The 2017 NASA astronaut class on stage at the Johnson Space Center for their debut in June. (credit: NASA/Bill Ingalls) The last astronaut class?

The recent unveiling of NASA’s newest astronaut class got an unusual amount of attention: a ceremony at the Johnson Space Center, an appearance by the vice president, and lots of media coverage. In the past, astronaut class announcements got far less fanfare, with a press release and maybe a press conference at some point. Last month’s ceremonies were reminiscent of the original Mercury Seven, or maybe the 1978 class with the first women and minority astronaut candidates. It’s possible that this class got so much fanfare in part because it’s the last astronaut class NASA will need to select likely for years. So why did it get so much attention? NASA might argue it was because of the unprecedented interest in becoming an astronaut, with more than 18,000 people submitting applications. Despite all the complaints about a lack of activity in NASA’s human spaceflight program, a lot of people want to participate in human spaceflight. The problem is that they won’t get that many opportunities to do so. It’s possible that this class got so much fanfare in part because it’s the last astronaut class NASA will need to select likely for years. With the shuttle era now firmly behind us, the giant astronaut corps of that era, when a few dozen people a year might get to fly on shuttle missions, is no longer needed. The corps is shrinking, but there’s still a lot more qualified people than flight opportunities available. Right now, NASA is flying, on average, only four of its astronauts a year to space, on six-month increments accounting for two of the three crew slots on the US Operating Segment (USOS) of the station. (The third slot goes to an astronaut from Europe, Japan, or Canada.) Four a year is not many: a single shuttle mission would typically fly even more, and there would be several shuttle missions a year. The good news is that this number will grow—just not by much. NASA is taking advantage of a temporary decrease in the size of the Russian crew from three to two to fly another NASA astronaut, starting later this year. Russia will eventually get that slot back, whenever its long-delayed Nauka lab module finally launches (maybe next year?) However, NASA said that, once commercial crew vehicles start flying (maybe 2019?) they will add a fourth USOS slot, presumably for a NASA astronaut, increasing the station’s overall crew size to seven. There will also be a few one-off short-term missions for NASA astronauts, flying the Boeing and SpaceX crew demo missions to the ISS. Boeing says they plan to fly one NASA astronaut along with a Boeing test pilot—which everyone presumes to be former astronaut Chris Ferguson—while SpaceX will fly two NASA astronauts. NASA selected a “cadre” of four astronauts to train for those missions, so three of them will presumably fly sometime in 2018 (maybe?) Then there are NASA “exploration” missions, which will be flights of the Orion spacecraft. NASA says they’re still on track for a 2021 flight of the first crewed Orion mission, EM-2, but their track record doesn’t give people much confidence in that schedule. Let’s give them the benefit of the doubt, at least partially, and assume a 2022 launch of EM-2. NASA then plans to fly Orion missions once a year thereafter, at least through the end of the decade. Those will likely be short-term missions for the most part, perhaps building up to longer missions later in the decade assuming NASA does construct its proposed Deep Space Gateway and even a Deep Space Transport spacecraft that will fly around cislunar space doing… something in the late 2020s. NASA hasn’t said much about crews for those missions, but it’s reasonable to assume that each mission will carry no more than four astronauts. It’s likely at least one seat will go to an international partner, like ESA, which is building the Orion service module. So that gives us six astronaut slots a year to the ISS, plus the three commercial crew demo flights, and then three astronaut slots a year starting in 2022 on Orion flights. Right now the international partners have committed to the ISS through only 2024, but it seems increasingly likely at this point that they’ll extend it to 2028. Thus, from 2018 through 2029, that gives us about 93 astronaut mission slots that will need to be filled. (A few have already been filled, of course, with the commercial crew demo flights and some ISS crew assignments for 2018.) That’s not a lot, at least compared to the shuttle era. Just one of the eight people in the 2013 class has been selected for a flight. Given that track record, some of the members of the class of 2017 probably won’t get their first flights until the mid-2020s. So much for the demand for astronauts. Now for the supply. NASA, on its website, lists 43 active astronauts. That doesn’t include the 12 new astronauts announced last month, since they still have to go through two years of training before they’re eligible for assignments. By mid-2019, there could be as many as 55 active astronauts, although a few will likely retire over the next two years. Those 43 active astronauts—which excludes those in management positions and thus not eligible for flights—have combined flown, or are assigned to fly, about 75 missions. Some are experienced, with three or more missions, especially those who flew only on the shuttle. But some of the members of the 2009 astronaut class have only recently gotten assignments for their first flights, and just one of the eight people in the 2013 class has been selected for a flight. Given that track record, some of the members of the class of 2017 probably won’t get their first flights until the mid-2020s. Of course, it would go faster if astronauts were one-and-done, but that’s unlikely in most cases given both the desire of the astronauts themselves to fly again, as well as NASA’s desire to get the most out of the investment they’re making selecting and training these people. A few might leave after a single flight, but it’s reasonable to assume that most will stay for at least two, and maybe three, missions each. If we assume the average astronaut flies three missions, that means the current corps, plus the 12 new members, could fill about 90 slots, given the previous and assigned flights for current astronauts. That’s very close to the number of available slots for ISS and exploration missions through the 2020s! In other words, NASA’s current astronaut corps is sufficient to meet the agency’s needs for more than a decade. Certainly that might be stretching it. Some astronauts will leave early, and three long-duration missions per astronaut might be too much (although in some cases that third mission might instead be a shorter Orion flight.) There’s also, sadly, the prospect of accidents along the way. Nonetheless, what that suggests is that NASA probably won’t be in much of a hurry to hire another class of astronauts. NASA has recently been bringing in new classes every four years—the previous two classes were in 2013 and 2009—but it’s not clear there will be much demand for new astronauts in 2021. NASA could select a few in four years, but there’s a good chance none of them would fly before a 2028 retirement of the ISS. So, NASA will probably stretch out the selection of the next class by a few years, or hire only a few in 2021. That’s not good news to the nearly 18,000 not selected in this round, or even the 120 that made the cut for interviews and medical exams. In the past, if you made it that far, there was a decent chance you’d make it if you applied again (or again and again), getting closer with each attempt. Now, there’s not too many opportunities for second chances. There are some things that could be done to increase flight opportunities, at least to a modest degree. One would be to move from six-month crew rotations on the ISS to perhaps four months, something suggested by former chief astronaut Chris Cassidy (see “Selecting a new astronaut class”, The Space Review, June 19, 2017). That would increase the number of ISS crew slots a year by 50 percent, from six to nine: not a lot, but every little bit helps. It would come at the expense of more commercial crew missions, though, to swap out crews. But, by the time NASA gets serious about selecting astronaut classes later in the 2020s for missions to Mars, what it means to be an astronaut will also be changing. Also, at some point in the 2020s, there will be commercial modules on the ISS, and later commercial space stations. The former could allow for increased crews, which could mean more slots for NASA astronauts depending on the arrangements. The latter could also give opportunities for NASA astronauts to fly independent from the ISS. NASA leadership has stated in the past that they expect a need for low Earth orbit research even after the end of the ISS, so flying a few NASA astronauts a year to a Bigelow or Axiom space station is not out of the question. But, by the time NASA gets serious about selecting astronaut classes later in the 2020s for missions to Mars (assuming, perhaps too optimistically, that NASA will stay on something like its current plans), what it means to be an astronaut will also be changing. By then more “non-professional” astronauts will be flying in space, be they scientists or technicians working on those commercial space stations, or maybe tourists just there to enjoy the view. Being an “astronaut” runs the risk of losing some cachet. At the very least, they may offer easier paths to get to space than through NASA. So, contrary to the headline of this essay, this class of astronauts won’t be the last NASA selects. It will be, though, the last it selects for several years, and probably the largest it selects for many more years to some. Future astronaut selections may not have the same level of fanfare as this one—and maybe, as spaceflight becomes a little more common, that’s not a bad thing. Home









