CAPE CANAVERAL, Fla. (Reuters) - Corporate researchers may be living on the moon by the time NASA astronauts head off to visit an asteroid in the 2020s, a study of future human missions unveiled on May 23 shows.

The study by Bigelow Aerospace, commissioned by NASA, shows "a lot of excitement and interest from various companies" for such ventures, said Robert Bigelow, founder and president of the Las Vegas-based firm.

The projects range from pharmaceutical research aboard Earth-orbiting habitats, to missions to the moon's surface, he said on Thursday, citing a draft of the report due to be released in a few weeks.

NASA intends to follow the International Space Station program with astronaut visits to an asteroid by 2025 and to Mars about a decade later.

President Barack Obama's proposed budget for the fiscal year beginning Oct. 1 requests $105 million for the U.S. space agency to begin work on a mission to find a small asteroid and reposition it around the moon for a future visit by astronauts.

But private companies, including Bigelow Aerospace, have more interest in the moon itself, Bigelow told reporters on a conference call on Thursday.

William Gerstenmaier, NASA's head of space operations, said on the call "it's important for us to know that there's some interest in moon activity and lunar surface activity."

"We can take advantage of what the private sector is doing" in areas such as space transportation, life support systems and other technologies needed for travel beyond the space station's 250 mile (400 km) high orbit, he noted.

NASA typically completes its mission planning before looking at what partnerships and collaborations may be possible, Gerstenmaier added.

"We thought that this time we would kind of turn that around a little bit, that we would ask industry first what they're interested in ... where they see human presence that makes sense, where they see potential commercial markets."

Bigelow Aerospace surveyed about 20 companies as well as foreign space agencies and research organizations for the NASA study, which the company undertook at its own expense. Bigelow has made no secret of its ambition to own, lease and operate inflatable space habitats in Earth orbit and on the moon.

Bigelow handed a draft of the first part of the report to Gerstenmaier on Thursday, 40 days ahead of schedule. The second section, which probes mission planning and other aspects of potential public-private partnerships, is due this fall.

(Editing by Tom Brown and Richard Chang)