Amateur rocket to orbit

[sevenperforce]

30 minutes ago, Steel said:

No, but I think a hybrid is a much easier motor to work with. Gives you the benefits of throttling without the inherent difficulties of a liquid bi-prop engine (fuel mixing, two sets of plumbing e.t.c)

Something like the GIRD rocket first built by the Soviets is a mixture of liquid and hybrid tech and is VERY easy to build and test:

http://www.russianspaceweb.com/gird09.html

[sevenperforce]

Some preliminary calculations...

We can put a 4-10 kg payload into LEO (120x120 km, 0 degrees from sea launch at the equator) with a 12-tonne 2.5-stage launch vehicle if we can manage the following:

• HTP+jellied petrol first stage and boosters
  • Propellant mass fraction of 85%
  • Vacuum Isp of 240s
  • Dry TWR of 15:1
• Solid-fueled second stage
  • Propellant mass fraction of 80%
  • Vacuum Isp of 200s
  • Dry TWR of 20:1

Propellant mass fraction on the hybrid is going to be the biggest challenge. For reference, the extremely well-designed Stratos II+ hybrid rocket built by DARE students in the Netherlands has a propellant mass fraction of roughly 50%. HTP has a much better density than nitrous, of course, but it's still a big challenge.

[BillKerman1234]

I think with a takeoff mass off 51 tons, that will work.

[sevenperforce]

16 minutes ago, BillKerman1234 said:

I think with a takeoff mass off 51 tons, that will work.

51 tonnes is way too big. Falcon 1 was 85 tonnes. 

Smallest orbital rocket ever launched was the SS-520 at just under 3 tonnes.

Individual rocket components need to be transportable by road w/o difficulty, so any unfueled component over half a tonne is right out.

The specification above uses 5 cores that are each 300 kg empty and 2.3 tonnes fully-fueled, with a 60-kg upper stage, and a liftoff TWR of 1.8:1 on a GLOW of under 12 tonnes.

Total combined takeoff thrust of 210 kN is about three times that of a SuperDraco and only 17% higher than the Stratos II+, but with a lower TWR than the Stratos II+ you might need a flame trench.

[sevenperforce]

Wall thickness and fineness ratio are becoming major questions in estimating mass ratios.

I wonder if a small electric pump for the HTP would be helpful.

If we run into propellant mass fraction issues, it might be useful to consider a kerosene+HTP electric-impeller-fed liquid engine with concentric tanks for strength. 

[wumpus]

4 hours ago, sevenperforce said:

Some preliminary calculations...

We can put a 4-10 kg payload into LEO (120x120 km, 0 degrees from sea launch at the equator) with a 12-tonne 2.5-stage launch vehicle if we can manage the following:

A better question would be "how much mass does it take to send a Sputnik style 'beep' to Earth?".  4-10 *grams* might be better.

3 hours ago, sevenperforce said:

51 tonnes is way too big. Falcon 1 was 85 tonnes.

Falcon 1 had a $90,000,000.00 budget (or spent that much, Musk was in trouble even with success).  The most obvious way to reduce that cost by orders of magnitude is to reduce the mass to orbit by orders of magnitude.

47 minutes ago, sevenperforce said:

I wonder if a small electric pump for the HTP would be helpful.

What is so important about HTP?  Some quotes from Ignition!:

Spoiler

Quote

Name a substance at random, and there's a 50-50 chance (or better) that it will catalyze peroxide decomposition

There were certain substances, stannates and phosphates, for instance, that could be added to peroxide in trace quantities and would stabilize it a bit by taking certain transition metal ions out of circulation, but their usefulness and potency was strictly limited; and they made trouble when you wanted to decompose the stuff catalytically. The only thing to do was to keep the peroxide in a tank made of something that didn't catalyze its decomposition (very pure aluminum was best) and to keep it clean. The cleanliness required was not merely surgical —it was levitical. Merely preparing an aluminum tank to hold peroxide was a project, a diverting ceremonial that could take days. Scrubbing, alkaline washes, acid washes, flushing, passivation with dilute peroxide —it went on and on. And even when it was successfully completed, the peroxide would still decompose slowly; not enough to start a runaway chain reaction, but enough to build up an oxygen pressure in a sealed tank, and make packaging impossible. And it is a nerve-wracking experience to put your ear against a propellant tank and hear it go "glub" —long pause — "glub" and so on.  After such an experience many people, myself (particularly) included, tended to look dubiously at peroxide and to pass it by on the other side.
...
Ignition of a hydrogen peroxide system, particularly one burning gasoline or jet fuel, was always a problem. In some cases, a solution of calcium permanganate was injected along with the propellants atthe start of the run, but this was an awkward complication. In som tests (at MIT) a small amount of catalyst (cobaltons nitrate) was dis-solved in the peroxide, but this reduced its stability. The fuel was kerosene with a few percent of o-toluidine. A hypergolic or easily ignited starting slug (generally hydrazine, sometimes containing a catalyst) could lead the fuel. An energetic solid-propellant pyrotechnic igniter was used in some cases. Probably the most reliable, and hence the safest, technique was to decompose part or all of the per-oxide in a separate catalyst chamber, lead the hot products into the main chamber, and inject the fuel (and the rest of the oxidizer, if any) there. (A stack of screens made of silver wire was an efficient catalyst array.) NARTS designed and fired a motor which incorporated the catalyst chamber in the main chamber.
...
For when we —and other people —tried it again (fortunately on a smaller scale) the results were different. The jet fuel burns quietly at first, then the flare burning starts coming, and its frequency in-creases. (That's the time to start running.) Then, as the layer of JPgets thinner, the peroxide underneath gets warmer, and starts to boil and decompose, and the overlying fuel is permeated with oxygen and peroxide vapor. And then the whole shebang detonates, with absolutely shattering violence.

When the big brass saw a demonstration or two, the reaction was "Not on my carrier!" and that was that.
...
Higher concentrations (you can buy 98 percent stuff now) have appeared in the last few years, and they appear to be rather more stable than the 90 percent material, but all the drum beating indulged inby the manufacturers hasn't got the bridesmaid into a bridal bed. Peroxide just didn't make it.

 

7 hours ago, sevenperforce said:

A few major points:

• Veto on recovery of the upper stage or payload. Minimum possible payload.
• Veto on expendable side boosters. The point is to be able to do this on the cheap and so we need to do non-destructive testing. We can test-fire the boosters as sounding rockets and recover as chutes. Maybe do test suborbital spaceflights using a single solid motor on top of a recovered booster.
• Veto on any air-started liquid rocket. Ignition is a tough enough problem on the ground, and true hypergolics are far beyond what we could pull off. The only way we could conceivably manage an air-started hybrid motor is that decomposed HTP is hypergolic with hydrocarbons.

Along with many other advantages, parallel staging allows us to use differential throttling in place of gimbal for in-atmosphere and exoatmospheric attitude control. It is the only way to do attitude control without drag or cosine losses, and it is essentially "free" because we need fine throttleability of our boosters already. Boosters can either have fixed fins (to help hold prograde) or controllable fins for roll control.

Additional hybrid advantage is venting steam from the pressure chamber as automatic RCS for attitude control of the core.

If we can get away with fixed fins, then ideally the only moving parts on the rocket are little valves actuated by a small controller. It will save money if every single valve is identical.

It may be cheaper to synthesize HTP than it would be to try and source it.

Recovery is obviously not in the budget.  I still like the idea of parachutes replacing upper stages during testing.

Are you for or against side boosters?  First you "veto" it, then you use them for guidance.  I'd strongly recommend them to avoid ignition of liquids in flight while still getting a "stage and a half" out of ground ignited stages.

- don't forget nitrous - propane for an intermediate stage.  Although it would likely be canceled thanks to slow self ignition.  While this wouldn't be a problem in flight, building the appropriate test stand to develop slowly igniting hypergolics (without pooling below the engine) is probably enough to can the idea.

Synthesizing fuels are never a good idea, and storing HTP is a huge problem.  I don't recall John Clark *ever* being interested in synthesizing his own fuels in Ignition!  On the whole it sounds more likely to get a rocket scientist blown up.

[BillKerman1234]

i would agree with you. Also, you should join our slack account, that’s were me and sevenperforce are discussing the launch vehicle in more depth. Click here: https://join.slack.com/t/amaturerockettoorbit/shared_invite/enQtNDM2NzEzMjA1Mjg2LTdkZDY2YTI1ZTNjYmNlNzJiMmQ2MTBmYjUzY2JhNWMxMmNkMGE2NzYwOGRmMzQzYWM4MGM2ZTZkYWMzOWI2ZDc

[ChrisSpace]

10 hours ago, BillKerman1234 said:

Okay, I’ve just created a slack account, you can join here: 

https://join.slack.com/t/amaturerockettoorbit/shared_invite/enQtNDM0NjgxMTcxMjM2LWY5NmM5YWEwYTY2ZDU1M2ZhYWJiYzA5MmNhNDBiNTJmNTA4NDMwZjE4MWMzYzA3ZWFkY2JiNzNmNWQ1OGE2NjU

 

I'll join once I get my main laptop back (the one that I can actually access my email with and that I have my extra info on)

8 hours ago, sevenperforce said:

A few major points:

• Veto on recovery of the upper stage or payload. Minimum possible payload.
• Veto on expendable side boosters. The point is to be able to do this on the cheap and so we need to do non-destructive testing. We can test-fire the boosters as sounding rockets and recover as chutes. Maybe do test suborbital spaceflights using a single solid motor on top of a recovered booster.
• Veto on any air-started liquid rocket. Ignition is a tough enough problem on the ground, and true hypergolics are far beyond what we could pull off. The only way we could conceivably manage an air-started hybrid motor is that decomposed HTP is hypergolic with hydrocarbons.

Agreed on all points, especially the first two and ESPECIALLY the second one. To make this at all practical we need the cost per kilogram to be $10,000 or less, preferably much less.

[wumpus]

1 hour ago, sevenperforce said:

I wonder if a small electric pump for the HTP would be helpful.

Crazy tin can idea:

according to the "infallible wiki" (some criticism of my use of that phrase) https://forum.kerbalspaceprogram.com/index.php?/topic/91282-for-questions-that-dont-merit-their-own-thread/&page=85

Diesel direct injection can be used with pressure of an order of magnitude greater than needed by a turbopump (or at least in the combustion chamber).  Unfortunately, no such numbers are so readily available for GDI (gas direct injection: we could presumably use diesel fuel as our rocket fuel, but diesel injectors require diesel fuel for lubrication.  I strongly suspect the oxidizer may have to go through GDI injectors, which are less mature.  Or we could use kerosene or ethanol and two sets of GDI injectors (I'd assume we would use *lots* of injectors, at least the whole "rails" worth, and probably multiple "rails").

I don't pretend that I'd expect such a rocket would have a TWR >1, but it might be a highly efficient rocket and quite useful for a second stage (assuming you are willing to ignite it).  My understanding is that 20-40 minute burns to orbit are pretty standard, and this type of thing might be an option.  The whole point is that the last think I want to build for a rocket is a turbopump: and if I can find such a thing on the shelf (or better yet, a junkyard) I will grab it while I can.

- just stand as far away as possible when trying to put LOX through a fuel injector, especially the first time (perhaps we route LOX around the nozzles to cool them and fuel around the injectors to keep them from freezing).

 

[ChrisSpace]

6 hours ago, sevenperforce said:

Something like the GIRD rocket first built by the Soviets is a mixture of liquid and hybrid tech and is VERY easy to build and test:

Some numbers on the cost/mass/thrust/Isp of such an engine would be useful.

5 hours ago, sevenperforce said:

We can put a 4-10 kg payload into LEO (120x120 km, 0 degrees from sea launch at the equator) with a 12-tonne 2.5-stage launch vehicle if we can manage the following:

• HTP+jellied petrol first stage and boosters
  • Propellant mass fraction of 85%
  • Vacuum Isp of 240s
  • Dry TWR of 15:1
• Solid-fueled second stage
  • Propellant mass fraction of 80%
  • Vacuum Isp of 200s
  • Dry TWR of 20:1

 Propellant mass fraction on the hybrid is going to be the biggest challenge. For reference, the extremely well-designed Stratos II+ hybrid rocket built by DARE students in the Netherlands has a propellant mass fraction of roughly 50%. HTP has a much better density than nitrous, of course, but it's still a big challenge.

How does this compare with the earlier design?

[BillKerman1234]

5 minutes ago, wumpus said:

Crazy tin can idea:

according to the "infallible wiki" (some criticism of my use of that phrase) https://forum.kerbalspaceprogram.com/index.php?/topic/91282-for-questions-that-dont-merit-their-own-thread/&page=85

Diesel direct injection can be used with pressure of an order of magnitude greater than needed by a turbopump (or at least in the combustion chamber).  Unfortunately, no such numbers are so readily available for GDI (gas direct injection: we could presumably use diesel fuel as our rocket fuel, but diesel injectors require diesel fuel for lubrication.  I strongly suspect the oxidizer may have to go through GDI injectors, which are less mature.  Or we could use kerosene or ethanol and two sets of GDI injectors (I'd assume we would use *lots* of injectors, at least the whole "rails" worth, and probably multiple "rails").

I don't pretend that I'd expect such a rocket would have a TWR >1, but it might be a highly efficient rocket and quite useful for a second stage (assuming you are willing to ignite it).  My understanding is that 20-40 minute burns to orbit are pretty standard, and this type of thing might be an option.  The whole point is that the last think I want to build for a rocket is a turbopump: and if I can find such a thing on the shelf (or better yet, a junkyard) I will grab it while I can.

- just stand as far away as possible when trying to put LOX through a fuel injector, especially the first time (perhaps we route LOX around the nozzles to cool them and fuel around the injectors to keep them from freezing).

 

Ok, we already came to the conclusion (on slack) that a ten ton hybrid with 3 boosters and 2 small solid upper stages would work with 4 kg payload, maybe a diesel lox upper stage would work? I’ll think about it tomorrow, it’s 21 past 12pm in London, so I have to go to bed. Goodnight.

[ChrisSpace]

Minor update: I have some ideas for the payload. First, instead of using a normal camera, to save weight we could try one of the ultra-tiny ones:

https://www.amazon.com/dp/B076HMSQ2L/?tag=097-20&ascsubtag=v7_4_3_1ier_49nu_0_x01_-srt-

https://www.amazon.com/dp/B074SMM191/?tag=097-20&ascsubtag=v7_4_3_146f_3tsn_0_x01_-srt-

Second, what about 3D printing some of the components for the payload (or rocket)? Things like the structure, tanks and so on.

Third, how about this for a scientific payload: A few different biological specimens, which would be observed to further analyse the long-term impacts of microgravity and/or cosmic radiation on living systems for extended periods of time? Specifically I'm thinking we use one of these:

https://www.amazon.com/dp/B005IZOB5M/?tag=097-20&ascsubtag=v7_4_3_133_hc_0_x01_-srt-

If we use a self-sustaining ecosystem like that as a payload, all it'll need to be supplied with is light and thermal insulation. I think it's a good idea, of course the payload could instead be an Earth-observation satellite.

[BillKerman1234]

5 hours ago, ChrisSpace said:

Minor update: I have some ideas for the payload. First, instead of using a normal camera, to save weight we could try one of the ultra-tiny ones:

https://www.amazon.com/dp/B076HMSQ2L/?tag=097-20&ascsubtag=v7_4_3_1ier_49nu_0_x01_-srt-

https://www.amazon.com/dp/B074SMM191/?tag=097-20&ascsubtag=v7_4_3_146f_3tsn_0_x01_-srt-

Second, what about 3D printing some of the components for the payload (or rocket)? Things like the structure, tanks and so on.

Third, how about this for a scientific payload: A few different biological specimens, which would be observed to further analyse the long-term impacts of microgravity and/or cosmic radiation on living systems for extended periods of time? Specifically I'm thinking we use one of these:

https://www.amazon.com/dp/B005IZOB5M/?tag=097-20&ascsubtag=v7_4_3_133_hc_0_x01_-srt-

If we use a self-sustaining ecosystem like that as a payload, all it'll need to be supplied with is light and thermal insulation. I think it's a good idea, of course the payload could instead be an Earth-observation satellite.

No point, the payload will be good enough to get multiple kg in to orbit, any less and the 95-100 success rate goes from 0 to 5kg, that’s too risky, so we will have the mass for a proper GoPro, and remember how heavy a kg is, we have a lot of mass to work with. As for the aquarium, not an option. I’m no expert, but the water has to be oxygenated somehow. In micro gravity and air on top to form a ‘surface’ would float as bubbles through the water.

Edited September 14, 2018 by BillKerman1234

[wumpus]

4 hours ago, BillKerman1234 said:

No point, the payload will be good enough to get multiple kg in to orbit, any less and the 95-100 success rate goes from 0 to 5kg, that’s too risky, so we will have the mass for a proper GoPro, and remember how heavy a kg is, we have a lot of mass to work with. As for the aquarium, not an option. I’m no expert, but the water has to be oxygenated somehow. In micro gravity and air on top to form a ‘surface’ would float as bubbles through the water.

95-100 success rate?  Real life isn't KSP and nearly everyone's first rocket explodes or otherwise doesn't make it to orbit.  The Russians didn't mention any flight that hadn't already succeeded and do you know *any* rocket program whose first attempt to orbit succeeded?  0-5 is more likely, although I'd still advocate the "just a few grams" satellite if you want a chance.  There are a few threads about "attempts to make a rocket engine" and see how many of them were successful in producing *any* thrust on the first go, let alone the thrust calculated as needed.  SpaceX had a $90M dollar budget and still took 4 tries to get to orbit (don't ask about NASA.  And for all the noise Blue Origin makes, they haven't launched an orbital craft yet).

[sevenperforce]

15 hours ago, wumpus said:

A better question would be "how much mass does it take to send a Sputnik style 'beep' to Earth?".  4-10 *grams* might be better.

I'd be happy with 4-10 grams, too -- anything big enough to transmit. The issue is that when we start to do extreme miniaturization, the benefits start to drop off considerably.

Once the payload is less than half the dry mass of your terminal stage, decreasing the mass of the payload is really no longer necessary because it only adds a tiny amount of extra dV, since the dry mass of the terminal stage dominates the rocket equation.

The other solution is to add yet another stage...but below a certain size, mass-efficient solid-fueled stages are simply not a thing, due to square-cube losses.

15 hours ago, wumpus said:

What is so important about HTP?  Some quotes from Ignition!:

<snip>

So, Ignition! is a fantastic book, but I do think some of the danger is exaggerated for comedic and dramatic effect. HTP isn't very nice, to be sure, but it's doable. This guy synthesizes his own HTP to build monoprop jetpacks and he hasn't exploded yet.

More to the point, HTP is the only dense, non-toxic, non-cryogenic liquid oxidizer available, period.

15 hours ago, wumpus said:

Recovery is obviously not in the budget.  I still like the idea of parachutes replacing upper stages during testing.

Would have to build at least 4x as many cores if we don't do recoverable test.

Recovery of side boosters is still on the table for the orbital flight if our margins are good enough.

15 hours ago, wumpus said:

Are you for or against side boosters?  First you "veto" it, then you use them for guidance.  I'd strongly recommend them to avoid ignition of liquids in flight while still getting a "stage and a half" out of ground ignited stages.

Sorry, I mean vetoing the expendability of the side boosters. See above.

[ChrisSpace]

5 hours ago, BillKerman1234 said:

No point, the payload will be good enough to get multiple kg in to orbit, any less and the 95-100 success rate goes from 0 to 5kg, that’s too risky, so we will have the mass for a proper GoPro, and remember how heavy a kg is, we have a lot of mass to work with.

In that case it would be better to use a camera designed for use in space, like the cubesat one.

5 hours ago, BillKerman1234 said:

As for the aquarium, not an option. I’m no expert, but the water has to be oxygenated somehow.

It says it's a completely closed ecosystem so I assumed that includes oxygen.

5 hours ago, BillKerman1234 said:

In micro gravity and air on top to form a ‘surface’ would float as bubbles through the water.

Would this necessarily be a bad thing? What if the payload is given a small spin to keep the air near the centre?

[James Kerman]

Not that I don't think a scientific payload is a worthy ideal, it's just that this has never been done by a amateur group before so I believe any attempt should use as little mass as possible.

[sevenperforce]

10 minutes ago, James Kerman said:

Not that I don't think a scientific payload is a worthy ideal, it's just that this has never been done by a amateur group before so I believe any attempt should use as little mass as possible.

Agreed. Getting even an empty rocket stage to orbit one time (and being able to confirm it) is enough.

[ChrisSpace]

Any progress updates?

[Ultimate Steve]

On 9/28/2018 at 10:10 PM, ChrisSpace said:

Any progress updates?

The group settled on a three stage design, two solid stages and a HTP/Kerosene lower stage. Thanks to rapid development made possible by the investment of a billionaire, they had test firings by the end of the week, and made an orbital launch attempt two days ago at a base in Eastern Nebraska. The payload was a tiny transmitter with enough battery to transmit "Never Gonna Give You Up" from orbit for a few hours. The launch was a complete success, the transmitter entered orbit a bit higher than planned, actually. But then the FBI showed up and arrested them both for rocketry experiments and copyright violations. The evidence of the launch has been wiped, and the engineers are undergoing interrogations. Their forum accounts are maintained by professional imitators. A second launch was scheduled to take place in a few hours but I doubt it will happen.