The Debate Continues: Water or Land Landings for Orion
Written by Nancy Atkinson
The development of Constellation is continuing, the U.S. program that will replace the shuttle and send astronauts back to the moon. Two unresolved issues have stood out specifically for the Orion crew vehicle: Orion is currently too heavy for the Ares vehicle to launch it from Earth, and the decision on whether Orion will land in water or on land has yet to be determined. Originally, land landings were the preferred choice, but last December, it appeared program managers were leaning towards returning to the water landings seen during the Apollo era. But recently NASASpaceflight.com reported on a possible solution for the weight problem that could potentially provide an improved capacity for landing on land as well.
Needing to save mass on Orion to make it lighter prompted engineers to re-design the airbags that would be part of the vehicle to as a “contingency Land Landing requirement,” according to the article on NASASpaceflight.com. The new airbag system uses a smaller number of airbags than the original concept. As a result, the new airbag system is lighter. Engineers believe the new “back-up” system could possibly work well enough to be the primary system and allow land landings to be what NASA calls “nominal,” or the primary, preferred means of landing.
The upside of landing on land is that there’s a better chance of being able to reuse the command module, as opposed to landing in the ocean. Additionally, there’s some who believe returning to water landings is a step backwards for human spaceflight.
The airbags in the proposed new design are deployed out of the lower conical backshell on the Orion vehicle. Just before landing , the airbags would inflate and wrap around the low hanging corner of the heat shield. Upon landing, the airbags are vented at a specific pressure so that they collapse at a controlled rate to ease off the energy load of the spacecraft.
Although this new system has yet to undergo detailed analysis, initial results are viewed as promising on the ability to reduce crew loads to an acceptable level.
NASASpaceflight.com reported that another notable challenge for the Orion vehicle relates to maintaining the spacecraft’s orientation to minimize chance of tumbling during descent. A Reaction Control System (RCS) is being developed, which supposedly is preferred by engineers over retro rockets.
NASA did report last week the successful first full-scale rocket motor test for Orion's launch abort system. This system would separate the crew module from Ares if an emergency occurred during launch.
Original News Source: NASASpaceflight.com
Filed under: Astronomy
April 20th, 2008 at 1:15 pm
Moon exploration for NASA is not making sense. I realize we're still in the early developmental stages of Orion and Ares, but so far I do not see much evidence supporting a mission that will be seen to conclusion. If we want to return to the moon so bad, leave it up to the constituency to develop a privatized plan. That will inject much needed capital which could potentially be used toward the presumptive next phase, Mars. NASA has two major stumbling blocks that it will never overcome. The first is a budget subsidized by taxpayers. The second is perception–very few if any in congress understand science and consistently view NASA as an easy target for budget cuts. Even if NASA develops Orion and Ares, who's to say that the next round of so-called public servants won't change their minds and decide to rearrange NASA's priorities? It's happened in every modern presidential administration. I'm all for going back to the moon and eventually to Mars, but I'd rather see it done privately–at least we would have a better chance of seeing it happen.
April 20th, 2008 at 6:36 pm
We just need to convince the Bush Administration that there are WMD's and Oil on the Moon. We'd have 150,000 Soldiers and Prospectors there in two weeks, and an entire Carrier Group in Orbit around it.
I know it seems ridiculous but the only way I see the Government making an honest effort to support this venture is by selling it as a Military endeavor.
A large percentage of notable historic ventures have been undertaken by Military agents and as such they always have consistent financial backing.
I know that to undertake such an ambitious and costly task would be difficult to say the least, but at this point, our every effort seems a lot like floundering in a deepening quagmire.
April 20th, 2008 at 10:45 pm
Silver Thread
Though I heartily agree with you . . .
Our steps beyond Earth will be furtive and take ever so much more time that we have patience for.
Perhaps not voting for conservatives (ever, for the rest of your natural life) would help!
A Progressive leadership is about hope, and not fear. Our own Moon, Mars and the moons of Jupiter are about hope and the human spirit. People seem to think that conservative leaders offer security, when really the offer war . . . on something.
As a Junior Scientist Boy, I have vowed to support what science teaches us (proof, verification, peer review) and especially to avoid the emotional arguments of Neocons and Theocons (as these individuals are true butt monkeys!).
My hope is that corporate cost over-runs and multiple layers of subcontractors do not kill the plan, in the end. It is a very pragmatic approach, after all.
Me . . . I like the "Mars Direct Plan.
April 21st, 2008 at 5:49 am
Why not freshwater landings?
The Great Lakes are inconveniently far from Florida (and the most orbits), but they're very large targets. If the orbital/reentry mechanics work out, I'll bet a spacecraft will be much more reuseable after a freshwater dunking.
You'd need more floatation (fresh water is less dense), but that has to be easier to deal with than a ground impact…
April 21st, 2008 at 6:10 am
Great lakes? Great idea. Maybe the capsule can go off target like Russian entertainment and slam into the Sears Tower or in the middle of a Bears football game.
April 21st, 2008 at 6:44 am
Alien Overlord: Lake Superior is more what I had in mind… It would have to go FAR off-target to miss that lake.
And of course, the off-target problem exists for ground landings as well. Hitting Phoenix instead of the desert might not be ideal.
April 21st, 2008 at 11:23 am
This is depressing. It really seems like a step backward in either direction. Why cannot we not have a nice aerodynamic dead stick landing on a runway? The Dynasoar was designed way in the 60's! And we certainly have a lot of experience at it. Hell, it seems by now, we would consider a jet engine in case the vehicle has to be "waved off" for a second try at the landing.
This is a retro design, done on the cheap.
April 21st, 2008 at 11:29 am
Vanamonde - as I understand it (I am not a rocket scientist) wings suck. They're dead weight on the way up and in orbit, where every gram of wing is at least 1 gram less of payload.
And having wings, the vehicle has a much more complex shape on re-entry, leading to hotspots you need to use crazy fragile stuff like RCC joints to try to shield against.
Capsules have a much better aerodynamic shape on the way up, and (as I understand it) and easier-to-shield shape on the way down.
Of course, steering would be nice, agreed. But I don't think anyone makes space-capsule-sized parasails.