Much has been made of the impending gap in U.S. human spaceflight capabilities when NASA retires its space shuttle fleet next year in the absence of an operational follow-on program. But ferrying people to and from the international space station is not the only capability at risk in the coming years: Development of commercial vehicles for delivering cargo to the orbital outpost also is behind schedule.

Orbital Sciences Corp. and Space Exploration Technologies Corp. (SpaceX) are developing space station logistics vehicles under NASA’s Commercial Orbital Transportation Services (COTS) program and are under contract to begin resupplying the outpost within the next year. SpaceX’s $1.6 billion Commercial Resupply Services (CRS) contract calls for logistics flights to begin this December, but the company will not be ready before late next year, says Michael Suffredini, space station program manager at NASA’s Johnson Space Center in Houston. Orbital’s $1.9 billion contract calls for services to begin next October, but the company says an early 2012 date is now anticipated.

Suffredini is hopeful Congress will approve by year’s end funding needed for an additional space shuttle mission in June that was authorized in recently enacted NASA legislation. The extra flight would allow NASA to stock up on spares and other cargo aboard the station while giving Orbital and SpaceX more breathing room. NASA has other cargo delivery options, including Europe’s Automated Transfer Vehicle, Japan’s H-2 Transfer Vehicle and Russia’s Progress capsule.

Suffredini spoke recently with Space News staff writer Amy Svitak.


At what point do delays to the CRS capabilities become a real problem for the space station program?

We have the SpaceX Demo 1 that’s coming up in December. We have Demo 2 next summer and, under the current plan, Demo 3 in the summertime. So that means that the first SpaceX CRS flight is probably in the late fall timeframe, give or take. And Orbital is working on having its first orbital [demo] flight also in the fall of 2011. If they fly roughly on those dates — which are dates that have slipped to the right relative to the original dates that we signed contracts for, but are not unreasonable given that they’re new developments — then as a program we’ll be fine.


What’s the point at which you begin to have problems?

Today we’re six to nine months delayed from the original dates. If we slip a year from the original dates we’ll be fine. I’m not particularly worried about that. If we slip two years from the original dates and our international partners keep their vehicles on schedule, we’ll probably be able to make it to the end of that period and still be OK. But what if the H-2 Transfer Vehicle moves to the right, or the Automated Transfer Vehicle moves to the right, or God forbid they don’t make it to orbit? When you start looking at that in combination with the commercial guys, then you start to have problems sending up cargo to six crew members on station.


How critical to your planning is the additional space shuttle mission approved in the NASA Authorization Act of 2010?

We’ve promoted the idea of having this shuttle flight in the June timeframe, and we’re trying to put enough logistics on to get us through the end of 2012, in the event that the CRS flights are delayed as much as two years and to protect ourselves from any other things that could happen with the existing vehicles.

Today the first SpaceX CRS mission is in the summertime, and [SpaceX founder and Chief Executive Elon Musk] gets upset if we speculate too much, but I’m going to expect to see that first SpaceX CRS mission, assuming no major anomalies, in the fall of 2011. We’ve slipped seven to nine months. That’s not great, but you can expect in a new development that you’re going to have challenges. These guys had a very aggressive schedule, so in my mind I’ve always kind of assumed they’d be challenged and I’ve always been promoting the idea that we ought to have one more shuttle flight to make sure we’ve put enough logistics on the station to keep things whole.


The schedule you’ve outlined calls for SpaceX to complete four increasingly complex missions — two that berth with station — in less than a year. Is this realistic?

I think that will be challenging, absolutely. Now one of the things they’ve talked to us about is combining the second and third demo. We’ve suggested we let them fly the first demo, and then we’ll go review their verification steps and testing on the ground to see if we could get comfortable with the second flight actually coming all the way to the station.


When does NASA need firm word on whether another shuttle flight will be funded?

We need to get the teams turned on, and we need to make sure they stay staffed right. Right after STS-134 (scheduled for late February), you can imagine the team is going to start down-staffing. If you’re going to cut down on staff, we need to tell the companies about a month before that so we can get all the paperwork done for those notices. So we’re shooting for the end of December to make sure we don’t perturbate the work force.


Are there space station supplies for which there is no delivery alternative to the shuttle?

Well, one thing that is certainly unique to shuttle that we plan to take advantage of on STS-135 is the return of the pump module that failed. I have no other way to bring external orbital replacement units home. We went to a build-and-burn philosophy and we accepted that risk, but now that it’s failed a little early, we can’t really determine whether it was a mechanical or electrical failure. We’d really like to get that home and do failure analysis on it. That’s the one thing I cannot do with the other vehicles. Assuming the other vehicles fly roughly close to the schedule that we talked about, I can put all those same logistics on those vehicles as well. The question we’re asking ourselves is if the CRS vehicles slip up to two years, then we’re relying on the Automated Transfer Vehicle and the H-2A Transfer Vehicle and we’re flying only about one of those per year. And if you lose, for whatever reason, either one of those, you’re really at a point where you’re going to have to make a decision to staff down to three people at the station.


What backup capabilities can Russian-built vehicles offer?

Progress can carry up dry cargo, water and propellant. The problem is it can’t take up external orbital replacement units and it can’t return, so all the return we would have to do would be on Soyuz, which would mean research, primarily, would have to take a hit. And now you’re just talking about how quickly can the Russians staff up to build Progresses. They’re already flying about five Progresses a year. They’re building and flying four Soyuz capsules a year. So they are really, really busy. And they need two years from the time we tell them we need a Progress to the time they can fly a Progress. Another thing is that their range is extremely busy out there at Baikonur Cosmodrome in Kazakhstan. That doesn’t give you much margin. So, depending on when you had your failure, you could potentially be in a position where you’re going to have to downsize the crew just to get through that lean period before you staff back up.


Are you concerned that the post-shuttle vehicles in the pipeline are too small to meet cargo needs for station?

Once they are flying on a regular basis, smaller logistics vehicles are not necessarily a bad thing; having multiple smaller vehicles for normal logistics-type work is probably better, because if you get smaller vehicles flying more often then you don’t have to keep quite as much hardware onboard space station and you have some dissimilar redundancy in case any one of them has a problem. But getting there is a challenge. That’s why we worry about this period from shuttle retirement to when these guys have actually flown and docked to the station, transferred two orbital replacement units and returned home and shown that their systems worked.


Do you see CRS hardware in the pipeline at Orbital and SpaceX?

They’re building their hardware. The schedules that are on paper today are challenged based on where we know they are in terms of seeing the hardware and seeing the infrastructure they’re putting in place. Orbital has processing facilities they have to build. SpaceX is a little further along in that regard. Neither company has this long line of rockets and capsules ready to go fly. In some cases they haven’t even taken delivery of the vehicle that’s going to go on their first demo flight to the station. So in that regard, they’ve got a ways to go, but we know based on their manufacturing and the different places we see and the work we’re doing on verifications that they are moving ahead and they’re making progress. But that also lets us know that the dates are probably not the final slip to the right.