March 1980:the future of the Space Shuttle

From an original estimate of $857.2 million, Office of Space Transportation Systems spent an actual sum of $1,098.9 million during the financial year just ended. In an earlier report,FY1980 was said to need $511.3 million for Shuttle R&D.Based on worsening financial profiles, NASA has now revised this upward by $176 million, an increase of 34.4%.

Impact on Future Budgets

The history of percentage increases for FY1976 to FY1980 is now as follows: 0.08%; 7%; 11.5% 28.2%; 34.4%. It is unlikely that NASA will need to ask for more money in the FY1980 budget, although that period only began last October 1. What is uncertain, however is the impact on future budget years.Administrator Robert Frosch already believes the FY1981 and 1982 budgets will need between $200 million and $270 million per year extra, above the estimates already made for those two periods. Additional sums requested for FY1979 and FY1980 have clouded plans for early availability of the second Orbiter,called Challenger. Originally accommodating availability in February 1981, the FY1979 supplemental deferred Challenger by seven months. The FY1980 problem has now put Challenger back to March 1982 at the earliest. The third and fourth Orbiters - Discovery and Atlantis - are expected to be available in late 1983 and late 1984 respectively, more or less as planned.

Significant cost increases

Speaking earlier this year before the Senate subcommittee on Science, Technology and Space, Robert Frosch revealed that “Significant cost increases were disclosed by the Rockwell International Corporation, the Orbiter prime contractor, in October 1979,followed by similar increases for the other Space Shuttle elements ...” Frosch said that NASA "intended to handle these identified increases within our planned reserves, and if the schedule had been maintained, the reserves probably would have been sufficient. However, it has become clear that additional funds must be expended in FY1979 for the Design, Development, Test and Evaluation (DDT&E) phase and additional DDT&E resources in FY1980 are also required.”

Dr. Frosch itemised the prime offenders in delaying both mission operations and effective cost control:

(1) "A combination of technical problems and schedule extensions have caused substantial cost increase in subsystems such as the leading edge thermal protection system (LTV),the orbital manoeuvring engine (Aerojet) and the reaction control thrusters (Marquardt).”

(2) "The Orbiter KU band communications/rendezvous radar system implementation was previously delayed until the flight of STS-8 (author’s note: the eighth manned flight). However,the design and development effort for the KU band (Hughes) was substantially underestimated and additional effort is now required in FY1980.”

(3) “The development of the S-band communications system (TRW) to be used for payloads has encountered a number of technical problems and is more complex than originally thought, thus requiring more effort.”

(4) "A partial redesign is required on the auxiliary power units (Sundstrand) to institute an active cooling system to provide the capability for rapid restart of the system in flight.”

(5) “The Honeywell flight control effort was substantially increased in FY1980 based on our experience in FY1979. Additionally, as a result of the experience in FY1979,and the schedule delay in STS-1, overall subcontractor support and analysis activities will be retained for a longer period of time and at a higher level than previously planned.”

(6) "Additional Orbiter and systems integration engineering support (Rockwell International) throughout the flight test programme, and increased manufacturing personnel to complete mission kits (unique flight, test and/or support hardware) that were previously planned for FY1979.”

(7) “The Orbiter qualification and certification test programmes have also experienced delays. Priority is being given to completing those tests designed to certify subsystems for the first test flight.”

(8) “As a result of the main liquid oxygen valve failure in the main engine last December, it has been necessary to further delay the main propulsion system test. These tests, to verify propulsion system performance at main engine operation of 100% rated power level, will extend from FY1979 to FY1980 and additional tests have been added to certify the system at the 109% rated power level.”

(9) “The astronaut suit, extravehicular mobility unit (EMU),and the portable oxygen system have experienced cost growth and schedule delays. The original Hamilton Standard contract estimates were optimistic and have been significantly affected by vendor cost escalation and delays.”

(10) “The increased number of astronauts, requiring some small size units, has made it necessary to increase the number of sizes of EMU components and therefore increased our cost and schedule estimates. A recent EMU failure during astronaut training exercises in the water tank at JSC has further delayed this effort and added cost.”

(11) “The external tank (ET) portion ... is principally attributable to unexpected cost increases in the manufacture and application of the thermal protection system (TPS) in FY1979, and the need to further improve the system. Manufacturing manpower greater than planned will be required through FY1980 for TPS application."

(12) "The Launch & Landing increase ... is necessary to sustain a larger workforce for launch operations than previously estimated. This requirement is based on our experience to date, which includes more development contractor personnel and overtime than previously projected.”

(13) “Due to development motor manufacturing and subsystem qualification test problems, the Solid Rocket Booster manufacturing and assembly programme was impacted by increased manpower and overtime usage. The deliveries have slipped approximately two months.”

Largely as a result of welcome management changes at a number of locations the Shuttle is expected to fly the first development mission in the spring. Schedule boards set the flight for late March, but many expect that to realistically translate into a April-May flight period. But that date too would have been deferred had NASA chosen to develop an ability for thermal tile inspection on orbit. Tested beyond the maximum dynamic pressure anticipated for the first flight by tile samples applied to F-104 and F-15 aircraft, NASA plans to introduce an external inspection capability from the second flight. That will involve a Manned Manoeuvring Unit developed by Martin Marietta; plans for a television inspection by remote manipulator arm have been abandoned.

Effect on Future Programmes

In the four-year period 1979-1982, NASA will have spent an extra $900 million on Shuttle development, a sum almost equal to that spent on the development of Project Viking. And it is the impact on future missions planning that concerns NASA the most in a climate of increased financial stringency from the White House. Moreover, any change in the leadership of a Democratic administration is likely to bring an even less acceptable attitude, for Edward Kennedy is a critic of America’s space programme from the very days when John F. Kennedy set Apollo on a road to the Moon. But how do inflated Shuttle needs impact pending programmes? Deeply.

Only a year ago NASA hoped to begin work on the VOIR - Venus Orbiter Imaging Radar - spacecraft. Designed to use Seasat technology for probing the opaque atmosphere of Venus to construct a topographic map of the planet, VOIR would have been launched by Shuttle in 1984 had the agency been allowed to request a funded start in FY1981. That period begins next October, and NASA has just completed talks with the Carter administration about projects for that period prior to public announcement of the total federal budget in January 1980. It is unlikely that the agency will be allowed to make a start on VOIR, and because the launch opportunity for the mission profile will not re-emerge until late in the decade, NASA will be unable to sustain momentum in the exploration of Earth’s sister planet.

Moreover, because additional funds are required to support the Shuttle, over and above sums already budgeted in the five-year planning documents, it is unlikely that NASA will begin work on the Halley comet rendezvous project before FY1982.That is perilously close to the required launch date of mid-1985. Under plans now formulated, a single spacecraft will fly by solar electric propulsion to a close pass of the comet in December 1985, releasing a probe into its coma. Trajectory corrections will be made to steer the spacecraft on to rendezvous with Tempel II in December 1988, and to remain alongside the comet for six months before moving in for a landing.

The opportunity to achieve such a multitude of mission capabilities will require timely development of the Halley launch window, for if cometary exploration is left for later in the decade, funding costs will be the same while the richness of the mission will be severely depleted. But further than this,the funding supplement now thought necessary for Shuttle threatens to eject other planetary options from the decade’s shopping list. After VOIR, and the comet flight, NASA plans to ask for money in support of a Saturn-orbiter-dual-probe mission. This envisages a five-year flight to Saturn culminating in release of an entry probe prior to orbit insertion about the ringed planet.

Later, a second probe would be released into Titan’s atmosphere for the first scientific survey of this fascinating moon. The orbiter would continue to observe the Saturnian environment over an extended period. Just two years ago, prior to the request for additional Shuttle money, NASA's five-year planning schedule envisaged a funded start on the Saturn project in FY1983. One year later it was clear that the Saturn project could not receive funds as planned and the programme was put back to FY1985 at the earliest. Because the mission requires a four year development period and a five year trip time, it will not be possible to get orbiter or probes to their destination before 1994 - thirteen years after the last Voyager departs - at the earliest. And, it should be stressed, there is no guarantee of getting money for this in 1985. Similarly ejected from the five-year shopping list is NASA’s plan to explore Mars, a priority recommended by the Space Science Board of the National Academy of Sciences. In the August-September Spaceflight report it was said that funds would be requested in 1983 at the earliest for work on the sample-return programme. That date has now been put back to 1985 at the earliest which means that a precursor flight with geologic probes cannot now get to Mars before 1990, and that a sample-return vehicle would not reach the Red Planet before 1992; it would be 1995 before Mars material arrives on Earth. Again, this presupposes a funded start in 1985, the very earliest date NASA’s optimistic shopping list will permit.

The Plight of Galileo

But future projects are not the only ones exposed to competing needs of the Shuttle development programme, for increased weight in the transporter hardware is forcing current projects to seek more money also. NASA’s only planet mission currently approved but not yet launched is the Galileo flight originally planned for early 1982. That cannot now take place because the Shuttle is incapable of lifting spacecraft and booster to Earth orbit.

Utilising an Inertial Upper Stage, Galileo was expected to weigh approximately 2,060 kg of which 1,700 kg would be taken up by the orbiter bus and 245 kg by the probe; the balance would be absorbed by the IUS adaptor and a mission reserve of 15 kg. About half the bus weight was to be taken up with propellant to brake the vehicle into Jovian orbit, so little remained for a weight reduction effort (a large saving in vehicle mass would bring about a smaller reduction in propellant mass). To inject a mass of 2 tonnes on to a trans-Jovian trajectory would have required a three-stage IUS weighing about 25 tonnes. Accordingly, the total payload mass to Earth orbit would have been about 27 tonnes. Well within the advertised Shuttle lifting capacity of at least 29 tonnes. However, it has become clear in recent months that serious weight growth in the Shuttle, plus an initially conservative engine performance, provides the Orbiter with a serious payload deficit. When Columbia flies it will be limited to payloads totalling no more than 17 tonnes. By early 1981 it is hoped that tests with main engines will have increased this to about 19 tonnes by allowing a thrust level of 109% to be applied after liftoff. About six months later, it is hoped that still more testing will permit 109% throttle settings before liftoff, raising payload capacity to about 23 tonnes. But this is still far short of the 27 tonnes needed to get Galileo spaceborne. Up to mid-1979 NASA counted on availability of the second operational Orbiter,Challenger,which was to have been ready by 1981, to bridge the capability gap: weight reduction in Challenger should give this vehicle a payload capability of 27 tonnes. But now, because NASA borrowed from production money to settle development bills, Challenger will not be available before spring 1982. Galileo’s launch window ends in February of that year. And the alignment of the planets prevents even the full capability lUS/Shuttle configuration from flying a Galileo type vehicle again before the mid-1990s. Once missed in early 1982 the window is closed for more than a decade.

So where does that leave Galileo? Options centre on two configurations: separate orbiter probe vehicles launched in 1984 on two Shuttle flights; or development of the cryogenic Centaur stage for this and other planetary objectives. If launched as two flights, re-development costs plus launch fees for a second mission could cripple the attempt. In any event that would call for a postponement until 1984 at the earliest;

NASA has an international solar-polar project for launch in 1983 which would require two separate missions and three space vehicles to fly to the same planet simultaneously, and in any event the weight improvements are not expected before 1984.

As an alternative, the orbiter could fly in 1984 followed by the probe vehicle in 1986, an optimum mission sequence as far as costing goes and one favoured by some Congressional supporters. The less probable alternative would give planetary mission planners availability of the Centaur liquid propellant stage, a booster many wanted from the beginning when transportation needs centred on a solid propellant commonality for all Shuttle boost units. And it would give a payload increase over the solid IUS. But development for Shuttle use, plus modifications to adapt the Orbiter for cryogenic handling,could top $200 million, rendering this an unlikely option. If adopted, however, the complete orbiter/probe Galileo originally planned for a 1982 flight could get away in 1987 after minimum-cost development time.

Inevitably, any delay in getting Galileo operational will have serious repurcussions on the health of programme offices at CalTech’s Jet Propulsion Laboratory. Already, with little probability of getting VOIR in the forseeable future, managers are worried about the momentum falling off where success and proficiency depend to a large extent on pace and “negative slack” in the schedules. As it stands, after two Saturn encounters the only programmes currently approved foresee a possible inspection of Uranus in 1986 Neptune in 1989.

But if planetary programmes can be juggled for appropriate launch capabilities, military missions for the mid-1980s are not so flexible and NASA is obliged to provide the Defence Department with a so-called Mission 4 capability by June 1984. Mission 4 stipulates a 14.5 tonne payload delivered to a circular 278 km orbit inclined 98°, provision of an on-orbit AV of 320 metres/sec, and retrieval and return of a 11.3 tonne payload from that orbit. It is a requirement stimulated by the Big Bird successor now in development and one that is equivalent to a 29.5 tonnes load placed in a low due east orbit from the Kennedy Space Center. To accommodate this requirement an extensive weight saving programme envisages up to 2,270 kg removed from the dry Orbiter mass, up to 2,720 kg removed from the ET, 317 kg taken from each SRB and 91 kg saved from each main Orbiter engine. Maximum weight savings would be applied to the third and fourth operational Orbiters - Discovery and Atlantis - with lightweight tank and boosters available for Columbia and Challenger some time in 1982. However, gross payload capability will increase by 900 kg for the second and third Orbiters,respectively. Savings in the External Tank will stem from a reduced safety factor of 1.25 from a current 1.4 times design load. Stringers, slosh baffles, aft dome caps, intertank, andnthermal protection areas can be significantly thinned out by relaxing constraints. With these improvements, payload to due east orbit is expected to be 26 tonnes by 1982. Mission 4 requirements were to have been met by the third Orbiter but Discovery will now have only a 28.2 tonne due east capacity even with lightweight tanks and SRBs; the additional 1.2 tonnes comes from improvements in Orbiter fabrication compared with the previous vehicle (Challenger). It is necessary, therefore, to employ a supplementary propulsion system to improve the Shuttle’s carrying capacity to the level where it can match the Mission 4 requirement. This comes in the form of Strap On Solid Motor (SOSM) assemblies, one attached to each SRB,raising due east capacity to approximately 32.2 tonnes for a 98° potential of the required 14.5 tonnes. NASA hopes to begin development by mid-1981 so that SOSM configurations are ready by mid-1984. If additional strap-ons were clustered beneath the External Tank, payload capacity would increase to 28.5 tonnes and 20.4 tonnes for due east and 98° orbits,respectively.

But that is a future option without consideration for hardware development at present. As it stands, Shuttle operations will be limited to (due east) payloads of 17 tonnes until early 1981, when it will grow to 19.5 tonnes, increasing to 23 tonnes later the same year. By 1982, capacity should be 27 tonnes and in 1983 that should increase to 28.2 tonnes when Discovery becomes available. Capacity would be 32.2 tonnes by 1984 if SOSM developments evolve as planned. Although deficient in early years, the original requirement for a 29.4 tonne payload should be met and significantly improved by implementing modest development efforts.