Graham Warwick/WASHINGTON DC
NASA has awarded contracts to four small businesses to develop concepts for providing back-up access to the International Space Station (ISS).
The three-month study contracts, totalling just under $1 million, are targeted at emerging low-cost launch systems. Separately, similar contracts have been awarded to established launch service companies.
NASA's Alternate Access to Space Station programme is intended to provide assured, on-demand cargo access by using commercial launch services to back up the primary resupply vehicles: Space Shuttle, Russia's Progress and European and Japanese transfer vehicles.
Study contracts have been awarded to Andrews Space &Technology, HMX, Kistler Aerospace and Microcosm. Kistler and Microcosm are offering solutions based on low-cost launch vehicles still under development. Andrews, meanwhile, is proposing a "Progress-like" commercial logistics module which could be carried into orbit by an existing or emerging launch vehicle.
The contingency resupply service under study would be capable of launching within a week if the primary cargo delivery methods were unavailable, NASA says. The agency has established "light" and "heavy" payload delivery requirements. Although there is no stated requirement, at least two of the bidders will offer the capability to return cargo from the ISS.
The "light" requirement is to deliver a minimum 135kg (300lb) cargo to the vicinity of the station, while the "heavy" requirement, at 1,800kg, is equivalent to the payload delivery capability of the Progress tanker.
Kistler is offering a solution based on its planned fleet of five K-1 reusable launch vehicles, which the company says would be capable of docking with the ISS, delivering more than 1,800kg car-go and returning 900kg to Earth.
Microcosm is offering two versions of its Scorpius low-cost expendable booster: the 225kg-payload Sprite "mini-lift" and larger Antares intermediate-lift vehicles.
Neither would be able to dock with the ISS, requiring a vehicle to transfer the cargo to the station. Microcosm is working with Constellation Services International, which plans to commercialise a Russian space tug.
Andrews, meanwhile, is pursuing a commercial logistics module which would be carried by existing or emerging launch vehicles and would transfer light and heavy payloads directly to the ISS. The heavy version would be reusable, and could return cargo to Earth.
HMX is a consulting company run by two former executives of Rotary Rocket.
Whether any of the four companies can meet NASA's requirement for launch service availability by the end of 2003 will depend on financing. Both Kistler and Rotary Rocket have halted work on their launch vehicles while they look for additional funding.
Microcosm is continuing work on its Scorpius family and plans to test-launch the suborbital SR-XM in November. Funding permitting, this will be followed by the commercial, suborbital SR-M, which is the basic building block for the Sprite launch vehicle.
Source: Flight International
