Posts Tagged ‘Hang-Gliders’

Personal Hobby Rocket Based on NASA Mercury Capsule

June 27, 2020

A little while ago I put up a piece about a paper I had published several years ago in the Journal of the British Interplanetary Society (JBIS). This argued that as flying enthusiasts now attempt to recreate the experience of the great pioneering age of aviation by flying hang-gliders and microlight aircraft, so there is an opportunity for developing personal leisure rockets to take space enthusiasts on very short rocket trips in order to recreate some of the experience of real spaceflight. The rockets and the capsules don’t have to be very large – just enough to carry a single person or so to a height of a few thousand feet.

The problem I found when I was going through the equations for just such a vehicle is that the amount of fuel needed would make a rocket that was actually smaller than the capsule for the hobby ‘astronaut’. It would simply be impossible to follow the conventional rocket design in which the capsule stands atop the rocket, as it would simply overbalance. A few years ago I found a couple of videos from the Danish company, Copenhagen Suborbitals, who were also trying to develop their own, private spacecraft. They seemed to be trying to solve the problem by placing the rocket in front of the personnel capsule, like the arrangement of the escape tower on the manned NASA rockets – Mercury, Gemini and Apollo, which preceded the spaceshuttle.

I think the Mercury rocket would actually make a fitting design for such a small hobby rocket. They were the first American rockets which took men into space, after a series of unmanned, automated tests and then using chimpanzees. The capsules were small, designed for only one man, measuring 2 meters in diameter at their widest point, and about 3 meters tall, not counting the escape tower. The rocket that was initially used for them was the Redstone, and it was a Mercury-Redstone combination that took John Glenn in Friendship 7 on his epoch flight into space. This was a suborbital flight from one side of America to the other.

Mercury Restone rocket from The Space Traveller’s Handbook, Michael Freeman (London: Hamlyn 1979) 54.

Obviously, you don’t want a rocket as powerful as a Redstone, as even a suborbital, transcontinental trip would be too far. You’d only need an arrangement like the Mercury capsule and its escape tower. The escape towers on all the NASA manned rockets supported small, solid fuel rocket motors. If there was a problem with launch rocket, they were designed to carry the capsule to safety. Thus they were developed to take crewed capsules on the kind of very short trips of the kind that a crewed hobby rocket may also make.

Mercury capsule from the above book, page 56.

As a hobby rocket would not actually travel beyond the Earth’s atmosphere, it would not need retro-rockets and heat shield. It would still obviously need to carry a parachute, which would also still need to be above the rest of the capsule for the safety and stability of the hobby astronaut. I’m thinking of short trips that go up and straight down, with the capsule landing on its base. From the above illustrations it looks like the escape tower rocket minus its aerodynamic spike was 172 cm long and 43 cm wide. Looked at closely, it also seems that it had three nozzles arranged at equal spaces around its base, angled away from the body of the capsule to provide thrust while maintaining stability.

In addition to the problem of stability, the escape tower arrangement also poses some difficulty in that in order for the parachutes to open, the escape rocket itself must be jettisoned. This complicates the design of capsule. It struck me, however, that this could be solved if the single escape rocket was replaced by three solid rockets 572 cm long at the rear of the capsule, spaced at equal distances around its circumference in order to provide stability as shown in my sketch below.

If the rockets and their exhaust nozzles aren’t able to support the weight of the capsule, perhaps landing legs somewhat like those of the lunar module the Apollo astronauts used to land on the Moon could be added.

I’m not a rocket scientist, just an ordinary person who has read some of the science and physics involved, so don’t take this as solid fact. But I think the three rockets together would provide the same amount of thrust as a single rocket of three times the length of one of them. However, as the three rockets would fire together, the actual burn time would be shorter and so imagine it would ascend with a greater acceleration than a single, larger rocket would. But the speed reached, and thus the height after the rockets stopped firing, should be the same.

I think the design’s practical, though it would obviously have to undergo extremely rigorous tests before any aspiring hobby astronaut got anywhere near it. However, there is already a large hobby rocketry milieu. They largely fire off models rockets, but these can be quite large. One group of enthusiasts, according to the magazine High Power Rocketry, sent up a Minuteman missile one year. And last year an American built his own steam rocket which successfully took him a mile up. The man was an eccentric – he wanted to make the journey as he really believed the world was flat and wanted to see if it was round. But his rocket worked, although he lost his life making a subsequent flight. And if one man wants to make an amateur, hobby rocket flight, there are probably others. This is an idea waiting to be developed by professional aerospace technicians and engineers.

But if successful, it would create a new age of personal rocketry and interest and enthusiasm for real spaceflight, just like those flying hang-gliders and microlights are enthusiastic about conventional aircraft.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

My JBIS Paper on Passenger-Rated Hobby Rockets

October 16, 2018

After the flight a few months ago of the American eccentric in his steam-powered rocket to see if the Earth really was flat, and Richard Branson’s announcement last week that he was only weeks away from sending his first tourists into space aboard his Virgin Galactic spaceplane, I thought it was time I put up a piece about a paper I had published in the Journal of British Interplanetary Society about other, passenger-carrying rockets. The paper, ‘Backyard Spaceships: Passenger-Rated Microlights for Hobby Rocketry’, argued that just as hang-gliders and microlight aircraft allowed people to enjoy the experience of flight simply for pure pleasure, so short-range passenger-carrying rockets could be developed to give people some of the experience of spaceflight. It’s quite a long and technical article, so I’ll simply quote the abstract. This runs

The FINDS and CATS prizes have introduced to contemporary astronautics the competitive spirit, which led to such spectacular advances in the fledgling aviation industry. This pioneering spirit is also shared by present day microlight aircraft enthusiasts. If the expected expansion of commercial passenger spaceflight with mass space tourism occurs, then it may create a demand for extreme short-range crewed rockets as a new form of leisure craft, Just as microlight aircraft recreate the experience of large aircraft flight on a smaller scale. If the technologies, materials and procedures used in microlight and balloon aviation are applied to those of high power solid propellant rocketry, then similar ‘microlight’ rockets able to reach altitudes of c.3,200 m, may be a possibility. Apart from the leisure and sporting opportunities offered by such craft, which would also encourage technological experimentation and progress, they would also great benefit astronautical education by adding the practical human experience of rocket flight to ground studies’ curricula. (p. 45).

The FINDS and CATS prizes were set up to encourage private organisations to develop rockets that could successfully fly into space and land again. They were deliberately established in emulation of the prizes that drove the early research into aviation and aircraft flight. These prizes were awarded in competitions for aircraft flying particular long distances, for example, and so encouraged and rewarded designers, engineers and pilots working on the designs of the planes and their engines.

A Danish organization, Copenhagen Sub-Orbitals, was also working on developing a human-carrying rocket, and have posted a few videos showing their vehicles’ test flights on YouTube. However, the last thing I read from them was that they were having difficulty making their rocket safe for humans, as the crash test dummy was always broken on landing. I don’t know whether anyone will actually go ahead and make such microlight hobby spacecraft, but the flight of the guy in his steam-powered spacecraft showed that such short-range, passenger hobby flights are possible.