April 1982:space activities report

IUS UNITS DELIVERED

The first sections of the first Inertial Upper Stage (IUS) were delivered by Boeing to the US Air Force’s Eastern Lauch Site in Florida last December. The IUS will eventually serve as an upper stage for both the Titan III and Shuttle vehicles, with the first launch atop a Titan 34D this year.

The items delivered were the IUS’s equipment support section with all its avionics and other systems, and the interstage which will connect the two solid-fuel rocket engines.

The equipment support section bouses systems for guidance and navigation, telemetry, electrical power, tracking and command. It contains some 500 connectors and 4400 wires which, in total, stretch almost five miles.

Redundancy and parts quality are the key to the lUS's reliability, estimated to provide each vehicle with a 98 per cent chance of success. For instance, the equipment support section houses two identical master computers, each of which, in addition to being capable of controlling the vehicle’s mission, can isolate problems and circumvent them in milliseconds.

Other components which either have backup units or internal redundancy include guidance units, batteries, electrical power buses, antennae, telemetry units, inertial measurement units, signal conditioners and reaction control thrusters.

The two solid-fuel rocket motors, produced by the Chemical Systems Division of United Technologies, were delivered later for integration with the Boeing built segments to complete the IUS.

SPACE TELESCOPE MIRROR COATED

NASA’s Space Telescope has passed a major milestone in its development: the coating of the 94 inch primary mirror.

The Space Telescope, which will use two mirrors to focus light from stellar objects on to a group of scientific instruments at the rear of the telescope assembly, carries a 1800 lb primary mirror coated with aluminium three millionths-of-an inch thick.

The Perkin-Elmer Corporation, responsible for the design and production of the optical assembly, completed coating the primary mirror with the highly reflective metal on 5 December.

Engineers have since verified that the coating adheres to the mirror and has the proper reflectivity.

A NEW SPACE LAUNCHER?

NASA is considering using some of the Space Shuttle’s reusable features as part of an unmanned launch vehicle. The Shuttle’s recoverable solid rocket boosters (SRB’s) would make up the major segment of a launcher being studied by the Boeing Aerospace Company.

Under a one-year, $250,000 contract with the NASA Marshall Space Flight Center, Boeing engineers are searching for a concept that would use the Shuttle’s hardware and facilities with only minor modifications. Called the SRB-X, the proposed vehicle would use the solid rocket boosters, but not the Orbiter or external tank.

Although the Space Shuttle will be the primary launcher, it may need to share the load with another launch vehicle in a mixed-fleet operation. NASA is considering this idea because the Shuttle may have tight schedule requirements and payloads that may be too large or heavy when delivered to certain destinations.

The various SRB-X options being considered could deliver payloads weighing up to 65,000 lb to low Earth orbit (about 150 miles) or 12,000 lb to geosynchronous orbit. SRB-X would be tailored so that certain payloads could be interchangeable with the Shuttle and could be launched from Shuttle facilities at Kennedy Space Center or Vandcnberg Air Force Base. This would allow for early availability and low developmental costs.

The contract with the space agency is divided into two study areas. During the first six-month period, Boeing will study a large number of potential concepts using current or modified Shuttle boosters and selected upper stages. These concepts will be compared in terms of performance, mission utility and cost analysis. Upper stage and payload integration will be considered as well as ground operations and facility require¬ments. By the end of the phase, the engineers will have narrowed the field of options.

During the final six-month phase, the firm will define in greater detail those particular concepts that seem most promising and make a final selection and recommendation. The study results will then allow NASA to compare the recommended SRB-X concept with other Shuttle derived concepts.

KEY OF THE DOOR

At the conclusion of the STS-2 postflight press conference, Astronaut Office Chief John W. Young presented ceremonial keys for Columbia to the crew of STS-3. Jack'l.ousma described the mission of STS-3: “This time we will be up approximately seven days (116 orbits). And we will be doing essentially the same things that were done before but in addition there will be more work with the Canadian-built arm (the Remote Manipulator System). We will actually be picking up some payloads, and we have a really advanced scientific payload.’'

The payload known as OSS-1 (after the NASA Office of Space Science) is mounted on a U-shaped pallet, making up a 2,609 lb package. A drum-shaped experiment will stretch 45 ft out from the cargo bay attached to the end of the flexing robot arm. It will help engineers to discover just how rough a wake Columbia produces in its journey through an ocean of atomic particles.

The 4 ft-long box is part of a $20 million package of cameras, probes and computerised dust-catchers.

Not all of the monitors of this experiment package deal with inanimate atomic particles. Pilot Gordo Fullerton described the OSS.

“We have two payloads mounted in the payload bay, approximately 500 lb packages. We are planning to grapple those; that is, grab onto them with a fixture at the end of the manipulator arm, manoeuvre them to various positions outside the payload bay taking scientific and environmental measurements and bringing them back and reberthing them in the payload bay.”

Fullerton added, "In the launch and entry area we are going to be expanding the envelope (by) flying a trajectory that is more demanding on the vehicle and paving the way for heavier payloads on later flights. And then during the re-entry executing additional manoeuvres to further understand the aero¬ dynamics and handling qualities of the Orbiter during that phase of the flight. We will really be examining the full range of the capability of the manipulator arm, although not with its maximum capability.”

Commander Lousma provided an overview of crew activities for the third orbital flight test: “We certainly plan to sleep as much as required. But you find when you’re up there that you have such a short opportunity to be there and you're not there that very often it’s hard to go to sleep at night and you want to look out the windows to see the spectacular view. And so I think that some of the wake time is planned and some of it unscheduled, but we plan to use a sleeping bag on this flight and have one person sleeping at the controls. And we will try to maintain a more rigorous schedule as far as eating and sleeping are concerned. The second crew (Engle and Truly) told us that you had to plan more time for getting the meals ready and handling message traffic.”

One of the many television sequences planned for STS-3 includes an attempt to film the thrusters of the Reaction Control System firing. John Young has previously described the firing of the forward RCS jets as “sounding like a muffled howitzer going off, with a blue flame shooting out about 40 ft.” Television planners hope to be able to capture the same sort of sight if they are able to focus cameras on the systems.

NASA 1982 LAUNCH SCHEDULE

NASA planners have-an ambitious launch schedule for 1982: 12 expendable vehicle launches and three Space Shuttle flights, including the first operational mission.

Of the 12 expendable vehicles, seven are Delta rockets, three Atlas Centaurs and two Scouts. One of the Deltas will be launched from Kennedy Space Renter facilities at Vandenberg Air Force Base, Calif., and will carry the only non¬ communications satellite to be launched this year.

The launch scorecard for 1982 began in January with RCA-C aboard a Delta. February saw another Delta, this one boosting Westar IV into orbit.

March begins with an Atlas Centaur rocket with the Intelsat V F-4 satellite, and near the end of the month the third Space Shuttle mission is scheduled.

April and May will have a Delta to launch lnsat-1A and an Atlas Centaur for Intelsat V F-5.

In June, a Scout rocket will launch* a Defense Department Transit satellite from Vandenberg.

July will have two launches: an Earth resources satellite, Landsat D, aboard a Delta from Vandenberg, arfd the fourth Space Shuttle mission (STS-4) from Kennedy Space Center.

In early August Telesat F (also called Anik D), a Canadian communications satellite, will be launched on a Delta rocket.

In late September, Westar V will be launched on a Delta.

November will see the fourth Delta in a row, with RCA E as its payload, and will be highlighted by STS-5, the first operational mission of the Space Shuttle. That flight is listed as carrying two communications satellites, SBS C and Telesat E, and their boost stages plus an experiments pallet, OSTA-2. The mission is scheduled to last five days.

Also in November, the year’s second Scout launch will orbit San Marco-D/L, a joint NASA/Italy project designed to study the relationship of solar activity to meteorological phenomenon.

NASA will supply the launch vehicle while Italy supplies the satellite which will be launched from Italy’s San Marco launch site off the coast of Kenya.

The last launch of 1982 is now listed as an Atlas Centaur, carrying Intelsat VA F-l, the third Atlas Centaur-Intelsat combination for the year.

The Westars are being launched for Western Union, the RCA satellites are part of the RCA Satcom Network, the SBS series is owned and operated by Satellite Business Systems, the Telesats are being orbited for Telesat Canada and the Insat will be launched for India.