Archive for February, 2008

Wrong Way Round

February 29, 2008

I’ve just noticed something odd about the configuration of the Earth Departure Stage (EDS) and Orion, with the Lunar Surface Access Module (LSAM – which I’m now reading is to be called Altair).

After Earth Orbital Rendezvous the stack will then depart for the Moon, with the EDS (effectively the Ares V 3rd stage) providing the thrust. It’s just that the thrust is the wrong way. The astronauts will be accelerating in the opposite direction to that in which they left Earth. They will accelerate in the -x direction, rather than +x. The cone of the CEV will be accelerating blunt end first rather than sharp end first as they will for the other main acceleration phases of any mission, including transEarth injection (TEI) and reentry/landing.

I can imagine astronauts basically suspended in their harnesses as the up they were familiar with on take off becomes down. I can’t imagine it is easy to design couches that are reversible in this way.
This just doesn’t seem right. The acceleration of the EDS stack must be significant, and will be several minutes in length if it is anything like Apollo/Saturn. You’ll recall that the Apollo/Saturn TLI stack, with the SIVB pushing it, was in the same +x axis as at launch, TEI and reentry. How will astronauts cope?

So, have I just ruined a whole vehicle development programme, or am I missing something, or is the problem just not as serious as I think it must be?


February 2, 2008

Constellation logo

I’ve been reading a bit about the Constellation Program, the suite of boosters and spacecraft NASA are currently developing to replace the shuttle, return to the Moon and go on to Mars. I’ve been keeping an eye on developments, but haven’t even trawled through all Wikipedia has to offer. It’s nice to see books appear, just like they did for Apollo, which summarise the craft being developed. I shall be interested to see how quaint they, like the Apollo material, look when we see the real thing.

I wonder if Constellation/Orion will capture the imagination like Saturn/Apollo? Is it just that Apollo is no more that it seems more romantic? Is it a love of something lost, a kind of nostalgia? Or is it that we know, in our world of mp3 players, mobile phones, pocket calculators forgoodnesssake that it all seems so amazingly primitive.

Remember the first ‘mobile’ phones? The ones you kept in the car. The ones that, if you wanted to walk with it you had to unplug from the car and carry a briefcase with the battery? Sophisticated weren’t they? That was what, 15 years or so after Gene Cernan stepped off the Moon! But the laws of physics, as NASA engineers are fond of saying (or was it Scotty?) haven’t changed. Electronics can help streamline and automate systems, but massive boosters are still needed (the Ares V, for example, is likely to be nearly as tall and more powerful than Saturn V).

I think the main challenges of any travel outside low Earth orbit are likely to be physiological and psychological. We’re planning to go back to the Moon to spend weeks and months at a time there. A Mars mission is going to take years. Crew will be isolated (in communication time as well as in space) from all but a very few others. The toll of weightlessness or 1/6 gravity is known to be significant, and medical emergencies are inevitable but unthinkable. Space will be limited (ironically, I suppose).

So, will crew members on a 6 month cruise to Mars, and during their 2 year stay there be given holiday? How would that work? Or will they be kept busy every day for 3 years? How will they get away from it all?

The astronauts of the future really will have to have the Right Stuff.