Sens. Christopher Bond (R-Mo.) and Barbara Mikulski (D-Md.), the chairman and ranking member, respectively, of the Senate Appropriations VA, HUD and independent agencies subcommittee, asked the U.S. General Accounting Office in a March 11 letter to review the NASA decision. In a separate letter to NASA Administrator Sean OKeefe, also dated March 11, the lawmakers called for a review by the National Academy of Sciences and requested that the agency continue preparations for the Hubble servicing mission in the meantime.

Copies of the letters were released March 11 at a hearing of the subcommittee.

OKeefe announced the cancellation of the last planned Hubble servicing mission Jan. 16, citing the risks involved in sending the space shuttle to destinations other than the international space station in light of the findings of the Columbia Accident Investigation Board. OKeefe subsequently asked retired U.S. Navy Adm. Harold Gehman, who chaired the Columbia board, to review his decision.

In his March 5 response, a copy of which also was released at the hearing, Gehman said a Hubble servicing mission may be slightly more risky then flying shuttle missions to the international space station.

Gehman added: I suggest only a deep and rich study of the entire gains/risk equation can answer the question of whether an extension of the life of the wonderful Hubble Telescope is worth the risk involved.