Author Archives: Doug Millard, Space Curator

Sound Advice

I set out to the National Physical Laboratory the other day and on my way down Exhibition Road passed an elephant.

Elephant Family appeal, Exhibition Road

Elephant Family appeal, Exhibition Road, 2010 (Doug Millard)

Some 250 of these colourful models are being positioned across London to raise awareness and funds for the plight of their living cousins. A little later something niggled at the back of my mind – as though that elephant was trying to tell me something – but I thought no more of it and caught a train for Teddington and the NPL.

This, I’m ashamed to say, was my first visit to the Laboratory, also known as the National Measurement Institute, where, for over a century, physical standards have been measured, studied, applied or all three.

Scientists at the NPL, 1932

Scientists at the NPL, 1932 (Science Museum/Science & Society)

It was International Metrology Day, May 20th - exactly 135 years since seventeen nations agreed to the metre as the fundamental unit of length. The original Metre, made from platinum and iridium, is housed in Paris but the NPL has one of the carefully guarded official copies. These days a Metre is defined by the distance light travels in a vacuum during 1/299 792 458 of a second.

NPL also does a lot on sound - acoustics - and I was particularly impressed by the Laboratory’s anechoic chambers.

Science of Acoustics, 1850

Science of Acoustics, 1850 (Science Museum/Science & Society)

Now, while the Science Museum has all sorts of acoustics objects and pictures in its collections it has nothing like the NPL’s rather fearsome looking chambers where sounds produce no echo; here’s a link to one of the NPL’s anechoic chambers in action.

NPL Anechoic Chamber, 2010

NPL Anechoic Chamber, 2010 (Crown)

The NPL studies all manner of sounds, those the human ear can readily detect but also those at too high a frequency for us to hear – ultrasonic – or too low – infrasonic. Other animals are different, though: elephants, for example, have been shown to communicate using really low frequencies. Scientists suggest that this allows them to coordinate their own movements over distances of many kilometres. Maybe the Exhibition Road elephant was trying to tell me something earlier that day.

The goodness of wood

I stumbled across an old Monty Python sketch the other day that plays with words pleasing to the ear (‘woody’) or displeasing (‘tinny’). I chortled (nice woody word) but then started thinking about wood and science - we don’t often associate the two and we’re culturally conditioned to associate wood with words like ‘old’:

Roe Triplane at Lea Marshes, 1909

Roe Triplane at Lea Marshes, 1909 (Science Museum/Science & Society)

and ‘amateur’;

Man Sawing Wood, 1997

Man Sawing Wood, 1997 (Science Museum/Science & society)

But appearances can be deceptive as the Mosquito aircraft demonstrated. It may have resembled its alloy contemporaries of World War 2 but its sleek exterior cloaked a strong, lightweight structure of balsa, birch and spruce.

And the very obviously metallic masts and aerials of Rugby Radio Station, long standing landmark twixt the A5 and M1, relied on a hidden, cathedral of wood – the Linden or Lime Wood-supporting structure for the transmitter’s tuning coil assembly.

Rugby Radio Station’s Very Low Frequency Tuning Coil Assembly, 2004

Rugby Radio Station’s Very Low Frequency Tuning Coil Assembly, 2004, (Science Museum).

And lest we think of the space age as an era of quintessentially expensive and exotic materials we should remember that Apollo astronauts needed cork to get to the Moon (it lined the boost protective cover that protected their command module and windows should the launch escape system be used),

Apollo Launch Escape System, 1968

Apollo Launch Escape System, 1968 (NASA)

and that China’s Fanhui Shei Weixing reconnaissance satellite had oak in its heat shield to help it ablate (burn away and dissipate the heat of atmospheric re-entry).

England expects…

London is the space insurance capital of the world. If you have a £150m satellite to cover then you’ll probably end up talking to an underwriter based at Lloyd’s in the City.

I was mulling this over as I gazed up at Nelson on top of his column in Trafalgar Square the other day - I’d been taking a small detour to see what was going on in Downing Street – it was the morning after the general election.

Nelson's Column, Trafalgar Square, under construction, April 1844

Nelson's Column, Trafalgar Square, under construction, April 1844 (Science & Society)

As I walked on down Whitehall I thought of the words I had read on the floor of Lloyds just two days earlier: ‘England Expects that every man will do his duty’. This immortal prose - a signal sent by Nelson just before the Battle of Trafalgar - is preserved in the logbook of HMS Euryalus, an observing, non-combatant ship now displayed amongst Lloyd’s Nelson Collection.

Nelson’s flagship communicated to the fleet by a system of semaphore flags hoisted from its masts. It is likely (does anyone know for sure?) that related messages, once reaching land, were hastened to the Admiralty via semaphore towers that stretched from Portsmouth to London. I’m old enough to remember the working model of a similar ‘Chappe’ tower in the Science Museum’s old Children’s Gallery.

Children's Gallery and model of Chappe Telegraph, 1954

Children's Gallery and model of Chappe Telegraph, 1954 (Science Museum/SSPL)

Times moved on and optical telegraph gave way to electrical and then radio.

Today the armed forces use satellites with the Skynet series another of the UK’s unsung space technology successes. But such military spacecraft are not insured at Lloyds: the government (i.e. the tax-payer) picks up the bill should anything go wrong!

Up in the air?

Recently I received an email alerting me to the launch of the United States Air Force’s X-37B spaceplane, a winged, unmanned mini-shuttle capable of reaching orbit and then returning autonomously to Earth.

Earlier that day I had been looking at 1960s military wave rider wind-tunnel models at the Science Museum’s main store.

Two waverider wind tunnel configurations trailing pressure sensor cables

Two waverider wind tunnel configurations trailing pressure sensor cables (V. Carroll)

A wave rider is a particular design of aerodynamic wing – for planes and missiles travelling at hypersonic speeds (at least five times the speed of sound) – in which air trapped beneath the vehicle’s underside actually enhances its performance (no classroom jokes, please).

Problem is, such designs – some were incorporated in the massive XB-70 ‘Valkyrie’ bomber, have never really worked that well.

XB-70A bomber used some wave rider features, 1965 (NASA)

Sunday’s paper carried another story, this time about the launch of the United States Defence Advanced Research Project’s Agency’s (DARPA) HTV-2 or Hypersonic Test Vehicle-2:  an unmanned, rocket-launched, manoeuvrable, hypersonic air vehicle that glides through the Earth’s atmosphere at incredibly fast speeds—up to Mach 20.

On the way home last night I dipped into David Edgerton’s ‘The Shock of the Old’ in which he suggests that some of today’s aerospace technologies are little changed from those of forty and fifty years ago… and still not all they are made out to be.

I expect the latest launches from the USAF and DARPA will also fizzle and pop towards cancellation, like many of their predecessors, their high velocity achievements still only inching us forward at incrementally slow rates.

But, if the novel technologies touted – aerodynamic shape… thermal protection structures… autonomous hypersonic navigation guidance and control systems… prove  truly effective then, just perhaps, we are about to enter a new era of prompt global reach and swift access to space with all the implications that holds.

What’s in a name?

What’s in a name? I ask with the new ‘United Kingdom Space Agency’ in mind. The ‘muscular’ new space agency was launched with a new punchy logo but, I fear, a rather weak name. We might shorten it to something pronounced UK-SAR or perhaps to a simple abbreviation reading YOO-KAY-ESS-AY.

Back in the 60s a fair chunk of UK space research was carried out at the Royal Aircraft Establishment (RAE – pronounced AR-AY-EE) in Farnborough, Hampshire.

The Science Museum has many examples of the Establishment’s experimental work, which extended well beyond space endeavours like the Skylark rocket:

Skylark rocket launch

Skylark rocket launch (Science & Society)

To aviation research including the Concorde project and high altitude suiting:

Upper half of partial-pressure suit, ca. 1954

Upper half of partial-pressure suit, ca. 1954 (Science Museum/Science & Society)

And on to breakthrough technologies, like the strengthening of carbon fibre:

Oven for making carbon fibre, ca. mid 1960s

Oven for making carbon fibre, ca. mid 1960s (Science Museum/Science & Society)

But back to the RAE name itself, which substituted ‘Air’ with ‘Aerospace’ in 1988 then, as rationalisation and privatisation beckoned, ditched the whole caboodle in favour of DRA (Defence Research Agency), DERA (Defence Evaluation Research Agency) and finally to the present post-privatisation forms of QinetiQ – the company – and DSTL (Defence Science and Technology Laboratory) – a government agency… which brings us back to UKSA.

On April 1st 2010 UKSA takes over from BNSC (British National Space Centre) which had been coordinating the UK’s various space activities for over 25 years. Some say it was doomed because it lacked a dedicated budget or executive powers, but I suspect the main reason it was finally killed off was its lack of vowels: BNSC - try making a memorable acronym out of that…

Whereas NASA – whoa! Consonant-vowel-consonant-vowel, guaranteed to stick in the mind. That’s really how America got to the Moon – by perfecting the art of abbreviating and acronyming. They made a science of it.

Will UKSA achieve the same? Best ask how the following got on with the same letters: United Kingdom Sailing Academy; United Kingdom Skateboarding Academy and United Kingdom & Irish Samba Association … and there’s plenty more where these came from.

Clean eyes, clean rockets

So, what’s the connection between contact lenses and rocket engines? The answer, I probably don’t hear you cry, is hydrogen peroxide and cleanliness.

Blown glass contact lens, 1930s (Science useum/Science & Society)

You see, to clean my newly acquired contacts involves bathing them overnight in a solution of hydrogen peroxide. Peroxide is a pretty powerful chemical agent and disinfects the lenses in 6 hours. If you put your lenses in too soon the still active chemical will turn on your eyeballs and cause them to gush tears like Gordon Ramsay’s head onion peeler. After six hours, though, the peroxide is decomposed and all you are left with is clean and lifeless water.

The lens holder includes a small piece of material (I have yet to identify it) that catalyses the decomposition of the peroxide solution. If it didn’t then the peroxide would remain and, having successfully killed the bugs on your lenses, then do its best to kill the cells of your cornea too. And this is where the rocket engine connection comes in.

The reaction that decomposes the peroxide also produces oxygen – you can see it bubbling off the catalytic material. That same type of reaction, albeit using extremely concentrated hydrogen peroxide, was exploited in the engines of Britain’s Black Arrow space rocket to launch the Prospero satellite into orbit in 1971.

Uprated Black Arrow rocket engine, c. 1970 (Science Museum/Science & Society)

The catalyst used was silver metal gauze and it decomposed the peroxide violently into oxygen and steam, which then ignited kerosene fuel, and so provided thrust to lift the rocket. In fact, earlier rocket engines dispensed with fuel altogether and replied on the thrust of the decomposing peroxide alone.

Oh, and the cleanliness connection? Well, peroxide rocket engines are considered ‘clean’ or green as their exhaust, after all, contains little more than oxygen and steam.

The show must go on

I had decided to write a few lines on a Museum object called Silverbird. On a whim I asked Wikipedia to show me what it could find and I was delighted to learn also of a similarly named passerine bird native to Eastern Africa, a former software label of BT from the mid 1980s and even Leo Sayer’s debut album.

Science Museum’s scale model of Silbervogel

Science Museum’s scale model of Silbervogel. (Science Museum)

Despite such tempting distractions I decided to stick with my Silverbird, or the more accurately named Silbervogel, the Museum’s scale model of a 1930s winged and rocket-propelled, sub-orbital bomber that was designed to climb into space, glide back through the atmosphere and drop its deadly payload on the enemy.

Silbervogel had been the brainchild of Eugen Sanger while a research student in Vienna. He went on to work for the Luftwaffe and in post-war years for the French Air Ministry before returning to Germany to continue his pioneering aerospace research. Just the other day his son popped into the Museum to be filmed alongside the model.

American test pilots by the HL-10 Lifting Body aircraft. (NASA/Science Museum)

American test pilots by the HL-10 Lifting Body aircraft. (NASA/Science Museum)

Silbervogel never flew, but it did influence aviation and space projects during the 1950s and 1960s, including the X-15 rocket plane, the Lifting Body aircraft configuration and the early research on what became the US Space Shuttle. That’s why the Museum’s workshops constructed our model: to provide some historical context to the old Exploration of Space gallery’s Shuttle display case.

First launch of the Shuttle, 1981 (NASA/Science Museum)

First launch of the Shuttle, 1981 (NASA/Science Museum)

Of course, the Shuttle programme itself is now nearing the end of its life and with President Obama cancelling NASA’s plans to go back to the moon it is far from clear where the US will aim for next in space. Leo Sayer’s next song on his Silverbird album is The Show Must Go On. But it’s by no means clear that it will.