Thursday, February 14, 2008

Giving Up On Steroids

Poor Roger "the Rocket" Clemens. You could almost see him shrinking on the stand yesterday as he proclaimed his innocence. Whether you believe he did it or not, we have now been educated in the dangers inherent in trying to bulk yourself into something you shouldn't be.

The Emperor's self-proclaimed,"Apollo on steroids" is facing the same fate. We've discussed many times here how overweight ORION is, at 5m diameter and six crew to ISS, exceeding the capability of the ill-formed ARES I rocket to lift it. Now it seems that the minions have run out of design tricks to get the weight back in the box. All but one, that is, and they are studying this one hard.

The CEV contractor has been asked to quietly address the weight issue by reducing the crew size to four for trips to the ISS and see how that helps. That appears to be the only way the capsule will limbo under the wire. And the implications are just as astounding.

Four crew to ISS means a CEV and a Soyuz would always have to be docked to bring six crew back in the event of an emergency evacuation. Alternately, the permanent crew size on ISS might have to be reduced to four. So instead of a full complement of Americans onboard, perhaps just one with the car keys is all that we can afford?

The much smaller Apollo was once configured to carry five astronauts back from Skylab in the event of a primary taxi failure. Now the Emperor's folly, steroids and all, appears unlikely to achieve that very level of performance.


Ray said...

Questions/comments from a non-engineer, non-NASA observer:

Why go to 4 crew to ISS? It seems at my first naive glance that giving up on the steroids is a good idea, but that 3 would be a more sensible number, since 2 of those (or 1 with 1 Russian) add up to the full ISS crew size. Maybe going to 3 instead of 4 would allow some additional engineering trades that would improve safety, reduce development or operational cost, or reduce schedule.

Would the smaller CEV fit on an EELV or Falcon with NASA human-ratings requirements? If so, that would remove one of my objections to Ares 1/Orion. It would allow multiple launchers, commercial or NASA, for Orion, which would give fault tolerance to the architecture in case of trouble with 1 launcher. It would also allow some Orion launches to have commercial usefulness (help new commercial launchers or help spread EELV costs).

With the smaller CEV, what are the implications to the lunar mission crew size? Again, would existing or planned non-Ares launchers be able to fill that role, allowing Ares 1 to just be a backup for those systems and a development program for Ares V?

What are the down sides of having 2 escape systems attached to the ISS?

Rocket Man said...

Don't go looking too closely for logic in these decisions. Why would the government spend so many billions of dollars and only re-create the same capability as Apollo? That question would be asked resoundingly by Congress if 3 were the answer. Hence, 4.

The government doesn't want to attack the real problem, which is that it has the wrong architecture.

Discussing CEV involves many complicated issues. A lot of the design was mandated up front, instead of letting the mission requirements drive out the architecture and the allocations naturally.

So it's not just about making it smaller, diameter-wise. It's about taking out requirements which are adding multiplicative weight (more crew, more consumables, more structure to support the stuff all multiplies together). Examples of things that could help include limiting the size (height) of crew, eliminating galleys and toilets and private areas, etc.

CEV should have been sized to fit on EELV, so as to save the development cost of a new rocket and get moving faster with the rest of the architecture. But an Emperor living in the past and intent on building Cathedrals let his ego get in the way and missed his chance at establishing a sustainable legacy.