Online hosting specialist Rackspace Hosting (NYSE: RAX) is dead set on becoming a powerhouse in cloud computing services. Today, Rackspace took the Nebula code that runs NASA's cloud-computing services and made it open-source. Anyone can use, modify, and profit from using that code, developed in a close partnership between the space agency and the computing expert. Rackspace hopes to make Nebula a de facto standard for running scientific computing services in the cloud.

In this, NASA and Rackspace don't stand alone. More than 25 companies, large and small, joined the duo in launching the Nebula standard. The roster includes big-name authorities Dell (Nasdaq: DELL) and Intel (Nasdaq: INTC), virtual computing veteran Citrix Systems (Nasdaq: CTXS), and others.

That's a broad enough support base to give Rackspace a chance here. It won't be an easy battle, though; Amazon.com (Nasdaq: AMZN) announced a sturdy scientific cloud platform of its own just the other week. You'll notice that Amazon isn't on board with the Rackspace standardization effort.

Other missing names shed some more light on the proceedings: Microsoft (Nasdaq: MSFT) is busy promoting its own Windows Azure cloud platform, while VMware (NYSE: VMW) theoretically could have shown up in the Rackspace corner, but didn't. Citrix could benefit if Nebula takes off into the stratosphere, given the prominent place of its Xen virtualization software in this offering and the relatively small size of the company. It doesn't take a huge hit to move the needle of a company with less than $9 billion under its market cap.

Where would you wager your chips in the ongoing struggle for cloud domination? Place your bets in the comments below.