Post 8: Return to Flight
“A ship in harbor is safe, but that is not what ships are built for.”
- John A. Shedd, 1923
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The Challenger accident led to a reorganisation of the American space programme, but no major change of direction. The reduction of the shuttle fleet from five to four orbiters, as well as the year-long hiatus in crewed launches while mitigation actions were taken to prevent a recurrence, was the final nail in the coffin of the shuttle’s commercial ambitions. The demands of the Skylab, Freedom, and DoD commitments meant that there was simply no room in the manifest for commercial users. A Presidential directive in October 1986 finally made it official, directing that NASA sign no more commercial launch contracts with industry. In future, US commercial launch needs would be met by privately operated (though still heavily subsidised) Atlas, Delta and Titan rockets.
The first Space Transportation System mission following the return of Enterprise was a Shuttle-C launch out of Vandenberg in February 1987. This mission carried a classified military payload (widely, and correctly, assumed to be a large aperture optical telescope), and was designated STS-26C (STS-25 having been skipped, acting as a placeholder in the mission sequence for the STS-500 rescue mission). With the agreement of the DoD, NASA used this mission to test a number of modifications to the configuration of insulating foam on the shuttle External Tank, with the aim of reducing foam loss at launch. Although not perfect, these modifications showed a marked improvement over the pre-Challenger baseline, and were quickly approved for use on crewed shuttle flights, with additional modifications to the ET foam placement made based on observations of the STS-26C launch.
Five months later, in July 1987, the shuttle orbiter fleet returned to space with STS-27. Despite it being almost a year since the launch of the STS-500 rescue mission, this return to crewed flights came sooner than many at NASA were comfortable with, but was driven by a need to return to Skylab and secure the station. Although Skylab-B was designed to operate autonomously for at least a year between shuttle visits, its use as an emergency shelter had seen several unusual deviations from its standard configuration, as well as depleting on-board consumables. There were also belated concerns that some of the experiment racks transferred from Challenger to the Skylab Node could create a hazard if left unattended for too long. This led to pressure from the leadership to revisit the station as soon as possible to avoid the risk of this unique orbital asset being lost.
The STS-27 mission saw Discovery and her crew of five resupply and secure the station, and also tested a number of new safety innovations, such as an extension to the RMS robotic arm that would in future allow tiles to be inspected and repaired without the need for risky untethered space walks. On Skylab itself, Discovery’s crew retrieved many of the experiments that the crew of Challenger had relocated from their Spacelab module to the station. They also transferred more than three tonnes of supplies to the station, mostly consisting of propellant for the orbital manoeuvring system, but also atmospheric gasses, food and water. This was intended to both replenish those consumables used during the crisis, and to build up a more robust stockpile should Skylab be needed as a safe haven again. By the end of their three-week mission, the space station was in good shape and ready for the expanded expeditions that NASA had planned for the future.
A key part of those future missions was to transition Skylab from a place that could be periodically visited into a permanent home in space, as Zarya-3 was for the Soviets. With the limits imposed by the shuttle’s reflight rates and on-orbit endurance, that would mean leaving a crew aboard Skylab for periods when there would be no orbiter docked to the station. The solution was to provide a lifeboat, or Assured Crew Return Vehicle, that could bring the station’s crew home in an emergency, and the Freedom return vehicle capsule under development for NASA’s lunar missions would be a perfect fit.
The space shuttle Atlantis lifted off on mission STS-28 in late October 1987, carrying Freedom capsule RV-102 in its payload bay. The stumpy cone-shaped ship, looking like a smaller copy of an Apollo command module, was actually the second Freedom capsule to enter space. It’s sister ship, RV-101, had made an uncrewed launch into a highly elliptical orbit by a Titan 3E booster in March 1986 to validate the thermal protection system when making a re-entry at lunar-like speeds. That test had been a success, and RV-102 was to have been carried to Skylab in the fall of 1986, before the Challenger incident introduced a delay. Now Atlantis would complete that mission, using its RMS arm to dock the five-tonne capsule at the earth-facing port of Skylab’s Power and Docking Node.
After completing their regular scientific mission, the crew of Atlantis departed in mid-November, leaving RV-102 behind at the station. The capsule remained in place throughout the STS-29/Columbia mission in February 1988, finally undocking under ground command the following April. The capsule then returned to Earth under automatic control, splashing down off the coast of Florida after six months in space, simulating the expected standard duration that lifeboats would be left aboard the station.
The RV-102 mission cleared the way for long duration Skylab expeditions to start in 1989, but also contributed to the advancement of the Freedom programme. Although President Reagan’s ambition to see Americans return to the Moon during his term of office was no longer feasible, the programme was making steady progress, with testing of the uncrewed Earth departure and lunar landing stages planned on a Shuttle-C mission in late 1989. This would be followed by crewed orbital test flights of the surface logistics and return vehicles starting in 1990. If all went to plan, 1991 would see the return of American boots to the Moon.
As NASA’s shuttle was returning to normal operations, its Soviet equivalent was also making steady progress. The 2K1 Urugan/Slava mission of February 1987 was followed in August by mission 1K2, and the first crewed launch of the N1-OK/Baikal system. This mission used the second orbiter, vehicle 1.02, now named “Tsiklon” (Cyclone), and was piloted by cosmonauts Igor Volk and Magomed Tolboyev. The mission saw Volk and Toboyev orbit the Earth sixty times as they tested the orbiter’s systems, including the deployment of a geophysics satellite. Despite some speculation in the Western media that Tsiklon would dock with Zarya-3, the shuttle stayed well clear of the station during its four days on orbit. Official press releases from the Soviets indicated that the shuttle was not yet equipped with the necessary docking apparatus for a mission to Zarya. In actual fact, the issue was that Tsiklon was simply too big to approach the nuclear-powered station and remain within the reactor’s cone of safety. Docking at the station would leave Tsiklon’s tail exposed to an elevated level of radiation, and there were concerns that this could affect electronic equipment in the aft section, or even scatter radiation in unexpected ways that could harm the crew. For this reason, Volk and Tolboyev returned to Earth without visiting their comrades in Zarya, bringing the spaceplane down on the runway at Baikonur to the applause of the Soviet press.
The celebrations of the successful mission masked the fact that the decision to fly cosmonauts on only the third launch of the Soviet shuttle had been a controversial one. The original test plan had called for at least four uncrewed launches before putting cosmonauts on the pad, but Mishin over-rode the concerns of his deputies to approve the mission. The Soviet economy was straining under the burden of its enormous military budget, as well as the dislocations brought by Gorbachev’s reforms, and Mishin was feeling the pinch. Not only did he have the Baikal shuttle and the lunar exploration programmes to advance, he had also been tasked with yet another “national priority” mission to prepare some sort - any sort - of response to Reagan’s “Battlestar America” missile defence programme. Problems with scaling up the production of N1 rockets meant that only three or four of the giant rockets could be made ready each year, leaving all of these political priorities competing for rides on a limited number of launchers. Sticking to the original plan under these conditions would have meant no crewed shuttle missions until the 1990s, while the Americans would be launching shuttles every two or three months and making twice-yearly lunar landings. Mishin’s political standing depended on him delivering propaganda spectaculars. If he didn’t deliver, then Glushko surely would.
With the crewed flight of the orbiter Uragan on a week-long bioscience mission in December 1987, Mishin was ready to declare the Baikal shuttle system operational and switch focus back to the moon. It had been three years since the last Soviet (and French) boots had touched lunar soil. With the upgraded N1-OK launcher performing well, it was finally time to take Barmin’s lunar habitat out of storage and establish the first permanent outpost on the Moon.
The first part of this base complex, the Power and Habitat Module, or EZA, had been ready at the Baikonur cosmodrome since late 1986, but it was only in March 1988 that the N1-38L carrier was rolled out to pad 37 with the EZA at its tip. The rocket’s twin, N1-39L, was already at pad 38 with the GB-1bis upper stage that was needed to push the lunar base on its descent towards the Sinus Iridium. The two rockets lifted off two weeks apart in April 1988, with both the habitat and the descent booster being delivered to their correct lunar orbit. The EZA then performed a delicate automatic rendezvous with the upper stage, the first such attempt without having cosmonauts able to take over in an emergency. Fortunately, the simple, reliable Kontakt system proved its worth once more, and docking proceeded without a hitch. Shortly afterwards the stack blasted itself out of lunar orbit on a trajectory to the Bay of Rainbows. Discarding the spent GB-1b stage, the EZA stage touched down on Friday 29th April 1988. Radio Moscow announced the landing to the world, declaring the foundation of “Lunnyy Gorodok”, or “Moon Town”, and announcing that cosmonauts would be visiting the base “in the coming months”.
Other events would soon change these plans.