Lightening the Load
When you’re designing rocket systems, one of the first things you need to consider is how much mass you’ll need to separate from the Earth’s gravity. Of the hot issues plaguing the design and planning teams of the Ares I launch vehicle is just how much weight each stage and the accompanying Orion modules will add to the payload. Some have wondered whether it will be powerful enough to do the job. The passing of the current design past the first stage of requirements review on the 4th of January confirms NASA’s official confidence in the baseline drafts.
Constellation Program Manager, Jeff Hanley, might be the first person to tell you that an evaluation process is just that — a little give and a little take. In a November memo, sent after an internet rumor began to spread that Ares I wasn’t up to the task, he wrote, “Both the Ares I performance and the Orion control mass are ‘watch items’ on our list of top program risks. This is NORMAL for any such development effort….”
He brings up a good point. Since the dawn of space flight, ocean going vessels before and even wagon trains; what to take and what to leave behind can be a heart-wrenching decision. Every single mission is carefully considered with many useful items and experiments left behind. Experiments that have taken an entire career to design and assemble for a lift into space can be nixxed at the last moment if any one of about a million variables gives the launch crew any reason to think they need to increase the thrust margin.
The focus of the Constellation project is placed firmly upon safety. NASA is not even a little interested in loosing any more astronauts or ground personal to disasters like those that befell Columbia or Challenger. As such, they’re sacrificing some hauling capacity for safety. There is a 15% cushion built into all estimates, to ensure plenty of headroom.
Systems that have added to Orion’s weight include such features as the new launch abort system (LAS), currently weighing in at a portly 13,400 pounds. However, since it is discarded well before heading on to the lunar trajectory of particular concern to engineers. The “effective launch weight” comes out to only slightly more than 1600 pounds. It’s a good thing someone is good enough at math to figure all that out. Non-engineers among us hope they didn’t consult an accountant for their figures.
Able to lift over 58,000 pounds into Lunar orbit, Ares I is not the part of the venture that’s taking on ballast — the Orion module has been packing on the pounds since last Autumn. Now that designs are a bit more solid, it’s now time to start chucking things out and figure out how to do without them.
This entry was posted on Thursday, February 1st, 2007 at 1:35 am and is filed under Public Relations, Technical Concerns, The Gear to Get There. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
