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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 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 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.
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.
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.
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.
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.
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.
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.
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.
On Thursday 5th of April 2018, Virgin Galactic’s SpaceShipTwo conducted its first powered test flight of 2018. With very little in the media from Virgin Galactic recently, this has been a welcome development in the field of space tourism, and the development of space planes. Named the VSS Unity, this space plane is the newest development from the Spaceship Company.
Virgin Galactic hasn’t performed a powered test flight since 31st of October 2014 when the VSS Enterprise experienced a catastrophic mid flight failure. The incident in the first of 5 planned SpaceShipTwo aircraft ended with a tragic accident which resulted in the death of one test pilot and serious injury to the other. With the program many years behind schedule, many critics thought this could have been the end for Virgin Galactic. Fortunately, Virgin Galactic have said the fault was not in the hardware, and was a change in safety procedure rather than a design overhaul. Over the last year, Virgin Galactic has made significant progress, leading to this powered test flight.
An NTSB investigation into the accident concluded that a pilot prematurely deployed the feathering system on the spacecraft. The system is used to increase drag during reentry. Many have criticised Scaled Composites (the manufacturer) and Virgin Galactic for not having fail-safe’s in place to prevent this problem. This is what lead into the review into the safety of the craft. After the loss of the USS Enterprise, and the safety reviews, the USS Unity was not ready until february 2016. This was the first plane to be built in house by The Spaceship Company.
Up until this point the testing has been more gradual than planned, with captive carry tests, and a total of 6 successful glide tests. There was a dry run rocket test on 4th of August 2017, where water was mounted in place of rocket fuel to simulate the shift in gliding with various centres of gravity, as well as the change of weight as the rocket uses up the fuel. These tests ended positively, with the Chief pilot David Mackay stating “We are really pleased with what we saw today. We collected hundreds of gigabytes of data for us to review, and from the pilots’ point of view, it felt really wonderful.”
The FAA approved a revision to Virgin Galactic’s Commercial Space Transportation Licence in 2017. This allowed Virgin Galactic to launch out of Spaceport America in New Mexico as well as Mojave Air and Space Port in California. Virgin also announced that the Kingdom of Saudi Arabia would invest $1 billion across the Spaceship Company, Virgin Galactic and Virgin Orbit.Currently under review, if approved the deal would help finance SpaceShipTwo during 2018.
VSS Unity is powered by a hybrid rocket engine called RocketMotorTwo. The engine originally used rubber based hydroxyl-terminated polybutadiene (HTPB) as the fuel, and nitrous oxide as the oxidiser. In 2014 Virgin Galactic switched to a plastic based thermoplastic polyamide for the fuel to improve performance. Although tested, and not the cause of the crash of VSS Enterprise, Virgin Galactic opted to use HTPB after extensive testing at Mojave.
The test used WhiteKnightTwo to lift the VSS Unity to an height of 50,000 feet, then release it. Once clear, VSS Unity ignites and ascends rapidly. The burns during the real flights will last just over a minute, but this test used a much shorter burn. This is the incremental approach that Virgin Galactic have opted for. Unlike a normal rocket, the engine thrust will decrease over time, so that the G-forces stay reasonably comfortable, as this is meant to be a pleasure ride. Once the engine cuts off, the craft coasts to the apogee and glides back to the spaceport. The tests can only get the craft to 80 km, which is not officially recognised as space, due to the extra test equipment needed. Virgin Galactic claim to be confident that the craft will reach space in the final version.
Peter Beck is the CEO and founder of Rocket Lab, a US/New Zealand orbital launch provider who is trying to provide access to space for small satellites. On at 19:00 UTC on April 5th he participated in a Reddit AMA on /r/space, where he answered as many questions as he could about the Electron launch vehicle and the upcoming ‘it’s business time’ launch, as well as what the future of space access looks like. It was a good AMA, he answered lots of questions, and the full post can be found here. This post is to round up some of the most common and important questions he got asked for those interested.
The most questions came with reference to SpaceX, and the way their business model compares to Rocket Lab.
SpaceX didn’t see a market – It’s known that the Falcon 1 was a similar size to the Electron and they quickly moved on from it. So people asked if SpaceX didn’t stay with it, why will it work for Rocket Lab? Peter makes the point that SpaceX retired that rocket 10 years ago, and most of Rocket Labs customers didn’t even exist then. He mentioned that Electrons manifest is fully booked for the next 2 years for dedicated flights. He also doesn’t see a slowdown in demand anytime soon.
Reusability – On the SpaceX front, they have made big inroads to reusability and the Electron is not reusable, so many asked about plans to make a reusable version. The simple answer he gave was that reusability makes sense for medium lift vehicles like the falcon 9, but it doesn’t scale well to small vehicles. So it isn’t on the radar for them at the moment.
Other Rocket Manufacturers – As there are many small rocket manufacturers popping up, and attempting to compete in this space, many wanted to know what the market is actually like for them. His comment was that not all of those manufacturers will make it, and they are currently the only dedicated small launcher that has actually made it to orbit. Others were quick to point out that other rockets of similar size do launch but nowhere near as frequently and do not have the same quality or launch frequency as the Electron.
Where else will they launch from – Currently they have a single launch site, but many wanted to know if they will branch out, to different pads of even different countries, maybe even pad-39A. He mentions that he wants to have many potential launch pads to serve many different inclinations, but Launch Complex 1 is a good start.
Going Bigger – There were lots of questions about making a bigger rocket, like an Electron Heavy. He made a point of saying they are currently only making one product really well. They have no plans to make bigger rockets, and they understand the market they are in. Rocket lab do not want to compete with SpaceX on these launches. He mentions that they can launch a huge amount of spacecraft to LEO, and going bigger only allows a 2% increase in market at the moment. That being said they will continue improving the rocket as they go along.
Using composites – As the LOX tank and other parts are made of carbon composites, there were questions about the difficulty surrounding the design and development of that. He talked about the several years developing and testing the composite tanks. The two main issues being microcracking and oxygen compatibility. They ended up with liner-less tanks with common bulkheads that have similar oxygen compatibility to aluminium but much lighter mass. All the composite manufacturing is in house. Some wanted to know how they manage to use such expensive processes, and he says that although carbon fibre is expensive, when done right you can use very little of it.
Why black – with most rockets out there being white, to help with the thermal efficiency, why did they go for black? Well the simple answer he gave was it looks better. Many engineers wanted to paint it, but the thermal experts made a special effort to make sure they could keep it black. Also, it does save some time/money/weight on paint.
It’s all about the money – The key question is, is it profitable, and when will they start making those profits? Well Peter states that they will see positive cash flow after their 5th flight. Each launch costs $4.9 million to each customer, and they get a dedicated launch, so no need to worry about rideshares where they have less control.
Adding to space junk – In the news recently, there has been lots of the junk that currently floats in space, so there were some questions on how the Electron tries to stop being just more rubbish. Peter talks about the Curie stage of the rocket that is designed to fix this issue. It puts it the second stage into an orbit that makes it deorbit quickly, and the kick stage can deorbit itself. Also most of the LEO payloads they will orbit will deorbit within 5-7 years.
Launch cadence – A few asked how often they are able to launch rockets, or at least the plans to do so. He mentioned that the current plan is to launch once a month for the next year, then once every two weeks, and then double down from there. The Launch complex 1 can support a launch every 72 hours, which is pretty impressive.
Job opportunities – As you would expect, many people asked how you get a job/internship at Rocket Lab. Peter gave a link to email a resume to, but mentioned that the bar is high, they are open to new people but they have to be passionate, and enjoy (and be good at) what they do. They are a small team trying to do big things! They care about what you do outside your formal education, what are you passionate about? what have you built, tested and broken?
Some hardcore technical answers
Each propellant had a dedicated and independent pump system rather than a single electric motor. That was due to wanting super accurate control over the oxygen fuel ratio and startup and shutdown transients.
Ignition is from an augmented spark igniter (a spark plug surrounded by a tube, what acts sort of like a blowtorch).
The engine is fully regeneratively cooled, 3D printed chamber.
The area ratios for the booster and vacuum nozzles are 14 and 100 respectively.
The steering and ullage on the upper stage is controlled by cold gas RCS and PMD.
The whole vehicle is non pyro, the decouplers are all pneumatic.
Although we are a few months into the year I thought I would make a short post about a trip we took just a couple of days into the new year of 2018. With the family and my girlfriend, we set out on a chilly day, with snow still in some shadowy areas, we visited the nearby Stourhead. A very picturesque place, and a nice place to spend an afternoon. Also, there is plenty of history surrounding the place to get stuck into. I took a few photos on my phone, and I thought I would share.
Stourhead is a 2,650-acre estate around the source of the river Stour. It is near Mere in Wiltshire, and contains the village Stourton, extensive gardens, farmland, woodland and a palladian mansion. The estate was owned by the Stourton family for 500 years, until they sold it to Sir Thomas Meres in 1714. The Stourton family has a Peerage associated with it, so there is a Baron Stourton. In 1717 It was sold to Henry Hoare, the son of a wealthy banker, and he demolished the original manor house. Colen Campbell and Nathaniel Ireson designed and built the current house between 1721 and 1725. Over the next 200 years the family collected lots of heirlooms, including a large library and art collection. In 1902 there was a bad fire in the house, but most of the heirlooms were saved. The house was rebuilt almost exactly the same. The son of the final owner, Sir Henry Hugh Arthur Hoare, gave the house and gardens to the National Trust in 1946, a year before he died. His son died at the Battle of Mughar Ridge during World War 1.
Most people got to Stourhead the walk around the lake and gardens. Taking a walk around the lake is meant to evoke a journey based on Aeneas’s descent into the underworld. The buildings and monuments around the lake are in remembrance of family and local history. The style of the garden is meant to be inspired by a painting bought by Henry Hoare, Claude Lorrain’s Aeneas at Delo. The gardens were designed by Henry Hoare II and laid out between 1741 and 1780. The lake was artificially created by damming the small stream. The concept of the small areas with a big monuments is that they invite you over, and then you can see the next one, and that invites you over to that, it is designed to make you want to walk round the garden.
Stourhead, as its name suggests is where the river Stour starts. It is a 61 mile (98km) river which flows through Wiltshire and Dorset, and drains into the English channel. It is sometimes known as the Dorset Stour to distinguish it from the rivers of the same name in Kent, Suffolk and the Midlands. According to Brewer’s Dictionary of Britain & Ireland, the name Stour rhymes with hour and derives from Old English meaning violent, fierce or the fierce one. A large part of the river is followed by the now disused Somerset and Dorset Joint Railway. These trailways are now parts of the Stour Valley Way, a trail that follows the river from the mouth all the way to stourhead, running roughly 64 miles. A number of towns and villages in Dorset are named after the river, including East Stour, West Stour, Stourpaine, Stourton Caundle, Stour Row, Stour Provost, Sturminster Newton, and Sturminster Marshall. Sturminster Newton is famous for a water mill and town bridge which still has a notice warning vandals of penal transportation for those who wish to damage the bridge.
There are some great little facts that come from Stourhead,might be useful for a pub quiz, or just to annoy your friends.
The Temple of Apollo and Palladian Bridge can be seen in the 2005 film Pride & Prejudice, the one starring Keira Knightley.
In the Thunderbird TV series (the original one with the puppets), the model for Lady Penelope Creighton-Ward’s mansion was based off of Stourhead house.
The corporate font for the National Trust font is based on an inscription in the grotto. It was created in 1748 but was accidentally destroyed by mistake in the 1960’s, so the one there now is a replica.
King Alfred’s tower, a folly on the Stourhead estate, was built near Egbert’s stone, where it was said that Alfred the Great, King of Wessex rallied the Saxons in May 878 before the Battle of Edington.
King Alfred’s tower is the start of a 28 mile footpath called the Leland Trail that runs to Ham Hill country park.
On April 2nd, 2018 at 20:30 UTC a Falcon 9 took off from Launch complex 40 at Cape Canaveral AFB. Aboard was a refurbished Dragon capsule with CRS-14, a resupply for the ISS. This was the 14th of up to 20 CRS missions contracted with NASA, with new Crew Dragon variants soon to be used. The capsule safely reached the ISS and was docked 20 minutes earlier than planned. The cost of the mission was reported to be around $2 billion, and comes under a contract between NASA and SpaceX.
The Dragon capsule carried 2,630kg of cargo to the International Space Station, including supplies and research equipment. it has 1070 kg of science equipment, 344 kg of supplies for the crew, 148 kg of vehicle hardware, 49 kg of advanced computer equipment and 99 kg of spacewalking gear. Aboard there are a number of experiments, such as a new satellite designed to test methods of removing space debris. There are also frozen sperm cell samples, a selection of polymers and other materials, all experiments to test what happens to different items when exposed to space and microgravity.
Designated F9-53, the Falcon 9 used booster B1039.2, which previously boosted the CRS-12 mission in August 2017, where it returned to landing zone 1. As is customary, the first stage was left “sooty” from it’s first flight. It powered for 2 minutes and 41 seconds before falling back to earth. For the sixth time in the last 7 Falcon 9 launches, the first stage was purposefully expended, even though it carried landing legs and steering grid fins. As with other expenatures, the rocket went through the re-entry landing sequence, but just didn’t have anything to land on and ended up in the sea. It was the 11th flight of a previously flown Falcon 9 first stage, five of which have been purposefully expended during the second flight, only 3 first stages remain that can be reflown.
The second stage completed its burn at 9 minutes and 11 seconds after takeoff, to insert Dragon into a Low Earth Orbit inclined 51.6 degrees to the equator. The Dragon 10.2 is a refurbished spacecraft capsule that first flew during the CRS-8 mission in April 2016. CRS-14 was the third launch of a previously flown Dragon capsule. This was also the first time that both the Dragon capsule and the Falcon 9 were refurbished versions on the same rocket. The docking process was carried out for around 20 minutes, and at 10:40 UTC Kanai detached the lab’s robotic arm to hook the free-flying Dragon capsule. At around 12:00 UTC Houston and Canada took control of the robotic arm and maneuvered it to the Harmony capsule of the ISS. It will be unpacked in a very slow process over a number of months.
At 14:13 UTC on March 30th 2018, SpaceX launched a Falcon 9 from foggy Vandenberg Air Force Base. Although designated F9-52 this was the 51st Falcon 9 launch. Using a v1.2 variant booster, the rocket delivered 10 Iridium NEXT satellites into orbit. This was the fifth of eight planned Iridium NEXT missions.
From Vandenberg AFB Space Launch Complex 4 East, the first stage of the rocket lasted 2 minutes 34 seconds, separating a few seconds after. The second engine fired for 6 minutes 23 seconds. This part of the webcast was purposefully cut short due to a NOAA remote sensing licensing requirements. This is an issue with SpaceX not having the right licence to broadcast images from certain parts of space. This burn placed the rocket in a roughly 180 x 625 km parking orbit. The Thales Alenia Space satellite then deployed an hour after launch, after a second brief 11 second burn. This put the satellites into a 625km x 86.6 deg orbit.
The rocket used another “Fairing 2.0”, which is slightly larger than usual, but equipped with recovery systems. These systems include thrusters, a guidance system, and a parafoil. The ship, named Mr Steven has a large net to capture the halves of the fairing. Again, the ship failed to catch one of the fairings, due to a parachute system issue. In a tweet by Elon Musk, it was reported that the GPS guided parafoil twisted so the fairing impacted the water at high speed. He also said that SpaceX are doing helicopter drop tests to fix the issue.
Five of the six previously used Falcon 9 vehicles have been fully expended, this was the tenth flight of a previously-flown Falcon 9 first stage. Four of these ten have been purposely expended during their second flight. The first stage (B1041.2) was previously flown during the Iridium NEXT 3 launch on October 9th, 2017. It performed the 2 minute 34 second boost, and performed what SpaceX call a “simulated landing” into the ocean. SpaceX appear to be only launching a reused stages for one reflight, with the soon to launch “block 5” likely to be reused multiple times. Currently the company only have 4 first stages that might be flown, with one allocated for the upcoming CRS-14 dragon resupply mission.