Thoughts on NASA and the near future of space exploration

I posted the following reply in the NASA discussion group on LinkedIn. The original post was soliciting thoughts on the changes in priorities for NASA in response to the president's budget request.

The Constellation program was canceled because this administration was unwilling to continue investing many billions of dollars a year to develop a whole new launch capability that would not be ready for 7 to 10 years. For this investment, we would get two new rockets that would never have a very high flight rate, and thus would be extremely expensive to operate. That high cost of development was literally starving many innovative science and engineering efforts currently underway, or planned for the near future. The high cost of operations would mean that this situation would continue into the indefinite future. This was a bargain that this administration was no longer willing to make... not when there appeared to be a viable alternative.

This alternative has just as much of a chance of success as the Constellation program, but also requires much less investment and has the potential to offer much greater capacity and redundancy to the US spaceflight capability. NASA is getting a net increase in budget, and the freedom to spend it on actual innovative research and development projects. Some of this research will vastly improve our ability to carry out long duration spaceflight missions, while other research would dramatically improve our understanding of the Earth, and our environment.

As for science on the ISS: The president's budget actually extends the life of the station until at least 2020 - further improving the chances of doing useful science on the station. The SpaceX Dragon capsule is being designed to provide a significant amount of down mass capability for the ISS. Although the Cygnus transport will not initially be able to support this capability, Orbital has made some encouraging remarks regarding their plans to upgrade the Cygnus craft to have reentry capabilities. The ESA has also made similar comments about their ATV modules.

I agree that our backs are up against the wall with regards to the ability of the US to independently access space. But perhaps this sense of urgency will prompt more commercial providers to finally step up to the plate and start investing their own resources in developing this domestic capability - with an appropriate amount of assistance and investment from NASA. However, at the same time, NASA has to back off a little bit and let them develop these systems to the best of their abilities.

No one is suggesting that we immediately start putting astronauts on these new vehicles. (Not like they did for Mercury, Gemini, Apollo, and Shuttle, and what they were planning on doing for Orion.) From what I've heard, each new entrant and each new system will have to be proven out over a number of unmanned test flights and/or cargo flights before NASA will consider using them for human transport. This seems both fair and prudent.

Will it be dangerous? Yes. Will their be risk? Yes, of course. There always has been and their always will be. However, if it's an endeavor worth pursuing, then you do you best to mitigate the risk and to plan for all of the contingencies that you can imagine. In the end, though, you have to accept the whatever risks remain and just fly the vehicles that you have.

There will be failures, but we will learn from them. There will be deaths, but not by anyone who wasn't fully aware of the risks. They will choose to go, and when they fall, there will still be others lined up waiting to go. For them, it will be the chance to pursue a dream, and the opportunity to push back the boundaries of science and exploration. If you build it, they will most certainly come.

The ISS as fuel depot testbed

I've been wondering for some time if the ISS could be used to advance the technology required to perfect propellant depot technology. It seems that nearly all of the required hardware is already on board the station. The current ECLSS on the ISS electrolyze waste water and condensate to generate breathable oxygen, with the excess hydrogen being vented to space. If the hydrogen stream could be diverted into a Sabatier reactor, then CO₂ could be scrubbed from the atmosphere and turned into methane fuel.

I've also been wondering for if a propellant depot infrastructure should be resupplied with pure water rather than the cryogenic fluids. The favorable density and handling properties of water as opposed to LO2/LH2 would appear to make it the better choice for transporting aboard a very simple tanker over potentially long time periods. When shipped as water, the "fuel" can be transported in a non-cryogenic, inert state, and then once delivered to the depot, it can be cracked into O2/H2, liquefied, and stored until it is needed.

Of course, this assumes that your depot has sufficient power and/or time to split water and keep the fuel properly chilled. I found this page which describes the Russian Elektron unit. This article cites a passage from a NASA training manual:

NASA TRAINING MANUAL ON ‘ELEKTRON’

From the “NASA Familiarization Manual on Russian Segment Crew Systems”, Published in 1997.

3.1. Oxygen Supply System
...
The decomposition of 1 kg (2.2 lbs) of water yields 25 L (0.88 ft3) of oxygen per hour at a pressure of 760 mmHg, which is enough to support one crew member for one day. To provide the daily amount of oxygen for 3 - 4 crew members, 3 - 4 kg (6.6 - 8.8 lbs) of water must be decomposed. Power consumption of the process is ~ 1 kW.

A kilogram per hour at one kW, seems like a very reasonable rate, at that's just for one Elektron unit (if I'm reading this correctly). If necessary, this can scaled up with additional units if sufficient power is available. It may be possible to build even more power efficient electrolysis system if the work of Dr. Nocera at MIT can be turned into a practical device that will operate in zero-G conditions.

If the depot is also crewed, then a steady supply of water would be required any way. The crewed depot could also generate methane as an additional propellant option if the ECLSS included a Sabatier reactor as well as an electrolysis unit. With the exception of the Sabatier reactor and some cryogenic storage tanks, the ISS already possesses all of the hardware. The existing U.S. electrolysis units even have hardware available for connecting to a Sabatier reactor.

So, what would be the point of having the ISS generate and store propellant? Well, first of all, it is currently our only manned research outpost in zero-G. It would therefore be expedient to take advantage of these facilities to work out the basics of cryogenic fluid transfer in micro-gravity. The data obtained from ISS experiments could go along way towards reducing the techological risks associated with propellant depot development.

The ISS also needs fuel for station-keeping. Having the ability to generate it's own propellant would be a nice capability to have. This would also simplify the ISS resupply requirements. Rather than having to deliver water and propellant, each in the individual compartments, only water would be required. The water tanks could be made larger, and therefore more mass efficient. Since propellants would no longer need to be transported (I think hypergolics are currently used), the handling of the payload for resupply missions would be much less hazardous.

Finally, with the ability to produce fuel, the ISS could support a small array of space tugs and transfer vehicles which would service the station and other objects in nearby orbits. For example, imagine that SpaceX puts up a couple of Dragon lab modules in orbits which are coplanar with the ISS. Now imagine that the ISS has a slightly modified ATV docked to it. It might then be possible for an ISS astronaut to use the ATV to rendezvous with the Dragon module and perform any necessary maintenance or repairs.

I have some additional thoughts on how to convert the ATV into a crewed orbital transfer vehicle, but I think I'll save those for another post.

Dragon as the new CRV?

In my previous post (A more gentle transition) I tossed out an idea that perhaps a Dragon capsule, launched to the station in support of ISS logistics, could be modified to serve as a crew lifeboat while it is docked to the station. I was quite surprised, then, to stumble across this post (The new X-38/CRV: SpaceX's Dragon?) by Rob Coppinger yesterday, which references this article (Race to the International Space Station begins in earnest) by John Croft over at Flight Global.

I had no idea if such a thing was possible; only that it would make sense to try and use the Dragon for ISS crew-return if dealing with the Russians proved to be problematic in the future. Using the Dragon this way would also remove one of the frequently cited reasons why the Shuttle should not be used to service the ISS beyond 2010; namely that it could not remain docked to the ISS for extended periods of time, and thus could not be used as an ISS lifeboat. But if this story is correct, then there are already studies underway to validate this concept.

The primary difference between this report and my hypothetical scenario is that they appear to be studying the prospect of delivering the Dragon capsule in the payload bay of the Space Shuttle. I guess I assumed that the Falcon 9 would have successfully flown by the time this would be needed. I cannot think of any other reason why they would rather use the Shuttle. If Falcon 9 has been successfully flown by 2010, then it would certainly be cheaper to launch the capsule to the station using a Falcon 9; not to mention the fact that the Dragon is designed to be launched by a Falcon 9.

My other assumption regarding how it might be easy to temporarily convert a cargo Dragon into a CRV while it is docked to the station, may have also been a little too optimistic. There are probably alot of sub-systems that would be present in a crewed Dragon (even a minimal reentry version), that would probably not be found on an unmanned cargo Dragon. If absolutely necessary, a crew could probably ride down like cargo; however, they would most likely want a more robust life-support capacity and manual flight controls available in an actual CRV Dragon.

I have just one more idea, that I'd like to throw out there. I've been thinking for some time now that NASA should get a Sundancer class module from Bigelow and launch it into an orbit near the Hubble space telescope. That way, if anything goes wrong with the STS-125 mission, they would at least have the opportunity to use the module as a safe haven until a rescue mission can be mounted.

Now, there may be another way to add crew rescue capability to STS-125. If they are actually studying the feasibility of launching the Dragon on the Shuttle, then perhaps it would be possible to tuck one away in the back of the payload bay for the Hubble repair mission. Would there be room? Would the Dragon be ready in time? My guess is: probably not, but it's an interesting idea none-the-less.

A more gentle transition

There has been much gnashing of teeth concerning the imminent, and all but inevitable, gap in American manned spaceflight capability after the Shuttles are mothballed in 2010. I've been thinking about this problem, off and on, for some time now. Given the current state of NASA and the commercial space transportation industry, there are really only a couple of realistic options for dealing with "the Gap".

The first option is for NASA to continue flying the shuttle a couple of times a year beyond 2010 until a suitable replacement is available. I have never really had a problem with flying the Shuttle past 2010. It will be just as dangerous to fly it then as it is now (and yes, I would jump at the chance to fly in it if it were offered to me). Many have dismissed the possibility of extending the Shuttle service on the grounds that: a) it's too expensive and would consume resources that NASA would rather be devoting to Ares I/Orion, and b) it wouldn't solve the underlying problem of how to get our own astronauts to and from the space station without having to rely on the Soyuz capsules as lifeboats.

In my own opinion, I think that using the Shuttle strictly for crew-rotation and logistics deliveries is a terrible waste of the Shuttle's unique capabilities. Instead, I'd like to see NASA take advantage of these extra flight opportunities to continue expanding the ISS beyond the minimal 'US core complete' configuration. Many additional modules have been, or are nearly, completed. The Shuttle was conceived, designed and built to support the construction of a Space Station. So long as the Shuttle is still active, it should be doing what it does best.

Another possibility for reducing 'the Gap' is for NASA to provide additional resources to companies like SpaceX to assist with the rapid development of launch vehicles suitable for manned spaceflight. For a very small fraction of the resources currently being poured into the Ares/Orion development, SpaceX could potentially have the Falcon 9 rocket and the Dragon capsule ready two to three years before the first Orion capsules would be available.

There may other options which have some chance of mitigating the consequences of retiring the Shuttle before its successor comes online, but for now, I'd like to explore a third option that lies somewhere in between the two options mentioned above.

Let's assume that SpaceX will be able to demonstrate reliable cargo delivery to the station and safe return to the Earth with the Dragon capsule by the end of 2010 or early 2011. At that point, the main thing preventing crew rotation using the Dragon is the development and demonstration of safe and reliable crew launch on the Falcon 9. Elon Musk has stated that SpaceX could have crewed Dragon ready within three years if they were to be funded under the COTS-D program (perhaps a couple more years if no COTS-D funding were provided). That's most likely an optimistic estimate, but even still, that means no crew launch capability until at least the 2012-2013 time frame.

Let's imagine then that NASA is persuaded by Congress to continue flying the space shuttle to the station twice a year until a suitable replacement vehicle is ready. By that time the Dragon will likely have demonstrated the ability to stay on orbit at the station for months at a time and then execute a safe and controlled reentry. With probably very few modifications, it should be possible to convert the Dragon capsule into a crew life boat once it has delivered its cargo to the station. That's a lifeboat that can seat seven (i.e. the entire ISS crew complement with room to spare).

So long as no problems arise, the crews can be rotated in and out on the shuttle. The Dragon could continue to be used to de-orbit important cargo, but in the event of a emergency situation, it could also be used to return all or just part of the crew. Assuming the Russians still have at least one Soyuz docked to the station, the redundant life-boat capability would mean that the station would not necessarily have to be abandoned if only one or two of the crew needed to be immediately returned to Earth.

So, rather than saying either Dragon or the Shuttle, why not say both. We can make the most out of the Shuttles' extension to really finish building out the ISS. At the same time, the Dragon can be fulfilling a useful role as a lifeboat for the expanded crew without having to rely on the availability of additional Soyuz capsules. When the Falcon 9 / Dragon capsule has been qualified for manned launches, then crew rotations can be transitioned from the Shuttle to the Dragon, and the Shuttles can finally be retired for good.

Dragon, you are up.

Most of you reading this probably already have heard about the remarks made by Senator Bill Nelson to the Orlando Sentinel (link) concerning the recent actions taken by Russia in South Ossetia and how it will negatively impact the current negotiations for purchasing Soyuz flights beyond 2011. From what I've read in the mainstream media, they have pretty much taken the Senator's statement to mean that we will be effectively cut off from the ISS after the shuttle is retired until Ares/Orion is ready to fly. However, there is an alternative that they seem to be overlooking.

For over a year now, NASA (and Congress) have been avoiding making a decision on whether or not to provide funding for the COTS-D option. With these latest developments, it seems as though Plan A (continue purchasing Soyuz flights ad nauseum) may no longer be politically feasible. That means that Plan B (development of the crewed SpaceX Dragon capsule) may now start getting some serious support, and resources, thrown its way.

There have been some in the mainstream media who have not looked favorably upon SpaceX after its recent third failure to launch the Falcon I rocket. Some doubt that SpaceX will be able to meet its existing COTS commitments, let alone be able to provide crewed launch capability. As one person commented, "If they can't launch the little one, how do they expect to launch the big one?"

The primary purpose of the "little one" is for rigorously testing, debugging, and characterizing the performance of the very same systems that will eventually fly on the "big one". This is a very sound strategy, and once the Falcon I has successfully shaken out all of the bugs in its systems, I would be very surprised if any of the first flights of the Falcon IX vehicle fail to make it into orbit. The design of the Falcon IX vehicle is more robust than that of the Falcon I, and as such it is much more likely to be able to compensate for any remaining small glitches which may crop up and still succeed in its mission.

Elon Musk has stated on several occasions that SpaceX can close the gap in US access to the ISS. Well, now may be the perfect opportunity for him to get the support he needs to complete work on the crewed Dragon and have it on the pad by 2011. Although I suspect that work on the Dragon capsule has been progressing towards crewed capability regardless of whether or not NASA comes through with the COTS-D funds, additional political and financial support would certainly help things along.

The Ares I/Orion was never going to be able to close the gap in US access to the ISS. NASA has been willing to rely on the "devil they know" with access via Russia's Soyuz capsules, but that may no longer be possible. It now seems like the Dragon capsule may be our best hope (our only hope) for uninterrupted access to the ISS.

Dragon, you're up. Let's see what you can do.