Man in the moon suit
QUESTION Where are the spacesuits worn on Apollo 11?
The spacesuits worn by Neil Armstrong and Buzz Aldrin for their historic moonwalks on July 20 and 21, 1969, can be found at the Smithsonian National Air and Space Museum in Washington, DC.
The suits were miniature space craft in their own right — designated extravehicular Mobility Units (eMUs).
These were highly sophisticated garments which had to protect against space hazards, micrometeoroids and temperatures ranging from -150c to 120c, while allowing mobility and dexterity.
The suits were individually tailored for Armstrong and Aldrin by the International Latex Corporation in Delaware — better known for making bras!
They were made from 21 distinct layers of protective material, the outer layer being tough Tefloncoated fibreglass known as Beta Cloth.
The Apollo 11 eMUs, when attached to their portable life support system (PLSS) weighed 81kg (180lb) or 13.6kg (30 lb) in the reduced gravity of the Moon’s surface.
The astronauts’ overshoes and PLSSs were left on the moon to reduce launch weight but the suits were returned to earth. The eMUs were first displayed at National Air and Space Museum in 1976 but were taken into storage in 2006 when curators became concerned about their deterioration. They were designed to cope with the harshest of environments but not to last half a century on display and there were signs of deterioration in the plastics and rubber seals.
The suits recently underwent an extensive conservation process funded by thousands of public donations. The process involved creating a detailed three-dimensional map of the suits using X-rays, CT scans and UV photography, as well as extensive research into the suit’s manufacture and various functions. Museum conservators worked to preserve the suits, keeping features of historical significance such as the lunar dust and hand-made repairs made before flight. Neil Armstrong’s suit went on public display on the 50th anniversary of the moon landing. It remains on display in a climatecontrolled case that monitors temperature, lighting, humidity and ventilation. Buzz Aldrin’s suit is currently undergoing a similar restoration. Alan Gould, Nantwich, Cheshire.
QUESTION Why are backless shoes called mules?
ThIS word has surprisingly ancient origins — which has nothing to do with donkeys or horses. Mules or slippers arose in the Middle east and were favoured by egyptians, Greeks and Romans. In Ancient Rome, the phrase ‘mulleus calceus’ was used to describe the red or purple shoe worn by Roman Patricians. Calceus was the Roman word for ‘boot’, whereas mulleus is thought to derive from mullus, a red mullet, a fish, referring to the colour. Mules, known as pantofles, were adopted by French women by the 16th century as bedroom slippers. By the end of the 17th century, wealthy French women were wearing sexy high-heeled, highly adorned mules in public — a tradition continued by the likes of Mamie Van Doren and Marilyn Monroe in the 20th century. Bea Morris, Charlbury, Oxon.
QUESTION Why were 78/45/33 rpm used as the standards for vinyl recordings?
The speed of 78rpm for early shellac records was based on the mechanics of the time.
When record turntables were first driven electrically, a 3,600rpm motor was used, which, when geared to drive a turntable, resulted in a speed of 78.26rpm (at a mains frequency of 60 hz; at the UK mains frequency of 50 hz the speed becomes 77.92 rpm). So the term ‘78’ was just a nominal speed.
In 1931, 331/3rpm records were introduced. As today, there has always been a desire for improving the sound-quality of recordings. This became possible with the development of poly vinyl chloride, or PVC from which the term ‘vinyl records’ comes.
And because PVC is made of smaller particles than shellac, it became possible to reduce the groove-width, thereby giving better quality audio.
So why 331/3 rpm? Well almost certainly this speed was derived from an earlier speed of turntable used in the film industry. With the development of the ‘talkies’ in 1927, the audio soundtrack was not, as today, on a magnetic strip on the film footage but on large shellac discs that were mechanically driven on a turntable from the film projector via a driveshaft and gearbox, the resultant speed of these turntables was 16 2/3 rpm.
The sound was synchronised with the action on the screen. The sound quality was poor by today’s standards, but perfectly acceptable for dialogue.
In an effort to achieve better soundquality, with the development of the micro-groove 12in PVC record, logic dictates this speed was doubled and became 33 1/3 rpm ... simple really!
The 45rpm record followed in 1949, as different manufactures were trying to develop their own unique medium, hoping it would become the standard. As such, 45 rpm 7in discs were developed by RCA as a rival to Columbia Records’ 33 1/3 rpm Long Play record.
A faster higher playing speed gave it the theoretical advantage of having better sound quality, thus 45rpm was purposely chosen to that end.
But initially these 45s did not catch on because of their shorter playing time.
Meanwhile, juke-box manufactures were looking for a more compact medium than shellac 78s, with the ability to load more discs on board — and the 45 was an ideal choice, a concept they embraced heartily and quickly. Wallace (EARS) Aitchison, retired sound engineer,
Truro, Cornwall.