Mars Rocket

 

 

The most detailed plan is the one described here by Space X. NASA have the more immediate lunar return as objective with a Mars mission perhaps in the 2030’s. As previously noted Space X is the private company controlled by Elon Musk, a visionary scientist and entrepreneur. Elon Musk is a wealthy man but Space X also part finances itself by supplying various space services and by raising outside finance. Although NASA has separate Mars plans they also co-operate with Space X

The declared objective of Musk is to make mankind an interplanetary species. He envisages a human colony on Mars. The timescale is flexible as the Mars rocket is in early development but the target is unmanned launch to Mars in 2026. Launch opportunities for low energy transfer occur approximately every 2 years and the earlier date of 2024 Musk now feels is probably too early.

The Space X Mars rocket has rather confusing nomenclature. The part which will travel to Mars is called Starship but this is the upper stage of a two stage launch vehicle also called Starship for both stages, The lower initial stage is known as Super heavy booster.

At the time of writing in Feb 21 Starship is conducting low altitude test flights and several Starships are under construction while the booster has never flown.

The total Starship as it will be launched is massive. It is 9m in diameter with booster stage 72m tall and upper ( Starship ) stage 30m tall. It is about the same height as the Saturn V Apollo lunar rocket but much larger and heavier. A guessestimate of the launch weight is 5000+ tons.

A new rocket engine has been developed called Raptor. This engine is designed to be as efficient as possible using so called full flow staged combustion. Essentially this means that the engine turbo pumps burn the main fuel and exhaust through the main engine bell. This contrasts with many earlier engines where the turbopump exhaust is dumped without much contribution to thrust. Starship will have 6 Raptor engines, the booster 28. 3 of the Starship engines will be optimised for best efficiency in the vacuum of space. The engines burn liquid methane as fuel and liquid oxygen as oxidiser.

This number of engines in the booster generates such intense sound that it will be launched from an offshore platform. This will be based on a heavily modified oil exploration platform. Early Starship test flights are from near the assembly factory at Boca Chica in Texas. They are unladen and use fewer engines.

The general plan is for the combination to launch from earth, the booster stage will burn all its fuel and then the Starship will fly on to orbit. At that stage Starship will have used almost all its fuel and will be refilled by a tanker Starship flying from Earth. Thus replenished Starship can accelerate to escape velocity and head to Mars. On reaching the very thin Martian atmosphere it will be slowed by first frictional heating , then a hypersonic parachute and finally by using its engines to land. On Mars it will refuel using the carbon dioxide atmosphere and water to produce fuel and oxygen from plant previously deposited by unmanned missions. Starship will then launch, fly back to earth, re-enter earths atmosphere and finally land under propulsive power.

The re-entry phases will be by the Starship horizontal with respect to the ground turning vertical in the final stage to allow propulsive landing. This is intended to give the highest drag on atmospheric re-entry. The bottom of the Starship will be covered by ceramic tiles to withstand the intense heat as the atmosphere is entered.

The Starship has a pressurised area at the top to accommodate up to 40 passengers. They will have individual cubicles in addition to common room, exercise area and viewing area.

While much of this is the plan which may well change as development proceeds Space X is a serious company with a good track record, Their workhorse Falcon 9 has something like 120 successful flights. It has been chosen by NASA along with its Dragon spacecraft to transport astronauts to the International Space Station. The Dragon sits atop the Falcon 9.

The Starship will be modified for lunar landing. The Moon would be too dusty for normal propulsive landing so the proposed modification has additional rockets mounted higher. Because of its size some sort of elevator is planned to deliver astronauts to the lunar surface from their position near the top of Starship.

Lab builder

 

 

Looking back at my career I’ve worked either for large companies ( Unilever, Castrol ) or very small ones ( 15-20 people ) Large companies are well resourced and offer things like travel and training opportunities more easily. On the other hand they require a degree of specialisation and the individual lacks autonomy. After I suffered a stroke I was very pleased to be in a large company that could pay me for the 7 months I was absent.

A small company is quite different. Your individual contribution is clear, it is less bureaucratic, and you are expected to be much more self reliant.

When I joined Techtron, a small West Midlands company, I expected the small company ethos but I wasn’t quite prepared for starting the technical department by building my own laboratory. I was allocated a large empty room in a newly leased warehouse. I was provided with a desk and filing cupboard.  Electricity and water supplies were fitted by professionals but thereafter I was on my own.

I soon decided the way forward was to fit out with self assembly kitchen furniture. This provided the type of storage and resistant work surface I needed. I didn’t intend to handle very noxious materials so things like fume hoods and extra ventilation were not required. The room was surrounded by half height windows so the safety issue of working alone was covered by the two warehouse staff who had their office immediately adjoining.

Once I had a plan actually building the units was fairly simple. A couple of weekends sufficed. I had access to a local equipment supplier and materials were often scrounged from chemical suppliers. The products we sold were made under contract and these companies felt obliged to be quite helpful. I didn’t have a specific equipment budget but I bought basic equipment to enable product development. I couldn’t have afforded anything but the most basic scientific instruments so for anything elaborate I had to go outside, scrounging if possible, paying if not. I made “guest” appearances at previous employers on some occasions to use particular apparatus. In at least one case I caused a senior manager to do a double take on seeing me commenting “but I thought you had left”. Fortunately he didn’t enquire too closely into my reason for visiting.

Although not that long ago I didn’t have a computer initially. This was in the days of the IBM compatible, MS-DOS machines. I recall scrounging software for it and then being told off later for not having proper licences. I had just started to do some real work using a Lotus 123 clone called As easy.. as before I left.

Access to scientific literature was by Birmingham Central Library. They lacked everything but the most common scientific journals but I mostly needed fairly standard reference works which they had. I didn’t have borrowing status but I photocopied what I needed. I did have to buy some very specific works on regulations etc from HMSO because I needed them on my desk for immediate reference.

I did need to, very occasionally, buy in specific expertise. For example when I needed metallurgical examination of some aluminium truck wheels which  we had been accused of corroding we sought Sheffield University’s metallurgical evidence. When they affirmed as an independent source that we were not to blame we avoided potentially costly damages and retained an important customer.

I had a very good relationship with guys in the warehouse. I think they regarded me as a great curiosity and didn’t hesitate to play practical jokes on me. The most elaborate was after an incident where my “ magic” mug had been accidentally broken. Incidentally the magic was that it changed colour according to the temperature of the contents. I was rather grumpy about this as I much valued the mug. Some days later there was another crash outside the lab followed by plenty of exclamations and oaths. On dashing to find out the problem I found another mug of mine in pieces on the floor. Just as I was winding up to a tantrum I saw I was being laughed at. On inspection the broken mug turned out to be the original which had been stuck together again.

This prankster was something of a ladies man. He was in his sixties but rather tall and distinguished looking. One snowy day seeing a lost young lady outside he asked her in for a cup of tea. It was my habit to break up the day by doing small jobs around the warehouse. This day I was sweeping the snow off the entrance ramp. The young lady asked if I wasn’t to be invited in to take tea out of the cold. The prankster grandly said” Don’t worry about him , he's only the snow shifter”.

The young lady, Philomena, thereafter used to call on us for a tea break and she then found I was the technical manager. She used to entertain us with stories from her sales rep life. Her boy friend was a naval officer and we heard accounts of attending naval events some of which sounded rather grand.

Rocket

 

 

I’ve written the following as part of a general knowledge program for my grandchildren. Although they are working online with their schools I thought they would benefit from something entirely different. I’ve been interested in rockets and space travel all my life so the launch procedure is well known to me but it may not be apparent to the casual reader. When I was a teenager I joined the British Interplanetary Society. At that time in the late 50’s this tended to be seen as a society of cranks and weirdos .although in fact it is a fairly sober scientific group. By that time with the launch of the first space satellites it was just about gaining public credibility. This didn’t stop the Astronomer Royal of slightly earlier declaring that “space travel is bunk”. I did go to one meeting in Birmingham which described a very futuristic mission using fusion power derived from helium three. I was slightly embarrassed to ask a question in which I didn’t properly aspirate the h in helium.

In a fit of economising after I married I dropped my membership in 1965. Ironically this was just as the tempo of development culminating in the Apollo moon missions was ramping up. After just starting work I was too busy to follow all the detail although I retained my interest.

Many different types of rockets have been flown. The largest ever so far was the Saturn V for the Apollo moon missions fifty years ago. At take off this weighed about 4000 tons. To describe a rocket used a lot nowadays I have picked  the Falcon 9 by Space X. Although not entirely typical it is the most used currently.. All rockets work on the same principle. They hurl mass out very fast and by Newtons  law that reaction equals action the rocket moves in the opposite direction. The energy required to hurl out the mass is from the burning of chemical fuels. The fuel used is rocket grade kerosene and the oxidiser is liquid oxygen. The fuel consumption is very high and rocket engines burn at the rate of many tons of fuel per minute but for a short time, only a very few minutes.

It is usual for the rocket to work in stages. Thus a first stage burns all its fuel then drops away reducing the weight of the whole. Then a second stage until it to drops way and so on In this way the least weight is carried to orbit.. The Falcon 9 has two stages.

The Falcon 9 apparently gets its name from the Millennium Falcon in Star Wars followed by 9 which is its number of rocket engines. The idea is that rocket engines can fail so the remainder burn for a bit longer to compensate.

It is expensive to build complete rockets and then throw most away after staging. The Falcon 9 pioneered the recovery of the first stage for re-use., a concept which is now widely accepted. After the first stage has completed its burn it retains just enough fuel to return to earth and land.( You can watch this on Youtube ; the best view of landings is with Falcon Heavy which is 3 Falcon 9 linked together )

The Falcon 9 is big; In metres 70 tall and a cylinder of 3.7m diameter. Loaded at take off it weighs about 550 tons. Of this height the first stage occupies about three quarters. The rocket most often serves to launch  satellites. Theses satellites are housed in a fairing at a nose of the rocket. The fairing is needed to shield the payload ( satellites ) from aerodynamic forces as it accelerates through the thick lower atmosphere. These aerodynamic forces are substantial as the rocket goes supersonic ( faster than the speed of sound)

The launch sequence is roughly as follows. The engines are ignited and run for a second or so to spin up the turbopumps transferring fuel to the engines. These pumps move the fuel and oxygen very fast at a rate of many tons a minute. A rocket does not use any oxygen from the air; it carries its own on board , often in the form of liquid oxygen which is very. very cold. While the engines are starting and building up thrust the rocket is held down.

If the engines are all working properly  which is checked by computer control, the rocket hold downs are released and the rocket takes off rising vertically before gradually turning over until at very high altitude it is parallel to the earths surface. As it rises if one engine fails then the others burn slightly longer to compensate. The rocket balance is maintained by slightly altering the direction of thrust by the engines. The engines are attached by flexible mounts( gimbals) which allow this movement under electronic control.

As it rises most of the fuel in the first stage is used up and the first stage is separated  and falls back to earth under radio control to direct it back to the desired landing place. Its direction of fall is controlled by  small wings called grid fins. As it falls it first fires its engines to slow down( it’s travelling very fast ) and then just above the ground it fires its engines again and splays out landing legs held against the side of the rocket and lands.

Meantime the second stage has fired its single engine ( it only needs one being much lighter and in thinner air ) and also the fairing around the payload is jettisoned. An effort is made to recover the fairing halves but this is only sometimes successful at this time. The second stage then ascends to orbit attaining a speed of about 17000 miles per hour when the satellite separates. The second stage is also in orbit..

The whole launch process takes 6-7 minutes to orbital height and speed but the manoeuvring to achieve the precisely desired orbit can take longer. Satellites can have small engines to do this. Big orbit changes may occur before separation using the second stage engine to make multiple burns.

The payload depends on the orbit desired and many other factors but is of the order of 5 tons. As can be seen the orbital payload weight is of the order of 1% of the rocket at take off

The biggest ultrasonic cleaning tank in the world

  

I was commissioned by Castrol to visit Kerry Ultrasonics and advise on products for use cleaning rescued artefacts from a sunken ship Mary Rose. I had the pleasant feeling of being off the leash as I bowled along in our new pool car, a Rover 2600. As Kerry was also owned by our parent Burmah I wasn’t even meeting a minder. Castrol had the attitude that technical staff were totally naïve in the ways of the world, should never be allowed with customers on their own, and were always to be accompanied by a minder. This had its attractive side as they were expected to entertain you, translate , arrange accommodation and the like.

It was a pleasant spring day and an enjoyable trip. I arrived to be met by a slightly worried looking guy who said their MD wanted to see me when I arrived. Aha I thought, a pleasantly formal greeting, possibly a gentle chat over a cup of tea. I had grown used to being treated with a great deal of respect when I made visits.

I duly presented myself to Gordon the MD, a short ,choleric man who greeted me as I  entered ”So you’re another of these useless wankers from Castrol”. I was absolutely gobsmacked as I was subjected to a quarter hour rant to the effect that we were a bunch of overpaid, idle, self abusers who couldn’t be expected to be of the slightest use.. As he wound down he could see that I was totally flummoxed and by degrees he explained in a more kindly way that I was to have the problem explained by the minion I had met and I was then to present myself again in a week’s time with the answer to their needs

I duly met with said minion and things became somewhat clearer. The “Mary Rose” was a 16^th century warship  ( Henry VIII’s flagship ) which sank in the Solent in 1545 and had recently been recovered along with a great many artefacts from the period. The recovery operation had Prince Charles as patron who had turned to Margaret Thatcher, the then Prime Minister for help in finding supporters. She in turn had talked to her husband Denis Thatcher who was a director of Burmah. In turn he had talked to Gordon. Gordon had expansively said they would donate an ultrasonic cleaning tank to the conservation operation having in mind a typical small tank.

Now ultrasonic cleaning tanks were typically quite small, twenty litres quite normal and a hundred litres would be quite substantial. However the conservation operation had recovered a number of large wooden gun carriages and needed a tank which could accommodate these. This meant a tank of 2000 litre capacity. This was a very expensive, unique piece of kit which Gordon now felt committed to donating despite his unhappiness at the cost.

I was also to find another reason for his jaundiced attitude to Castrol. Years previously ( before my time ) Castrol had become somewhat persuaded that ultrasonic cleaning was the future. A series of products had been cobbled together without much thought and with very little success. Nevertheless Kerry had become obligated to try and sell these products which they came to regard as a millstone around their necks..

Fortunately I could easily understand the immediate technical problem and was able in a week to revisit with an acceptable product. Castrol was donating the product to the “Mary Rose” trust. It was pleasant that the development was quick and easy as we didn’t even have our own tank to test.

To digress we later bought one which became extremely useful on open days. We did a demonstration of jewellery cleaning particularly rings. It was always gratifying to see the amount of accumulated crud removed in seconds. Our joking introduction always was along the lines that any jewels removed and falling to the bottom of the tank were ours. None ever were, of course. Rings, particularly complex ones, collect a lot of dirt and dead skin cells.

The Kerry test was in a way very simple. The product solution filled the test tank and it had to “couple” as the jargon had it- that is it had to wet the ultrasonic transducer and travel through the solution to the item to be cleaned. Success was indicated by a steady  hiss, failure by a horrible screech varying  randomly in pitch.  Successful transmission shredded aluminium foil.

I was to spend an interesting day visiting the warehouse storing the artefacts from the ship. The wood had become complete soaked in seawater with iron salts deposited in the wood fibres. Drying was disastrous and conservation required the iron salts and water to be removed and replaced by a thick liquid such as a type of antifreeze. Drying alone just gave a distorted and unstable residue as a lot of the internal structure of the wood had rotted over the years.

Although very interesting it was 250  miles from home at Wilmslow to Portsmouth where the Trust was based and I attempted this in a one very long day. I remember taking a break south of Oxford in late evening and thinking, with sinking heart, only another 150 miles to go. The pool car wasn’t available and I had to use my own.

I was too junior to go to the formal handover ceremony. I was told that there was a horrible few seconds of screeching before the monster tank settled down to a steady hiss to the profound relief of the Castrol dignitaries present.

I later became quite friendly with Kerry staff who allowed me some rare privileges.  However I never forgot the shock of my introduction.. I also learned that the technology Kerry used ( Piezoelectric) was unsuitable for large tanks and the people who did make larger tanks in the US used magnetostrictrive technology