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.
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.
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.
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