It is slowly registering that
Space X is going to succeed in launching large payloads for under $1000 per pound
and this is helping fuel the already present space rush that is obviously been
fueled by every respectable nation state and plenty of corporate adventurers
also.
We can quickly expect a number of
new commercial space stations been created to take advantage of this pricing
capability and tonnage deliverability.
Fifty tons is a lot of supplies and multiple launches allow a rapid
build up.
An orbital space wheel is
suddenly no longer that far away and could provide the destination space
tourism actually needs. Recall 2001, if
you wish to see how it may look.
Obviously the military and governments
are still the big customers but it is now turning into real rush as capacity
keeps been boosted almost exponentially.
The SpaceX Falcon Heavy Booster: Why Is It Important?
by John K. Strickland, Jr.
The announcement of the Falcon Heavy in early April, 2011 was a
potential game-changer in the space launch industry. The Falcon Heavy is slated
to launch twice the payload of the Shuttle at about one-fifteenth the cost of a
Shuttle launch — an approximate 97% reduction in launch costs compared with the
Shuttle!
“How can Musk do that?”
Many months after the Falcon Heavy announcement there is still
confusion about its significance, and in some quarters outright disbelief
remains regarding the launch prices actually posted on the SpaceX website for
the Falcon Heavy. No other company has posted fixed launch prices on the
Internet — only SpaceX. The actual taxpayer cost of US government launches can
only be guessed by calculating from the cost-plus contract costs, which are
usually for multiple launches from the same customer. If SpaceX does multiple
launches, the posted price would be reduced depending on the number of
launches. Almost any commodity’s price decreases if production rates increase.
Rockets are no different.
What amazes people is that SpaceX has broken the long-sought 1,000
dollars a pound to orbit price barrier with a rocket which is still expendable.
“How can he (SpaceX CEO Elon Musk) possibly do this?” they ask. The Chinese
have said flatly that there is no way they can compete with such a low price.
It is important to remember that this was not done in a single step. The Falcon
9 already has a large price advantage over other boosters, even though it does
not have the payload capacity of some of the largest ones.
The “Heavy” will even this score and then some. At last count, SpaceX
had a launch manifest of over 40 payloads, far exceeding any current government
contracts, with more being added every month. These are divided between the
Falcon 9 and the Falcon Heavy.
The Falcon Heavy is similar in conformation to the Delta 4 Heavy, which
is the only rocket currently in service that is fair to compare to the Falcon
Heavy. The “Heavy” will consist of three Falcon 9 stages strapped together (two
side stages and a core stage which has a small upper stage and payload with
fairing). The Falcon stages are stretched and the nine Merlin engines on each
will be upgraded to have more thrust than the current engines. With a total
liftoff mass of 1400 metric tons, it will put 53 metric tons into a standard
200 km Earth orbit at 28 degrees. (The 200 km orbit is a standard orbit to
start from, for example, for injection into a geosynchronous transfer orbit —
payloads are not left in this 200 km orbit.) Each of the “Heavy’s” three stages
are about 12 feet in diameter, so based on data from the Ares I, the payload
fairing could be up to 18 feet in diameter. The currently proposed shroud
diameter is 17 feet. The total thrust at liftoff will be 3.8 million pounds or
about 1700 tons, or 50% of the Saturn V’s thrust. This will make it the world’s
largest and most powerful operational rocket once it has flown. The first
flight is anticipated in 2013 from Vandenburg Air Force Base in California
A 10-fold reduction in cost per pound to orbit
To fairly compare the two rocket performances, you really have to look
at the numbers. Although the Falcon Heavy looks similar to a Delta 4 Heavy, its performance is
much higher and, simultaneously, its cost per launch is much lower.
It can put 53 metric tons (117,000 lbs) in orbit compared to the Delta 4
Heavy’s 23 metric tons (or 50,600 lbs), a 230% improvement. At the same time,
it only costs about $100 million per launch, while the Delta 4 Heavy launches
cost $435 million each (calculated from an Air Force contract of $1.74 billion
for 4 launches).
Comparing the payload costs to orbit is useful here. The Delta 4 Heavy
can put up 23 metric tons at about $19 million/ton or $8600 per pound). If it
could put up 53 metric tons at the same price per ton, then that payload launch
would cost almost exactly 1 billion dollars. Since the Falcon Heavy’s posted
price per launch centers on 100 million dollars (and the corresponding payload
price is about $850 per pound or $1.9 million per ton), it is easy to see that
the future (< 2 years) price of a commercial Falcon Heavy launch per unit
weight is almost exactly one-tenth of the current Delta 4 Heavy price.
These results show that using the average posted price value of $100
million, the Falcon Heavy actually can be launched for about one-fourth the
cost of a Delta IV Heavy (4.35 times cheaper per launch), yet it carries
2.31 times as much payload! This means the current cost per pound to LEO for
the Delta IV Heavy is 4.35 times 2.31 = 10.05 or almost exactly 10 times more
expensive (by multiplying the two ratios together).
How SpaceX does it
When people see this cost comparison, they ask all over again “How can
he (Musk) do that?” How can the Falcon outperform the Delta by such a wide
margin? The three main reasons seem to be (1) low manufacturing cost (2) low
operational cost (time efficient operations design and low man-hours needed per
launch) and (3) high efficiency performance in flight. The first two have
already been demonstrated by the Falcon 9, and they continue to be
improved, such as a recently announced two-thirds reduction of fuel loading
time. The SpaceX paradigm is one of continuous improvement.
The first reason (low manufacturing cost) is exercised again in the
“Heavy” by using three nearly identical rocket stages (instead of two solids
and a core stage), which means more production of the same units, thus reducing
their unit cost. The SpaceX plant in Hawthorne ,
California
Within five years, SpaceX expects to be producing more large rocket
engines per year (several hundred) than all other rocket companies on the
planet combined. Engine production costs will thus decline still more. (Dragon
production, depending on demand, is planned for a rate of one every six to
eight weeks.)
The third reason (high efficiency in flight) is partly achieved by
the standard methods of making the engines fuel efficient, with high thrust and
low mass, and making the overall structural mass of each stage as low as
possible. Musk has apparently done this better than anyone else. For
example, the two side boosters have a fully fueled to empty mass ratio of 30.
Additional flight efficiency is achieved by propellant cross-feeding (see
below).
The Falcon rockets also use a short upper stage which consists of a
single Merlin engine to place the payload into orbit. Musk has been talking
about creating a hydrogen-oxygen upper stage, which could boost the total
Falcon Heavy payload close to the minimum for a “true” heavy lift vehicle, or
about 70 tons. This engine could enter service before 2015.
Propellant cross-feeding
Part of the Falcon Heavy flight efficiency is achieved by a method that
has been known for decades, but no one else has been willing to attempt to
implement it. This method is called propellant cross-feeding. All three Falcon
boosters use full thrust at takeoff to lift the massive rocket. During
flight, the outer two stages pump part of their propellant into the center
stage. They thus run out of propellant faster than you would expect, but the
result is that the center (core) stage has almost a full load of propellant at
separation where it is already at altitude and at speed. Unfortunately,
very little information has been released on the cross-feeding system to be
used by the Falcon Heavy. It would only be used for payloads exceeding 50
metric tons.
The cross-feeding scheme used by Space X apparently does not pump fuel
into the tanks of the core stage. Instead, the three core-stage engines next to
each side booster are fed directly from the side booster’s tanks. This is very
similar to how the shuttle’s external tank feeds the shuttle main engines
(SMEs). In the case of the Falcon Heavy, of course, the two side booster’s
tanks are feeding propellant to 12 engines instead of 9, so they run out of
propellant faster. At some point after liftoff, of course, you do not need the
full thrust of all 27 engines to maintain acceleration, as much of the mass
(propellant) has already been used. The core stage engines will then apparently
be throttled down while the side stages continue to burn at full thrust.
Presumably, only the center three engines in the core stage are using propellant
from the core stages tanks. Thus, when the side stages separate, most of the
core stage’s propellant is still there, and then all the core stage engines can
burn at full thrust. Assuming that the core stage is going several thousand
miles an hour at separation and is perhaps 30 miles high or more, it is as if
an entire stretched Falcon 9 rocket starts its liftoff at separation.
Separation of fuel lines like this occurred every time the external tank
separated from the space shuttle and when the old original Atlas shed its two
side booster engines.
What can we do with it?
The Falcon Heavy, when it enters service, creates a new payload weight
class. This capability can be exploited in multiple ways for existing payloads,
such as launching more than one communications satellite in a single payload.
The large payload fairing gives payload designers a lot of room for their
payloads, which do not need to be as compact, and can thus be wider and more
than twice as heavy as a shuttle payload.
The Falcon Heavy also opens up a window to much larger, heavier
payloads. Much concern was expressed after the last shuttle launch about the
loss of the shuttle’s lift capacity. The Falcon Heavy will be able to place
more than two shuttle payloads in orbit in one launch at about 1/15 of the
price of a single shuttle launch. The only thing missing is the ability to move
items placed in orbit to a specific place where you want them, such as the
space station. The Dragon capsule (and the other smaller delivery vehicles) will
cover that for smaller supplies. For larger items such as new habitats or
instruments, just two large payloads, a Low Earth Orbit space tug and a propellant depot,
would solve the problem. This would allow much larger space station modules to
be launched and thus allow new additions to the station. The Large Centrifuge
Facility is the most critical item that was deleted during the multi-decades of
budget-cutting that affected the station. It is still a vitally needed module
to allow studies of mammals in low gravity fields to prove that we can colonize
Mars. Also, additional crew habitat and laboratory modules were originally
planned and then cancelled.
The only shuttle capability that the Falcon Heavy (and its payloads)
would not provide is the ability to return large objects from orbit, but this
has been rarely required. Considering that the cost of shuttle launches has
recently been pegged at $1.5 billion apiece, (about $75 million per ton of
payload), in most cases it would be far cheaper to build a new payload than to
bring it back in a shuttle.
There are many other large payloads that a Falcon Heavy could launch
that do not involve the space station. With a 53 to 70 ton payload, a very large
optical space telescope could be orbited to replace Hubble. Discussions are
also underway for a potentially low-price-shattering Mars mission which would
use a Dragon capsule to land deep drilling and other robotic equipment. The
mission would presumably use a higher energy (hydrogen/oxygen) engine along
with an enlarged upper stage to boost the Dragon to escape velocity toward Mars
with the robotic drilling equipment inside. Since the Dragon plus its payload
would be over 10 times heavier than any previously landed payload, it would
have to use newer methods of decelerating in the atmosphere before landing on
Mars. A modified Dragon capsule could also potentially be the basis of a much
cheaper Mars sample return mission.
Fifty tons to orbit has been an assumed minimum unit mass for practical
construction of space solar power. Even with the Falcon Heavy to launch the
equipment, space solar cannot yet compete with coal or nuclear power, but even
now, it could compete with ground solar or wind power, especially if intended
for base load supply. Five Falcon Heavy launches could place 250 tons of solar
panels in Earth orbit. An additional launch could orbit a solar powered ion or
plasma tug, which could move the equipment to Geosynchronous Earth Orbit,
avoiding the huge penalty of using liquid fuel to reach the higher orbit.
Alternately, a single “Heavy” launch could place a single prototype 50-ton
powersat in orbit to be used as an emergency power supply. This could be enough
to supply about 10 megawatts to disaster sites over an entire continent via
laser beam.
For human missions beyond LEO, the Falcon Heavy could launch a long
duration Dragon capsule (about 10 metric tons) attached to a 42 ton crew
habitat, or an Orion (21 metric tons) attached to a 32 ton habitat (these
numbers do not include propellant to reach escape trajectory, which could be
obtained from a propellant depot). Either configuration would be suitable for an
asteroid mission.
Economic impact
Decades ago, the US
lost most of the world’s market share of commercial satellite launches to
Europe and Russia US companies launch almost exclusively for the US US
balance of payments, the US
What’s next
Elon Musk has indicated that he is not interested in building re-usable
winged vehicles, but that he is interested in recovering his boosters for
re-use, which he admits is a really tough challenge. The primary current
problem being faced is structural breakup of the first stage due to dynamic
pressure during entry. The side boosters of the Falcon Heavy would be good
prospects for recovery attempts as they would have relatively lower velocity at
stage separation. It may be possible to prevent damage during entry by using
attitude control to keep the stages aligned with the entry flight path,
stiffening the structure of the rocket bodies, and protecting the engine
compartments. Recovering the second stage of the Falcon 9 would require full
re-entry protection, but this stage is easier to stabilize during entry. The
core stage of a Falcon Heavy would be the hardest to recover due to its high
speed and length.
Musk’s National Press Club announcement of September 29th, 2011, shows
that the recovery plan includes having the first stage actually reverse course
and land vertically back near the launch pad. This means the rocket has to
cancel all eastward velocity and gain westward velocity, as well as
decelerating the vertical component during landing.
This would require a significant amount of delta-V that would reduce
the payload capacity of the Falcon 9, but with the Falcon Heavy, which has
extra payload capacity and where at least two first stages would be recovered,
the payload size reduction may not be that big an issue. If a launch site could
be found with an island in the right location downrange, payload capacity could
be gained while still recovering the stages. The actual landing would take
place with extendable landing legs on a level surface (without a flame bucket)
and would use only a single engine. SpaceX has posted a video of the proposed recovery
system.
We will not know how successful this system is until there is a
successful landing and evaluation of a stage’s condition. The first SpaceX
recovery concept was a water landing, which would have subjected the engines to
severe salt water corrosion. Since the current prices are based on no
recoveries, any recoveries should allow significant launch cost reductions.
SpaceX would presumably have to demonstrate a launch using the recovered stages
before a paid launch, just as it has already done with all of its vehicles.
Musk has publicly pledged to continue his efforts for both lowering
launch costs and improving capability, so the currently described version of
the Falcon Heavy is not likely to be the “last rung” in his launch ladder. With
53 metric tons of payload, the Falcon Heavy is not considered a “true” Heavy
Lift Vehicle (HLV), which is generally considered to be one that can lift 70
metric tons or more. NASA’s Space Launch System (SLS) is an HLV that is slated
for an initial version that can lift 70 metric tons and a later version that
can lift 130 metric tons.
SpaceX, however, has expressed confidence it could build a Falcon
“Super Heavy” launcher with a 150 metric ton payload capability and a cost per
flight of $300 million.
This results in a launch cost of $1,000 per pound, which is close to
the per-pound cost of the Falcon Heavy but with a payload three times larger —
a payload even larger than the largest payload projected for NASA’s SLS.
SpaceX President Gwynne Shotwell wrote the following in a letter
published in Space News (February 7, 2011):
“Based on SpaceX’s proven track record in scaling tenfold in thrust
from Falcon 1 to Falcon 9, we are confident we can scale tenfold again and
develop a heavy-lift launch vehicle with a 150 metric ton to orbit capability.
We can do so for no more than $2.5 billion, within five years, on a firm, fixed
price basis with payment made only on achieving hardware milestones.”
Musk was also quoted by Aviation Week (December 2, 2010):
“We’re confident we could get a fully operational vehicle to the pad
for $2.5 billion — and not only that, I will personally guarantee it,” Musk
says. In addition, the final product would be a fully accounted cost per flight
of $300 million, he asserts. “I’ll also guarantee that,” he adds, though he
cautions this does not include a potential upper-stage upgrade.
Musk has also made public statements about SpaceX plans to send humans to Mars
in the next 10 to 20 years. Landing humans on Mars will take much larger in-space
vehicles, some of which would require a 15 meter diameter faring which in turn
requires a 10 meter diameter booster. No currently proposed heavy lift booster
is this wide. Musk’s interest in Mars as a destination provides reason to
believe that he will attempt to produce a cost-effective booster capable of
launching Mars-bound, crew-carrying vehicles within 10 years.
Significant announcements from SpaceX can be expected as long as the
company’s successes continue.
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