Elon Musk's SpaceX to build 'Grasshopper' hover-rocket

On 2/10/2011 7:29 PM, Mike DiCenso wrote:
On Oct 1, 10:16 pm, Alan wrote:
On 30/09/2011 7:09 AM, wrote:
You mean the Boeing idea for the shuttle (if I remember correctly, it
involved four boosters, two on each side of the ET)?

Actually, that system was two big LOX/Kerosene boosters that were
supposed to be powered by surplus F-1As
that had been intended for use on the Saturn V, but were never used
despite being built and certified.
-Mike

To answer your question, the foam was dislodged by vibration from the
SRB, not just aerodynamic forces.

As for the boosters, I remember seeing drawings a couple of years ago of
a shuttle booster about to land on the skid strip at the Cape. It was a
Boeing project, but I hadn't heard they were going to use surplus F1
engines.

On Fri, 30 Sep 2011 10:00:03 -0400, Jeff Findley
wrote:

Falcon Heavy's LEO payload capacity is 117,000 lb (53 metric tons).
Even if making a Falcon Heavy reusable ate up 1/2 of the payload, it
would still be capable of putting more payload into orbit than the space
shuttle.

But they will probably run into problems making Falcon Heavy fully
reusable. If they're crossfeeding propellant from the strap-ons to the
core, the core will be too high/too fast/too far to turn around and
fly back to the Cape, but not high enough/fast enough/far enough to
reach a landing site in Europe or Africa. An ECAL-like landing in New
England or Newfoundland might be possible, but only for
high-inclination launches. The no man's land point will begin
somewhere around 4 minutes into flight, where Shuttle used to get the
"negative return" call.

Brian

On Sun, 2 Oct 2011 01:26:11 -0700 (PDT), Mike DiCenso
wrote:

Assuming they can get this to work, of course. It's an interesting
concept, to be sure. Good luck to Lord Musk-he's gonna need it. (and
no, he's not the Messiah when it comes to HSF-which a lot of folks,
especially those on spacepolitics.com, seem to think)- Hide quoted text -

What this reminds me of, ironically enough, is the recovery system
for the now defunct Kistler K-1 reusable rocket, minus the three
parachutes and landing airbags.

I wonder if SpaceX could license ROTON technology...

Brian

On Sun, 02 Oct 2011 16:16:09 +1100, Alan Erskine
wrote:

On 30/09/2011 7:09 AM, wrote:
Whatever happened to the "Glide Back" booster proposals that
would allow the booster to fly downrange, as well as vertically,
and still be able to return to the launch site?

You mean the Boeing idea for the shuttle (if I remember correctly, it
involved four boosters, two on each side of the ET)? One word for you -
cost. Nobody wanted to add any more cost to the shuttle program.
However, if they had, it might have saved Columbia and its crew.

It was first called Liquid Flyback Booster and was later renamed
Reusable First Stage. They looked at many configurations, including
four boosters and a single catamaran booster, but were down to two
boosters per launch before the concept was shelved. F-1 wasn't exactly
a gentle engine, so I doubt they would have saved the Columbia crew.

Brian

A couple of suggestions for the reusable version of the Falcon 9.
First, model it on the DC-X. In the SpaceX video of the proposed
reusable launcher the first and second stages have the same straight
sides of the expendable versions. But having sloping sides helps to
protect the sides of the vehicle during reentry as well as increasing
aerodynamic stability during reentry.
Note that as long as the cross-section remains circular for a conical
shaped stage you should still get the high tankage ratio that obtains
for cylindrical tanks:

Space Access Update #91 2/7/00.
The Last Five Years: NASA Gets Handed The Ball, And Drops It.
"...part of L-M X-33's weight growth was the "multi-
lobed" propellant tanks growing considerably heavier than promised.
Neither Rockwell nor McDonnell-Douglas bid these; both used proven
circular-section tanks. X-33's graphite-epoxy "multi-lobed" liquid
hydrogen tanks have ended up over twice as heavy relative to the
weight of propellant carried as the Shuttle's 70's vintage aluminum
circular-section tanks - yet an X-33 tank still split open in test
last fall. Going over to aluminum will make the problem worse; X-
33's aluminum multi-lobed liquid oxygen tank is nearly four times as
heavy relative to the weight of propellant carried as Shuttle's
aluminum circular-section equivalent."
http://www.space-access.org/updates/sau91.html

The McDonnell-Douglas version mentioned there was the scaled up DC-X.
There are a couple of ways this DC-X styled Falcon 9 could be
implemented. As this is to be a multi-stage launcher, you could have
each stage have the same sloping sides as the DC-C. Then each stage
would have the shape of a truncated cone, a frustum, and when stacked
one on top another the vehicle would have the shape of a single cone.
However, I prefer another method. It is known that you can increase
your payload using parallel staging with cross-feed fueling. Indeed
SpaceX intends to increase the payload of its Falcon Heavy launcher
using this method. Then another method for this reusable Falcon 9
would have each stage in the shape of a full cone, but the second
stage instead of being placed on top of the first stage would be
placed along side of it in parallel fashion.
In addition to increasing the payload this would have an another key
advantage. The high mass ratio of the Falcon 9 first stage, above 20
to 1, means that if it had high efficiency engines such as the NK-33
or RD-180 instead of the rather low efficiency Merlin 1C it would have
SSTO capability. However, because of the high investment of SpaceX in
the Merlin engines they no doubt are committed to its use.
But a key fact is that IF you have altitude compensation then even a
low efficiency, i.e., low chamber pressure, engine can achieve high
vacuum Isp while still providing good performance at sea level.
Methods of altitude compensation such as the aerospike have been
studied since the 60's. Then SpaceX could provide their DC-X styled
Falcon 9 stages with altitude compensation to give their stages SSTO
capability while still using the Merlin engines.
Then these SSTO stages could serve as low cost launchers for smaller
payloads, including being used for private, manned orbital vehicles.

The second model for the reusable Falcon 9 stages would be on the
ESA's proposed Intermediate eXperimental Vehicle (IXV):

Article:
Europe Aims to Launch Robotic Mini-Shuttle By 2020.
Rob Coppinger, SPACE.com ContributorDate: 13 June 2011 Time: 02:58 PM
ET
http://www.space.com/11948-robot-spa...hing-2020.html

This does not use the powered landing of the DC-X but rather uses a
glided landing via its lifting body shape. SpaceX does not like the
use of wings for landing because of the extra weight. But this design
would not have wings. It would have larger thermal protection weight
because the horizontal underside would have to be covered, whereas in
the DC-X mode only the base has to be covered. However, it would make
up for this in not requiring fuel for the powered landing.
In this case because the stages would have to maintain the aerodynamic
shape, they could not be stacked as for serial staging. Parallel
staging would have to be used. Once again this means the separate
stages could be used as SSTO's.


Bob Clark

On Oct 2, 1:48*am, Alan Erskine wrote:
On 2/10/2011 7:29 PM, Mike DiCenso wrote:

On Oct 1, 10:16 pm, Alan *wrote:
On 30/09/2011 7:09 AM, wrote:
You mean the Boeing idea for the shuttle (if I remember correctly, it
involved four boosters, two on each side of the ET)?

Actually, that system was two big LOX/Kerosene boosters that were
supposed to be powered by surplus F-1As
that had been intended for use on the Saturn V, but were never used
despite being built and certified.
-Mike

To answer your question, the foam was dislodged by vibration from the
SRB, not just aerodynamic forces.

Yes, but as Brian points out, it is not likely that F-1As would have
been gentle enough to prevent the foam from breaking off. Just look at
the ice that was dislodged by the Saturn V during launch, or on the
Energia booster, which also dislodged ice, which in turn damaged the
tiles on the Buran orbiter.
-Mike

On 3/10/2011 3:03 PM, Mike DiCenso wrote:
On Oct 2, 1:48 am, Alan wrote:
On 2/10/2011 7:29 PM, Mike DiCenso wrote:

On Oct 1, 10:16 pm, Alan wrote:
On 30/09/2011 7:09 AM, wrote:
You mean the Boeing idea for the shuttle (if I remember correctly, it
involved four boosters, two on each side of the ET)?

Actually, that system was two big LOX/Kerosene boosters that were
supposed to be powered by surplus F-1As
that had been intended for use on the Saturn V, but were never used
despite being built and certified.
-Mike

To answer your question, the foam was dislodged by vibration from the
SRB, not just aerodynamic forces.

Yes, but as Brian points out, it is not likely that F-1As would have
been gentle enough to prevent the foam from breaking off. Just look at
the ice that was dislodged by the Saturn V during launch, or on the
Energia booster, which also dislodged ice, which in turn damaged the
tiles on the Buran orbiter.
-Mike

Probably wouldn't have used foam anyway as the F-1s were LOX/RP1. Foam
is used on the LH2 tank to reduce boil-off. It's also used on the O2
tank but not as thick and this isn't the area where foam separated.

In article 92141f95-892b-4cec-a3eb-2b0043291358
@z19g2000vby.googlegroups.com, says...

Assuming they can get this to work, of course. It's an interesting
concept, to be sure. Good luck to Lord Musk-he's gonna need it. (and
no, he's not the Messiah when it comes to HSF-which a lot of folks,
especially those on spacepolitics.com, seem to think)

Certainly this is a fairly big "if". No one has attempted this before.

I'm glad Musk has the balls to try this. No other US aerospace company
seems to have the balls to do anything new on the scale that SpaceX
does.

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

On Oct 2, 7:17*pm, Robert Clark wrote:
*A couple of suggestions for the reusable version of the Falcon 9.
...

The second model for the reusable Falcon 9 stages would be on the
ESA's proposed Intermediate eXperimental Vehicle (IXV):

Article:
Europe Aims to Launch Robotic Mini-Shuttle By 2020.
Rob Coppinger, SPACE.com ContributorDate: 13 June 2011 Time: 02:58 PM
EThttp://www.space.com/11948-robot-spa...hing-2020.html



That Space.com link should be:

Europe Aims to Launch Robotic Mini-Shuttle By 2020.
http://www.space.com/11948-robot-spa...hing-2020.html

Bob Clark

In sci.space.policy message
, Sun, 2 Oct 2011 10:48:29, Brian Thorn
posted:

On Fri, 30 Sep 2011 10:00:03 -0400, Jeff Findley
wrote:

Falcon Heavy's LEO payload capacity is 117,000 lb (53 metric tons).
Even if making a Falcon Heavy reusable ate up 1/2 of the payload, it
would still be capable of putting more payload into orbit than the space
shuttle.

But they will probably run into problems making Falcon Heavy fully
reusable. If they're crossfeeding propellant from the strap-ons to the
core, the core will be too high/too fast/too far to turn around and
fly back to the Cape, but not high enough/fast enough/far enough to
reach a landing site in Europe or Africa. An ECAL-like landing in New
England or Newfoundland might be possible, but only for
high-inclination launches. The no man's land point will begin
somewhere around 4 minutes into flight, where Shuttle used to get the
"negative return" call.


There are islands in the Atlantic, although not many. Shuttle needed a
big wide runway; Falcon recovery would only need a pad. On a day when
the Atlantic is reasonably flat, Falcon could land on an aircraft
carrier. Anything that can land on a pad of the size in the video
(IIRC) should be able to land on a Nimitz.

Alternatively, though perhaps not when going to ISS, launch from the
Texas coast, recover in Louisiana Mississippi, or Florida; or Cuba,
Haiti, ..., Kourou, depending in inclination and range.

--
(c) John Stockton, nr London, UK. Turnpike v6.05 MIME.
Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
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