The Debate Continues: Water or Land Landings for Orion

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