WASHINGTON โ€” U.S. Sen. Barbara Mikulski (D-Md.), who chairs the Senate Appropriations commerce, justice, science subcommittee that oversees NASA spending, said astronaut safety, mission destination and work force transition would be among a half-dozen core principles she will use to draft the agencyโ€™s 2011 appropriations bill.

In a Feb. 16 letter to Sen. Bill Nelson (D-Fla.), chairman of the Senate Commerce science and space subcommittee, Mikulski said she would be looking to the authorizing committeeโ€™s close examination of President Barack Obamaโ€™s $19 billion spending proposal for NASA in 2011, which would scrap the agencyโ€™s Moon-bound Constellation program in favor of fostering development of a commercial crew transportation service to low Earth orbit.

โ€œThe Administration has proposed a new direction for Americaโ€™s space program and I believe it is now more important than ever for the Commerce and Appropriations Committees to work in consultation as we consider the Administrationโ€™s proposals,โ€ she wrote, adding that she thought it might be helpful to share with Nelson the โ€œprinciples that I will rely on when drafting the fiscal year 2011 funding bill for NASA.โ€

Chief among those principles is astronaut safety, which Mikulski said must be assured by the system NASA chooses for transporting astronauts to low Earth orbit.

โ€œThis means whichever transportation system is chosen, it must protect astronauts during launch, mission execution and re-entry, including during long duration space flight,โ€ she wrote.

Mikulski also stressed the importance of having a clear destination for NASAโ€™s human spaceflight program.

โ€œSince NASAโ€™s creation, it has been a mission driven agency, and I believe having a clear direction and destination has contributed to NASAโ€™s many successes,โ€ she wrote. โ€œNASA must continue to have a mission driven focus. To the maximum extent practicable, we should engage our international partners in formulating common destinations for human and robotic missions.โ€

Mikulski said she believes the space program must be balanced, and that science should continue to be its driving purpose. โ€œThis means human space flight that includes a safe, reliable vehicle, Earth and space scientific exploration, and aeronautics research and technology development,โ€ she wrote. โ€œThese objectives must be appropriately balanced in any future authorization or appropriations legislation.โ€

NASA should also maximize its current and future scientific assets in โ€œlow earth orbit and beyond.โ€

โ€œThis includes the extension of the International Space Station (ISS), which should be re-supplied with cargo by commercial vehicles,โ€ she wrote. โ€œAs we witnessed with the Hubble Space Telescope, a human space flight program dedicated to the advancement of science yields truly extraordinary results for the United States and the entire world.โ€

Nelson, who has criticized the presidentโ€™s plan to abandon Constellation and the Ares family of rockets being developed to support it, shares Mikulskiโ€™s desire to sustain the nationโ€™s status as a global tech leader through human spaceflight missions.

โ€œBetween them there is a common interest in making sure the U.S. maintains its leadership in science and technology via manned space exploration,โ€ Dan McLaughlin, Nelsonโ€™s press secretary, told Space News Feb. 19.

Nelson is also concerned with NASAโ€™s plan to transition the space shuttle work force once the agencyโ€™s aging fleet of orbiters retires later this year. His state stands to lose nearly 7,000 jobs as a result of shuttle retirement.

In her letter, Mikulski said plans to retire the space shuttle should proceed after assembly of the international space station is complete this year, but added that any future direction must include a plan to maintain critical skills and incorporate lessons learned from our previous efforts to replace the shuttle, โ€œand to soften any job dislocation impacts.โ€

When administration officials appear before her subcommittee to defend Obamaโ€™s proposal, Mikulski said, she will question where NASA is planning to go, how it will get there, and what it will take. She also wants to know if Obamaโ€™s intention is to โ€œscrap everything and start over,โ€ according to the letter. If so, Mikulski expects a plan to mitigate job dislocation and answers as to how the shift in direction will protect investments in Earth and space science and aeronautics proposed in the 2011 budget request and in the years ahead.

Mikulski intends to hold her subcommitteeโ€™s first NASA hearing on the 2011 budget March 25, according to an aide to the senator.

Nelsonโ€™s subcommittee will hold its first NASA hearing on the proposed budget Feb. 24.