Tag Archives: num:ScienceMuseum=1972-325

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.

Do the maths!

It’s a real privilege to get right up close to an object; being able to read an inscription; noticing the wear and tear; discovering an unexpected little detail. A few years ago I examined the Museum’s Beta 1 – a late 1940s rocket engine – and spotted the letters ‘T STOFF INLET’ inlet stamped on one of the valves.

Beta 1 rocket engine inscription

My discovery on the Beta 1 rocket engine © Science Museum / Science & Society

This British engine was a precursor to those used on the Black Arrow space rocket and I knew of its German ancestry but was still delighted to find clear evidence preserved on the artefact (T Stoff was the German term for hydrogen peroxide oxidiser).

Of course, the problem with many museum objects is that they have to be kept behind glass.

The Apollo 10 command module – one of the Museum’s Centenary icons – is rather fortunately not enclosed but has still to be physically isolated from the visitor with a barrier and from air-born dust by Perspex covers over the hatch and docking port.

Apollo 10 command module, 1969

Apollo 10 command module, 1969 © Science Museum / Science & Society

So for one day only in May of 2009, to commemorate the mission’s 40th anniversary, we sought permission from the spacecraft’s owner – the Smithsonian Institution’s National Air and Space Museum – to VERY CAREFULLY allow people up close to peer inside the spacecraft.

It took a lot of organising, but it was wonderful to see the reactions of the very young visitors who, with help from mum or dad, enjoyed looking in at the truly space age control consoles of the spacecraft.

Computer keyboard, Apollo 10.

Computer keyboard, Apollo 10 © Science Museum / Science & Society

They could just about make out the hurried pencil jottings that the astronauts had made near their computer console. They’d probably been working out some bearings or the timing of a rocket engine burn. As the astronauts say themselves: if you want to be an astronaut you need to work hard at school and do the maths!