Nasa's manned-mission dilemma in post-Shuttle era
Mark Williamson examines the US space agency’s options over future manned missions.
When Nasa retired its Space Shuttle fleet this July, it effectively withdrew its capability to launch astronauts into space. At present, and for the next few years at least, the American space agency will be reliant on the venerable Russian Soyuz to launch its crews to the International Space Station. If you find this surprising, politically inept, or simply an example of bad management, you are in good company; space industry veterans, lunar astronauts and even the odd space journalist have seen this coming.
The issue of a ‘grounded space agency’ was a key topic at the 62nd International Astronautical Congress (IAC), held in Cape Town from 3-7 October, not least because it heralds a new era of commercial manned spaceflight. Nasa’s astronaut corps has been grounded before - for six years between the Apollo-Soyuz Test Project of 1975 and the inaugural Shuttle flight of 1981 and for shorter periods following the Challenger and Columbia incidents - but commercial options were not available then.
Today, however, with the help of government funding, a number of private space companies are developing vehicles designed first to carry cargo to the ISS, and, later, crews. The key word here is ‘later’: according to William Gerstenmaier, Nasa associate administrator for human exploration and operations, 2015/16 is the earliest the US can deliver crew to the ISS.
This presents Nasa with a choice on space transportation. Arguably the cheapest and most straightforward route would be to do what many space scientists and supporters of robotic missions suggest and eschew manned spaceflight. Apart from the obvious loss of face for a nation that placed the first humans on the Moon, there is the spectre of the sole supplier.
In April 2010, Nasa signed a contract with the Russian Federal Space Agency for six round-trip tickets to the ISS for $335m, which is about $55.8m per seat (the previous price had been $51m). When it made its next bookings in March 2011, the price had increased to nearly £63m (a 12 per cent annual increase).
The other major risk with a single source is the lack of redundancy, which was demonstrated by the failure of a Soyuz rocket carrying a Progress supply craft to the ISS in August. The similarity between the upper stage of the failed vehicle and the Soyuz variant used for crew delivery has delayed the next manned flight to November and raised the possibility of a reduced station crew. Again, the lack of a shuttle highlights the fragility of the supply line to the station which, incidentally, has been manned permanently since November 2000.
One alternative route, identified by Nasa several years ago in its Commercial Crew Development (CCDev) programme, was to seed-fund budding US commercial operators, which would at least keep its budget within national borders. The leading contenders are SpaceX and Orbital Sciences, although Boeing, Blue Origin, and Sierra Nevada have also received funding in a second round that runs until next year. Beyond that, funding is uncertain because of government cut-backs.
Nevertheless, SpaceX is planning to berth an unmanned version of its Dragon capsule at the ISS towards the end of this year, enabling Nasa Administrator Charles Bolden to declare that “it is months, not years, before the US has a domestic capability to take cargo to the ISS”.
In parallel, and ostensibly as part of a broader space exploration programme, Nasa is trying to develop a new crew capsule and launch vehicles under a more traditional supply contract. In September, Bolden announced that the $18bn Space Launch System (SLS) would make its first unmanned test in 2017, carrying the $6bn Multi-Purpose Crew Vehicle (MPCV) currently under construction by Lockheed Martin.
But with all the talk of a return to the Moon or an asteroid sortie as a potential precursor to a Mars mission, a confirmed goal or destination is lacking. Gerstenmaier described this as “capability rather than destination-driven exploration”, admitting that current Nasa goals and strategies “are only generic”.
So, with its space shuttles being decommissioned and decontaminated in preparation for display in American museums, Nasa’s manned spaceflight programme stands at a crossroads, apparently unsure whether to turn to commercial providers or back towards its standard government-industry contracting system. The only certainty is that Nasa would prefer not to rely on Russia to transport American crews.
But space exploration is no longer bipolar, and international cooperation has dominated manned spaceflight, most notably with the ISS, for many years. Indeed, according to ESA director general Jean-Jacques Dordain, the 50 years of manned spaceflight that began with Yuri Gagarin in 1961 can be characterised as “eight years of competition and 42 years of cooperation”.
In fact, half the pressurised volume of the ISS is provided by modules made in Turin by Thales-Alenia Space (TAS), and ESA contributes to cargo delivery using its Automated Transfer Vehicle (ATV).
Interestingly, TAS wants to extend this cooperation to the MPCV capsule. As explained by Maria Stella Lavitola, director of marketing and sales for space infrastructure, “the ATV offsets the costs of the ISS for Europe, and we are thinking about new developments based on ATV”. According to Lavitola, Thales is talking to Nasa about the possibility of providing the service module for Lockheed Martin’s MPCV based on an upgraded ATV. “It could be a good deal for Nasa [in terms of offsets]”, she said, “even though Lockheed Martin won’t be happy about it”. The formal decision to make this an official ESA contribution will be taken at the next ESA Ministerial Council in 2012.
One encouraging sign among all the uncertainty following the Shuttle’s demise is that, thankfully, engineering lessons have been learned in 30 years of Shuttle operations. Using the vehicle’s computers, main engines and thermal protection system as examples, Space Shuttle programme manager John Shannon summarised this as developing a culture to “test to the boundaries of capability, document discrepancies and don’t stop improving”.
For one thing, Shannon said, it takes time for a system to mature; equally importantly, you need to keep the team of specialists together for the duration of the programme, in part because different systems mature differently. “Software ages like wine”, he commented, “but hardware ages like milk”.
In answer to detractors who question the reliability of the nascent commercial providers, Shannon opined that SpaceX and Orbital were adopting the culture by “testing into the corners of the box”. This hasn’t dissuaded former Apollo astronauts Neil Armstrong and Gene Cernan from telling Congress that the Shuttle should be returned to flight. “Get the Shuttle out of the garage,” demanded Cernan. “It’s in its prime.”
As a result of “lessons learned”, the Shuttle’s 135th mission may well have been its safest and most reliable, but nonetheless its time has surely passed. In fact, if it flies in space again, I’ll eat my treasured piece of thermal tile.
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