Author Topic: Radian Crewed SSO Spaceplane  (Read 32041 times)

Offline HMXHMX

  • Full Member
  • ****
  • Posts: 1686
  • Liked: 2088
  • Likes Given: 631
Re: Radian Crewed SSO Spaceplane
« Reply #120 on: 01/22/2022 03:44 am »
Looks interesting, wish Gary and all the other team members good luck!

Thanks, but I'm not currently involved Ė working other projects.  I and my colleague Bevin McKinney did some concept trade studies and built some engine hardware for Radian over the years but aren't currently part of the effort.  But best of luck to them.

Offline Rocket Science

  • Senior Member
  • *****
  • Posts: 10583
  • NASA Educator Astronaut Candidate Applicant 2002
  • Liked: 4532
  • Likes Given: 13520
Re: Radian Crewed SSO Spaceplane
« Reply #121 on: 01/25/2022 01:19 am »
What I don't understand is what does SSTO buy you over a streamlined TSTO system that's compromised of two independent rapidly reusable vehicles.

I mean by definition you'll be lugging your first stage to orbit and then re-entering it.

Not only will it be more complex and expensive, but you also won't have it back in 20 minutes to launch again..

I see the allure when compared with a traditional "pieces fall off" type rocket, but I just don't see the motivation at the present time.

1. The ability to operate from a runway, even if you have to drag a launch sled along with you to do it, dramatically simplifies your ground handling and infrastructure. It also gives you more flexibility when deciding where to launch from.

2. Being an SSTO, no time or money (money is the far more important part) has to be spent between flights on vehicle integration, only payload integration. Yes, stage integration has historically been far less efficient than it could be. That doesn't change the fact that no integration is still faster and cheaper, particularly since that means you don't need to build and/or maintain and/or travel-to the facilities needed for stage integration. (Unless you decided to use a launch sled, in which case I guess reintegration with the sled is basically stage integration. I really don't like the sled.)

3. Even SpaceX isn't seriously consider launching the same vehicle more than once a day, so having to wait at least 90 minutes to get the vehicle back is hardly an issue.

4. This is in some ways more of an idle thought than a point. I would also think that a reusable TSTO should be inherently simpler than an SSTO. That said, the main example we have of a RTSTO design is Starship, which is using the most complicated rocket engine ever developed. Only time will tell, but it may be the most teams designing RTSTOs willingly give up their simplicity advantage in favor of further boosting their performance advantage.
TAV concept had a jet sled launch...
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator

Offline libra

  • Full Member
  • ****
  • Posts: 1820
  • Liked: 1201
  • Likes Given: 2359
Re: Radian Crewed SSO Spaceplane
« Reply #122 on: 01/25/2022 11:03 am »
And nowadays with drones it would be a bit easier to built. Incidentally, Aevum is trying just that except the other way around: supersonic drone air launching small rockets.

Offline Asteroza

  • Senior Member
  • *****
  • Posts: 2234
  • Liked: 792
  • Likes Given: 29
Re: Radian Crewed SSO Spaceplane
« Reply #123 on: 01/26/2022 02:13 am »
(Although we donít know what theyíre usingÖ if itís hydrolox like X-33, then they will struggle. Itís one of the worst SSTO propellants to use because of its low density.)

I'd caveat that statement re: low density of hydrolox with "when used at normal mixture ratios in normal rocket engines". With LOX-rich TAN, you could theoretically make a stage O/F ratio of 12-18:1 work (instead of the traditional 4-6:1), which would help bulk density a ton, at the cost of lower Isp during the boost phase (which does help lower gravity losses though).

I do agree though that pure LOX/LH2 at traditional mixture ratios has crappier bulk density than you'd want for an SSTO.

When Aerojet did their TAN papers, they also looked at tri-propellant TAN -- where the main chamber was LOX/LH2, and the TAN injection was LOX/Kero. IIRC, they showed that that tripropellant approach actually closed way better than either pure LOX/Kero or pure LOX/LH2 for an SSTO designs -- high thrust and high bulk density for the start, high Isp for the end, and overall a great T/W ratio on the engines in booster mode (especially compared to typical LOX/LH2 engines).

Given that Radian hasn't publicly stated what their engines are using, it's possible they could be doing something clever/unusual like this. Though I kind of think they would've said so if they were, because that would make the whole concept seem more plausible.

~Jon

Maybe they were being guarded while TAN was going off-patent? The basic TAN patent is now open, but were the tripropellant modes free and clear then?

Offline Asteroza

  • Senior Member
  • *****
  • Posts: 2234
  • Liked: 792
  • Likes Given: 29
Re: Radian Crewed SSO Spaceplane
« Reply #124 on: 01/26/2022 02:15 am »
TAV concept had a jet sled launch...

Interesting point is that the flying sled depicted is also a PARWIG when moving from a standing start as well...

Offline HMXHMX

  • Full Member
  • ****
  • Posts: 1686
  • Liked: 2088
  • Likes Given: 631
Re: Radian Crewed SSO Spaceplane
« Reply #125 on: 01/26/2022 03:01 am »
(Although we donít know what theyíre usingÖ if itís hydrolox like X-33, then they will struggle. Itís one of the worst SSTO propellants to use because of its low density.)

I'd caveat that statement re: low density of hydrolox with "when used at normal mixture ratios in normal rocket engines". With LOX-rich TAN, you could theoretically make a stage O/F ratio of 12-18:1 work (instead of the traditional 4-6:1), which would help bulk density a ton, at the cost of lower Isp during the boost phase (which does help lower gravity losses though).

I do agree though that pure LOX/LH2 at traditional mixture ratios has crappier bulk density than you'd want for an SSTO.

When Aerojet did their TAN papers, they also looked at tri-propellant TAN -- where the main chamber was LOX/LH2, and the TAN injection was LOX/Kero. IIRC, they showed that that tripropellant approach actually closed way better than either pure LOX/Kero or pure LOX/LH2 for an SSTO designs -- high thrust and high bulk density for the start, high Isp for the end, and overall a great T/W ratio on the engines in booster mode (especially compared to typical LOX/LH2 engines).

Given that Radian hasn't publicly stated what their engines are using, it's possible they could be doing something clever/unusual like this. Though I kind of think they would've said so if they were, because that would make the whole concept seem more plausible.

~Jon

Maybe they were being guarded while TAN was going off-patent? The basic TAN patent is now open, but were the tripropellant modes free and clear then?


Offline su27k

  • Senior Member
  • *****
  • Posts: 6081
  • Liked: 8651
  • Likes Given: 842
Re: Radian Crewed SSO Spaceplane
« Reply #126 on: 01/26/2022 03:01 am »
As john smith 19 pointed out before, this is quite similar to Boeing RASV, which also uses a sled for takeoff.

Source: https://apps.dtic.mil/sti/citations/ADB216503

Offline HMXHMX

  • Full Member
  • ****
  • Posts: 1686
  • Liked: 2088
  • Likes Given: 631
Re: Radian Crewed SSO Spaceplane
« Reply #127 on: 01/26/2022 03:03 am »
As john smith 19 pointed out before, this is quite similar to Boeing RASV, which also uses a sled for takeoff.

Source: https://apps.dtic.mil/sti/citations/ADB216503

Offline libra

  • Full Member
  • ****
  • Posts: 1820
  • Liked: 1201
  • Likes Given: 2359
Re: Radian Crewed SSO Spaceplane
« Reply #128 on: 01/26/2022 06:09 am »
Ah sure, if they got the TAN way then it makes their SSTO endeavour a bit more convincing. A decade ago Melvin Bulman at Aerojet had an extremely promising concept he called "Variable Element Launcher". It was a paradigm change for SSTOs.

The smart trick was to add kerosene fuel (or hydrogen fuel) into the exhaust, rather that in the combustion chamber (as done by Salkeld and Beichel and also MAKS RD-701).
Put otherwise: a rocket AFTERBURNER, rather than tweaking the injectors inside the combustion chambers.

Going tripropellant, yes - but at the nozzle, somewhat. Well that's very clever, as it avoids the need for different injectors and different combustion chambers; as kerosene and hydrogen densities and temperatures are so different (room temperature versus -269įC, 0.8 vs 0.25 density).
« Last Edit: 01/27/2022 07:16 am by libra »

Offline Halken

  • Member
  • Posts: 25
  • Denmark
  • Liked: 16
  • Likes Given: 9
Re: Radian Crewed SSO Spaceplane
« Reply #129 on: 02/02/2022 02:59 pm »
Would they win something if they combined it with a ramjet/scramjet engine - also on the way back?

Also, why not make two variants, one unmanned cargo version and one manned. Starting with a manned version makes it more complicated and shaves off the margins.
« Last Edit: 02/02/2022 08:40 pm by Halken »

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 36158
  • Minnesota
  • Liked: 20513
  • Likes Given: 10636
Re: Radian Crewed SSO Spaceplane
« Reply #130 on: 02/10/2022 03:42 pm »
Would they win something if they combined it with a ramjet/scramjet engine - also on the way back?

Also, why not make two variants, one unmanned cargo version and one manned. Starting with a manned version makes it more complicated and shaves off the margins.
Well maybe. The argument by XCOR and others is that itís easier to get flight approval for a crewed experimental aircraft than a drone, which is true in some senses (but perhaps not in others).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 36158
  • Minnesota
  • Liked: 20513
  • Likes Given: 10636
Re: Radian Crewed SSO Spaceplane
« Reply #131 on: 02/10/2022 03:56 pm »
Also, uncrewed launch is kind of a saturated market right now.

Uncrewed launch with vehicles flying* or with hardware and within a couple years of launch:
SpaceX (Falcon 9, Heavy, Starship)*
Antares (NG)*
ULA (Atlas, Delta, Vulcan)*
Blue Origin (new Glenn)*ish
Rocketlab (electron, Neutron)*
VirginOrbit*
Astra*
Firefly*ish
ABL
Relativity
and others (SLS? launcher?)

Thatís just in the US.

Crewed orbital launch, currently flying:
SpaceX. Thatís it.

In the future:
Orion and Boeing are not far, but theyíll likely be too expensive for real commercial uses.
Maybe Dream Chaser.

So the list of orbital crewed launch is much smaller. And the revenue for crewed launch might be more than the whole smallsat launcher industry, so I donít think itís something to ignore.

Enables satellite servicing and space tourism markets while also giving a possibility of those lucrative NASA crew contracts, which could be over a billion dollars per year (thatís like hundreds of micro/smallsat launchesí worth).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Halken

  • Member
  • Posts: 25
  • Denmark
  • Liked: 16
  • Likes Given: 9
Re: Radian Crewed SSO Spaceplane
« Reply #132 on: 02/14/2022 05:46 pm »
Also, uncrewed launch is kind of a saturated market right now.

Uncrewed launch with vehicles flying* or with hardware and within a couple years of launch:
SpaceX (Falcon 9, Heavy, Starship)*
Antares (NG)*
ULA (Atlas, Delta, Vulcan)*
Blue Origin (new Glenn)*ish
Rocketlab (electron, Neutron)*
VirginOrbit*
Astra*
Firefly*ish
ABL
Relativity
and others (SLS? launcher?)

Thatís just in the US.

Crewed orbital launch, currently flying:
SpaceX. Thatís it.

In the future:
Orion and Boeing are not far, but theyíll likely be too expensive for real commercial uses.
Maybe Dream Chaser.

So the list of orbital crewed launch is much smaller. And the revenue for crewed launch might be more than the whole smallsat launcher industry, so I donít think itís something to ignore.

Enables satellite servicing and space tourism markets while also giving a possibility of those lucrative NASA crew contracts, which could be over a billion dollars per year (thatís like hundreds of micro/smallsat launchesí worth).

Sounds a bit weird with the license, as something that carries humans need a lot more safety. That is also why I suggest the design for carrying humans, but that they should get it working first without humans, as it would make it cheaper to develop. A human-rated launch system is more complicated, expensive and requires more documentation, so it would aim to reduce the risk and investment needed. As they learn and reach the milestones, they can add complexity. SpaceX did not start with a reusable rocket, but a very basic and simple one and then improved from there. Walk before you can run and make it so simple as you can, while still proving the concept.

How using them SCRAM jet engines for such a thing? I kind of like the idea that they give more freedom on the way down as a maybe a push on the way up?

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 9856
  • Everyplaceelse
  • Liked: 2292
  • Likes Given: 12754
Re: Radian Crewed SSO Spaceplane
« Reply #133 on: 08/07/2022 09:45 am »
I've been offline for some time but I did crunch some numbers for this.

Aircraft don't really seem to have a "mass fraction" but they do have a "Fuel fraction" AFAIK the best of these ws for the Virgin Atlantic Global Flyer which Steve Fossett used to circumnavigate the world. It was built  by Scaled Composites who also beat the previous 2 person aircraft to do this flight, Voyager.
The GF had very low stress margins, a very low thrust to weight ratio and a cruise speed of about M0.5 (roughly 1/46 of orbital velocity at 200Km), so no transonic buffeting or drag rise to deal with. Not having to cope with re-entry heating helped the mass as well, as did no major concessions for repair/maintain/oper-ability. Basically a 1 flight and done aircraft.

Voyager had a fuel fraction of 72%. With more than a decade more experience SC got the GF up to 86%.

So arguably the best design/build team in the industry for one-off aircraft, lead by a designer who'd spent his lifetime acquiring (and using) the best techniques for composite construction available gets you a design that packs everything into 14% of GTOW

Let's suppose however that between the sled launch and the wings aerodynamic lift all launch losses are cancelled. So all you need to work out the mission is to dial in the altitude, subtract sled speed at seperation, and that's the target delta V.

So at 200Km that's 7785m/s. Assume the sled removes 200m/s that leaves 7585m/s. Using Dunns figure for Methalox of 368.3sec using a 20MPa (2900Psi) chamber pressure and 100:1 expansion ratio and run the rocket equation.
This gives a structural fraction (for everything, vehicle, landing gear, all payload) of 12.25%

That's 1.75% below the best ever achieved structural fraction for a winged vehicle.

Rerunning the calculation with Dunns value for LH2 gives you 18.34%.

And we haven't discussed the mass of the escape pod or the TPS yet.  :(

There really is Hydrogen and everything else. :( Boeing really did know what they were talking about when they designed RASV. The implication of this (which a freshman aeronautical engineering student should have been competent to do) are.

a)That Radian have acquired (or developed) in total secrecy a structural architecture that makes much more efficient use of existing materials, or they have developed structural materials that are radically better than CFRP, or any other known materials*. Such a development would be a major breakthrough and would be valuable IP, and would truly be "disruptive."
The patent makes no reference to any such material or technique.
Of course they may be choosing to show off that aspect of the design with investors without making any public references to it, although I've never seen any other startups I'm aware of do this.

or

b) The design is total BS.

 I had always thought the X33 failed due to LM's over-promising undercooked technology and staffing the programme with b-team engineering talent to ensure failure. I had never considered the possibility that they also selected a project leader who belief in themself could have vastly outstripped their ability to execute.  :(

I'll need to update my ways-to-guarantee-project-failure list.  :(

Time will tell which one of these PoV's is accurate.

*My Buzzword Bingo Generator (Materials Science Edition TM) came up with "Boron reinforced Magnesium Beryllium alloy"**
**Mg5Be was looked at in the Soviet Union in the 60's as a higher temperature cladding for Uranium metal fuel in CO2 cooled reactors. An upgrade from Magnox alloys.
« Last Edit: 08/08/2022 04:33 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022. Forward looking statements. T&C apply. "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap

Offline Halken

  • Member
  • Posts: 25
  • Denmark
  • Liked: 16
  • Likes Given: 9
Re: Radian Crewed SSO Spaceplane
« Reply #134 on: 09/26/2022 01:59 pm »
@JS

They may have other IP that is not mentioned in the patent, as when a patent is filed, they have 16 years to exercise it. So keeping it as a trade secret may be a better strategy depending on how long time they estimate it will take to develop. They have raised some money, so external parties have likely done some due diligence on the concept.

Did the shuttle have an escape pod?

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 9856
  • Everyplaceelse
  • Liked: 2292
  • Likes Given: 12754
Re: Radian Crewed SSO Spaceplane
« Reply #135 on: 09/26/2022 02:22 pm »
@JS

They may have other IP that is not mentioned in the patent, as when a patent is filed, they have 16 years to exercise it. So keeping it as a trade secret may be a better strategy depending on how long time they estimate it will take to develop. They have raised some money, so external parties have likely done some due diligence on the concept.
Quite possibly. Time will tell what they have, or don't have.
Quote from: Halken
Did the shuttle have an escape pod?


No. Shuttle did not have an escape pod. It's design was supposed to be good enough that the failure rate would be below the total num ber of  flights during the life of the programme, at least that's what senior management wanted.  :(

As I noted the best fuel fractional aircraft I could find managed 84%. If you play around with my design game XLS you'll see that's still not good enough, hence my extreme scepticism that this is going to go anywhere.

Escape pods add lots of mass. Unfortunately the only examples date from the days of mechanical, or semi-mechanical controls IE the B1. A modern system would use fly-by-wire, which would radically lower mass, for example separtion becomes disconnecting a plug and socket, versus  pyrotechnic powered guillotine.
OTOH it's likely to need to operate to a much higher altitude than previous systems, so bigger parachutes, possible TPS etc.

Anyone thinking about this needs to recall Ed Heinman's advice to "Simplicate, and add lightness."
Such a pod is likely to need a)Parachutes b)seperation rocket motors c)Floation aids.
The lighter the pod a,b&c have to deal with the easier the design task. That means strip anything not absolutely essential out of the pod and put it in the vehicle itself. This is a civilian vehicle, not military. All that should be in the pod is (effectivley) the UI for the various systems. The systems themselves (ECLSS,propellant, propulsion, landing et) are outside the pod walls, except for any fluid connections, like airflow.

Also note that 5 of the 6 people are passengers. They have no equipment/weapons to monitor. They need even less equipment than the pilot.  :(
« Last Edit: 09/26/2022 02:22 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022. Forward looking statements. T&C apply. "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap

Offline Halken

  • Member
  • Posts: 25
  • Denmark
  • Liked: 16
  • Likes Given: 9
Re: Radian Crewed SSO Spaceplane
« Reply #136 on: 10/03/2022 07:38 am »
@JS

Yes, we have to wait and see if they have more to show.

If it's a plane, can they then forego the escape capsule as they can glide back to earth unpowered, unlike a rocket?

You assumed they got to 200 km/h with the sled? Would it not be possible to move that to 400 km/h and would that make any difference?

They are working on the marginals I believe and since they have raised that kind of money and attracted astronauts they must have found a way where the marginals are enough in their favor. If it was easy everyone would do it.

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 9856
  • Everyplaceelse
  • Liked: 2292
  • Likes Given: 12754
Re: Radian Crewed SSO Spaceplane
« Reply #137 on: 10/03/2022 09:03 am »
If it's a plane, can they then forego the escape capsule as they can glide back to earth unpowered, unlike a rocket?
Historically most danger in rocket launch is actually at launch. They could scrap the escape module plan if they felt their vehicle is safer than expendables.
Quote from: Halken
You assumed they got to 200 km/h with the sled? Would it not be possible to move that to 400 km/h and would that make any difference?
No I assumed they got 200 metres per second from the sled. The speed of sound at ground level is 340m/s
You can use the design game earlier in the thread to see what happens if you increase the takeoff speed right up to the speed of sound at ground level. That would produce a very loud sonic bang at ground level that would likely be heard for 10s of miles.
Quote from: Halken
They are working on the marginals I believe and since they have raised that kind of money and attracted astronauts they must have found a way where the marginals are enough in their favor. If it was easy everyone would do it.
It's not that much money for the task and I think it's mostly from investors who really want to do something without doing much in the way of due dilligence. 
If they had they'd have realized that the switch from LH2 (like RASV) to kero has major implications on implementability.

If they really have something then they will raise enough funds to execute something or license it to someone. Either will trigger product announcements or PR.

If they have nothing then the company will just disappear like so many before it.  :(

I have no special insight into them and I'm just going by their public statements. If they have been more forthcoming to their investors then they may have more reason to be optimistic. Based on their public statements this thing won't fly.  I could not find an aircraft that had the fuel fraction necessary to make this design possible.

That's not to say it's impossible, but it was beyond what IMHO is one of the most skilled CFRP design and build teams in the aircraft industry can manage. On a side note what the SABRE engine gives Reaction Engines is to build a winged vehicle at a structural fraction that is possible.  In effect SABRE allows you to afford to fit wings to a vehicle.

Do you have some special investment in Radian? You seem quite invested in their success.
« Last Edit: 10/05/2022 07:40 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022. Forward looking statements. T&C apply. "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap

Tags:
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0