Chasing satellites

The next repair mission was a case of tidying up unfinished business - rescuing the pair of mis-deployed satellites released during the STS-41B mission in February 1984 (see p.194). Both had fallen far short of their intended orbits after their Payload Assist Modules (PAMs) had failed. After a brief pause in commercial launches while the problem was sorted out, the maiden flight of Discovery in August had flawlessly deployed another pair of communications satellites. With the PAM problem apparently resolved, Discovery's second mission, STS-51A, in November 1984, was to retrieve the stranded satellites for a refit on the ground. A difficult mission, requiring the chase-down and capture of two separate satellites, was made harder still by the lack of grips on the satellites - unlike SolarMax, they had not been built with in-flight servicing in mind.

The STS-51D mission offered a great demonstration of the Shuttle's flexibility. In April 1985, Discovery released a US Navy Leasat communications satellite

13-15 November 1984

Discovery retrieves the Westar-VI and Palapa B-2 satellites, deployed by Challenger in February, for a refit back on Earth.

visor down helmet lights

PLSS life-support unit

EXTRAVEHICULAR MOBILITY UNIT

The Extravehicular Mobility Unit (EMU) spacesuits of the Shuttle era ore very different from those used on Apollo. Designed for work in weightless conditions, they have a hard upper torso unit and an integrated PLSS backpack.

cuff checklist

2 December 1993

Endeavour is launched on the first of several servicing missions to the Hubble Space Telescope.

Hard Upper Torso (HUT)

two-part glove assembly

13 May 1992

Endeavour captures and repairs the 4.2-tonnne Intelsat VI satellite as part of the STS-49 mission.

Lower Torso Assembly (LTA) including legs harness attachment integrated boots

Situated 35,786km (22,240 miles) above the Earth's equator, NASA's Tracking and Data Relay Satellites orbit the Earth once each day, acting as relay stations for data from faster-orbiting satellites and spacecraft closer to Earth. Seen from Earth, each TDRS remains stationary in the sky - a fixed platform through which data can be sent and received from satellites at lower altitude. Moving a small antenna on a vehicle such as the Space Shuttle in order to track each TDRS is far easier than tracking the Shuttle from the ground as it speeds across the sky.

from the cargo bay, only to see it spin away without power as a switch intended to trigger its built-in kick motor failed to activate. Rather than abandon the satellite, the mission was extended - the satellite was chased down, and a spacewalk was improvised in which the astronauts attempted to trigger the switch manually. In the end, the switch failed to wake the satellite but the astronauts' assessment paved the way for repair by Discovery a few months later.

Following the hiatus caused by the Challenger disaster in January 1986 (see p.202) it was some time before NASA attempted any further satellite repairs (see p.207). When it came, however, it was truly spectacular, as Endeavour caught up with and retrieved the enormous Intelsat VI communications satellite. Experience in handling this giant in space paved the way for the even more ambitious repair missions that would be needed to help maintain the Hubble Space Telescope (see pp.252-53).

EXTRAVEHICULAR MOBILITY UNIT

The Extravehicular Mobility Unit (EMU) spacesuits of the Shuttle era ore very different from those used on Apollo. Designed for work in weightless conditions, they have a hard upper torso unit and an integrated PLSS backpack.

integrated boots cuff checklist

3 February 1984

Two communications satellites deployed from Challenger fail to reach their intended orbit after a rocket motor failure.

8 April 1984

Challenger captures and repairs the SolarMax satellite - the first ever satellite maintenance in orbit.

13-15 November 1984

Discovery retrieves the Westar-VI and Palapa B-2 satellites, deployed by Challenger in February, for a refit back on Earth.

16 April 1985

Discovery chases down and attempts to repair the faulty Leasat-3 communications satellite launched earlier in this STS-51D mission.

31 August 1985

Discovery's STS-511 mission successfully helmet with Sun recaptures and "hotwires"

visor down the Leasat-3 satellite.

2 December 1993

Endeavour is launched on the first of several servicing missions to the Hubble Space Telescope.

Hard Upper Torso (HUT)

two-part glove assembly

13 May 1992

Endeavour captures and repairs the 4.2-tonnne Intelsat VI satellite as part of the STS-49 mission.

Lower Torso Assembly (LTA) including legs harness attachment helmet lights

PLSS life-support unit

FATAL LIFTOFF

Cameras at pad 39-B photographed Challenger on its way to catastrophe. Residue from the SRB fuel formed a temporary seaI over the cracked O-ring, delaying the disaster.

FATAL LIFTOFF

Cameras at pad 39-B photographed Challenger on its way to catastrophe. Residue from the SRB fuel formed a temporary seaI over the cracked O-ring, delaying the disaster.

"Reality must take precedence over public relations, for nature cannot be fooled."

Richard Feynman's appendix to the Rogers Report, 1987

BIOGRAPHY

christa mcauliffe

NASA set up its Teacher in Space project in 1984, in an attempt to reignite public interest in space. Out of 11,500 applicants, Christa McAuliffe (1948-86), a Social Studies teacher at Concord High School, New Hampshire, was chosen for her inspirational teaching style. She began training in autumn 1985 and was welcomed to the team of the doomed STS-51L, dying with her six crewmates on 28 January 1986. In 2004, NASA began a new "educator astronaut" programme, and McAuliffe's original backup, Barbara Morgan, is now due to fly aboard STS-118.

The Challenger disaster

By the end of 1985, the Space Shuttle programme finally seemed to be getting into gear, with shorter intervals between flights and faster turnaround times for individual spacecraft - but then disaster struck.

BLOWTORCH EFFECT

Fifty-eight seconds after launch, ground-based cameras capture a superheated jet of flame emerging from a joint on Challenger's right SRB, burning through the vulnerable support strut.

The launch of Challenger's STS-51L mission on 28 January 1986 was the focus of unusual attention. It was the 25th flight, a minor landmark in itself, and was also carrying a notable passenger - Christa McAuliffe, from New Hampshire, had been selected to become the first teacher in space and would be delivering lessons over a live television link from the Shuttle to schools across the country.

But just 73 seconds after launch, both NASA and the general public were left reeling as Challenger exploded in mid-flight, instantly killing all seven astronauts onboard, showering debris across the Atlantic Ocean, and fatally undermining America's dreams of routine manned spaceflight.

BLOWTORCH EFFECT

Fifty-eight seconds after launch, ground-based cameras capture a superheated jet of flame emerging from a joint on Challenger's right SRB, burning through the vulnerable support strut.

WORKING IN SPACE

Accident investigation

Future Shuttle flights were immediately grounded while an investigation got under way. Television pictures soon revealed the direct cause of the accident - a jet of scalding flame emerging from

RICHARD FEYNMAN

ENTOMBMENT

Following the investigation, the recovered Challenger wreckage was buried in empty missile silos on Canaveral Air Force Station.

WORKING IN SPACE

Accident investigation

Future Shuttle flights were immediately grounded while an investigation got under way. Television pictures soon revealed the direct cause of the accident - a jet of scalding flame emerging from

GHOST OF THE CULPRIT

Search teams recovered 40 fragments of ** Challenger's SRBs, including a joint from the right-hand side that retained traces of O-ring seal tracks.

ENTOMBMENT

Following the investigation, the recovered Challenger wreckage was buried in empty missile silos on Canaveral Air Force Station.

RICHARD FEYNMAN

ll

957

958

959

Physicist Richard P. Feynman (1918-88), best known for his work on fundamental atomic forces, sat on the Rogers Commission into the Challenger disaster. He famously revealed the vulnerability of the SRB O-rings by dipping a sample of material into a jug of iced water, V then snapping it with his hands. Feynman's conclusions about the Shuttle's safety were even more damning than those of the official report, and were added as an appendix - his estimate of one failure in roughly every 50 missions was to prove tragically accurate.

the side of one of the SRBs and burning through one of the struts that held it to the rest of the launch assembly. As the strut gave way, the SRB had swung round, slamming into the external tank and rupturing it in a huge explosion that completely destroyed the spacecraft, instantly killing the crew.

Tracing the accident back to its origins, however, took longer. President Reagan appointed an investigation board, which included Neil Armstrong and Richard Feynman (see panel, above). They tracked the jet of flame back to a crack in one of the joints between sections of the right SRB - the night before launch, frost had formed on the Shuttle, and a rubber O-ring seal had become brittle and unable to fill the joint properly under the stress of launch.

However, the investigation did not stop there - it comprehensively tore apart NASA's managerial structure, attacking a culture of complacency in which the concerns of several engineers about the launch had become lost in bureaucracy and never reached the ears of key safety managers.

Although there was probably nothing that could have saved Challenger's crew in this exact chain of events, the board also recommended extensive changes to Shuttle hardware that would keep the spaceplane grounded for a total of 32 months. Challenger would be replaced - NASA had enough "spare parts" to put together a new Shuttle, Endeavour. But a more conservative launch policy would result in far longer turnaround times - putting an end to the optimistic estimates of launch rates on which the entire Shuttle concept was founded.

22 January 1986

STS-51L is scheduled for an afternoon launch but is delayed.

24 January 1986

More delays are caused by poor weather at an emergency landing site in Senegal. The abort site is moved to Casablanca, but this runway cannot handle a night landing, so the launch is moved to local morning. Later, poor weather forecasts at Cape Canaveral put the launch back still further.

27 January 1986

High winds force another delay. Forecasts of cold weather for next morning prompt engineers at SRB maker Morton Thiokol to call a teleconference with NASA managers regarding a possible problem with the O-rings. In the end, Thiokol's own management overrule the engineers and recommend that the launch should proceed.

28 January 1986

Challenger launches at 11:38 EST.

22 January 1986

STS-51L is scheduled for an afternoon launch but is delayed.

THE CREW

Photographed following a launch rehearsal on 8 January, Challenger's crew (left to right: McAuliffe, Jorvis, Resnik, Scobee, McNoir, Smith, and Onizuka) pose in the White Room next to the Shuttle hatch.

EXPERIENCE

THE CHALLENGER DISASTER

"Go at throttle up"

For those on the ground or watching the televised launch coverage, the explosion that destroyed Challenger came without warning. But the decision to launch had hung in the balance almost until the last moment.

Dick Scobee: Point nine. Michael Smith: There's Mach one.

DS: Going through nineteen thousand. Okay we're throttling down. Throttling up. MS: Throttle up. DS: Roger.

MS: Feel that mother go. DS: Woooohoooo.

MS: Thirty-five thousand going through one point five.

DS: Reading four eighty six on mine.

DS: Roger, go at throttle up.

MS: Uhoh [The line then goes dead].

THE CREW

Photographed following a launch rehearsal on 8 January, Challenger's crew (left to right: McAuliffe, Jorvis, Resnik, Scobee, McNoir, Smith, and Onizuka) pose in the White Room next to the Shuttle hatch.

On the morning of 28 January 1986, the crew of Challenger prepared for the launch from Cape Canaveral. Out on Pad 39B, the ice team had been working through the night to tackle frost forming on the Fixed Service Structure supporting Challenger. After a week of delays, there was an eagerness to get under way, although Rockwell, the Shuttle's main contractor, was now expressing concerns about launch safety. A hardware failure led to a two-hour delay, during which Program Manager Arnold Aldrich agreed to a further ice inspection at 10:30, but the engineers' worries about the 0-rings had not reached him, and when the ice appeared to be melting, he gave the go-ahead. The Shuttle launched at 11:38 EST, but a minute later disaster struck:

COUNTDOWN TO DISASTER

The Challenger crew had spent four months in training for their STS 51-L mission, but on the morning of 28 January, long icicles hod formed on the Shuttle's service structure. Debate about the effects of the ice continued even as the crew made their way to the Shuttle, and the final decision to go ahead came just 20 minutes before launch.

SHOCK IN THE CROWD

At first, spectators watching from the Launch Complex 39 Observation Gantry were unsure of the explosion's meaning - those who had never seen a Shuttle launch before had been told that SRB separation could be spectocular, and it took several moments to realize something had gone badly wrong.

MISSION CONTROL Staff at Johnson Space Center in Houston watch in stunned disbelief as their communications and telemetry disappeor and the television monitors reveal the awful reason why (main picture).

"One minute, fifteen seconds... Velocity twenty-nine hundred feet per second. Altitude nine nautical miles. Downrange distance seven nautical miles ... Obviously a major malfunction."

NASA launch commentary, 28 January 1986

We mourn seven heroes: state of mourning

Mirbapl ¬ęsmith Dirk President Ronold Reagan had been due ivncnaei omun, uick t0 gjve hjs state of the unjon address t0 Scobee, Judith Resnik, the notion on the niQhtof28January.

Konaia IVICIM BIT, ¬°0 a shocked and grieving nation.

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