NASA has asked commercial space companies to explain how they would reach the Hubble Space Telescope, which has been in orbit for 36 years and is slowly falling out of it.
The agency released a Request For Information on Thursday, with responses due on 30 November. It asks about current and near-term capabilities for capturing Hubble and boosting it to an altitude of at least 373 miles, or 600km; for enhancing the telescope's performance; and for guiding Hubble to a controlled reentry.
"The requirement includes that the boost and/or servicing mission must not harm the HST and that this mission is expected to occur by 2032," NASA wrote in the document. A contractor would be responsible for the launch vehicle, the servicing spacecraft, mission operations and "crew if applicable".
Hubble has no onboard propulsion. Its orbit was last raised in 2002, when the Space Shuttle Columbia visited it; the final shuttle servicing flight, in 2009, did not reboost the telescope, and the fleet retired two years later. Since then it has simply been coming down.
It has taken 24 years to glide from the 362 miles, or 583km, it reached in 2002 to roughly 292 miles, or 470km, today. Orbital dynamicists expect reentry in 2033 or 2034 without intervention, although those forecasts move with solar activity. A lift to 600km would probably keep the telescope up for at least another 25 years.
The agency has been here before. It issued a similar request in 2022 and received eight responses, among them a joint robotic reboost proposal from Astroscale and Momentus. In 2024 officials decided not to pursue a mission; Mark Clampin, then the head of NASA's astrophysics division, said the servicing plans put to the agency by Jared Isaacman and SpaceX "were really just notional concepts".
Isaacman, who in 2022 offered to fund most of a crewed Dragon mission that would have raised Hubble by at least 30 miles, is now the NASA administrator. "Hubble still has important science ahead of it, and we should be looking at every reasonable opportunity to keep it delivering for as long as possible," he said in a NASA statement. He has written that he expects the new request to draw interest from robotics companies; SpaceX aims to retire its Crew Dragon fleet by 2030.
Nicky Fox, NASA's associate administrator for science, said: "Commercial industry has rapidly evolved in recent years to offer new capabilities for in-space satellite capture and servicing. Given the time we have until Hubble's anticipated reentry, we are eager to explore the breadth of possibilities to boost Hubble to a higher orbit while we develop the flagship mission to follow."
There is precedent at a smaller scale. NASA gave the startup Katalyst Space Technologies $30m and nine months to rescue its Swift telescope. Katalyst built and launched a spacecraft inside the deadline and closed to within about six miles of the target before ground teams decided not to go nearer, after problems with the craft's power and reaction control systems. NASA has no funding allocated for a Hubble mission.
The request is unusual in that it treats two opposite outcomes as one procurement. A company may propose to lift Hubble into a higher orbit. It may instead propose to bring Hubble down and burn it up on a schedule of NASA's choosing. Both are answers to the same document, and both are governed by the same stated requirement: the mission must not harm the HST.
This newspaper has read that requirement several times. A controlled reentry destroys the telescope. It must nonetheless be carried out without harming it. The distinction, so far as we can establish, is one of paperwork rather than physics.
The deadline is similarly precise. Any mission is expected to occur by 2032, which is one year before the earliest predicted reentry. The telescope has therefore set the delivery date, and it has done so by falling at a known rate for 24 years without being consulted.
Our analysts note that the thing now destroying Hubble is patience. Over a quarter of a century it has shed about 70 miles of altitude, which no engineering firm would be paid to achieve and which no contract would describe as a capability.
The Department of Unnecessary Research has filed its own response to the Request For Information. It proposes doing nothing, by 2033 or 2034, at no cost, and concedes that this is the only submission certain to harm the telescope.