Orbex

[ringsider]

Interesting comment in the Financial Times today:

https://www.ft.com/content/e0969502-c246-4b3c-9193-5b4196c1dbd5

Extract:

However, Orbex is already discussing the possibility of developing a larger rocket to meet demand, even before it makes its first flight with Prime, according to both Chambers and Coates. This would require substantial extra funding, according to analysts. “For sure those thoughts are happening,” Coates said. “Prime is the start. It is the beginning of the journey for this organisation.”

“Logically it makes sense if you want to drive prices down, all this can only really happen with a larger rocket,” Chambers told the FT. “The question is how will it be supported financially.”

[deathofapenguin]

Artile shared today about Orbex's new patent on co-axial tanks, includes a picture of a loaded propellant tank, this appears to be one of the first images of any hardware testing we have from them.

https://orbex.space/news/orbex-secures-international-patent-for-coaxial-rocket-fuel-tanks

[WmThomas]

How does the coaxial tank (fuel tank within the oxidizer tank) save on tank mass? I'm confused.

[trimeta]

How does the coaxial tank (fuel tank within the oxidizer tank) save on tank mass? I'm confused.

I guess in theory, if you would want to sub-chill the fuel, this approach means the oxidizer is acting like an insulator keeping the fuel cold? Orbex uses propane/LOX.

[Rik ISS-fan]

I think the technology allows for a propallent tank with higher diameter over length ratio.
The most optimal pressure vessel form factor is a sphere, afterwards come cilinders.
But you require tanks for both fuel and oxidizer, so you require two spheres or cilinders.
With the Orbex patented technology a cylindrical fuel tank can be enclosed inside a spherical oxidizer tank.
This allows a very stubby propellent tank structure 

[trimeta]

I think the technology allows for a propallent tank with higher diameter over length ratio.
The most optimal pressure vessel form factor is a sphere, afterwards come cilinders.
But you require tanks for both fuel and oxidizer, so you require two spheres or cilinders.
With the Orbex patented technology a cylindrical fuel tank can be enclosed inside a spherical oxidizer tank.
This allows a very stubby propellent tank structure

You've got a good point about fineness ratio, that may make concentric-tank rockets more capable of handling aerodynamic loads and thus launching in a wider range of weather.

[deathofapenguin]

I think there are two other benefits that haven't been mentioned. One is that since both tanks can be accessed from the bottom, the required plumbing is reduced, as there is no need for a large downcomer. That and pressurisation systems might be able to be made smaller. The mass reduction woulnd't be huge, but on a small vehicle like this it probably has a noticable effect. Scaling up to larger vehicles I doubt would be that effective though.
The other benefit is that the inner tank doesn't need to be structural, it is simply acting more as a barrier between fuel and oxidiser which would be held at roughly similar pressures. This means it wouldn't undergo much loading, so it can be made to have much thinner walls and reduce the overall weight.

[ringsider]

From the patent:

--

The present invention is in the field of rockets for launching objects, such assatellites, into space. In particular, the present invention is in the field of fuel tanks for such rockets. Various types of rockets are employed for launching objects into space.

For example, various approaches are undertaken to make the launching of satellites into space more readily accessible. Irrespective of the kinds of objects to be launched, rockets have to deal with the issue that the structure and the fuel required for launching the rocket are very heavy compared to the object to belaunched into space, commonly referred to as payload terms of the rocket dynamics.

Despite extensive efforts of increasing the efficiency of rockets in terms of minimizing the amount of fuel needed for a particular payload, the energy efficiency of state of the art rockets is still not satisfactory.

Accordingly, it would be beneficial to modify existing rocket designs for an increase in energy efficiency.

Exemplary embodiments of the invention include a rocket propellant tank arrangement for storing fuel and oxidizer for launching a rocket, the rocket propellant tank comprising an the oxygen fuel tank tank for storing liquid oxygen and a fuel tank for storing liquid fuel, wherein the fuel tank is at least partially stored within the oxygen tank.

Exemplary embodiments of the invention allow for a rocket propellant tank arrangement that is able to store highly energetic propellants, while having a lowstructural mass and thus contributing to a high energy efficiency of the overall rocket.

The arrangement of the fuel tank at least partially within the oxygen tank allows for a particularly lightweight construction of the rocket propellant tank arrangement, thus greatly contributing to the overall energy efficiency of a rocket equipped with this rocket propellant tank arrangement. It is possible to select the fuel for a particular rocket and the temperatures / pressures for the liquid fuel and the liquid oxygen in a way that the structural burden on the separation between the fuel tank and the oxygen tank is low. Also, the requirements in terms of insulation may be low.

The separation between the fuel tank and the oxygen tank may thus add much less weight to the overall structural mass of the rocket than the components required for supporting separate tanks that are surrounded by the outside environment.

Accordingly, as compared to prior approaches, where a fuel tank and an oxidizer tank were stacked in a one above the other relationship, an equivalent amount of propellants can be stored with a considerably lower structural mass.

According to a further embodiment, the fuel tank is one of a propane tank for storing liquid propane, a propene tank for storing liquid propene, and a propylene tank for storing liquid propylene. In particular, the combination of liquid oxygen and liquid propane allows for an energetically beneficial propulsion of a rocket. At the same time, the arrangement of a propane tank at least partially within the oxygen tank allows for a particularly lightweight construction of the rocket propellant tank arrangement. The separation between the oxygen tank and the propane tank does not require excessive mechanical strength and does not require excessive thermal insulation, because liquid oxygen and liquid propane can be stored at similar temperatures and similar pressures. Without burdensome requirements in terms of mechanical strength and insulation, the separation between the oxygen tank and the propane tank can be implemented in a fairly basic manner and does not add much weight to the overall weight of the rocket.

In addition, the arrangement of the propane tank at least partially within the oxygen tank allows for a mutual cooling of the liquid oxygen and the liquid propane. Also, the similar pressures within the propane tank and the oxygen tank allow for the separation between the two tanks to be a mere mechanical barrier that prevents diffusion therethrough from any of the two components, without requiring large mechanical strength in terms of pressure gradients. The propane tank does not have to be designed for being surrounded by the outside environment.

Analogous considerations apply to the combination of liquid propene and liquid oxygen as well as to the combination of liquid propylene and liquid oxygen.

According to a further embodiment, the rocket propellant tank arrangement comprises a fuel tank wall, which forms the fuel tank for storing liquid fuel. With the fuel tank being at least partially arranged within the oxygen tank, the fuel tank wall can form an effective border towards the oxygen tank at low structural massfor the reasons laid out above. The expression forming the fuel tank does not require the fuel tank wall to form an entirely enclosed space. For example, the fuel tank wall may be a cylindrical wall, with the fuel tank being closed by fuel tank caps.

According to a further embodiment, the rocket propellant tank arrangement comprises an oxygen tank wall, arranged at least partially around the fuel tank wall, with the fuel tank wall and the oxygen tank wall forming the oxygen tank for storing liquid oxygen between the fuel tank wall and the oxygen tank wall. In this way, the fuel tank wall forms both the surrounding wall around the fuel tank as well as an inner wall of the oxygen tank. In this way, liquid fuel and liquid oxygen are stored adjacent to each other, with only the fuel tank wall separating the two volumes for storing fuel and oxidizer. Again, the oxygen tank may be closed by oxygen tank caps, provided in addition to the oxygen tank wall.

According to a further embodiment, a plurality of fuel tank fixation elements are arranged between the fuel tank wall and the oxygen tank wall. In this way, a positional fixation of the fuel tank within the oxygen tank can be achieved with low complexity. As the temperature and pressure gradients between the oxygen tank and the fuel tank are small, the fuel tank fixation elements can have a low structural mass and do not have to be load bearing. In a particular embodiment, the plurality of fuel tank fixation elements may be aplurality of fixation fins. The fixation fins may be sheet-like elements extending between the fuel tank wall and the oxygen tank wall.

In a further particular embodiment, the plurality of fuel tank fixation elements maybe a plurality of slosh baffles. In this way, the fuel tank fixation elements may on the one hand provide a positional fixation of the fuel tank within the oxygen tank while at the same time reducing or eliminating undesired dynamic effects from the liquid oxygen moving within the oxygen tank. The slosh baffles may also have the form of fixation fins.

According to a further embodiment, the fuel tank wall is made of aluminium, steel, in particular austenitic stainless steel, carbon fiber based composites or composite overwrap aluminium. The latter material is aluminium, wrapped or coated with composite material, such as carbon fiber based composites. Aluminium, composite materials and composite overwrap aluminium are particularly light materials.The fuel tank wall may also be a mixture of two or more of the above materials.

According to a further embodiment, the fuel tank wall is free of insulating material. In this way, the structural mass, spent on insulating the fuel tank in prior art approaches, can be eliminated, thus increasing the overall energy efficiency of therocket. Further, with the fuel tank being at least partially arranged within the oxygen tank, the lack of insulating material in fact allows for a beneficial mutual cool-ing of the liquid oxygen and the liquid fuel.

According to a further embodiment, the fuel tank wall has a thickness of between 0.1 mm and 15 mm, in particular of between 0.5 mm and 10 mm, further in partic-ular of between mm and 5 mm. With this thickness, the fuel tank wall mayprovide an effective barrier between the liquid oxygen and the liquid fuel, while only contributing little mass to the overall weight of the rocket. The fuel tank wall may also comprise enforcing elements, such as stiffeners, stringers, isogrid fea-tures, etc. These enforcing elements may be included in above thickness values or may locally add thickness. The enforcing elements may be arranged on the in-side of the fuel tank.

According to a further embodiment, the pressure within the fuel tank and within the oxygen tank may be between 1 bar and 30 bar in operation.

According to a further embodiment, the fuel tank has a generally cylindrical shape. In this way, the fuel tank has a shape that can be surrounded by the liquid oxygen tank in a regular manner. Also a generally cylindrical fuel tank can be conveniently slid into the inner space, provided by the oxygen tank wall, during manu-facture.

According to a further embodiment, the oxygen tank has a generally hollow cylindrical shape. In other words, the space between a generally cylindrical fuel tank wall and a generally cylindrical oxygen tank wall may form a generally hollow cylinder, with this generally hollow cylinder forming the oxygen tank of the rocket propellant tank arrangement.

--

And so on, read it here:

https://worldwide.espacenet.com/patent/search/family/057796256/publication/CA3050033A1?q=Orbital%20express%20launch

Interestingly they covered propane, propene and propylene fuels, but not the fuel system used by a competing firm that appears to have discovered this concept around about the time the patent was published.

[HMXHMX]

No one does prior art searches anymore: http://www.astronautix.com/p/phoenixc.html

Phoenix C/E design used LOX, Propane (sub cooled) and LH2 in concentric low pressure tanks.

[Gliderflyer]

Seriously. A lot of hobby liquids use coax tanks, and Bagaveev Corp (jank as they were) flew a LOX/propane coax tank rocket back in 2015.

[HMXHMX]

No one does prior art searches anymore: http://www.astronautix.com/p/phoenixc.html

Phoenix C/E design used LOX, Propane (sub cooled) and LH2 in concentric low pressure tanks.

Oh, and...Chrysler SERV: http://www.astronautix.com/s/serv.html

[trimeta]

Orbex raised £16.7m ($20.8m) in an update to its Series C funding round.

https://orbex.space/news/orbex-secures-16-7m-investment-for-rocket-ramp-up-period

[catdlr]

https://twitter.com/NASASpaceflight/status/1780913144983875921

Chris Bergin - NSF
@NASASpaceflight
“Orbex is one of only two space rocket manufacturers in the UK, and the only one to also operate its own spaceport" - Phillip Chambers, CEO of Orbex.

Prime is set to launch from the Sutherland Spaceport, mainland Scotland.

[TrevorMonty]

Orbex raised £16.7m ($20.8m) in an update to its Series C funding round.

https://orbex.space/news/orbex-secures-16-7m-investment-for-rocket-ramp-up-period

Money being used to build high volume production facilities.

I think they are getting ahead of themselves and not taken on any lessons from other new small LV companies.
Both VO and Astra over captialized and poured far to much money into production facilities years before it was needed.
RL did same with Electron but was saved by SS carrying launch it until now.

There is no going from first successful launch to flying 10 missions a year within a year or two. Typically takes about three or more years. A successful launch will most likely be preceeded by 1-3 failures with months in between launches to figure out what went wrong and fix fault.

[john57sharp]

Orbex expecting to announce 2025 launch date soon.

Plans for Sutherland being scaled down.

https://twitter.com/rocketeer_uk/status/1789676969346420743?s=61&t=_FaKqlNjg5d48D95XRUojw