Rumors are circulating on Twitter that NASA is shaking up its schedule for the Space Launch System. According to the scuttlebutt, the rocket's maiden launch may carry astronauts onboard. Popular Science has confirmed with Stuart McClung, an engineer on the Orion capsule that's designed to ride on SLS, that NASA is indeed considering these changes.
Until now, the plan was that SLS would take off on its inaugural flight (Exploration Mission 1, or EM-1) in 2018, carrying an empty Orion capsule. Astronauts wouldn't ride on SLS until approximately 2021, when the rocket would launch the crewed Orion capsule into lunar orbit.
McClung confirmed that Robert Lightfoot, NASA's acting administrator, sent out an email to NASA employees announcing that he has asked for a study to evaluate the feasibility of adding crew to EM-1. "The message notes that the extra work would require a different launch date," says McClung.
The capsule that was originally constructed for the SLS's maiden launch doesn't carry all the safety systems that would be used for a crewed voyage, "so we'd have to augment it with some crew provisions that are not in the current plan," says McClung. Modifying it to keep a crew safe would take some time—hence, the potential delay.
Flying humans on the first launch of a rocket is somewhat nontraditional. NASA's first human spaceflight programs, including Mercury, Gemini, and Apollo, all utilized uncrewed test flights before humans flew onboard. Today's private spaceflight companies are also taking this cautious approach. We are, after all, talking about strapping humans to a meticulously-constructed explosive device. But the space shuttle flew without an uncrewed test flight beforehand, without any immediate disaster.
The Aerospace Safety Advisory Panel ("ASAP," referenced in the tweet above), which advises NASA on safety and performance, may not love the idea. But then again, they haven't been 100 percent thrilled about SLS to begin with.
For its part, the Orion capsule design has already proven its spaceworthiness in uncrewed test flights.
The change of plan may combat the somewhat lackluster enthusiasm for the Asteroid Redirect Mission, which is supposed to carry an asteroid into lunar orbit for the first SLS crew to visit in the 2020s.
Personally, McClung says he's excited about the possibility of launching astronauts onboard EM-1. "I like the idea of the challenge."