Update 6-1-18: see red text edits embedded below
------------------------------------------------------------
Update 6-16-18: see blue text at end of article, after the figures
------------------------------------------------------------
This article compares and correlates unit costs for
launchers, mostly those used
commercially. These data are based upon
reported payload capacities and launch costs found in the literature. The format is cost per unit delivered payload
mass, on the very important assumption
that the launcher flies fully loaded. All
figures are at the end of this article. Click on any figure to see any or all of them enlarged. You can close that view box and be right back to viewing this article.
Results are reported in millions of dollars per delivered
metric ton, and in dollars per delivered
pound. To estimate the unit cost when flying
at less than full load, simply divide
these unit costs by the fraction of fully-loaded that you intend to fly.
Scope includes the launchers used in the competitive
satellite launch business, plus a few
launchers that were used, but not
competitively, and the US Space Shuttle
as representative of a large spaceplane.
Some of these launchers are no longer in service. However,
the correlation results are used to predict unit costs for the NASA SLS
block 1, just for comparison.
Data, Sources,
and Results for “Standard Low Earth Orbit”
“Standard Low Earth Orbit” is 23 degree inclination out of
Cape Canaveral, Florida, to a 200 km orbit altitude. This is what the reported payload delivery
capabilities in the literature refer to.
These data are for one-way delivery of payload using a simple payload
shroud, not a recoverable capsule, except for the Space Shuttle. As researched, those data are:
Of these, the US
Space Shuttle, the Titan IVB, and Falcon-1 are no longer in service. There is a demonstrated history of
reliability problems with Proton-M. The
Titan-IVB was retired in 2005. The
Falcon-1 retired no later than 2012. The
Space Shuttle retired in 2011. The
prices shown are for fully-expendable flights in the case of Falcon-9 and
Falcon-Heavy. There should be some small
price break for flying reusably at reduced payload with these two launchers, although how much is but speculation.
The trends of unit cost per delivered metric ton (flying
fully-loaded) are given in Figure 1.
Figure 2 shows unit cost per delivered pound. Data are grouped and correlated as
“competitive”, “non-competitive”, and “spaceplane. The “competitive” launchers correlate flying
fully loaded as:
Unit
cost $M/metric ton = 10.557 e^(-0.033 Wp)
where Wp = delivered payload, metric tons
Unit
cost $/delivered lb = 4787 e^(-0.033 Wp) where Wp = delivered payload, metric tons
The launchers marked “competitive” all compete in the
commercial (and military) satellite launch businesses, with market share in part depending upon
price. The launchers marked
“non-competitive” never competed commercially,
and thus were not subjected to severe pressure on price. The model for these assumes the same -0.033
Wp factor, and uses a coefficient that
forces the curve through the average of the Titan IVB and Delta IV Heavy data
points:
Unit
cost $M/metric ton = 39.1 e^(-0.033 Wp) where Wp = delivered payload, metric tons
Unit
cost $/delivered lb = 17,720 e^(-0.033 Wp)
where Wp = delivered payload,
metric tons
This model was extended to 70 metric tons payload to
estimate what should be expected for NASA’s SLS block 1 as shown in the figures
($3.878M/m.ton and $1759/lb). That
calculation corresponds to an expected launch cost of $271M, when NASA’s actual launch cost estimate is
$500M, and its critics estimate twice
that. So instead of only 3 times more
expensive than Falcon-Heavy (otherwise comparable in payload) as predicted by
the correlation, SLS block 1 is likely to
be at least 6 times more expensive, and
it might even be 12 times more expensive.
Update 6-1-18: the latest NASA estimates for launching SLS block 1 have grown to about ~$1-2B per launch. Its critics put that closer to $4B. For a 70 metric ton payload, that's $14-56M/m.ton, or $6500-$26,000/lb. The range depends upon whose estimates you believe more. That falls somewhere halfway between all the other launchers and the space shuttle. SLS is well on its way to being the most costly launch vehicle in human history.
The Space Shuttle (marked “spaceplane”) is quite
different, in that the delivered payload
is but a small fraction of the mass of the recovered vehicle. All the others are one-way trips to
space, with the delivered payload
encased in a shroud. There are no
recovered capsules delivered by these launchers.
The spaceplane model for the Space Shuttle assumes the same
-0.033 Wp factor as the “competitive” launchers, with a coefficient that puts the curve
through the data point for the Shuttle:
Unit
cost $M/metric ton = 131 e^(-0.033 Wp) where Wp = delivered payload, metric tons
Unit
cost $/delivered lb = 62,580 e^(-0.033 Wp)
where Wp = delivered payload,
metric tons
Re-Scaling Results
for Delivery at the International Space Station (ISS)
I used the payload reduction fraction seen with the Space
Shuttle as a constant applied to all the launchers still in service, for estimating unit cost performance
delivering to the ISS. The ISS is
located at a higher inclination and a higher orbit altitude. For the same launcher technical performance, a launcher’s max payload capability must be
reduced when reaching for the more demanding destination.
Flying with a 7 person crew,
the Space Shuttle is listed as 24 metric tons to standard low Earth
orbit. It could deliver as much as 27.5
tons, but only with a smaller crew and
less supplies. Flying with a 7 man
crew, its capability to ISS is reduced
to 16 tons. That is 2/3 of the standard
low Earth orbit capability with the same crew and supplies. Applying this 2/3 factor “across the board”
with the same launch prices produces Figures 3 (per ton) and 4 (per pound)
below.
I correlated unit cost estimates to ISS only for the “competitive”
launchers that are still in service.
These are (of course) somewhat higher than for “standard low Earth
orbit”, because payload capability is
lower, while launch price is not. This for one-way payload delivery using a
simple payload shroud, not a recoverable
capsule. That model is:
Unit
cost $M/metric ton = 15.428 e^(-0.048 Wp)
where Wp = delivered payload,
metric tons
Unit cost
$/delivered lb = 6996 e^(-0.048 Wp) where Wp = delivered payload, metric tons
Estimating the
Effects of Reusability
I based this estimate on what Falcon-9/Cargo Dragon has
demonstrated to ISS with re-use of first stages, when loaded to max cargo for ISS, versus what I estimate the fully-expendable
deliverable payload is to ISS. The fully
expendable estimate is 15.2 metric tons to ISS.
A fully-loaded (for ISS) Cargo Dragon is 8.8 metric tons. That ratio is 0.5789, and I assume it applies to Falcon-Heavy for
its payload delivery to ISS with re-use of first stage cores. The results are given in Figure 5, for both full price and for an arbitrary
modest price break: 80%-of-full-price, representing savings from re-use.
Estimating What SLS Block
1 Might Really Do (Standard Low Earth Orbit)
SLS Block 1 is said to deliver 70 metric tons to standard
low Earth orbit. NASA says it expects
each launch to cost roughly $500M.
NASA’s critics say each launch might cost nearer $1000M = $1B. Those data correspond to $7.14-to-14.28M/delivered
metric ton or $3239-6478/delivered pound (flying fully loaded).
The “non-competitive” launcher correlation predicts for SLS
Block 1 a unit cost of $3.878/delivered metric ton or $1759/delivered pound
(flying fully loaded). Falcon-Heavy has
an almost comparable payload (63.8 vs 70 metric tons), with unit costs of $1.411M/delivered metric
ton or $640/delivered pound (flying fully loaded and fully expendably). SLS will never be reusable, as that was never considered as a design
requirement.
SLS is expected to fly only once a year, and not until 2019 or 2020. Falcon-Heavy flew its maiden test flight in February
2018. It is scheduled to fly at least
two more times in 2018.
Update 6-1-18: as indicated above, even NASA's own cost estimates for an SLS launch have grown dramatically, as have the estimates of its critics. It will come nowhere close to what the non-competitive launcher trend predicts, being higher by a factor closer to 10 than 3. This is only opinion, but one would be tempted to say that this travesty is exactly what you should expect from corporate welfare mandated upon NASA by a Congress interested only in "pork".
Other Launchers to
Watch For (That Are Not Yet Flying)
There will be an Ariane 6.
Long March 5 may or may not be flying yet. United Launch Alliance is designing a new
heavy lifter to be called Vulcan. The
Jeff Bezos organization Blue Origin is designing a heavy lifter to be called
New Glenn. Spacex is working on a design
called BFR which will be a super-heavy-lifter with a fly-back first stage
combined with a second stage that is also a reusable spacecraft.
Final Note: Falcon-9 Cargo Dragon to ISS
Full price for a Falcon-9 launch is $62M. This can send to ISS a Cargo Dragon totaling
8.8 metric tons. Of that, only 3.310 metric tons is actual deliverable
cargo. Using that 3.31 tons, the effective unit costs for delivery to the
ISS are:
$18.73M/delivered
metric ton = $8495/delivered pound
Given the same 80% of full price with reusability, as was used above, these data reduce to:
$14.98M/delivered
metric ton = $6796/delivered pound
Compare those with what the Space Shuttle costs were, delivering 16 metric tons to the ISS at $1.5B
per launch:
$93.75M/delivered
metric ton = $42,517/delivered pound
These are the best guesses I have for Enhanced Cygnus on
Atlas V 551, and they are not
accurate. The max deliverable mass to
ISS is 12.34 metric tons, which has to
be larger than the loaded Cygnus. Data
gleaned from multiple sites on the internet says the max payload to ISS inside
the Cygnus is 3.5 metric tons max.
Cygnus cannot return to Earth.
Each launch is $153M. Those unit
costs are thus crudely:
$46.M/delivered
metric ton = $21,000/delivered pound
I have no reliable data on the cargo version of Soyuz, riding the R-7 rocket. Best guesses are max 2.4 metric tons of
payload in the capsule, and a launch
cost on the order of $65M. Those unit
costs are:
$27.1M/delivered
metric ton = $12,300/delivered pound
Thus, cargo Dragon on a Falcon-9
appears to be the most cost-effective means to deliver self-maneuvering and
self-rendezvousing cargo to the ISS, of
all the vehicles that have done this task.
Prior Similar Articles
This article replaces earlier postings on this site. The best of the older postings is “Access to Space:
Commercial vs Government Rockets”, dated August 7, 2015. That
one compares multiple rockets with the best inflation-corrected costs I could find
or devise. The one prior to that was “Revised
Launch Cost Update” dated September 13, 2012.
It refers in turn to “Revised, Expanded Launch Cost Data” dated May 26, 2012. That
one in turn was a revision to the original “Launch Cost Data” article dated January
9, 2012. But this current posting is the best, with the latest versions of the rockets, and the most current costs I could find. I did not inflation-correct costs from 2016 to
2018 values.
Figures Follow:
Figure 1 – Unit Cost Comparison (per ton) to Standard Low
Earth Orbit
Figure 2 – Unit Cost Comparison (per pound) to Standard Low
Earth Orbit
Figure 3 – Unit Cost Comparison (per ton) to ISS
Figure
4 – Unit Cost Comparison (per pound) to ISS
Figure 5 – Unit Costs for Falcon Vehicles as
Payload-in-Shroud to ISS with Re-Use
Update 6-16-18:
The competitive launcher curve-fit to LEO is $M/m.ton = 10.557
e^(-.033*Wp) where Wp is the metric tons of payload actually delivered from
within a payload shroud. It was derived
for a variety of commercial launch vehicles,
including Spacex Falcon-9’s whose boosters were never re-flown more than
twice, if at all. Most were not reused.
From Spacex’s website,
posted prices and payloads-to-LEO for vehicles not flown reusably are
$62M for a Falcon-9 carrying 22.8 metric tons,
and $90M for a Falcon-Heavy carrying 63.8 metric tons. These correspond to curve-fit unit price predictions
of 4.9748M/m.ton and 1.2858M/m.ton,
respectively.
Using this and the payload,
back-predicted launch prices are $113M and $82M, respectively,
compared to $62M and $90M as posted. The discrepancy can be laid to the scatter in
the data generating the curve fit. It
isn’t all that large at +26% for Falcon-9 and -9% for Falcon-Heavy. But it is important to realize that predictions
made this way could easily be wrong by a factor of 2.
It is far too soon to be talking about what the launch price
of a BFR/BFS ought to be. However, ignoring that, and using this same correlation at the
claimed 150 metric ton payload deliverable to LEO for the 2018 9-meter diameter
version, the predicted unit price is $0.07478M/m.ton, and at that payload, the back-estimated launch price should be near
$11.2M. That supposedly is the price
Spacex would charge a customer to deliver his 150 metric tons of cargo to LEO.
I have estimated elsewhere on this site that this 9 meter
diameter version of the BFS second stage requires 6 tankers to fully refuel its
tanks with 1100 metric tons of propellant (80% liquid oxygen, 20% liquid methane), enough for a one-way trip to a direct
aerobraked Mars retropropulsive landing, with 150 metric tons of payload. That’s seven launches for each BFS that departs
for Mars, totaling $78.4M in direct
launch costs for each BFS embarking on that trip.
Assume for the sake of argument the wild guess that
~$10B are left to spend making this design flight-ready for the Mars trip. Assume also as another wild guess that
another ~10B are needed to fully develop and field test-verify all the
equipment needed to sustain a small crew on Mars for 2+ years, and to emplace there the means to manufacture
propellant locally for the return home (1100 metric tons per returning BFS).
Assume also that one ship gets lost and destroyed trying to
make its landing. Could easily be 2 or
3, but assume it is only one.
Spacex’s posted plans call for 2 uncrewed BFS vehicles each
carrying 150 tons of cargo to land during the first Mars opposition, and 4 more the second opposition, with two of those carrying small crews and lots
of cargo totaling 150 metric tons. That’s
6 successful BFS flights to Mars, plus
the one we assumed lost, for a total of
7 attempts.
At the estimated aggregated launch cost of $78.4M per BFS
sent to Mars above, that’s $549M in
launch costs for the 7 attempts; just
under $0.6B. Add in the $20B to prove
out the vehicle and to prove out the hardware,
and you have a temporary base on Mars for under $21B! Remarkable!
And note how launch costs are miniscule compared to the hardware
development and verification costs that we have assumed. We could easily double or triple the launch prices, and not really affect this outcome.
Now, the predicted
$11.2M per BFR/BFS launch is for a matured,
well-proven design that flies routinely and reliably. That’s what the curve-fit really
represents. Right now this thing exists
only as a concept in presentations. A
whole lot of resources must be spent developing this vehicle and turning it
into that near-perfectly-reliable transport.
That what the wild guess of ~$10B is all about.
The same applies to both crew life support technologies and
most especially the on-Mars propellant production hardware. If that doesn’t work, the crew dies on Mars. There is no rescue, because without refilling on Mars, the BFS is a one-way trip. So the propellant production plant has to
work! And it has to produce some 1100
tons of propellant to refill that BFS which returns the crew, before their supplies run out. This is not a small piece of equipment! That’s what the other wild guess of
~$10B is all about.
So, no matter
what, you have ~$20B in vehicle and
hardware development and prove-out costs to amortize across the flights this
vehicle will make. The more it gets
used (for any missions, not just Mars), the lower that amortized impact on any one
vehicle.
If the only thing ever done with this vehicle is those 7
attempts at Mars, then there must be a
total of 49 BFR/BFS vehicles launched.
$20B spread over 49 vehicles is $408M per vehicle. That needs to be added to the
otherwise-mature launch price of $11.2M,
for about $419M per launch.
If you do missions to the moon in a similar way to
Mars, that’s another 49 flights under
the same assumptions otherwise, for a
total of 98 flights to amortize the development costs. That would be $204M per vehicle, for a total price of $215M per flight.
Now, if the same
vehicle gets routinely used to LEO, that’s
more vehicles over which to amortize the development costs. Say,
100 orbital deliveries, for a
total of 198 flights. That’s $101M amortized
per vehicle, for a suggested launch
price of $112M per vehicle.
This is the “mass production effect” in action. Unless somebody else foots some or all of the
development bills, I fear the BFR/BFS
vehicle launch price can never be as low as it could be. But then again, my curve fit may have been extrapolated too
far. We’ll just have to wait and see
what really happens. One thing is
sure: this thing will be way cheaper to
use than NASA’s SLS ever could be!
