I have a very difficult time understanding how one computes orbits,
trajectories, launch windows, delta-v, etc. Can any of you answer
these two questions:
from the Earth to LEO and launching from the Earth to L1? (I found
the answer to this question: One Way - Delta-v = 3.77 km/s (1.87
propellant mass surchage); Round Trip - Delta-v = 3.77 km/s (up)
+ .77 km/s (down) = 4.54 km/s total (2.69 total mass surchage)
(Source: "Strategic Considerations for Cislunar Space
Infrastructure", by Wendell W. Mendell (available online - just
google if you're interested in reading yourself)
Do you know where there are currently any launch vehicles capable of
transporting payloads to L1?
Jack
--- In ssi_list@... "jdr7181 "
> I have a very difficult time understanding how one computes
orbits,
> trajectories, launch windows, delta-v, etc. Can any of you answer
> these two questions:
>
> Is there a signficant difference in launch costs between launching
> from the Earth to LEO and launching from the Earth to L1? (I found
> the answer to this question: One Way - Delta-v = 3.77 km/s (1.87
> propellant mass surchage); Round Trip - Delta-v = 3.77 km/s (up)
> + .77 km/s (down) = 4.54 km/s total (2.69 total mass surchage)
> (Source: "Strategic Considerations for Cislunar Space
> Infrastructure", by Wendell W. Mendell (available online - just
> google if you're interested in reading yourself)
>
> Do you know where there are currently any launch vehicles capable
of
> transporting payloads to L1?
>
> Jack
The issue that confronts you is that of the fuel to payload mass
ratio. If you make your payload small enough it can get to L1. Keep
in mind all of the probes we've sent beyond L1.
TangoMan
--- "jdr7181 jdr7181@... jdr7181@...
>
> Is there a signficant difference in launch costs
> between launching
> from the Earth to LEO and launching from the Earth
> to L1? (I found
Delta-V from surface of Earth to LEO at 300 km
altitude is about 7,800 metres per second.
Delta-V from surface of Earth to LTO (Lunar Transfer
Orbit - which gets you to L-1 or the Moon) is about
10,500 metres per second.
Upon arrival at L-1 (a few days aftger launch) a
modest braking burn is required which I have
neglected.
> the answer to this question: One Way - Delta-v =
> 3.77 km/s (1.87
> propellant mass surchage); Round Trip - Delta-v =
> 3.77 km/s (up)
> + .77 km/s (down) = 4.54 km/s total (2.69 total mass
> surchage)
I do not understand these numbers.
They are way too low. Maybe they represent the
braking burn component, to circularize the elliptical
LTO orbit at L1.
What does "round trip" mean in this context ?
>
> Do you know where there are currently any launch
> vehicles capable of
> transporting payloads to L1?
>
Yes, most launch vehicles can get you to LTO quite
easily, some need an extra upper stage. Ariane could
do it quite nicely, also most of the Russian/Ukrainian
vehicles.
Consider this, the energy to achieve LTO from Earth's
surface only slightly more than the energy of a
Geosynchronous transfer orbit.
After separating from the launch vehicle you will
coast for a few days, then at apogee you will need an
onboard propulsion system to circularize the orbit.
Charles R.
>
> --- "jdr7181 "
> >
> > Is there a signficant difference in launch costs
> > between launching
> > from the Earth to LEO and launching from the Earth
> > to L1? (I found
>
> Yes.
>
> Delta-V from surface of Earth to LEO at 300 km
> altitude is about 7,800 metres per second.
>
> Delta-V from surface of Earth to LTO (Lunar Transfer
> Orbit - which gets you to L-1 or the Moon) is about
> 10,500 metres per second.
>
> Upon arrival at L-1 (a few days aftger launch) a
> modest braking burn is required which I have
> neglected.
>
> > the answer to this question: One Way - Delta-v =
> > 3.77 km/s (1.87
> > propellant mass surchage); Round Trip - Delta-v =
> > 3.77 km/s (up)
> > + .77 km/s (down) = 4.54 km/s total (2.69 total mass
> > surchage)
>
> I do not understand these numbers.
> They are way too low. Maybe they represent the
> braking burn component, to circularize the elliptical
> LTO orbit at L1.
(maybe I misunderstood the context):
http://ares.jsc.nasa.gov/HumanExplore/Exploration/EXLibrary/DOCS/EIC04
2.HTML
Tables 1 and 2.
> What does "round trip" mean in this context ?
From Earth's surface to L1 and back again.
> > Do you know where there are currently any launch
> > vehicles capable of
> > transporting payloads to L1?
> >
> Yes, most launch vehicles can get you to LTO quite
> easily, some need an extra upper stage. Ariane could
> do it quite nicely, also most of the Russian/Ukrainian
> vehicles.
>
> Consider this, the energy to achieve LTO from Earth's
> surface only slightly more than the energy of a
> Geosynchronous transfer orbit.
>
> After separating from the launch vehicle you will
> coast for a few days, then at apogee you will need an
> onboard propulsion system to circularize the orbit.
Can you estimate the difference in cost between launching a satellite
to LEO and launching one to L1? Just pick a size and define the
variable as best you can, if possible.
Jack
--- In ssi_list@... "jdr7181 "
satellite
> to LEO and launching one to L1? Just pick a size and define the
> variable as best you can, if possible.
>
> Jack
Consider Delta IV rocket, with a cost of $170 million. It has a GLOW
of 733,400 kg, can deliver to a 185 km orbit a payload of 24,800 kg,
and to GEO a payload of 10,843 kg.
Arianne 5, with a cost of $180 million, and a GLOW of 746,000 kg,
delivers 16,000 kg to a 407 km orbit and 6,800 kg to GEO.
A Zenit 3SL, costing $90 million, and a GLOW of 471,000 kg, lifts
5,250 kg to GEO.
Maybe the Chinese Long March rockets have good price/performance. I
don't think the Dnepr has the oomph (that's a technical term :) to
loft to GEO or L1, but that's just my WAG.
Insert your own assumptions keeping in mind that the article you
cited was referencing a situation with a payload launched from LEO
at 300 km, using a seperate rocket with LOX/LH2, tankage factors and
aerobraking calculations. The figures I quote above take the payload
directly to GEO which is more energy intensive than L1.
Good luck,
TangoMan
--- "jdr7181 jdr7181@... jdr7181@... >
> Can you estimate the difference in cost between
> launching a satellite
> to LEO and launching one to L1? Just pick a size and
> define the
> variable as best you can, if possible.
>
> Jack
Look at the specs for the various launch vehicles,
they all quote for LEO and GTO.
L1 is only slightly higher than GTO.
That will give you a good first approximation.
It varies somewhat for the different launch vehicles.
Cheers,
Charles R.
Do you mean GEO, or really GTO ?
--- "victoriatangoman victoriatangoman@...
> --- In ssi_list@... "jdr7181
> "
>
> > Can you estimate the difference in cost between
> launching a
> satellite
> > to LEO and launching one to L1? Just pick a size
> and define the
> > variable as best you can, if possible.
> >
> > Jack
>
> Consider Delta IV rocket, with a cost of $170
> million. It has a GLOW
> of 733,400 kg, can deliver to a 185 km orbit a
> payload of 24,800 kg,
> and to GEO a payload of 10,843 kg.
>
> Arianne 5, with a cost of $180 million, and a GLOW
> of 746,000 kg,
> delivers 16,000 kg to a 407 km orbit and 6,800 kg to
> GEO.
>
Ariane delivers to GTO, not GEO. So do most other
vehicles. Proton is different, they deliver to GEO.
Usually the satellite does he final GTO to GEO kick
itself using on board motor.
Please clarify.
Charles R.
--- "jdr7181 " wrote: Is there a signficant difference in launch costs between launching from the Earth to LEO and launching from the Earth to L1? (I found Yes. Delta-V from surface of Earth to LEO at 300 km altitude is about 7,800 metres per second. No. It's more like 9,300-10000 meters per second. There's losses in the atmosphere and some losses called 'gravity losses' where you've carried the fuel up with you before burning it, it wastes delta-v/fuel to do that. 7,800 meters per second would be right if there was no atmosphere and the burn was instantaneous at ground level, but the rocket comes apart if you try that, or the astronauts do ;-)
Delta-V from surface of Earth to LTO (Lunar Transfer Orbit - which gets you to L-1 or the Moon) is about 10,500 metres per second. No these are too low too, by about the same delta-v.
Charles R.
JSC has a very comprehensive listing of launch vehicle
costs broken down by each rocket.
There are also various cost models that you can play
with. The biggest bang for the buck is the ariane 5,
which can deliver 6800 kg into GTO. Though its
reliability as of lately has been horrid. In fact,
reliability is one thing you really need to put into
perspective but its very hard to quantify.
As for the long march, regardless of its pricing,
due to TTAs (technology transfer agreement) that are
controlled by the state department it is impossible to
launch anything with a US component on it from china.
I don't see this changing anytime in the near future.
Now, if you don't care about time so much, you can
lift to LEO and the use some SPT thrusters to orbit
raise your spacecraft to a LTO. While this can be
time consuming it is also very cheap. About a year
ago,a european satellite was placed in the wrong orbit
by an arianne 5 and had to do this in order to reach
GEO.
-Ryan Z
Huh?
Shtil doesn't have a kick motor, but if you loaded a small one on board, it can launch to GEO for about $1500/kg,
although only 150 kgs payload.
Incidentally Proton is cheaper than Ariane on that chart.
The proton is cheap. I was thinking more along the
lines of putting mass into orbit. With the ability to
put upwards towards 6800 kg into space, in the long
run putting infrastructure up would be cheaper using
an arianne because less overall launches would be
needed.
rockets like that. However the biggest problem is
payload. At this point I do not remember how much
mass the original poster wanted to shoot up, but if we
are talking infrastructure, I would go for rockets
that can deliver the most payload per launch, which
means the heavy lifters like new atlas and delta, h2a
and arianne 5. The proton though is still the best
and most dependable rocket for medium sized payloads
(5k kg and less).
Ryan Z.
The proton is cheap. I was thinking more along the lines of putting mass into orbit. With the ability to put upwards towards 6800 kg into space, in the long run putting infrastructure up would be cheaper using an arianne because less overall launches would be needed. The data doesn't seem to agree with you; the per-launch cost is about half that of Ariane and the payload is almost the same.
The shtil is very cheap, as are alot of other little rockets like that. I'm not aware of any other vehicle, anywhere near that cheap; by a factor of 5. Even if you only used it to launch fuel to LEO it could have a dramatic effect on overall costs of a large endeavour, Sure, you'd have to launch thousands of times; but so what? That would make it even cheaper, due to volume discounts.
However the biggest problem is payload. At this point I do not remember how much mass the original poster wanted to shoot up, but if we are talking infrastructure, I would go for rockets that can deliver the most payload per launch, which means the heavy lifters like new atlas and delta, h2a and arianne 5. You must be made of money! Can I borrow some? ;-)
The proton though is still the best and most dependable rocket for medium sized payloads (5k kg and less). Yes, if you have to launch in one lump, like a geosat does. Do you in fact?
I've just uploaded a LEO to L1 delta-v vs flight time graph in the
files section.
20L1%20Graph.pdf
TangoMan
Where did you get the graph?
"victoriatangoman "
I've just uploaded a LEO to L1 delta-v vs flight time graph in the
files section.
I thought it might be relevent to the discussion.
20L1%20Graph.pdf
TangoMan
> Where did you get the graph?
>
> Ron
> ******
over the years and some of it I have no sources for. Sorry.
TangoMan