Ares I-X sits on launch pad 39B. Credit: NASA

At 8:00 a.m.* EDT tomorrow, October 27, NASA will launch a test rocket called Ares I-X from Kennedy Space Center in Florida. The rocket is the first new launch vehicle to be tested in nearly four decades and the test will gather data critical to the design and development of Ares I--NASA's new rocket designed to replace the aging space shuttles and take humans to the moon, and possibly to Mars and beyond as part of the Constellation program.

Last week it took engineers almost seven hours to roll Ares I-X to launch pad 39B where it completed its flight readiness review. Now NASA's biggest concern for lift off is the weather. The agency has a four hour launch window, and while it only needs 10 minutes of clear skies for a "go", the forecasters are calling for 60 percent chance of clouds. If the launch is scrubbed, engineers will try again on Wednesday.

The test flight comes at a trying time for NASA, after its plan for the future of human exploration underwent an independent review and the outcome did not favor the Ares I. Despite these findings, NASA officials support the test flight, saying the data gathered will be useful for the design of any future rocket.

"This is the first time in more than 30 years that NASA has built a vehicle in a new configuration so this has been a valuable learning experience," said Doug Cooke, associate administrator for NASA Exploration Systems Mission Directorate in a press release."This test will yield important data to support the nation's next steps in exploration. There is no substitute for hard data--flight testing clarifies the distinction between imagined outcomes and real flight experience."

Follow the launch on Twitter, and the Ares I-X blog, then return to Delta-V for a post-flight analysis.

*Update 8:49 a.m, 10/27.: The launch has been delayed, scheduled for 9:24 a.m.. A rain shower is expected to pass over the launch pad at 9:50 a.m., which could cause further delays if not launched as currrently scheduled.

*Update 9:39 a.m.: There is a cargo ship in the Atlantic Ocean "danger zone", so launch is now scheduled for 9:49 a.m.

*Update 9:54 a.m.: NASA is now waiting for a break in the clouds for flight. The weather aircraft is making its flight and NASA will announce a new launch time in 5 minutes.

*Update 10:35 a.m.: New launch time is 10:54 a.m., but weather forecasters not so confident the skies will hold.

*Update 11:26 a.m.: Today's launch attempt has been scrubbed due to weather. NASA will try again tomorrow, October 28, starting at 8:00 a.m. EDT.

Today's release of the final report of the Augustine Commission--a blue-ribbon panel charged with reviewing America's human spaceflight program--contains a laundry list of possible future options for the White House and Congress to consider. While making explicit recommendations was outside the Commission's charter, the panel's members managed to make their feelings clear on at least a few points.

For example, take the Ares-I, the light launcher intended to ferry crews to the International Space Station. Pictures of the feasible future are painted in the report, pictures in which the Ares-1 is conspicous by its absence. Instead, the Commission appears to believe that commercial companies should fly crews and cargos into orbit, but it if they fail to deliver, a combination of the Orion Crew Exploration Vehicle and a cut-down human-rated version of the Ares-V heavy-lift launcher (both intended for exploration missions beyond low Earth orbit) could fill in. Noting that crew transport to low Earth orbit requires a vehicle not much more complex than the Gemini spacecraft that was developed in the mid 1960s, the report states that a commericial crew launch service could be in operation as early as 2016.

An artist's impression of a rocket destined for a journey beyond Low Earth Orbit being refueled at this space depot designed by Boeing.

On the positive side, the panel is clearly taken with the potential of in-space refueling technology, which enables spacecraft to tank up in low Earth orbit. With this technology smaller (and cheaper) rockets could be used for missions that would otherwise be outside their weight class and larger rockets would have their capabilities considerably enhanced. For example, without in-space refueling, a launcher derived from today's smaller expendable rockets could launch 26 tonnes towards the Moon. With in-space refueling that figure would more than double to 55 tonnes. For missions using the Ares-V, which will be able to launch 63 tonnes to the Moon unaided, in-space refueling could bring the capacity up to 130 tonnes.

The panel also claims that pursing this technology could provide a boost to the private space sector, if NASA purchased fuel in orbit from commercial companies which would operate refueling tankers or possibly even permanent depots. (It's not too much of a stretch to imagine that tourist facilties could be combined with these depots, creating multiple revenue streams for future orbtial entreprenuers.)

The report is a big vote of confidence in a technology that has been somewhat neglected by the U.S.. Russia has been performing in-space refueling of its space stations using Progress vehicles since 1978, but the U.S. has conducted only a handful of research projects over the years in this area. Most notable of these is the military's Orbital Express mission in 2007, which demonstrated the in-space refueling of a satellite, and work done at the Creek Road Cryogenic Research Complex at NASA's Glenn Research Center, which is developing ways to refuel spacecraft in orbit with high-energy cryogenic fuels such as liquid hydrogen and oxygen.

So while the arguments rage about one launch vehicle over the other, or one destination versus the next, we hope that funding becomes available to develop this eminently feasible technology which has the ability to enhance America's future in space, whatever direction is ultimately chosen.

In my coverage of NASA's successor to the space shuttle, the Ares rocket, and the next crew capsule, Orion, I have come across a common theme: vibrations.

While it may seem like a simple concept, vibrations or shaking can have a very powerful effect on a rocket's avionics, hardware, and any humans onboard. They come from such sources as the thrust of the solid rocket motors or boosters at lift off and even during flight, the burning of rocket propellant, and the sheer speed at which the rocket travels--over four times the speed of sound.

NASA's Dan Kanigan does a great job of explaining vibrations and their effect on the Ares I-X test flight rocket in this blog post. In addition, he talks about NASA's solution to the problem.

The vibration that is produced by the burning of the solid rocket propellant in the first stage booster is called thrust oscillation. These vibrations -- or oscillations -- come in the form of waves, which travel up and down the length of the rocket like a musical note through an organ pipe. One of the biggest challenges in any rocket design is developing avionics (aviation electronics) that can function in this vibrating environment.

Vibration is not just a rocket issue, though. All electronic hardware is tested for its ability to handle shock and vibration. An MP3 player, for example, has to be tested for its ability to handle the vibrations from someone walking or jogging while holding it, placing it on a countertop, or accidentally dropping it on the floor. However, compared to the workout that Ares I-X's avionics receive, your MP3 player has got it easy. Imagine shaking that MP3 player inside an automatic paint can shaker for two minutes while continuing to play your favorite tunes. That's kind of what the electronics of the I-X are up against.

Jon Cowart, the deputy project manager for Ares I-X at Kennedy Space Center, said in an interview earlier this year, that gathering data such as aerodynamic data, stresses, strains, pressures, temperatures, and vibrations is the most important part of the rocket's mission, and it will be used to make the Ares I even better.

Yet, the Ares I-X is just one example. NASA has been fighting the vibration issue since Apollo. Then such longitudinal oscillations caused by the burn out of the first stage booster were referred to as the "Pogo effect" and were especially troublesome for Saturn V. During an unmanned Apollo 6 flight, a critical test before manned flights could be approved, vibrations actually caused the main engine to shut down.

The new launch abort systems being built for NASA's Orion crew exploration vehicle is facing the same challenges. When the capsule and launch abort tower, which sits on top of the capsule, separate, a solid rocket motor called the abort motor fires, burning the propellant very rapidly to thrust the vehicle away from the rocket. The plume of hot gases emitted by the motor are the greatest source of noise and vibrations the vehicle will experience during flight, says Henri Fuhrmann, program manager of the new launch abort system at Orbital Sciences, an aerospace company that has partnered with NASA to design and develop the escape system. Thus the engineers have developed reverse-flow nozzles that turn the flow of the gases 155 degrees, away from the capsule. This will reduce the acoustics, vibrations, and loads on the capsule that could damage the electronics and hardware. This is the first time the technology has been developed at this scale, says Fuhrmann. The launch escape system on Apollo had direct flow motors and therefore had to add extra steel structures to increase the distance between the motor and the crew capsule. The Russian's launch escape system on the Soyuz spacecraft also uses direct flow nozzles.

Kanigan says that the next challenge is to make sure you can control the rocket at such vibrations. For NASA's new launch abort system engineers built a unique motor called the attitude control motor that steers and controls the capsule. It is also the first of its kind and can fly the vehicle forward and backward, and flip the capsule over to reorient it so the heat shield is facing forward.

Both Ares I-X and the Orion crew exploration vehicle are part of the Constellation Program, a plan to send humans to the moon and, then, to Mars. Norm Augustine, the chairman of a panel charged with reviewing this plan, said in a press briefing after the committee's first meeting where it heard ideas on alternative designs to the Ares rockets that the most interesting thing was the talk of how vibrations affect rocket design.