Europe's Biggest Amateur Rocket Completes Test-Firing

Michael Eriksen writes "The Danish amateur rocket group Copenhagen Suborbitals has successfully test fired their rocket (article in Danish). It is a 90,000 kW monster delivering a total of 140,000 N. According to the group, this is by far the biggest amateur rocket ever fired in Europe. The final goal is a manned (!) low-orbital flight."

Comments

140000 Newton

[MichaelSmith]

..is 14000 kilograms force. So the total mass of your spacecraft at launch will be 7000kg (or less) if you want to accelerate at 1g initially. In practice you would want more that that so 3-4 tonnes is probably the limit for the whole spacecraft.

Re:140000 Newton

[freedom_india]

No.
It takes close to 456,521 kilograms force to lift a weight of 7,000 Kg (Stage 1 Rocket).

Re:140000 Newton

[MichaelSmith]

No. It takes close to 456,521 kilograms force to lift a weight of 7,000 Kg (Stage 1 Rocket).

Are you talking about mass to orbit? I mean mass just off the ground at launch.

Re:140000 Newton

[Big Smirk]

Saturn V was a 'multi-gear' rocket. To lift off the pad, all 5 main rockets fired. As altitude increased, the center rocket turned off to minimize stress on the rocket (stay subsonic???)

Space shuttle also has multiple speeds. If you remember the Challenger disaster - the last message from ground was "Go with throttle up" Apparently the shuttle was high enough to go full throttle (again) and not worry about aerodynamic stresses.

One of the issues with the shuttles solid rocket boosters - they are steerable - allowing insertion into a very precise orbit.

Compare that with the typical home built - solid rocket, that basically goes were you point it...usually...give or take a bit.

I worked at NASA 10 years ago and can tell you I have never seen or worked with such a hardworking, under paid (compared to the commercial world) bunch of engineers. Buildings built in the 60s, linoleum tile not matching (patched so many times) - to the point that my wife (a teacher) commented that she used to think schools were in bad shape. All the money goes into the projects.

Re:140000 Newton

[Big Smirk]

Sorry, I took your response to be the typical "government wasting money by buying $700 hammers" (which is a myth anyway).

In NASA, with ever tightening budgets, there is no room for a fat-cat middleman to make huge sums of money.

And yes, I think a good way to spend the stimulus is to invest in NASA. I bet 99% of the money will be spent in the USA paying middle class workers (those that will buy things like new cars). The only question I have is: "Is there something that gives us the same financial return - but gives us better social return?" Like investing in medical equipment research. You get the same middle class income distribution channel - and maybe more relevant benefits to citizens.

Well for now its military 1st, social programs 2nd, Science/NASA a distant whatever (4th? 5th?)

Re:140000 Newton

[ikeleib]

Saturn V was a 'multi-gear' rocket. To lift off the pad, all 5 main rockets fired. As altitude increased, the center rocket turned off to minimize stress on the rocket (stay subsonic???)

Space shuttle also has multiple speeds. If you remember the Challenger disaster - the last message from ground was "Go with throttle up" Apparently the shuttle was high enough to go full throttle (again) and not worry about aerodynamic stresses.

Most liquid fueled rockets are throttleable. Both the space shuttle and Saturn V's throttle down to avoid putting "too much stress" on the airframe. What this really means, is that they didn't want to put more weight into airframe structure, and instead reduce throttle to the point where the atmosphere thins enough that one can throttle up without surpassing the design strength of the airframe. By the way, this point is called Max-Q and for the space shuttle, it is at 11km in altitude. For the space shuttle main engines, this means they throttle up to 104% of specification power (due to improvements over the years, the SSME maximum safe throttle is actually 109% of specification).

One of the issues with the shuttles solid rocket boosters - they are steerable - allowing insertion into a very precise orbit.

Compare that with the typical home built - solid rocket, that basically goes were you point it...usually...give or take a bit.

The problem with solid rocket motors for space travel is two fold. The first is that they cannot be throttled or turned off. The second is that they are considerably less efficient pound-for-pound than liquid fueled rockets. The typical measure of rocket efficiency is specific impulse, which is measured in seconds. For example, the solid rocket boosters of the shuttle have a specific impulse of 242 seconds, while the space shuttle main engines produce a specific impulse of 363.

Re:Top Gear's Reliant Robin rocket?

[mattaw]

Well the word "rocket" is both an engine and a vehicle in common English usage scenarios. Hence it could be completely accurate to say that it is the largest rocket (i.e. engine, source of thrust) while it isn't the largest rocket (vehicle, reliant robin).

M

I was there

[kobotronic]

Up-close videos from the test:
http://www.vimeo.com/3531197

Pretty cool stuff, the whole team is all smiles. What was tested is a scaled-up design from a smaller hybrid rocket motor. The fact that the burn was even and stable demonstrates that the motor design is sound, and the math checks out. As such the team remains confident that an atmospheric launch of either this specific rocket or its twin can be carried out by mid-summer. Also, work continues on scaling the design further for the HEAT booster with a body diameter of 60 centimeters (3 times the diameter of the HATV rocket tested yesterday). The goal of the HEAT booster program is to develop a safe, economical and environmentally friendly man-rated sub-orbital propulsion technology. On the www.copenhagensuborbitals.com website you can read about their miniature spacecraft that would sit atop HEAT and carry a would-be astronaut on a no doubt exciting suborbital flight.

Re:I was there

[andrew.w.moore]

No detraction from their achievements but far from perfect:

Any comments on the nozzle burning through; it can be seen clearly at 1:05-6 http://www.vimeo.com/3531197 flying off "vertically"; look carefully and the nozzle is heating up then "ping" - once the nozzle cone has gone then the burn starts to go turbulent.

This is also very clear in the high-speed footage of this event from the www.copenhagensuborbitals.com site.

Also the engine shutdown seems very messy - lots of random bits'n'pieces thrown about (e.g. down through the flame) - looks like the top of the inside of the booster section sucked down through the ignition chamber.

Well this stuff will be fixed I am sure and congratulations to them.

Re:I was there

[kobotronic]

Thanks for the comments. I see now that the compressed timeline of the high speed video may be a bit confusing: I contracted for this brief summary the parts of the video that was essentially showing a stable, unchanging situation and left only the highlighted incidents. The burn becomes strongly turbulent only as the injector pressure has dropped appreciably, closer to flameout. The shutdown is rather messy, but I don't think that has significant impact on the flight trajectory.

We'll be releasing a video later this week with a synchronized time and data track.

Re:Exhaust nozzle blows off after a 2:02

[kobotronic]

Actually, no. The nozzle ring sits on for 10+ seconds.
At 00:34 in the video you can see it fly off, the distinct luminous object leaving the rocket, which ignites at 00:19. I'm no booster specialist (I work video and telemetry), but my understanding is that the booster team is satisfied that at the time of nozzle failure the expansion effect (produced or supported by the nozzle) is no longer required. In any case a thicker nozzle wall has already been drafted for the next test.

The high speed (1200fps) footage closeup (side view) is edited timewise; the whole thing takes about an hour to play back at 30fps. We'll be releasing a video with time codes and more data later this week.

Re:As I have a Danish surname and live in UK

[qmaqdk]

As a Dane I must say that the best beer comes from Belgium and Germany. Although the Irish have some good stuff as well.

Re:And so what...

[byrskov]

While it may not have been on purpose (and probably doesn't really qualify for a proper "nuking"), the United States Airforce have in fact dropped four nukes on Denmark, just 41 years ago.

http://en.wikipedia.org/wiki/1968_Thule_Air_Base_B-52_crash

To quote the article: "The conventional high explosive components of four B28FI model hydrogen bombs detonated on impact, spreading radioactive material over a large area in a similar manner to a dirty bomb, although a nuclear explosion was not triggered. The extreme heat generated as 225,000 pounds of unused aviation fuel burned for the next 5 to 6 hours melted the ice sheet, causing some wreckage and munitions to sink to the ocean floor".

And to make matters even more interesting, only wreckage from three of the four bombs were found.

700 Danish and American people worked on the cleanup project for 9 months, often without adequate protection. A lot of the locals and cleanup crew have subsequently gone to court over alleged radiation poisoning. Oh, and did I mention that the nukes stored on Greenland was a breach of Denmark's nuclear free zone policy, and were stored there without permission?

It's all fun and games when you're the big guy.

Re:Interference Patterns

[kobotronic]

http://www.allstar.fiu.edu/aero/rocket3.htm

Rocket folk call them diamond patterns. This article gives a good explanation.

Re:As I have a Danish surname and live in UK

[digitig]

Germany (and Czech Republic) for lager. Belgium for krieks and lambics. Ireland for stout. England for bitter. America for soda water with alcohol and beer flavoring [1]. Denmark for?

[1] And yes, I know America has some great microbreweries. The problem is with the prefix "micro".