Since NASA’s Commercial Cargo, Commercial Crew, Space Launch System () and Multi-Purpose Crew Vehicle programs were initiated and co-existed in the organization that I led before retiring from the agency, I would like to clarify a few points that have come under recent criticism.
While there are scores of differing opinions of what our nation’s space programs should look like, decisions have been made with priorities set in the current space policy. Additionally, our international partners depend on stability and credibility in the U.S. space program to help set their own policies and priorities. In a balanced U.S. space policy, there is a logical place for each of these complementary programs.
The NASA Authorization Act of 2010, signed by President Barack Obama, established policy for the current commercial and human space exploration programs. This has been further supported through subsequent legislation. Driving unnecessary wedges between congressionally authorized programs endangers all of human spaceflight, and it is important to note that canceling one program will not necessarily result in redistribution to those remaining.
Some critics have differentiated between commercial and NASA-led programs. To clarify, all of these are NASA programs that have to satisfy NASA requirements. The major difference is in the procurement approaches. For commercial programs, requirements should not be overspecified or unnecessarily changed during development. During my time at NASA, I stressed streamlining common human-rating requirements for all programs that still protect for safety. What is acceptable for one should be acceptable for the other.
Currently, the most tangible commercial market beyond government needs is in sending space systems to and from low Earth orbit. A sustainable market for private human spaceflight to orbit has not been shown conclusively, but may develop over time. But for the foreseeable future, the anchor tenant for the human transportation market is government funded missions to and from the international space station. The question now is whether this capability will become fully operational before the current 2020 extension date for the space station, given the additional complexity of human safety requirements required for crewed missions compared with cargo flights.
With this timescale in mind, it is important to note that between the Commercial Orbital Transportation Services Space Act Agreements and the Commercial Resupply Services contracts to date, only about 30 percent of the demonstration and launch commitments have been accomplished and with significant delays. It seems premature to place additional reliance upon the commercial suppliers for all U.S. launch needs beyond the current cargo and crew programs. That said, this U.S. Earth orbit transportation capability is needed. But there is no indication that companies will be motivated to develop the heavy-lift vehicle needed for exploration beyond low Earth orbit with their own resources, while depending only on the government for business.
Another misconception is that human space exploration could be easily accomplished with existing launch vehicles. Countless studies over more than 20 years have shown that a heavy-lift vehicle over 100 metric tons to Earth orbit is needed to accomplish human exploration missions with a reasonable number of launches. More specifically, upper stages need to provide from 40 to 50 metric tons of beyond Earth orbit delivery capacity for these missions. Existing vehicles do not meet this requirement. To launch the mass needed for a single Mars mission, it would take many tens of launches using existing vehicles, which increases mission risk. There is a reasonable probability of losing one or more launches of the amount that would be required for a single Mars mission. With missions being assembled in space and launch windows occurring every six months, timing will be a challenge even using multiple heavy-lift SLS vehicles.
Another issue that is often not addressed is the volume needed for flight components sized for human missions. Payload shroud volumes and diameters of existing launch vehicles are too small for Moon or Mars landers or other flight elements.
The industry-led approach to transportation of cargo and people to space is in its infancy. It is having its own technical startup problems and delays, but it needs to succeed, and I believe that it ultimately will. Transportation of people into space is a huge step beyond transportation of hardware, and human exploration beyond low Earth orbit is a large step beyond that. But an informed argument for turning all of this over to an emerging transportation industry does not currently exist. NASA’s major role should be to lead development of systems for exploration and discovery, not routine transportation.
Doug Cooke is an aerospace consultant for Cooke Concepts and Solutions. He spent 38 years at NASA and is a former associate administrator for the Exploration Systems Mission Directorate. Cooke serves as an adviser to the Coalition for Space Exploration.