Mark S. says:

I just finished listening to this podcast. While I think Jeph did alright, he didn’t hit the main advantage of DIRECT over ARES. Namely, that DIRECT develops a single common core booster and flies it in two different configurations. The Jupiter-130 is the single stage version shown in the graphic, and the Jupiter-246 is the exact same core with an upper stage added for additional capacity. Jupiter uses the same tooling and production lines as the Space Shuttle for the core stage, with a new line for building the upper stage when the Lunar phase starts.

ARES, on the other hand, develops two completely different launchers that have almost nothing in common with each other, or with Shuttle. There will be two separate development efforts, two production lines, two sets of tooling and expertise, two different high-bay configurations in the VAB, two different mobile launch pads, two different launch towers, etc etc. Needless to say, all that duplication of effort costs tons of money and time.

The Jupiter cores are identical and can be interchanged as needed. The J-130 flies with three SSMEs, and the J-246 launches with four. Jupiter has much more in common with Shuttle, and does not require any engine development at all. The boosters are identical to the Shuttle, the core tank is closely derived from the Shuttle ET, the main engines are SSMEs, and LEO missions do not require an upper stage at all. In fact, the J-130 can launch 40 additional metric tons to LEO, with a fully functional six-crew Orion.

The J-246 adds an upper stage with six RL10B2 engines borrowed from Centaur, which gives it the ability to lift 110 metric tons to LEO. The DIRECT plan calls for two J-246 launches for Lunar missions, with a combined capacity of 220 metric tons. ARES, on the other hand, is planned to use an Ares-I and an Ares-V for Lunar missions, with a combined capacity of 218 metric tons to LEO, so they are very comparable.

And that’s not even taking into consideration all of the problems that the ARES development teams have been having! Three years in and Ares-I hasn’t even completed its PDR yet. We’re still waiting on a “delta” PDR to take into account the changes made to handle the Thrust Oscillation problem. And Ares-V is still very much in the “paper rocket” stage. NASA’s specifications for Ares-V simply list what it will be required to lift in order to fulfill its mission. They don’t really have a good handle on how to actually make it work.

This post is already too long, please go to http://www.directlauncher.com for more details.

Thanks,
Mark S.

Ross says:

As one of the DIRECT spokesmen, I would have liked a chance to field a few of those questions myself!

If you would like a future interview, drop me a line.

Jose Reis says:

This a simple, clean and easy to adapt desing. It’s based on engines and boosters of the proven Shuttle, why start on something new when there is no guarantee that it will work. We all know when the russian rocket first desing (mid-1950s) and they still use it!

I didn’t know about this project until today and I have to say that it does look a lot smarter and cost saving than Ares.

Mike DeMarco says:

I almost agree with Tex. But, why not impliment Jupiter, and supliment it with Ares I ? Jupiter 130 (with its heavy-Orion and payload capability) is needed badly for ISS, Hubble-repair, etc. missions, and Ares I can be developed secondarily as an additional cost-saving measure for quick ISS access at a later date.