESS cameras. TESS is designed to scan around 85% of the sky during the two year mission, with astronomers estimating as many as 20,000 new planets could be found. It plans to build on discoveries made by NASA’s Kepler telescope which was launched in 2009 to find earth like planets. TESS carries four 16.8-megapixel cameras, and will look for dips in light coming from 200,000 preselected nearby stars. The four cameras cover a square in the sky that measures 24 x 24 degrees, wide enough to fit the Orion constellation into a single camera. the cameras together study a set area of sky for 27 days before staring at the next section.

TESS orbit
An illustration of the orbits that TESS will go through to get to the final orbit P/2. Credit: NASA.

The orbit TESS is being launched into is known as P/2, and requires time and finesse to reach. TESS will slingshot by the moon at a distance of around 5,000 miles (8,000 kilometers), using gravity to reshape its orbit, increasing the satellite’s orbital perigee, or low point, to the final planned altitude of around 67,000 miles. After the lunar flyby, the high point of the satellite’s elongated orbit will stretch well beyond the moon, and another thruster firing will nudge TESS into its final orbit in mid-June. Science data is planned to start in july, with the first year of the two year campaign aimed at the stars in the southern sky. TESS has been built to have enough fuel to last 20 or 30 years, assuming funding by NASA and the components on board continue to function correctly.

the TESS telescope
The TESS satellite before launch, the four cameras can be seen on the top of the spacecraft; Credit: NASA.

Each of TESS’s cameras have four custom built re-sensitive CCD sensors designed and developed by MIT’s Lincoln Laboratory. The sensors are claimed to be the most perfect CCD’s ever flown by a science mission. The lenses used by the cameras are only about 4 inches (10mm) wide, meaning it has a fairly low light collecting power compared to other space telescopes. The James Webb Space Telescope for example launching in 2020 had a 21.3ft (6.5m) primary mirror, although the satellite has cost over $8 billion to make. TESS is a bit like a finder telescope, it will lay a bedrock for future missions such as Webb and ground based observatories to make better readings. It gives a good idea of the best places to look, where the most likely exoplanets are.

launch of TESS
The Falcon 9 launching the Transiting Exoplanet Survey Satellite to an orbit of P/2. Credit: SpaceX Flickr.

TESS works by looking at a star, in this case mainly M-dwarf stars, which are cooler than our sun. They are also known as red dwarfs and make up most of the stars in our galaxy. When a planet goes in front of the star the light received by TESS “dips” and changes slightly in colour. This change in the light it receives can tell scientists alot about the size of a planet, and other things like density and velocity. They expect TESS to find between 500 and 1,000 planets that are between one and three times the size of Earth, and 20,000 planets the size of Neptune or Jupiter. The readings will give a good idea of where to focus on and ‘follow up’ on future missions. Then missions such as JWST can probe and use more complex tools to find information such as atmospheric composition, and whether they could be habitable.

long exposure TESS
A long exposure of the Falcon 9 taking off over the SpaceX hangar at Cape Canaveral. Credit: SpaceX Flickr.

The Falcon 9 used was a v1.2 with designation F9-54. It used a brand new “Block 4” first stage. The booster designated B1045 has a clear 45 written on the side in some of the close up booster images. The fist stage boosted for 2 minutes and 29 seconds, then detaching and slowing itself down. The booster landed downrange on the autonomous drone ship “Of Course I Still Love You”. The first successful drone ship landing since October 2017. A total of 24 Falcon 9 or Falcon Heavy booster stages have now been recovered in 30 attempts. Four of which were on “Just Read The Instructions” off the coast of California, ten at Cape Canaveral Landing Zone 1 and 2, and nine on the autonomous drone ship “Of Course I Still Love You” off the Florida Coast. 18 first stages have been recovered, 11 of which have flown twice, five have been lost during their second flight. B1045 was the last brand new “Block 4” Falcon 9 booster.

TESS taking off
An awesome photo of a Falcon 9 taking off from across the water, a perfect day for pictures! Credit: SpaceX Flickr.

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

Atlas 5 Launches a Trio of Spy Satellites

Atlas 5 taking off
Atlas 5 lifting off from pad 41 at Cape Canaveral Air Force Base. Credit: @marcuscotephoto on Twitter

At 23.13 UTC on April 14th 2018 the third Atlas 5 launch of the year fired multiple military satellites into a near geosynchronous orbit. Launching from Space Launch Complex 41 at Cape Canaveral, FL,  the AV-079 (the launch designation) was an Atlas V in 551 configuration. The rocket had 5 solid rocket motors, a Centaur second stage powered by a single RL10C-1 LOX/LH2 engine, and a 5m diameter payload fairing. The entire mission lasted approximately 7 hours and is known as Air Force Space Command (AFSPC) 11 mission.

The Atlas 5 AFSPC11
The Atlas V carrying AFSPC11 for the Air Force Space Command. Credit: United Launch Alliance Flickr.
the smoke trail
A smoke trail left by the Atlas V as it launches a trio of spy satellites. Credit: @marcuscotephoto on twitter.

The mission lifted two primary satellites for the Air Force, one stacked on top of the other. On the top was CBAS (Continuous Broadcast Augmenting SATCOM) an abbreviation within an abbreviation, and a military communications satellite. The second satellite was named EAGLE (ESPA Augmented GEO Laboratory Experiment) which is an abbreviation with two abbreviations in it! This satellite is based on an Orbital ATK ESPA bus, it is a research laboratory that can host 6 deployable payloads. It is said that EAGLE likely weighed around 780 kg. There was also a subsatellite named “Mycroft” reported to be on the flight, but not confirmed.

The fury of the Atlas V
The fury of the 5 solid rocket boosters found on this Atlas V. Credit: United Launch Alliance Flickr.

The Solid motors finished their burn and seperated 1 minute and 47 seconds after liftoff. The first stage,  an RD-180 rocket fired for 4 minutes and 33.5 seconds. Centaur then performed 3 burns which were not shown on the livestream. The first burn was meant to last 6 minutes 1 seconds to reach a low earth parking orbit. The second burn began 12 minutes and 6 seconds after the first cutoff, and last 4 minutes and 49 seconds, putting the vehicle into a geosynchronous transfer orbit. After a 5 hour and 6 minute apogee, a third burn of 2 minutes and 36 seconds completed the insertion to the planned orbit. A spacecraft separation extended for another 1 and a half hours to T+6 hours 57 min 24 sec.

Atlas v launchpad
Atlas V rolling to the launchpad at Space Launch Complex 41 at Cape Canaveral AFB. Credit: United Launch Alliance Flickr.

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

The NOR Gate That Got Us To The Moon

Type G micrologic
The Fairchild Type ‘G’ Micrologic gate for the Apollo Guidance Computer – this is the flat pack verison

In a previous post I talked about how the going to the moon kick started the silicon age. If you haven’t read it, it is short but really interesting story about how NASA made Integrated circuits cheap, and partially funded what we now know as Silicon Valley. In this post I am going to take a slightly closer look at the circuit that ran the famous type “G” Micrologic gate that ran the Apollo Guidance Computer.

apollo 3 input NOR gate
The official NASA schematic of the Type G micrologic gate found in the Apollo Guidance Computer

As you can see in the above image, the circuit was not particularly complicated. You have to remember that this is very early logic, before CMOS or NMOS or any other fancy IC technologies. This is basically two 3 input NOR gates, they both run off the same power, with pin 10 at the top, and the negative which was likely ground being shared on pin 5. The output for the left NOR gate is pin 1, and the output for the right is pin 9. The three inputs for the left are pins 4, 2 and 3, with the right having pins 6, 7, and 8 as inputs. Simply put, the output is “pulled” high to power when all the inputs are OFF. The resistor between pin 10 and pin 1 (or 10 and 9) are a simple pull up resistor as you would find in most electronic circuits. As expected with a NOR gate, the output will be only be ON when all the inputs are OFF. When any of the inputs are ON the output of that gate will be pulled to ground. One two, or all the inputs can be on, but it just needs one to turn OFF the output. The resistors going into the base of the transistor are just to limit the current.

3 input NOR
My breadboarded version of the 3 input NOR gate, it is made with BC547 transistors and a DIP switch. the output has been inverted with the LED.

I made a simple recreation of this circuit using BC547 NPN transistors, but most NPN transistors would work, these were ones I found in my parts box. As you can see in the image above, I have made it on a breadboard, with the inputs being a DIP switch attached to the power (5V in this case). The base resistors for the transistors are 1K and the pull-up to 5V is a 10K. I recommend making up this circuit if you want to learn a bit more about logic, and is a cheaper method than going out to buy 74 series logic chips! As you can see in the images there are a number of states that I showed the circuit in, and notice that if any of the switches are on, the circuit turns on, this is slightly against what I mentioned earlier, but thats due to the output LED using the transistor as a current sink, not a source, so the output is inverted. Basically, when the output is 0 the LED turns on. The only time the LED is off (output high) is when no switches are on, meaning all the transistors are off.

apollo 3 input NOR gate
An image of the silicon die inside the Type G 3 input NOR gate. We will be going through how the layout works in a future post.

The final point for this post is why the circuit is actually quite efficient. Modern logic is amazingly low power compared to this. One of the biggest issues is that it is always taking power in some way. When the inputs are off, there is still some leakage through the pull up resistor, when an input is on, then there is current going through the resistor to ground. Also, by the nature of the transistors there is always parasitic leakages, and inefficiencies in the process. They are only small numbers, but the AGC used over 3000 of these circuits, so the small leakages soon add up to draw some hefty power needs, especially for battery powered operations.

If you enjoyed this post, take a look at the rest of my blog, there is lots about space, electronics and random history. I am always open to ideas and feedback, and where is best to post links to my posts.

VA242: Ariane 5 Launch

VA242 launching
VA242 launching with two satellites aboard weighing almost 10 tonnes. Credit: Arianespace Twitter.

At 21:34 UTC on the 5th of april 2018, an Ariane 5 with ECA vehicle number L5102 launched two communications satellites into orbit. The successful flight launched from Kourou in French Guiana from Pad ELA-3. The mission named VA242 placed Japan’s DSN 1/Superbird 8 and Britain’s Hylas 4 into their planned orbit. VA242 was the 64th Ariane 5 ECA success in 66 flights. Both satellites were placed in a 250 x 35,786 km x 3 deg geosynchronous transfer orbits about 34 minutes after takeoff.

Ariane 5 liftoff
Ariane V L5102 lifts off from Kourou in French Guiana on April 5th. Credit: Arianespace twitter.

The Japanese DSN 1/Superbird 8 is designed to provide X-band communications for the Japanese Ministry of Defence. It will also provide Ku and Ka band commercial services for Sky Perfect JSAT Group from 162 degrees East. The satellite is a NEC Corporation DS2000 series, weighing 5,348kg.

Ariane V launch
VA242 lifts off from pad ELA-3 at 21:34 UTC placing a Japanese and British satellite into Geosynchronous Transfer Orbit. Credit: ArianeSpace Twitter.

The British Hylas 4 was built for British-based Avanti Communications, is designed to provide Ka band communication services to Europe and Africa from 33.5 degrees West. Designed by Orbital ATK it is a GEOStar 3 series weighing 4,050 kg.

Birds flying
Birds flying away as VA242 launches from French Guiana. Credit: Arianespace twitter.