Flyback booster: Land in Africa, mount jets

In another thread, flyback boosters with jet engines were mentioned.

Why do they keep including these jet engines before launch ?

They have no function until the flyback.

So dimension the craft, so the booster lands in Africa.

Mount the jet engines there, plus perhaps an extra set of wings, then
refuel and fly back.

Come to think about it: For recoverable 1. stages of the ROMBUS style
type, again land in Africa after sending 2. stage on it's way.

Fit a new nose cone, refuel and fly back.

That's my idea of a fly back booster.

Both ideas allow for vehicle check out before returning, and you avoid
designing ships or special planes to retrieve.

Come to think about it, how about landing in Africa, mount another 2.
stage + payload, and land in ??? I've got to check out if there is a
place to land and launch the 3. time. And perhaps the 4. time, landing
at KSC.

Regards

Carsten Nielsen
Denmark

"Carsten Nielsen" wrote ...
In another thread, flyback boosters with jet engines were mentioned.

Why do they keep including these jet engines before launch ?

They have no function until the flyback.

Er, avoiding that nasty 'crunch' sound as the boosters land without
parachutes?

(Carsten Nielsen) writes:

In another thread, flyback boosters with jet engines were mentioned.

Why do they keep including these jet engines before launch ?

They have no function until the flyback.

Sure they do. They allow routine landings of the boosters at landing
strips. Without these engines, you're stuck with glider landings that
are more dangerous. With engines, you can do a "go around" if your
first approach looks bad. With a glider, you don't have that option.

Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.

This idea that the booster comes down far east of where it lifted off,
makes good sense to me. Here's an example of thinking outside the
conventional box. To return to near the launch pad seems to require
much more delta v than to keep going and come down somewere east of
liftoff.

I picture several of these boosters, each circling the world in 3 or 4
hops, serving different countries programs along the way.

That is, assuming Bush doesn't kill serious space exploration, as I
fear he's up to. If you look at his extremist Christian background,
you may conclude as I do that he's a closet millennialist and will
choose to spend max dollars on military programs and preparation for
the expected rapture.

Cheers -- Martha Adams

Carsten Nielsen wrote:

In another thread, flyback boosters with jet engines were mentioned.

Why do they keep including these jet engines before launch ?

They have no function until the flyback.

So dimension the craft, so the booster lands in Africa.

Mount the jet engines there, plus perhaps an extra set of wings, then
refuel and fly back.

Come to think about it: For recoverable 1. stages of the ROMBUS style
type, again land in Africa after sending 2. stage on it's way.

This would severely limit delta-V and inclination flexibility. And you might
have political problems. At the very least you must include a few 100
million $ anually in bribes to secure a politically stable landing zone.

Fit a new nose cone, refuel and fly back.

That's my idea of a fly back booster.

Both ideas allow for vehicle check out before returning, and you avoid
designing ships or special planes to retrieve.

What is wrong with using a ship as a means for landing and retrieval?

Modifying existing ships with a start and landing area for a VTVL booster
stage should be easy and cheap. You have a lot of flexibility choosing the
inclination of your orbit and the delta-V provided by the booster, and the
ship can be used to check out and refuel the booster while bringing it back
to the launch site. With a hop of 2000km and a ship speed of 40kph you
could have a launch every 2 days, and free choice of inclination. If there
is an accident and your booster misses the landing area, it splashes into
the sea harmlessly and maybe it can even be refurbished.

Come to think about it, how about landing in Africa, mount another 2.
stage + payload, and land in ??? I've got to check out if there is a
place to land and launch the 3. time. And perhaps the 4. time, landing
at KSC.

That gives you three potentially unstable regimes to worry about. And you
have to have four payloads ready before starting a round trip. Given the
difficulties arianespace have with dual sattelite lauches, this seems like
a bad idea.

regards,

Rüdiger Klaehn

In article ,
Martha H Adams wrote:
This idea that the booster comes down far east of where it lifted off,
makes good sense to me. Here's an example of thinking outside the
conventional box. To return to near the launch pad seems to require
much more delta v than to keep going and come down somewere east of
liftoff.

Unfortunately, "somewhere east" tends to be hundreds, not thousands, of
kilometers even for quite aggressive first stages.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

(Carsten Nielsen) wrote in message . com...
In another thread, flyback boosters with jet engines were mentioned.

Why do they keep including these jet engines before launch ?

They have no function until the flyback.

So dimension the craft, so the booster lands in Africa.

Mount the jet engines there, plus perhaps an extra set of wings, then
refuel and fly back.


Most booster stages don't fly nearly that far downrange.
It would be more reasonable to have the boosters do a
bit of crossrange and land on a Bahamian island, for
launches to 28.5 degree inclinations at least. For ISS
inclination launches, a booster might have to land in
Georgia or the Carolina's.

How about this idea? Rather than fit jet engines to a
landed booster stage, why not fill it with its original
propellants and use its rocket engines to "fly back"?
Or, to lower costs, just float it back on a ship.

- Ed Kyle

Joann Evans wrote

Carsten Nielsen wrote:

In another thread, flyback boosters with jet engines were mentioned.

Why do they keep including these jet engines before launch ?

They have no function until the flyback.

So dimension the craft, so the booster lands in Africa.

Mount the jet engines there, plus perhaps an extra set of wings, then
refuel and fly back.

Come to think about it: For recoverable 1. stages of the ROMBUS style
type, again land in Africa after sending 2. stage on it's way.

Fit a new nose cone, refuel and fly back.

That's my idea of a fly back booster.

Both ideas allow for vehicle check out before returning, and you avoid
designing ships or special planes to retrieve.

Come to think about it, how about landing in Africa, mount another 2.
stage + payload, and land in ??? I've got to check out if there is a
place to land and launch the 3. time. And perhaps the 4. time, landing
at KSC.

Regards

Carsten Nielsen
Denmark


One prefers to have jets on a flyback booster so as to make a more
conventional, powered landing, including the ability to 'go-around' if
necessary. You really don't want to do glider landings all the time if
you don't have to. And being a TSTO, you likely can spare the mass for
this on the first stage.


The Finial manned winged jet/rocket hybrid flyback booster takes off from an
ordinary airfield and flies 430 km west on jet engines, climbing to 10km on
the way. Then it turns round and accelerates eastwards and upwards, using
first air-breathing and later rocket power. The 70 tons of jet fuel used in
the flight west is not accelerated during the rocket burn, so it's cheap to
carry.

Separation occurs at 100 km altitude, near-zero vertical and 1800 m/s
horizontal velocity, still 240 km west of takeoff. The flyback booster then
re-enters the atmosphere and slows down, at which point it is back above the
takeoff field. It still has 15 tons of jet fuel on board for emergencies and
go-arounds etc.

--
Peter Fairbrother

Henry Spencer wrote:
Unfortunately, "somewhere east" tends to be hundreds, not thousands,
of kilometers even for quite aggressive first stages.

Would Bermuda be a possibility?
--
Keith F. Lynch - http://keithlynch.net/
Please see http://keithlynch.net/email.html before emailing me.

Joann Evans wrote

Peter Fairbrother wrote:

The Finial manned winged jet/rocket hybrid flyback booster takes off from an
ordinary airfield and flies 430 km west on jet engines, climbing to 10km on
the way. Then it turns round and accelerates eastwards and upwards, using
first air-breathing and later rocket power. The 70 tons of jet fuel used in
the flight west is not accelerated during the rocket burn, so it's cheap to
carry.

Separation occurs at 100 km altitude, near-zero vertical and 1800 m/s
horizontal velocity, still 240 km west of takeoff. The flyback booster then
re-enters the atmosphere and slows down, at which point it is back above the
takeoff field. It still has 15 tons of jet fuel on board for emergencies and
go-arounds etc.



If this is primairily a rocket, one will not be in a regieme for very
long, where jet engines would be useful.

Nope, it's a piloted combined jet aircraft and rocket first stage.

Likely not enough to burn 70
tons of fuel, though others can probably comment on this better than I.

It uses 70 tons because it faffs around as a jet aircraft for a bit before
it starts using its rockets. During this faffing around it travels west
before starting its rockets, so that when its rocket flight is over and it's
time to land then it's back near its take-off point.

Rockets are best operated on trajectories that get out of the lower
atmosphere (and its attendant drag/heating) as quickly as reasonably
possible.

Agreed. But Finial doesn't use rockets to get out of the lower atmosphere,
it uses jets and wings. It uses them again when it's landing. Once it's out
of the lower atmosphere it uses rockets, but not before.

That's why there are very few VTLV SSTO designs that use air
breathing. (The Synerjet being the only exception that I know.) They
don't even pretend to be in horizontal atmospheric cruise, the very
opposite of airbreathing hypersonic spaceplane concepts.

It is a VTVL TSTO first stage. SSTO is hard, which makes it too expensive
imo. It's not a hypersonic airbreather. It's entirely subsonic as an
airbreather.

It starts off as a jet aircraft, with wings, burning 70 tons JP-4 to get to
10 km high and mach 0.8, then it starts operating as a rocket, burning 190
tons of LOX/RP-1, reaching 100 km altitude and 1800 m/s horizontal after a
coast. There is a LOX/LH2 second stage.

It could be a bit Synerjet-ty if you like, because the bits (air intakes and
the like) are already there. It doesn't need to be though. BTW was there an
actual Synerjet, or is it just a generic name?

You could look at it as a three stager - the first stage is a jet aircraft
air-launcher, the second stage is a LOX/kero rocket, and the third stage is
a LOX/LH2 rocket. Except that the first stage and the second stage are
combined in one reuseable machine.

The only new tech is the reuseable rocket engines. It's generously
specified, there are no hard-to-achieve targets. Flight rate is 6 flights
per day. GLOW 440 tons, payload 10 tons to LEO.


Why combine the first two stages? So that a) you aren't dropping any used
tanks, motors, etc anywhere, everything stays together under a pilot's
control or goes into orbit; b) everything* is reused except fuel; c) you
only need one airfield to take off from and land at - you can take-off twice
in 90 minutes; d) it's safer, the second stage is just another aircraft
rather than an unpiloted falling hunk of metal e) it costs less to develop
and build than two separate stages;

and lastly, and most important f) it's not as extravagant as you might think
carrying all those useless jet engines and wings and landing gear during the
LOX/kero burn - and you'll need them later.

* even the helium used for tank pressurisation and insulation is recovered.


--
Peter Fairbrother