SpaceX fully reusable launcher
byblow
fully reusable, two-stage launcher. In this SpaceX animated video --
http://www.youtube.com/watch?v=p176UpWQOs4 -- the launcher reminds me
of the Falcon 9; it looks like the first stage has nine engines.
I would think SpaceX would need a much more capable launcher, perhaps
something more like the Falcon X or Falcon XX (sans its NERVA-based
NTR, for political reasons) to get a decent payload and have enough
fuel for a tail-first, soft landing.
Would a LOX-kerosene first stage provide enough capability for such a
launcher, or would SpaceX have to switch to a LOX-LH2 first stage?
Musk made a comment about reusing such a launcher 1,000 times. Was he
just stirring up interest, or could a tail-first, soft landing make it
possible to reuse a launcher 1,000 times?
Robert Heller
>
> I would love to hear opinions about Elon Musk's announcement re: a
> fully reusable, two-stage launcher. In this SpaceX animated video --
> http://www.youtube.com/watch?v=p176UpWQOs4 -- the launcher reminds me
> of the Falcon 9; it looks like the first stage has nine engines.
>
> I would think SpaceX would need a much more capable launcher, perhaps
> something more like the Falcon X or Falcon XX (sans its NERVA-based
> NTR, for political reasons) to get a decent payload and have enough
> fuel for a tail-first, soft landing.
>
> Would a LOX-kerosene first stage provide enough capability for such a
> launcher, or would SpaceX have to switch to a LOX-LH2 first stage?
able to send the Applo missions to the moon...
>
> Musk made a comment about reusing such a launcher 1,000 times. Was he
> just stirring up interest, or could a tail-first, soft landing make it
> possible to reuse a launcher 1,000 times?
>
>
Robert Heller -- 978-544-6933 / hel...@deepsoft.com
Deepwoods Software -- http://www.deepsoft.com/
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Jorge R. Frank
> At Sat, 1 Oct 2011 08:17:56 EDT byblow<pstu...@gmail.com> wrote:
>
>>
>> I would love to hear opinions about Elon Musk's announcement re: a
>> fully reusable, two-stage launcher. In this SpaceX animated video --
>> http://www.youtube.com/watch?v=p176UpWQOs4 -- the launcher reminds me
>> of the Falcon 9; it looks like the first stage has nine engines.
>>
>> I would think SpaceX would need a much more capable launcher, perhaps
>> something more like the Falcon X or Falcon XX (sans its NERVA-based
>> NTR, for political reasons) to get a decent payload and have enough
>> fuel for a tail-first, soft landing.
>>
>> Would a LOX-kerosene first stage provide enough capability for such a
>> launcher, or would SpaceX have to switch to a LOX-LH2 first stage?
>
> You do know that the Saturn 5 first stage was LOX-kerosene, and it was
> able to send the Applo missions to the moon...
Dr J R Stockton
qe.googlegroups.com>, Sat, 1 Oct 2011 08:17:56, byblow
<pstu...@gmail.com> posted:
>I would love to hear opinions about Elon Musk's announcement re: a
>fully reusable, two-stage launcher. In this SpaceX animated video --
>http://www.youtube.com/watch?v=p176UpWQOs4 -- the launcher reminds me
>of the Falcon 9; it looks like the first stage has nine engines.
>
>I would think SpaceX would need a much more capable launcher, perhaps
>something more like the Falcon X or Falcon XX (sans its NERVA-based
>NTR, for political reasons) to get a decent payload and have enough
>fuel for a tail-first, soft landing.
The current Falcon 9 will do about 10 tonnes to LEO, 5 tonnes to GTO,
and the LEO price is of the order of $30M. Wikipedia figures.
If they get just 10 flights per F9, but 1/2 the payload, the cost per go
should be well under $10M (allowing for fuel, servicing, staff costs,
etc.). That looks a price worth designing payloads for. Figures are
pure guesses.
BTW, the Video did not, as far as I recall, say that the second stage
would flu back; the obvious route is once around Earth. And I think EM
said that the video was not faithful to all planned detail.
--
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Web <http://www.merlyn.demon.co.uk/> - FAQqish topics, acronyms and links;
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dglow
byblow;1177930 Wrote:
> I would love to hear opinions about Elon Musk's announcement a
> http://www.youtube.com/watch?v=p176UpWQOs4 -- the launcher reminds me
> of the Falcon 9; it looks like the first stage has nine engines.
>
awe-inspiring. I'm sure many rocket experts have already dissected it
frame-by-frame, but I've found no such discussions online. Perhaps that
can begin here... :)
For my part, a few layman's observations and questions:
First Stage:
- Yes, it looks a lot like Falcon 9, byblow. SpaceX says they're all
about economies of scale, so I guess it's no surprise this appears to be
an evolutionary design.
- It's nice how the landing gear fold into aerodynamic nacelles and tuck
against the body for launch.
- Is there an ablative surface on the front of the first stage? The
video doesn't show this clearly. However, after separation the second
stage appears to fire against the first stage as it departs. A clever
way of conserving energy and saving fuel?
- What happens to the black interstage element between separation and
landing? Does it retract into the body somehow?
Second stage:
- Look at how the rocket nozzle both emerges from and contracts into the
body, with the landing gear rocking in and out to provide clearance -
very clever.
- The ablative surface is asymmetrical, with more of it on one side.
That means there's only one good orientation for re-entry, yes?
- Will the ablative surface pose any difficulties for mating the payload
atop it?
- After the re-entry burn we don't see the main rocket firing again; as
the stage touches down we only see small, side-rockets firing. Any
thoughts as to what's going on here?
Dragon:
- Do we see anything which hasn't been shown in previous videos? It
doesn't appear so, but perhaps I'm missing something.
- What is the small surface, shown at the 'top' of Dragon, which folds
down prior to ISS docking?
Wow, so much going on here. Somebody please help me out: for SpaceX to
pull this off, are they banking on using atmospheric oxygen for the
propulsive landings? It seems doing so could save a great deal of
weight, but... is such an approach readily possible? Do there exist
rocket engines with the ability to switch from LOX to air-derived O2?
--
dglow
Keith Henson
snip
> Do there exist
> rocket engines with the ability to switch from LOX to air-derived O2?
The proposed SABRE engines for the Skylon make the switch from air to
LOX so I suppose they could do the opposite.
Musk isn't a fan of space based solar power, but he does seem to be
trying to get the lift cost down into the range where SBSP makes sense
(100/kg to GEO).
Some years ago I came to the conclusion that even LOX/LH2 isn't good
enough and think it will take the exhaust velocity you can get from
beamed energy to get the cost down.
NASA does have a small project starting up that will investigate
hydrogen skin heaters to around 10 MW/m^2.
Keith Henson
byblow
show a a nose-first reentry for the first-stage, but as dglow astutely
noticed, the front of the first-stage appears to have a heat shield
that can handle the second-stage exhaust at separation.
After separation, the first stage flips over and fires three of its
nine engines to begin reentry (I wonder what altitude the stage will
reach?). It's next shown descending tail first, possibly with just the
center engine firing. The landing struts begin to deploy, rotating
downward from a 12 o'clock position, to roughly 5 o'clock and 7
o'clock positions by touchdown. The landing struts appear rather wide,
perhaps for extra drag during final descent. I wonder if they're
thinking about using aerodynamic flaps as well?
My guess is the first-stage does a nose-first reentry like the second-
stage, flips over and goes into free fall during most of its descent
through the atmosphere, perhaps using the RCS at the top of the stage
to control its attitude. I'm curious about what altitude SpaceX
envisions firing the center engine for final descent and landing. I
assume only one engine is needed because most of its fuel is spent,
and the second-stage and Dragon are absent.
The Wiki article about the DC-X notes that if it could reach orbit, it
would make an ideal craft for landing on the moon or Mars, the latter
of which is Musk's ultimate goal. Perhaps he has visions of using the
second stage as a Mars cargo lander to complement the Dragon-derived
Mars people lander. He might need a fuel depot in earth orbit for
such a scheme.
Wiki: "Had a DC-type craft been developed that operated as an SSTO in
Earth's gravity well, even if with only a minimum 4-6 crew capacity,
variants of it might prove extremely capable for both Mars and Moon
missions. Such a variant's basic operation would have to be
"reversed"; from taking off and then landing, to landing first then
taking off. Yet, if this could be accomplished on Earth, the weaker
gravity found at both Mars and the Moon would make for dramatically
greater payload capabilities, particularly at the latter destination."
Ed Kyle
> My guess is the first-stage does a nose-first reentry like the second-
> stage, flips over and goes into free fall during most of its descent
> through the atmosphere, perhaps using the RCS at the top of the stage
> to control its attitude. I'm curious about what altitude SpaceX
> envisions firing the center engine for final descent and landing. I
> assume only one engine is needed because most of its fuel is spent,
> and the second-stage and Dragon are absent.
>
velocity, which would have to occur *before reentry*. The intent
would be to reduce reentry heating, which has destroyed all of the
Falcon stages launched to date, by reducing velocity at the "entry
interface" (or whatever they call it). This requires the engines to
fire well before reentry, probably even before apogee, which would
mean starting them not long after staging. I'm just guessing
though ....
- Ed Kyle
www.spacelaunchreport.com
byblow
Would anyone care to venture a guess as to how much a fully reusable
launcher -- based on a Falcon 9 -- could place in LEO?
How about a fully reusable launcher with fully reusable side boosters?
If cross-feed were used, would that result in the first-stage core
booster going too high for the heat shield currently envisioned to
protect it during descent?
dglow
you to believe its first-stage core achieves a greater altitude than the
standard Falcon 9?
--
dglow
Jeff Findley
@de2g2000vbb.googlegroups.com>, pstu...@gmail.com says...
> Would anyone care to venture a guess as to how much a fully reusable
> launcher -- based on a Falcon 9 -- could place in LEO?
equal. SpaceX is working on a more efficient Merlin engine for Falcon
9, which would help offset any payload "penalty" caused by adding
hardware, propellants, and etc. needed for recovery.
> How about a fully reusable launcher with fully reusable side boosters?
> If cross-feed were used, would that result in the first-stage core
> booster going too high for the heat shield currently envisioned to
> protect it during descent?
completely open about how they intend to recover the first stage of
Falcon 9, so any extrapolation to the core of Falcon Heavy is pure
conjecture at this point in time.
Jeff
--
" Ares 1 is a prime example of the fact that NASA just can't get it
up anymore... and when they can, it doesn't stay up long. ;) "
- tinker
byblow
I thought I read somewhere that by the time the side boosters on the
Falcon Heavy drop away, the core first-stage is almost full because of
the cross feed going on with the side boosters. If it's close to full
when the side boosters separate, I assume it would go higher before
second-stage separation than the Falcon 9 first-stage. I could most
definitely be wrong though ;-)
David Spain
> At Sat, 1 Oct 2011 08:17:56 EDT byblow <pstu...@gmail.com> wrote:
>
>> I would love to hear opinions about Elon Musk's announcement re: a
>> fully reusable, two-stage launcher. In this SpaceX animated video --
>> http://www.youtube.com/watch?v=p176UpWQOs4 -- the launcher reminds me
>> of the Falcon 9; it looks like the first stage has nine engines.
down") that doesn't require response moderation. For my opinions on this look
there.
Dave