Home

Ares I

Ares V

Lunar Mission

Architecture Benefits

Data Sheets

Myth Busters

News/Media/Links

Contact Us

By Rob Coppinger 02/03/08
http://www.flightglobal.com/articles/2008/03/02/221872/nasa-rebutts-ares-i-myths.html

Ares programme manager Steve Cook has debunked what he calls the "Ares myths" that critics have persistently assumed about the Moon mission launcher since it was unveiled in 2005: that the rocket does not have enough power, that its resonant burning oscillation will damage the Orion crew capsule and that the Ares will not be controllable in flight.

Speaking at NASA's third space exploration conference on 26 February in Denver, Colorado, Cook said that while the performance of the Ares I crew launch vehicle could be improved, Ares had a 2,200kg (4,400lb) performance margin over and above the lunar mission's requirement and 1,360kg performance margin over Orion's maximum mass needs that the oscillation issue was well known and would be solved and that after 4,200h of wind tunnel tests and the availability of heritage thrust vector control technology Ares I would be controllable in flight.

As for potential improvements, Cook spoke of a 609mm (24in) longer first-stage nozzle for an extra 590kg capability to Low Earth Orbit, a reduction in cryogenic tank wall thickness for the upper stage, for "extra several hundred pounds more performance", and for some missions the removal of the first-stage recovery system for a "significant capability increase".

Of a fourth myth — that the vehicle's development is not on schedule — Cook said: "We have hit all our milestones and are on track to hit [the preliminary design review] milestone in August 2008. We won't go into a review unless we're ready." However multiple NASA schedule documents obtined by Flight have shown a slippage of the PDR for Ares since early 2007.

The Ares Project Office has uploaded seven videos to the AresTV YouTube channel. The move to this popular outlet holds the potential of reaching thousands of new people, including "Gen Y" viewers who have made the site so popular. The videos feature recent progress in manufacturing, testing, and other projects activities.

The url is: http://youtube.com/user/AresTV

By Loretta Hidalgo Whitesides July 09, 2008
http://blog.wired.com/wiredscience/2008/07/why-nasa-isnt-t.html

Some commenters have raised a very reasonable question: Why doesn't NASA just human rate an expendable launch vehicle like the Atlas V or the Delta IV? It seems reasonable because they fly all the time, they are big, they are reliable and they are already built. So what is the problem?

Weight-

The Orion Crew Exploration Vehicle is too heavy for the Atlas V and the Delta IV (I will deal with other capsules after the jump). You also have to account for other mission constraints. For example, you have to include the loss of performance you get from going to the high inclination orbit of the International Space Station. ISS doesn't just fly directly over the equator but at an angle that allows it to pass over Russia. That orbit takes more energy to get to. In addition you will also lose performance because you have to fly a less aggressive launch profile. The current profile subjects payloads to 6 G's (Space Shuttle is 3 G's). Human payloads don't respond well to sustained 6 G loads. Flying a less aggressive profile will mean you will be able to lift less.

So all in all, you would need to develop a "triple-core" (three Atlas' strapped together) to be able to lift Orion. A triple core Atlas has never been flown. You would also need a new upper stage for an extra bit of kick at the end of the flight. The Delta IV, although larger and more mature, would also need a new upper stage.

Triple Redundancy-

All human-rated vehicles are designed to be triply redundant. If something fails, there has to be two other options for the crew. It's like when the power goes out at your house, you have a back-up system which is a flashlight. If the flashlight fails, you have a second back up system which is a bunch of candles and matches. Now, to be stuck in the dark you would need to have all three systems fail. Cargo rockets are not designed with that much redundancy in their systems. Adding in that kind of redundancy after the fact would be like getting under the hood of your car and installing a back-up set of brakes. You have to create feed throughs for the wires, try to figure out where you will put the extra brakes etc.

Now to be fair, you could launch a smaller human vehicle on a current expendable rocket...(Orion does seat six).

In fact, before the Columbia disaster NASA teams were working on an Orbital Space Plane (OSP) designed to do just that. At the time, OSP was maligned for being small and limited in capability. (It is ironic that the Orion is now being maligned for being too large and capable.) OSP was a smaller vehicle designed to launch on an Atlas V or a Delta IV and seat "no less than four" crew members. It was eventually overcome by events when Constellation and the Moon, Mars, and beyond program kicked off and NASA transferred the knowledge gained on the OSP to the development of Crew Exploration Vehicle.

Then there is Robert Bigelow, a self made millionaire, who is building an inflatable space module hotel (they already have a scale model on orbit now). He is converging on a deal with Lockheed Martin to human-rate a version of the Atlas V. This is plausible, given that they are looking for an OSP-class capability. Bigelow's main interest is getting clients to and from his future orbiting facilities.

SpaceX is also building a small capsule that could launch people to ISS or Bigelow's space modules hotel. Their Dragon capsule, being built to take cargo to the International Space Station, will fit on their Falcon 9 rocket and be able to launch humans. Although it will not fly on an Atlas or a Delta, it is in that same class of vehicles.

Perhaps in the end it is a good idea for NASA to focus their efforts on building the new, heavier Orion capsule and the Ares I and V. These vehicles are suitable for the longer, more demanding trips to the moon. Then NASA could leave the lighter, smaller low Earth orbit capsules to commercial space to work out. That would serve both the goal of NASA being an exploration agency and of evolving our commercial space sector.

So the short answer is: NASA is not human-rating an Atlas V because that system will not be sufficient for exploration beyond low Earth orbit (though Bigelow Aerospace is looking at human-rating the Atlas V).

By Rob Coppinger
http://www.flightglobal.com/articles/2008/07/08/225142/ares-i-to-get-extended-nozzle-lunar-variant.html

NASA is planning to extend its Ares I crew launch vehicle's solid rocket booster first-stage nozzle in time for the maiden lunar mission, to deliver improved performance.

The agency recently completed its preliminary design review for the booster's first stage, which will launch the Orion crew exploration vehicle to the International Space Station from March 2015.

However, the nozzle extension will be a later addition. In another change from the original plan, to have the same solid rocket booster for Ares I and the Ares V cargo launch vehicle's (CaLV) strap-on boosters, the CaLV's solid rockets are to be longer.

Extending the nozzle is "a requirement for lunar missions, beginning with the Orion 13 flight. The plan is to incorporate the extended exit cone in time to support that mission," says Ares I first-stage manager Alex Priskos.

The first-stage preliminary design review did not address the solid rocket booster's thrust oscillation problem because studies are still under way.

NASA may have a "delta" preliminary design review, according to Priskos, for subsystems addressing oscillation. The agency has proposed first-stage spring-loaded masses as one solution.

Due to the first-stage's launch acceleration, the rocket's umbilical connections will have Ares I specific designs and not heritage hardware.

Priskos says that "specific hardware interface responsibilities between Ares and ground operations have been defined", deciding who designs what, and that each design is at a "different point in design maturity".

Meanwhile, the first-stage drogue and other parachute drop tests' data gathered has been used to optimise reefing line lengths for the 2009 Ares I-X flight test and mature ongoing recovery system design work.