Skyrora

[Ben]

Skyrora aims to build a series of suborbital rockets and a smallsat launcher, all based on hydrogen peroxide/kerosene.

Skylark Nano: 1kg to 5km
Skylark Micro: 1kg to 25km
Skyhy: 2kg to 100km
Skylark L: 50kg to 100km
Skyrora XL: 335kg to 400km polar orbit
https://www.skyrora.com - https://twitter.com/Skyrora_Ltd

So far they have shown two engine tests, one small engine in a container in the UK: https://twitter.com/Skyrora_Ltd/status/1224344215662080000

and a larger engine at a test site outside Dnipro:
https://www.aerospacetestinginternational.com/news/engine-testing/skyrora-opens-secret-rocket-engine-testing-facility.html

They say they will make their first orbital launch in 2022. https://twitter.com/Skyrora_Ltd/status/1213107911511162881

[Ben]

They have a very slick payload user's guide linked from https://www.skyrora.com/skyrora-xl

[Steven Pietrobon]

They are distilling their own HTP to 90%. All three stages use HTP/Kerosene. The Skyforce engine is using staged combustion! Payload is up to 315 kg to a 490 km sun synchronous orbit.

1st Stage: 9 Skyforce pump fed engines, 630 kN SL, 250.4 s SL Isp, 286.7 s Vac Isp
2nd Stage: 1 Skyforce pump fed engine, 85 kN, 306 s Isp
3rd Stage: 1 LEO pressure fed engine, 3.5 kN, 305 s Isp

Vehicle is 24.1 m long, 2.2 m diameter, 55.8 t lift-off mass, carbon composite monocoque structure.

[edzieba]

If nothing else, I'm exited to see HTP getting more attention.

While hard to tell from the teeeny tiny rendering of the XL third stage, the extended combustion chamber could indicate an expander-cycle engine.

[Ben]

I would wager that it's long because of the catalyst bed. A small liquid kick stage like that is likely to be pressure fed. It looks quite similar to Rocketlab Curie kick stage, image attached, or the MTV-1X; both were four spherical tank peroxide rockets.

[edzieba]

They call it out as a HTP/RP1 engine rather than HTP monoprop. Could still be a catalyst bed for a Gamma-style hypergolic ignition system though.

[lrk]

I would wager that it's long because of the catalyst bed. A small liquid kick stage like that is likely to be pressure fed. It looks quite similar to Rocketlab Curie kick stage, image attached, or the MTV-1X; both were four spherical tank peroxide rockets.

Curie runs on peroxide?  AFAIK we have never received public confirmation of the propellant used, only a "nontoxic monopropellant". 

The newest version of Curie also has been announced to have an optional biprop configuration, FWIW. 

[john smith 19]

They are distilling their own HTP to 90%. All three stages use HTP/Kerosene. The Skyforce engine is using staged combustion! Payload is up to 315 kg to a 490 km sun synchronous orbit.

1st Stage: 9 Skyforce pump fed engines, 630 kN SL, 250.4 s SL Isp, 286.7 s Vac Isp
2nd Stage: 1 Skyforce pump fed engine, 85 kN, 306 s Isp
3rd Stage: 1 LEO pressure fed engine, 3.5 kN, 305 s Isp

Vehicle is 24.1 m long, 2.2 m diameter, 55.8 t lift-off mass, carbon composite monocoque structure.

I wouldn't get too excited about this being an SC cycle. 

In British terminology the staging (wrt to HTP) can refer to partial decomposition by a catalyst pack before entry to the combustion chamber. The Gamma engines (in british terminology) were also SC engines.

It took me by surprise the first time I read about it.

A 3d printed engine is a serious achievement. If it's also an SC engine in the SSME sense of the term that's something of a breakthrough.

The obvious question is what's the T/W ratio and does it offset the lower Isp of using HTP?

[Mardlamock]

They are distilling their own HTP to 90%. All three stages use HTP/Kerosene. The Skyforce engine is using staged combustion! Payload is up to 315 kg to a 490 km sun synchronous orbit.

1st Stage: 9 Skyforce pump fed engines, 630 kN SL, 250.4 s SL Isp, 286.7 s Vac Isp
2nd Stage: 1 Skyforce pump fed engine, 85 kN, 306 s Isp
3rd Stage: 1 LEO pressure fed engine, 3.5 kN, 305 s Isp

Vehicle is 24.1 m long, 2.2 m diameter, 55.8 t lift-off mass, carbon composite monocoque structure.

I wouldn't get too excited about this being an SC cycle. 

In British terminology the staging (wrt to HTP) can refer to partial decomposition by a catalyst pack before entry to the combustion chamber. The Gamma engines (in british terminology) were also SC engines.

It took me by surprise the first time I read about it.

A 3d printed engine is a serious achievement. If it's also an SC engine in the SSME sense of the term that's something of a breakthrough.

The obvious question is what's the T/W ratio and does it offset the lower Isp of using HTP?

If they were using 98% HTP there'd be no performance loss to speak off, as for a same-volume multi-stage rocket, HTP and kerosine still generate the same total DV as a Kerolox vehicle.

[Ben]

In British terminology the staging (wrt to HTP) can refer to partial decomposition by a catalyst pack before entry to the combustion chamber. The Gamma engines (in british terminology) were also SC engines.

It took me by surprise the first time I read about it.

That is disappointing if it is the case, and inaccurate terminology. Running peroxide through a cat pack is not combustion.

A 3d printed engine is a serious achievement.

I would not go that far. Dozens of companies and student organizations have printed rocket engines. For small runs it is easier than traditional manufacturing. At this point, 3d printed engines are a sign that a company has no plan to mass produce rockets.

[john smith 19]

That is disappointing if it is the case, and inaccurate terminology. Running peroxide through a cat pack is not combustion.

Yes, it seemed a bit odd to me. It can be argued that the decomposition is the first stage toward combustion. IMHO it's a poor use of language, but that's just my opinion.

I would not go that far. Dozens of companies and student organizations have printed rocket engines. For small runs it is easier than traditional manufacturing. At this point, 3d printed engines are a sign that a company has no plan to mass produce rockets.

I'm not really sure if any rocket builder is trying to "mass produce" rockets. I'd say at present 12 launches a year from a pad is pretty regular, 15  to 24/year would be a very serious.  I'd say 3d printing can handle that.

[Steven Pietrobon]

Maybe there's some confusion. A keroxide staged combustion engine would have as part of its cycle the full decomposition of HTP which would drive the turbo pump. The decomposed HTP would then go into the combustion chamber. HTP flow is from the tank, to the turbo pump, part of which goes through the combustion chamber walls, the catalyst bed, turbo pump turbine and then the combustion chamber. Unlike a normal staged combustion engine, no fuel is required by the "pre-burner".

[daedalus1]

Maybe there's some confusion. A keroxide staged combustion engine would have as part of its cycle the full decomposition of HTP which would drive the turbo pump. The decomposed HTP would then go into the combustion chamber. HTP flow is from the tank, to the turbo pump, part of which goes through the combustion chamber walls, the catalyst bed, turbo pump turbine and then the combustion chamber. Unlike a normal staged combustion engine, no fuel is required by the "pre-burner".

Isn't decomposed HTP just water?

[randomly]

Water and Oxygen

[daedalus1]

Water and Oxygen

I mean after the oxygen is used for the turbine.
So you wouldn't want to inject water into the combustion chamber.

[john smith 19]

Water and Oxygen

I mean after the oxygen is used for the turbine.
So you wouldn't want to inject water into the combustion chamber.

It doesn't work that way.

The catalytic decomposition of HTP is water and Oxgyen at high temperature. So it's basically a steam turbine. Water injection has been used on rockets to increase thrust and cool the combustion chamber IIRC Ariane IV used this on its hypergolic engines. 

Being high temperature steam doesn't cool combustion much and its mass adds to the thrust. The high temperature steam is what makes it hypergolic with kerosene.

[Steven Pietrobon]

Being high temperature steam doesn't cool combustion much and its mass adds to the thrust. The high temperature steam is what makes it hypergolic with kerosene.

Pretty sure high temperature steam is not hypergolic with kerosene. :-) Its the high temperature oxygen that is hypergolic.

[john smith 19]

Being high temperature steam doesn't cool combustion much and its mass adds to the thrust. The high temperature steam is what makes it hypergolic with kerosene.

Pretty sure high temperature steam is not hypergolic with kerosene. :-) Its the high temperature oxygen that is hypergolic.

Well spotted. Yes.  I was  thinking if only you can get LOX hot enough ignition should not be a problem. Then I recalled that you can with resonance ignition but it seems to be quite slow to operate.

[baldusi]

In practical terms, the steam is hot. And turbines are thermal machines. So it works just as well as a staged combustion engine, only with more reliability. 98% HTP can get as hot as 1100K, which a lot more than normal (RD-180 handles about 850K). In the Russian literature, it would be a liquid-gas engine, which is a bit more accurate (but mixes expander, catalyst and combustion types).

[FutureSpaceTourist]

https://twitter.com/astro_zach/status/1263027200820944896

Here is footage of the first rocket static fire test to take place in the UK for 50 years, conducted last Friday by @Skyrora_Ltd

https://www.forbes.com/sites/jonathanocallaghan/2020/05/20/major-rocket-test-takes-place-in-the-uk-for-the-first-time-in-50-years/