Tuesday, 18 July 2017

The British Interplanetary Society - 1940s (Megaroc)

In 1939, with the advent of World War II, the BIS became very inactive; as one would expect!
Of course this didn't stop it's members brains from considering space travel when they got time to themselves. Following the end of the war the Society re-convened in 1945 and very quickly continued with their activities.
A prominent member and future society president, Arthur C. Clarke, published an article entitled 'Extra Terrestrial Relays' in Wireless World magazine.
The first draft of this hugely important article was rather cumbersomely named 'Can Rocket Stations Give Worldwide Radio Coverage?' and can actually be seen in the Smithsonian. From this he is quite rightly considered the ‘conceiver of the geostationary telecommunications satellite’.

Between 1945 and and 1950 the BIS continued to develop and publish important ideas and designs for the future of space travel ranging from Space Stations down to Space Suits and, more feasibly, sending men into space using the technology gleaned from V2 rockets that were captured during the war.

1948 BIS Space Station as designed by Harry Ross and Ralph Smith

The Lunar Space Suit by Harry Ross and Ralph Smith Approx. 1949

The name given to the rocket for use in the sub-orbital flight project that utilised the captured V2 rockets was Megaroc. It was, once again, the brainchild of Harry Ross and Ralph Smith. After Smith surmised that a V2 was ‘nearly big enough to carry a man…’ the pair set to work in 1946 to design a proposal based on these rockets. The proposal was submitted to the British Government in Dec 1946 but was ultimately rejected.

N.B. It is worth noting at this point that the greatest minds in America were also thinking along such lines and there are a large number of similarities between Megaroc and the Mercury project. The American project was much grander however and their ultimate goal was orbital flight.

What if Megaroc had been given the go ahead?

The aim of Megaroc was to carry a man to 304 km above the Earth's surface where studies of the Sun and of the Earth itself would be carried out by the single human occupant.
Megaroc itself was to be a bigger and ‘beefier’ version of the German V2. Although the original rocket motor was to be used, the tank volume was increased and reinforced so as to accommodate more propellant. The motor was to burn at full thrust for nearly 2 mins (110 secs) at 9.8 m/s² and after reaching an altitude of approx. 46,000m it would fire for a further 38 secs at a constant acceleration of around 20m/sec². (The single pilot would be experiencing 3g at this point in comparison to Mercury pilots hitting up to 9g.)

Smith and Ross discussing Megaroc

The jet control vanes at the base of the motor were enlarged and adapted so as to give the rocket a slight roll or ‘spin’ during flight. The stability provided by this meant that the designers could do away with the large and heavy fins at the base of the rocket.

German V2 Rocket

In the image above; where you see the warhead, automatic gyro control and guidebeam and radio command transmitters, a single pilot was seated in a pressurised pod wearing a standard pressurised high-alt flight g-suit. The pod, or capsule, was accessible via a pair of hatches, one each side of a single round viewing porthole. The capsule was to be jettisoned from the hull for safe return to Earth and, for that purpose, a ‘strobo-periscope’ was also included to allow the pilot to view behind themselves after detaching from the main hull.

As the pilot hit 3g they were to manually reduce thrust to keep the g reading constant. In case of emergency where the pilot were to suffer blackouts or be otherwise incapacitated, the thrust control doubled as a dead man's lever, giving ‘ground control’ radio control of the rocket should the pilots grip relax.
Once the atmospheric pressure had reduced to a set point, the nose cone sections would release, leaving the pilot to activate a small pressurized air charge to separate the capsule from the main body of the rocket. On separation a delay timer also kicked in which would deploy the parachute for the rockets hull at the correct time.
The apex of the flight was expected to be achieved at 6 mins and 16 secs, giving the pilot a limited time to make observations and studies at a variety of different g-forces. After aligning the capsule correctly for re-entry, the pilot would then deploy the constant drag parachute at 113 km, the main ‘chute deploying as they approached the Earth and detaching on impact to stop the capsule being pulled along the ground.


Edit: I have since found the following online.

Megaroc Stats:
Hull diameter:                   2.18 m
Length of rocket:              17.5 m
Launch weight:                 21.2 tonnes
Cabin return weight:         586 kg

Other Stats:
Maximum ascent acceleration imposed on pilot:    3 g
Maximum deceleration imposed on pilot:               3.3 g

Launched from a tower inclined at an angle of 2° from the vertical

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