Liquid fueled alternatives to the Ares I solid rocket booster.

This Astronautix page gives the old Saturn F-1 engine a vacuum thrust
of 1,740,134 lbf at a weight of only 18,498 lb for a thrust to weight
ratio of nearly 100 to 1:

F-1.
http://www.astronautix.com/engines/f1.htm

The Astronautix page on the Ares I solids give it vacuum thrust of
3,480,122 lbf but an empty weight of 221,230 lb (!) for a thrust to
weight ratio of only 16 to 1 (!):

Ares.
http://www.astronautix.com/lvs/ares.htm

The tank mass for a kerosene-LOX engine is only about 1/100th that of
the propellant mass. So even if you used the same propellant mass as
the Ares I solids of about 1,400,000 lb that would only add 14,000 lb
to the lower stage empty mass. But actually the propellant mass would
probably be less since the F-1 had a better Isp at 304 s compared to
265 s for the Ares I solids.
Given this, how much larger payload could we launch to LEO using the 2
F-1 engines in place of the Ares I solids as the 1st stage?
How much could we launch to LEO using just 1 F-1 engine as the 1st
stage?


Bob Clark

On Aug 7, 4:25*am, Robert Clark wrote:
*This Astronautix page gives the old Saturn F-1 engine a vacuum thrust
of 1,740,134 lbf at a weight of only 18,498 lb for a thrust to weight
ratio of nearly 100 to 1:

F-1.http://www.astronautix.com/engines/f1.htm

*The Astronautix page on the Ares I solids give it vacuum thrust of
3,480,122 lbf but an empty weight of 221,230 lb (!) for a thrust to
weight ratio of only 16 to 1 (!):

Ares.http://www.astronautix.com/lvs/ares.htm

The tank mass for a kerosene-LOX engine is only about 1/100th that of
the propellant mass. So even if you used the same propellant mass as
the Ares I solids of about 1,400,000 lb that would only add 14,000 lb
to the lower stage empty mass. But actually the propellant mass would
probably be less since the F-1 had a better Isp at 304 s compared to
265 s for the Ares I solids.
Given this, how much larger payload could we launch to LEO using the 2
F-1 engines in place of the Ares I solids as the 1st stage?
*How much could we launch to LEO using just 1 F-1 engine as the 1st
stage?



The Russian RD-171 and RD-180 are high thrust, liquid-fueled engines
still in active operation. Here's the Astronautix pages on the RD-171
and RD-180:

RD-171
http://www.astronautix.com/engines/rd171.htm

RD-180
http://www.astronautix.com/engines/rd180.htm

You would need 2 to 3 of these to match the thrust of the Ares I
first stage solids. But the thrust to weight is so much better you
might be able to match the payload to orbit just using one of these
engines. (You would have 200,000 lbs less dry mass at launch.)


Bob Clark

On Aug 7, 4:28*am, Robert Clark wrote:

*The Russian RD-171 and RD-180 are high thrust, liquid-fueled engines
still in active operation. Here's the Astronautix pages on the RD-171
and RD-180:

RD-171http://www.astronautix.com/engines/rd171.htm

RD-180http://www.astronautix.com/engines/rd180.htm

*You would need 2 to 3 of these to match the thrust of the Ares I
first stage solids. But the thrust to weight is so much better you
might be able to match the payload to orbit just using one of these
engines. (You would have 200,000 lbs less dry mass at launch.)



This page gives altitude and velocity of the Ares I at first stage
separation as 59 km and 2024 m/s:

Space Launch Report - Ares I.
http://www.spacelaunchreport.com/ares1.html

Then we can estimate how much fuel it would take to reach this delta-
v, including the gravity drag for that altitude, based on the Isp of
the liquid fuel engines and the mass of the Ares upper stage.

A preliminary calculation shows the RD-180 wouldn't have enough
thrust for the fuel load required. However, the RD-171 should be able
to do it using the specifications given he

RD-171
http://www.astronautix.com/engines/rd171.htm

The second stage of the Ares I is about 175,000 kg, when you include
payload. The RD-171 weighs 9,500 kg. Even if you used as much fuel
mass as the SRB of 1,400,000 lb, a tankage mass ratio of 1/100th the
propellant mass for kerosene/LOX engines would only add 7,000 kg. So
call the the upper stage plus the empty weight of the lower stage
200,000 kg.
You want to reach the same velocity of 2,000 m/s and altitude of 50
km reached by the SRB. The delta-v required for the altitude can be
found from the equation v^2 = 2gh. So for h = 50,000 m, v = 990 m/s.
Air drag losses it turns out are relatively small for large
cylindrical rockets that get rapidly out of the atmosphere, about 150
m/s for medium sized launchers by this page:

Flight Mechanics of Manned Sub-Orbital Reusable Launch Vehicles with
Recommendations for Launch and Recovery.
http://www.spacefuture.com/archive/f... ecovery.shtml

So let's call the total delta-v 3,000 m/s. The Isp of the RD-171 is
given on the Astronautix page as 309 s at sea level and 337 s in
vacuum. Let's give it an average Isp of 320 s. Then the mass ratio is
exp(3,000/3200) = 2.554. So for a mass at first stage burnout of
200,000 kg, the mass at launch would be 2.554x200,000 = 510718 kg. Of
this 510,718-200,000 kg = 310,718 kg would be fuel, less than half of
the fuel load of the SRB for Ares I.
The launch mass of 510,718 kg = 1,123,580 lb is well within the
thrust capabilities of the RD-171 to lift, with its sea level thrust
of 1,697,300 lb.


Bob Clark

"Robert Clark" wrote in message
...
This Astronautix page gives the old Saturn F-1 engine a vacuum thrust
of 1,740,134 lbf at a weight of only 18,498 lb for a thrust to weight
ratio of nearly 100 to 1:

Lifting how much fuel?



F-1.
http://www.astronautix.com/engines/f1.htm

The Astronautix page on the Ares I solids give it vacuum thrust of
3,480,122 lbf but an empty weight of 221,230 lb (!) for a thrust to
weight ratio of only 16 to 1 (!):

Lifting how much fuel?

Have a look at the shuttle, it's got a big orange tank strapped to it with
two SRBs to lift the tank.

There had been some suggestions to use the Atlas V Heavy as an
alternative to the Ares I. According to this article NASA rejected the
Atlas V Heavy for human missions because of the payload requirements:

Lockheed and Bigelow Human-Rated EELV deal.
Man Rating the Atlas V
September 21st, 2006 by Chris Bergin
"NASA considered and rejected the use of Atlas V as a Space Shuttle
replacement for human space flight during their Exploration Systems
Architecture Study (ESAS) last year. The ESAS stated that it deemed
both Boeing Delta IV and Atlas V development options as ‘high risk’
for an on-time 2011 operational capability to meet CEV mass
requirements."
....
"The reason for the NASA ESAS man-rating concerns was due to the 25mT
CEV mass requirement, which ESAS maintained could not safely even be
met by the massive Atlas V Heavy variant. According to a Lockheed
Martin paper unveiled this week at the Space 2006 conference, the
basic Atlas V 401 can meet FAA and NASA man-rating requirements with
little modification with a much smaller capsule mass of 20,000 lbs."
http://www.nasaspaceflight.com/2006/...ted-eelv-deal/

The Atlas V 401 definitely could not make the 25 mT payload
requirements to match the Ares I performance. This is an already
existing booster so was suggested as an alternative to the Ares I to
save cost. The Atlas V HLV is only a proposed booster and has not been
built or authorized. But its suggested payload to orbit would exceed
that of the Ares I.
It uses 3 RD-180's in its lower stage with a thrust of about
3,000,000 lb which is about comparable to the Ares I solids, but with
a lower dry mass so should indeed be able to exceed the Ares I in
payload to orbit. NASA's claim that it could not "safely" reach the 25
mT payload goal is puzzling, unless it means "man rating" of the
engines but that should be true regardless of the payload mass.

All Atlas V versions use a smaller engine, sometimes in pairs, for
the upper stage, the RL-10A:

RL-10.
http://www.astronautix.com/engines/rl10.htm

The J-2X engine planned for the Ares I upper stage has 10 times the
thrust of one RL-10A:

J-2.
http://www.astronautix.com/engines/j2.htm

Using two RD-180's, cheaper than the three proposed for the Atlas V
HLV, to replace the Ares I first stage, while also keeping the J-2X
for the upper stage, would actually allow you to increase the payload
to orbit.

The same would be true of the RS-84 engine if development were
restarted. This engine was also planned to be reusable:

July 21st, 2003
Kerosene Engine Passes Design Milestone.
Written by Fraser Cain.
http://www.universetoday.com/2003/07...ign-milestone/

This article from 2003 stated a full scale model would have been
ready for testing four years after that in 2007. The program was
cancelled in 2004 however. If you suppose there was an additional year
of development before it was cancelled in 2004, then conceivably a
full scale model could be ready for testing by 2012 if development
were restarted this year.


Bob Clark

On Aug 7, 4:45*am, Robert Clark wrote:
*There had been some suggestions to use the Atlas V Heavy as an
alternative to the Ares I. According to this article NASA rejected the
Atlas V Heavy for human missions because of the payload requirements:

Lockheed and Bigelow Human-Rated EELV deal.
Man Rating the Atlas V
September 21st, 2006 by Chris Bergin
"NASA considered and rejected the use of Atlas V as a Space Shuttle
replacement for human space flight during their Exploration Systems
Architecture Study (ESAS) last year. The ESAS stated that it deemed
both Boeing Delta IV and Atlas V development options as ‘high risk’
for an on-time 2011 operational capability to meet CEV mass
requirements."
...
"The reason for the NASA ESAS man-rating concerns was due to the 25mT
CEV mass requirement, which ESAS maintained could not safely even be
met by the massive Atlas V Heavy variant. According to a Lockheed
Martin paper unveiled this week at the Space 2006 conference, the
basic Atlas V 401 can meet FAA and NASA man-rating requirements with
little modification with a much smaller capsule mass of 20,000 lbs."http://www.nasaspaceflight.com/2006/09/lockheed-and-bigelow-human-rat...

* The Atlas V 401 definitely could not make the 25 mT payload
requirements to match the Ares I performance. This is an already
existing booster so was suggested as an alternative to the Ares I to
save cost. The Atlas V HLV is only a proposed booster and has not been
built or authorized. But its suggested payload to orbit would exceed
that of the Ares I.
*It uses 3 RD-180's in its lower stage with a thrust of about
3,000,000 lb which is about comparable to the Ares I solids, but with
a lower dry mass so should indeed be able to exceed the Ares I in
payload to orbit. NASA's claim that it could not "safely" reach the 25
mT payload goal is puzzling, unless it means "man rating" of the
engines but that should be true regardless of the payload mass.

*All Atlas V versions use a smaller engine, sometimes in pairs, for
the upper stage, the RL-10A:

RL-10.http://www.astronautix.com/engines/rl10.htm

*The J-2X engine planned for the Ares I upper stage has 10 times the
thrust of one RL-10A:

J-2.http://www.astronautix.com/engines/j2.htm

*Using two RD-180's, cheaper than the three proposed for the Atlas V
HLV, to replace the Ares I first stage, while also keeping the J-2X
for the upper stage, would actually allow you to increase the payload
to orbit.

*The same would be true of the RS-84 engine if development were
restarted. This engine was also planned to be reusable:

July 21st, 2003
Kerosene Engine Passes Design Milestone.
Written by Fraser Cain.http://www.universetoday.com/2003/07...-passes-design...

*This article from 2003 stated a full scale model would have been
ready for testing four years after that in 2007. The program was
cancelled in 2004 however. If you suppose there was an additional year
of development before it was cancelled in 2004, then conceivably a
full scale model could be ready for testing by 2012 if development
were restarted this year.


So there are several options if the Ares I solids are to be replaced
with liquid fueled engines for manned missions. All of these could
surpass the Ares I in payload to orbit:

1.)Replace the solids with a single RD-171. This engine has been used
many times, but is a Russian engine. It would be cheaper. But I
consider it unlikely that the U.S. would want to be dependent on a
Russian engine for all manned flights for a long period.

2.)Replace the solids with two RD-180's and keep the J-2X engine now
proposed for the Ares I upper stage. The RD-180 has been contracted at
least to be made by an American manufacturer, Pratt & Whitney, but I'm
informed none have actually been made in the U.S.
This would be more palatable to be used for all near term manned
missions if the ones used are made in the U.S. The fact there are two
needed would increase the cost as well as the fact they would be made
by an American company.

3.)Use the Atlas V HLV with 3 RD-180's for the lower stage, with the
RL-10A, perhaps two of them, for the upper stage. Using 3 RD-180's
would be more expensive but you might save on the cheaper RL-10A's for
the upper stage compared to the J-2X.

4.)Restart development of the RS-84. Two of these would give
comparable performance to using 2 RD-180's with a J-2X powered upper
stage. This would be reusable so it gives you some more options for
saving money if a flyback booster capability is developed. Main
disadvantage is that it's still not completed. You would then have to
figure also development costs.

Cheapest option is undoubtedly #1. But I consider it politically
impossible.
My personal preferred option is #4 because it would be an American
engine and also because it would be reusable, though very likely more
expensive than the others.


Bob Clark

On Aug 7, 5:01*am, Robert Clark wrote:
On Aug 7, 4:45*am, Robert Clark wrote:





*There had been some suggestions to use the Atlas V Heavy as an
alternative to the Ares I. According to this article NASA rejected the
Atlas V Heavy for human missions because of the payload requirements:

Lockheed and Bigelow Human-Rated EELV deal.
Man Rating the Atlas V
September 21st, 2006 by Chris Bergin
"NASA considered and rejected the use of Atlas V as a Space Shuttle
replacement for human space flight during their Exploration Systems
Architecture Study (ESAS) last year. The ESAS stated that it deemed
both Boeing Delta IV and Atlas V development options as ‘high risk’
for an on-time 2011 operational capability to meet CEV mass
requirements."
...
"The reason for the NASA ESAS man-rating concerns was due to the 25mT
CEV mass requirement, which ESAS maintained could not safely even be
met by the massive Atlas V Heavy variant. According to a Lockheed
Martin paper unveiled this week at the Space 2006 conference, the
basic Atlas V 401 can meet FAA and NASA man-rating requirements with
little modification with a much smaller capsule mass of 20,000 lbs."http://www.nasaspaceflight.com/2006/09/lockheed-and-bigelow-human-rat...

* The Atlas V 401 definitely could not make the 25 mT payload
requirements to match the Ares I performance. This is an already
existing booster so was suggested as an alternative to the Ares I to
save cost. The Atlas V HLV is only a proposed booster and has not been
built or authorized. But its suggested payload to orbit would exceed
that of the Ares I.
*It uses 3 RD-180's in its lower stage with a thrust of about
3,000,000 lb which is about comparable to the Ares I solids, but with
a lower dry mass so should indeed be able to exceed the Ares I in
payload to orbit. NASA's claim that it could not "safely" reach the 25
mT payload goal is puzzling, unless it means "man rating" of the
engines but that should be true regardless of the payload mass.

*All Atlas V versions use a smaller engine, sometimes in pairs, for
the upper stage, the RL-10A:

RL-10.http://www.astronautix.com/engines/rl10.htm

*The J-2X engine planned for the Ares I upper stage has 10 times the
thrust of one RL-10A:

J-2.http://www.astronautix.com/engines/j2.htm

*Using two RD-180's, cheaper than the three proposed for the Atlas V
HLV, to replace the Ares I first stage, while also keeping the J-2X
for the upper stage, would actually allow you to increase the payload
to orbit.

*The same would be true of the RS-84 engine if development were
restarted. This engine was also planned to be reusable:

July 21st, 2003
Kerosene Engine Passes Design Milestone.
Written by Fraser Cain.http://www.universetoday.com/2003/07...-passes-design...

*This article from 2003 stated a full scale model would have been
ready for testing four years after that in 2007. The program was
cancelled in 2004 however. If you suppose there was an additional year
of development before it was cancelled in 2004, then conceivably a
full scale model could be ready for testing by 2012 if development
were restarted this year.

*So there are several options if the Ares I solids are to be replaced
with liquid fueled engines for manned missions. All of these could
surpass the Ares I in payload to orbit:

1.)Replace the solids with a single RD-171. This engine has been used
many times, but is a Russian engine. It would be cheaper. But I
consider it unlikely that the U.S. would want to be dependent on a
Russian engine for all manned flights for a long period.

2.)Replace the solids with two RD-180's and keep the J-2X engine now
proposed for the Ares I upper stage. The RD-180 has been contracted at
least to be made by an American manufacturer, Pratt & Whitney, but I'm
informed none have actually been made in the U.S.
This would be more palatable to be used for all near term manned
missions if the ones used are made in the U.S. The fact there are two
needed would increase the cost as well as the fact they would be made
by an American company.

3.)Use the Atlas V HLV with 3 RD-180's for the lower stage, with the
RL-10A, perhaps two of them, for the upper stage. Using 3 RD-180's
would be more expensive but you might save on the cheaper RL-10A's for
the upper stage compared to the J-2X.

4.)Restart development of the RS-84. Two of these would give
comparable performance to using 2 RD-180's with a J-2X powered upper
stage. This would be reusable so it gives you some more options for
saving money if a flyback booster capability is developed. Main
disadvantage is that it's still not completed. You would then have to
figure also development costs.

*Cheapest option is undoubtedly #1. But I consider it politically
impossible.
*My personal preferred option is #4 because it would be an American
engine and also because it would be reusable, though very likely more
expensive than the others.

* * *Bob Clark- Hide quoted text -

- Show quoted text -

since all this the number of astronauts has been cut from what 8 to 5?
something like that........

nasa intentially speced too many astronauts so existing expendables
couldnt be used

Androcles wrote:

Have a look at the shuttle, it's got a big orange tank strapped to it with
two SRBs to lift the tank.

That's because it doesn't have any engines attached to it :

http://www.spacefuture.com/archive/a...periment.shtml

Unfortunately, the tank has a bunch of crappy poly foam sprayed onto it.

Robert Clark wrote in news:45055e8f-c41e-4c7a-8af7-
:

This Astronautix page gives the old Saturn F-1 engine a vacuum thrust
of 1,740,134 lbf at a weight of only 18,498 lb

This weight is only that of the engine itself. It does not include
the fuel, tanks, and other support structures.


The Astronautix page on the Ares I solids give it vacuum thrust of
3,480,122 lbf but an empty weight of 221,230 lb

This weight includes the fuel tank where all the solid fuel
was stored.

You're comparing apples to oranges. Two different technologies.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

On Aug 7, 1:25*am, Robert Clark wrote:
*This Astronautix page gives the old Saturn F-1 engine a vacuum thrust
of 1,740,134 lbf at a weight of only 18,498 lb for a thrust to weight
ratio of nearly 100 to 1:

F-1.http://www.astronautix.com/engines/f1.htm

*The Astronautix page on the Ares I solids give it vacuum thrust of
3,480,122 lbf but an empty weight of 221,230 lb (!) for a thrust to
weight ratio of only 16 to 1 (!):

Ares.http://www.astronautix.com/lvs/ares.htm

The tank mass for a kerosene-LOX engine is only about 1/100th that of
the propellant mass. So even if you used the same propellant mass as
the Ares I solids of about 1,400,000 lb that would only add 14,000 lb
to the lower stage empty mass. But actually the propellant mass would
probably be less since the F-1 had a better Isp at 304 s compared to
265 s for the Ares I solids.
Given this, how much larger payload could we launch to LEO using the 2
F-1 engines in place of the Ares I solids as the 1st stage?
*How much could we launch to LEO using just 1 F-1 engine as the 1st
stage?

* *Bob Clark

You are very correct, in that liquid fueled stages are superior in
just about every application of getting payloads into LEO and beyond.
However, they can require more technical expertise than solid fuel
alternatives.

The Saturn 5 was nearly 100% foolproof, and at least thus far our most
failsafe alternative, that's also 1000+% bought and paid for. Problem
is that all the essential R&D is oddly missing in action (along with
those 700 large boxes of clearly marked Apollo mission and original
science stuff), and there's not an original Zionist Nazi rocket
scientist in sight, perhaps because they all flew the coop as soon as
their ARPA and NASA job was done, perhaps because they were actually
some of the worse Nazi bad guys, and more than likely Zionist to boot.

For today's expertise in liquid fly-by-rocket standards, the Saturn 5
package was somewhat inert hefty. Without all that much trouble, I
believe 10% of its inert mass could be trimmed and thus replaced with
even greater payload. Now we get to wait until Russia, China or India
manage to do one that's equal or better, or perhaps even ESA.

Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”