This Week in Rocket History is STS-82, the second servicing mission to the Hubble Space Telescope.

STS-82 was a demonstration of what the shuttle was always intended to do: bring humans to orbit to service a spacecraft designed for repair, instead of the many missions with just satellite deployments it had been doing which did not strictly require their presence. Hubble had been serviced once before to fix the major flaw in its mirror that prevented it from doing any science.

The repairs and upgrades on STS-82 were much less drastic, consisting mostly of swapping out functioning instruments for better ones using new technology developed after its launch and replacing broken components. The seven-member crew of Ken Bowersox, Scott Horowitz, Mark Lee, Steven Hawley, Steven Smith, Greg Harbaugh, and Joseph Tanner conducted five EVAs over the course of the almost ten-day mission. Tanner, Smith, Harbaugh, and Lee did all of the EVAs.

STS-82 launched on Shuttle Discovery from LC-39A at the Kennedy Space Complex in Florida on February 11, 1997. Discovery was the same orbiter that delivered Hubble to orbit in 1990. Discovery took two days to rendezvous and grapple the telescope using the Shuttle Remote Manipulator System, better known as the Canadarm, controlled by Steven Hawley. Hawley happened to be the one who released it into orbit the first time back in 1990.  

The astronauts performed one EVA each day of the mission. The first EVA took place on February 13 and lasted about six hours. The goal of the first EVA was to replace two instruments — the Goddard High-Resolution Spectrograph and the Faint Object Spectrograph. These were replaced with the Space Telescope Imaging Spectrograph( STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS).

The second EVA replaced some of the worn-out components, a fine guidance sensor, and a tape recorder. The astronauts also installed a new piece of equipment to improve the fine guidance sensor called the Optical Control Electronics Enhancement Kit.

The third EVA replaced more worn-out components, including another tape recorder with a digital storage device and a broken reaction wheel. Reaction wheels are used to point the telescope without using thrusters. Each solid-state recorder had ten times the storage capacity of the tape recorder it replaced, 12 gigabits or 1.5 gigabytes versus 1.2 gigabits or one hundred fifty thousand kilobytes. For comparison, 1.5 gigabytes is about the size of a standard definition movie. Another advantage of the solid-state recorder was the lack of moving parts to wear out.

One of the advantages of working in low-Earth orbit is close contact with ground control. After the third EVA, engineers on the ground decided to add a fifth EVA to the mission to repair part of the spacecraft noted as damaged on the second EVA.

The main goal of EVA four was to replace the electronics box which controlled the pointing of the solar panels and some of the damaged insulation. While the EVA was taking place, two of the non-spacewalking crewmembers made replacement insulation blankets to be installed on the fifth EVA.

The fifth and final EVA involved installing the new thermal insulation blankets to protect several critical components of the telescope from damage and thermal problems.

The five EVAs on STS-82 involved a total of 33 hours and 11 minutes, which was two hours less than the first servicing mission.

Before Discovery returned to Earth, it boosted Hubble, which has no thrusters of its own, up to a higher orbit using the shuttle’s small thrusters, rather than the larger orbital maneuvering engines so as not to disturb the sensitive telescope.

Wheel stop on STS-82 was 9 days, 23 hours, 37 minutes, and 9 seconds after take-off on the Shuttle Landing Facility runway at Kennedy Space Center in Florida. Discovery completed 150 orbits over that time.

NICMOS operated from its installation in 1997 until 1999 when it ran out of cryo coolant. It was replenished in 2002 during the STS-109 mission and operated until 2008 before failing again. It is still installed in the telescope.

STIS had an electronics failure in 2004, but it was repaired in 2009 during the STS-125 mission and is still operating as of 2022.

More Information

STS-82 (NASA)

NICMOS (Space Telescope Science Institute)

NASA attempts to revive Hubble’s main camera (New Scientist)