Today we are in a period of rapidly expanding private space services. There has been a long tradition of private satellite manufacture and related services, but given the roster of launch vehicles that sector saw limited growth and a limited customer base. Now, with more affordable launch options and the ability to launch very small satellites the potential customer base has expanded dramatically. Moving forward, space services must diversify by first focusing on services that provide a concrete benefit Earthside.
I see several areas with profit potential, in various stages of readiness: in-space refueling, satellite maintenance, orbital transportation, beamed power, adventure tourism / private spaceflight and resource harvesting. Let's take a look at each of these after the jump. Note that launch services are not included here; I see that as a current and successful market and as a necessary step before any of these areas could become profitable.
The easiest item on the list is adventure tourism. Russia (via Space Adventures) already sends paying customers into space (including NASA astronauts) and has sent seven private individuals to the ISS. It is worth noting that all of those people object to the label of 'tourist', and with good reason. Each was required to complete rigorous flight training and qualify as trained crewmembers; many performed experiments while in space for their parent company or other entities. It appears the preferred term is private researcher, private astronaut, etc. Obviously there is a market for this among people with a lot of money to burn and a strong desire to go to space; Space Adventures plans to resume paid flights to ISS soon and could see revenues in excess of $100 million per year.
Virgin Galactic, Blue Origin and XCOR among others plan to offer suborbital flights. This would be a ~10 minute flight to 100km+ altitude, just enough to qualify one as an astronaut under current rules. I would argue that this is clearly space tourism. Nothing wrong with that, but it's a big gap between this and making orbit. Still, with ticket prices under $1 million there is a much larger potential market; Virgin Galactic alone has sold over 700 tickets before flights have even started (an estimated $80 million in deposits).
SpaceX and Boeing both have crewed orbital capsules in the works and both have plans to offer private seats. SpaceX has a flight-proven capsule and is in the process of human-rating (with $2.6 billion of NASA funds). Boeing is still in design, but they have the resources (including $4.2 billion of NASA funds) and expertise to succeed. Ironically, flights on Boeing's CST-100 craft are likely to be cheapest when launched atop a SpaceX Falcon 9. Flights on Dragon v2 are expected to cost $20 million per seat for a full flight of 7 seats. Costs for the CST-100 are harder to pin down. NASA reports that the program will average $58 million per seat, which works out to about 110 seats over the course of the commercial crew program. That would be roughly two flights of seven crew per year for eight years.
Right now the only orbital destination is the ISS, which limits the demand for seats to perhaps two flights per year. Within the next decade, Bigelow Aerospace intends to launch one or more private space stations; crew requirements will depend on how much station volume is sold and to whom, but could raise demand to as many as eight crew launches per year ($1.1 to $1.8 billion). It is also possible that the ISS will be disassembled, with the Russian orbital segment reconfigured into a permanent Russian station. American and international components in the USOS cannot continue in orbit without services provided by the core Russian modules, so either the segment will be deorbited or a new core and propulsion module will be launched to create a majority-US station. If that is done, NASA is considering moving the station to EML1. In any case, this would eliminate commercial crew services to ISS as Russia would almost certainly continue using Soyuz for crew and NASA would use Orion. Other nations, particularly China and India, may decide to launch their own space stations and perhaps rent space or allow private guests; this does not seem likely in the next decade but is possible.
Next up: in-space refueling. The first and most obvious customer is NASA; an orbital fuel depot would allow them to launch satellites on smaller LVs or launch larger satellites, allowing a choice between savings on the LV and increased capabilities on the spacecraft. That could mean buying an Atlas 401, Zenit, Soyuz, H-IIA or Falcon 9 instead of an Atlas 551, Ariane 5, H-IIB or Delta 4(5,4). Perhaps less obvious, Russia would see a significant benefit from a LEO depot in the plane of the Baikonur launch site. Vehicles would refuel in order to plane-change to an equatorial orbit for GEO deployment. Further into the future a fuel depot would be essential for the smooth operation of tugs and satellite tenders, serving as a buffer between fuel launches and fuel used in missions.
I think the current leader is Boeing with their in-development ACES vehicle using integrated fluids management. However, they are focused on LOX/LH2 propellant; few customers today have cryogenic upper stages. Hypergolic fuels require a different set of technologies and would most likely require shipping expendable supplies of a pressurant, either nitrogen or helium, but they have a larger potential market right now as hypergolics are typically used for satellite stationkeeping and orbit changes. The third fuel category is inert gases (argon, xenon) for ion engines; these can be stored as compressed gases or cryogenic liquids.
I think a near-term possibility is simply to ship water. It is dense, relatively inert and can be used as a life support consumable or as a propellant after electrolysis. It has a high surface tension and can be wicked out of a bulk tank in microgravity without pressurants or membranes. There are cubesat-scale thrusters available today that separate water over time, accumulating a charge of gaseous O2 and H2 using small amounts of power, then ignite that fuel in a high-efficiency engine. If future satellites were to adopt this technology for RCS and stationkeeping then they could nearly double their Isp while eliminating toxic fuels and cutting down to a single storage tank. Beyond the near-term possibilities, a water depot operator would be able to buy water from any LEO cargo provider as well as any asteroid mining company, relying on the proven launch capabilities today while safely and cheaply allowing for a riskier but cheaper future supply.
The remaining markets generally rely on an orbital fuel depot and many rely on easy manned access to space, so the first two areas discussed above are 'force multipliers' for the commercialization of space. I will combine the categories of satellite maintenance and orbital transportation next as they have similar operational requirements, even though they can have distinct customers.
The reason an orbital tug is attractive is that rockets can launch much heavier payloads to a low orbit than they can to a high orbit. If the rocket does not have to launch hardware for moving the payload to a higher orbit then mass is saved, allowing the customer to use a cheaper launch vehicle or to launch a heavier payload for the same price.
An orbital transport provider would use a spacecraft, commonly called a tug or taxi, to deliver a payload to a different orbit. Ideally this vehicle would be reusable. This has been an area of active research since the 60's if not earlier, but I would argue that the ESPA ring and particularly the LCROSS mission represent a major step forward. The next step in this vein is probably the SSPS / Sherpa proposal from Spaceflight Inc for smaller payloads. Larger payloads could be handled by a Boeing ACES, Lockheed Martin Jupiter, ISRO PAM-G, RKK Energia Parom or Ad Astra concept vehicle. Of those, only Boeing and ISRO are known to be testing hardware. As far as I know, Boeing is the only contender investing heavily in microgravity cryogenic fluid management; this is a serious roadblock to in-flight refueling, which is a fundamental requirement for reusable tugs.
Ion-powered vehicles are popular concepts since they are so fuel-efficient. One drawback is that an ion-powered spiral from LEO to GEO exposes the payload to the Van Allen radiation belts. A possible solution is for the tug to provide radiation shielding for its payload during transit.
The Jupiter proposal is an example of a reusable tug with no depot. Tug fuel is included on the same launch vehicle as the payload. This is an efficient approach that minimizes risk in the near term. On the other hand, using a depot would allow the tug operator to purchase fuel at the lowest available launch cost and free up all available capacity on the customer's launch vehicle for their payload.
Satellite maintenance is in some ways an extension of an orbital tug. Either fuel or replacement parts are taken from LEO to the satellite's orbit. The craft is fueled, repaired or maintained in position while still operating. The largest market for this service is probably geosynchronous communication satellites, where receiving extra RCS fuel could extend their service lifetime by a decade or more. NASA has done in-space research on this subject under the Robotic Refueling Mission on ISS. Vivisat and MDA have both done work on commercial refueling services, with MDA's entry including a manipulator arm that could be used for ORU-style maintenance as well as refueling.
Adding the ability to swap out solar panels and transponders, a satellite bus could double its profitable lifespan. To take advantage of this the satellite needs to be designed for on-orbit maintenance from the beginning, similar to the way the ISS uses orbital replacement units.
An extension of this would be for a tug to retrieve a satellite and deliver it to a manned repair facility. Satellites with power or communication failures could be rescued or recovered this way, examined by human technicians, then possibly repaired and returned to their service orbit depending on the damage. Right now satellite operators are required to provide their own end-of-mission contingency; in most cases that means reserving a significant chunk of RCS fuel to either deorbit or move to GEO parking orbit. Having a service tug available might allow operators to eliminate that reserve, extending the useful life of satellites (potentially by several years) at the cost of a single tug mission.
In the longer term, most satellites at end of life are still structurally sound. If we start designing satellites with fully-replaceable parts then there is no reason why a GEO sat couldn't be retrieved, refueled, given new power hardware and upgraded navigation and outfitted with a new set of transponders before being placed back in GEO, all automated or remote-controlled. The basic structural bus might last many decades. Even for satellites currently in graveyard orbit, if a suitable crewed facility was available then the owners of those craft would gain considerable value from that mass by refitting or selling the bus to be refitted by someone else.
Resource harvesting is a major draw for investment in space. Two main classes of resources are important in the near term, with three additional classes becoming important in future decades.
First up is water. It is perhaps the easiest substance to extract and purify and is thought to be abundant in chondrite asteroids. It is also present on the Moon, Mars and Ceres, though Mars is an unlikely source of water for shipment back to LEO. Water can be split to provide oxygen for breathing gas or oxidizer and hydrogen for propellant or other chemical uses (Sabatier process for life support or as a fuel cell input for electricity). There is an immediate market for potable water on the ISS and will presumably be a strong market at any future space station. Water depots are another potential customer assuming future satellite RCS transitions from hypergolics to electrolyzed water.
Next is rare elements, mainly platinum group metals. These are abundant in metallic asteroids, with asteroid 16 Psyche alone representing perhaps 110 billion tons of PGM (at 5 PPM). Early efforts will probably focus on bodies of 100-200 meter diameter rather than 200+km diameter, but the supply is out there. Some detractors claim that dumping tons of precious metals on the market will crash prices. Certainly prices will go down if a new and abundant supply comes online, but platinum's value comes from more than being shiny. There are many potential uses for platinum that are not cost-effective today. A massive increase in supply would lead to a technological expansion of similarly massive proportions. Regardless, there is an immediate market for PGMs and other rare elements on Earth; any operator that can land their payload safely will be able to sell it easily any time they choose.
The latter categories are a bit similar. First is construction materials like iron, nickel and other metals (aluminum, calcium, magnesium, titanium, cobalt, tungsten) that might be used to build structural parts and pressure vessels. Next is semiconductors and dopants, mostly silicon but including gallium, germanium and indium plus tin, arsenic, antimony, aluminum, phosphorus, boron and gallium. These would be used to build solar panels, LED lights and potentially microprocessors. Last is whatever is left over, the slag from other processing. This is generally useful for radiation shielding (as is water) and would be used for manned craft and facilities outside Earth's magnetic field. A fourth category might be carbon and any trace nutrients required for plant life, though these materials would be separated as part of the refining process for structural metals and high-purity semiconductors.
All of the latter categories require a significant presence in orbit with the capacity to manufacture complex parts. This is definitely not a near-term environment, so the 'early days' operators are reduced to just water and platinum as potential products. Given the significant complexity involved in extracting platinum, I expect water to be the first non-Earth resource sold.
Last on my list is beamed power, which arguably does not belong in an 'early days' roundup. The usual example is a solar power satellite network beaming power down to the surface. Other uses include long-range power (probably laser) to a vehicle or satellite for propulsion and short-range power (probably RF) between a carrier satellite and payload cubesats or other small craft.
The SPS concept has been thoroughly explored over the decades. All necessary technologies exist and have been demonstrated. Environmental impact studies have been performed. The main barrier now is launch costs, which can be overcome by low-cost reusable LVs and / or the use of material harvested in space. As long as human civilization continues to use electricity there will be a market for SPS power on the surface. As the impact of human-induced climate change grows, the demand for power that does not threaten our species will continue to grow.
This kind of baseload power is further into the future but there are near-term applications. In particular, electric space tugs would benefit from a constellation of modest-sized SPS craft. Instead of carrying large solar panel arrays, a tug could carry just the rectenna and power conditioning equipment necessary to receive beamed power. This hardware would be lighter and much more resistant to radiation, allowing for a longer service life for LEO-GEO tugs. The reduced mass would make the tug more fuel-efficient, while a proper network of satellites would allow full-time operation of the tug's ion engine without requiring large battery packs. This same network of satellites could provide peak power to other assets with intermittent high power demand, particularly to a low-orbit space station that periodically does energy-intensive materials processing or uses electric engines for reboost / CAM. A further set of customers might include satellites intended only for short missions; formation flights of cubesats for example would benefit from requiring a smaller mass (and lower price) of rectenna than they would have required in solar panels.
A 'retrofit' option would be an SPS network that beams power using IR or visible lasers rather than RF. The specific frequency would be one that solar cells can efficiently convert. The SPS would simply lase the solar panels of the client craft, providing power when the sun is not available or increasing power while the craft is lit. This is significantly less efficient than RF but it would work on existing satellites and at longer ranges.