BIS-RS-2014-28 The Disruptive Potential of Subsonic Air-Launch David J. Salt Telespazio VEGA Deutschland GmbH Europaplatz 5, D-64293 Darmstadt, Germany; +49 (0)6151 8257-0 [email protected] ABSTRACT This paper tries to show that big launch vehicles may not be required to enable big space operations. It first highlight the essential role of space launch in enabling all space operations and indicates the dominant role that ‘customer’ demand has played in both enabling and constraining its development. It then discusses the advantages and drawbacks of a subsonic air-launched reusable launch vehicle (RLV); comparing and contrasting them against a wide range of other possible launcher concepts. In doing this it highlights the unique evolutionary opportunities that this concept has to offer and provides some insight as to how these may be realised and enhanced via existing technologies. Finally, the paper highlights the radical improvements in operational architectures afforded by such a vehicle. It shows how an RLV with a relatively modest launch performance of less than 5t to low Earth orbit could be capable of supporting almost all current and future launch demand by forming the key element of a fully reusable space transportation infrastructure. KEYWORDS: ACES = Air Collection & Enrichment System LEO = Low Earth Orbit CR = Collection Ratio Mg = Metric tonne ELV = Expendable Launch Vehicle Mn = Mach number GEO = Geosynchronous Earth Orbit SSTO = Single Stage to Orbit GTO = Geosynchronous Earth Orbit TSTO = Two Stage to Orbit IRR = Internal Rate of Return RLV = Reusable Launch Vehicle kg = kilogram 1. THE LIMITS TO GROWTH realisation. Given the importance of markets in the development of commercial activities, this assessment HE frequency and complexity of space operations T has evolved relatively slowly over the last three also considers how such factors may also influence decades and is certainly much reduced in comparison their growth and sustainability. with the first two decades of the Space Age, which began more than half a century ago. The reasons for this i) Current Constraints ‘phase change’ can be easily understood when one Current space activities range from pure science considers the changes in both political and economic missions through to civil and military applications like drivers that control most space activities, especially communication, navigation and observation systems. those involving human spaceflight. Nevertheless, growth and evolution in all these areas is The past five decades of space activity have, to a limited by a few key factors: large degree, been driven by a few specific issues such government priorities and constraints; as national security and conservation of the industrial competition from terrestrial alternatives; base. In contrast, the slow growth of commercial low market ‘elasticity’ (i.e. lower prices ventures has been due mainly to market and financial stimulate only limited market growth); constraints, rather than any basic limitation of the launcher cost/availability/reliability. available technology. As a consequence, the diversity The first factor is important because the growth of and intensity of spaceflight operations have also been space activities is still dominated by government paced by these trends, though the manner in which they programmes, both civil and military. Communication are performed, on both the ground and in space, has satellites represent the nearest thing to a truly been radically improved by the phenomenal advances in commercial market sector, but government funding still computing and software over this same period. underpins much of their basic R&D while the second and third factors have placed significant restraints on 1.1 The Current Space Paradigm & Potential of their growth and evolution, as witnessed by the NewSpace problems of commercial ventures like Iridium, We first consider future possibilities to identify the Globalstar, ICO, SkyBridge and Teledesic. factors that may either prevent or severely restrain their Salt 1 Reinventing Space Conference 2014 To put the situation into perspective, Figure 1 shows aim being to reduce specific launch costs by an order of a breakdown of the global space industry’s annual magnitude to below about $1000/kg to LEO, the point revenue, which was $304 billion in 2012. However, this where significant growth in all market sectors is was still less than the annual turn-over of a single expected to be triggered. successful commercial company like Wal-Mart [RD.2], Nevertheless, it is important to realize that the which was founded in 1962 but has managed to NewSpace paradigm is not solely restricted to outgrow the entire world space industry by servicing entrepreneurial start-up companies. A more thoughtful vastly bigger and established markets to give a turnover definition would also include groups working within of $445 billion in 2011. established companies, such as Boeing, Lockheed- Martin and Orbital Sciences, who are also seeking to stimulate existing and new markets by applying novel technologies and commercial practices such as fixed- price, rather than cost-plus, contracts. 1.2 NewSpace and the Realities of Space Access As launch services are one of the most significant constraints on the growth of future space operations, we now consider the significant improvements in vehicle design, operation and economics that will be required and the ways in which these could be realized. It has long been recognised that the only way to achieve significant improvements in space access is via reusable launch vehicles (RLVs) instead of expendable Figure 1. Global Space Activities, 2012 [RD.1] launch vehicles (ELVs), because they offer: major reductions in marginal costs, as expensive ii) Future Potentials components tend not to be discarded after use; better amortisation of investments, as costs can A wide range of future space-based activities and 1 be spread across more users; associated business opportunities have been discussed for many decades (e.g. space manufacturing facilities, higher reliability and safety, due to the intrinsic solar power satellites) but their realisation has also been value of the vehicle. limited by a few key factors: Unfortunately government efforts to field such systems have, to date, either missed many of their large investment requirements; original goals (i.e. Shuttle) or been outright failures (X- operation and utilization cost uncertainty; 33/VentureStar, X-34, etc.). Moreover, commercial market demand and ‘elasticity’ uncertainty; efforts to develop such systems have been hampered launcher cost, availability and reliability. because their development costs are difficult to justify Given these circumstances – and in the absence of a against potential markets, for example: major government imperative, equivalent to that which many studies estimate it will cost $10-20 billion justified Apollo (i.e. the Cold War) – it has become to field an operational system; clear to many that the current paradigm will not lead to the existing markets are insufficient to justify any significant growth of space activities in the their development because they have limited foreseeable future. As a consequence, a number of growth and ‘elasticity’3 (i.e. lower prices NewSpace ventures have begun to emerge2 that stimulate only limited market growth); represent an attempt to change the paradigm by placing the new markets that could justify their greater emphasis on entrepreneurial rather than development are far too uncertain and government activities. speculative. NewSpace ventures believe that the best way to Such factors show that both market and financial change the paradigm is to stimulate existing and/or new issues play just as important a role as the obvious markets in order to drive and sustain their growth, technical ones. They also explain why NewSpace primarily through the power of commercial enterprise. ventures have chosen to begin by developing RLVs to Moreover, as launch issues are seen as the common service sub-orbital markets, which demand significantly factor that limits both current and future growth, most less of an initial investment, with many estimating that have chosen to address this issue first; their ultimate only $100m-$200 million will be required. 1 For example, the Commercial Space Transportation Study (CSTS) 3 performed a comprehensive review in 1994 of all current and Space market elasticity is difficult to estimate due to the relatively foreseeable markets [RD.3] small size and low diversity of current markets, though studies 2 Summaries and links for all current ventures are at such as the CSTS [RD.3] and the NASA ASCENT Study [RD.4] (http://www.space-frontier.org/commercialspace/) have derived tentative estimates. Salt 2 Reinventing Space Conference 2014 Nevertheless, it should be appreciated that cost isn’t altitude of 555 km. Since then, the only operational air- everything and that frequent flight availability and a launched rocket has been Pegasus, which was timely and efficient integration process are just as developed by the Orbital Sciences Corporation as a important. A good example of this is NASA’s Get commercial satellite launch vehicle and first flown on Away Special (GAS) canisters [RD.5] that were priced 5th March, 1990, with 42 launches to date. on the order of $100/kg to LEO but, because of the long Most air-launch concepts carry the rocket external and complex Shuttle integration process, were to the launch vehicle, either on top